MORPHOLOGIC ANALYSIS OF COMMON ATRIOVENTRICULAR VALVES IN PATIENTS WITH RIGHT ATRIAL ISOMERISM

The objective of the study was to examine the relation between the mor phology of the common atrioventricular valve and regurgitation of the valve in patients with right atrial isomerism, We examined seven conse cutive patients with documented right atrial isomerism who subsequentl y underwent postmortem examination during a 10-year period. The degree of regurgitation and the diameters of the common valve were evaluated via cineangiography, and the site of regurgitation was evaluated by e chocardiography. The morphology of the common atrioventricular valve w as assessed further at autopsy. Cineangiography revealed valve diamete rs ranging from 14.8 to 27.8 mm (mean 20.9 mm). Valvar regurgitation w as revealed within 2 months of birth in all patients. Regurgitation ab ruptly worsened in three patients after placement of a Blalock-Taussig shunt or a central shunt and postintubation. Autopsies revealed that the common atrioventricular valve consisted of four leaflets in five p atients, and three leaflets in two. The anterior leaflets were large a nd protruding in all patients, and the lateral leaflets were thickened in six, All patients had a mass consisting of the left lateral leafle ts and chordae with direct attachment of the chordae to the ventricula r muscle (the right lateral leaflet was attached to the ventricular mu scle and immobile in one patient). The lateral leaflets clung to the v entricular wall and exhibited poor movement in six patients, Leaflets with poor mobility corresponded to the regurgitant valvar site as asse ssed by echocardiography in six patients; and the regurgitation in thr ee patients with acute deterioration occurred at the valvar side with poor mobility. It is concluded that the common atrioventricular valve in patients with right atrial isomerism has morphologic characteristic s that may be associated with valvar regurgitation and malignant poten tial for abrupt deterioration after replacement of systemic-pulmonary shunting.