Long-term results of catheter ablation for ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy/dysplasia

Abstract Aims This study analyzed the arrhythmogenic substrates and mechanisms of ventricular tachycardia (VT), and long-term outcomes of catheter ablation in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). Methods Nine patients (1 female, 40±17 years) with ARVC/D and sustained monomorphic VT (SMVT) exhibiting left bundle branch block morphology of the QRS complex were studied. The diagnosis of ARVC/D was confirmed by means of echocardiography, magnetic resonance imaging, and electroanatomic mapping in all patients. Results The patients underwent 10 ablation procedures. At the initial ablation, the mean VT rate was 196±21 (170–240) bpm. In total, 17 VT types were observed. One VT type with left axis (+I, aVL), or right axis (+II,III,aVF) of the QRS complex was present in 3 and 1 patient, respectively. Two VT types of left and intermediate (+I, II, aVL) axis or of left and right axis of the QRS complex were observed in 3 and 2 patients, respectively. Multiple VT types with left axis QRS complex recurred in 1 patient. One VT displayed characteristics of focal arrhythmia, the mechanism of remaining VTs was clearly macroreentrant. The critical slow-conducting isthmus of the reentry circuit was located at the infero-lateral aspect of tricuspid annulus and was bounded by the annulus and baso-lateral wall scar in 7 VTs; the isthmus was located within the scars in the remaining VTs. During 52±31 (12–93) month follow-up since the last ablation, 8 (89%) patients remained free from any VT recurrence without antiarhythmic drug. Conclusions Patients with ARVC/D frequently presented ≥1 SMVT type. The critical isthmus of reentry circuit was dominantly located close to the tricuspid annulus. Long-term outcome of extensive endocardial ablation was favorable with isolated VT recurrences in one patient.