History
A 58-year-old male office worker with a long-standing history of cardiomyopathy, likely after an episode of viral myocarditis 20 years previously, sought treatment for worsening shortness of breath and functional deterioration. The patient was mildly obese and not in acute respiratory distress. He had a dual-chamber pacing system because of intermittent heart block and symptomatic sinus bradycardia while on medical therapy.
Because of ventricular dysfunction with a left ventricular ejection fraction (LVEF) of 28%, an implantable cardioverter-defibrillator (ICD) was recommended. The patient also had symptomatic heart failure (New York Heart Association [class III]) despite optimal medical therapy and a left bundle branch block with QRS duration of 148 ms. Cardiac resynchronization therapy (CRT) also was recommended.
He was taken to the procedure room at his local facility for upgrade to a CRT defibrillator (CRT-D) system. However, because of inability to place the left ventricular lead, the procedure was abandoned and the patient was referred for consideration of an epicardial system or to reattempt endocardial left ventricular lead and CRT-D placement. The operative note from the outside facility mentioned difficult subclavian venous access and inability to pass a wire beyond approximately 2 cm into the coronary sinus.
Past medical history is significant for intermittent atrial fibrillation, associated with mild symptoms and managed with rate control and anticoagulation.
Current Medications
The patient was taking lisinopril 10 mg twice daily, carvedilol 25 mg three times daily, and digoxin 0.125 mg once daily.
Physical Examination
Hospital and Procedural Course
After discussing the options of reattempting left ventricular lead placement, surgical epicardial lead placement, and assessment for appropriateness of left ventricular assist device or cardiac transplantation, it was decided to make another attempt at placing the coronary sinus lead before considering the other options. Another attempt at a transvenous approach was favored because of the benefits it offered over epicardial pacing, including lower surgical trauma, potentially more stable pacing electrical thresholds, and greater lead stability.6
The patient was brought in the fasting state to the procedure room. An axillary vein puncture was done with contrast venography, and a temporary pacing lead was placed because the patient was pacemaker dependent. The coronary sinus was cannulated without difficulty and balloon venography performed.
Venography findings are shown in Figure 11-1. As noted in the operative report from the referring institution, a wire would not pass beyond approximately 2 cm into the coronary sinus.
Focused Clinical Questions and Discussion Points
Question
What is the likely cause of difficulty in advancing into the coronary venous system in this patient?
Discussion
Venography demonstrated a prominent Vieussens valve.2 The Vieussens valve is a normal anatomic variant and is an intravenous valve located at the junction of the coronary sinus and the great cardiac vein. This is typically the site of takeoff for the posterolateral ventricular vein and the oblique vein of the atrium (vein of Marshall). Studies have shown that a nearly occlusive Vieussens value, as found in this patient, can prevent progression of catheters and guide wires and complicate a cardiovascular interventional procedure.4 Therefore when various wires were passed into the coronary sinus, they would typically not advance beyond the valve and curve back into the main body of the coronary sinus.
Question
What are other potential reasons a wire will not pass freely into the branches of the coronary venous system?
Discussion
Once the coronary sinus has been cannulated, it may be extraordinarily difficult in certain patients to advance into the coronary venous system, particularly to the lateral free wall of the left ventricle. Potential reasons for this include coronary vein stenosis, intraprocedural coronary artery dissection, coronary vein dissection, and postsurgical or ablative therapy–related vein occlusion. In cases in which the target vein is obstructed and no alternative vessels exist, balloon dilation or stenting may be necessary for successful lead implantation. Although the frequency of coronary vein stenosis is reported to be about 2.4% in one study, balloon angioplasty proved to be an effective method when used in combination with careful maneuvering of guide wires and leads for nearly all the patients.5
FIGURE 11-2
Sharp angles at which veins enter the coronary sinus can further interfere with the successful advancement of guide wires and lead into distal regions of the coronary venous system.8
Figure 11-2 shows venography from another patient in whom abrupt termination of the coronary sinus just distal to a posterolateral vein is noted. This patient did have prior mitral valve repair along with coronary artery bypass surgery.
FIGURE 11-3
Paradoxically, a very large coronary venous system also can make passing a wire into the ventricular veins difficult.
Figure 11-3 shows a large aneurysm in the coronary sinus with prominent posterior venous branches (arrow). Although the coronary sinus may be easy to cannulate in such patients, presumably because of prominent flow back into the right atrium, advancing a wire without coiling it back in the large aneurysm or venous system may be difficult.
Question
What options are available for the operator caring for a patient where there is inability to pass a wire to the distal ventricular venous system and lateral wall, such as in our patient with a prominent Vieussens valve?
