Quantitative assessment of myocardial ischemia and necrosis by continuous vectorcardiography and measurement of creatine kinase release in patients.

The accuracy of the use of the maximal QRS vector difference to estimate myocardial infarct size irrespective of infarct location was compared with that of measurement of cumulative creatine kinase (CK) release. Sixty patients with acute myocardial infarction and a history of symptoms of less than 4 hr duration were followed for 24 to 72 hr with orthogonal vectorcardiography and CK release analysis. Spatial QRS vector differences were calculated between the first QRS complex recorded and subsequent QRS complexes at timed intervals. The QRS vector difference increased rapidly and reached a plateau at an average 12.1 hr after onset of symptoms, as compared with 34.0 hr for the cumulated CK release. In 42% of the patients a stepwise progression of infarct evolution was observed. Irrespective of infarct location the maximal spatial ST vector magnitude was related to the ultimate QRS vector difference (r = .80) and to the cumulative amount of CK released (r = .64). Furthermore, maximal QRS vector difference co...