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. If it remains open, it can lead to increased blood flow to the lungs and heart, causing potential complications. Symptoms of PDA may include rapid breathing, fatigue, and poor weight gain in infants. Diagnosis is typically made through a physical examination and imaging tests like echocardiography. Treatment options may involve medication or surgery to close the ductus arteriosus and prevent further health issues.