Electrocardiogram characteristics and possible associated factors in healthy Japanese children: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

Abstract

Background: The number of young patients with cardiac disease has recently increased. To describe the electrocardiogram characteristics and identify the possible factors affecting the characteristics in early life might be helpful for the prevention and assessment of abnormal cardiac function. The aim of this study is to analyze the electrocardiogram characteristics of healthy children and investigate the possible associated factors in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study in Japan. Methods: Children were recruited between 2013 and 2017 and the ECG parameters for 6,061 children. Student’s t-test was conducted to confirm sex-related differences. ECG parameters were also described by age. Multiple regression analysis of 2,285 children, whose body mass index and their parents’ ECG parameters were available in addition to sex and age, was used to analyze the possible factors associated with ECG characteristics. In addition, ECG parameters were compared between gestational age < 37 (premature birth) and ≥ 37. Results: Heart rate, QRS duration, QT interval, corrected QT interval, and P-QRS-T axes showed significant sex-related differences (P < 0.05), and the QRS duration varied with age. The ECGs of parents in PR interval and QRS duration were associated with those of children (Boys: β [95% confidence interval] was 0.17[0.12–0.22] and 0.18[0.14–0.23] with mothers, 0.11[0.063–0.16] and 0.11[0.075–0.15] with fathers, Girls: 0.12[0.074–0.16] and 0.16[0.12–0.20] with mothers, 0.090[0.050–0.13] and 0.089[0.056–0.12] with fathers). Maternal QTc and P axes were also associated with child QTc and P axes. Premature birth showed significantly difference only in the QRS axis (P = 0.02). Conclusion: This study described the ECG characteristics of Japanese children and found a relation between parents and children. ECG parameters in children aged 4–9 correlate with those in their parents, but not with sex or BMI. In particular, mother’s ECG was strongly associated with that of children than father’s ECG. The relation might be reflected by both genetic background and uterine environment.