Frequency of cardiac autonomic neuropathy in patients with type 2 diabetes mellitus reporting at a teaching hospital of Sindh.

OBJECTIVE: To determine the frequency of Cardiac Autonomic Neuropathy (CAN) in patients with type 2 Diabetes mellitus. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of Medicine, Liaquat University Hospital, Jamshoro, Hyderabad from December 2004 to April 2005. METHODOLOGY: Patients with type 2 Diabetes Mellitus (DM) of at least 10 years duration were selected. CAN was evaluated in terms of presence of resting tachycardia, loss of sinus arrhythmia and heart rate response to Valsalva maneuver by ECG. A R-R variation with respiration of > 15 beats per minute, 10-15 beats per minute and <10 beats per minute were taken as normal, borderline CAN and definitive CAN, respectively. QTc intervals were measured. The association between CAN, diabetic control and duration of diabetes were determined. RESULTS: The mean age was 53.62+/-8.30 years, with male to female ratio of 1:1. Mean values for known duration of diabetes and HbA1c were 14+/-3.5 years and 11.36+/-3.6 mg/dl respectively. Definitive and borderline CAN was noted in 30% and 40% patients respectively. Variability of heart rate with respiration was significantly related to duration but not to the control of diabetes (p < 0.05). QTc showed a significant correlation with the known duration of diabetes and heart rate variability with respiration (p < 0.05). Most of the patients had very bad glycemic status as evidenced by HbA1c. CONCLUSION: CAN is common in long-standing diabetics, specifically those treated with oral hypoglycemic agents than those with insulin. Intensive glycemic control is associated with a better cardiac autonomic nerve functions.