Prevalence and clinical significance of cardiac murmurs in schoolchildren.

Objective: To determine the prevalence and clinical significance of heart murmurs detected during heart disease screening among apparently healthy schoolchildren.

Design: Cross-sectional study.

Setting: 32 elementary schools in Dongguan City of China.

Patients: 81,213 schoolchildren aged 5-13 years from different elementary schools.

Main Outcome Measures: The prevalence and clinical significance of heart murmurs among schoolchildren.

Results: Murmurs were detected in 2193 schoolchildren (2.7%), of whom 215 had a structural heart disease (SHD). Of patients who had SHD, 198 children had congenital heart disease (CHD), 12 had mitral valve prolapse and 5 had rheumatic heart disease. In patients who had CHD, the most common diagnosis was a ventricular septal defect. With respect to sex, SHDs were equally distributed between males and females. Of the schoolchildren who had a murmur, 1797 (81.9%) had a murmur with the loudness of grade 1 or 2 and 396 (18.1%) had a murmur with the loudness of grades 3-6. The prevalence of SHD fell significantly with increasing age.

Conclusions: The study suggested that apparently healthy schoolchildren with grade ≤2 cardiac murmurs are least likely to have underlying SHD, especially in those aged ≥10 years. However, echocardiography should be performed in younger schoolchildren with cardiac murmur grade ≥3.