Subcutaneous Defibrillator Implantation With or Without Defibrillation Test: The Primary Results of the Randomized PRAETORIAN-DFT Trial.

backgroundTo improve survival of patients at risk of sudden cardiac death, subcutaneous implantable cardioverter defibrillators (S-ICDs) require optimal implant positioning for effective shocks. Defibrillation (DF) testing is recommended but carries serious risks. The PRAETORIAN score predicts defibrillation outcomes on the basis of chest X-ray. The PRAETORIAN-DFT (Prospective Randomized Comparative Trial of Subcutaneous Implantable Cardioverter Defibrillator Implantation With and Without Defibrillation Testing) trial evaluated whether omission of DF testing guided by the PRAETORIAN score is noninferior for first-shock efficacy.

methodsIn this multinational trial, S-ICD patients from 37 centers were randomized to DF testing or no DF testing. In the No-DF testing group, the PRAETORIAN score was evaluated before discharge. The primary end point was failed first shock for spontaneous ventricular arrhythmias, as a surrogate for defibrillation success, tested for noninferiority with a 3% absolute risk margin. Secondary end points included mortality, potential DF testing-related complications, and S-ICD revisions.

resultsThe included 965 patients (No-DF testing, n=483; DF testing, n=482) were followed for a median of 41 months. Failed first shock for spontaneous ventricular arrhythmia occurred in 1.7% of the No-DF testing group versus 2.3% of the DF testing group (-0.6% [95% CI, -2.6 to 1.4],

conclusionsPRAETORIAN score-guided omission of DF testing after S-ICD implantation did not increase the risk of failed first shocks for spontaneous ventricular arrhythmias and reduced procedural risk without increasing S-ICD revisions. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03495297.