Substrate-guided ablation of haemodynamically tolerated and untolerated ventricular tachycardia in patients with structural heart disease: effect of cardiomyopathy type and acute success on long-term outcome.

Aims: The purpose of this study was to evaluate the outcomes of purely substrate-guided ventricular tachycardia (VT) ablation in patients with non-ischaemic dilated cardiomyopathy (NIDCM) and ischaemic cardiomyopathy (ICM) and the impact of acute procedural success on long-term outcome.

Methods And Results: One hundred and forty-two patients (65 ± 12 years old, 72% male) with ICM (n = 87) and with NIDCM (n = 55) underwent substrate-guided VT ablation. The ablation approach involved eliminating all LP regions and ablating all scar border zone regions with 10 or more out of 12 pace-matching. All patients were followed with regular implantable defibrillator interrogations for mean 641 ± 301 days. Complete acute success (no inducible VT) was achieved in 60 patients with ICM (69%) and in 29 patients with NIDCM (53%) (P = 0.03). Partial success (elimination of clinical VT only) was obtained in nine patients with ICM (10%) and in four patients with NIDCM (7%) (P = 0.14). Procedural failure (clinical VT still inducible) occurred in 18 patients within the ICM group (21%) and in 22 patients of the NIDCM (40%) (P = 0.04). Overall, 51 patients presented with recurrence of ventricular arrhythmias: 23 in the group with ICM (26%) and 28 in the group with NIDCM (51%) (P = 0.03). Long-term success was related to acute procedural outcome.

Conclusions: Substrate-guided ablation is an effective approach in the treatment of VT with long-term outcome directly related to acute procedural success. Success rates are significantly lower in patients with NIDCM compared with those with ICM.