Congenital coronary anomalies are quite common and frequently have no clinical consequence. On occasion, a “malignant” anomaly can occur resulting in myocardial ischemia, angina and even sudden cardiac death. These anomalies pass between the aorta and the pulmonary artery (known as an interarterial course) which can cause compression.
Coronary anomalies are the second leading cause of sudden cardiac death in young athletes (leading cause is hypertrophic obstructive cardiomyopathy or HOCM). Some examples include the left anterior descending originating from the right coronary cusp, the right coronary artery arising from the left main coronary artery, and the circumflex coronary artery arising from the right coronary cusp.