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Device Therapy Improves Outcomes in Heart-Failure Patients

Data from two trials shed light on the benefits of biventricular pacing and implantable defibrillator therapy.

Heart-failure patients are at high risk for both sudden death and rehospitalization for heart failure. In two randomized trials, researchers explored how these outcomes were affected by cardiac resynchronization therapy (CRT) with biventricular pacemakers and by implantable cardioverter-defibrillator (ICD) therapy.

In one trial, 1520 patients with NYHA class III-IV heart failure (either ischemic or nonischemic), ejection fractions 35%, and electrocardiographically measured QRS complexes 120 msec were randomized to receive optimal medical therapy (OMT) alone, OMT plus CRT (with biventricular pacing), or OMT plus CRT plus ICD therapy. At 1 year, the composite rate of death and rehospitalization for any cause was significantly lower with CRT or with CRT plus ICD therapy (56% in each group) than with OMT alone (68%). The all-cause mortality rate was 19% with OMT alone, which was significantly higher than with CRT plus ICD therapy (12%) and marginally higher than with CRT without ICD therapy (15%).

In the other trial, 458 patients with nonischemic dilated cardiomyopathy (ejection fraction <36%), premature ventricular complexes or nonsustained ventricular tachycardia, and histories of symptomatic heart failure received standard medical therapy alone or such therapy plus ICD therapy. During a mean follow-up of 29 months, the number of deaths in the ICD group was marginally lower than in the standard-therapy group (28 vs. 40; hazard ratio, 0.65; P=0.08). However, the number of arrhythmia-related deaths was significantly lower (3 vs. 14, respectively; HR, 0.20) in the ICD group.

Comment: In the larger trial, patients with severe heart failure and ventricular dyssynchrony benefited overall from biventricular pacing and realized a specific advantage in all-cause mortality with complementary ICD therapy. In the smaller trial, ICD therapy showed a significant advantage over medical therapy for preventing arrhythmia-related death but not all-cause mortality, in part because of relatively low mortality in the medically treated group. Editorialists highlight remaining questions, such as which CRT recipients also should get ICDs and which are the optimal pacing sites in the left ventricle. Device therapy clearly has the potential to aid some high-risk heart-failure patients -- the trick will be figuring out precisely which patients and how to pay for therapy.

— Kirsten E. Fleischmann, MD, MPH

Published in Journal Watch General Medicine July 16, 2004

Citation(s):

Bristow MR et al. Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med 2004 May 20; 350:2140-50.

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• Medline abstract (Free)

Kadish A et al. Prophylactic defibrillator implantation in patients with nonischemic dilated cardiomyopathy. N Engl J Med 2004 May 20; 350:2151-8.

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• Medline abstract (Free)

Rogers JG and Cain ME. Electromechanical associations. N Engl J Med 2004 May 20; 350:2193-5.

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• Medline abstract (Free)