Women with subclinical hypothyroidism exhibited reduced heart rate variability and 47% showed abnormal sympathetic autonomic tests compared to controls.
Does subclinical hypothyroidism alter autonomic function and heart rate variability in women compared to healthy euthyroid controls?
Women with subclinical hypothyroidism exhibit significant autonomic dysfunction, predominantly sympathetic, which may serve as an early marker for increased cardiovascular risk.
Absolute Event Rate: 0% vs 0%
Objectives: The objective is to evaluate the autonomic function tests to assess cardiovascular risk in women with subclinical hypothyroidism (SH). Materials and Methods: Women aged 20–55 years attending the All India Institute of Medical Sciences outpatient department with SH were recruited for the study. Women with euthyroid state were taken as controls (age-matched). The subjects are assigned into 2 groups based on clinical features and laboratory investigations: Group I: 58 women with SH, Group II: 50 healthy women with euthyroid state (controls). Resting electrocardiography (ECG) recording was obtained for 5 min for generating R-R interval series from selected lead II for measurement of heart rate variability (HRV), and the bedside battery of tests for autonomic reactivity was performed. Results: HRV indices measured from 5-min ECG recordings showed a decrease in HRV parameters in Group I females compared to the control group, reflecting lower autonomic nervous system activity. 47% ( n = 27) of females with SH had abnormal sympathetic autonomic tests. 29% ( n = 17) of females with SH had abnormal heart rate response to deep breathing and standing, considered as parasympathetic dysfunction. Conclusion: Our study revealed that women with SH had decreased HRV with reduced sympatho-vagal tone and autonomic reactivity. Sympathetic dysfunction was predominant in SH, although parasympathetic dysfunction was also seen.
Ganji et al. (Tue,) reported a other. Women with subclinical hypothyroidism exhibited reduced heart rate variability and 47% showed abnormal sympathetic autonomic tests compared to controls.