Implanting Physician or Surgeon

Traditionally, pacemaker implantation procedures were performed exclusively by a thoracic or cardiac surgeon. The skills were acquired during a residency or fellowship. Early pacemaker implantations involved more extensive surgery and, at times, an open-chest procedure for placement of epicardial electrodes. The pulse generator and electrodes were large, requiring considerable dissection and surgical skill. Since 1980, diminishing pacemaker size has limited the more extensive surgery previously required. At present, the knowledge and skills required for dual-chamber pacing are well suited for the physician trained in cardiac catheterization.

It is generally accepted that the pacemaker-implanting physician may be either a thoracic surgeon or an invasive cardiologist.⁶ At times, the two may even act as a team, with the surgeon isolating the vein and the cardiologist positioning the electrodes. With the current reimbursement structure and the changing economic environment, however, this team approach is rapidly becoming burdensome; in any event, it is frequently unnecessary. Currently, the credentialing for pacemaker implantation procedures poses a dilemma. The trainee in thoracic surgery has ever-diminishing exposure to pacemaker implantation as the procedure becomes more the responsibility of the cardiologist. At the same time, the cardiologist has little or no exposure to proper surgical technique, the use of surgical instruments, and preoperative and postoperative care. Although controversy surrounds the appropriate implantation experience and its length, physicians with limited training and ongoing experience apparently have higher complication rates.⁷ To remain proficient, the physician should perform a minimum of 12 procedures per year.

In a single-center study of more than 1300 permanent pacemaker implants, Tobin et al.⁸ reported complications in 4.2% of patients. The economic impact was substantial. Most importantly, there was an inverse relationship between the incidence of acute complication and implanter experience and case volume. Similarly, complications associated with elective generator replacements, revisions, and upgrades have been directly related to operator experience. Harcombe et al.⁹ found a higher rate of late complications after elective replacements (6.5%) compared with initial implants (1.4%). This higher rate was clearly related to operator inexperience.

There is a definite need for formal training programs specifically designed to teach cardiac pacing.^10–12 Such programs should be offered to both cardiologists and surgeons interested in cardiac pacing. The ideal program should be comprehensive and integrated, involving not only all implantations but also follow-up and troubleshooting. To be an effective implanter, the physician must understand the problems of follow-up and troubleshooting. Formal didactic experience and hands-on exposure are necessary. Although a formal, year-long, comprehensive, integrated training program is ideal, consideration of physicians who are out of formal training programs sometimes requires combining more intensive didactic programs with extended, supervised hands-on experience. Training is important for the implantation and nonimplantation aspects of pacing. We see substantially less enthusiasm for the presurgical and postsurgical aspects of pacing. We ardently believe such mastery is crucial to becoming an effective implanter.

Regardless of how physicians have been trained to implant pacemakers, careful review of their training and experience by those granting privileges at the institution will help prevent inadequately trained individuals from performing independent, unsupervised pacemaker implantation. Criteria for adequate training and experience should involve a minimum number of pacemaker procedures, including single-chamber and dual-chamber implantations, lead replacements, pulse generator replacements, and upgrades to dual-chamber from single-chamber systems. Also, some documentable experience in an active pacemaker service clinic should be required.¹³ An electrophysiology (EP) fellowship is one way of obtaining these skills, and physicians trained as surgeons, pediatricians, radiologists, and cardiologists have access to this training. Credentials can include the EP boards under the jurisdiction of the American Board of Internal Medicine, the Certified Cardiac Device Specialist examination by the International Board of Heart Rhythm Examiners, and cardiothoracic (CT) surgical boards, but only for pacemakers, not ICDs.

Support Personnel

Support personnel are crucial to the success and safety of any pacemaker procedure. Historically, whether in a large medical center or a small community hospital, the procedure was performed in the operating room (OR). This had its drawbacks because each case could be a first-time experience for the OR staff. Pacemaker procedures were often added at the end of a busy OR schedule and were assigned to the first available room with support personnel, who changed from procedure to procedure. Personnel not familiar with the procedure can interrupt the flow of the case. Even with the transition to the cardiac catheterization laboratory (CCL) for pacing procedures, the same problems can apply. Conversely, depending on the volume of procedures in the OR and CCL, there may be more opportunity for consistent, recurrent availability of cardiovascular technicians, nurses, and radiography personnel in the CCL. These more focused staff members tend to have a certain appreciation for the procedure and are better equipped to deal with the unique problems that may be encountered during pacemaker implantation.

Whether implantation takes place in the OR or CCL, the minimal personnel required are the same, as follows:

It is also useful to have access to an experienced cardiovascular radiology technician, which generally is more easily accomplished in the CCL than the OR.

The presence of an anesthesiologist or nurse anesthetist (CRNA) is inconsistent. Initially an essential member of the implantation team, an anesthesiologist in many centers is now involved only in special situations requiring airway support in an unstable or otherwise problematic patient. As ICDs, biventricular devices, extraction procedures, and other patients with unstable hemodynamics have become more common, each patient should be assessed for the need for support before the procedure. Anesthesiology staff should always be available for emergency situations and consulted if problems are anticipated.

The participation of the manufacturer’s representative as support personnel has always been a subject of debate. This person’s role varies from center to center.¹⁴ At one extreme, the representative merely delivers the device and leads to the hospital. At the other extreme, the person is a vital member of the support team, retrieving threshold data, filling out registration forms, and at times, offering technical advice. The latter extreme is particularly true in smaller institutions with less pacemaker activity and in-house support of ICD implantation. A well-trained manufacturer’s representative can be an important member of the support team. An experienced representative dedicated to cardiac pacing and ICD implantation typically has broad experience and a knowledge base in problems unique to the company’s products. Although such a representative of industry can be helpful, this person, no matter how experienced or knowledgeable, should not be considered an acceptable alternative to a knowledgeable, skilled, and experienced physician implanter. If an industrial representative is to be used during implantations for support, hospital approval is advisable.

Comparing OR and CCL support personnel requirements, besides the CCL’s previously noted general advantages, another important concern is sterile technique. The regular OR personnel tend to be more keenly aware of sterile technique and are scrupulous in this regard. In contrast, CCL personnel are not routinely trained in OR and sterile techniques, and if not strongly reinforced, these procedures can be disastrously neglected.

Inpatient Versus Outpatient Procedure

With all documentation obtained and indications met, the next step is scheduling the procedure. Pacemaker and ICD surgery can be performed on either an inpatient or an outpatient basis. Traditionally, even pacemaker procedures were done on an inpatient basis, which involves formal admission of the patient to the hospital for the procedure. The preoperative evaluation (in most cases), the device procedure, and early postoperative care are carried out in the hospital. Generally, the patient has already been admitted to the hospital because of symptoms (e.g., syncope) and the diagnosis of a bradyarrhythmia subsequently established. The device procedure is then scheduled. Alternatively, the evaluation is mostly or partly completed before admission; after the need for a pacemaker is determined, the patient is admitted for the pacemaker procedure and postoperative care. In some cases, this inpatient approach is inefficient and not cost-effective.

The early pacing systems were large, had brief longevity, and were prone to catastrophic complications, such as lead dislodgement, perforation, and wound infection. Postoperatively, therefore, patients were managed with extreme caution; an abbreviated hospital stay seemed radical, and an ambulatory procedure was unthinkable. Currently, complications are rare; pacemakers and even ICDs are small; venous access is easy and quick with the introducer technique; and the procedure is relatively minor. Refinements of the electrode systems with active and passive fixation have reduced the dislodgement rate to near zero. In addition, the indications have been expanded to include more patients who are less pacemaker dependent and for prophylactic purposes. Lastly, and perhaps most directly, there is a growing mandate for cost containment. The very technologies that have made cardiac pacing and ICDs physiologic, reliable, and safe have resulted in higher cost. For all these reasons, it seems logical that an ambulatory approach for device procedures could be safe and effective as well as less expensive.

There is a trend toward performing pacemaker procedures on an ambulatory basis. The experiences at several centers, in both Europe and the United States, have clearly supported the safety and efficacy of this approach.^24,25 Concerns about potential complications continue to be expressed.^26–28 Questions about lead selection, the timing of discharge, and the intensity of follow-up are frequently raised. In addition, the economic impact has yet to be fully appreciated. Although more ambulatory pacemaker procedures are being performed, this has not been reflected well in the pacing literature. Since the original reports of Zegelman et al.²⁴ and Belott,²⁵ Haywood et al.²⁹ have reported a randomized controlled study of the feasibility and safety of ambulatory pacemaker procedures. Although the study group was small (50 patients), the results were similar to those of one of the authors (PHB). There was good patient acceptance, no evidence of a higher complication rate, and cost savings of £540 (at that time, about $810 U.S.).

Since the initial report of 181 new pacemaker implants in 1987, our own ambulatory experience continues to be gratifying. During a 13-year span reported in 1996, that experience comprised 1474 pacemaker procedures, 1043 (69%) of which were performed on an ambulatory basis.³⁰ The experience also included pulse generator changes, all of which we have performed on an outpatient basis since 1987. Our experience indicates that 60% to 75% of new pacemaker implantations can be successfully performed as ambulatory procedures (Table 21-2). There have been no additional ambulatory failures, pacemaker-related emergencies, or deaths in the ambulatory procedures. (An ambulatory failure is an implantation that is initiated as an ambulatory procedure, but for which the hospital stay is extended to admitting the patient because of a complication.) The complications encountered in ambulatory cases included one hemothorax detected 2 weeks after discharge, successfully managed by hospitalization and chest tube drainage. Three hematomas were managed on an ambulatory basis with reoperation, control of bleeding, and drain placement. Two small pneumothoraces that did not require chest tubes occurred fortuitously in hospitalized patients who had no planned ambulatory procedure.

These experiences underscore the safety of the ambulatory approach. At present, almost all elective pacemaker procedures (new implantations, electrode repositioning, upgrade procedures, electrode extractions, and pulse generator changes) are done on an ambulatory basis. A simple protocol is used, and the patients often go home 1 to 2 hours after the procedure. They are seen the following day in the pacemaker clinic. Box 21-3 outlines a simple outpatient protocol.

In most institutions, patients can remain in the hospital overnight and still be considered outpatients. This practice conforms to the present U.S. Health Care Financing Administration (HCFA) definition of ambulatory surgery for reimbursement in the United States, as follows: “When a patient with a known diagnosis enters a hospital for a specific minor surgical procedure or treatment that is expected to keep him or her in a hospital for only a few hours (less than 24) and this expectation is realized, he or she will be considered an outpatient regardless of the hour of admission, whether or not he or she occupied a bed, and whether or not he or she remained in the hospital past midnight.”³¹ An important caveat of ambulatory pacemaker procedures is that if there is any doubt or concern about the patient’s well-being, the hospital stay can be extended.

