The most important development for left bundle branch block (LBBB) is a shift in how we pace the heart. Conduction system pacing — specifically left bundle branch area pacing (LBBAP) — captures the native conduction system rather than pacing the myocardium directly, producing more physiological activation. In cohort studies, LBBAP has substantially improved left ventricular ejection fraction (for example, from around 33% to 55% over a year) and narrowed the QRS. Head-to-head against conventional biventricular pacing (cardiac resynchronization therapy, CRT), randomized data show LBBAP yields greater improvements in ejection fraction and reverse remodeling in patients with LBBB and nonischemic cardiomyopathy, and observational data suggest fewer heart-failure hospitalizations and deaths. Meanwhile, the long-term value of resynchronization itself remains well established: CRT with a defibrillator reduces all-cause mortality in patients with LBBB (as shown in the long-term MADIT-CRT follow-up). Conduction system pacing is increasingly favored as an alternative or complement to biventricular CRT in appropriate patients.
Further reading: cardiac implantable electronic devices review (Al-Khatib, NEJM 2024); MADIT-CRT long-term survival (Goldenberg et al., NEJM 2014); LBBAP versus biventricular pacing randomized data (LBBP-RESYNC).