BACKGROUND Congestive heart failure (CHF) is a common Emergency Department (ED) disorder that accounts for >5 million ED visits annually. Although quite rare, patent ductus arteriosus (PDA) is a serious cause of CHF that if left untreated can lead to life-threatening sequelae, such as hypertensive pulmonary vascular disease, endarteritis, and aneurysms of the ductus. OBJECTIVE To discuss a case of PDA leading to CHF that illustrates one of the common complications of untreated PDA. CASE REPORT A 35-year-old woman presented to the ED with a 2-month history of shortness of breath, dyspnea on exertion, decreased exercise tolerance, and orthopnea. The physical examination revealed a 4/6 continuous machine-like murmur. In the presence of new CHF and an atypical murmur, a transthoracic echocardiogram was performed that confirmed the diagnosis of PDA. She underwent an uncomplicated percutaneous closure of the ductus with significant improvement in her symptoms. CONCLUSIONS Persistent PDA in adulthood is a rare but important cause of CHF with significant morbidity and mortality if not appropriately diagnosed and treated.