In the United States, the primary instrument for reimbursement is Medicare, administered by the Centers for Medicare and Medicaid Services. To limit fraud and abuse, a recovery system of private contractors was implemented, called the Medicare Recovery Audit program. With respect to pacemakers and defibrillators, the program has brought pressure to bear on hospitals to perform these procedures on an outpatient basis. Hospitals have been denied reimbursement on the basis of insufficient and inaccurate documentation of medical necessity as well as incomplete and improper coding. The denial of reimbursement has been challenged and reversed on a number of occasions. The fundamental issue is documentation. For this purpose and for all other regulatory and reimbursement purposes, clear documentation of indications for the device and the need for inpatient or outpatient procedures is essential.

Preoperative Patient Assessment

The preoperative patient assessment consists of the synthesis of all patient information, including history, physical findings, old records, cardiac rhythm strips, and laboratory data. With this information, appropriate decisions can be made about the pacemaker mode, leads, and general approach.

The first such decision is whether the patient requires a single-chamber or dual-chamber pacemaker. With the expansion of options in devices, physicians also need to consider whether the patient’s condition would be better served with an ICD or a cardiac resynchronization device. As a rule, if the patient has intact atrial function, every effort is made to preserve atrial and ventricular relationships. Single-chamber ventricular pacing is usually reserved for the patient with chronic atrial fibrillation or atrial paralysis. A device is selected with appropriate size, longevity, and programmability. If the heart is chronotropically incompetent, a device that offers some form of rate adaptation is considered.

Lead selection is equally important. One necessary decision is whether to use passive-fixation or active-fixation leads. Generally, an active-fixation electrode is selected when problems of dislodgement are expected, such as in the patient with a dilated right ventricle or amputated atrial appendage. Active-fixation leads are one of several factors that enhance removability of the lead, if it is necessary in the future. Also important is the pacing configuration (unipolar vs. bipolar). This decision relates to both electrodes and the pulse generator. Although the use of bipolar pacing and sensing has definite advantages, bipolar leads have historically been more complicated and prone to more problems. Bipolar leads are also larger in diameter. The compatibility of electrodes and the pulse generator is extremely important, particularly when using an original electrode with a modern pulse generator. If these are incompatible, an appropriate adapter must be obtained. Directly related to the device selection process is whether an ICD or CRT system should be placed. These decisions also affect the type of device selected and the lead systems employed.

If an ambulatory approach is being considered, the patient is assessed with respect to the risk of this approach. An unstable patient should always be admitted to the hospital. If the patient is critically ill, pacemaker dependent, or unstable, a temporary pacemaker is considered. It is usually better to take the few extra minutes and place a temporary pacemaker. Doing so can avoid moments of “terror” during the procedure if asystole occurs. This statement is particularly true in patients with complete atrioventricular block, in whom an apparently stable escape rhythm can suddenly disappear, a common situation after initial pacing has been established.

The timing of the procedure usually relates to the stability of the patient. In the critically ill patient in whom there are concerns about the stability of the cardiac rhythm or temporary pacemaker, an early permanent procedure is in order. Conversely, in a patient whose survival is in doubt, the clinician may appropriately decide to wait for stabilization. At times, the procedure is delayed because of systemic infection or sepsis. A permanent pacemaker implantation performed in a septic patient may lead to the seeding of bacteria on the pacemaker or electrode. If there is active infection, our approach is to defer the procedure until the patient is afebrile and no longer septic, to reduce the risk of pacemaker system infection.

Decisions with regard to the implantation site are not as important at present as when only large pulse generators were available. The currently available devices, weighing less than 30 grams, make the site, in most situations, moot. Devices tend to be tolerated well in almost any location. However, special circumstances deserve mention, including hobbies, recreational/occupational activities, cosmetic issues, and previous medical conditions. In the patient who hunts, for example, the pacemaker should be placed on the side opposite that of the rifle butt. Similar considerations are appropriate for the tennis enthusiast or golfer (although our experience with golfers indicates that placing the pacemaker on the backswing or follow-through side varies). In a young person, placement of the pacemaker under the breast (women) or in the axilla may be more desirable from a cosmetic point of view. Medical conditions, such as previous surgery, radiation therapy, and skeletal or other anatomic abnormalities, should also be considered. In the patient who is small with little subcutaneous tissue, a subpectoralis muscle (subpectoral) implantation may be required. This calls for the use of a bipolar system to avoid stimulation of skeletal muscles.

Preoperative Orders

The preoperative orders for pacemaker implantation are generally simple. The patient fasts for at least 6 hours before the procedure. If the implantation is an ambulatory procedure, the patient reports to the hospital on the day of the procedure, with enough time to obtain the necessary preoperative testing, generally 2 hours. The preoperative procedures consist of posteroanterior (PA) and lateral chest radiographs, an ECG, a complete blood count (CBC), prothrombin time (PT), partial thromboplastin time (PTT), and measurements of serum electrolytes, blood urea nitrogen (BUN), and serum creatinine. Because the patient is fasting, adequate hydration is maintained with a stable intravenous (IV) line. Hydration is extremely important for subsequent venous access and prevention of air embolization during the procedure. It can be frustrating and dangerous to try to gain venous access in a patient who is dehydrated after prolonged fasting without IV hydration. We generally request that the IV line be started on the side of the planned procedure, so as to facilitate venography during attempts at venous access if this becomes a problem.

The management of pacemaker surgery in the patient taking anticoagulants is controversial. Little information is available regarding management of a patient who requires anticoagulation. Clearly, however, the patient receiving anticoagulants, including heparin and platelet antagonists, is at risk for hematoma formation. It is generally held that in patients who require oral anticoagulants, PT should be normalized before implantation. Anticoagulant therapy can be resumed between 24 and 48 hours after pacemaker implantation. Reducing the PT to normal in a patient requiring anticoagulants (e.g., with artificial heart valve) creates a serious risk for thromboembolic complications. To address this issue, many operators choose to admit the patient to the hospital and start IV heparin while the warfarin is withheld and PT normalized. This process, called bridging, often takes several days. When the PT has reached the control value, the patient is scheduled for surgery. On the day of surgery, the heparin is stopped, and in some situations, the anticoagulation is reversed and the procedure carried out. Several hours postoperatively, the heparin is resumed. After 24 to 48 hours with no evidence of significant hematoma, the warfarin is then resumed; when therapeutic levels are reached, the heparin is stopped, and the patient is discharged with oral warfarin therapy.

In 2008 the American College of Chest Physicians (ACCP) published evidence-based practice guidelines for the perioperative management of patients receiving antithrombotic therapy,³² including vitamin K antagonists (VKAs) and antiplatelet drugs. ACCP recommends temporary cessation of VKAs and use of perioperative bridging anticoagulation with low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) for patients at moderate to high risk for thromboembolism and for those with a mechanical heart valve, atrial fibrillation, or venous thrombosis. There is no mention of uninterrupted VKA therapy. For the patient taking antiplatelet drugs who has bare-metal or drug-eluting stents and requires surgery within 6 weeks of stent placement, uninterrupted antiplatelet therapy is recommended. In patients who require temporary interruption of antiplatelets, treatment is stopped 7 to 10 days before surgery. It is recommended that antiplatelet drugs be resumed approximately 24 hours postoperatively. Frequently with pacemaker and ICD procedures, however, antiplatelet therapy cannot be suspended.

Cost controls and managed care can make this process problematic. In addition, despite vigorous attempts at hemostasis, significant hematomas have resulted from the use of heparin. This problem is anecdotal, but in our general experience, the greatest risks for bleeding complications, hemorrhage, and hematoma occur with the use of heparin or platelet antagonists such as aspirin. Having encountered a patient with a devastating thromboembolic complication caused by withdrawal of warfarin, as well as multiple large hematomas from the use of heparin, one of us (PHB) has chosen to perform pacemaker and ICD procedures with the patient still undergoing anticoagulation with oral warfarin. As a rule, patients taking oral anticoagulants have their international normalized ratio (INR) reduced to about 2. With this policy in effect more than 22 years, there have been no devastating hematomas or thromboembolic events. In a recent 13-year retrospective review of 458 device procedures on patients receiving continuous uninterrupted VKA therapy, there were only eight hematomas and no catastrophic hemorrhages or VKA-related deaths.³³ This gratifying experience underscores the safety and cost-effectiveness of continuous uninterrupted VKA therapy, which unfortunately remains unaddressed by current guidelines for cardiac implantable electronic device (CIED) procedures.

We believe that pacemaker and ICD procedures can be performed safely with the patient anticoagulated as previously described. Supporting this approach in a 4-year experience, Goldstein et al.³⁴ found no difference in incidental bleeding complications between patients receiving warfarin and those without anticoagulation. No wound hematomas, blood transfusions, or clinically significant bleeding occurred in any patients receiving warfarin. In a later, large series of patients, Giudici et al.³⁵ further substantiated the safety and efficacy of CIEDs without reversing warfarin therapy.

More recently, Ahmed et al.³⁶ demonstrated that interrupting anticoagulation is associated with increased thromboembolic events, and cessation of VKAs with bridging was associated with a higher rate of pocket hematoma and prolonged hospital stays. The authors concluded that continuous uninterrupted VKA therapy with a therapeutic INR was safe and cost-effective. Thal et al.³⁷ compared the incidence of hematoma formation among patients receiving continuous warfarin, aspirin, and clopidogrel therapy. Hematoma formation was rare, even among anticoagulated patients, although an increased incidence was seen in patients receiving dual-antiplatelet therapy. Dreger et al.³⁸ found CIED procedures to be safe in patients on dual-antiplatelet therapy but recommended the use of a drainage system. In patients requiring CRT, Ghanbari et al.³⁹ found uninterrupted warfarin therapy to be a safe alternative to routine bridging therapy, reducing risk of bleeding and shortening hospital stay. More recently, continuing warfarin in patients with a therapeutic INR was shown to be a safe, cost-effective approach compared with cessation of warfarin and bridging anticoagulation.

A new strategy is developing with the release of dabigatran in the United States. This direct thrombin inhibitor has the advantage of a short half-life and obviates the need for INR tracking. The RE-LY study demonstrated its efficacy and safety for patients with atrial fibrillation in comparison to warfarin.⁴⁰ At this time, no data are available on the impact of dabigatran on perioperative hematomas or the most appropriate perioperative management. However, witholding the medication for 24 hours before the procedure and restarting 24 hours later seems a reasonable initial approach.

The risks of interrupting continuous anticoagulant therapy with a resultant thromboembolic event can be substantial. Although hemorrhage is possible during and after pacemaker procedures in patients with therapeutic levels of anticoagulation, the risk seems minimal. The bleeding can generally be treated with local measures, such as the placement of drains or reoperation. Risk of bleeding is greatly outweighed by risk of thromboembolism after withdrawal of anticoagulant therapy. Pacemaker and ICD surgery in the patient receiving anticoagulant therapy is becoming more prevalent as more patients are prescribed these therapies for atrial fibrillation. The patient is instructed to continue maintenance oral medications, which may be taken with small sips of water. Patients taking a hypoglycemic agent are instructed to reduce the preoperative dose by 50%.

