Subcutaneous implantable cardioverter-defibrillator Post-Approval Study: Clinical characteristics and perioperative results

Abstract

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to reduce short- and long-term complications associated with transvenous ICD leads. Early multicenter studies included younger patients with less left ventricular systolic dysfunction and fewer comorbidities than cohorts with traditional ICD.

Objective: The purpose of this study was to characterize patient selection and the acute performance of the S-ICD in a contemporary real-world setting.

Methods: The S-ICD Post-Approval Study is a prospective registry involving 86 US centers. Patients were enrolled if they met criteria for S-ICD implantation, passed an electrocardiogram screening test, and had a life expectancy of >1 year. Analyses of descriptive statistics, Kaplan-Meier time to event, and multivariate logistic regression were performed.

Results: The study includes 1637 patients who underwent S-ICD implantation. The cohort included 68.6% (1123/1637) male patients, and 13.4% (220/1636) were receiving dialysis for end-stage renal disease. The mean age was 52 ± 15 years, with a mean left ventricular ejection fraction of 32.0% ± 14.6%. Electrocardiogram screening was successful for at least 1, 2, or 3 vectors in 100%, 93.8%, and 51.4% of patients, respectively. Medical imaging (65.1%, 1065/1636) and general anesthesia (64.1%, 1048/16) were used in a majority of patients, and 52.2% (855/1637) were implanted with the 2-incision technique. Induced ventricular tachycardia/ventricular tachycardia was successfully converted in 98.7% (1394/1412) of patients. The 30-day complication-free rate was 96.2%. Predictors of complications included diabetes, younger age, and higher body mass index.

Conclusion: Contemporary US patients with S-ICD have more comorbidities than do previous cohorts with S-ICD, but they are younger with more end-stage renal disease than do patients with transvenous ICD. Implantation success is high, and short-term complication rates are acceptable.

Trial registration: ClinicalTrials.gov NCT01736618.

Keywords: Arrhythmia; Heart failure; Implantable cardioverter-defibrillator; Registry; Subcutaneous ICD; Sudden cardiac death; Ventricular arrhythmia.