Anterior infarctional changes occurring during mid and late ventricular activation detectable by surface mapping techniques.

Abstract

This is a comparative body surface potential map study of 26 patients with a recent acute anterior myocardial infarction. The mean plus or minus two standard deviations (+/- 2 SD) for the voltage distribution was established at 5 msec intervals throughout the cardiac cycle in 30 normal subjects at each of 142 recording sites. Instances in which a patient's potential distribution fell outside the normal range were analyzed as to location, duration and intensity against the expected time course of ventricular activation. Only four patients had departures from the normal distribution confined to the Q time zone. Twenty patients had not only Q time zone abnormalities, but had areas of both positivity and negativity exceeding +/- 2 SD, which occurred well after 30 msec. Two patients with clearly documented diagnostic Q waves during the first few days of hospitalization had lost these findings by the date of body surface mapping. They did retain, however, departure map findings demonstrating significant abnormalities occurring between 30 and 60 msec after onset of ventricular activation. These changes occurring in the mid and late time zones of the activation sequence are not detectable by conventional electrocardiography or vectorcardiography, yet present a strikingly apparent finding by this technique of analysis and display.