BiV indicates biventricular; arrhythmias; LV, left ventricular; CRT, cardiac resynchronization therapy; B-LEFT, Biventricular Versus Left Univentricular Pacing With ICD Back-Up in Heart Failure Patients; DECREASE HF, a randomized trial comparing simultaneous biventricular pacing, sequential biventricular pacing, and left ventricular pacing; and BELIEVE, Bi vs Left Ventricular Pacing: An International Pilot Evaluation on Heart Failure Patients With Ventricular Arrhythmias.