To date approximately 50 rat hearts have been given cardioplegia containing nicardipine. It appears that nicardipine has a beneficial effect in protecting myocardium during ischemia at 37.5 degrees C, but not at 10 degrees C. The optimal dose of nicardipine for myocardial preservation has not yet been determined. These results are preliminary, and approximately 50 more animals will be required to complete the protocol.