Right ventricular outflow tract aneurysm in arrhythmogenic right ventricular cardiomyopathy: The mechanism of ventricular tachycardia.

BACKGROUND

Regional aneurysms of the right ventricular (RV) free wall, identified through imaging, are a major criterion for arrhythmogenic RV cardiomyopathy (ARVC). The electrophysiological characteristics of patients with RV outflow tract (RVOT) aneurysms remain unclear.

OBJECTIVE

This study aimed to determine the characteristics of ventricular tachycardia (VT) in patients with ARVC with RVOT aneurysms.

METHODS

We analyzed 106 patients with VT who met the diagnostic criteria for ARVC and underwent ablation. RVOT aneurysms were identified using magnetic resonance imaging or echocardiography. VT origins were determined based on standard mapping criteria and confirmed by elimination through ablation.

RESULTS

RVOT aneurysms were identified in 10 patients (9.4%) with a total of 18 VTs. All patients had VTs with a left bundle branch block (LBBB) inferior axis morphology, whereas 5 (50%) also had LBBB intermediate axis VTs and another 3 (30%) had LBBB superior axis VTs. An epicardial-endocardial approach was used in all cases, with an average of 2.2 ± 1.4 procedures per patient. The RVOT aneurysm served as a substrate for VT and formed an anatomic barrier with the tricuspid valve for VT and was associated with 15 VTs (83.3%). Catheter ablation homogenized the aneurysm and involved linear ablation from the aneurysm to the tricuspid valves and pulmonary valves, rendering all VTs noninducible.

CONCLUSION

In patients with ARVC with RVOT aneurysms undergoing VT ablation, the aneurysm and the isthmus between the aneurysm and perivalvular fibrosis may contribute to VT circuits. Electrical homogenization of the aneurysm combined the linear ablation to the anatomic scar could be an alternative approach and may reduce VT recurrence.