Myocardial damage after high voltage electrical body injury is a serious and often life-threatening situation. The purpose of this pilot study was to identify early clinical predictors of myocardial damage in patients with high voltage electrical injury. Twenty-four patients with high voltage electrical injuries and no evidence of arc burns were evaluated. In 13/24 patients the diagnosis of myocardial damage was confirmed by total creatine kinase (CK) and creatine kinase MB (CK-MB) isoenzyme elevation (group A). In these patients the total CK range was 1373 to 52,544 mU/ml. In 11/24 patients CK-MB was negative (group B) indicating absence of myocardial damage. ECG changes occurred in 10/13 group A and 4/11 group B patients (p less than .095). No patient in either group gave a history suggestive of myocardial ischemia after the electrical injury. The pathways of electricity through the body, as mapped by a line drawn between the wound(s) of entrance and exit, were vertical in all group A patients, i.e., from upper to lower body segment, vs. 5/11 group B patients with evidence of a vertical pathway (p less than .003). Group A patients also had greater body surface burns (16.0 +/- 2.7%) vs. group B patients (4.0 +/- 1.6%, p less than .001). The presence of a vertical pathway and the magnitude of percent surface burns were found to be the most significant clinical predictors of myocardial damage in multiple logistic regression analysis (p less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)