ST depression only on the initial 12-lead ECG: early diagnosis of acute myocardial infarction

Aims To compare the diagnostic ability of the 12-lead ECG with body surface mapping for early detection of acute myocardial infarction in patients pre senting with ST depression only on the 12-lead EGG. Methods and Results Fifty-four consecutive patients with chest pain <24h an d ST depression were recruited. A 12-lead ECG and 80-lead body surface map were recorded at presentation from which univariate and multivariate predic tion models of acute myocardial infarction were developed. Patients were ra ndomly divided into a training-set and a validation-set. Acute myocardial i nfarction occurred in 16/30 training-set and 8/24 validation-set patients. Univariate prediction of acute myocardial infarction by the 12-lead EGG, ba sed on the depth or numbers of leads with ST depression, was not improved b y assessment of ST elevation outside the conventional 12 leads using body s urface mapping. The optimum multivariate 12-lead ECG model developed in tra ining-set patients (six ST depression variables) had poor sensitivity (38%) although good specificity (81%) for acute myocardial infarction when teste d prospectively in validation-set patients. In contrast, the optimum body s urface mapping model developed in training-set patients (three isointegral or isopotential variables) achieved high sensitivity (88%) whilst maintaini ng good specificity (75%) for acute myocardial infarction when tested prosp ectively in validation-set patients. Conclusion Body surface mapping, when compared with the 12-lead EGG, may im prove the early diagnosis of acute myocardial infarction in patients presen ting with chest pain and ST depression only on the 12-lead EGG. (C) 2001 Th e European Society of Cardiology.