Type A Rastelli Atrioventricular Canal Defect (AVCD) Characteristics and Management

Anatomic Classification and Core Structural Features

The American College of Cardiology describes Type A Rastelli AVCD as a specific anatomic classification of complete atrioventricular septal defect characterized by the superior bridging leaflet of the common atrioventricular valve being divided and attached to the crest of the interventricular septum by chordae tendineae, with the left ventricular portion of this leaflet having attachments to the left side of the septum 1, 2
Type A Rastelli AVCD is the most common type, with the superior bridging leaflet divided and having chordal attachments to the crest of the interventricular septum on the left ventricular side 3
Complete AVCD with Type A anatomy includes a common atrioventricular junction, primum atrial septal defect, inlet ventricular septal defect, and five leaflets of the common AV valve: anterior bridging, posterior bridging, left mural, right anterosuperior, and right inferior leaflets 3

The American College of Cardiology recommends surgical repair typically before 6 months of age to prevent irreversible pulmonary vascular disease and Eisenmenger physiology in patients with Type A Rastelli AVCD 1, 2
The specific Rastelli type guides surgical technique for valve division and patch placement, with Type A anatomy allowing for a more straightforward two-patch repair technique 1, 2

Lifelong monitoring is essential for patients with Type A Rastelli AVCD to detect left atrioventricular valve regurgitation, left ventricular outflow tract obstruction, and conduction abnormalities including late-onset complete heart block 1, 2, 3

The European Heart Journal recommends three-dimensional echocardiography for clear visualization of all five leaflets, confirmation of the common annulus and absence of AV septum, and definitive classification of the defect as Type A by demonstrating the bridging leaflet attachments to the interventricular septum 3, 4

The American College of Cardiology notes that Type A Rastelli AVCD has strong associations with Trisomy 21 (Down syndrome) and other congenital cardiac lesions including tetralogy of Fallot, coarctation of aorta, and heterotaxy 1, 2

Complete atrioventricular canal defect (CAVC) and balanced atrioventricular septal defect (AVSD) are synonymous terms describing the same congenital heart defect, characterized by a common atrioventricular junction, an interatrial communication, an interventricular communication, and varying degrees of malformation of the left-sided component of the common atrioventricular valve, with an unrestrictive interventricular communication and bridging leaflets that usually float to varying extent within the atrioventricular septal defect, as described by the American College of Cardiology 5, 6, 7

The Rastelli classification is commonly used to describe anatomic variations of the superior bridging leaflet of the atrioventricular valve in complete AVSD, guiding the type of repair, according to the American College of Cardiology 5
If not repaired early in life, typically before 6 months of age, irreversible pulmonary vascular disease usually develops, resulting in Eisenmenger physiology, as noted by the American College of Cardiology 5
Long-term follow-up is required to monitor for left atrioventricular valve regurgitation and stenosis, left ventricular outflow tract obstruction, and arrhythmias, as recommended by the American College of Cardiology 5