Effect of coronary artery disease on parasympathetic cardiovascular reflexes in NIDDM patients

To evaluate the effect of coronary artery disease on parasympathetic cardiac reflexes in patients with non-insulin-dependent diabetes mellitus (NIDDM), we studied standard cardiovascular reflexes in 27 NIDDM patients with coronary artery disease (group 1) and in 21 NIDDM patients with no signs of coronary artery disease (group 2). Groups did not differ with respect to age, duration of diabetes, or presence of retinopathy. The mean +/- SD heart-rate variation in deep breathing was lower in group 1 than in group 2 (11.6 +/- 6.5 vs. 17.1 +/- 9.0 beats/min, P less than 0.05). Heart-rate variation was more often abnormally low (less than or equal to 10 beats/min) in group 1 than in group 2 (48 vs. 19%, P less than 0.05). Thus, the presence of coronary artery disease appears to modify cardiac parasympathetic reflexes in patients with diabetes mellitus and must be kept in mind when interpreting test results.