Prognostic value of profound ST segment depression during treadmill stress test in coronary heart disease: nine years follow-up study.

To define the prognostic significance of profound ST segment depression (greater than or equal to 3mm) during exercise test, 106 patients of definite coronary heart disease enrolled in a prospective study were followed for up to 9 years. Group A (56 patients) had profound (greater than or equal to 3mm) ST segment depression (3.56 +/- 0.74mm) and Group B (50 patients) had less than 3mm ST segment depression (1.23 +/- 0.35mm, P less than 0.01) during treadmill testing. Group A patients tolerated exercise for a lesser duration in comparison to group B patients (7.22 +/- 3.35 vs. 10.18 + 4.07 minutes, p less than 0.01). At the end of the study, 21 (37.5%) group A patients either died or underwent coronary artery bypass surgery as compared to 8 (16.0%) group B patients (p = 0.02). The difference in the incidence of cardiac deaths between the two groups was not statistically significant (19.6% in group A and 14.0% in group B). However, sudden deaths were significantly more common in group A as compared to group B patients (10 of 11 (90.9%) vs 4 of 7 (57.1%), p = 0.02). These data suggest that profound ST segment depression (greater than 3mm) during treadmill stress test indicates an adverse long term prognosis with the risk in particular, of sudden cardiac death.