Abstract 1740: Risk of Proarrhythmia Following Alcohol Septal Ablation in Patients with Hypertrophic Obstructive Cardiomyopathy
Background: Alcohol septal ablation (ASA) is a promising treatment option for patients with hypertrophic obstructive cardiomyopathy (HOCM), but the creation of myocardial infarct during the procedure has raised concern about the proarrhythmic risk of ASA. We analyzed the incidence of clinically significant ventricular tachycardia (VT) and sudden cardiac death (SCD) following ASA at our center.
Methods: A total of 97 ASAs in 88 patients were performed between 1998 and 2007 at MGH. 34 of these patients had an implantable cardiac defibrillator (ICD) or pacemaker (PPM) implanted prior to or immediately following ASA. 8 of 34 patients had prior ICD implants for either secondary (n=4) or primary (n=4) prevention for SCD. 8 patients had prior PPMs. 3 patients had implantation of ICD post-ASA and 15 patients had PPM implanted following ASA due to atrioventricular block (AVB). Clinical records as well as device data were analyzed to determine incidence of VT or SCD following ASA.
Results: There were no deaths attributable to SCD in our cohort of 88 patients (mean follow-up 35 +/− 21 months, range 4 to 70 months). 1 patient with a previous ICD for primary prevention had VT storm 6 days following ASA. 1 patient who had a cardiac arrest 11 days following the ASA (thought to be a bradycardic arrest, since he had intermittent high grade AVB post-ASA) received an ICD. Neither of these patients had subsequent detections or therapies for VT. 1 patient was upgraded to an ICD following ASA due to NSVT, and 2 patients had ICD implants for NSVT or high risk of SCD. The former had subsequent detection of NSVT 24 months after implant, and therapy for VT 3 years later. 2 patients had upgrades of their PPM to an ICD > 12 months after ASA (for positive electrophysiology studies at other centers), but had no detection or therapies during the follow-up period. No other patients had therapies for tachyrrhythmias.
Conclusion: In our experience of 97 procedures, we observed 1 episode of VT storm in the first week following ASA, 1 cardiac arrest, likely bradycardic, in the first 2 weeks after ASA, and only 1 patient with clinically significant VT years after ASA. Our data suggest that close follow-up is warranted in the 2 weeks after ASA, but that ASA does not seem to have a long-term proarrhythmic effect in patients with HOCM.