Patent Ductus Arteriosus (PDA) is a heart condition that occurs when a blood vessel called the ductus arteriosus fails to close after birth. This vessel connects the pulmonary artery to the aorta in a fetus, allowing blood to bypass the lungs. Normally, it closes shortly after birth, but in PDA, it remains open, leading to abnormal blood flow between the two arteries. When PDA persists, it can cause increased blood flow to the lungs and strain on the heart. Symptoms may include rapid breathing, fatigue, and poor weight gain in infants. Treatment options include medication or surgery to close the ductus arteriosus and restore normal blood circulation.