Heart rate recovery in exercise test in diabetic patients with and without microalbuminuria.

Background: Diabetes mellitus (DM) has a lot of complications such as macrovessel and microvessel disease. Another complication of DM is cardiac autonomic neuropathy (CAN), which have effect on automatic nervous system of heart. Failure in heart rate slowing after exercise is a presentation of this abnormality.

Methods: We selected diabetic patients and divided them to case and control group based on microalbuminuria. Case group comprised of diabetic patients with microalbuminuria and control group included those without microalbuminuria. Patients in both groups exercised on treadmill using Bruce protocol and heart rate was measured in first and second minutes in the recovery period.

Results: We selected 35 patients with microalbuminuria (case group) and 35 without microalbuminuria (control group) among diabetic patients. No statistically significant difference was seen in sex and age between case and control groups. Heart rate recovery in the first minute of recovery in the case and control groups did not show significant difference; but in the second minute of recovery, it was significantly higher in control group (97 ± 19.4 vs. 101.9 ± 12.4 beat per minute, P = 0.04).

Conclusion: In this study we evaluated the heart rate recovery or deceleration in diabetic patients with albuminuria and without microalbuminuria in recovery phase after exercise test. We found out that heart rate recovery at the second minute in the case and control groups has statistically significant difference but at the first minute, it did not.