Background: Nonlinear measure of heart rate variability (HRV) is an emerging tool to detect changes in cardiac autonomic nerve function (CANF) in transfusion dependent thalassemic (TDT) patients. Slow breathing exercise (SBE) can significantly improve HRV in health and various diseases. Objective: To observe the effect of slow breathing exercise (SBE) on non linear measures of HRV in TDT patients. Methods: This prospective interventional study was done in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka in 2018 on 60 male TDT patients aged 15-30 years. Thirty patients received conventional treatment and 30 patients performed slow breathing exercise along with the conventional treatment for 3 months. Age and sex matched 30 healthy control were enrolled. All subjects were followed up at baseline and after 3 months. Non linear (Poincare) HRV parameters were recorded by Power Lab 8/35 AD Instrument, Australia. For statistical analysis paired sample ‘ t’ test and independent sample ‘t’ test were used. Result: SD1, SD2 and SD1/SD2 were found significantly lower in TDT patients compared to healthy control at baseline. After 3 months of slow breathing exercise, significant increment of these parameters occurred with trend of improvement in cardiac autonomic nerve function in this group of patients. Conclusion: Slow breathing exercise may improve cardiac autonomic nerve function and sympathovagal balance in transfusion dependent thalassemic patients. J Bangladesh Soc Physiol. 2019, June; 14(1): 26-32

Background and Aim: Iron overload induced cardiac autonomic dysfunction is a major contributor to fatal arrhythmia and cardiac morbidity and mortality in transfusion-dependent thalassemia (TDT) patients. Slow breathing exercise (SBE) increases cardiac parasympathetic activity in health and disease. This study aimed to assess the effect of slow breathing exercise (SBE) on frequency domain measures of heart rate variability in TDT patients. Methods: This prospective interventional study was done on 60 diagnosed male TDT patients aged 15-30 years. They were subdivided into 30 patients with conventional treatment only and 30 patients performed SBE for consecutive 3 months along with the conventional treatment. Age and gender matched healthy control were also studied without SBE. HRV parameters were recorded by Power Lab 8/35. For statistical analysis paired t test and independent sample t test were done as applicable. Results: Total power (TP), High frequency power (HF), HFnu and Low frequency power (LF) were found significantly lower but LFnu and LF/HF were found significantly higher in TDT patients compared to healthy control at baseline. After 3 months of SBE, significant increment of TP, HF and HFnu and significant decrement of LF, LFnu and LF/HF occurred with trend of improvement in cardiac autonomic nerve function in TDT patients. No significant change in these parameters was found in patients without SBE after 3 months of follow-up. Conclusion: SBE can improve cardiac autonomic dysfunction by restoring cardiac vagal activity and reducing sympathetic activity with shifting of autonomic balance to parasympathetic predominance in TDT patients.