Electrocardiogram can help diagnose cardiovascular complications in patients with hypertension. Electrocardiogram is used at Dr. Joe Nwilo Heart Centre for diagnosing atrial fibrillation, ventricular fibrillation, right bundle branch block (RBBB), left bundle branch block (LBBB), sino-atrial block and atrioventricular block. The gender, occupation, education, systolic, diastolic, pulse, body mass index (BMI), height, weight and diagnosis of patients were recorded. The data obtained were analyzed using statistical package for social sciences (SPSS, version 25.0). The results showed that BMI had a positive correlation to the diagnosis in the measurable study variables at P<0.05. In non-measurable variables, age had a positive correlation to the diagnosis at P<0.05. The most common ECG abnormality in this study was atrial fibrillation (20.75%), closely followed by ventricular fibrillation (20.25%).