The most common cause by far of pulmonic regurgitation is Secondary pulmonary hypertension Less common causes are Congenital heart disease Idiopathic pulmonary artery dilation Infective endocarditis Surgical repair of tetralogy of Fallot Rare causes are Carcinoid syndrome Rheumatic fever Following intervention for valvular pulmonic stenosis (early or late) Severe pulmonic regurgitation is rare and most often results from an isolated congenital defect involving dilation of the pulmonary artery and pulmonary valve annulus.