Biventricular pacing, with multiple leads connected to a dual-chamber biventricular pacemaker placed in the atrium and the ventricle, has been shown to provide short-term improvement in hemodynamics and systolic left ventricular (LV) function in patients with end-stage heart failure. Molhoek and associates studied the sustained clinical benefit and long-term effects of biventricular pacing in patients with heart failure.

Patients with end-stage heart failure, New York Heart Association (NYHA) functional class III or IV, and an LV ejection fraction of less than 35 percent received a biventricular pacemaker alone or with a defibrillator, when indicated. Patients with varied causes of LV dysfunction were included in the study. Patients were evaluated at the outpatient clinic at baseline and in person at three and six months; follow-up was performed by chart review, telephone contact, and outpatient visits for up to two years.

Among the 40 patients included in the study, the mean NYHA score improved from 3.3 at baseline to 2.1 at three months, and the score was maintained at six months. Quality-of-life scores tested with the Minnesota Living with Heart Failure questionnaire improved significantly within three months and were maintained at six months. The six-minute hall-walk test also improved by an average of 51 percent at three months, and the improvement was maintained at six months. The LV ejection fraction improved significantly at six months. Hospitalization days decreased significantly after pacemaker implantation, and the total mean follow-up was 11.2 months.

The authors conclude that because of remaining concern about the possibly harmful effect of increased cardiac energy expenditure on long-term mortality, as noted when long-term positive inotropic agents are administered to heart failure patients, further long-term studies are needed.