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Cardiac resynchronization improves functioning and reduces deaths for certain heart failure patients

Congestive heart failure is a debilitating condition that affects nearly 5 million individuals in the United States. Implanting biventricular pacemakers to resynchronize the ventricular contraction to improve ejection fraction (fraction of blood ejected from the ventricle) and relaxation of the left ventricle improves outcomes of heart failure in certain patients and could be cost effective when used in certain patient groups. These are the findings of the following two studies that were supported in part by the Agency for Healthcare Research and Quality (contract 290-02-0023) and conducted by AHRQ's University of Alberta Evidence-based Practice Center, Edmonton, Alberta, Canada.

McAlister, F.A., Ezekowitz, J.A., Wiebe, N., and others (2004). "Systematic review: Cardiac resynchronization in patients with symptomatic heart failure." Annals of Internal Medicine 141, pp. 381-390.

This systematic review of the literature included studies, reports, and conference proceedings from 1980 to 2004 focused on cardiac resynchronization via implanted biventricular pacemakers in patients with symptomatic heart failure. The nine trials selected for efficacy review involved 3,216 patients who had reduced ejection fraction and prolonged QRS duration on the electrocardiogram. Also, 85 percent had New York Heart Association (NYHA) class III symptoms (markedly limited physical activity, with slight activity causing fatigue, shortness of breath, or angina) or class IV symptoms (discomfort with any physical activity, with some symptoms even at rest).

Cardiac resynchronization therapy improved ejection fraction by .035, quality of life (a mean reduction of 7.6 points in score on the Minnesota Living with Heart Failure questionnaire), and function (58 percent vs. 37 percent of patients improved by at least 1 NYHA class). Heart failure hospitalizations were reduced by 32 percent, with benefits most marked in patients with NYHA class III or IV symptoms at baseline (35 percent reduction). All-cause mortality was reduced by 21 percent, driven largely by a 40 percent reduction in death from progressive heart failure.

Biventricular pacemaker implant success rate was 90 percent in 19 studies of safety, with 0.4 percent of patients dying during implantation. Over a median 6-month followup, implant leads dislodged in 9 percent of patients, and mechanical malfunctions occurred in 7 percent of patients. Since few patients in these trials had bradyarrhythmias or atrial fibrillation, the benefit of cardiac resynchronization in such patients is uncertain.

Nichol, G., Kaul, P., Huszti, E., and Bridges, J.F. (2004). "Cost-effectiveness of cardiac resynchronization therapy in patients with symptomatic heart failure." Annals of Internal Medicine 141, pp. 343-351.

This is the first published economic evaluation of the long-term costs and effects of cardiac resynchronization therapy via biventricular pacemaker implant compared with medical therapy in patients with heart failure. The authors developed a model based on data from their systematic review of studies on the topic and health-related quality-of-life and cost data from publicly available survey data. Based on the model, medical therapy saved a median of 2.64 quality-adjusted life years (QALYs) at a median lifetime cost of $34,400. Cardiac resynchronization therapy was associated with a median incremental cost of $107,800 per additional QALY saved. Although these costs are in the general range of other commonly used medical interventions, the authors caution that the estimates depend strongly on their assumptions about mortality and hospitalization rates after cardiac resynchronization.

The experience of these patients and providers may not be applicable to other settings, since only selected patients and experienced physicians participated in the randomized trials of the effectiveness of cardiac resynchronization. The procedure should not be considered in heart failure patients with coexisting conditions that shorten life expectancy. Also, these findings should be reevaluated when more is known about the likelihood of long-term complications of resynchronization.

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