Effect of Ramipril on Cardiac Autonomic Neuropathy in Patients With Type II Diabetes Mellitus

Background Cardiovascular autonomic neuropathy (CAN), an important form of DAN is caused by the impairment of the autonomic nerve fibers that innervate the heart and blood vessels and leads to abnormalities in cardiovascular dynamics. The earliest finding of CAN, even at the subclinical stage, is a decrease in heart rate variability (HRV). Objective The objective is to assess the effect of ramipril 2.5mg once daily on cardiac autonomic neuropathy in type II DM patients as an add-on to a standard antidiabetic regimen for a duration of 12 months. Materials and methods A prospective, open-label, randomized, parallel-group study was conducted on type II DM with autonomic dysfunction. Patients in Group A received tablet ramipril 2.5mg daily along with the standard antidiabetic regimen which consist of Tab Metformin 500mg twice a day and Tab Vildagliptin 50mg twice a day and group B received only the standard antidiabetic regimen for 12 months. Results Among 26 patients with CAN, 18 patients completed the study. After one year in group A, Delta HR value increases from 9.77±1.71 to 21.44±8.44 and the E:I ratio (ratio of the longest R-R interval during expiration and shortest R-R interval during inspiration) improved from 1.23±0.35 to 1.29±0.23 signifying significant improvement in parasympathetic tone. Results of the postural test showed significant improvement in SBP. Analysis of HRV by time domain method showed that the standard deviation of RR (SDRR) interval and Standard deviation of differences between adjacent RR interval (SDSD) value increased significantly in group A. Analysis of HRV frequency domain indices showed that LFP:HFP ratio improved after treatment in ramipril group indicating improvement in sympatho-vagal balance. Conclusion Ramipril improves parasympathetic component more as compared to sympathetic component of DCAN in type II DM. Ramipril could be a promising option having favorable long-term outcomes in diabetic patients especially when treatment begins at subclinical stage.