<prompt> Large PDA leads to -Endocardial valvulitisEisenmenger syndromeCHFAll of above  <response>: Ans. is d i.e., AH of above Patent ductus arteriosus PDAo Small PDA may not cause any complication but targe defect if untread may leads to :Pulmonary hypertension Left to Right shunt leads to too much circulation of blood in lung which leads to pulmonary hypertension.Eisenmengers syndrome - Large standing pulmonary hypertension leads to permanent lung damage and causes Right to Left shunt.Endocarditis.Arrhythmia Enlargement of heart due to PDA increase risk of arrhythmias. 