Biomedical subjects
G S Wander
Publications and source records attributed to G S Wander.
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.
Epidemiology of coronary heart disease in a rural Punjab population--prevalence and correlation with various risk factors.
An epidemiological study to find out the prevalence of coronary heart disease (CHD) and the influence of risk factors on the prevalence of CHD in a total rural community of Punjab was conducted in Pohir, situated near Ludhiana. A total of 1100 individuals (623 males and 477 females) out of a possible 1617 individuals (> 30 yrs) living in 3 villages were studied. In each case a detailed history, physical examination and a 12 lead electrocardiogram (ECG) were recorded. Samples for blood sugar and serum cholesterol were taken. By Epstein's criteria of ECG (using the Minnesota coding), the prevalence of CHD was 30.8/1000, being higher in women (37.7/1000) than in men (25.6/1000). By a clinical judgement method considering history, ECG and treadmill testing (TMT) collectively, prevalence was 31.8/1000, being still higher in women (33.5/1000) than in men (30.5/1000). The prevalence of various risk factors like hypertension, smoking, hypercholesterolemia and diabetes was found to be 14.5%, 8.9%, 7.0% and 4.6% respectively. Of the various risk factors tested, hypertension, hypercholesterolemia and a positive family history showed an association with CHD. Only 38% of patients with CHD, 37% of the hypertensives and 52% of the diabetics were aware of its presence. The knowledge in the general population about risk factors causing CHD is poor.
Should beta-blockers be withdrawn in post-myocardial infarction patients before treadmill test?
In most patients of myocardial infarction, beta-blockers are used for secondary prophylaxis and a treadmill test is required for risk stratification. To study the effect of oral beta-blockers on interpretation of treadmill test, 54 consecutive patients were subjected to treadmill test four to six weeks after myocardial infarction. Fourteen patients with strongly positive treadmill test were referred for coronary angiography. Treadmill test was repeated in 37 patients 72 hours after withdrawal of beta-blockers. The peak exercise heart rate was significantly different while off and on beta-blockers (148 +/- 13 bpm vs 124 +/- 14 bpm, respectively; p < 0.01). The test was negative on both the occasions in 17 patients. On stopping beta-blockers, the negative test became mildly positive in five and strongly positive in six patients. The mildly positive test became strongly positive in four patients and remained almost unchanged in five. In 10 patients there was conversion of negative or mildly positive treadmill test into strongly positive result after withdrawal of beta-blockers. Thus the risk stratification changed significantly in 27 percent patients. It is suggested that beta-blockers can and should be withdrawn in post-MI patients before doing treadmill test.