Endocardial fibroelastosis with coronary artery thromboembolus and myocardial infarction.

We report a case of an 18-month-old male, born to a woman with third trimester febrile illness, who had a history of congestive heart failure and respiratory distress, cardiomegaly, and electrocardiographic (ECG) findings suggestive of cardiomyopathy and myocarditis. After gradual improvement in heart size and function with pharmacologic therapy, he developed a terminal episode of respiratory distress and cardiogenic shock, with ECG findings of an anterolateral infarct. At autopsy it was found that endocardial fibroelastosis with mural thrombi in the left ventricle had been complicated by thromboembolism to the left anterior descending coronary artery, resulting in transmural infarction of the anteroseptal region of the left ventricle. Myocardial infarction is a potential but unusual thromboembolic complication of endocardial fibroelastosis. A high index of suspicion for coronary artery thromboemboli should be maintained in pediatric patients with cardiomyopathy and suspected myocardial infarction.