Atrioventricular septal defect with double-outlet right atrium

Ventriculoatrial malalignment in atrioventricular septal defect resulting in uniatrial biventricular connection: surgical options

Background

Uniatrial biventricular connection (UBC) is a rare cardiovascular anomaly characterized by absence of one atrioventricular connection and drainage of the other atrium via a solitary atrioventricular valve into both ventricles. The absent atrioventricular connection may affect either the left or right atrium. Because of the absence of one atrioventricular connection hearts with UBC have been classified among functionally univentricular hearts requiring palliative treatment according to the Fontan principle.

Aims/objective

We report two further patients with UBC. In one of these patients careful echocardiographic examination of the atrioventricular junction in early infancy revealed the possibility of biventricular repair based on the favorable anatomy of the atrioventricular valve and balanced ventricles in the presence of an inlet ventricular septal defect (VSD).

Case presentations

Both patients presented in the neonatal period for evaluation of complex congenital heart disease. The anatomy of the atrioventricular valves in our patients was indistinguishable from atrioventricular septal defects exhibiting the morphology of a common valve with superior and inferior bridging leaflets. The common atrioventricular valve was connected exclusively to the right atrium draining into both ventricles while the left atrium drained into the right atrium via a secundum atrial septal defect. In one of our patients biventricular repair with good longterm-result was performed by reseptation of the atria, patch repair of the VSD and septation of the atrioventricular valve. The second patient underwent univentricular palliation according to the Fontan principle.

Discussion/conclusion

The echocardiographic findings in our patients suggest that at least some patients with UBC represent a variant of atrioventricular septal defects associated with extreme ventriculoatrial malalignment resulting in fusion of the deviated primary atrial septum with the lateral aspect of the atrioventricular junction. This offers the option of septation of the common atrioventricular valve and biventricular repair in patients with adequate size of both ventricles. Exact echocardiographic analysis of the morphology of the atrioventricular valve is essential to distinguish these patients with a morphologically common atrioventricular valve in early infancy from other variants of absent atrioventricular connection and to select those who are suitable for biventricular repair.

Double-Outlet Right Atrium: Review of a Rare Anomaly With an Exemplary Case

BACKGROUND

Double-outlet right atrium (DORA) is a rare congenital cardiac defect, where the right atrium (RA) is connected to both the right ventricle (RV) and the left ventricle (LV). Double-outlet right atrium is classified into two types, each containing two subtypes: malaligned atrial septum with common or single atrioventricular (AV) valve and malaligned ventricular septum (VS) with adequate or inadequate RV. The VS type is characterized by straddling right AV valve (RAVV) with intact VS, resulting in two RAVV orifices.

METHODS

We report a case of "acquired DORA" in a 17-year-old male patient previously treated with subaortic VSD closure. At admission, we diagnosed DORA with VS malalignment and adequate RV. The patient had 2 orifices within the RAVV, connecting the RA to both the RV (via RAVV orifice 1) and the LV (via RAVV orifice 2). The latter was insufficient, with severe LV to RA shunt. A review of the literature indexed in PubMed and Scopus databases was undertaken.

RESULTS

The patient underwent biventricular repair through closure of the RAVV orifice 2 with a pericardial patch. Pacemaker implantation for complete AV block was necessary. Postoperative course and follow-up were regular. The literature review showed 39 cases of DORA, of which 8 had a malaligned VS and an adequate RV, as in our case.

CONCLUSION

Acquired DORA is an interesting post-surgical variant of a rare congenital heart defect. Biventricular repair is a feasible and viable option, which involves closing the third AV orifice. Careful attention is required in order to avoid injury to the conduction system.

Left atrial outflow obstruction in double-outlet right atrium

We describe an unusual case of partial atrioventricular septal defect with malalignment of the septum primum to the left atrium with respect to the ventricular septum, committing the tricuspid valve to both ventricles (double-outlet right atrium). Abnormal attachment of the septum primum to the lateral aspect of mitral annulus resulted in left atrial outflow obstruction. The patient underwent successful surgical correction.

Clarifying the atrioventricular junctional anatomy in the setting of double outlet right atrium

Double outlet atrium is a rare cardiac anomaly wherein one of the atriums, most frequently the right atrium, opens into both the ventricles. Although seen more commonly in the setting of atrioventricular septal defect, this arrangement can also be found when one of the atrioventricular connections is atretic due to absence of the atrioventricular connection and the other atrioventricular valve straddles the muscular ventricular septum. It is the specific anatomy and connections of the atrioventricular junction that clarifies the situation and distinguishes between these two types of double outlet atrium. In this report, we present a case of double outlet right atrium co-existing with the absence of left atrioventricular connection. We then discuss the morphologic aspects of this interesting anomaly.

Deviation of atrial septum primum in association with normal left atrioventricular valve size

Deviation of atrial septum primum (DASP) is an unusual anatomic finding in patients with normal left atrioventricular valve size. To better describe this anomaly, we reviewed our echocardiographic database from January 1987 to May 1999. Twenty-four patients had DASP and a normal-sized left atrioventricular valve. Six had inferior DASP with common atrioventricular canal. Of these, 3 had evidence of left atrial outlet obstruction. Five survived surgical intervention with follow-up of 24 +/- 14 months. Seventeen patients had superoposterior deviation with the right pulmonary veins draining anomalously to the right atrium. Only 8 of 17 underwent surgical resection; none of the 17 have evidence for late development of obstruction. One patient had both inferior deviation and superoposterior DASP and underwent early successful repair. DASP occurs in patients with normal left atrioventricular valve size. Inferior DASP can result in left atrial outlet obstruction and requires surgical intervention. Superoposterior DASP carries less physiologic consequence. Echocardiography can distinguish this anomaly from other forms of left atrial obstruction.

Special problems in Fontan-type operations for complex cardiac lesions

Four patients with complex cardiac lesions, who underwent successfully a Fontan type of operation are presented, each case representing a particular problem in surgical management. The first exhibited displacement of a trileaflet straddling and overriding left atrioventricular valve in addition to tricuspid atresia, while the second one had unilateral lung perfusion. In the third case, a stenosis had developed near the origin of the right pulmonary artery, and pulmonary vascular resistance could not be determined prior to the definite palliation procedure, whereas the fourth patient presented with stenosis of the left atrioventricular valve. Surgery was planned after detailed evaluation of the morphologic and hemodynamic features by means of echocardiography and cardiac catheterization. Our results illustrate the common tendency to extend the limits for modified Fontan procedures, which also includes revision of the original criteria for selection.