[Vectorcardiographic image of localized paroxysmal ischemia]

The modifications of the vectocardiogram (VCG) have been studied during a positive effort test according to an original method using certain instant vectors of the Q-T interval. These "characteristic" vectors are determined by the peaks which appear on the curves of the spatial amplitude, the spatial speed and the curvature in function of time. The differences between the corresponding VCG values before and after effort have been studied by stepwise linear discriminating analysis (stepwise, jackknife). The 18 most important data for the classification have thus been determined. The discriminating function enables the separation of normal subjects from the ischaemic ones, with a total classification error of 22.88 per cent. In the group of patients with angina pectoris (without myocardial infarction), the classification error is of 25 per cent. It can be claimed that the VCG data obtained by discriminating analysis are characteristic of the VCG images provoked by localized, paroxysmal ischaemia of the myocardium.