Body Surface Electrocardiographic Mapping in Inferior Myocardial Infarction

To determine the depolarization and repolarization time-integral patterns in patients with first acute inferior myocardial infarction, we acquired body surface potential maps in 28 men and eight women, ages 36-76 years, a mean of 76 hours after the onset of symptoms. Based on technetium-99m pyrophosphate myocardial scans, patients were divided into two groups. Group 1 included 22 patients with scintigraphic activity limited to the left ventricle who were considered to have exclusive left ventricular infarction, and group 2 included 14 patients with scintigraphic activity involving the right ventricle in addition to the left ventricle, considered to have both left and right ventricular infarction. Isointegral plots of the first 50% of the QRS complex (Q zone) were characterized by negative areas over the inferior torso with concomitant extension of positive areas to the superior precordium. Group 2 patients had greater leftward and superior extension of the negative inferior distributions than group 1 patients. Subtraction of the mean Q-zone map of group 1 patients from that of group 2 patients confirmed a mean area of difference over the right anterior-inferior torso. The average Q-zone integral value within this area of difference was 5.9 + 7.2 ,uV*sec (±+ SD) for group 1 patients compared with 1.7 + 5.2 ,V-sec for group 2 patients (p < 0.05). ST-segment isointegral maps revealed positive inferior distributions in all subjects; however, 29 patients also had abnormal negative ST-segment distributions over the precordium. The area of negative precordial values in group 2 patients extended further rightward and inferiorly compared with