Detection of cardiac autonomic neuropathy in type II diabetic patients using heart rate recovery

Abstract

Background Cardiac autonomic neuropathy is one of the most insidious complications of diabetes mellitus. It can be detected by abnormality in heart rate recovery, which is defined as decline in heart rate within the first few minutes following a graded exercise stress test. Aim To detect cardiac autonomic neuropathy in type II diabetic patients using heart rate recovery. Patients and methods This study included 45 individuals, 30 diabetic patients in case group and 15 healthy individuals as a control. All participants underwent history taking, clinical examination, laboratory investigations (FBS, PPBS, HbA1c, kidney function test and liver enzymes), comprehensive transthoracic echocardiographic examination, 24 h Holter monitor and exercise ECG test to assess heart rate recovery. Results 30 diabetic patients (7 male and 23 females, with mean age 40±3.5 years) and 15 healthy individuals (4 males and 11 females with mean age 36±5.8 years) participated in this study. Cases group had significant increase in FBS, PPBS, HbA1c and serum creatinine compared to control group. Patients had significant decrease in PNN50, SDNN, LF and HF in the 24 h Holter monitoring as well as significant delay in heart rate recovery at 1st and 2nd minutes compared to control group. Glycemic control and duration of diabetes were the most predictors to abnormal heart rate recovery. Conclusion Heart rate recovery derived from exercise ECG test could be considered as an easy, low cost and widely available tool for detection of cardiac autonomic neuropathy.