Use of body surface electrocardiographic mapping to localize the asynergic site in previous myocardial infarction.

Body surface electrocardiographic (ECG) maps of myocardial infarction were analyzed using the departure mapping technique, which represents the abnormal potential distribution out of normal ranges. Body surface ECG mapping using 87 leads was performed on 65 patients with previous myocardial infarction and on 40 normal volunteers. Potential departure maps at 10, 20, 30, 40, and 50 msec after the onset of QRS were constructed; each map indicated, if present, the area of abnormal decreased potential that is more than 2 standard deviations from the normal range (-2 SD area). In patients with myocardial infarction, the appearance time and the location of the -2 SD area were specific for the sites of left ventricular asynergy; the sensitivity and specificity were 86% and 100% for the asynergy of segment 2 (20 msec, on the upper left anterior chest), 87% and 97% for segment 3 (30 msec, on the middle anterior chest), 86% and 80% for segment 4 (20 or 30 msec, on the lower right anterior chest), and 88% and 90% for segment 5 (30, 40, or 50 msec, on the middle back), respectively. The sensitivity of these criteria was better than that of 12-lead ECG, while the specificity was comparable. In the analysis of body surface ECG mapping data, departure maps aid in depicting abnormalities and in making an accurate assessment. Body surface ECG mapping can be used to improve the diagnostic ability of ECG to detect myocardial infarction.