Troponin levels after ICD implantation with and without defibrillation testing and their predictive value for outcomes: Insights from the SIMPLE trial

Heart Rhythm. 2016 Feb;13(2):504-10. doi: 10.1016/j.hrthm.2015.11.009. Epub 2015 Nov 11.


Background: The Shockless IMPLant Evaluation trial randomized 2500 patients receiving a first implantable cardioverter-defibrillator (ICD)/cardiac resynchronization therapy-defibrillator device to have either defibrillation testing (DT) or no DT. It demonstrated that DT did not improve shock efficacy or reduce mortality.

Objective: This prospective substudy evaluated the effect of DT on postoperative troponin levels and their predictive value for total and arrhythmic mortality.

Methods: Troponin levels were measured between 6 and 24 hours after ICD implantation in 2200 of 2500 patients.

Results: A postoperative serum troponin level above the upper limit of normal (ULN) was more common in patients undergoing DT (n = 509 [46.4%]) than in those not subjected to DT (n = 456 [41.3%]; P = .02). After excluding patients with known preoperative troponin levels above the ULN, consistent findings were observed (42.1% vs 37.5%; P = .04). During a mean follow-up of 3.1 ± 1.0 years, the annual mortality rate was increased in patients with postoperative troponin levels above the ULN (adjusted hazard ratio [HR] 1.43; 95% confidence interval [CI] 1.15-1.76; P = .001) irrespective of DT or no DT. Likewise, patients with elevated troponin levels had a significantly higher risk of arrhythmic death (adjusted HR 1.80; 95% CI 1.23-2.63; P = .002). The rate of first appropriate ICD shock (adjusted HR 0.89; 95% CI 0.71-1.12; P = .32) or failed appropriate shock (adjusted HR 1.02; 95% CI 0.59-1.76; P = .95) was similar in patients with or without troponin elevation.

Conclusion: DT at the time of ICD implantation is associated with increased troponin levels, indicating subclinical myocardial injury caused by the procedure. Elevated troponin levels but not DT seem to predict clinical outcomes in ICD recipients.

Trial registration: NCT00800384.

Keywords: Defibrillation testing; Implantable cardioverter-defibrillator; Mortality; Troponin I; Troponin T.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cardiomyopathies / complications
  • Cardiomyopathies / mortality
  • Cardiomyopathies / therapy
  • Death, Sudden, Cardiac / prevention & control*
  • Defibrillators, Implantable / adverse effects*
  • Electric Countershock* / instrumentation
  • Electric Countershock* / methods
  • Female
  • Humans
  • Long QT Syndrome / complications
  • Long QT Syndrome / mortality
  • Long QT Syndrome / therapy
  • Male
  • Materials Testing / methods
  • Middle Aged
  • Mortality
  • Outcome Assessment, Health Care
  • Postoperative Complications* / blood
  • Postoperative Complications* / diagnosis
  • Predictive Value of Tests
  • Prognosis
  • Prosthesis Implantation* / adverse effects
  • Prosthesis Implantation* / methods
  • Troponin / blood*


  • Troponin

Associated data