All Patients With Heart Failure and Intraventricular Conduction Defect or Dyssynchrony Should Not Receive Cardiac Resynchronization Therapy

Abstract

C ase Presentation: J.S., a 72-year-old man, was diagnosed with heart failure 5 years ago. Before that, he had suffered a large anterior myocardial infarction and had undergone successful coronary artery bypass grafting surgery. An internal cardioverter-defibrillator (ICD) was implanted 3 years ago. He was hospitalized briefly for decompensated heart failure 9 months ago, and his medical regimen was intensified at that time. He subsequently resumed his usual activities, which included daily walks of up to several hundred yards around his company's construction work site and 2 to 3 rounds of golf weekly. His only symptoms were fatigue after 36 holes of golf and shortness of breath while walking uphill rapidly. Medications included 0.125 mg digoxin, 40 mg furosemide, and target doses of an angiotensin-converting enzyme inhibitor, a ␤-blocker, and warfarin. An ECG demonstrated atrial fibrillation with a controlled ventricular response. The QRS duration was 130 ms with a left bundle-branch block pattern. On echocardiogram, the left ventricular (LV) ejection fraction (EF) was 23% with anterior wall akinesis; the LV internal diastolic dimension was 83 mm; and there was trace mitral regurgitation. Cardiac resynchronization therapy (CRT) was recommended. Placement of an LV pacing lead and "upgrading" his ICD to an ICD/biventricular pacemaker was performed uneventfully. Response by Abraham p 2691Shortly after the procedure, he experienced recurrent ventricular tachyarrhythmias, and his ICD, which had not discharged since implantation, delivered 4 shocks over a 24-hour period to terminate episodes of ventricular fibrillation. There was no evidence of acute myocardial infarction, worsening heart failure, or a pericardial effusion. The ventricular arrhythmias were responsive to intravenous amiodarone. After 7 days, he was discharged on oral amiodarone in addition to his other medications. Over the next several weeks, he had only 1 episode of ventricular tachycardia terminated by pacing. During this period, however, he complained of fatigue, malaise, and gastrointestinal symptoms. Amiodarone was discontinued, and over the next several weeks, these symptoms resolved. There were no further ventricular arrhythmias, and J.S. resumed his activities at work and on the

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“…It is uncertain at present whether patients with atrial fi brillation or right bundle-branch block benefi t from CRT. (9,10) Studies show that patients with a combination of right bundle branch block and pulmonary hypertension do not benefi t from CRT.…”

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