Subcutaneous implantable cardioverter-defibrillator and defibrillation testing: A propensity-matched pilot study

Heart Rhythm. 2021 Dec;18(12):2072-2079. doi: 10.1016/j.hrthm.2021.06.1201. Epub 2021 Jun 30.

Abstract

Background: To date, only a few comparisons between subcutaneous implantable cardioverter-defibrillator (S-ICD) patients undergoing and those not undergoing defibrillation testing (DT) at implantation (DT+ vs DT-) have been reported.

Objective: The purpose of this study was to compare long-term clinical outcomes of 2 propensity-matched cohorts of DT+ and DT- patients.

Methods: Among consecutive S-ICD patients implanted across 17 centers from January 2015 to October 2020, DT- patients were 1:1 propensity-matched for baseline characteristics with DT+ patients. The primary outcome was a composite of ineffective shocks and cardiovascular mortality. Appropriate and inappropriate shock rates were deemed secondary outcomes.

Results: Among 1290 patients, a total of 566 propensity-matched patients (283 DT+; 283 DT-) served as study population. Over median follow-up of 25.3 months, no significant differences in primary outcome event rates were found (10 DT+ vs 14 DT-; P = .404) as well as for ineffective shocks (5 DT- vs 3 DT+; P = .725). At multivariable Cox regression analysis, DT performance was associated with a reduction of neither the primary combined outcome nor ineffective shocks at follow-up. A high PRAETORIAN score was positively associated with both the primary outcome (hazard ratio 3.976; confidence interval 1.339-11.802; P = .013) and ineffective shocks alone at follow-up (hazard ratio 19.030; confidence interval 4.752-76.203; P = .003).

Conclusion: In 2 cohorts of strictly propensity-matched patients, DT performance was not associated with significant differences in cardiovascular mortality and ineffective shocks. The PRAETORIAN score is capable of correctly identifying a large percentage of patients at risk for ineffective shock conversion in both cohorts.

Trial registration: ClinicalTrials.gov NCT04373876.

Keywords: Defibrillation testing; PRAETORIAN score; Propensity matching; Subcutaneous implantable cardioverter-defibrillator; Sudden cardiac death.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Observational Study

MeSH terms

  • Comparative Effectiveness Research
  • Death, Sudden, Cardiac / epidemiology
  • Death, Sudden, Cardiac / prevention & control
  • Defibrillators, Implantable* / adverse effects
  • Defibrillators, Implantable* / statistics & numerical data
  • Electric Countershock / statistics & numerical data*
  • Equipment Failure / statistics & numerical data*
  • Equipment Failure Analysis* / methods
  • Equipment Failure Analysis* / statistics & numerical data
  • Europe / epidemiology
  • Female
  • Humans
  • Male
  • Materials Testing / methods
  • Materials Testing / statistics & numerical data
  • Middle Aged
  • Propensity Score
  • Risk Assessment / methods
  • Tachycardia, Ventricular* / mortality
  • Tachycardia, Ventricular* / therapy

Associated data

  • ClinicalTrials.gov/NCT04373876