The administration of prophylactic antibiotics is controversial. We prefer intraoperative administration of a broad-spectrum cephalosporin (e.g., cefazolin). Others use vancomycin, which covers all gram-positive organisms. Approximately 50% of device infections are caused by methicillin-resistant staphylococci. Screening for Staphylococcus aureus nasal colonization helps in identifying patients at highest risk. The patient should scrub the chest, neck, shoulders, and supraclavicular fossae with a povidone-iodine (Betadine) sponge the evening and the morning before the procedure; the surgical area usually is shaved in the procedure room. Also, the patient should empty the bladder before coming to the procedure room.

Site Preparation and Draping

When effective patient support has been established, focus turns to the operative site. If not already accomplished, shaving and skin cleansing should include the neck, supraventricular fossae, shoulders, and chest. The operative site, shaved and cleansed, is now formally prepared and draped. A povidone-iodine (Betadine) scrub may be followed by alcohol, then povidone-iodine solution, with skin drying before applying the final povidone-iodine solution. Alternately, povidone-iodine gel is spread liberally over the operative site. Within 30 seconds, an optimal bactericidal effect is achieved. With this approach, scrubbing the area is not required. For patients allergic to povidone-iodine, a chlorhexidine (Hibiclens) or hexachlorophene (pHisoHex) scrub can be used.

Currently, many traditional scrubs have been replaced by either a povidone-iodine or a chlorhexidine and alcohol combination. These preoperative skin preparations have the benefit of a single, rapid application. DuraPrep is iodine povacrylex and isopropyl alcohol; ChloraPrep is 2% chlorhexidine and 70% isopropyl alcohol; both offer rapid-acting broad-spectrum protection. Because alcohol-based antiseptic solutions can act as fuel for surgical fires, the skin preparation must be allowed to dry, strictly observing recommended drying times. In addition, it is important to remove the fuel; surgical fires in the OR can result in patient burns and even death.⁴¹

The draping process is a matter of personal preference. One of the authors (DWR) applies a sterile, see-through plastic adhesive drape (impregnated with an iodoform solution) over the entire operative area. The other (PHB) uses one or more sterile plastic drapes with adhesive along one side (Fig. 21-7); the adhesive surface is applied from shoulder to shoulder at the level of the clavicle, which serves to create a sterile barrier from the shoulder level down. Depending on the situation, other barriers can be created. In both cases, the plastic drape is used to optimize sterility.

Figure 21-7 A, Application of a 3M (Minneapolis) 10/10 drape to create a sterile barrier. B, The drape folds over the support of common house (Romex) wire, creating an effective sterile barrier and preventing patient claustrophobia.

After some form of sterile barrier is established, the operative site is draped with sterile towels, and one or more large, sterile surgical sheets are applied. Care is taken to avoid smothering the patient and causing claustrophobia, best achieved by keeping the drapes off the patient’s face and maintaining the cephalic aspect of the main drape perpendicular to the patient’s neck. This arrangement allows unrestricted access to the patient’s head and neck. The main drape is clipped to some form of support on both sides of the patient. The support can consist of IV poles placed on each side of the patient.

Such an arrangement may not be possible in laboratories, where it interferes with radiographic equipment. Alternatively, the drape may be fixed to the C-arm or image intensifier. This solution is less than optimal; the drapes pull away whenever the C-arm or radiographic table is repositioned, increasing the risks of contamination and breaks in sterile technique. A simple, cost-effective solution consists of a length of common house wire (8/3-gauge Romex) shaped into an arc over the patient’s neck. The ends of the wire are bent at right angles to the arc and tucked under the x-ray table padding at the level of the patient’s shoulders (Fig. 21-8). The weight of the patient’s shoulders supports the wire arc. The wire positioned under the shoulder is checked with fluoroscopy to avoid interference with the radiographic field of view. The house wire is strong enough to keep its shape under the weight of the surgical drape, offering optimal patient comfort and a reliable sterile barrier. There is no interference with the C-arm, and claustrophobia is avoided. The traditional use of a Mayo stand over the patient’s face is problematic because it can cause claustrophobia, makes access to the patient’s airway difficult in an emergency, and may interfere with the x-ray equipment.

Figure 21-8 A and B, House (Romex) wire shaped to form an arch over the patient’s head is positioned under the patient’s mattress and bent to accommodate differences in patients and circumstances.

From the moment the catheterization laboratory or special studies room is cleaned, it must be treated as a surgical suite. All personnel must wear surgical clothing, hats, and masks. There should be an attempt to seal the room, limiting traffic and restricting access to personnel participating in the procedure.

Anesthesia, Sedation, and Pain Relief

Most pacemaker procedures are performed with local anesthesia and some form of sedation and pain reliever.⁴² Local anesthesia alone is inadequate for optimal patient comfort; its effect does not prevent the discomfort associated with creation of the pacemaker pocket. Therefore, the additional combination of a narcotic and sedative is recommended; use of sedation alone is frequently inadequate. The challenge to the physician in charge is to achieve patient comfort without risking oversedation or respiratory depression. If an anesthesiologist or nurse anesthetist is part of the implantation team, patient comfort is usually achieved easily and safely. In this situation, if respiratory depression occurs, the patient can easily be ventilated. When the implanting physician orders the sedation and narcotics, however, the patient must be carefully monitored by the circulating nurse. The medications should be administered slowly.

The selection and dose of local anesthetic are also important considerations. A local agent in therapeutic concentration that provides rapid onset of action and sustained duration is desirable. Local agents can be used in combination to achieve the desired effect, such as lidocaine for its rapid onset and bupivacaine for its sustained action. Also, the upper limit of total local anesthetic dose should not be exceeded. Toxic blood levels of local anesthetics can result in profound neurologic abnormalities, including obtundation and seizures. Table 21-3 lists the pharmacologic properties of common local anesthetic agents.

The selection of sedative and narcotic depends on personal preference. We use midazolam and fentanyl. The operator should become familiar with one or more sedative agents as well as an analgesic, preferably a narcotic. Many newer agents are available. The selection of a benzodiazepine in combination with a semisynthetic narcotic can achieve ideal sedation, amnesia, and analgesia. A cooperative, relaxed, and pain-free patient is fundamental to the success of the procedure and the avoidance of complications. Pentothal and nitrous oxide have been used to effect brief periods of complete sedation at times of anticipated maximum discomfort, but the use of these drugs requires the expertise of an anesthetist because temporary respiratory support is frequently needed.

The U.S. Joint Commission on Accreditation of Healthcare Organizations mandates that institutions establish a policy and protocol for patients receiving IV sedation, which would include pacemaker procedures. In essence, the protocol requires formal patient assessment before sedation. Resuscitation equipment must be present at all times in the sedation and recovery areas, and patients undergoing IV sedation must be monitored with pulse oximetry, continuous ECG rhythm monitoring, and automatic blood pressure recordings. Monitoring of the patient should continue for at least 30 minutes after the last IV sedative dose and for at least 90 minutes after intramuscular (IM) sedative administration. There are also strict discharge criteria. Table 21-4 lists common intravenous sedation drug protocols. A North American Society of Pacing and Electrophysiology (NASPE; now Heart Rhythm Society) Expert Consensus developed recommendations and specified minimum training requirements on the use of IV sedation/analgesia by nonanesthesia personnel in patients undergoing arrhythmia-specific diagnostic, therapeutic, and surgical procedures.⁴³

Antibiotic Prophylaxis and Wound Irrigation

The use of prophylactic antibiotics to reduce the incidence of postoperative wound infection in a pacemaker procedure is controversial.⁴⁴ Importantly, antibiotics are not a substitute for good infection control practices, an adequate surgical environment, and good surgical technique. The use of antibiotics in a pacemaker procedure follows the principle of prophylaxis, in which the risk for infection is low but the morbidity is high.^45–47 The selection of antibiotics is based on site-specific flora for wound infection and the spectrum, kinetics, and toxicity of the antimicrobial agent. The risk factors for infection have been well defined. The National Research Council for Wound Classification places the risk for infection from an elective procedure with primary closure at less than 2%. One important consideration is the higher risk for infection in procedures lasting longer than 2 hours.

Now more formally studied, the use of prophylactic antibiotics in the low-risk, high-morbidity group, such as patients receiving pacemakers and defibrillators, appears justified. A meta-analysis of antibiotic prophylaxis showed a significant reduction in the incidence of infection.⁴⁸ The spectrum of the antibiotic prophylaxis only needs to cover the gram-positive skin flora, primarily Staphylococcus epidermidis and S. aureus. In the case of pacemakers and cardiac procedures, the cephalosporins appear ideal (e.g., 1-2 g of cefazolin IV, pre-anesthesia). Because many institutions have a high incidence of methicillin-resistant S. aureus or S. epidermidis, vancomycin should be considered (e.g., 1 g IV slowly preoperatively). Postoperative doses are left to clinical judgment. Generally, 1 g of either drug may be given intravenously (IV) up to 8 hours postoperatively. Occasionally, the postoperative doses of cephalosporin are given orally for several days.⁴⁹ A large, prospective, randomized double-blind placebo-controlled trial (RCT) recently validated the efficacy of antibiotic prophylaxis before implantation of pacemakers and defibrillators.⁵⁰ The trial planned to enroll 1000 patients, but enrollment was terminated at 649 patients by the safety committee. The study demonstrated a significant reduction in infectious complications with antibiotic prophylaxis with 1 g of cefazolin administered before the procedure. Pretreatment with cefazolin reduced the incidence of postprocedural infection (0.64% cefazolin vs. 3.28% placebo; P = .016).

The utility of prophylactic antibiotic has now been well established. Studies have shown that a single preoperative dose of antibiotics is as effective as a 5-day course of postoperative therapy. The prophylaxis should target the anticipated organisms. With complicated or contaminated procedures, additional postoperative coverage is indicated. During prolonged procedures, antibiotics should be readministered every 3 hours. Most importantly, prophylactic antibiotics should be administered within 1 hour before incision and should not be given more than 24 hours after the procedure.^51–53

An additional strategy in the prevention of infection is topical antibiotic prophylaxis or antibiotic wound irrigation.⁵⁴ Controlled trials evaluating the benefit of antibiotic irrigations are lacking. The concept of irrigation is to provide a high concentration of antibiotic at the site of potential infection at the time of contamination. The technique has proved most efficient in the absence of established infection and uses nonabsorbable antibiotics. Historically, aminoglycosides and bacitracin combinations have been used, but regimens vary in number, type, concentration, and duration of antibiotic use. Systemic toxicity with antibiotic irrigation is a major concern. Using large volumes of irrigating solutions with systemic antibiotics can greatly exceed the therapeutic range. The superiority of irrigation over systemic antibiotic administration has never been proved, and given the potential toxicity, caution in its use is recommended. Table 21-5 lists common antibiotic irrigation protocols.

