A randomized comparison of triple-site versus dual-site ventricular stimulation in patients with congestive heart failure.

OBJECTIVES: We compared the effects of triple-site versus dual-site biventricular stimulation in candidates for cardiac resynchronization therapy.

BACKGROUND: Conventional biventricular stimulation with a single right ventricular (RV) and a single left ventricular (LV) lead is associated with persistence of cardiac dyssynchrony in up to 30% of patients.

METHODS: This multicenter, single-blind, crossover study enrolled 40 patients (mean age 70 +/- 9 years) with moderate-to-severe heart failure despite optimal drug treatment, a mean LV ejection fraction of 26 +/- 11%, and permanent atrial fibrillation requiring cardiac pacing for slow ventricular rate. A cardiac resynchronization therapy device connected to 1 RV and 2 LV leads, inserted in 2 separate coronary sinus tributaries, was successfully implanted in 34 patients. After 3 months of biventricular stimulation, the patients were randomly assigned to stimulation for 3 months with either 1 RV and 2 LV leads (3-V) or to conventional stimulation with 1 RV and 1 LV lead (2-V), then crossed over for 3 months to the alternate configuration. The primary study end point was quality of ventricular resynchronization (Z ratio). Secondary end points included reverse LV remodeling, quality of life, distance covered during 6-min hall walk, and procedure-related morbidity and mortality. Data from the 6- and 9-month visits were combined to compare end points associated with 2-V versus 3-V.

RESULTS: Data eligible for protocol-defined analyses were available in 26 patients. No significant difference in Z ratio, quality of life, and 6-min hall walk was observed between 2-V and 3-V. However, a significantly higher LV ejection fraction (27 +/- 11% vs. 35 +/- 11%; p = 0.001) and smaller LV end-systolic volume (157 +/- 69 cm(3) vs. 134 +/- 75 cm(3); p = 0.02) and diameter (57 +/- 12 mm vs. 54 +/- 10 mm; p = 0.02) were observed with 3-V than with 2-V. There was a single minor procedure-related complication.

CONCLUSIONS: Cardiac resynchronization therapy with 1 RV and 2 LV leads was safe and associated with significantly more LV reverse remodeling than conventional biventricular stimulation.