Figure 1.

Mitral valve prolapse–related echocardiographic measurements and strain parameters. Superior leaflet displacement is measured as the distance from the most superior point of a prolapsing leaflet to the mitral annular line in systole (left upper, bidirectional arrow). Papillary muscle (PM) displacement is measured as the difference between distance from PM tip to mitral annular line in early systole and late systole (right upper, bidirectional arrows). Mitral annular disjunction is evaluated as separation between the mitral posterior leaflet-left atrial wall junction and the end of the posterior myocardium (left lower, bidirectional arrow). Systolic curling (right lower) is characterized by exaggerated apical systolic motion of the posterior mitral annulus (① single red arrow) and inward excursion of the adjacent posterobasal myocardium (② triple red arrows) associated with papillary muscle traction (③ orange single arrow) tugged by superior leaflet displacement (④triple orange arrows). Orange dotted circle shows how these structures appear to move as a mechanically-linked (curling) loop in systole. Postsystolic shortening (PSS: orange arrow) is shown after aortic valve closure (end-systole) in upper panel. PSS is calculated as %([PSS–end-systolic strain]/PSS). Middle, Time to peak in each regional strain (white arrows). Mechanical dispersion is defined as standard deviation of time to peak in 18 segments. Lower, Double-peak strain pattern as distinct pre–end-systolic and post–end-systolic strain peaks (orange arrows). AVC indicates aortic valve closure; and ESS, end-systolic strain.