1. Paroxysmal Atrial Fibrillation in Patients Undergoing Cardiac Resynchronization Therapy

Published on 26/02/2015 by admin

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Last modified 22/04/2025

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History

The patient has had a known cardiomyopathy for 3 years. She had coronary artery disease, with implantation of a bare metal stent (BMS) in the proximal circumflex artery in 2006. The left ventricular ejection fraction was 32% at the last visit to the cardiologist. The patient reported a rhythm disorder, but an electrocardiogram (ECG) has not been performed. She had peripheral artery disease class IIb, with a percutaneous transluminal angioplasty of the femoral artery on the left side in 2007.

Comments

The etiology of cardiomyopathy was unknown. She had cytomegalovirus-related hepatitis in the history, a myocardial biopsy revealed no active inflammation and no bacterial or viral burden, and magnetic resonance imaging did not show signs of inflammation or other structural heart disease.

Current Medications

The patient’s current medications are acetylsalicylate 100 mg/day, enalapril 5 mg/day, metoprolol succinate 95 mg/day, spironolactone 25 mg/day, torasemide 5 mg/day, and atorvastatin 20 mg/day.

Comments

The medication dosage for congestive heart failure was reduced by the cardiologist because of recurrent hypotensive episodes.

Current Symptoms

In June 2008, the patient was admitted to the hospital because of recurrent chest pain unrelated to exercise. In addition, she reported shortness of breath during minimal physical efforts.

Physical Examination

Laboratory Data

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FIGURE 1-1 12 Lead ECG at admission showing sinus rhythm with a heart rate of 68 bpm and LBBB.

Comments

No relevant abnormalities were reported in the laboratory results. The myocardial markers remained normal in following tests.

Electrocardiogram

Findings

The ECG recorded a sinus rhythm, heart rate of 68 bpm, left axis deviation, left bundle branch block (LBBB), PQ interval 160 ms, QRS 160 ms, and QT 480 ms (Figure 1-1).

Comments

The ECG identified complete LBBB, with QRS greater than 150 ms, which had been described previously.
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FIGURE 1-2 Chest radiograph at admission.

Chest Radiograph

Findings

Radiography findings were no infiltrates, no congestion, no pleural effusion, normal heart/thorax ratio, and normal heart size. A small calcified, circular formation was seen in the lower left lobe, consistent with a granuloma (Figure 1-2).

Comments

The chest radiograph was normal.

Echocardiogram

Findings

The patient’s left atrial diameter (LAD) was 35 mm, left ventricular end-diastolic diameter (LVEDD) was 62 mm, and left ventricular end-systolic diameter (LVESD) was 54 mm. She had a severely reduced left ventricular ejection fraction (30%), global hypokinesia of the left ventricle, akinesia of posterior wall, septal-to-posterior wall motion delay of 140 ms, aortic preejection time of 150 ms, moderate mitral regurgitation, slight aortic and tricuspid regurgitation, and no pericardial effusion, The inferior vena cava (IVC) and hepatic veins were not dilated (Figure 1-3).

Comments

Highly reduced left ventricular function with significant dyssynchrony was found, with no relevant signs of right heart failure.

Catheterization

Hemodynamics

Hemodynamic monitoring found highly reduced left ventricular function at 28%, moderate mitral regurgitation, no aortic stenosis, left ventricular end-systolic pressure of 128 mm Hg, left ventricular end-diastolic pressure of 20 mm Hg, pulmonary capillary wedge pressure of 34 mm Hg, pulmonary artery pressure of 64/26/44 mm Hg, right ventricular pressure of 60/0/9 mm Hg, right atrial pressure of 6 mm Hg, and cardiac output of 2.8 L/min.
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FIGURE 1-3 Echocardiography with an apical four-chamber view showing a severe dilatation of the left ventricle, highly reduced left ventricular function, and signs of dyssynchrony.

Findings

The left main artery, the left anterior descending artery, and the right coronary artery showed no significant stenosis. A nonsignificant in-stent restenosis of the circumflex artery was found (Figure 1-4).

Comments

Coronary angiography revealed coronary disease in one vessel, without significant stenosis; severely reduced left ventricular function; and pulmonary hypertension.

Focused Clinical Questions and Discussion Points

Question

What therapy options are available?

