ABSTRACT
Patent ductus arteriosus (PDA) is an embryologic remnant, and connects the roof of the pulmonary artery to the proximal descending aorta. In the left-sided aortic arch, the duct’s pulmonary orifice is located just leftward from the pulmonary artery bifurcation; the aortic orifice is on the medial side of the aorta, at the level or just distal to the origin of the left subclavian artery. The Electrocardiogram (ECG) is completely normal in the presence of a small duct. Moderate to severe ducts with a large left-to-right shunt present with left atrial overload and left ventricular hypertrophy; a prolonged PR interval can be seen in 10-20% of cases. P pulmonale and right ventricular hypertrophy are present in patients with Eisenmenger syndrome. Diagnostic catheterization is limited to certain patients: prior to elective closure of the PDA; or in the presence of pulmonary hypertension and increased pulmonary vascular resistance to determine their reversibility using vasodilator agents.
