Repetitive monomorphic ventricular tachycardia originating from the inferior tricuspid annulus

Abstract

We report a case of an otherwise healthy 63-year-old male with incessant, highly symptomatic ventricular arrhythmia that displayed over 60,000 premature ventricular contractions and 499 runs of non-sustained ventricular tachycardia (VT) during 24 hours of ECG monitoring. The ventricular ectopy had a QRS morphology of the left bundle branch block (LBBB), however, with a superior axis. Structural heart disease was absent and the history was negative. Therefore the arrhythmia was considered to be atypical idiopathic repetitive monomorphic VT. Radiofrequency catheter ablation in an inferior region of the tricuspid ring at a site with good pacemap was successful. We conclude that idiopathic repetitive monomorphic VT may originate from uncommon locations and that QRS morphology (superior axis, LBBB, notching in inferior leads, transition at V4, duration ≥ 160 ms) can help diagnose inferior free wall tricuspid location. (Cardiol J 2008; 15: 277-280)