Acute myocardial infarction in cardiac transplant recipients.

To characterize the clinical and pathologic features of acute myocardial infarction (AMI) in cardiac transplant recipients, 22 Stanford patients who had 25 documented infarcts at a mean of 3.86 years after transplantation were reviewed. Symptoms included chest pain (2), arm pain (3), weakness (16), dyspnea (11) and palpitations (8). Three episodes were clinically silent, detected only as new electrocardiographic changes during routine follow-up. Of 18 patients hospitalized with symptoms, only 7 had electrocardiographic changes of typical Q-wave AMI; 5 had nonspecific ST-segment changes and 2 had no documented changes. Two had old Q waves. Twelve of the 18 were misdiagnosed at admission as having infection or congestive heart failure. Serial creatine phosphokinase levels were obtained in 13 patients, and values were elevated in 8. Six of 25 AMI episodes were associated with development of congestive heart failure and 4 others led to development of cardiogenic shock. Seven patients died during the acute phase of infarction, 12 were retransplanted from 2 days to 6 months after infarct and 1 died suddenly after discharge. Two healed myocardial infarctions of unknown duration were found at autopsy or on explantation in patients not clinically suspected of having an AMI. All infarcts occurred in patients known to have angiographic evidence of transplant coronary artery disease, based on annual coronary arteriography. At autopsy or explantation all hearts were found to have characteristic diffuse concentric coronary artery narrowing, and 4 (18%) had an unusual pattern of multiple foci of nontransmural AMI.(ABSTRACT TRUNCATED AT 250 WORDS)