TABLE 21-5 Common Antimicrobial Irrigation Protocols

Recently, a novel antibacterial pouch (AIGISx, TyRxPharma) was developed to inhibit biofilms of S. aureus on CIEDs. It consists of a controlled–release polypropylene envelope impregnated with the antibiotics rifampin and minocycline. Its purpose is to reduce the incidence of pocket infections associated with pulse generator changes and other CIED procedures in the patient at high risk for infection; it is not recommended for all patients. An in vitro study demonstrated that the envelope significantly reduced the ability of S. aureus to form biofilms on mock CIEDs.⁵⁵ Such patients at high risk for infection include the immunocompromised patient with renal failure patients receiving oral anticoagulants, and those undergoing CIED replacement/revision procedures. Bloom et al.⁵⁶ reported on use of the antibacterial pouch in 624 consecutive CIED procedures of high-risk patients. Device implantation was successful in 621 procedures, with only three major infections. There were no deaths related to the pouch. Use of the pouch was associated with high CIED implantation success with low infection rate in a population at high risk for CIED infection. No data show that the antibiotic pouch reduces the rate of clinical infection in any population.

Despite the controversial nature of prophylactic systemic antibiotics and topical irrigation, the experience of one of the authors (PHB) at the Pacemaker and Arrhythmia Center, El Cajon, California, has been very gratifying. A protocol of intravenous antibiotics and wound irrigation has been followed at this facility since 1978. In each case, 1 g of cefazolin was given intraoperatively, followed by cefadroxil monohydrate, 500 mg, twice daily for 4 days. Previously a sponge soaked in povidone-iodine was placed in the pacemaker pocket just after pocket formation and removed at wound closure. To avoid the risk of leaving a sponge in the pocket, the pocket is flushed with povidone-iodine administered by 10-cc syringe. In more than 1500 pacemaker procedures, there have been two wound infections. A similar low incidence of infection has occurred at the other author’s (DWR) institution, University of Oklahoma College of Medicine. Since 1980, this institution’s regimen has consisted of a preoperative dose of cefazolin, 1 g IV, followed by 1 g IV for one to five more doses every 8 hours (depending on length of stay), as well as pocket irrigation with a solution of bacitracin, gentamicin, and polymyxin. Although the issue is admittedly controversial, the implanting physician needs to experience only one pacemaker infection with its many problems to become convinced that infection should be avoided at all cost.

Anatomic Approaches for Implantation

There are two basic anatomic approaches to the implantation of a permanent pacemaker.^57,58 Historically, the first is the epicardial approach, and the second the transvenous approach. The epicardial approach calls for direct application of pacemaker electrodes on the heart. This requires general anesthesia and surgical access to the epicardial surface of the heart. The transvenous approach is usually performed with local anesthesia and IV sedation. Each approach can be accomplished by several unique techniques. Currently, 95% of all pacemaker implantations are performed transvenously. The epicardial approach is generally reserved for patients who cannot undergo safe or effective pacemaker implantation by the transvenous route. The major epicardial techniques involve either applying the electrode(s) directly to a completely exposed heart or performing a limited thoracotomy through a subxiphoid incision (Fig. 21-9). A third technique places the leads by mediastinoscopy. There is even a fourth technique, which combines epicardial and endocardial lead placement. The several techniques used for the transvenous approach involve a venous surgical cutdown, percutaneous venous access, or a combination of both (Box 21-4). The pros and cons of the various approaches and techniques are reviewed here.

Figure 21-9 Location of surgical incisions for the placement of epimyocardial systems.

A thorough knowledge of the anatomic structures of the neck, upper extremities, and thorax is essential for cardiac pacing (Fig. 21-10). The precise location and orientation of the internal jugular, innominate, subclavian, and cephalic veins are important for safe venous access.^59,60 Their anatomic relations to other structures is crucial to avoiding complications.

Figure 21-10 Anatomic relationship of the vascular structures in the neck and superior mediastinum.

The venous anatomy of interest, from a cardiac pacing point of view, starts peripherally with the axillary vein.⁶⁰ This large venous structure represents the continuation of the basilic vein and starts at the lower border of the teres major tendon and latissimus dorsi muscle. The axillary vein terminates immediately beneath the clavicle at the outer border of the first rib, where it becomes the subclavian vein. The axillary vein is covered anteriorly by the pectoralis minor and pectoralis major muscles and the costocoracoid membrane. The axillary vein is anterior and medial to the axillary artery, which it partially overlaps. At the level of the coracoid process, the axillary vein is covered only by the clavicular head of the pectoralis major muscle (Fig. 21-11). At this juncture, the axillary vein receives the more superficial cephalic vein.

Figure 21-11 Detailed anatomy of the anterolateral chest demonstrating the axillary vein with the pectoralis major and pectoralis minor muscles removed.

The cephalic vein terminates in the deeper axillary vein at the level of the coracoid process beneath the pectoralis major muscle. The cephalic vein often used for pacemaker venous access is classified as a “superficial vein of the upper extremity.” This vein, which actually commences near the antecubital fossa, travels along the outer border of the biceps muscle and enters the deltopectoral groove, an anatomic structure formed by the deltoid muscle and clavicular head of the pectoralis major. The cephalic vein traverses the deltopectoral groove and superiorly pierces the costocoracoid membrane, crossing the axillary artery and terminating in the axillary vein just below the clavicle at the level of the coracoid process.

The subclavian vein is a continuation of the axillary vein. The subclavian vein extends from the outer border of the first rib to the inner end of the clavicle, where it joins with the internal jugular vein to form the brachiocephalic trunk or innominate vein. The subclavian vein is just inferior to the clavicle and subclavius muscle. The subclavian artery is located posterior and superior to the vein. These two structures are separated internally by the scalenus anticus muscle and phrenic nerve. Inferiorly, the subclavian vein is associated with a depression in the first rib and on the pleura. The brachiocephalic trunks or innominate veins are two large, venous trunks located on each side of the base of the neck. The right innominate vein is relatively short. It starts at the inner end of the clavicle and passes vertically downward to join with the left innominate vein just below the cartilage of the first rib to form the superior vena cava (SVC). The left innominate vein is larger and longer than the right, passing from left to right for approximately 2.5 inches (6 cm), where it joins with the right innominate vein to form the SVC. The left innominate vein is in the anterior and superior mediastinum.

The internal and external jugular veins have also been used for pacemaker venous access. The external jugular vein is a superficial vein of the neck that receives blood from the exterior cranium and face. This vein starts in the substance of the parotid gland, at the angle of the jaw, and runs perpendicular down the neck to the middle of the clavicle. In this course, the external jugular crosses the sternocleidomastoid muscle and runs parallel to its posterior border. At the attachment of the sternocleidomastoid to the clavicle, the external jugular vein perforates the deep fascia and terminates in the subclavian vein just anterior to the scalenus anticus muscle. The external jugular is separated from the sternocleidomastoid muscle by a layer of deep cervical fascia. Superficially, it is covered by the platysma muscle, superficial fascia, and skin. The external jugular vein can vary in size and may even be duplicated. Because of its superficial orientation, the external jugular vein is less frequently used for cardiac pacing venous access (Fig. 21-12).

Figure 21-12 Detailed anatomy of the neck demonstrating the relationship of venous anatomy to the superficial and deep structures.

The internal jugular vein is an unusual site for pacemaker venous access. Because of its larger size and deeper and more protected orientation, however, the internal jugular vein is used more frequently than the external jugular vein. The internal jugular vein starts just external to the jugular foramen at the base of the skull. It drains blood from the interior of the cranium as well as superficial parts of the head and neck. This vein is oriented vertically as it runs down the side of the neck. Superiorly, the internal jugular is lateral to the internal carotid and inferolateral to the common carotid. At the base of the neck, the internal jugular vein joins the subclavian vein to form the innominate vein. The internal jugular vein is large and lies in the cervical triangle, defined by the (1) lateral border of the omohyoid muscle, (2) inferior border of the digastric muscle, and (3) medial border of the sternocleidomastoid muscle. The superficial cervical fascia and platysma muscle cover the internal jugular vein, which is easily identified just lateral to the easily palpable external carotid artery.

From a venous access perspective, the location of the subclavian vein may vary from a normal lateral course to an extremely anterior or posterior orientation in elderly patients. Byrd⁶¹ has described the subclavian venous anatomy of two distinct deformities, both of which make venous access more difficult and hazardous. The first deformity involves a posteriorly displaced clavicle (Fig. 21-13). This is usually seen in patients with chronic lung disease and anteroposterior chest enlargement. Such patients can be identified from the presence of a horizontal deltopectoral groove and the posteriorly displaced clavicle. The second deformity is an anteriorly displaced clavicle (Fig. 21-14), which is found occasionally, especially in elderly women. In this situation, the clavicle is anteriorly bowed or actually displaced anteriorly. It is important that the implanting physician recognize such variations so as to avoid complications such as pneumothorax and hemopneumothorax when using the percutaneous approach.

Figure 21-13 Posterior displacement of clavicle.

The deltopectoral groove is in a horizontal rather than an oblique position.

(From Byrd CL: Current clinical applications of dual-chamber pacing. In Zipes DP, editor: Proceedings of a symposium. Minneapolis, 1981, Medtronic, p 71.)

Figure 21-14 Anterior displacement of clavicle.

The deltopectoral groove is nearly vertical.

(From Byrd CL: Current clinical applications of dual-chamber pacing. In Zipes DP, editor: Proceedings of a symposium. Minneapolis, 1981, Medtronic, p 71.)

It is assumed that the implanting physician is also completely familiar with the anatomy of the heart and great vessels.⁶² However, their spatial orientation is at times confusing, particularly with respect to the right atrium (RA) and right ventricle (RV). In the frontal plane, the border of the right side of the heart is formed by the RA. The border of the left side of the heart is composed of the left ventricle. Importantly, the RV is located anteriorly (Fig. 21-15) and is triangular. The apex of the RV is the generally accepted initial “target” for ventricular lead placement, although its location can vary. Its normal location, distinctly to the left of midline, depends on the rotation of the heart, which is affected by various pathologic and anatomic conditions. At times, the apex may be located directly anterior to or even to the right of midline. A lack of appreciation of these variations can lead to considerable difficulty in electrode placement.

Figure 21-15 Spatial orientation of the right ventricle as an anterior structure in relationship to the left or posterior ventricle or coronary sinus, which is also posterior.

The choice of site for pacemaker implantation is also occasionally important anatomically. This decision is typically made most appropriately on the basis of the patient’s dominant hand, occupation, recreational activities, and medical conditions. The decision should not be made according to the dominant hand of the implanting physician. However, some fundamental differences exist between the anatomy of the right and left sides, which can be frustrating when passing a pacemaker electrode. It seems to be easier for many right-handed implanters to work on the right side of the patient, and vice versa, but from a surgical point of view, catheter manipulation from the right can be a frustrating experience. When entering the central venous circulation from the left upper limb, the pacemaker electrode tracks along a smooth arc to the RV. There are generally no sharp angles or bends (Fig. 21-16, A). Conversely, when approaching from the right, the electrode is forced to negotiate a sharp angle or bend at the junction of the right subclavian and internal jugular veins, where the innominate vein is formed (Fig. 21-16, B). This acute angulation can make the manipulation of the pacemaker electrode difficult when a curved stylet is fully inserted. Another anatomic pitfall occurs when there is a persistent left SVC, making passage to the heart from the left more difficult and, if there is no right SVC, makes passage from the right impossible. These situations are considered later, in the discussion of ventricular electrode placement.

