Implantable defibrillators with enhanced detection algorithms: detection performance and safety results from the PainFree SST study

Christian G Wollmann, Thomas Lawo, Volker Kühlkamp, Rüdiger Becker, Claudio Garutti, Troy Jackson, Mark L Brown, Harald Mayr

Research output: Journal article (peer-reviewed)Journal article

17 Citations (Scopus)


BACKGROUND: Implantable defibrillators (ICD) are highly effective in reducing arrhythmia-related mortality. ICD shock therapy has been shown to increase psychological distress, health care utilization, and is associated with increased mortality. The Protecta ICDs (Medtronic Inc., Minneapolis, MN, USA) have algorithms designed to reduce unnecessary and inappropriate shock therapy.

METHODS AND RESULTS: The PainFree SmartShock™ Technology (PainFree SST) study is a prospective, multicenter, clinical trial with two consecutive phases, a premarket phase safety study and a postmarket phase effectiveness study. We report the results of the PainFree SST safety study. The premarket phase aimed to investigate safety in the first year postimplant, and to determine if the novel algorithms (T-wave discrimination, right ventricular lead noise discrimination and confirmation+) affect appropriate ventricular fibrillation (VF) detection. Patients (total: n = 246 [male 78%, mean age 63 year, primary prevention indication in 76%]) were implanted either with a Protecta XT dual-chamber ICD (n = 114 [46%]) or a defibrillator with cardiac resynchronization therapy (n = 132 [54%]). Appropriate VF detection was measured during VF induction at implantation when the novel algorithms were programmed ON. A two-second delay in VF detection was classified as clinically significant. No delay in VF detection was observed with all algorithms programmed ON. No unanticipated serious adverse device effects occurred during first year postimplant.

CONCLUSION: The results of the premarket phase of the PainFree SST trial demonstrate the safety of the Protecta XT defibrillators. Detection of induced VF was not delayed with SmartShock™ algorithms ON.

Original languageEnglish
Pages (from-to)1198-1209
Number of pages12
JournalPACE - Pacing and Clinical Electrophysiology
Issue number9
Publication statusPublished - 01 Sept 2014


  • Aged
  • Algorithms
  • Anticoagulants/therapeutic use
  • Arrhythmias, Cardiac/physiopathology
  • Defibrillators, Implantable
  • Electrocardiography, Ambulatory
  • Equipment Safety
  • Female
  • Humans
  • Male
  • Middle Aged
  • Patient Safety
  • Product Surveillance, Postmarketing
  • Prospective Studies
  • Risk Factors
  • Sensitivity and Specificity
  • Treatment Outcome


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