Long term follow up study of prognostic significance of exercise duration during treadmill stress test in patients with stable coronary heart disease.

Treadmill stress tests provide useful noninvasive prognostic information in patients with coronary heart disease (CHD). The present study has prospectively analysed the long term prognostic value of exercise tolerance as measured by exercise time during treadmill stress test in 335 consecutive patients with stable CHD. 161 had exercise time of 6 minutes or less (mean 4.58 +/- 1.54 minutes) on a modified protocol (Group A) and 174 had exercise time of more than 6 minutes (mean 9.30 +/- 0.74 minutes)(Group B). Both groups were matched for major coronary risk factors (hypertension, smoking, diabetes and cholesterol levels) and type of drug therapy (betablockers, nifedipine, diuretics and aspirin). The patients have been followed up for upto 9 years with a mean of 6.28 +/- 2.99 years (Group A) and 7.87 +/- 1.98 years (Group B). Actuarial analysis shows that the overall survival after dropout due to death or coronary artery bypass surgery was significantly lower in group A [dropouts = 66 (41.0%)] than in Group B [dropouts = 19 (10.9%)] (Logrank test = 39.94, p < 0.001). The mortality was significantly higher in Group A with 58 deaths (36.0%) as compared to Group B with 16 deaths (9.2%) (x2 = 34.98, p < 0.001). The crude death rate was 5.73% per year in Group A as compared to 1.17% per year in Group B. The incidence of sudden deaths was also higher in Group A with 28(17.4%) instances as compared to 5(2.9%) in Group B (x2 = 19.85, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

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.