Sinus node dysfunction in a healthy pediatric population.

ECG recordings of 624 healthy children (age range 6 to 12 years) from a rural population were analyzed for evidence of sinus node dysfunction. Twelve children were found to have the disorder and they underwent further assessment in order to establish any etiological factors or anatomical abnormalities. All the children were asymptomatic and physical examination was completely normal. Standard ECG taken during 24-h monitoring demonstrated that the most common finding, seen in 10 of 12 patients, was that of sinus arrest. Second-degree sinoatrial exit block, Mobitz type I, occurred in four children and Mobitz type II was seen in three. Two of the children were found to have holosystolic mitral valve prolapse, which was in the normal frequency range for a population of healthy children. After a 2-year follow-up and reassessment, there was no change in the symptomatology, the ECG tracings or the physical findings of any of the children.