International Journal of Physiology

There are various physiological factors that affect ECG waveforms which include sex, age, ethnicity, height, weight, torso morphology, body mass index, and pregnancy. Such characteristics account for the differences among individuals and produce interindividual variability in ECGs. Physiological and anatomical alterations develop in many organ systems during the course of pregnancy and delivery. The pregnancy-induced changes in the cardiovascular system develop primarily to meet the increased metabolic demands of the mother and fetus. The present study was done to find out the electrocardiographic changes in relation to pregnancy.

To study variations in ECG waveforms in 3^rd trimester of normal pregnancy.

This case-control study consisting of 30 normal non pregnant women and 30 normal healthy pregnant women, each between ages 18–30 years were selected from student population and from obstetric outpatient department, VIMS, Bellary respectively. The ECG was recorded and was evaluated for different parameters like heart rate, P wave, PR interval, QRS complex, QRS axis, QT interval and QT_c interval and results were drawn.

There was statistically significant increase in heart rate, QT interval, QT_c interval in 3^rd trimester pregnant women when compared to controls and also statistically significant decrease in PR interval and QRS axis in 3^rd trimester pregnant women when compared to controls.

The study shows that there are a variety of adaptations of cardiovascular system during normal pregnancy which bring about changes in ECG in the absence of any cardiac disease. Knowledge of these changes is essential in the management of women with cardiovascular disease.