Left ventricular-only pacing in CRT-D: insights into arrhythmic burden
D D Anutoni, A A Faur-Grigori, A M Bondoc, A M Bumbar, L Cirin, S A Luca, S Crisan, C T Luca, D Gaita, D Cozma, C VacarescuAbstract
Background
Left ventricular (LV)–only pacing has been shown to be non-inferior to biventricular (BiV) pacing in selected patients undergoing cardiac resynchronization therapy (CRT). Whether LV-only pacing influences ventricular arrhythmic burden in patients implanted with CRT-D devices remains insufficiently explored.
Purpose
To compare the incidence of ventricular arrhythmias requiring device therapy and CRT response in patients with CRT-D devices programmed for LV-only pacing versus conventional BiV pacing.
Methods
Consecutive patients implanted with a CRT-D device for primary prevention were included and programmed either to optimized LV-only pacing or standard BiV pacing, according to clinical and electrical criteria. Prospective follow-up was performed at 6-month intervals, including echocardiographic assessment and device interrogation. Ventricular arrhythmic events treated with antitachycardia pacing or shock were recorded. CRT response was defined by improvement in left ventricular ejection fraction (LVEF) and reverse remodeling; super-responders were defined as patients achieving LVEF ≥45% and ≥30% reduction in left ventricular end-systolic volume.
Results
A total of 81 patients (67 males, mean age 63.1 ± 10.6 years) with dilated cardiomyopathy, left bundle branch block, and NYHA class II–III heart failure were included. Thirty-three patients received optimized LV-only pacing and 48 standard BiV pacing. Non-ischemic cardiomyopathy was more prevalent in the LV-only group (69.6% vs 45.8%). During a mean follow-up of 49.3 ± 47.6 months, LV-only pacing was associated with a lower incidence of ventricular arrhythmic events compared with BiV pacing (9.0% vs 37.5%, p = 0.004). LV-only pacing was also associated with a higher rate of CRT response and a greater proportion of super-responders.
Conclusions
In this observational cohort, LV-only pacing in CRT-D recipients was associated with a lower incidence of device-treated ventricular arrhythmias and a higher rate of favorable reverse remodeling compared with BiV pacing. These findings are hypothesis-generating and suggest that, in carefully selected patients achieving effective LV-only fusion pacing, arrhythmic risk may be lower. Larger prospective studies are required to determine the clinical implications for long-term arrhythmic risk stratification.