BACKGROUND

Right ventricular (RV) endocavitary arrhythmias remain poorly characterized.

OBJECTIVES

The purpose of this study was to define the clinical presentation, ablation outcomes, and long-term prognosis of RV endocavitary arrhythmias.

METHODS

Among 3,873 patients undergoing ventricular arrhythmia ablation between 2013 and 2025, 53 (1.4%) were included (mean age 45.4 ± 16.9 years, 64% male, mean left ventricular ejection fraction 54 ± 11%).

RESULTS

Forty-three (81%) had structurally normal hearts and 10 (19%) had nonischemic cardiomyopathy, including 7 with premature ventricular contraction (PVC)-mediated cardiomyopathy and 3 with idiopathic nonischemic cardiomyopathy. Ablation indications included PVCs (n = 25), PVC-triggered ventricular fibrillation (VF) (n = 20), and ventricular tachycardia (n = 8). PVC QRS duration independently predicted developing PVC-mediated cardiomyopathy (P = 0.02). PVCs-triggering VF had shorter coupling intervals (CIs) (320 [295-358] vs 440 [400-470] ms; P < 0.05) and more frequently originated at the lateral moderator band (MB) (P = 0.03), where they also had shorter CIs than medial MB PVCs (P = 0.01). Ablation targets included the MB (n = 47), anterior papillary muscle (PM) (n = 3), inferior PM (n = 2), and conus PM (n = 1). Postablation increase in sinus rhythm QRS duration (98 [84-102] to 102 [90-114] ms; P < 0.01), V1 intrinsicoid deflection (22 [18-27] to 26 [20-95] ms; P < 0.01), and new right bundle branch block (15% of patients) did not translate into RV dysfunction or worsening tricuspid valve function. Radiofrequency energy was used in 49 patients, adjunctive cryoablation in 6, and cryoablation alone in 4. At 3.6 (1.6-5.7) years follow-up, 89% achieved clinical success with reduced antiarrhythmic drug use.

CONCLUSIONS

RV endocavitary arrhythmias typically occur in structurally normal hearts as focal PVCs. PVCs-triggering VF have shorter CIs and preferentially arise from the lateral MB. Ablation is effective in management.