[Echocardiographic signs and differential diagnosis of the infravalvular form of an oblique atrioventricular canal].

Differential diagnosis of tricuspid valve abnormality in patients with infravalvular oblique atrioventricular canal is outlined. Apart from direct echocardiographic evidence of interventricular septal defect (disorder of septo-aortal contact localization of both atrioventricular valves through the defect, without the separating interventricular septum), these patients showed signs of tricuspid valve dysfunction, such as increased amplitude and rate of anterior tricuspid cusp opening, pathologic anteriosystolic movement of the cusp, excessive and fragmentary movement of the septal cusp and, in isolated cases, flat-wave cusp fibrillation during ventricular systole, with increased ultimate diastolic diameter of the right ventricle and its outgoing tract.