Evaluation of corrected QT interval in hypertensive and normotensive subjects of Andhra Pradesh, India

Abstract

Background: Hypertension being a significant cause of morbidity and mortality worldwide demands research. Left ventricular hypertrophy which is one of its complications may lead to fatal arrhythmias and sudden death. Corrected QT interval (QTc) obtained from electrocardiogram (ECG) may be used to screen high-risk hypertensive patients. Aims and Objectives: The aims of the study were to evaluate the QTc interval of hypertensive cases and normotensive controls, also to study the gender differences in QTc interval among hypertensive and normotensive groups, and further to explore the correlation of QTc interval with with systolic BP (SBP) and diastolic BP (DBP). Materials and Methods: A total of 50 hypertensive cases and 50 normotensive controls in the age group 35–45 years were the subjects. Blood pressure (BP) was recorded thrice with 2 min interval, and the average was considered for analysis. A standard 12-lead ECG was recorded, and QT and RR interval was measured. QTc interval in seconds was calculated using Bazett’s formula. Unpaired-Samples t-test and Pearson’s correlation were used to analyze the data. Results: QTc interval was significantly longer in the hypertensive group when compared to normotensives. It was also significantly longer in hypertensive females when compared with hypertensive males. However, there was no significant difference among normotensive males and females. Further, QTc interval was positively and significantly correlated with both SBP and DBP. Conclusion: QTc interval being a cheaper, non-invasive ECG parameter may be used in detecting ventricular repolarization defects in hypertension and should not be neglected especially in developing countries like India. This would help in risk stratification and prognosis of hypertensive patients and prevention of fatal arrhythmias and sudden cardiac death.