Title: Effect of Hypothyroidism in Sympathovagal Status of Post Menopausal Women
Authors: Dr Tazkira Begum, Dr Aditya Ghosh, Dr S.M.I. Kabir, Dr Wasima Jahan
DOI: http://dx.doi.org/10.18535/jmscr/v4i2.78
Introduction: Post menopausal women are more prone to hypothyroidism as well as for cardiovascular ailments. Autonomic dysfunction or sympathovagal imbalance may contribute to cardiovascular morbidity in postmenopausal hypothyroid patients. Materials and Methods:Twenty healthy post menopausal women and twenty post menopausal women with hypothyroidism were enrolled for the study as control and cases respectively. Their autonomic status has been recorded as HRV for parasympathetic and hand grip test for sympathetic activity. Thyroid status was examined by RIA. Result: Comparison of TSH level with HRV in both control and cases are found to be insignificant (P value 0.4317 and 0.3429 respectively). But the comparison between TSH with handgrip exercise is found to be significant in case group (P value <0.0001 and 0.0077) for both for systolic and diastolic BP. Discussion: Though comparison between TSH with HRV of both control and cases are insignificant but the mean values of R-R interval of HRV decreases in cases than the control. So there is a vagal inhibition in hypothyroid group. Conclusion: Sympathovagal imbalance due to sympathetic activation and vagal inhibition occurs in hypothyroidism. Keywords: Autonomic nervous system, hand grip, HRV, hypothyroidism. 1. Foley CM, McAllister RM, Hasser EM. Thyroid status influences baroreflex function and autonomic contributions to arterial pressure and heart rate. Am J Physiol Heart Circ Physiol. 2001;280:2061–8. 2. Kahaly GJ. Cardiovascular and atherogenic aspect of subclinical hypothyroidism. Thyroid. 2000;10:665–79. [PubMed] 3. Akcakoyun M, Emiroglu Y, Pala S, Kargin R, Guler GB, Esen O. Heart rate recovery and chronotropic incompetence in patients of subclinical hypothyroidism. Pacing Clin Electrophysiol. 2010;33:2–5. [PubMed] 4. Galetta F, Franzoni F, Fallani P, Rossi M, Carpi A, Rubello D, et al. Heart rate variability and QT dispersion in patients with subclinical hypothyroidism. Biomed Pharmacother. 2006;60:425–30. [PubMed] 5. Sahin I, Turan N, Kosar F, Taskapan C, Gunen H. Evaluation of autonomic activity in patients with subclinical hypothyroidism. J Endocrinol Invest. 2005;28:209–13. [PubMed] 6. Cacciatori V, Gemma ML, Bellavere F, Castello R, De Gregori ME, Zoppini G, et al. Power spectral analysis of heart rate in hypothyroidism. Eur J Endocrinol. 2000;143:327–33 7. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Heart rate variability: Standards of measurement, physiologicalinterpretation and clinical use. Circulation 1996; 93: 1043–1065. 8. Pal GK. Integrated regulation of cardiovascular functions. In: Textbook of Medical Physiology, 1st ed, New Delhi, Ahuja Publications, 2007; 654–657. 9. Haensel A, Mills PJ, Nelesen RA, Ziegler MG Dimsdale JE. The relationship between heart rate variability and inflammatory markers in cardiovascular diseases. Psychoneuroendocrinology 2008; 33: 1305–1312. 10. Cacciatori V, Gemma ML, Bellavere F, CastelloR, De Gregori ME, Zoppini G, Thomaseth K, Moghetti P, Muggeo M. Power spectral analysis of heart rate in hypothyroidism. Eur J Endocrinol 2000; 143: 327–333. 11. Xing H, Shen Y, Chen H, Wang Y, Shen W. Heart rate variability and its response to thyroxine replacement therapy in patients with hypothyroidism. Chin Med J 2001; 114: 906–908. 12. Demers LM, Spencer C. The Thyroid: Pathophysiology and thyroid function testing. In: Tietz textbook of clinical chemistry and 252 Karthik et al 13. Motivala AA, Rose PA, Kim HM, Smith YR, Bartnik C, Brook RD, Muzik O, Duvernoy CS. Cardiovascular risk, obesity, and myocardial blood flow in postmenopausal women. J Nucl Cardiol 2008; 15: 510–517.Dis 2000; 181: 8462–8472.Abstract
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