Long-Term Follow-Up of Inducible Bundle Branch Reentrant Ventricular Tachycardia in Patients Without Structural Heart Disease: Beyond the Electrophysiology Laboratory.

BACKGROUND

Bundle branch reentrant ventricular tachycardia (BBR-VT) is a rare form of VT occurring in patients with structural heart disease (SHD). Rarely, it can also occur in the absence of SHD. Understanding its clinical and electrophysiologic (EP) properties and outcomes post-catheter ablation (CA) is crucial.

OBJECTIVE

We present a series of patients with bundle branch reentrant ventricular tachycardia (BBR-VT) and structurally normal hearts, comparing their clinical and electrophysiological characteristics, as well as long-term outcomes, with those of patients with the classic form of BBR-VT, in whom the arrhythmia was induced in the presence of ventricular dysfunction.

METHODS

All cases of BBR-VT diagnosed during electrophysiological (EP) studies in our lab were evaluated. Clinical characteristics and EP findings were described.

RESULTS

Sixteen patients (12/16 male; mean age 50 ± 21 years) with BBR-VT were studied from 2009 to 2020, with a mean follow-up of 70 ± 16 months. Notably, nearly half (7/16; 43%) had no structural heart disease (SHD). Among these, three had myotonic dystrophy, two had SCN5A mutations, one had ajmaline-induced BBR-VT, and one had idiopathic BBR-VT. BBR-VT was induced with a mean cycle length of 322 ± 22 ms and was well tolerated in 10/16 patients. Right bundle branch catheter ablation was performed using an 8 mm solid-tip catheter, leading to an HV interval increase from 72 ± 9 ms to 100 ± 23 ms. One patient developed total AV block. Postprocedure, device implantation was required in 13/16 patients (dual-chamber pacemaker: 10; ICD: 3). Notably, no patient experienced VT recurrence during follow-up.

CONCLUSION

BBR-VT is traditionally associated with dilated cardiomyopathy, but it can also occur in structurally normal hearts. Myotonic dystrophy and SCN5A mutations may underlie some cases. Right bundle branch ablation is an effective treatment, though device implantation is usually required.