Progressive outcomes of bundle branch reentrant ventricular tachycardia in patients without structural heart disease

Abstract

Ablation strategies to treat bundle branch reentrant ventricular tachycardia (BBRT) are well described. However, reports of long-term follow-up outcomes in BBRT patients without structural heart disease (SHD) are limited. The purpose of this study was to investigate the long-term follow-up prognosis of BBRT patients without SHD. Changes in electrocardiographic and echocardiographic parameters were used to evaluate progression during follow-up. Potential pathogenic candidate variants were screened using a specific gene panel. Eleven consecutive BBRT patients without obvious SHD based on echocardiographic and cardiovascular magnetic resonance imaging results were enrolled. Median age was 20 (11-48) years, and median follow-up time was 72 months. During follow-up, PR interval [206 (158-360) ms vs 188 (158-300) ms; P = .018] and QRS duration [187 (155-240) ms vs 164 (130-178) ms; P = .008] each increased significantly compared with postablation. Right- and left-sided chamber dilation and reduced left ventricular ejection fraction (LVEF) also were observed. Clinical deterioration or events occurred in 8 patients: 1 sudden death; 3 both complete heart block and reduced LVEF; 2 significantly reduced LVEF; and 2 prolonged PR interval. Genetic testing results showed that 6 of 10 patients (excluding the patient with sudden death) had ≥1 potential pathogenic candidate variants. Further deterioration of His-Purkinje system conduction was observed in young BBRT patients without SHD after ablation. The His-Purkinje system may be the first target of genetic predisposition.