Impaired heart response to deep breathing in diabetic cardiacautonomic neuropathy: Importance of age- related normal range

Abstract

Introduction: Ewings battery of cardiac autonomic function tests provides a single value ignoring the decline in autonomic function with ageing. Objective: To derive age related normal range of heart rate response to deep breathing at six respiratory cycles per minute (HRV) from healthy subjects and estimate the prevalence of cardiac autonomic dysfunction in diabetes. Materials and Methods: HRV was measured in 207 subjects with type 2 diabetes mellitus and 141 healthy subjects matched for age and sex of diabetics. Abnormal scores had been defined as those more than 2 standard deviation below the mean value in controls. Results : Diabetics had lower HRV compared to controls in above the ? 40 years age groups (p 0.0001). Abnormal HRV expressed in beats per minute for different class intervals of age was: ? 40 years: 17; 41-50 years : 13; 51-60 years: 11; ? 61 years : 7.Abnormal HRV was observed in 11.59% of diabetics. Conclusion: Single value generates falls negative results among younger and falls positive results among older age groups. Thus age related normal range of HRV is appreciated in defining cardiac parasympathetic dysfunction in diabetics.