[Clinical value of multiple praecordial chest leads for evaluating the course of acute anterior myocardial infarction (author's transl)].

Percordial ST-segment mapping using an improved 48-lead system was evaluated 2-to-3-hourly in 322 single measurements on 24 patients with acute anterior myocardial infarction. Changes in the sum of ST-elevation (capital sigma ST) or in the number of leads with ST-elevation (NST) could be distinguished in two different phases: an initial rapid increase and decrease in capital sigmaST and NST was followed after 6 to 12 hours, by a more plateau-like course, which exhibited, especially in uncomplicated cases, only slight further changes. During the initial phase, marked differences in the maximal rate of decrease were observed for capital sigma ST and NST. In this phase, interpretation of therapeutical interventions using changes of capital sigma ST or NST as reference is therefore very critical. However, during the second plateau-like phase, extension of myocardial necroses is significantly associated with a new steep increase in capital sigma ST. Thus precordial mapping is suitable for rapid and sensitive detection of infarct extension in patients with anterior myocardial infarction. The development of pericarditis or bundle-branch block, which principally can disturb the evaluation of capital sigma ST and NST, occurred only sporadically in a few patients and therefore caused no major problems.