In a retrospective analysis in 74 patients with coronary artery disease or no obvious heart disease, the value of "body surface potential mapping" for the identification of repolarization abnormalities was investigated compared to the standard 12-lead ECG. In patients with idiopathic ventricular fibrillation the number of extrema in the QRST integral map was significantly higher than in the control group (3.15+/-0.99 vs. 2.17+/-0.51, p<0.001) and the QT dispersion was also higher (0.10+/-0.03 vs. 0.07+/-0.01, p<0.001), whereas there was no difference between either group in the 12-lead ECG QT dispersion. In patients with coronary artery disease the number of extrema in the QRST integral map and QT dispersion were also higher compared to the control group, but there were no significant differences between patients with or without aborted sudden cardiac death.In conclusion, BSPM identifies repolarization abnormalities not detected by 12-lead ECG, thereby identifying a potential reason for cardiac arrest in patients without overt heart disease. The usefulness of this technique for risk stratification in patients with coronary artery disease remains to be elucidated.