Diagnostic features of body surface potential maps in patients with myocardial ischemia and normal resting 12-lead electrocardiograms

Abstract Body surface maps recorded from 35 ischemic patients with normal resting 12-lead electrocardiograms were compared with those obtained from 36 age- and sex-matched normal subjects. From instantaneous maps of each subject 187 variables were derived relating to the configuration (80 variables) and magnitude (104 variables) of the potential distribution and duration of the electrocardiographic intervals (3 variables). By using stepwise discriminant analysis we selected 3 variables whose linear combination enabled us to correctly allocate 91% of the study population (jacknife procedure; specificity 92%, sensitivity 91%). To substantiate the validity of the results the discriminant function was tested on a new independent population consisting of 27 ischemic patients and 54 normal subjects from another laboratory. A proper allocation was obtained in 86% of the cases (specificity 87%, sensitivity 85%). The large number of correctly classified ischemic patients and the repeatability of the results indicate that the adopted criteria are good markers of ischemic heart disease.