Figure 21-16 A, Smooth course of an electrode entering from the left side. B, Acute angulation of the catheter course when the lead enters the venous system from the right.

Cephalic Venous Access

The right or left cephalic vein is the most common vascular entry site for insertion of pacemaker electrodes by the cutdown technique.⁶³ The cephalic vein is located in the deltopectoral groove (Fig. 21-17), which is formed by the reflections of the medial head of the deltoid and the lateral border of the greater pectoral muscles. The groove can be precisely located by palpating the coracoid process of the scapula. The dermis along the deltopectoral groove is infiltrated with local anesthetic, encompassing the anticipated length of the incision. A vertical incision is made adjacent to and at the level of the coracoid process. It is extended for about 2 to 5 cm. Care is taken to keep the scalpel blade perpendicular to the surface of the skin. One can create smooth skin edges by making an initial single stroke that carries through the dermis to each corner of the wound. The subcutaneous tissue is infiltrated with local anesthetic along the edges of the incision. The Weitlaner retractor is applied to the edges of the wound, and the subcutaneous tissue is placed under tension. The tension is released by light strokes of the scalpel from corner to corner of the wound in the midline. As the subcutaneous tissue falls away, tension is restored by reapplication of the Weitlaner retractor. This process is continued down to the surface of the pectoral fascia. The fascia is left intact. At this level, the borders of the pectoral and deltoid muscles forming the deltopectoral groove are identified. A Metzenbaum scissors is used to dissect along the groove by separating the muscles’ fibrous attachments. The Weitlaner retractor is reapplied more deeply to retract the muscle. Gradual release of the fascial tissue between the two muscle bodies will expose the cephalic vein.

Figure 21-17 Anatomy of deltopectoral groove.

At times, the cephalic vein is diminutive or atretic and unable to accommodate a pacemaker lead. In this case, the cephalic vein can be dissected, centrally, to the axillary vein, and this larger vein catheterized. Once the vein to be catheterized is localized, it is freed of all fibrous attachments. Ligatures are applied proximally and distally (Fig. 21-18, A). The distal ligature is tied and held by a small clamp. The proximal ligature is not tied but is kept under tension with another clamp. An arbitrary entry site is chosen between the two ligatures. The anterior one half of the vein at this site is grasped with a smooth forceps, and the vein is gently lifted. A small, horizontal venotomy is made with iris scissors (Fig. 21-18, B) or a No. 11 scalpel blade. The vein is continuously supported by the forceps. The venotomy is held open by any of several means: a mosquito clamp, forceps, or vein pick. Gentle traction is applied on the distal ligature while tension is released on the proximal ligature. With the venotomy held widely open, the electrode or electrodes are inserted and advanced into the central venous circulation (Fig. 21-18, C).

Figure 21-18 A, Introduction of a lead into the cephalic vein, which is isolated and tied off distally. B, Venotomy performed with iris scissors. C, Lead inserted while venotomy is held open with a vein pick.

Subclavian Venous Access

For many years, vascular access has been achieved for many purposes through the use of the Seldinger technique. This simple approach calls for the percutaneous puncture of the vessel with a relatively long, large-bore needle; passage of a wire through the needle into the vessel; removal of the needle; and passage of a catheter or sheath over the wire into the vessel with removal of the wire. An 18-gauge, thin-walled needle 5 cm in length is typically used, although smaller needles are available. These needles come prepackaged with most introducer sets (Fig. 21-19), but an extra supply should be available. The historical problem limiting the use of this technique in cardiac pacing was the inability to remove the sheath from the pacemaker lead. The development of a peel-away sheath by Littleford solved this problem.^64–67

Figure 21-19 Prepackaged introducer set with 18-gauge needle, guidewire, and sheath with rubber dilator.

Use of the percutaneous approach requires a thorough knowledge of both normal and abnormal anatomy to avoid complications. The subclavian vein is generally the intended venous structure used for percutaneous venous access in cardiac pacing. Given the previously discussed anatomic variations, the subclavian vein puncture is typically made near the apex of the angle formed by the first rib and clavicle.⁶⁸ This defines the “subclavian window” (Fig. 21-20). At this puncture site (and after both skin infiltration with local anesthetic and a 1-cm incision at the site, which generally is 1 to 2 cm inferolateral to the point where the clavicle and first rib actually cross), the needle is aimed in a medial and cephalic direction. It is important to make the puncture with the patient in a “normal” anatomic position. The infraclavicular space or costoclavicular angle should not be artificially opened by maneuvers such as extending the arm or placing a towel roll between the scapulae. These maneuvers can open a normally closed or tight space and lead to undesirable puncture of the costoclavicular ligament or subclavius muscle, which in turn can result in lead entrapment and crush. With the patient in the normal anatomic position, access to the subclavian window is medial yet usually avoids the costoclavicular ligament. The more medial puncture and needle trajectory of this approach vastly improves the success rate and dramatically reduces the risks of pneumothorax and vascular injury compared with a more lateral approach. With this medial position, the vein is a much larger target, and the apex of the lung is more lateral. This safer approach is a departure from the conventional subclavian venous puncture, which calls for introduction of the needle in the middle third of the clavicle.

Figure 21-20 The subclavian window.

(From Barold SS, Mugica J: New perspectives in cardiac pacing. Armonk, NY, 1988, Futura, p 257.)

There are legitimate concerns that this medial approach, although safer, results later in higher complication rates and failure rates from conductor fracture and insulation damage.⁶⁹ It is postulated that the extreme medial position results in a tight fit, subjecting the lead to compressive forces and causing binding between the first rib and the clavicle. Occasionally, this binding can even crush the lead, now called the subclavian crush phenomenon. This phenomenon is more common in larger, complex leads of the in-line bipolar, coaxial design. Fortunately, the incidence of this complication is low. Fyke^70,71 first reported insulation failure of two leads placed side by side with use of the percutaneous approach through the subclavian vein, where there was a tight costoclavicular space. This issue has now been addressed thoroughly by two independent groups. Jacobs et al.⁷² analyzed a series of failed leads for the mechanism of failure, using autopsy studies to correlate the anatomic relationship of lead position to compressive forces (Fig. 21-21). These autopsy data demonstrated generation of significantly higher pressure when leads were inserted in the costoclavicular angle than with a more lateral puncture. The authors concluded that the tight costoclavicular angle should be avoided. Magney et al.⁷³ derived similar data from cadaveric studies and suggested that lead damage is caused by soft tissue entrapment by the subclavius muscle rather than bony contact. This soft tissue entrapment causes a static load on the lead at that point, and repeated flexure around the point of entrapment may be responsible for the damage.

Figure 21-21 A, Musculoskeletal anatomy of the infraclavicular space. B, Relationship of the venous structures to clavicle, first rib, and costoclavicular ligaments. C, Course of leads through the venous structures shows how the pacemaker electrode can become entrapped.

(From Jacobs DM, Fink AS, Miller RP, et al: Anatomical and morphological evaluation of pacemaker lead compression. Pacing Clin Electrophysiol 16: 434, 1993.)

Concern about subclavian crush has also been communicated by pacemaker manufacturers in company literature.^74,75 Reduction in lead diameter and perhaps modification of lead technology may be required to eliminate this problem. In the meantime, technique modification appears to be effective at reducing its occurrence. In our experience, if a pacemaker lead feels tight in the costoclavicular space, it is more susceptible to being crushed; it has become our practice at the University of Oklahoma (DWR) to remove the lead from the vein in this situation and repuncture the vein in a slightly different location with reintroduction of the lead. We believe that this practice has reduced the incidence of crush, although more substantial modifications in technique, described later, may be indicated.

Addressing this issue, along with other introducer- or percutaneous-related complications, Byrd⁷⁶ has described a “safe introducer technique.” This technique consists of a “safety zone” associated with precise conditions ensuring a safe puncture. Byrd also describes a new technique for cannulating the axillary vein if this safety zone cannot be entered. Byrd’s safety zone is defined as a region of venous access between the first rib and the clavicle, extending laterally from the sternum in an arc (Fig. 21-22, A). As a condition for puncture, the site of access must be adequate for ease of insertion to avoid friction and puncture of bone, cartilage, or tendon. With this technique, subclavian vein puncture should never be made outside the safety zone or in violation of the preceding conditions.

Figure 21-22 A, Anatomic orientation of the “safety zone” for intrathoracic subclavian vein puncture. B, Safe access to the extrathoracic portion of the subclavian vein as described by Byrd.

(A from Barold SS, Mugica J: New perspectives in cardiac pacing 2, Armonk, NY, 1991, Futura, p 108; B from Byrd CL: Recent developments in pacemaker implantation and lead retrieval. Pacing Clin Electrophysiol 16:1781, 1993.)

If the safety zone is inaccessible, or the preceding conditions are not met, an axillary vein puncture is recommended. As previously mentioned, the axillary vein is actually a continuation of the subclavian vein after it exits the superior mediastinum and crosses the first rib. The axillary vein is also frequently referred to as the extrathoracic portion of the subclavian vein (Fig. 21-23).

Figure 21-23 Anatomic relation of axillary vein to pectoralis minor muscle.

The pectoralis major muscle has been removed. Note the cephalic vein draining directly into the axillary vein at approximately the first intercostal space.

(From Belott PH et al: Unusual access sites for permanent cardiac pacing. In Barold SS, Mugica J, editors: Recent advances in pacing for the 21st century. Armonk, NY, 1998, Futura, p 139.)

Axillary Venous Access (see Box 21-4)

The axillary vein approach is actually not new. In 1987, on the basis of cadaveric studies that established reliable surface landmarks, Nichalls⁷⁷ and Taylor and Yellowlees⁷⁸ reported this approach as an alternative safe route of venous access for large, central lines. The axillary vein has a completely infraclavicular course (Fig. 21-24). The needle path must always be anterior to the thoracic cavity, avoiding risks of pneumothorax and hemothorax.

Figure 21-24 Nichalls’ landmarks for axillary venipuncture.

(From Belott PH, Byrd CL: Recent developments in pacemaker implantation and lead retrieval. In Barold SS, Mugica J, editors: New perspectives in cardiac pacing. Armonk, NY, 1991, Futura.)

The axillary vein starts medially at a point below the aspect of the clavicle where the space between the first rib and the clavicle becomes palpable. The vein extends laterally to a point about three fingerbreadths below the inferior aspect of the coracoid process. The skin is punctured along the medial border of the smaller pectoralis muscle at a point above the vein as it is defined by the surface landmarks. One punctures the axillary vein by passing the needle anterior to the first rib, maneuvering posteriorly and medially corresponding to the lateral to medial course of the axillary vein. The needle never passes between the first rib and the clavicle, but stays lateral to this juncture. Some implanters have found it useful to abduct the arm 45 degrees when using this approach.

