ral ▁val ve ▁allows ▁blood ▁to ▁flow ▁from ▁the ▁left ▁at rium ▁into ▁the ▁heart ' s ▁main ▁p ump ing ▁chamber ▁called ▁the ▁left ▁vent ric le . ▁It ▁then ▁clos es ▁to ▁keep ▁blood ▁from ▁le aking ▁back ▁into ▁the ▁left ▁at rium ▁or ▁l ungs ▁when ▁the ▁vent ric le ▁contract s ▁( s que ez es ) ▁to ▁push ▁blood ▁out ▁to ▁the ▁body . ▁It ▁has ▁two ▁f laps , ▁or ▁leaf lets , ▁known ▁as ▁c us ps . ▁ ▁The ▁techniques ▁of ▁mit ral ▁val ve ▁repair ▁include ▁inserting ▁a ▁cloth - cover ed ▁ring ▁around ▁the ▁val ve ▁to ▁bring ▁the ▁leaf lets ▁into ▁contact ▁with ▁each ▁other ▁( ann ul op last y ), ▁removal ▁of ▁redundant / lo ose ▁segments ▁of ▁the ▁leaf lets ▁( quad r angular ▁res ection ), ▁and ▁re - s us p ension ▁of ▁the ▁leaf lets ▁with ▁artificial ▁( G ore - Tex ) ▁c ords . ▁ ▁Pro ced ures ▁on ▁the ▁mit ral ▁val ve ▁usually ▁require ▁a ▁median ▁stern ot omy , ▁but ▁adv ances ▁in ▁non - in vas ive ▁methods ▁( such ▁as ▁key hole ▁surg ery ) ▁allow ▁surg ery ▁without ▁a ▁stern ot omy ▁( and ▁resulting ▁pain ▁and ▁scar ). ▁ ▁Min im ally ▁invas ive ▁mit ral ▁val ve ▁surg ery ▁is ▁much ▁more ▁techn ically ▁demand ing ▁and ▁may ▁involve ▁higher ▁risk . ▁ ▁Occ asion ally , ▁the ▁mit ral ▁val ve ▁is ▁ab normal ▁from