Conduction System Pacing With Defibrillator Therapy in a Patient With Heart Failure and Ventricular Arrhythmias After...

Heart failure with reduced ejection fraction (HFrEF) complicated by malignant ventricular arrhythmias remains a major therapeutic challenge, particularly in patients following complex mitral valve surgery. Conventional right ventricular pacing may aggravate ventricular dyssynchrony and further impair systolic function. Conduction system pacing (CSP) has emerged as a physiologic pacing strategy that directly activates the native His-Purkinje system, most commonly through His bundle pacing or left bundle branch area pacing (LBBAP), allowing near-normal ventricular activation. We report the case of a 70-year-old patient who developed severe heart failure, postoperative bradyarrhythmia, and an extremely high burden of ventricular arrhythmias following urgent mitral valve replacement. Despite pharmacological therapy and unsuccessful catheter ablation, electrical instability persisted. An implantable cardioverter-defibrillator (ICD) incorporating CSP using LBBAP was successfully implanted. Baseline QRS duration prior to pacing was 183 ms, whereas paced QRS duration after LBBAP implantation was 165 ms, consistent with near-physiologic ventricular activation. ECG documentation before and after device implantation demonstrated marked QRS narrowing and substantial suppression of ventricular ectopy after CSP-ICD implantation. Early post-implant monitoring demonstrated a marked reduction in ventricular ectopy and effective physiologic pacing. During 24 months of follow-up, pacing parameters remained stable, and no ventricular arrhythmias requiring ICD therapy were observed. This case demonstrates the feasibility of combining CSP with ICD therapy in selected patients early after mitral valve surgery. These findings are hypothesis-generating and require confirmation in prospective studies and larger clinical registries to define the broader clinical role and long-term durability of this strategy.