Congenitally corrected transposition with atrioventricular septal defect

Abstract

We describe 4 cases of congenitally corrected transposition associated with atrioventricular septal defect, diagnosed by echocardiography and angiocardiography. Two had usual atrial arrangement and two had mirror imaged atrial arrangement . All cases were associated with subpulmonary valvar stenosis. All patients presented with cyanosis and were in sinus rhythm. Atrioventricular septal defect with common atrioventricular junction was easily diagnosed on the basis of a common atrioventricular valve permitting interatrial and interventricular communications. All patients had balanced right and left ventricles. The echocardiographic recognition of the ventricles was based on the presence of the moderator band within the morphologically right ventricle, the characteristics of the apical septal trabeculations, and the shape of the ventricles. Angiocardiographic recognition of the ventricles was achieved on the basis of right and left ventriculography. In one case with usual atrial arrangement, we recorded two His bundle potentials, one anteriorly and another posteriorly. Atrial stimulation revealed blocked atrioventricular conduction at the level of the posterior bundle, and normal atrioventricular conduction through the anterior bundle. In both cases with atrial mirror-imagery, only a posterior His bundle potential was found, with normal atrioventricular conduction revealed by atrial stimulation The clinical course with this combination depends on the other lesions present in addition to the common atrioventricular valve. Our electrophysiological studies show that the conduction system in presence of a common atrioventricular valve is as expected for congenitally corrected transposition with two atrioventricular valves.

Twin Atrioventricular Nodes Connecting to Sling of Conduction Tissue in Congenitally Corrected Transposition Associated With Straddling Tricuspid Valve

“…6 In these settings, the atrial and ventricular structures are better aligned, thus permitting normal formation of the posterior node. [3][4][5][6][7] In addition, the combination of L-loop ventricle and complete AV septal defect was believed to be the morphologic substrate for twin AV nodes and/or sling of conduction tissue connecting the AV nodes. [5][6][7] However, straddling and overriding of the tricuspid valve literally or by definition indicate malalignment of the inlet part of the ventricular septum and atrial septum by an abnormally large ventriculoatrial septal angle.…”

“…[3][4][5][6][7] In addition, the combination of L-loop ventricle and complete AV septal defect was believed to be the morphologic substrate for twin AV nodes and/or sling of conduction tissue connecting the AV nodes. [5][6][7] However, straddling and overriding of the tricuspid valve literally or by definition indicate malalignment of the inlet part of the ventricular septum and atrial septum by an abnormally large ventriculoatrial septal angle. 8 Therefore, anterior AV conduction tissues are expected in this setting on the aforementioned theoretical basis; however, the present report describes an exception to the rule that combination of straddling tricuspid valve is unlikely to be associated with twin AV nodes/sling.…”

“…1 Several factors have been reported to mitigate the effects of the malalignment, including straddling mitral valve, 2,3 situs inversus, 4 the presence of a stenotic or atretic pulmonary trunk or outflow, 5 and the absence of contiguity of septal structures as occurs in combination with AV septal defect. 6 In these settings, the atrial and ventricular structures are better aligned, thus permitting normal formation of the posterior node. 3 –7 In addition, the combination of L-loop ventricle and complete AV septal defect was believed to be the morphologic substrate for twin AV nodes and/or sling of conduction tissue connecting the AV nodes.…”

“…3 –7 In addition, the combination of L-loop ventricle and complete AV septal defect was believed to be the morphologic substrate for twin AV nodes and/or sling of conduction tissue connecting the AV nodes. 5 –7…”