Discussion

The medical therapy of heart failure in this patient could not be intensified because of recurrent hypotensive episodes. No reversible reason for the reduced left ventricular function could be found. Based on the chronic, severely reduced left ventricular function (≤35%) under best possible medical treatment, the patient had an indication for implantable cardioverter-defibrillator for primary prevention of sudden cardiac death. In addition, because therapy for heart failure could not be intensified and the patient had an LBBB of more than 150 ms in New York Heart Association (NYHA) class II, she qualified for cardiac resynchronization therapy (CRT) according to the European guidelines.1 The documented dyssynchrony on echocardiography is not part of the guidelines but supports the indication for the resynchronization therapy.

Final Diagnosis

The final diagnosis was dilated cardiomyopathy with severe reduction of left ventricular function, NYHA III, LBBB, and coronary artery disease (single-vessel disease), with no need of intervention.
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FIGURE 1-4 Coronary angiography of left (A) and right (B) coronary artery in a right anterior oblique 30-degree view (A) and a left anterior oblique 60-degree cranial 30-degree view (B).

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FIGURE 1-5 12-Lead electrocardiogram after implantation of a cardiac resynchronization therapy–implantable cardioverter-defibrillator device in sinus rhythm.

Plan of Action

The treatment plan consisted of resynchronization therapy for heart failure and primary prevention of sudden cardiac death by implantation of a CRT-ICD device.

Intervention

The planned intervention was implantation of a CRT defibrillator device (the CRT-D system) with remote monitoring.

Postimplant Electrocardiogram

Findings

The postimplant ECG demonstrated atrial pacing and sequential atrio-biventricular pacing at a heart rate of 70 bpm, PQ interval of 110 ms, QRS of 115 ms, and QT of 470 ms (Figure 1-5).

Comments

The ECG identified paced rhythm with biventricular stimulation and significant reduction of QRS width.
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FIGURE 1-6 Chest radiograph after implantation of a CRT-ICD device showing the device, a bipolar atrial lead, a dual-coil right ventricular lead, and a bipolar left ventricular lead in a lateral branch of the great cardiac vein.

Postimplant Chest Radiograph

Findings

The postimplant radiogram showed no infiltrates, no congestion, no pleural effusion, normal heart/thorax ratio, and a heart of normal size. A left-pectoral ICD with three leads—one in the right atrium, one in the apical right ventricle, and one in the lateral coronary sinus—was placed. The chest x-ray showed on the left side and ICD and 3 leads—one in the apex of the right ventricle, and one on the lateral wall of the left ventricle. A known small calcified, circular formation, consistent with a granuloma, was noted in the lower left lobe of the lung (Figure 1-6).

Comments

The postimplant chest radiograph was normal, with normal ICD findings and ICD lead positions.

Echocardiogram (8 Weeks After Implantation)

Findings

The 8-week echocardiogram showed left atrial diameter of 36 mm, LVEDD of 54 mm, LVESD of 45 mm, moderately reduced left ventricular ejection fraction (32%), global hypokinesia of the left ventricle, septal-to-posterior wall motion delay of 80 ms, aortic preejection time of 105 ms, moderate mitral regurgitation, slight aortic and tricuspid regurgitation, right ventricular systolic pressure of 42 mm Hg, and no pericardial effusion, The IVC and hepatic veins were not dilated (Figure 1-7).
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FIGURE 1-7 Echocardiography with apical four-chamber view 8 weeks after implantation with reduced left ventricular end-diastolic and end-systolic and slightly improved ejection fraction.

Comments

The echocardiogram showed remarkable reduction of left ventricular diameters and improvement of mechanical dyssynchrony. The left ventricular ejection fraction was moderately reduced, there was no sign of mechanical dyssynchrony, and there was no sign of right heart congestion.

Outcome

A few days after implantation the patient noticed remarkable improvement of exercise tolerance. She was discharged 2 days after implantation of the CRT-D system.

Course

Three months after implantation of the CRT-D, the patient developed paroxysmal atrial fibrillation with recurrent cardiac decompensation because of an intermittent loss of ventricular capture. Antiarrhythmic therapy of amiodarone 200 mg daily was initiated, as well as oral anticoagulation therapy with phenoprocoumon, based on a CHADS-VASC score of 3.
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FIGURE 1-8 Intracardiac electrogram (EGM) of the atrial fibrillation episode via remote monitoring. A, Atrial EGM; Ars, atrial sense in refractory period; AS, atrial sense; LV, left ventricular EGM; LVS, left ventricular sense; RV, right ventricular EGM; VT1, right ventricular sense in VT1-zone; Zeit, time in seconds. After shock (40J) sinusrhythm was reestablished.

