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

ABSTRACT

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.