Electrocardiographic abnormalities in persons with type 2 diabetes in Kaduna, Northern Nigeria

Background and Objective: Diabetes mellitus is the most common endocrine disorder in Nigeria. Type 2 Diabetes Mellitus (T2DM) is associated with increased cardiovascular risk, in part due to accelerated subclinical atherosclerosis. Ischaemic Heart Disease (IHD) is an important chronic complication of diabetes mellitus because it is the most prevalent amongst cardiovascular diseases and a major cause of morbidity and mortality. This study sets out to determine the most frequent electrocardiographic (ECG) abnormalities in persons with T2DM in Kaduna (a sub-urban environment). Subjects, Materials and Methods: 150 consecutive persons with T2DM and 150 normal controls were recruited from the Diabetes Clinic of Ahmadu Bello Teaching Hospital, Kaduna for the study. Relevant history and physical examination findings were recorded in a protocol. The variables studied were: gender, age, smoking habit, physical activity, and waist circumference, body mass index (BMI) and blood pressure. Resting ECG was recorded and abnormalities grouped according to the classification: ST-T segment changes, left ventricular hypertrophy (LVH) and conduction defects. Serum lipids were also compared. Results: The mean age of the diabetics and controls were not significantly different (50.5 ± 9.9yrs vs. 51.1 ± 10.3yrs), respectively. Fifty percent were females. BMI and waist circumference were significantly (p<0.05) higher in diabetics (BMI 27.89 ± 1.78 kg/M2, WC 96 ± 10.2 cm) compared to control (BMI 24.22 ± 1.51 Kg/M2, WC 86 ± 6.5cm). Sixty two percent of diabetics were hypertensive and 20% of diabetics and 1.5% of control subjects had ECG evidence of IHD, and 7% of diabetics had LVH. Seventy one percent of persons with T2DM had dyslipidaemia, a significant (p<0.05) increase compared to control. Conclusion: The various resting 12-lead ECG findings among persons with T2DM in this study reflect non-specific features of cardiovascular diseases in general. The most frequent ECG abnormalities T2DM are ST-T segment depression, and left ventricular hypertrophy. Ischaemic heart disease is emerging fast, in a developing, poverty-stricken environment like Nigeria and should be routinely examined. Hypercholesterolaemia and female gender are the strongest and most frequent factors associated with IHD.