We read with great interest the report by Lin et al.,1 demonstrating reversal of left bundle branch block (LBBB) and recovery of left ventricular (LV) dysfunction following left bundle branch area pacing (LBBAP) in a patient with presumed LBBB-induced cardiomyopathy. This case highlights the therapeutic potential of conduction system pacing as a physiologic resynchronization strategy.

However, the need for the implantable cardioverter-defibrillator (ICD) component warrants further discussion. The patient had newly reduced LV ejection fraction (38%) with previously normal function and experienced rapid reverse remodeling (LVEF 57% at three months) after LBBAP, consistent with a reversible, dyssynchrony-mediated cardiomyopathy.1

Current evidence supports a cautious approach to primary prevention ICD implantation in such settings. The 2021 European Society of Cardiology heart failure guidelines recommend reassessment after optimization of therapy,2 while the DANISH trial questions the mortality benefit in non-ischemic cardiomyopathy.3 The EHRA consensus paper further emphasizes individualized decision-making in conduction system pacing.4,5

Mechanistically, LBBB-induced cardiomyopathy reflects electrical dyssynchrony rather than fixed scar; thus, restoration of conduction with LBBAP may reduce arrhythmogenic substrate by improving electrical synchrony and repolarization homogeneity, potentially lowering arrhythmic risk.6 Importantly, cardiac magnetic resonance imaging could have refined risk stratification: absence of late gadolinium enhancement would support a low-risk, reversible phenotype, whereas fibrosis would favor ICD consideration.7

In this context, CRT-P or LBBAP without a defibrillator may have been a reasonable initial strategy, with ICD implantation deferred based on recovery and imaging findings. In LBBB-induced cardiomyopathy, early physiologic resynchronization combined with imaging-guided risk stratification may allow safe deferral of ICD implantation in selected patients.