Prevalence and pattern of cardiac autonomic dysfunction in newly detected type 2 diabetes mellitus

Abstract

Cardiac autonomic functions were assessed in 145 consecutive recently detected type 2 diabetics. Ninety-nine healthy persons served as controls. Criteria for normalcy were, heart rate variation during deep breathing ≥15 beats/min, deep breathing expiratory to inspiratory R–R ratio ≥1.21, Valsalva ratio ≥1.21, sustained handgrip test ≥16 mm of mercury, cold pressor test ≥10, BP response to standing ≤10 mm of mercury and 30:15 R–R ratio on standing ≥1.04. An abnormal test was defined as the above parameters being <10 beats/min, <1.21, <1.21, ≤10 mm of mercury, <10, ≥30 mm of mercury and ≤1.0, respectively. A borderline test was defined as, heart rate variation during deep breathing 11–14, sustained handgrip test 11–15 mm of mercury, BP response to standing 11–29 mm of mercury and 30:15 R–R ratio on standing 1.01–1.03. Parasympathetic dysfunction was found in 44.2% and sympathetic dysfunction in 51.9% diabetics. Among healthy controls, these figures were 11.9% and 22.1%, respectively. Cardiac autonomic function was normal in 7.8% patients and 32.5% healthy controls.