Background: Several methods have been suggested for risk stratification of patients with unstable coronary syndromes. However, most of these are applied several days after hospital admission.
Methods: In this study we investigated the prognostic value of continuous ST-segment and QRS vector monitoring with computerized vectorcardiography (VCG), serial measurements of creatine kinase isoenzyme MB (CK-MB), predischarge stress testing and baseline data in patients with unstable angina pectoris or non-Q-wave infarction.
Results: During the 24 h VCG monitoring, 56 (29%) of the 195 patients had ST-vector magnitude (ST-VM) episodes of ischaemia. Seventy-four (38%) patients had a peak CK-MB value of 6 micrograms/l or higher during the 48 h sampling period. Several discrete variables were associated with death or non-fatal infarction at 1 year of follow-up in an univariate analysis. Among these were age > or = 65 years, female sex, St depression on the admission ECG or VCG monitoring, and elevated CK-MB levels, but neither the occurrence, duration nor intensity of chest pain. With Cox's proportional hazards regression analysis, ST-VM episodes on VCG monitoring were identified as independent markers of the risk of death (P = 0.013), death or non-fatal infarction (P = 0.035) and death, non-fatal infarction, unstable angina during the first year, or revascularization before hospital discharge (P = 0.005).
Conclusions: VCG monitoring of ischaemia provides independent prognostic information in unstable angina. High-risk patients can easily be identified within 24 h of hospital admission. Whether early intervention based on these criteria will result in improved prognosis remains to be shown in future studies.