Discussion
The previously mentioned causes of difficulty in advancing into the lateral venous system and great cardiac vein (i.e., dissection, stenosis, and Vieussens valve) typically spare the coronary sinus ostium and proximal segment of this vein. Because the middle cardiac vein (MCV) or posterior interventricular vein arises very proximally—often immediately distal to the ostium—cannulating the MCV and advancing the lead through the collateral branch of the MCV to the lateral left ventricular wall can be an effective option to consider in such patients.7 The primary branch of this vein courses along the posterior intraventricular groove and drains into the coronary sinus close to the right atrial orifice.6
How does one cannulate the MCV? Because of the proximity of the ostium of the MCV to the coronary sinus, technical difficulties arise in cannulating the MCV.
Figure 11-4 shows a useful maneuver that implanters should be familiar with for cannulating the MCV. Typically, counterclockwise torque on a preformed sheath placed from the subclavian venous system is required to enter the coronary sinus. However, continued counterclockwise torque will take the tip of the sheath toward the atrial rather than the ventricular vein. Thus the operator will need to gently withdraw the sheath back toward the ostium while placing clockwise torque on the sheath. In a stepwise manner, a wire is advanced to gently probe for the ostium of the MCV as this maneuver is employed. As the sheath is pulled back with clockwise torque just before falling out of the coronary sinus itself, the wire will advance into the MCV. Here it is sometimes useful to pass either a second wire or deflectable catheter to firmly gain access to the MCV. The sheath then can be pulled back to the right atrium to create a straight line between the sheath and the access of the MCV, and then the sheath is advanced, subselecting the MCV.
Intervention
Once subselecting access is obtained, the deflectable catheter, if used, can be removed and a lead advanced over the wire 
(see Video 11-1). The MCV drains the inferior aspect of the posterior left ventricle; the posterior vein provides a more direct access to the lateral region of the left ventricle. Nonetheless, these distinct venous systems exhibit a high occurrence of anastomoses, resulting in an interconnected venous system near the posterolateral wall of the left ventricle.1 Thus it is useful to recognize these collaterals between the middle cardiac and posterior venous system to the lateral wall. This can be done with occlusion venography in the body of the coronary vein, coronary sinus, or subselective angiography of the MCV (Figure 11-5).
(see Video 11-1). The MCV drains the inferior aspect of the posterior left ventricle; the posterior vein provides a more direct access to the lateral region of the left ventricle. Nonetheless, these distinct venous systems exhibit a high occurrence of anastomoses, resulting in an interconnected venous system near the posterolateral wall of the left ventricle.1 Thus it is useful to recognize these collaterals between the middle cardiac and posterior venous system to the lateral wall. This can be done with occlusion venography in the body of the coronary vein, coronary sinus, or subselective angiography of the MCV (Figure 11-5).Effective cardiac resynchronization therapy changes the sequence of ventricular activation, to improve the cardiac efficiency measured in terms of LVEF (Figure 11-6). The left ventricular lead ideally should be at a maximum distance from the right ventricular lead to enhance the effects of biventricular pacing. Pacing the site that is most delayed also can be an operational strategy to reduce dyssynchrony and decrease the QRS duration. It is also important that a pacing lead in the coronary vein does not stimulate the phrenic nerve, because this can cause painful stimulation of the diaphragm.9 In this patient, the lead was advanced through such a collateral vein to the posterolateral wall of the left ventricle, an excellent pacing vector between the ICD lead and the lateral left ventricular lead pacing site obtained. The previous pacing lead was extracted, and the patient had symptomatic improvement and mild improvement in ventricular function (ejection fraction, 32%).
FIGURE 11-4
FIGURE 11-5
FIGURE 11-6
MCV pacing has proved useful in avoiding phrenic nerve stimulation in similar case studies. In a patient with class III to IV heart failure, a left ventricular pacing lead was placed in the posterolateral coronary sinus branch but biventricular pacing was unsuccessful because of phrenic nerve stimulation. Cannulation of the MCV and placement of a pacing lead in an optimal apical posterolateral position can be acheived, albeit with difficulty. A follow-up examination at 8 months revealed excellent pacing (<1 V, 0.5 ms), with considerable improvement in LVEF. The patient was able to avoid surgical trauma from the open thoracotomy necessary for epicardial lead placement.
Focused Clinical Questions and Discussion Points
Question
Because the MCV is located posteriorly in the intraventricular groove and adjacent to the right ventricle, how does CRT with the left ventricular lead placed in the MCV benefit some patients?
