Evaluation of mean “R” wave amplitude in lead V1 of electrocardiogram among term newborn infants in tertiary care institution in South India

Background: The changes in the left ventricle to right ventricle muscle mass ratio account for the majority of the age-related changes in pediatric electrocardiograms (ECGs). A newborn's right ventricle muscle mass is more than the newborn's left ventricle. Physiologically, newborn infants have a dominant right ventricle. Race differences in QRS voltage normal values exist. Compared to Euro-Americans, African-Americans have a higher upper normal limit of QRS voltages. Typically, right ventricular hypertrophy is seen in newborns. To distinguish between pathological and physiological newborn hypertrophy, it is critical to measure the mean QRS amplitude in healthy newborns. This is the first study on the Indian population, with previous ones being conducted among African-Americans. Methodology: Between 2015 and 2016, this prospective observational study was carried out in the pediatrics department of a tertiary care facility in India. The study included 76 term newborns who were under 3 days old. In Chennai's Kilpauk Medical College and Hospital, the newborn infants underwent clinical examinations as well as echocardiography before receiving their ECGs. A baseline questionnaire that had been previously created was used for data collection. Results: For the Indian population, the mean R wave amplitude was 11.56 mm, with a standard deviation of 2.96 mm, and the 5th and 95th percentiles were 6.85 mm and 16.15 mm, respectively. The Fridericia formula for the mean QTc interval gives a value of 357.14 ms, a standard deviation of 34.072 ms, and a 95% confidence interval of 349.36–364.93 ms. Since a newborn's heart rate typically exceeds 100 beats/min, the measurement of QTc using the Fridericia formula more accurately predicts QTc in the newborn. The mean heart rate was 125.75 beats/min, with a standard deviation of 15.44 beats/min, and the 5th and 95th percentiles were 93.7 and 149 beats/min, respectively. Conclusions: The “R” wave mean amplitude in lead V1 was 11.56 mm, with a 2.96 mm standard deviation; the fifth and ninety-fifth percentiles, respectively, were 6.85 mm and 16.15 mm. The population's “R” wave in the lead V1 exhibits racial differences in amplitude.