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A randomized double-blind comparison of biventricular versus left ventricular stimulation for cardiac resynchronization therapy: The Biventricular versus Left Univentricular Pacing with ICD Back-up in Heart Failure Patients (B-LEFT HF) trial

Giuseppe Boriani, MD, PhD,a Wolfgang Kranig, MD,b Erwan Donal, MD, PhD,c Leonardo Calo, MD,d Michela Casella, MD,e Nicolas Delarche, MD,f Ignacio Fernandez Lozano, MD,g Gerardo Ansalone, MD,h Mauro Biffi, MD,a Eric Boulogne, MSc,i and Christophe Leclercq, MD, PhDc for the B-LEFT HF study group
Bologna and Rome, Italy; Bad Rothenfelde, Germany; Rennes and Pau, France; Madrid, Spain; and Zaventem, Belgium

Background Biventricular (BiV) stimulation is the preferred means of delivering cardiac resynchronization therapy (CRT), although left ventricular (LV)–only stimulation might be as safe and effective. B-LEFT HF is a prospective, multicenter, randomized, double-blind study aimed to examine whether LV-only is noninferior to BiV pacing regarding clinical and echocardiographic responses.

Methods B-LEFT HF randomly assigned 176 CRT-D recipients, in New York Heart Association class III or IV, with an LV ejection fraction ≤35% and QRS ≥130 milliseconds, to a BiV (n = 90) versus LV (n = 86) stimulation group. Clinical status and echocardiograms were analyzed at baseline and 6 months after CRT-D implant to test the noninferiority of LV-only compared with BiV stimulation.

Results The proportion of responders was in line with current literature on CRT, with improvement in heart failure composite score in 76.2% and 74.7% of patients in BiV and LV groups, respectively. Comparing LV versus BiV pacing, the small differences in response rates and corresponding 95% CI indicated that LV pacing was noninferior to BiV pacing for a series of response criteria (combination of improvement in New York Heart Association and reverse remodeling, improvement in heart failure composite score, reduction in LV end-systolic volume of at least 10%), both at intention-to-treat and at per-protocol analysis.

Conclusions Left ventricular–only pacing is noninferior to BiV pacing in a 6-month follow-up with regard to clinical and echocardiographic responses. Left ventricular pacing may be considered as a clinical alternative option to BiV pacing. (Am Heart J 2010;0:1-7.e1.)