In the technique described by Byrd, the axillary vein puncture is performed as a modification of the standard subclavian vein procedure without repositioning of the patient (Fig. 21-25; see also Fig. 21-20, B). The introducer needle is guided by fluoroscopy directly to the medial portion of the first rib. The needle is held perpendicular to, and touches, the first rib. The needle, held perpendicular to the rib, is “walked” laterally and posteriorly, touching the rib with each change of position. Once the vein is punctured, as indicated by aspiration of venous blood into the syringe, the guidewire and the introducer are inserted with use of standard technique. This approach essentially guarantees a successful and safe venipuncture without compromising the leads if the conditions for entering the safety zone are adhered to and if the first rib is touched to maintain orientation. The only complication not prevented by this approach is inadvertent puncture of the axillary artery.

Figure 21-25 Byrd’s technique for access to extrathoracic portion of subclavian vein.

Sequential needle punctures are walked posterolaterally along the first rib.

(From Belott PH, Byrd CL: Recent developments in pacemaker implantation and lead retrieval. In Barold SS, Mugica J, editors: New perspectives in cardiac pacing. Armonk, NY, 1991, Futura.)

Byrd⁷⁹ has reported success in a series of 213 consecutive cases in which the extrathoracic portion of the subclavian vein (axillary vein) was successfully cannulated as a primary approach. Magney et al.⁸⁰ subsequently reported a new approach to percutaneous subclavian venipuncture to avoid lead fracture. This technique is very similar to Byrd’s and uses extensive surface landmarks for venipuncture (Fig. 21-26). It involves puncture of the extrathoracic portion of the subclavian vein. Magney et al.⁸⁰ define the location of the axillary vein as the intersection with a line drawn between the middle of the sternal angle and the tip of the coracoid process. This is generally near the lateral border of the first rib.

Figure 21-26 Deep (A) and superficial (B) anatomic relationships of the Magney approach to subclavian venipuncture. Point M indicates the medial end of the clavicle. X defines a point on the clavicle directly above the lateral edges of the clavicular/subclavius muscle (tendon complex) (R1). V indicates the center of the subclavian vein as it crosses the first rib. The arrow indicates the center of the subclavian vein as it crosses the first rib. Ax, Axillary vein; Cp, coracoid process; St, center of the sternal angle; *, costoclavicular ligament. Arrow in B points to Magney’s ideal point for venous entry.

(From Magney JE, Staplin DH, Flynn DM, et al: A new approach to percutaneous subclavian needle puncture to avoid lead fracture or central venous catheter occlusion. Pacing Clin Electrophysiol 16:2133, 1993.)

Belott⁸¹ described blind axillary venous access using a modification of the Byrd and Magney recommendations. In this technique, the deltopectoral groove and coracoid process are primary landmarks and are palpated, and the curvature of the chest wall is noted (Fig. 21-27). An incision is made at the level of the coracoid process. It is carried medially for about 6.25 cm (2.5 inches) and is perpendicular to the deltopectoral groove (Fig. 21-28). The incision is carried to the surface of the pectoralis major muscle. The deltopectoral groove is visualized on the surface of the muscle. The needle is inserted at an angle 45 degrees to the surface of the pectoralis muscle and parallel to the deltopectoral groove and 1 to 2 cm medial (Fig. 21-29). At present, the blind venous access approach has been abandoned (PHB) for this first rib approach, because it reduces the risk of pneumothorax to zero.⁸² Critical to its success is the ability to identify the first or second rib on a radiograph. In addition, if the first rib is poorly visualized or set too far under the clavicle, one can always use the second rib in a similar fashion.

Figure 21-27 Superficial landmarks of deltopectoral groove.

Palpation of the deltopectoral groove and coracoid process.

Figure 21-28 A, Incision perpendicular to the deltopectoral groove at the level of the coracoid process. B, Close-up view of incision demonstrating the plane of the deltopectoral angle and the plane of the deltopectoral groove and pectoralis muscle.

Figure 21-29 Needle and syringe trajectory and angle with respect to the deltopectoral groove and chest wall.

To access the axillary vein using the first rib, the image intensifier is pulled over to the incision. The first rib is then identified, usually the most superior U-shaped rib (Fig. 21-30, A). The ribs seen traversing medial to lateral in an inferior direction are posterior. Identifying the first rib fluoroscopically is critical. If the operator misinterprets a posterior rib as the first rib, a percutaneous stick will result in a pneumothorax or access of undesired cardiopulmonary structures. The first step in accessing the axillary vein using the first rib is to place the 18G percutaneous needle and syringe on top of the pectoralis major muscle in the superior aspect of the incision. Using fluoroscopy, the needle tip is placed in the middle of the first rib (Fig. 21-30, B). The angle of the syringe and needle is gradually increased as the needle is advanced through the pectoralis major muscle. The foreword motion of the percutaneous needle and syringe should allow the tip of the needle to be maintained fluoroscopically over the body of the first rib. To maintain first rib orientation, a rather steep angle is generally required. The needle advancement is continued until the first rib is struck. In essence, this maneuver is attempting to pin the axillary vein to the first rib (Fig. 21-31). Once the first rib is touched, the needle and syringe are slowly withdrawn under suction until the vein is entered, as indicated by a flash of blood in the syringe. If the first pass is unsuccessful, the needle and syringe are moved medially or laterally, and the maneuver is repeated until successful. Once the vein is entered, the guidewire is passed and the sheath applied per standard technique. If the needle is advanced toward the first rib through tissue or muscle without the needle tip initially visualized fluoroscopically directly over the first rib, this shallow angle may result in the needle passing between an intercostal space. This will result in a pneumothorax. It is recommended that a figure-of-eight stitch be applied around the needle puncture for hemostasis and the retained-guidewire technique used for multiple lead placement.

Figure 21-30 A, Radiograph showing location of the first rib. Arrows point to the rib’s anterior border. B, Radiograph of needle over the first rib. The needle tip is maintained in this position as the needle and syringe are advanced. This is accomplished increasing the steepness of the needle angle.

Figure 21-31 Needle trajectory in relationship to first rib.

The superior needle is piercing the axillary vein. The needle tip is touching the first rib. The lower needle with the shallow angle runs the risk of entering the intercostal space, causing pneumothorax.

Occasionally, in a thin patient, the axillary artery can be easily palpated. This makes the axillary vein stick easy, because the percutaneous puncture can be made just medial and inferior to the palpable axillary pulse. Because it cannot always be palpated, the axillary pulse is not a reliable landmark. The axillary artery and brachial plexus are usually much deeper and more posterior structures. This simple technique, which uses basic anatomic landmarks of the deltopectoral groove and a blind venous stick, has been used successfully in 168 consecutive pacemaker and ICD procedures. There have only been three failures requiring an alternative approach. With a thorough knowledge of the regional anatomy, the physician can safely use the axillary vein as a primary site for venous access.

Access to the axillary vein may also be achieved by direct cutdown. With Metzenbaum scissors, fibers of the pectoralis major muscle are separated adjacent to the deltopectoral groove at the level of the coracoid process. This is just above the level of the superior border of the pectoralis minor. If the pectoralis major is split in this area and the fibers are gently teased apart in an axis parallel to the muscle bundle, the axillary vein can be found directly beneath the pectoralis major muscle. A purse-string stitch is applied to the axillary vein, which can then be cannulated by a direct puncture or cutdown technique. The purse-string stitch will serve for hemostasis and ultimately assists in anchoring the electrodes after positioning.

A number of techniques can facilitate access to the axillary vein. Varnagy et al.⁸³ describe a technique for isolating the cephalic and axillary veins by introduction of a radiopaque J-tipped polytetrafluoroethylene guidewire through a vein in the antecubital fossa under fluoroscopic control (Fig. 21-32). The metal guidewire is then palpated in the deltopectoral groove or identified with fluoroscopy. This guides the subsequent cutdown or puncture of the vessel with fluoroscopy. A cutdown can be performed on a vein, and the intravascular guidewire pulled out of the venotomy to allow the application of an introducer. If a percutaneous approach is used, the puncture can always be extrathoracic, using fluoroscopy to guide the needle to the guidewire. This technique offers the benefit of rapid venous access while avoiding the risk of pneumothorax associated with the percutaneous approach.

Figure 21-32 Percutaneous access to the axillary vein using a J wire introduced by means of the antecubital vein for reference.

Contrast venography, described subsequently, can also be used for axillary venous access. The venous anatomy can be observed with contrast fluoroscopy in the pectoral area and, if possible, recorded for repeat viewing. The needle trajectory and venipuncture are guided by the contrast material in the axillary vein. Laboratories with sophisticated imaging capabilities can create an image “mask” (see later). Spencer et al.^84,85 reported the use of contrast material for localizing the axillary vein in 22 consecutive patients. Similarly, Ramza et al.⁸⁶ demonstrated the safety and efficacy of using the axillary vein for placement of pacemaker and defibrillator leads when guided with contrast venography. They successfully accomplished lead placement in 49 of 50 patients using this technique.

Access to the axillary vein can also be guided by Doppler flow detection and ultrasound techniques. Fyke⁸⁷ describes use of an extrathoracic introducer insertion technique in 59 consecutive patients (total of 100 leads) with a simple Doppler flow detector. A sterile Doppler flow detector is moved along the clavicle. Once the vein is defined, the location and angulation of probe are noted, and the venipuncture is carried out (Fig. 21-33). Care is taken to avoid directing the Doppler beam beneath the clavicle. Gayle et al.⁸⁸ have developed an ultrasound technique that directly visualizes the needle puncture of the axillary vein.⁸⁹ A portable ultrasound device with sterile sleeve and needle holder are used. The ultrasound head is placed over the skin surface in the vicinity of the axillary vein. Once the vein is visualized, the puncture technique can be used. This technique has been used with considerable success for both pacing and defibrillator electrodes. There have been no reports of pneumothoraces. This technique can be carried out transcutaneously or through the incision on the surface of the pectoralis muscle (Figs. 21-34 and 21-35).

Figure 21-33 Doppler ultrasound location of the axillary vein crossing the first rib. AV, Axillary vein; CCL, costoclavicular ligament; Cl, clavicle; P, Doppler probe; R1, first rib; R2, second rib; SCM, subclavius muscle; SCV, subclavian vein.

Figure 21-34 Ultrasonic image of the axillary vein.

Figure 21-35 Ultrasound-guided puncture of the axillary vein with use of the Site-Rite device (Site Rite Ultrasound System, Salt Lake City, Utah).

In summary, the axillary vein has become a common venous access site for pacemaker and defibrillator implantations, because of concerns about subclavian crush and the requirement for insertion of multiple electrodes for dual-chamber pacing and at least one large complex electrode for transvenous defibrillation. A number of reliable techniques are available for axillary venous access (see Box 21-4). Given the recent interest in the axillary vein, it is recommended that the implanting physician become thoroughly familiar with the relevant anatomy. The interested physician must visit the anatomic laboratory to refresh and review the regional anatomy and surface landmarks. There is also some concern that lateral access of the axillary vein can result in acute bends in the lead. This can result in increased lead stress and potential for fracture or lead damage, because in its lateral aspect, the axillary vein is a much deeper structure as it transitions to the subclavian vein. It is this deeper venous access that results in acute lead angulation. This is particularly true for those who use the second rib as a landmark for axillary venous access.

