Bundle Branch Reentrant Tachycardia Concomitant With Atrial Tachycardia in Patients Without Structural Heart Disease.

BACKGROUND: Bundle branch reentry ventricular tachycardia (BBRT) in patients without structural heart disease (SHD) has been well-documented. However, the occurrence of concomitant atrial tachycardia (AT) in this cohort remain poorly characterized. The study aimed to investigate the prevalence, clinical characteristics, and electrophysiological properties of concomitant AT in patients with BBRT. METHODS: Eighteen patients without SHD were enrolled. Detailed electrophysiological studies were performed to identify and characterize concomitant ATs. Catheter ablation was performed for both BBRT and atrial ATs. RESULTS: Among 18 patients with BBRT, 6 patients (33.3%; mean age 26.3 years) presented with a total of 7 ATs. Three patients had a history of AT ablation, two exhibited BBRT concomitant with AT during the index procedure, and two developed AT following BBRT ablation. All ATs originated from the right atrium, with the following distribution: coronary sinus ostium (CSO) (n = 4), typical atrial flutter (AFL) (n = 2) and mid-crista terminalis (MCT) (n = 1). The mean tachycardia cycle length (TCL) was 337±61 ms. Acute procedural success was achieved in all cases. During a mean follow-up of 54.1±26.0 months, all patients remained free from AT and BBRT recurrence. However, progressive deterioration of left ventricular function requiring cardiac resynchronization therapy occurred in one patient, and two patients developed ventricular enlargement. CONCLUSIONS: Concomitant AT was observed in one-third of patients with BBRT without SHD. Catheter ablation proved effective in treating both arrhythmias. Intensive long-term monitoring of cardiac function is recommended in this population.