Myocardial injury in children following resuscitation after cardiac arrest

Background: Myocardial dysfunction occurs immediately after successful cardiac resuscitation. Our purpose was to determine whether measurement of cardiac troponin I in children with acute out-of-hospital cardiac arrest predicts the severity of myocardial injury. Methods and results: This prospective, observational study was performed in the Pediatric Intensive Care Unit (PICU) on 24 patients following arrest, ranging in age from 8 months to 17 years. Troponin measurements were obtained on admission, and at 12, 24, and 48 h. Transthoracic echocardiograms were performed within 24 h after admission. Survival to hospital discharge was 29% (7/24). The mean age was 5.9±4.6 years for survivors and 4.2±5.3 years for non-survivors. The median (range) duration of cardiac arrest times for survivors was 6 min (3 to 63 min) versus 34 min (4 to 70 min) for nonsurvivors (P = 0.02). Survivors received 1.3±2.2 doses of epinephrine (adrenaline) compared with 2.9±1.6 doses for non-survivors (P = 0.02). Only one patient had ventricular fibrillation and defibrillation was unsuccessful. The ejection fraction for survivors averaged 73.2±11.2%, but for nonsurvivors only 55.4±19.8% (P = 0.04). Ejection fraction correlated inversely with troponin at 12 h (r = -0.54, P = 0.01) and at 24 h (r = -0.59, P = 0.02). Circumferential fiber shortening for survivors was 37.5±7.8 and 25.5±10.7% for nonsurvivors (P = 0.02). It also correlated inversely with troponin (r = -0.46, P = 0.03 for survivors and r = -0.65, P = 0.01, for nonsurvivors). Conclusion: After cardiac arrest and resuscitation in pediatric patients, the severity of myocardial dysfunction was reflected in troponin I levels.