Sudden death in a young athlete due to an anomalous commissural origin of the left coronary artery, and focal intimal proliferation of aortic valve leaflet at the adjacent commissure.

Sudden death occurred in a 15-year-old female athlete with an unusual anomalous left coronary artery. The left coronary artery origin was at (below) the commissure between the left and noncoronary aortic valve cusps. The ostium was slitlike and had an aortic ridge superiorly. In addition, there was an anomalous moundlike intimal proliferation of the noncoronary leaflet adjacent to the left coronary ostium that may have been an additional factor contributing to obstruction of coronary blood flow during diastole.