B-PO05-033 PACEMAKER IMPLANTATION AFTER SELECTIVE ALCOHOL SEPTAL ABLATION

Abstract

Complete heart block (CHB) with permanent pacemaker (PPM) placement is a known risk of alcohol septal ablation (ASA) for hypertrophic cardiomyopathy. Historically, the incidence has been around 10% in all-comer populations. However, rates of 25% are reported in centers that selectively target older, higher risk patients (pts). Understanding predictors of CHB in this evolving cohort is important. Report baseline characteristics, associated factors (AF) of PPM placement, longer-term pacing need following ASA in a high-volume HCM center. 94 consecutive pts underwent ASA from 2/2017 to 12/2020. 25 were excluded due to prior septal reduction or device. Criteria for PPM included persistent post-ASA CHB >24 hours, recurrent pacing due to 2nd degree HB/ transient CHB >24 hours. 69 pts (mean age 65.7 ± 11 years, females 53.6%) were included. 19 (27.5%) required PPM prior to discharge, 6 (31.5%) of whom were prohibitive surgical risk for myectomy (20.3% PPM rate in pts not at prohibitive surgical risk). All had reduction in peak provoked gradient (pre-procedure mean 149.8 mm Hg vs. post-procedure mean 10.5 mmHg, p<0.01) and improved NYHA class. Comparison of baseline clinical, ECG, and procedural characteristics (e.g., peak troponin and gradient reduction) yielded no AF of PPM implantation, with exception of intraprocedural CHB (OR 12.4, 95% CI 3.4 - 45.3, p<0.0001). Post procedure PR prolongation >50 ms (OR 6.1, 95% CI 1.5 - 24.5, p = 0.01), first-degree AV block with RBBB and LAFB (OR 6.1, 95% CI 1.5 - 24.5, p = 0.01) and change in QRS axis >700 (OR 5.3, 95% CI 1.4 - 18.9, p= 0.01) was also associated with PPM. At 1 month, 16 pts (84.2%) required >1% RV pacing (mean 59.2%) suggesting appropriateness of PPM implantation. At 3 months 10 pts (52.6%) required pacing (mean 52.4%) indicating some late recovery. No procedural factors were associated with PPM following ASA with exception of intraprocedural CHB. Daily ECGs identified dynamic abnormalities associated with PPM. Short term follow up suggests PPM criteria are appropriate, with longer term follow up showing some recovery. As higher risk cohorts are targeted for ASA, PPM risk factors of long term pacing will be vital.