Predictors of Non-Response to Left Bundle Branch Area Pacing in Heart Failure With Reduced Ejection Fraction: A Multi-Center Cohort Study

Heart failure that has a lower ejection fraction (HFrEF) is a major cause of morbidity and mortality in the world. Left bundle branch area pacing (LBBAP) has become a viable option compared to conventional cardiac resynchronization therapy (CRT) to patients with conduction system abnormalities, including left bundle block (LBBB). Yet, there is a group of patients that are not responsive to LBBAP. Predictors of non-response identification is the key to maximizing patient selection and therapy outcomes.This multicenter cohort study was conducted in patients with HFrEF (LVEF 35 % or less) and who had LBBAP implantation. Baseline clinical, electrophysiological and imaging data were taken. Response was considered as an absolute improvement in left ventricular ejection fraction (LVEF) 5% and decrease in left ventricular end-systolic volume (LVESV) 15% 6 months. The predictors of non-response were found using multivariate logistic regression.:Sixty percent of the patients were responders and 30 percent were non-responders at 6-month follow-up. Ischemic heart disease (OR 2.3, p = 0.010), LVEDD > 60 mm (OR 3.2, p = 0.001), QRS duration > 170 ms (OR 2.1, p = 0.022) and presence of myocardial scar (OR 1.8, p = 0.047) were significant predictors of non-response. LVEF and LVESV improved greatly in the responders and did not improve in non-respondents.:LBBAP is useful in the treatment of most patients with HFrEF, although non-response is more frequent in patients with ischemic heart disease, increased LVEDD, longer QRS, and myocardial scarring. These are the factors that should be taken into consideration when choosing the candidates to be recruited in LBBAP, and other strategies might be required in the case of patients at high risk.