People with atrioventricular (AV) block—a type of heart rhythm disorder—had lower incidences of death, hospitalisation for heart failure and pacing-induced cardiomyopathy when the pacemaker technique implemented was left bundle branch pacing (LBBP) rather than right ventricular pacing, according to independent, preliminary, late-breaking science presented at the 2026 American Heart Association (AHA) Scientific Sessions (7–9 November, Chicago, USA).
The standard treatment for AV block is a pacemaker that sends electrical signals to the heart’s right ventricle, with the current standard-of-care technique being right ventricular pacing, which has been routinely used for decades to prevent bradycardia and cardiac arrest in these patients. Although it may keep the heart from beating too slowly, pacing only the right side can make the heart’s lower chambers beat out of sync—and, over time, this imbalance may cause pacing-induced cardiomyopathy and contribute to heart failure in some people.
LBBP is a newer pacing technique that sends the pacemaker signal into part of the heart’s own electrical pathway, mimicking the heart’s natural electrical activation sequence to help the lower chambers squeeze in a more coordinated pattern.
“Not all pacing options are the same, and people who need a pacemaker to keep their heart beating properly should talk with their healthcare team about which pacing approach is appropriate for their condition,” said study author Jiangang Zou (Nanjing Medical University, Nanjing, China). “Our findings show that LBBP helped the heart beat in a more natural way and was linked to fewer serious heart-related events than the standard pacing approach of right ventricular pacing.”
The international, multicentre OptimPacing trial tracked nearly 700 men and women with AV block being treated with a pacemaker over a five-year period, from June 2021 to January 2025. The trial was conducted at 17 centres in mainland China, Hong Kong, the UK, Poland, and the USA.
In the trial, LBBP was associated with a 59% lower risk of death, heart failure hospitalisation or cardiomyopathy compared with outcomes in the right ventricular pacing group. At four years, an estimated 8.5% of participants in the LBBP group had died, were hospitalised for heart failure or developed pacing-induced cardiomyopathy, compared with 19.2% in the right ventricular pacing group. Additionally, no participants in the LBBP group developed pacing-induced cardiomyopathy, compared with 11.7% in the right ventricular pacing group, while heart failure hospitalisation rates were 1.5% versus 2.9%, respectively.
An independent data monitoring committee reviewed the results of the planned interim analysis after a median three-year follow up, which found that the primary outcome of mortality, heart failure hospitalisation and pacing-induced cardiomyopathy occurred in 8.5% of patients receiving LBBP compared with 19.2% receiving right ventricular pacing. The committee recommended ending the trial early because LBBP met the study’s pre-established threshold for superiority.
“We expected that the group with LBBP would do better than the group with right ventricular pacing. However, the difference between the two groups was greater than we expected. This study shows that LBBP should be the first choice for patients with heart block who need a pacemaker,” Zou stated.
The OptimPacing investigators also note that their study had several limitations. The trial’s early termination could potentially lead to an overestimation of the benefits of LBBP and reduce the precision of estimates. Furthermore, most participants started with normal ejection fraction, meaning the findings may not apply to people with already reduced heart function. All LBBP procedures used the same type of lead, so it is not known whether the results apply to other pacing tools.
“Future research is needed to refine which pacing technique is most appropriate for which patients, compare different pacing approaches that follow the heart’s natural electrical system, and examine long‑term safety and cost‑effectiveness to help inform updates to clinical guidelines,” Zou added.
