[Reversible ischemic myocardial damage: clinical observation using two-dimensional echocardiography].

Abstract

Acute myocardial ischemia followed by protracted asynergy and subsequent resolution was defined as reversible ischemic myocardial damage. The purpose of this study was to confirm the existence of this entity and to illustrate the clinical features. The subjects consisted of 26 patients with typical acute myocardial ischemia who satisfied the above definition, and serial changes in left ventricular wall motion were observed by two-dimensional echocardiography. The left ventricle was divided into 11 segments and the movement was scored according to the dynamic behavior of each segment by five points ranging from normal (0) to dyskinesis (4), and evaluated semiquantitatively using the total score sum as the total asynergy score. Compared to the initial value, this score decreased to 57% after one week, 38% in two weeks, 22% in three weeks and 17% in four weeks. The asynergy persisted 23.7 +/- 13.5 days and ranged from two days to three months. The peak CPK ranged from 32 to 561 IU (mean 212 +/- 157 IU). Coronary arteriography revealed undisturbed flow of the responsible artery in both acute and chronic phases including four cases of successful PTCR. Comparison of the electrocardiographic changes and asynergy showed that diminished R wave amplitude, ST segment elevation and inverted T waves are frequently associated with persistence of asynergy, extensive asynergy can even occur in cases without a diminished R wave or abnormal Q wave and when asynergy resolves, ST segments tend to return to the baseline, but T wave inversion commonly persists. A transient Q wave was observed in 38% of the patients examined. The electrocardiogram became normal in an average of 111.3 +/- 75 days. In conclusion, there is a subgroup of reversible asynergy among cases of unstable angina pectoris or subendocardial infarction. The mechanism for this may be myocardial "stunning" following transient transmural ischemia. Recognition of this fact seems very important in the diagnosis and treatment of acute myocardial ischemia.