QT Dispersion Pattern in Non-Hospitalized Uncomplicated Clinical Hypothyroidism

The present study was aimed to evaluate the dispersion of QT interval, which is an index of inhomogeneity of ventricular repolarization and heart rate, and a measure of cardiac autonomic modulation in patients with clinical hypothyroidism .A total of 60 comprising of 30 healthy subjects who underwent TSH estimation for any other reasons and found to be normal were taken as control group and 30 patients who are diagnosed with clinical hypothyroidism, were selected from outpatient clinic of Department of General Medicine were taken as cases.. The ECG was recorded with BPL Cardiart 6108 T ECG Machine (BPL Manufacturing Company, BPL limited, India) and heart rate and QT dispersion was calculated. The mean QT intervals in all the leads of ECG differed significantly (p<0.05) between hypothyroid cases and normal control cases except in lead I . Mean QTc from the cases differed significantly (p<0.5) from the control group . Both QTmin and QTmax of cases and controls showed statistical significant difference (p=0.22 and P=0.014 respectively). Hypothyroid patients showed a highly significant increase(p<0.0001) in mean QTdis in respect to control group. In conclusion, the present study confirms the role of thyroid hormones on the cardiovascular functionality, especially on the ventricular repolarization and autonomic modulation of cardiac activity.