Spontaneous-onset atrial fibrillation in a toddler with review of mechanisms and etiologies.

Atrial fibrillation is a relatively rare form of arrhythmia in the pediatric population. When it is seen in an infant or child, it is often associated with a structural heart abnormality, particularly after surgical repair or palliation of congenital heart disease. Other episodes may be associated with metabolic derangements. This report discusses the unique case of a toddler with new-onset atrial fibrillation that was devoid of a readily identifiable etiology. It also reviews the literature and the implications of such a case for the primary care practitioner.