Objective: Little is known about how the cardiac autonomic nervous function (CAN) changes with gradually increasing systolic blood pressure (SBP). This study investigated cardiac autonomic nervous function in diabetic patients and controls with different grades of SBP.
Methods and results: We measured heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS) by power spectral analysis in 118 Chinese type-2 diabetic patients and 137 age-matched controls. Subjects were further subdivided into 4 SBP groups. Results showed total HRV and BRS values were significantly lower in several diabetic SBP groups. Total HRV and BRS decreased with increasing SBP, with significant differences in the 140-159 mm Hg or 160-179 mm Hg groups compared with other groups of diabetic and control subjects.
Conclusions: We found that HRV and BRS can reflect cardiovascular autonomic dysfunction of diabetes when accompanied by hypertension. In our selected Chinese diabetic and control subjects, HRV and BRS parameters were influenced by gradually increasing SBP.