ABSTRACT
BACKGROUND: Autonomic dysfunction may contribute to cardiovascular morbidity in subclinical hypothyroid patients. It is controversial whether the abnormality exists in sympathetic or the parasympathetic function. It is also not known whether the severity of autonomic dysfunction is related to the degree of thyroid deficiency. DESIGN OF STUDY: Prospective case control. MATERIALS AND METHODS: Autonomic functions based on heart rate (HR) and blood pressure (BP) responses to various maneuvers were evaluated and scored in twenty two subclinical hypothyroid patients, 30-50 years and compared with twenty hypothyroid patients. Biochemical estimation of TSH, fT3, fT4, TPO antibody was done. RESULT: Sympathetic function abnormalities were seen in 82% subclinical hypothyroid patients and 85%hypothyroid patients when one test was abnormal. Parasympathetic dysfunction was also recorded in eight patients in both groups. When two abnormal tests were used as the selection criteria sympathetic function abnormality was observed in about 41% subclinical hypothyroid and 65% hypothyroid patients. There were no intergroup differences in autonomic functions, score and TPO levels. The TSH levels were not related to type or degree of autonomic dysfunction. Systolic BP in both groups and diastolic BP in hypothyroid patients were higher with lower thyroxine levels but the patients were normotensive. CONCLUSION: Autonomic dysfunction of comparable degree was seen in subclinical hypothyroid and hypothyroid patients. Sympathetic function abnormality was more common although decreased parasympathetic function reactivity was also present. These abnormalities were unrelated to TSH levels.
ABSTRACT
The etiology of essential hypertension includes increased oxidative stress. The role of antihypertensive drug amlodipine as an antioxidant and the benefit of addition of vitamin C, an antioxidant to antihypertensive therapy were studied. Forty male patients of essential hypertension were randomly divided into two groups and treated with 5 mg amlodipine. In addition one group also received 1000 mg vitamin C (as two 500 mg tablets) once daily for three months. Although blood pressure decreased in both groups, the systolic blood pressure in patients given vitamin C was less (126.4 +/- 7.47) compared to the other group (130.9 +/- 7.27). A decrease in malondialdehyde, an increase in erythrocyte sodium-potassium adenosine triphosphatase (Na(+) K(+) ATPase) and an increase in the superoxide dismutase levels were observed in both groups. The increase in SOD was statistically more in the patients given vitamin C in addition to amlodipine (0.1717 +/- 0.0150 compared to 0.152 +/- 0.0219 units/100 ml assay). In spite of the known antihypertensive, antioxidant activity, similarity in correcting endothelial dysfunction independently, giving the two drugs together and early introduction of vitamin C perhaps decreases oxidative stress and augments the antioxidant status. This may prevent further vascular damage due to oxidative stress, leading to a better prognosis in essential hypertension patients.
