Catheter Ablation of Right Ventricular Endocavitary Arrhythmias.

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.