Low heart rate variability is a risk factor for sudden cardiac death in type 2 diabetes

Abstract 

The purpose of this study is to examine the association between sudden cardiac death (SCD) and heart rate variability (HRV) in subjects with and without type 2 diabetes and to determine whether low HRV can predict SCD in type 2 diabetes. Subjects were 8917 consecutively examined persons (3089 diabetic, and 5828 nondiabetic subjects) aged 35–69 years who underwent a 75g oral glucose tolerance test (OGTT) together with electrocardiography (ECG). HRV was calculated from the 12-lead ECG as the coefficient of variance for 100 R–R intervals (CV_R–R). During a median observation period of 5.2 years, SCD occurred in 56 subjects (33 diabetic, and 23 nondiabetic). Among diabetic subjects, mortality from SCD tended to be higher in subjects with a low CV_R–R (P=0.004). After adjustment for age, gender, systolic blood pressure, total cholesterol (TC), triglycerides (TG), BMI, ischemic ECG change, and smoking history, relative risk (RR) of SCD was 2.07 (95% CI 1.02–4.17) in diabetic subjects with a CV_R–R <2.2% compared with those with a CV_R–R ≥2.2%. Diabetic subjects with a CV_R–R <2.2% had significantly higher cumulative mortality from SCD than those with a CV_R–R ≥2.2% (P=0.007). In type 2 diabetes, a low CV_R–R carried an increased risk of SCD.

Keywords:  Type 2 diabetes mellitus, Heart rate variability, Cardiac sudden death