Effect of posture in immediate post-exercise period on ischaemic ST-changes during stress electrocardiographic testing.

In this study of stress testing, the posture in which patients were put had effect on heart rate, blood pressure, rate pressure product and ST-segment depression integral in the recovery phase. The systolic blood pressure in recovery phase of stress testing fell more rapidly towards normal pre-exercise value in sitting (Group I) than in lying down (Group II) posture (p < 0.05) from 2nd to 5th minute. The changes in heart rate were less and slower in lying posture than with sitting up. The decrease in rate pressure product (RPP), a determinant of myocardial oxygen requirement was lower in lying down than in sitting up posture (p < 0.05) from 2nd to 5th minute of recovery. Consequently, ST-depression, a marker of ischaemia was more marked in lying down than sitting up. The ST-depression integral was 4.15 +/- 1.2 and 7.10 +/- 1.65 in 2nd minute in group I and group II respectively, and the difference was statistically significant in 2nd, 7th (p < 0.05) and 8th minute (p < 0.01) of recovery. These changes are important in interpretation of results of exercise testing.