Anomalous aortic origin of a coronary artery (AAOCA)

In younger patients (age <35), sudden cardiac death (SCD) is usually due to underlying structural heart disease, with ventricular tachyarrhythmia as the most common terminal event. The high-risk types of AAOCA are among the most common causes of SCD in young athletes; in one study, autopsies on military recruits with SCD revealed AAOCA to be the cause in about one-third of cases.

Two types of AAOCA commonly associated with SCD are the left main coronary artery originating from the right aortic sinus and the right coronary artery originating from the left aortic sinus. These defects create the sharp curvature of the anomalous coronary artery, making it less amenable to high-volume flow. In addition, the anomalous artery passes between the aorta and the pulmonary artery, making it susceptible to external compression during exercise.Patients with AAOCA may experience exertional angina, lightheadedness, or syncope; however, some patients experience SCD without any premonitory symptoms. Resting ECG is typically unremarkable. A transthoracic echocardiogram can sometimes make the diagnosis, but it can also miss or inaccurately characterize AAOCA. CT coronary angiography or coronary magnetic resonance angiography provides the best visualization of coronary anatomy, and are the diagnostic tests of choice in patients with suspected AAOCA.