Reduced ventricular volumes and improved systolic function with cardiac resynchronization therapy: a randomized trial comparing simultaneous biventricular pacing, sequential biventricular pacing, and left ventricular pacing.

Background: Cardiac resynchronization therapy has emerged as an important therapy for advanced systolic heart failure. Among available cardiac resynchronization therapy pacing modes that restore ventricular synchrony, it is uncertain whether simultaneous biventricular (BiV), sequential BiV, or left ventricular (LV) pacing is superior. The Device Evaluation of CONTAK RENEWAL 2 and EASYTRAK 2: Assessment of Safety and Effectiveness in Heart Failure (DECREASE-HF) trial is the first randomized trial comparing these 3 cardiac resynchronization therapy modalities.
Methods and Results: The DECREASE-HF Trial is a multicenter trial in which 306 patients with New York Heart Association class III or IV heart failure, an LV ejection fraction < or = 35%, and a QRS duration > or = 150 ms were randomized to simultaneous BiV, sequential BiV, or LV pacing. LV volumes and systolic and diastolic function were assessed with echocardiography at baseline, 3 months, and 6 months. All groups had a significant reduction in LV end-systolic and end-diastolic dimensions (P<0.001). The simultaneous BiV pacing group had the greatest reduction in LV end-systolic dimension (P=0.007). Stroke volume (P<0.001) and LV ejection fraction (P<0.001) improved in all groups with no difference across groups.
Conclusions: Compared with LV pacing, simultaneous BiV pacing was associated with a trend toward greater improvement in LV size. There is little difference between simultaneous BiV pacing and sequential BiV pacing as programmed in this trial.