LEFT-SIDED OBSTRUCTIVE LESIONS IN ATRIOVENTRICULAR SEPTAL-DEFECTS - AN ANATOMIC STUDY

  • 1 January 1982
    • journal article
    • research article
    • Vol. 83  (3) , 453-460
Abstract
Actual and potential factors that create an obstruction to the flow within the systemic side of the heart were analyzed in 114 specimens with atrioventricular septal defects. Hearts with separate right and left atrioventricular orifices and with common atrioventricular orifice were included. Potential inlet obstruction was due to tethering of the cleft of the left atrioventricular valve to the septum in 17.5%, incomplete cleft in 8% and deformed valve leaflets in 70% of cases. Potential factors predisposing to left ventricular outflow tract obstruction were seen in 70% of cases, 21% being due to abnormal position of the papillary muscle and the remainder due to intrinsic hypoplasia of the outflow tract. Anatomic factors producing unequivocal obstruction were seen in 29% of cases. Twenty-two percent had obstructions at the inlet level, of which 13% were due to malformations of the left atrioventricular valve or the left component of a common valve. The other 9% had overall inlet obstruction due to severe hypoplasia of the left ventricle itself. Unequivocal outlet obstruction was observed in 7% of cases, 5% due to abnormal disposition of papillary muscles in the outflow tract and 2% to aneurysm of the interventricular septal remnant. Although anatomic obstruction occurs in the minority of cases (29%), potential obstruction must be taken into account when considering surgical repairs.