Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: Analysis of All Appropriate Therapy in the PRAETORIAN Trial

Research output: Contribution to journalResearch articleContributedpeer-review


  • PRAETORIAN Investigators‡ - (Author)
  • Department of internal Medicine with focus on Cardiology (at Herzzentrum Dresden)
  • Kerckhoff Heart Center
  • Helios Klinikum Pirna
  • St. Antonius Hospital
  • University Medicine Mannheim
  • Emory University
  • Klinik für Innere Medizin III: Hämatologie
  • St. George's University of London
  • Hospital of the Ludwig-Maximilians-University (LMU) Munich
  • The Valley Health System
  • Heart Center Leipzig
  • Radboud University Medical Center
  • University College London and Barts Heart Centre
  • Homolka Hospital
  • Maastricht University Medical Centre (UMC+)
  • Amphia Hospital
  • Oxford University Hospitals NHS Foundation Trust
  • Catharina Hospital Eindhoven
  • CorVita Science Foundation
  • Liverpool Heart and Chest Hospital NHS Foundation Trust
  • Imperial College London
  • University Hospital of Würzburg
  • Structure and Materials Mechanics Research Institute at the Dresden University of Technology (SWM)
  • IT University of Copenhagen
  • Medical Spectrum Twente
  • Northwestern Health Sciences University
  • Medisch Centrum Leeuwarden
  • Yale University
  • Columbia University Irving Medical Center (CUMC)
  • Icahn School of Medicine at Mount Sinai
  • Englewood Hospital and Medical Center
  • Jena University Hospital
  • University of Chicago Pritzker School of Medicine
  • The Ohio State University Comprehensive Cancer Center - The James
  • European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart


BACKGROUND: The PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) showed noninferiority of subcutaneous implantable cardioverter defibrillator (S-ICD) compared with transvenous implantable cardioverter defibrillator (TV-ICD) with regard to inappropriate shocks and complications. In contrast to TV-ICD, S-ICD cannot provide antitachycardia pacing for monomorphic ventricular tachycardia. This prespecified secondary analysis evaluates appropriate therapy and whether antitachycardia pacing reduces the number of appropriate shocks.

METHODS: The PRAETORIAN trial was an international, investigator-initiated randomized trial that included patients with an indication for implantable cardioverter defibrillator (ICD) therapy. Patients with previous ventricular tachycardia <170 bpm or refractory recurrent monomorphic ventricular tachycardia were excluded. In 39 centers, 849 patients were randomized to receive an S-ICD (n=426) or TV-ICD (n=423) and were followed for a median of 49.1 months. ICD programming was mandated by protocol. Appropriate ICD therapy was defined as therapy for ventricular arrhythmias. Arrhythmias were classified as discrete episodes and storm episodes (≥3 episodes within 24 hours). Analyses were performed in the modified intention-to-treat population.

RESULTS: In the S-ICD group, 86 of 426 patients received appropriate therapy, versus 78 of 423 patients in the TV-ICD group, during a median follow-up of 52 months (48-month Kaplan-Meier estimates 19.4% and 17.5%; P=0.45). In the S-ICD group, 83 patients received at least 1 shock, versus 57 patients in the TV-ICD group (48-month Kaplan-Meier estimates 19.2% and 11.5%; P=0.02). Patients in the S-ICD group had a total of 254 shocks, compared with 228 shocks in the TV-ICD group (P=0.68). First shock efficacy was 93.8% in the S-ICD group and 91.6% in the TV-ICD group (P=0.40). The first antitachycardia pacing attempt successfully terminated 46% of all monomorphic ventricular tachycardias, but accelerated the arrhythmia in 9.4%. Ten patients with S-ICD experienced 13 electrical storms, versus 18 patients with TV-ICD with 19 electrical storms. Patients with appropriate therapy had an almost 2-fold increased relative risk of electrical storms in the TV-ICD group compared with the S-ICD group (P=0.05).

CONCLUSIONS: In this trial, no difference was observed in shock efficacy of S-ICD compared with TV-ICD. Although patients in the S-ICD group were more likely to receive an ICD shock, the total number of appropriate shocks was not different between the 2 groups. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.


Original languageEnglish
Pages (from-to)321-329
Number of pages9
Issue number5
Publication statusPublished - Feb 2022

External IDs

Scopus 85123968708



  • Aged, Arrhythmias, Cardiac/diagnosis, Defibrillators, Implantable/standards, Female, Humans, Male, Middle Aged, Prospective Studies, Treatment Outcome