Clinical and electrophysiological differences between patients with arrhythmogenic right ventricular dysplasia and right ventricular outflow tract tachycardia.

AIMS Radiofrequency catheter ablation is considered first line treatment for symptomatic patients with right ventricular outflow tract tachycardia (RVOT). The role of ablation in arrhythmogenic right ventricular dysplasia (ARVD) is more limited. As such, differentiating between the two conditions is essential. METHODS AND RESULTS This study compared non-invasive findings, magnetic resonance images (MRI), invasive electrophysiological characteristics, results of ablation and long-term outcome in 50 consecutive patients with RVOT (33) or ARVD (17). Structural abnormalities were uniform in the ARVD group; in addition 18 (54%) of the RVOT tachycardia group had MRI abnormalities. At electrophysiological study the tachycardia in the ARVD group displayed features of re-entry in over 80%, but behaved with a triggered automatic basis in 97% with RVOT. Ablation was complete or partial success in 12 (71%) patients with ARVD and ventricular tachycardia (VT) recurred in eight (48%). In the RVOT patients, ablation was a complete success in 97% with recurrent VT in 6%. Long-term success in the RVOT patients was 95% in both patients with and without MRI abnormalities. CONCLUSIONS Electrophysiological characterization can differentiate ARVD from RVOT. The finding of abnormalities on MRI does not have any bearing on arrhythmia mechanism, acute or long-term success of RFA.