232 Journal of the College of Physicians and Surgeons Pakistan 2009, Vol. 19 (4): 232-235 INTRODUCTION The prevalence of Diabetes Mellitus (DM) for all age groups worldwide was estimated to be 2.8% in 2000 and 4.4% in 2030. The total number of DM is projected to rise from 171 million in 2000 to 366 million in 2030. The urban population in developing countries is projected to double between 2000 and 2030. The most important demographic change to DM prevalence across the world appears to be the increase in the proportion of people >65 years of age. 1 DM affects approximately 2.7 million people in Pakistan. Higher prevalence in women is observed in both urban and rural areas of Pakistan. One in four urban obese, over 40 years of age, is diabetic. 2 The prevalence of diabetes in Pakistan is 8.6%, 11.1% and 13.9% in the provinces of Baluchistan, NWFP and Sindh respectively. 3 The risk of cardiovascular events is at least 2-4 times higher in patients with diabetes. CAN is a result of damage to the vagal and sympathetic nerves. Clinical findings may include exercise intolerance, persistent sinus tachycardia, bradycardia, and no variation in heart rate during daily activities. Baroreceptor disease contributes to the supine hypertension. In a patient with type-1 DM, an autonomic imbalance may result in a prolonged QT interval on the ECG, which may predispose the patients to the life-threatening cardiac arrhythmias and sudden death. CAN reduces appreciation of ischemic pain that may delay appropriate medical therapy and even death. 4 CAN occurs in about 17% of type-1 diabetes. 5 CAN can lead to resting tachycardia, silent myocardial ischemia, and arrhythmia etc. 6 CAN may be detected by evaluating resting tachycardia, loss of sinus arrhythmia and heart rate response to Valsalva meneuver. ABSTRACT Objective: To determine the frequency of Cardiac Autonomic Neuropathy (CAN) in type-1 Diabetes mellitus patients and its association with the duration of disease and glycemic control. Study Design: Descriptive study. Place and Duration of Study: Department of Medicine, Liaquat University Hospital, Hyderabad/Jamshoro, from December, 2004 to April, 2005. Methodology: Fifty patients of type-1 Diabetes Mellitus (DM) of ≥ 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 electrocardiogram (ECG). An R-R variation with respiration of >15 beats per minute was taken normal, while 10-15 beats and <10 beats per minute were taken as borderline and definitive CAN respectively. QTc intervals were measured. Patients with HbA1c levels <7% were considered as well-controlled. The associations between CAN, the duration of diabetes and the diabetic control were determined. Results: The mean age was 35.16±10.58 years with 32 males and 18 females. The mean values for the known duration of diabetes and HbA1c were 13±7.3 years and 9.36±2.5 mg/dl respectively. Definitive and borderline CAN were noted in 20% and 24% respectively. Variability of heart rate with respiration was significantly related to the duration but not to the control of the 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 uncontrolled glycemic status. Conclusion: Cardiac autonomic neuropathy is common in long standing type-1 diabetics. CAN resulted in prolonged QTc interval that may result in cardiac arrhythmias and even death. Intensive glycemic control improves the cardiac autonomic nerve functions. Key words: Cardiac autonomic neuropathy. Resting tachycardia. Sinus arrhythmia. Valsalva maneuver. 1 Department of Medicine, Muhammad Medical College, Mirpurkhas. 2 Department of Medicine, Liaquat University Hospital, Jamshoro, Hyderabad. 3 Department of Medicine/Pharmacology 4 , Isra University, Hyderabad. Correspondence: Dr. Haji Khan Khoharo, B. No. C-17/II, Anwer Villas, Phase I, New Wahdat Colony, Qasimabad, Hyderabad. E-mail: drhajikhan786@yahoo.com Received October 26, 2007; accepted January 19, 2009. Cardiac Autonomic Neuropathy (CAN) in Type-1 Diabetes Mellitus Patients and its Association with the Duration of Disease and Glycemic Control Haji Khan Khoharo 1 , Shuaib Ansari 2 , Imran Ali Shaikh 3 and Fatima Qureshi 4 ORIGINAL ARTICLE