title: Fixed-apex mitral annular descent correlates better with left ventricular systolic function than does free-apex left ventricular long-axis shortening.
abstract: Echocardiographic measures of mitral annular descent (MAD) assume a fixed left ventricular (LV) apex throughout the cardiac cycle, ignoring the apical component of LV long-axis shortening (LAS). We tested whether apical motion contributes significantly to LAS, making LAS a better surrogate of LV systolic function than MAD. Three-dimensional LV systolic MAD, LAS, and apical motion were measured in sheep using implanted radiopaque markers and biplane videofluoroscopy. End-diastolic volume-stroke work relationship (preload recruitable stroke work) was computed as a load-independent index of LV systolic function. Apical motion was 1.4 +/- 0.8 mm, representing 22% of LAS (P <.05). Linear regression demonstrated that MAD correlated slightly better with preload recruitable stroke work (r = 0.808) than LAS (r = 0.792, both P <.001). Receiver operating characteristic curves demonstrated MAD was more accurate in predicting depressed LV function than LAS (93% vs 84%, respectively). Although LV apical motion contributed significantly to LAS, MAD measured with a fixed-apex assumption, as currently done echocardiographically, correlated more closely with LV preload recruitable stroke work.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Filiberto
authors.initials: F
authors.lastname: Rodriguez
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Tibayan
authors.forename: Julie R
authors.initials: JR
authors.lastname: Glasson
authors.forename: David
authors.initials: D
authors.lastname: Liang
authors.forename: George T
authors.initials: GT
authors.lastname: Daughters
authors.forename: Neil B
authors.initials: NB
authors.lastname: Ingels
authors.forename: D Craig
authors.initials: DC
authors.lastname: Miller
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization / Q000379:methods*; D002315:Cardiopulmonary Bypass; D004195:Disease Models, Animal; D005471:Fluoroscopy / Q000379:methods; D006331:Heart Diseases / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008943:Mitral Valve / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D011312:Pressure; D012372:ROC Curve; D012756:Sheep; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology*; D014741:Video Recording