[Ischemic heart disease detected by the standard deviation of the spatial QRS-T angle and by treadmill exercise test]

Beat-to-beat fluctuations of the spatial QRS-T angle, which are reported to be greater in patients with ischemic heart disease than in healthy subjects, are thought to be a helpful factor in diagnosing ischemic heart disease. In this study, we assessed the usefulness of the standard deviation of the spatial QRS-T angle per beat as an index of magnitude of the fluctuations. The subjects consisted of 27 patients with effort angina, 14 with vasospastic angina, 18 with the "chest pain syndrome" and 36 normal controls. The standard deviations of the spatial QRS-T angle were obtained for 10 consecutive stable beats at rest using Frank's orthogonal X, Y, Z scalar electrocardiogram. The results were compared with those of coronary angiography and exercise tolerance tests. Treadmill exercise tests were performed in all patients using Bruce's protocol to observe decreased ST levels and delta ST/HR indices. QRS-T angle deviation values were 8.10 +/- 8.64 degrees (mean +/- SD) in the effort angina group, 3.63 +/- 1.26 degrees in the vasospastic angina group, 4.13 +/- 1.70 degrees in the "chest pain syndrome" group, and 2.35 +/- 0.85 degrees in the normal control group; the groups of patients with heart disease showed significantly higher values (all p < 0.01) than did the control group. The effort angina group showed a significantly higher value than did the vasospastic angina group and the "chest pain syndrome" group (all p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)