TỶ LỆ VÀ YẾU TỐ LIÊN QUAN ĐẾN TRIỆT ĐỐT THÀNH CÔNG NGOẠI TÂM THU THẤT TỪ ĐƯỜNG RA THẤT PHẢI TẠI BỆNH VIỆN TIM TÂM ĐỨC

Abstract

Background: Premature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) are a common form of ventricular arrhythmia that can cause symptoms and lead to tachycardia-induced cardiomyopathy. Catheter-based radiofrequency ablation is an effective treatment modality. Importantly, the combined analysis of bipolar and unipolar electrograms helps optimize the localization of the arrhythmic focus, thereby improving the success rate. In Vietnam, data on the procedural success rates of this therapy remain limited. Objective: To determine the success rate of PVC ablation from the RVOT and identify associated factors. Methods: A cross-sectional study was conducted at Tam Duc Heart Hospital from July 2024 to August 2025, enrolling patients who underwent ablation for RVOT PVCs. Results: A total of 76 patients were included, with a mean age of 45,36 ± 15.89 years; 77.6% were female. Previous ablation had been performed in 5.3% of patients, and 46,1% had dyslipidemia. The most frequent symptom was palpitations (84,2%), with a median symptom duration of 12 months. Echocardiographic and laboratory indices were mostly within normal ranges. On surface ECG, all patients exhibited monomorphic PVCs; the mean PVC burden on 24-hour Holter monitoring was 25,05 ± 12,97%. The mean procedure time was 1,80 ± 0,54 hours. Electrophysiological findings included a median EAT of 36 ms on bipolar electrograms and a median IMSDL of 14 ms on unipolar electrograms; a typical QS pattern was present in 98,7%. The overall acute success rate was 92,1%, highest at the mid-septal site (28,9%). Success rates differed significantly by ablation site (p = 0,044). Both EAT ms and IMSDL were strongly associated with higher success (p = 0,002 and 0,023). Conclusion: The study demonstrated that radiofrequency ablation of RVOT PVCs at Tam Duc Heart Hospital achieved a high success rate (92.1%). EAT and IMSDL were significantly associated with successful ablation. These findings suggest future research directions on integrating bipolar and unipolar electrogram analysis to optimize focus localization, while also providing additional real-world evidence from Vietnam.