Three-Dimensional In-vivo Dimensions of ‘He’s Triangle’ during Acute Left Ventricular Ischemia
David T. Lai FRACS, Frederick A. Tibayan MD, Tomasz A. Timek MD, David Liang MD, George T. Daughters MS, Neil B. Ingels, Jr. PhD, D. Craig Miller MD

Changes in the dimensions of ‘He’s triangle’ (formed by mitral leaflet segments subtending two associated chordae tendineae) derived from data obtained in in-vitro mitral valve models have been proposed to provide a mechanistic explanation for mitral leaflet malcoaptation. The in-vivo dynamics of He’s triangle, however, have not been hitherto determined. With acute posterolateral ischemia, the in-vivo lengths of first-order and second-order chordae tendineae remained relatively constant, but the anterior and posterior mitral leaflet lengths were not constant as the leaflets ‘unfurled’ during acute left ventricular ischemia. These geometric changes may provide further insight into the mechanisms of acute ischemic mitral regurgitation, though it is not clear how they will be clinically helpful.