Prevalence and etiology of heart murmurs in first-grade students of Kerman in 1998-1999

Heart murmurs are a common finding during physical examination of children, but most of them are innocent or normal. Recognizing the etiology of heart murmurs can help us in differential diagnosis of them. The present study was undertaken to determine the prevalence and etiology of heart murmurs in 4761 school children. The sex ratio was nearly 1:1. Murmurs were heard in 459 students (9.64%) with no statistical difference between boys and girls (P>0.05). Innocent murmurs found in 298 (64.92%) and pathologic murmurs in 161 ones (35.08%). Most (91.93%) pathologic murmurs were valvular in origin and the rest (8.07%) were a sign of intracardiac shunts. Mitral valve prolapsus (MVP) was the most common valvular abnormality (77.03%). MVP was 1.71 times more prevalent in girls than in boys (P<0.05). Next common forms of valvular lesions were pulmonic stenosis (0.46%) and aortic valve stenosis (0.19%). Pulmonic stenosis was 2.67 times more prevalent in boys than in girls (P<0.05), and aortic stenosis was seen only in boys (P=0.002). Atrial septal defect (ASD) was the most prevalent form of intracardiac shunts (0.19%), and was 8 times more common in girls than in boys (P=0.018). The present study confirms previous investigations that murmurs are frequently found in school children and most of them are innocent requiring no diagnostic or therapeutic modality other than history taking and careful physical examination. On the other hand, children with pathological murmurs ought to be referred to a pediatric cardiologist for evaluation and treatment of needed.