Assessment of autonomic function in patients with acute myocardial infarction or diabetes mellitus by heart rate variability, ventricular late potential and QT dispersion.

To compare the efficacy and sensitivity of heart rate variability (HRV), QT dispersion (QTd) and ventricular late potential (VLP) examination in judging autonomic function. Thirty three patients with acute myocardial infarction (AMI) and 33 patients with diabetes mellitus (DM), all of whom were diagnosed with autonomic neuropathy determined by a standard test of cardiovascular autonomic function, were examined by HRV (timing domain methods), QTd and VLP. Thirty three normal individuals served as controls. The mean SD of the normal R-R interval (SDNN) in both the AMI and DM groups was significantly less than that in the control group (p< 0.01); and of course, the QTd of these groups was significantly greater than that of the controls (p< 0.01). The VLP positive rate of the AMI and DM groups were much higher than that of the control group (p< 0.001). SDNN was shown to be significantly negatively correlated to QTd (r= -0.45); and significantly negatively correlated to VLP (r= -0.47); QTd was shown to be positively, though not significantly, correlated to VLP (r=0.48). QTd could be looked as sieving index; HRV could be looked as routine examination of cardiovascular autonomic function, especially SDNN; the combination of HRV and VLP could improve the accuracy of diagnosis.