Abstract During heart surgery, cardiac troponin I (cTn-I) measurement provides a tool to evaluate different cardioprotective techniques. To investigate myocardial protection during heart transplantation (HTx), cTn-I and creatine kinase (CK)-MB release was measured in 42 patients randomized to receving either continuous retrograde warm blood reperfusion or no reperfusion after cold cardioplegia. A significant linear correlation was found between donor heart ischemic time and peaks and the area under the curve of cTn-I and CK-MB release. In patients with an ischemic time longer than 90 min, cTn-I release was significantly lower in those receiving continuous retrograde warm cardioplegia than in controls. No significant difference was observed for CK-MB, tCK, and myoglobin. Our data suggest that the measurement of postoperative cTn-I release may provide a method to evaluate ischemic cardiac damage after HTx. When the ischemic time is longer than 90 min, warm retrograde blood cardioplegia provides better myocardial protection than no reperfusion.