Management of infants with idiopathic dilatation of the right atrium and atrial tachycardia.

Idiopathic dilatation of the right atrium (IDRA) is a rare anomaly defined as isolated enlargement of the right atrium in the absence of other cardiac lesions known to cause right atrial dilatation. IDRA is a congenital anomaly with unknown pathogenesis and highly variable clinical presentation. Optimal management of severe IDRA is controversial and individualized. Literature reports of long-term follow-up have been limited. We describe a child with IDRA with rapid atrial tachycardia (AT) refractory to both medical and surgical management, and we provide long-term follow-up on our two previously reported cases, both of whom had documented AT. For infants with AT, the clinical course is unpredictable, and medical therapy is the first line of treatment. The decision to proceed with surgical resection of a giant right atrium should be made on an individual basis. Atrial resection along with a modified right atrial MAZE procedure could be considered in infants with life-threatening atrial tachyarrhythmia refractory to medical treatment. Surgical scarring of the right atrium may produce substrate for atrial arrhythmia, which may also be refractory to medical therapy. Histological examination of excised atrial tissue remains inconsistent and not contributory to the determination of the etiology of IDRA. Our three infants with IDRA illustrate unique features of their variable clinical courses, as well as continued difficulties with establishing clear guidelines with regard to surgical management of this unusual disorder.