title: Prognostic evaluation of the troponin I elevation after multiple spontaneous shocks of the implantable cardioverter/defibrillator.
abstract: BACKGROUND
  Multiple shocks of the implantable cardioverter/defibrillator (ICD) can cause myocardial injury, contributing to the progression of underlying heart disease. The aim was to evaluate if the elevation of troponin I after multiple ICD shocks has impact on the prognostic of these patients.
  
  
  METHODS
  We evaluated patients with multiple ICD shocks (>3 shocks) in the last 24 hours. Troponin I was measured around 12 hours after the last shock. After this episode, these patients were followed; and events of death or heart failure hospitalization were recorded.
  
  
  RESULTS
  Twenty-six patients were included in the study. Elevation of troponin I occurred in 16 patients (62%), who had received a higher number of shocks (14 ± 9 vs 7 ± 4, P = .03) and greater cumulative total voltage (455 ± 345 J vs 141 ± 62 J, P = .03) compared to the group without elevation of this biomarker. We observed a positive correlation between troponin I and number of shocks (r = 0.70; P = .0001). Patients with troponin I elevation after multiple ICD shocks had higher risk of death or heart failure hospitalization (hazard ratio, 7.0; 95% confidence interval, 1.2-16.0; P = .03) compared with the group without elevation of this biomarker. After adjustment for age, sex, and number of shocks, the elevation of this biomarker remained as predictor of these events (hazard ratio, 16.0; 95% confidence interval, 1.7-151.0; P = .02).
  
  
  CONCLUSIONS
  A large proportion of patients with multiple ICD shocks have troponin I elevation, and these patients have a higher risk of death or hospitalization due to heart failure.
authors.affiliation: Division of Emergency Medicine, University of São Paulo Medical School at Ribeirão Preto, SP, Brazil. Electronic address: chmirand@yahoo.com.br.
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: Miranda
authors.affiliation: Division of Cardiology of the Department of Internal Medicine, University of São Paulo Medical School at Ribeirão Preto, SP, Brazil.
authors.forename: André
authors.initials: A
authors.lastname: Schmidt
authors.affiliation: Division of Emergency Medicine, University of São Paulo Medical School at Ribeirão Preto, SP, Brazil.
authors.forename: Antônio
authors.initials: A
authors.lastname: Pazin-Filho
mesh_terms: D015415:Biomarkers / Q000097:blood; D017147:Defibrillators, Implantable / Q000009:adverse effects; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000175:diagnosis* / Q000401:mortality; D006335:Heart Injuries / Q000097:blood / Q000209:etiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I