The risk of non-sustained ventricular tachycardia after percutaneous alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

Percutaneous alcohol septal ablation (ASA) becomes an alternative option of treatment for symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). The procedure relieves left ventricular outflow tract obstruction, but produces a myocardial scar in patients who already have a substrate for life-threatening ventricular arrhythmia. To examine the effect of ASA on the occurrence of non-sustained ventricular tachycardia (nsVT) on 24 h ambulatory Holter monitoring in HOCM patients. Sixty-one consecutive patients (34 males, mean age 48 years), who underwent ASA between 1997 and 2003 were analyzed. Holter recordings were performed in each patient before and after ablation. Follow-up ranged from 60 to 125 months (median 116 months). The mean number of Holter recordings per patient was 2.7 (range 1-11) before and 8.3 (range 2-23) after ASA (p < 0.001). Non-sustained ventricular tachycardia occurred in 14 patients before and 27 patients after ASA (23 vs. 44%, p = 0.01). The percentage of Holter recordings with nsVT before and after ablation was similar (14.5 vs. 15.7%, p = 0.56, respectively). No difference was observed between the number of nsVT per Holter recording before and after ablation (0.21 vs. 0.24%, p = 0.65, respectively). The percentage of patients with nsVT after ASA was comparable to the proportion of patients with nsVT in a control group consisting of 705 patients with hypertrophic cardiomyopathy under follow-up at our institution (44.3 vs. 43.2%, p = 0.91). There was no significant difference in percentage of Holter recordings with nsVT with respect to sex, amount of alcohol used during ASA, peak creatine phosphokinase level, and gradient reduction at rest. Alcohol septal ablation affected neither the percentage of Holter recordings with nsVT nor the number of nsVT episodes per Holter recording among HOCM patients.