Early systolic mitral leaflet "loitering" during acute ischemic mitral regurgitation.

摘要: Abstract Background : The mechanism by which incomplete mitral leaflet coaptation develops during ischemic regurgitation is debated, with recent studies suggesting that may be due to apically displaced papillary muscle tips. Yet quantitative in vivo three-dimensional motion has never been described. Methods: Radiopaque markers (sutured around the anulus, central free edges, and both tips bases) were imaged use of biplane videofluoroscopy six closed-chest, sedated sheep before (control) induction acute regurgitation. Leaflet was defined as minimum distance measured between edge control conditions. Results: During control, occurred 23 ± 7 msec (mean ± standard error mean) after end-diastole, when left ventricular pressure 27 6 mm Hg. regurgitation, delayed 115 ± 19 end-diastole ( p 0.01 {abs2}vs [ n  = 4]) 88 4 At anulus area 14% 2% larger than (7.4 ± 0.3 cm 2 vs 6.5 ± 0.2 , 0.005) result lengthening muscular annular regions (76.0 ± 2.5 70.5 ± 1.4 mm, 0.01). Mitral shape (ratio two diameters) at more circular (0.79 ± 0.71 ± 0.02, 0.02 control), but there no apical displacement either tip. Conclusions: Incomplete early systole, not end-systole, "loitering" leaflets associated posterior enlargement circularization, well some posterolateral, apical, tip displacement. These data suggest systolic dilatation change altered are primary mechanisms occurs (J Thorac Cardiovasc Surg 1998;116:193-205)