Efficacy of upgrading to left bundle branch pacing in patients with heart failure after right ventricular pacing

Background: Chronic right ventricular (RV) pacing is associated with an increased incidence of heart failure and mortality. Left bundle branch (LBB) pacing could produce near-physiological electrical activation and mechanical synchrony. We aimed to report the effects of upgrading to LBB pacing in heart failure patients after chronic RV pacing. Methods: The indications included pacing-induced cardiomyopathy (PICM) in Group 1 and heart failure after RV pacing with left ventricular ejection fraction (LVEF) >= 50% in Group 2. LBB pacing was achieved by penetrating the pacing lead to the subendocardium of left-sided interventricular septum through the venous access. Left ventricular activation time (LVAT) was measured from the pacing stimulus to the ascending peak of lead V5 or V6. All patients underwent clinical and echocardiographic evaluations before and after upgrading. Results: Totally 27 patients (13 in Group 1 and 14 in Group 2) were consecutively enrolled. The mean follow-up time after upgrade was 10.4 +/- 6.1 months. Paced QRS duration was significantly shortened from 174.1 +/- 15.8 milliseconds to 116.6 +/- 11.7 milliseconds (p < .0001). The mean LVAT was 83.2 +/- 11.7 milliseconds. LVEF increased from 40.3 +/- 5.2% before upgrading to 48.1 +/- 9.5% at follow-up in patients with PICM. Serum N-terminal probrain natriuretic peptide levels decreased and New York Heart Association classification improved in both groups. No upgrade-related complications were observed. Conclusions: Upgrading to LBB pacing was feasible and effective with improved cardiac function in heart failure patients with both reduced and preserved LVEF after RV pacing.