Twelve months after implantation, the patient experienced four ICD shocks. Investigation revealed episodes of atrial fibrillation to be the cause for inappropriate ICD intervention.

Findings

Recording of arrhythmia episodes by home monitoring with intracardiac electrogram documented atrial fibrillation with fast AV conduction, thus resulting in the detection of rapid ventricular rhythm. The episode terminated after six ineffective antitachycardia pacing therapies and two shocks. Sinus rhythm was reestablished at the end of the episode (Figure 1-8).

Comments

As a result of tachyarrhythmic episodes of atrial fibrillation, the patient experienced several inappropriate ICD interventions, even while on antiarrhythmic therapy with amiodarone.

Focused Clinical Questions and Discussion Points

Question

What therapy options apart from the medical treatment are available?

Discussion

In patients with recurrent episodes of atrial fibrillation despite antiarrhythmic drug treatment, catheter-based ablation for complete electrical isolation of the pulmonary veins is another treatment option,4 as implemented in the latest guidelines5 for atrial fibrillation therapy. In contrast to application in patients with chronic persistent atrial fibrillation, AV node ablation is not a recommended treatment strategy in patients with paroxysmal atrial fibrillation. First, the absence of the hemodynamic effect of the physiologic atrial contraction can result in deterioration of the heart failure. Second, after AV node ablation, patients depend on the rate response function of the device, which does not sufficiently replicate physiologic sinus node function and will lead to worse exercise tolerance.

Question

When is the best moment to perform the pulmonary vein isolation in these patients?

Discussion

As could be seen in the current case, atrial fibrillation in patients with CRT-D devices may cause severe problems by two mechanisms. Rapidly conducted atrial fibrillation can lead to worsening of heart failure in patients who are CRT responders by loss of biventricular stimulation.3 Furthermore, it can result in inadequate ICD therapies, which can be dangerous and traumatic to the patient and are of prognostic relevance.2,6 Therefore early pulmonary vein isolation should be considered even after onset of atrial fibrillation. In addition remote monitoring is a very useful feature and should be recommended for early detection of atrial fibrillation in those patients.

Plan of Action

As a result of ineffective antiarrhythmic drug-based treatment, pulmonary vein isolation was indicated.

Intervention

After three-dimensional reconstruction of the left atrium, pulmonary vein isolation was performed by circumferential radiofrequency catheter–based ablation. Electrical isolation was assessed based on spiral mapping catheter recordings (Figure 1-9).
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FIGURE 1-9 Posterior-anterior view of a three-dimensional CARTO reconstruction of the left atrium and circumferential ablation lines around the ipsilateral pulmonary veins.

Outcome

The patient remained in stable sinus rhythm. The symptoms of heart failure were reduced, resulting in much better exercise tolerance (NYHA I). Echocardiographic findings remained stable.

Selected References

1. Calkins H., Kuck K.H., Cappato R. et al. 2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design—a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Heart Rhythm. 2012;9:632–696.

2. Dickstein K., Vardas P.E., Auricchio A. et al. ESC Committee for Practice Guidelines: 2010 focused update of ESC guidelines on device therapy in heart failure: an update of the 2008 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure and the 2007 ESC guidelines for cardiac and resynchronization therapy—developed with the special contribution of the Heart Failure Association and the European Heart Rhythm Association. Europace. 2010;12:1526–1536.

3. Ouyang F., Bänsch D., Ernst S. et al. Complete isolation of the left atrium surrounding the pulmonary veins: new insights from the double-lasso technique in paroxysmal atrial fibrillation. Circulation. 2004;110:2090–2096.

4. Poole J.E., Johnson G.W., Hellkamp A.S. et al. Prognostic importance of defibrillator shocks in patients with heart failure. N Engl J Med. 2008;359:1009–1017.

5. Santini M., Gasparini M., Landolina M. et al. Device-detected atrial tachyarrhythmias predict adverse outcome in real-world patients with implantable biventricular defibrillators. J Am Coll Cardiol. 2011;7:167–172.

6. Wilton S.B., Leung A.A., Ghali W.A. et al. Outcomes of cardiac resynchronization therapy in patients with versus those without atrial fibrillation: a systematic review and meta-analysis. Heart Rhythm. 2011;8:1088–1094.

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