▁This ▁revers al ▁of ▁the ▁pressure ▁gradient ▁across ▁the ▁AS D ▁causes ▁the ▁sh unt ▁to ▁reverse ▁- ▁a ▁right - to - left ▁sh unt . ▁ ▁This ▁phenomen on ▁is ▁known ▁as ▁Eisen men ger ' s ▁synd rome . ▁ ▁Once ▁right - to - left ▁sh un ting ▁occurs , ▁a ▁portion ▁of ▁the ▁o xygen - po or ▁blood ▁gets ▁sh unted ▁to ▁the ▁left ▁side ▁of ▁the ▁heart ▁and ▁e ject ed ▁to ▁the ▁peri pher al ▁v asc ular ▁system . ▁ ▁This ▁causes ▁signs ▁of ▁cy anos is . ▁ ▁Di agn osis ▁ ▁Most ▁individuals ▁with ▁a ▁significant ▁AS D ▁are ▁diagn osed ▁in ▁u tero ▁or ▁in ▁early ▁child hood ▁with ▁the ▁use ▁of ▁ul tr ason ography ▁or ▁aus c ult ation ▁of ▁the ▁heart ▁sounds ▁during ▁physical ▁exam ination . ▁ ▁Some ▁individuals ▁with ▁an ▁AS D ▁ ▁have ▁surg ical ▁correction ▁of ▁their ▁AS D ▁during ▁child hood . ▁ ▁The ▁development ▁of ▁signs ▁and ▁sympt oms ▁due ▁to ▁an ▁AS D ▁are ▁related ▁to ▁the ▁size ▁of ▁the ▁int rac ard iac ▁sh unt . ▁Ind ividual s ▁with ▁a ▁larger ▁sh unt ▁tend ▁to ▁present ▁with ▁sympt oms ▁at ▁a ▁younger ▁age . ▁ ▁Ad ult s ▁with ▁an ▁un correct ed ▁AS D ▁present ▁with ▁sympt oms ▁of ▁d ys p nea ▁on ▁ex ert ion ▁( short ness ▁of ▁breath ▁with ▁minimal ▁exercise ), ▁con gest ive ▁heart ▁failure , ▁or ▁c ere bro vas cular