For a more conventional subclavian vein approach, Lamas et al.⁹⁰ have even recommended fluoroscopic observation of the needle trajectory for achieving a successful and safe subclavian vein puncture. They initially identify the clavicle on the side of the puncture, noting its course and landmarks. The skin is entered about 2 cm inferior to the junction of the medial and lateral halves of the clavicle, aiming with fluoroscopic guidance for the caudal half of the clavicular head.

The various techniques of transvenous pacemaker lead placement—the subclavian window, the safety zone, the axillary vein puncture, or fluoroscopic guidance—have some common features. Needle orientation is always medial and cephalad, almost tangential to the chest wall. All needle probing should use a forward motion. Lateral needle probing should be avoided because it could lacerate important structures. Anatomic landmarks are defined, and the puncture is made, with rare exception, with the patient in the anatomic position. The costoclavicular angle is not artificially opened by maneuvers. Although the essence of the nonaxillary approaches is medial placement to avoid the lung, the undesirable puncture of the costoclavicular ligament should be avoided. In the obese patient, the tendency is to orient the needle more perpendicular to the chest wall in an attempt to pass between the clavicle and first rib. This perpendicular angle is to be avoided with the medial approaches because it is associated with a higher incidence of pneumothorax. In this circumstance, a more inferior skin puncture is recommended, allowing the needle to slip between the first rib and clavicle. The needle is therefore kept almost tangential to the chest wall, avoiding the lung. Some implanters bend the needle in an attempt to slip under the clavicle. We do not recommend this maneuver because it is associated with a higher incidence of pneumothorax and vascular trauma. We instead recommend that in the morbidly obese patient, the subclavian puncture be carried out after direct visualization of the pectoral muscle. This can be done only by making an initial skin incision and carrying it down to the pectoral muscle. Once the anatomic landmarks are defined, the needle is slipped between the first rib and the clavicle with a trajectory that is nearly tangential to the chest wall and directed cephalad and medial.

This last recommendation raises the question whether the skin incision should routinely be made first, with percutaneous venous access carried out through the incision, or whether an initial percutaneous venous puncture should be performed, followed by the incision. It is arguably better for one not to commit to an initial pocket-length incision and subsequent venipuncture. Doing so avoids the embarrassment of having to explain matching incisions if venous access could not be achieved through the initial incision and one is forced to move to the patient’s other side. It is difficult enough explaining multiple unsuccessful skin punctures. As an acceptable alternative, regularly used at the University of Oklahoma, a 1-cm-long stab wound can be made initially, through which the venipunctures can be accomplished. This approach allows easy incorporation of the puncture sites (especially if two separate punctures are used for a dual-chamber pacing system) into a single incision that is extended after successful venipuncture. A full incision is made to the greater pectoral fascia before one gains access to the vein.

As with axillary vein access techniques, the subclavian puncture can be facilitated by the use of contrast venography.⁹¹ It is helpful in patients with potentially difficult venous access. Venography should be considered before any puncture in which venous patency is in doubt or abnormal anatomy is suspected. As described by Higano et al.,⁹¹ a venous line is established in the arm on the side of planned pacemaker venous access. The line should be reliable and 20 gauge or larger. One must ensure that the patient does not have an allergy to radiographic contrast material. The contrast injection is performed by a nonsterile assistant. From 10 to 50 mL of contrast material (nonionic or ionic) is injected rapidly into the IV line in the forearm, followed by a saline bolus flush. The contrast medium moves slowly in the peripheral venous system and can be moved along by massage of the arm through or under the sterile drapes. The venous anatomy is observed with fluoroscopy in the pectoral area and, if possible, recorded for repeated viewing (Fig. 21-36). The needle trajectory and venipuncture are guided by the contrast material in the subclavian vein. In more sophisticated radiologic laboratories, a mask or map can be made for guidance after the contrast medium has dissipated. The process can be repeated as necessary.

Figure 21-36 Contrast venography–guided venipuncture. With contrast material, the needle is guided under fluoroscopic guidance directly to the vein.

The actual percutaneous puncture is carried out with a syringe attached to the 18-gauge needle. A common practice is to fill the syringe partially with saline. The theory behind this practice is that if a pneumothorax occurs, it will be detected by air bubbles aspirated through the saline. In addition, the saline can be used to flush out tissue plugs that may obstruct the needle and prevent aspiration. We avoid this practice because we believe that one does not need air bubbles to detect an inadvertent pneumothorax. More important, the syringe even partially filled with saline makes it difficult to differentiate between arterial and venous blood, because when blood (arterial or venous) mixes with the saline, it takes on the color of oxygenated blood. If saline is not used, which vascular structure has been entered is more readily apparent.

When proceeding with a percutaneous venipuncture, one should hold the syringe in the palm of the hand with the dorsal aspect of the hand resting on the patient. This gives support and control as the needle is advanced. With the needle held this way, tactile sensation is enhanced, and one can frequently feel the needle enter the vein. Once the vessel is entered, the guidewire is inserted, and the tip advanced to a position in the vicinity of the right atrium (Fig. 21-37). We prefer to use J-shaped or curved-tip guidewires for safety reasons. If resistance is encountered, the wire is withdrawn slightly and advanced again. If the resistance persists, the wire position is checked with fluoroscopy. If the wire just outside the tip of the needle appears coiled, it is probably extravascular. In this case, the wire and needle are removed, and a new venous puncture is carried out. Extremely rarely, one may not be able to re-enter the vein. This may be due to collapse of the vein by a resultant hematoma caused by a small tear in the vein from the misdirected guidewire. In this case, one should probably proceed to an alternative approach or site of venous access, to avoid an unnecessary waste of time and a higher risk of pneumothorax with multiple subsequent unsuccessful percutaneous punctures.

Figure 21-37 A, Once venous access is achieved, the needle is supported with one hand, and the guidewire with tip occluder is advanced with the other hand. B, Guidewire tip advanced to the middle right atrium.

(A from Belott PH: Retained guide wire introducer technique, for unlimited access to the central circulation. Clin Prog Pacing Electrophysiol 1:59, 1983.)

Occasionally, the guidewire tracks up the internal jugular vein. Changing the angle of the needle slightly to a more medial and inferior direction while the guidewire is still in the internal jugular vein, withdrawing the guidewire back into the needle, and then advancing again usually results in passage of the guidewire through the innominate vein and SVC into the right atrium. This maneuver may have to be repeated several times with varying needle angulations. Care must be exercised to avoid tearing the vein. The application of a 5-French (5F) or 6F dilator can sometimes help steer the guidewire in the right direction. In rare cases, the guidewire and needle must be removed and a new puncture site selected. The key point is that once venous access has been achieved, every effort is made to retain it.

When air is withdrawn through the needle during attempted venipunctures, suggesting lung puncture and raising the possibility of a pneumothorax, our practice is to withdraw the needle, wait to ensure a rapid-onset, large, symptomatic pneumothorax is not occurring, and then proceed with a different needle trajectory and further attempts at venipuncture. In our experience, most lung punctures occurring with forward (not lateral!) needle motion do not result in a clinically apparent (on chest radiography) pneumothorax. If a pneumothorax does develop, it may do so in this setting over a matter of hours and may not even be apparent radiographically at the end of the procedure. If a lung puncture has occurred, obtaining another upright chest radiograph 6 hours after completion of the procedure is advisable. If a pneumothorax has developed, a chest tube or catheter evacuation procedure may be necessary, although frequently, a small to moderate pneumothorax that is not expanding can be managed conservatively without evacuation.

Similarly, if an arterial puncture occurs inadvertently, our approach consists of removal of the needle and compression at the puncture site for about 5 minutes, followed by repeated venipuncture attempts with a different needle path. It is rare for such arterial punctures to result in a hemothorax, provided that no tearing of the artery has occurred (avoidance of lateral needle motion is crucial here as well). Follow-up chest radiographs are recommended 6 to 18 hours after the procedure, and postoperative hemoglobin and hematocrit measurements are suggested. The most important problem to avoid if the artery has been punctured is nonrecognition and placement of a sheath into the artery. If there is any doubt about whether the artery has been punctured, a blood sample withdrawn through the needle and subjected to oximetric analysis should clarify the situation.

Once the wire is successfully positioned in the vein, some implanters place a purse-string suture in the tissue around the point of entry of the wire into the tissue. Alternatively, a figure-of-eight stitch can be applied (Fig. 21-38). This step can be helpful later for hemostasis.⁹² Such sutures require that an incision be made beginning at the needle and extending inferiorly to the depth of the pectoral fascia.

Figure 21-38 Placement of the figure-eight stitch to enhance hemostasis.

(From Belott PH: Retained guide wire introducer technique, for unlimited access to the central circulation. Clin Prog Pacing Electrophysiol 1:59, 1983.)

Once the guidewires are in the subclavian vein, it is usually a simple procedure to advance the appropriate-sized dilator and peel-away sheath over the wire into the venous circulation. Occasionally, there is substantial resistance to dilator-sheath advancement, and repetitive dilation with progressively larger dilators is necessary. Alternatively, a 15- to 20-degree bending of the tip of the full-sized introducer may facilitate advancement over the wire. If difficulty with advancement occurs, we generally remove the sheath from the dilator and use only the dilator initially to dilate the track into the vein. This protects the rather delicate sheaths from damage. After successful advance of the dilator alone over the wire, the dilator can be withdrawn, the sheath added, and both then advanced over the wire. We have found that gentle back-pressure on the guidewire while the dilator-sheath is advanced also facilitates advancement in difficult or tortuous vessels.

After the sheath has been successfully passed over the guidewire to the vicinity of the SVC, the dilator and guidewire can be removed, and the lead advanced through the sheath. Problems can be encountered when the lead is passed through the sheath. Occasionally, in the process of introduction, the sheath buckles at a point in the venous system where there is a bend⁹³ (Fig. 21-39). This usually occurs after the removal of the dilator. It can also occur if the sheath is advanced against the lateral wall of the SVC; if a buckle occurs, the lead will not pass this point. Forcing the lead can result in damage to the cathode and insulation. This kink can usually be observed on fluoroscopy. There are several solutions to this problem. If the guidewire and dilator have both been removed, both can be replaced down the sheath. The dilator with wire inside is now functioning not only as a way to stiffen the sheath, but also as a tip occluder, and both can be passed back down the sheath. The tapered tip of the dilator will straighten the buckle. One can change the position of the buckle point by slightly advancing or retracting the sheath. The dilator is removed, but the guidewire can be retained. It is hoped that the retained guidewire will act as a stent, preventing the buckle from recurring and thus allowing the electrode to pass completely down the sheath. Another option when buckling of sheath occurs is to advance the lead to within a couple of centimeters of the buckle and then slowly withdraw the sheath, holding the lead position stationary. The sheath, including the buckle point, may occasionally be easily withdrawn over the tip of the lead, and the lead can be cautiously advanced. In this situation, it is sometimes necessary to withdraw the stylet from the tip of the lead to allow easy advancement of the lead beyond the buckle point. Inexperienced implanters should be cautious with this latter technique, however, because it may damage the distal electrodes.

