Coronary arteriovenous fistula (CAF) is a rare congenital anomaly, which can also be secondary to cardiac interventions or surgeries. We report a case of a 57-year-old female with a history of recurrent palpitations, exertional dyspnea, and worsening heart-failure symptoms. Echocardiography and coronary angiography revealed a left CAF draining into the right atrium. The patient underwent successful transcatheter closure of the CAF using a patent ductus arteriosus occluder. The patient had an uncomplicated recovery, and a 6-month follow-up showed significant improvement in her symptoms with only a small residual shunt detected on echocardiography.