The prevalence of unrecognized congenital heart disease among healthy elementary school students in northern Thailand

Background: Congenital heart disease (CHD) is one of the major congenital anomalies among newborns. Although many infants with CHD are symptomatic and identified soon after birth, others remain undiagnosed until the disease becomes severe. Objectives: Unravel the number of CHD cases among 7-12 years old students who reported neither clinical complication nor history about cardiac diseases, stressing the importance for regular cardiac examination in children, even if they appeared healthy. Methods: The study selected students without clinical history of heart disease from 1,041 elementary schools in northern Thailand (Tak, Nakhon Sawan and Uttaradit). Certified nurses and health officers examined the students for abnormal heart conditions. Pediatric cardiologists scrutinized the students with suspected CHD for confirmation and characterization of cardiac lesion types. Results: Out of 144,293 students included in the study, 851 students showed atypical heart symptoms, and 87 were verified to have the CHD. This conferred the prevalence rate of unrecognized CHD among the elementary school children to be 0.60 per 1,000. The frequently-detected heart defects were ventricular septal defect (41.4%) and pulmonary stenosis (16.1%). Fifty-one children (58.6%) required surgery for cardiovascular correction. The prevalence of the CHD in elementary school students ranged from 0.41 to 1.05 cases per 1000 study subjects. The greatest number of incidences was found in Tak province where medical resources are inadequate. Conclusion: This study highlights the significance of routine cardiac examination among school-aged students, particularly in the regions with limited medical facilities, providing information essential for appropriate health care planning and managements.