[Three infants with severe myocardial ischemia diagnosed by echocardiography: investigation of the cause of transient myocardial dysfunction].

We examined 3 infants with persistent pulmonary hypertension. They also showed signs of heart failure. The signs of cardiac dysfunction noted in the acute phase were resolved after treatment with catecholamines and vasodilators. Contrary to the general concept that transient myocardial dysfunction is secondarily caused by persistent pulmonary hypertension, left myocardial dysfunction accompanied pulmonary hypertension and was followed by right myocardial dysfunction. High blood concentration of thromboxane B2 was reported in 2 neonates with persistent pulmonary hypertension. We considered thromboxane A2 as a possible cause of coronary spasm, resulting in myocardial ischemia.