Applications of echocardiography in acute myocardial infarction.

Echocardiography has many attributes that are desirable for diagnostic and research studies in acute myocardial infarction patients. It does not alter the physiologic state being evaluated, is relatively inexpensive, and does not interfere with other hospital procedures. For these reasons, the test may be repeated frequently and used to monitor the changes after acute infarction. Useful information about left ventricular volume, diastolic pressure, and segmental wall motion may be obtained. Because echocarciographic estimates of stroke volume, ejection fraction, and velocity of circumferential fiber shortening are based on motion seen in only one "ice-pick" view of the heart, it is likely that they will be less reliable in patients with asynergy of contraction. Although a definite diagnosis of acute myocardial infarction cannot be made by echocardiography, abnormalities of wall motion may occur very early and support a clinical impression of infarction. An echocardiogram may also reveal changes suggesting ischemia or infarction (abnormal motion) in patients who have atypical chest pain and no other objective evidence of coronary artery disease.