We describe a patient in whom this anomaly was diagnosed during cardiac catheterization for evaluation of progressive shortness of breath and mild to moderate mitral regurgitation founded on a transthoracic echocardiogram.A 58-year-old hypertensive female was evaluated for progressive shortness of breath. Her physical examination showed a regular heart rate and rhythm, with normal heart sounds with a holosystolic systolic murmur on the 4th intercostal midclavicular line on auscultation. Electrocardiography showed normal sinus rhythm and criteria and possible left ventricular hypertrophy. Stress Echocardiogram showed with no evidence of ischemia preserved left ventricular function with an ejection fraction of 55-60%, with mild to moderate mitral regurgitation. Patient underwent a coronary catheterization for persistent shortness of breath which indicated no evidence of obstructive coronary disease, normal left ventricular function with mild to moderate mitral insufficiency. Angiography of the right coronary artery showed a very large and tortuous artery that collateralizes into the left main system and supplies the entire left coronary artery system. The left main coronary origin was from the pulmonary artery. CTA confirmed the same findings. The recommendations between cardiology and cardiothoracic surgery were to maximize medical therapy and follow up due to lack of myocardial ischemia or severe valvular disease. Currently there are no guidelines or gold standard management for patients with adult form of ALCAPA that present without ischemic burden or for patients with the disease that present asymptomatic with significant coronary collateralization.