Management of Infants with Idiopathic Dilatation of the Right Atrium and Atrial Tachycardia

Abstract

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.

Congenital Idiopathic Dilatation of the Right Atrium: Antenatal Appearance, Postnatal Management, Long-Term Follow-Up and Possible Pathomechanism

“…Congenital IDRA is a rare condition, reported in fetuses [11,12], children [1,13], infants [1] and in adults [14]. There are only 31 reports in the literature about IDRA or congenital RA aneurysm.…”

“…Therefore, because of inconsistent terminology, the first description of IDRA was cited differently by Borrichin in 1676 [8], Semans and Taussig in 1938 (cited by Imren et al, 2006 [4]) and Morrow and Behrendt [9] in 1968. Bailey (cited by Forbes et al, 2007 [1]) was the first to excise a diverticulum of the RA.…”

“…There is no consensus on whether it is congenital or acquired [3]. Some prefer to call it idiopathic dilatation of the RA [1], while others label it as congenital enlargement of the RA [4] or congenital right atrial diverticulum [5]. There are clear characteristics distinguishing an aneurysm, ‘as a dilatation of the atrium involving all layers of the atrial wall, from a diverticulum, an entry of fibromuscular strands across the atrial wall’ [6].…”

“…It is defined as isolated enlargement of the right atrium (RA) in the absence of other cardiac lesions known to cause right atrial dilatation [1,2]. There is no consensus on whether it is congenital or acquired [3].…”

Spontaneously regressed congenital idiopathic dilatation of the right atrium in the newborn

“…Accurate diagnosis is necessary for proper medical and surgical management. Although long-term follow-up literature reports have been limited, the number of authors supporting RA surgical treatment is more than the ones supporting medical follow-up (2)(3)(4)(5). Up to date, only few cases have been diagnosed.…”