1-Year Prospective Evaluation of Clinical Outcomes and Shocks: The Subcutaneous ICD Post Approval Study

Abstract

Objectives: This study evaluated spontaneous arrhythmias and clinical outcomes in the S-ICD System PAS (Subcutaneous Implantable Cardioverter-Defibrillator Post Approval Study) cohort.

Background: The U.S. S-ICD PAS trial patient population more closely resembles transvenous ICD cohorts than earlier studies, which included many patients with little structural heart disease and few comorbidities. Early outcomes and low peri-operative complication rates were demonstrated in the S-ICD PAS cohort, but there are no data detailing spontaneous arrhythmias and clinical outcomes.

Methods: The S-ICD PAS prospective registry included 1,637 de novo patients from 86 U.S. centers. Descriptive statistics, Kaplan-Meier time to event, and multivariate logistic regression were performed using data out to 365 days.

Results: Patients (68.5% men; mean ejection fraction of 32.0%; 42.9% ischemic; 13.4% on dialysis) underwent implantation for primary (76.6%) or secondary prevention indication. The complication-free rate was 92.5%. The appropriate shock (AS) rate was 5.3%. A total of 395 ventricular tachycardia (VT) or fibrillation (VF) episodes were appropriately sensed, with 131 (33.2%) self-terminating. First and final shock efficacy (up to 5 shocks) for the 127 discrete AS episodes were 91.3% and 100.0%, respectively. Discrete AS episodes included 67 monomorphic VT (MVT) and 60 polymorphic VT (PVT)/VF, with first shock efficacy of 95.2% and 86.7%, respectively. There were 19 storm events in 18 subjects, with 84.2% conversion success. Storm episodes were more likely PVT/VF (98 of 137).

Conclusions: In the first year after implantation, a predominantly primary prevention population with low ejection fraction demonstrated a high complication-free rate and spontaneous event shock efficacy for MVT and PVT/VF arrhythmias at rapid ventricular rates. (Subcutaneous Implantable Cardioverter-Defibrillator System Post Approval Study [S-ICD PAS; NCT01736618).

Keywords: arrhythmia; heart failure; implantable cardioverter-defibrillator; subcutaneous ICD; sudden cardiac death; ventricular arrhythmia.

Conflict of interest statement

Author Relationship With Industry This study was supported by Boston Scientific. Dr. Burke has been a consultant and has received honoraria from Boston Scientific and AtaCor Medical; has received research grants from Boston Scientific, Medtronic, and St. Jude Medical; and holds equity in AtaCor Medical. Dr Aasbo has been a consultant and has received honoraria from Boston Scientific and Biotronik. Dr. El-Chami has received honoraria for consulting for Medtronic and Boston Scientific. Dr. Dinerman has received consulting fees from Boston Scientific, Medtronic, and Abbott. Dr. Hanon has received compensation for services from Boston Scientific. Dr. Weiss has received honoraria for speaking and serving as a consultant from Boston Scientific, Medtronic, Biotronic, and Biosense Webster. Dr. Gold has received honoraria and consulting fees from Boston Scientific and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.