[Evaluation of myocardial ischemia using Holter monitoring]

To establish the diagnostic criteria for myocardial ischemia, Holter monitoring and coronary angiography were performed on 46 cases (24 males (51.8 +/- 9.3 years), 22 females (47.5 +/- 10.5 years)). These patients were retrospectively selected from about 12000 patients who had the Holter monitorings from 1980 to 1993. The criteria for the entry were 1) reliable trend recordings of heart rate and 2) reliable recording of ST trend with accurate 1 mV calibration. The coronary stenosis greater than 75% in diameter was considered to be significant. Results were as follows: 1) ST trend pattern was classified into typical type, atypical type and box type. There were no significant differences in the incidence of typical and atypical types between ischemic and nonischemic groups, 2) Diagnostic accuracy of the criteria for myocardial ischemia, that is, the horizontal or downsloping ST segment depression with 0.1 mV at the point of 80 msec from the J point lasting for 1 minute, was higher in male than in female: the sensitivity was 93.3% and the specificity was 55.6% for men respectively, whereas the sensitivity was 66.7% and the specificity was 37.5% for women respectively, 3) Diagnostic accuracy of the ST/Heart rate ratio was 80.0% for the sensitivity and 64.7% for the specificity, indicating an improvement of specificity, 4) Maximal ST segment depression was accompanied by pain by 88.8% in true positive group (significant ST segment depression with significant coronary stenosis), whereas that was 28.6% in false positive group (significant ST segment depression without significant coronary stenosis), 5) Comparison of the degree of maximal ST segment depression, duration and frequency between computer and manual measurement showed a good correlation for the degree of maximal ST segment depression, whereas the duration and the frequency showed no significant correlations. The above results suggest that combined evaluation of the ST segment depression criteria (downsloping or horizontal ST segment depression greater than 1 mm at the point of 80 msec from the J point) and the ST/Heart rate criteria (1.4 microV/beats/min) is useful for the diagnosis of myocardial ischemia using Holter monitoring.