Left bundle branch area pacing dramatically reduced device-related complications and matched clinical outcomes when compared with biventricular pacing, according to the first randomized head-to-head trial contrasting the two. The LECART Trial, presented at European Heart Rhythm Association (EHRA) 2026, examined biventricular pacing (BiV) — standard method of delivering cardiac resynchronization therapy (CRT) — with the newer left bundle branch area pacing (LBBAP).

In standard CRT, leads are placed on the surface of the heart to force the ventricles to beat together. LBBAP involves advancing a lead into the heart’s septum to directly stimulate the native conduction system, producing a more natural pattern of activation.

The challenge in BiV has always been how to reach the left ventricle safely. Traditional approaches pace it indirectly from the outside via the coronary veins, whereas newer techniques like LBBAP access the left-sided conduction system from within the septum — without entering the chamber itself.

Until now, randomized data comparing the two strategies have been lacking, with most prior evidence coming from observational studies. 

LECART Trial Data

The trial included 168 patients at 11 medical centers in Belgium. Participants had a mean age of 69 years, and 33% were women. Participants had heart failure with reduced ejection fraction (left ventricular ejection fraction < 40%), left bundle branch block, and a widened QRS duration (≥ 130 ms), consistent with guideline-based indications for CRT. Sixty-seven percent of patients had New York Heart Association class II heart failure; 77.5% were receiving at least three out of four heart failure medications recommended by the European Society of Cardiology.

Participants were randomized to LBBAP or BiV pacing and followed for 1 year. The primary endpoint was a composite of death, heart failure hospitalization, device complications requiring reintervention, or failure to deliver effective therapy.

Lead investigator Jean-Benoît le Polain de Waroux, MD, PhD, said the study design made this trial distinct from previous research. He said the LECART trial, in addition to traditional endpoints, incorporated two clinically relevant outcomes into the primary composite endpoint: the failure to implant the assigned CRT modality and the need for surgical re-intervention within the first year after implantation.

“In the absence of alternative CRT strategies, we believe that the latter endpoint may have been overlooked in previous CRT trials,” said le Polain de Waroux, a cardiologist and electrophysiologist at AZ Sint-Jan Hospital in Bruges, Belgium.

At 1 year, a primary outcome event occurred in 25% of patients in the BiV group and 13% of those in the LBBAP group (hazard ratio, 2.14; 95% CI, 1.01-4.51), representing an approximately 50% lower relative risk with LB.

LBBAP More Streamlined

Device-related complications requiring reintervention occurred in 15% of patients in the BiV group compared with about 1%-3% of those in the LBBAP group. Complications in the BiV group included lead dislodgement, fracture, loss of capture, and right ventricular perforation.

Procedure times were also shorter with LBBAP — roughly 76 minutes vs 90-98 minutes. QRS narrowing was consistently greater with LBBAP across follow-up, suggesting it restores ventricular electrical timing more effectively than conventional BiV pacing.

Importantly, the difference was driven largely by device-related complications, with no significant differences in death, heart failure hospitalization, or overall clinical improvement between groups.

Elena Arbelo, MD, PhD, MSc, a cardiologist at Hospital Clínic de Barcelona in Barcelona, Spain, called the findings encouraging but believes LBBAP is not yet a credible substitute for biventricular CRT.

“The follow-up was relatively short, the apparent benefit was driven mainly by fewer reinterventions, and the study was not really powered to draw strong conclusions on each individual component in isolation, particularly the harder clinical endpoints,” said Arbelo, who was not involved in the study.

Le Polain de Waroux reported having no relevant financial disclosures. Arbelo reported having speaking engagements with Boston Scientific and Bristol Myers Squibb, receiving and consulting fees for Bristol Myers Squibb, Cytokinetics, and Medtronic.

Lois Anzelowitz Levine is a lifestyle and medical writer in Dallas.