The electromechanical interval in normal subjects and after myocardial infarction

The electromechanical interval (EMI) was measured in 25 normal males, 56 male patients with a myocardial infarction and 6 patients with a ventricular aneurysm. In the normal subjects the EMI was found to be unrelated to the heart rate but the isovolumic contraction time was inversely related to the heart rate. The EMI was increased after myocardial infarction but this increase did not occur in patientswho had a non-transmural infarction when they had not had any previous myocardial infarction. The increase was more marked in the patients with a ventricular aneurysm. It is suggested that the prolongation of EMI is due to areas of abnormal left ventricular wall movement and that this effect may be a useful aid to the diagnosis of ventricular aneurysm.