Abstract
The left ventricular wall motions in 53 patients with myocardial infarction and 14 normal subjects were studied by echocardiography and B-scan imaging (ultrasono-cardiokymography, ultrasono-cardiotomography).
(1) Abnormal left ventricular wall motions corresponding to the electrocardiographic sites of infarction were seen in the echocardiograms in 80% of total patients and 100% of acute cases. Exaggerated wall motion in opposing noninfarcted areas was seen in 50% of acute cases and 10% of old cases. Quantitative analysis of asynergy could be made by comparing PWE, SE and those ratios to EDD-ESD of infarcted hearts with those of normal hearts.
(2) In acute myocardial infarction, abnormal motions of left ventricular wall are marked in acute phase and diminished in extent gradually in recovery phase. But in some cases, echo-demonstrated segmental dyskinesis did not disappear in recovery phase, possibly due to the presence of irreversible myocardial damage.
(3) Echographic thickness of the infarcted wall was less increased than normals or was not increased during systole and decreased when bulged out in some cases, indicating the existence of necrotized muscle. Moreover, multiple echoes sometimes seen between endocardial and epicardial echoes of infarcted myocardium were considered to display the fibrosis of the infarcted myocardium.
(4) Abnormal echocardiographic motions of septum and posterior wall were observed in some cases who had no electrocardiographic abnormalities which suggest septal or posterior wall involvement. Echocardiography could detect another affected area of the left ventricle which could not be detected by electrocardiography.
(5) Echocardiography in combination with B-scan imaging (UCKG, UCTG) can detect not only the location, but also the size and extent of myocardial infarction.
(6) The results of this study indicate that echocardiography and B-scan imaging (UCKG, UCTG) are sensitive methods in detecting the size and location of asynergy and making a precise diagnosis of myocardial infarction. But it is necessary to distinguish abnormal septal and posterior wall motions observed in right ventricular volume overload, complete LBBB or PMD(COCM) from those of myocardial infarction.