Discussion
Figure 11-7 shows an inferior view of the autopsied heart and the course of the MCV. In most patients, beneficial left ventricular pacing therapy can be obtained despite the use of the MCV because lateral venous branches of this vein exist but drain the lateral wall of the left ventricle. These veins are analogous to the posterolateral branches of the coronary arterial system arising from the right coronary artery or the posterior descending artery. In these patients, placing a lead on the left ventricular free wall is equivalent to using, for example, a lateral vein or branch of an anterolateral vein. In other words, the pacing site is identical despite using a completely different branch of the coronary venous system to enter the ventricular veins—it is where you go that matters, not how you get there. For some patients, however, it is more difficult to understand why MCV pacing is beneficial. In these patients, as shown in the autopsied heart, there is a paucity of lateral branches and the lead is placed in the body of the MCV itself. No clear reason explains why these patients sometimes benefit, but possibilities include the following:
1. The epicardial surface myocardial fibers from the posterior wall are arranged in a radial fashion perpendicular to the long axis of the heart, whereas the endocardial fibers tend to be arranged along the long axis of the heart.7 Thus even though a right ventricular apical lead and an MCV main lead may appear fairly close to each other radiographically, because of the differences in fiber orientation, the epicardial MCV lead will excite the lateral wall of the left ventricle sooner than will a right ventricular endocardial apical lead.
2. In some patients, standard pacing sites on the left ventricular free wall laterally or anterolaterally may not be the ideal site because of the location of the right ventricular pacing lead.
FIGURE 11-7
For example, as shown in Figures 11-8 and 11-9, the right ventricular lead has been placed in the high intraventricular septum quite anteriorly. Thus it is possible in these patients that biventricular stimulation from a site on the left ventricular high lateral wall would not be very dissimilar to the right ventricular lead site, as well.
FIGURE 11-8
FIGURE 11-9
FIGURE 11-10
Note in the 12-lead electrocardiogram obtained of this patient under biventricular pacing that although lead I shows a negative deflection (activation of the lateral wall), the QRS is wide, and a left bundle branch block pattern is seen (Figure 11-10). It is possible that such patients with right ventricular leads placed anteriorly and relatively leftward may benefit by a more posteriorly placed lead, such as through a posterior ventricular vein or MCV.
Outcome
MCV pacing with placement of the lead in a lateral branch to the lateral left ventricular wall was successfully done despite an occlusive Vieussens valve being present. The patient had significant symptomatic improvement and modest improvement in LVEF and continues to do well almost 2 years from the interventional procedure.
Selected References
1. Anderson S.E., Lahm R., Iaizzo P.A. The coronary vascular system and associated medical devices. In: Iaizzo P.A., ed. Handbook of cardiac anatomy, physiology, and devices. Totowa, NJ: Humana; 2005:109–124.
2. Asirvatham S.J. Anatomy of the coronary sinus. In: Yu C.M., Hayes D.L., Auricchio A., eds. Cardiac resynchronization therapy. Malden: Blackwell Futura; 2008:211–238.
3. Bogaert J. Cardiac function. In: Bogaert J., Dymarkowski S., Taylor A.M., Muthurangu V., eds. Clinical cardiac MRI. Berlin: Springer-Verlag; 2012:109–166.
4. Corcoran S.J., Lawrence C., McGuire M.A. The valve of Vieussens: an important cause of difficulty in advancing catheters into the cardiac veins. J Cardiovasc Electrophysiol. 1999;10:804–808.
5. Hansky B., Lamp B., Minami K. et al. Coronary vein balloon angioplasty for left ventricular pacemaker lead implantation. J Am Coll Cardiol. 2002;40:2144–2149.
6. Hansky B., Schulte-Eistrup S., Vogt J. et al. Lead selection and implantation technique for biventricular pacing. Eur Heart J Suppl. 2004;6:D112–D116.
7. Lachman N., Syed F.F., Habib A. et al. Correlative anatomy for the electrophysiologist. II. Cardiac ganglia, phrenic nerve, coronary venous system. J Cardiovasc Electrophysiol. 2011;22:104–110.
8. Leon A.R., Delurgio D.B., Mera F. Practical approach to implanting left ventricular pacing leads for cardiac resynchronization. J Cardiovasc Electrophysiol. 2005;16:100–105.
9. Manolis A.S., Kappos K., Koulouris S. et al. Middle cardiac vein pacing avoids phrenic nerve stimulation, offers optimal resynchronization and obviates surgery for epicardial lead placement. Hosp Chron. 2007;2:44–45.
