ABSTRACT
Background: Altered cardiovascular autonomic nerve function with impaired sympathovagal balance is found in rheumatoid arthritis (RA). Heart Rate Variability (HRV) analysis is an important tool for assessment of autonomic nerve activity. Objective: To assess cardiac autonomic nerve function status in patients with Rheumatoid arthritis (RA) by time domain measures of HRV. Methods: This cross sectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from January to December 2010. Sixty female RA patients, age range 18-50 years were constituted study group enrolled from the Out- patient Rheumatology Wing, Department of Medicine, BSMMU. Age matched thirty apparently healthy females were studied as control. Time domain measures of Heart Rate Variability (HRV) such as Mean RR intervals, Mean HR, SDNN, RMSSD, NN50% and PNN 50% were recorded for 5 minutes by a Polygraph machine to observe cardiac autonomic nerve function activity. Data were analyzed by independent sample t test. Results: Mean R-R interval, SDNN, RMSSD, PNN50%, NN50% were significantly lower (p<0.001) but heart rate was significantly (P<0.001) higher in rheumatoid arthritis patients. Conclusion: Cardiac autonomic nerve function is impaired and characterized by reduced resting parasympathetic activity in female Rheumatoid Arthritis patients.
ABSTRACT
Background: Cardiovascular complications are common in hypothyroids .Time domain measures of HRV is useful to determine the cardiac autonomic regulation by assessing sympathovagal balance. Objective: To assess the cardiac autonomic nerve function activity by time domain measures of heart rate variability in patients with hypothyroidism. Methods: This cross sectional study was carried out in the Department of Physiology, Banghabandhu Sheikh Mujib Medical University between July 2008 to June 2009 on 60 female patients with hypothyroidism aged 30-50 years. 30 age matched apparently healthy euthyroid subjects were also studied as control. Hypothyroid patients were divided into 2 subgroups ,one group includes patients on their 1st day of diagnosis, before starting of treatment and another group includes patients with medication for 12-18 months. The patients were selected from the Out Patients Department of Endocrinology Wing BSMMU. Serum TSH and FT4 levels of all subjects were measured by AxSYM system. For assessing HRV by time domain method, mean R-R interval, mean heart rate, SDNN, RMSSD and variance were measured by a Polyrite. For statistical analysis, Independent Sample t test and One Way ANOVA were used. Results: The mean serum TSH was significantly higher and FT4 was significantly lower (p<0.001) in newly diagnosed hypothyroids than those of control and treated group. In untreated hypothyroid patients the mean values of heart rate, SDNN , RMSSD,variance were found significantly (p<0.001) lower in comparison to both control and treated patients. No significant difference in these hormonal levels and all these time domain measures were found between control and treated group. Conclusion: This study concludes that decrease parasympathetic nerve activity may be a consequence of hypothyroidism, if not treated properly.
ABSTRACT
Background: Essential hypertension may be associated with altered cardiovascular autonomic nerve function. Heart Rate Variability (HRV) analysis is an important tool for quantitative measurement of autonomic nerve activity. Objective: To assess the cardiac autonomic nerve function status in essential hypertension by analyzing time domain measures of heart rate variability. Methods: This cross sectional study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University from 1st July 2008 to 30th June 2009.For this purpose, 60 hypertensive male patients with age ranged between 40-60 years (group B) were enrolled from the Out Patient Department of Cardiology, BSMMU, Dhaka. Based on treatment received, hypertensive patients were subdivided into group B1 i.e.untreated patients on their 1st day of diagnosis and group B2 i.e.patients with antihypertensive therapy. For comparison, 30 age & sex matched apparently healthy normotensive subjects (group A) were also studied as control group. Time domain measures of Heart Rate Variability (HRV) such as Mean RR intervals, Mean HR, SDNN & RMSSD were assessed by a Polygraph machine to observe both sympathetic and parasympathetic nerve function status. For statistical analysis of data, Independent sample t-test, One-way ANOVA test, were used as applicable. Results: Mean R-R interval SDNN and RMSSD were significantly (P<0.01) lower but mean heart rate was significantly (P<0.01) higher in untreated hypertensive patients than those of normotensive subjects. But differences in all these 4 parameters when compared between control and treated hypertensive patients were found statistically non significant. Conclusion: Impaired cardiac autonomic nerve function characterized by sympathetic overactivity may occur in hypertensive patients.