Heart rate variability and its circadian rhythm in patients with type 2 diabetes mellitus complicated with coronary heart disease

Objective To investigate the heart rate variability(HRV) and its circadian rhythm in patients with type 2 diabetes mellitus(T2DM) complicated with coronary heart disease(CHD).Methods Thirty patients with T2DM complicated with CHD were classified as group A,32 patients with T2DM as group B and 30 healthy subjects as control group C.The 24 h time domain and frequency domain parameters were recorded by holter electrocardiogram(ECG).The parameters of HRV were compared in 3 groups and the day and night HRV in patients with T2DM complicated with CHD was also studied.Results The parameters of HRV of the patients in group B were significantly lower than those of the group C(all P0.05).The parameters of HRV in group A were also significantly lower than those of the group B and C(all P0.05),but there was no significant difference in the day and night HRV time domain parameters between the three groups(all P0.05).Conclusion The cardiovascular autonomic nerve damage in patients with T2DM complicated with CHD is more severe than that of the patients with T2DM.In the patients with T2DM complicated with CHD,the parameters of HRV are lowered and the circadian rhythms are lost.Checking HRV in patients with T2DM complicated with CHD is helpful in the early discovery of high risk patients.