Figure 21-39 Buckling of the introducer sheath prevents the passage of the electrode.

If these maneuvers fail, the guidewire and dilator are reinserted and the sheath and dilator are removed, leaving the guidewire in the vein. Tissue compression or traction is applied to the purse-string suture for hemostasis. The sheath is inspected for buckling. At this point, the implanter should consider advancing a sheath of the next larger size over the retained guidewire, because application of the same-sized sheath usually results in recurrence of the same problem. The important point is that despite this frustrating experience, one must be reluctant to relinquish the vein once it has been catheterized. Generally, the larger sheath is less likely to buckle, especially if the guidewire is retained to act as a stent. With successful electrode introduction, the sheath is briskly pulled back out of the circulation, and skin compression or traction is applied to the purse-string or figure-of-eight suture for hemostasis.

The risk of air embolization is substantial with the percutaneous approach; using the Trendelenburg position is recommended. With the shift of the pacemaker procedure to the CCL or special procedures room, however, it is often impossible to place the patient in Trendelenburg position. Consequently, the patient is at greater risk for air embolization if the percutaneous approach is used. It is most important that the implanting physician be aware of the danger and take steps necessary to avoid this potential catastrophe (Box 21-5). The physician must be aware that removal of the sheath dilator in a patient who is fasting and somewhat volume depleted can rapidly cause aspiration of large quantities of air. Because the luxury of the Trendelenburg position is unlikely to be available in the CCL, other steps must be taken. Contrary to some practices, the patient about to undergo pacemaker implantation should be kept in a euvolemic or even a relatively volume-overloaded state if there is no contraindication. Instead of IV fluids at a restricted rate, adequate hydration should be maintained. We routinely place a large, wedge sponge under the patient’s legs to enhance blood return and increase central venous pressure.

An assessment of the state of hydration can be carried out during the procedure. With the sheath in the central venous circulation, careful withdrawal of the dilator from the sheath can allow the state of hydration and venous pressure to be observed: After the dilator is withdrawn in the hydrated patient with adequate venous pressure, there is continuous blood flow out of the sheath despite the cycle of respiration. In the dehydrated patient, withdrawal of the dilator results in little or no blood flow. The blood meniscus is barely visible. More important, on inspiration, the blood meniscus is observed to move substantially inward. If this is seen, the dilator can be rapidly advanced back into the sheath; alternatively, the sheath can be pinched and additional precautions taken to avoid air embolization. If a wedge has not been placed under the patient’s legs, this can be done now and is frequently helpful. Also, at this point, it is most important to have the cooperation of the patient. If sleeping, the patient should be aroused. The patient should be coached to reduce the depth of respirations and avoid the sudden, large inspiration that can result in the aspiration of a lethal volume of air into the vein. At the same time, IV fluid administration is increased to enhance hydration. Having the patient hold the breath after maximal inspiration offers the greatest latitude in time, because the patient will have to exhale before inhaling, thereby causing negative intrathoracic pressure and aspiration of air into the vein. This gives the implanter time to insert the lead. Pinching of the sheath with the lead going through it to avoid air embolization is ineffective and gives a false sense of security. A peel-away sheath with a hemostasis valve would be useful. In the patient who is substantially sedated or uncooperative, adequate hydration and elevation of the lower extremities are the only solutions. Careful planning of the lead insertion procedure also helps. Expeditious lead insertion is important. For example, positioning the electrodes with the sheath in situ is unwise, because it may result in air embolism or unnecessary blood loss.

Once the lead has been inserted, the introducer should be rapidly withdrawn. The practice of peeling away the sheath while part of it is in an intravascular location should be avoided; doing so is a waste of time and increases the risk for air embolization and blood loss. In this regard, the actual peeling away of the sheath is not even a necessity at this point as long as it is completely extravascular. It can be peeled away later at one’s convenience. In fact, the tabs of the unpeeled sheath can be used to pin the lead to the drapes during threshold testing, preventing inadvertent dislodgement of the lead onto the floor. With the sheath withdrawn completely from the circulation, hemostasis is achieved by applying tension to the purse-string or figure-of-eight suture or by applying skin compression over the entry site.

A variation of the introducer technique involves retaining the guidewire. Instead of being removed together with the dilator, the guidewire is left in place so that the lead is passed through the sheath alongside it. The sheath is subsequently removed and peeled away (Fig. 21-40). Occasionally, the size of the electrode and the sheath precludes the passage of the lead alongside the guidewire. In this case, the guidewire is removed, the lead passed down the sheath, and the guidewire reinserted behind the electrode. This maneuver succeeds because it is the electrode that will not pass alongside the guidewire, whereas the lead body is thinner and leaves enough room in the sheath to accommodate the guidewire. Certain leads (especially those with bipolar electrodes) and sheath combinations are too tight to allow passage of both the electrode and guidewire. In this case, a larger sheath can be used.

Figure 21-40 A, Guidewire with dilator removed remains in the sheath. The lead has been inserted and advanced (inset) alongside the guidewire. B, Both the guidewire and the lead are advanced to the vicinity of the middle right atrium. Additional introducers can be advanced over this retained guidewire to place additional leads.

(A from Belott PH: Retained guide wire introducer technique, for unlimited access to the central circulation. Clin Prog Pacing Electrophysiol 1:59, 1983.)

When the guidewire is reintroduced, the tip occluder is not used because it can wind up in the central circulation fairly easily. Reusing the dilator as a tip occluder during reinsertion of the guidewire works well. The retained guidewire may provide unlimited venous access and the ability to exchange or introduce additional electrodes by simply applying another sheath set to the guidewire. The retained guidewire should be held to the drape with a clamp to avoid inadvertent dislodgement. The retained guidewire can serve as a ground for unipolar threshold analysis instead of a grounding plate. It can also be used as an intracardiac lead for recording of the atrial electrogram (to confirm atrial capture) or as an electrode for emergency pacing. We routinely retain an intravascular guidewire in both single-chamber and dual-chamber procedures until a satisfactory lead position is obtained.

Occasionally, difficulty may be encountered with the standard-length sheath. Venous tortuosity, obstruction, and anomalies may preclude the advancement of the lead to the right side of the heart. This problem is usually solved by advancing a 24-cm-long sheath over the guidewire directly to the right atrium. This is also advisable when an extraction has been done during the procedure because of the weakening of the venous wall. An appropriate length .035-inch guidewire is recommended. It is important that the guidewire be placed well distal to the problem area. Most long sheaths are prepackaged with a long guidewire. If an exchange is required, it is critical not to lose venous access. The original, short .035-inch guidewire should be retained, and a standard 6F sheath advanced over it. The dilator is removed and a long .035-inch guidewire passed down the 6F sheath alongside the shorter guidewire. The 6F sheath is removed, the short guidewire retained, and the long sheath passed over the long guidewire.

Methods of Dual-Chamber Venous Access

The percutaneous approach is particularly useful in dual-chamber pacing. It has eliminated the earlier dilemma of needing to introduce two leads into a vein exposed by cutdown that may barely accommodate a single lead, with the resultant need for a second venous access site. Box 21-6 lists the options for dual-chamber venous access. For dual-chamber pacing, at least four methods that involve the percutaneous approach are described here. The first three can be used with any of the previously described percutaneous approaches.

Retained-Guidewire Technique

The retained-guidewire technique can be used alone as a method for the introduction of two leads or can be incorporated into any of the other techniques for the introduction of two leads.^97,98 One of the authors (PHB) uses this technique alone, preferentially for dual-lead introductions, and the other (DWR) uses it as backup in combination with the two separate puncture techniques described previously. This approach is most desirable because it provides unlimited access to the central circulation. The implanter using this technique can easily add and exchange leads, an important advantage in dual-chamber pacing, in which the initially chosen atrial lead is occasionally unacceptable for a given anatomic situation. Less frequently, it is also helpful to be able to exchange ventricular leads. When using the retained-guidewire technique for dual-chamber implantation, one usually positions the ventricular electrode first, a practical and safe step. The ventricular electrode can be more easily stabilized and is less susceptible to dislodgement from positioning of the second electrode. One can then stabilize the ventricular electrode by leaving the stylet pulled back in the lead in the vicinity of the lower right atrium (Fig. 21-41). A stitch should be placed proximally around the lead and suture sleeve and secured about 1 to 2 cm from the puncture site in the subcutaneous tissue on the surface of the pectoral muscle.

Figure 21-41 Ventricular lead has been placed first. The guidewire has been retained, and the lead stylet is positioned in the lower right atrium for stability.

After ventricular electrode stabilization, a second sheath can be advanced over the retained guidewire. The atrial electrode is introduced, positioned, tested, and secured. Alternatively, the retained-guidewire technique can be employed to introduce both leads into the SVC, right atrium, or inferior vena cava (IVC) areas before positioning either electrode. This procedure may reduce risk of dislodgement of the initially positioned electrode caused by introduction of the second sheath. Regardless of variation, the guidewire is removed only after all leads have been placed and tied down (Fig. 21-42). A purse-string or figure-of-eight suture can be tied loosely to achieve hemostasis around the puncture site.

Figure 21-42 A, Ventricular electrode and retained guidewire are demonstrated in the main drawing. The inset demonstrates the ventricular lead anchored by suture around its suture sleeve and the second sheath advancing over the retained guidewire. A hemostat on the figure-eight suture maintains hemostasis. B, The atrial and ventricular electrodes have been positioned, yet the guidewire is still retained.

(A from Barold SS, Mugica J: New perspectives in cardiac pacing 2. Armonk, NY, 1991, Futura, p 110.)

Sheath Set Technique with Cutdown Approach

Ong et al.⁹⁹ described a modified cephalic vein guidewire technique for the introduction of one or more electrodes. The Ong-Barold technique appears to be a safe and reasonable alternative to the percutaneous subclavian vein introducer technique.¹⁰⁰ It is particularly recommended for the inexperienced implanter. It is also recommended for use in patients at high risk of complications with the percutaneous approach, as well as when the percutaneous approach is anticipated to be difficult if not impossible.

This technique requires an initial cutdown to the cephalic vein as previously described. For a single-lead introduction, the size of the vein is irrelevant. All that is necessary is the introduction of the guidewire, which is accomplished with needle puncture under direct visualization. The cephalic vein is sacrificed because it seems to invaginate into the subclavian vein with advancement of the sheath set over the guidewire (Fig. 21-43). Hemostasis is achieved with pressure or the application of a figure-of-eight stitch. Despite the sacrifice of the cephalic vein, no venous complications have been reported. When two leads are required, the retained-guidewire technique and sheath set technique can be used in this approach.

Figure 21-43 Cephalic vein guidewire technique uses the guidewire as access to the vein for one or more electrodes. The distal connection of the cephalic vein is sacrificed (Ong-Barold technique).

(From Barold SS, Mugica J, editors: New perspectives in cardiac pacing 2. Armonk, NY, 1991, Futura, p 112.)