Lowering of triiodothyronine level in blood plasma in patients with acute myocardial infarction: Relationship with early left ventricular dilatation

Levels of triiodothyronine and thyroxine in venous blood were determined by radioimmunoassay in 67 patients with Q-wave myocardial infarction and results were correlated with data of two-dimensional echocardiography, In all patients these studies were performed on days 10-14 and in 37 patients - on day one of infarction. It was found that in subacute period of infarction 44,8% of patients had syndrome of euthyroid pathology ("sick euthyroid syndrome") with pronounced lowering of triiodothyronine level, normal level of thyroxine, and left ventricular dysfunction. Formation of this syndrome was related to development of predominantly systolic early cardiac dilatation and sustained left ventricular dysfunction.