Outcome of ventricular tachycardia ablation in patients with nonischemic cardiomyopathy: the impact of noninducibility.

BACKGROUND: Ablation failure and recurrence rates after ventricular tachycardia (VT) ablation in nonischemic cardiomyopathy are high and the optimal procedural end point is not well defined. This study assessed the outcome after ablation, the impact of noninducibility, and other potential predictors of VT recurrence. METHODS AND
RESULTS: Forty-five patients with nonischemic cardiomyopathy (60±16 years; left ventricular ejection fraction, 44±14%) accepted for VT ablation were included. Epicardial mapping was performed in 29 (64%). A median of 2 (first-to-third quartile, 2-4) VTs (cycle length, 342±77 ms) were induced per patient. After ablation, the complete programmed electric stimulation protocol (3 drive cycle length, 3 extrastimuli ≥200 ms, and burst≥2 sites) was repeated. Complete success (noninducibility of any monomorphic VT) was achieved in 17 patients (38%), partial success (elimination of clinical VT, persistent inducibility of nonclinical VT) in 17 patients (38%), and failure (persistent inducibility of clinical VT) in 11 patients (24%). During 25±15 months of follow-up, VT occurred in 24 patients (53%), but the 6-month VT burden was reduced by ≥75% in 79%. Recurrence rates were low after complete procedural success (18%), but high after both partial success (77%) and failure (73%). Non-complete procedural success was the strongest predictor of VT recurrence (hazard ratio, 8.20; 95% confidence interval, 2.37-28.43; P=0.001).
CONCLUSIONS: Although 53% of patients had VT during follow-up, the 6-month VT burden was decreased by ≥75% in 79%. Recurrence rates are low after complete procedural success, but high after both partial success and failure. Non-complete procedural success was the strongest predictor of VT recurrence.