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). CONCLUSION: 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.