Correlation between cardiac enzyme elevation and the duration of cardiopulmonary resuscitation

Cardiovascular disease is the leading cause of death in the United States. Acute myocardial infarction (MI) is defined as necrosis of myocardial cells. Several studies have shown that cardiac markers are elevated after successful cardiopulmonary resuscitation (CPR) due to physical as well as electrical trauma. Correlation has never been established between an elevation in cardiac markers and patient age, the amount of trauma induced during resuscitation, or the duration of chest compression. Previous studies have determined that cardiac troponin (cTnl) is the most sensitive marker in cardiac injury. In this study, we hypothesized that the duration of CPR and the patient's age had a direct correlation with cardiac injury demonstrated as an elevation of cTnl. We analyzed retrospectively 81 patients that underwent successful CPR in an in-hospital setting. 13 patients were excluded from the analysis due to positive cTnl prior to cardiac arrest. Duration of CPR, as well as cTnl levels before and after cardiac arrest were recorded and analyzed in the remaining 68 patients. Patients with a negative cTnl after successful CPR (n=30) were stratified into Group A. The remaining patients (Group B) had a positive cTnl ranging from 2.2-31 ng/ml. The mean age and the mean duration of CPR in minutes were calculated and compared using t-Test analysis. There was no statistical difference in age between Group A and Group B. Patients in Group A had a mean CPR duration of 12.2 minutes, while patients in Group B had a mean CPR duration of 19.8 minutes (p < 0.02). We found that the duration of cardiopulmonary resuscitation was positively associated with the elevation of cardiac markers.