title: Mitral valve coaptation and its relationship to late diastolic flow: A color Doppler and vector flow map echocardiographic study in normal subjects.
abstract: BACKGROUND
  Three competing theories about the mechanism of mitral coaptation in normal subjects were evaluated by color Doppler and vector flow mapping (VFM): (1) beginning of ventricular (LV) ejection, (2) "breaking of the jet" of diastolic LV inflow, and (3) returning diastolic vortices impacting the leaflets on their LV surfaces.
  
  
  RESULTS
  We analyzed 80 color Doppler frames and 320 VFM measurements. In all 20 normal subjects, coaptation occurred before LV ejection, 78±16 ms before onset. On color Doppler frames the larger anterior, and smaller posterior vortices circle back and, in all cases, strike the ventricular surfaces of the leaflets. On the first closing-begins frame, for the first time, vortex velocity normal to the ventricular surface of the anterior leaflet (AML) is greater than that in the mitral orifice, and the angle of attack of LV vortical flow onto the AML is twice as high as the angle of flow onto the valve in orifice. Thus, at the moment coaptation begins, vortical flow strikes the mitral leaflet with higher velocity, and higher angle of attack than orifice flow, and thus with greater force. According to the "breaking of the jet" theory, one would expect to see de novo LV flow perpendicular to the leaflets beginning after transmitral flow terminates. Instead, the returning continuous LV vortical flow that impacts the valve builds continuously after the P-wave.
  
  
  CONCLUSIONS
  Late diastolic vortices strike the ventricular surfaces of the mitral leaflets and contribute to valve coaptation, permitted by concomitant decline in transmitral flow.
authors.affiliation: Division of Cardiology, New York University Langone Medical Center, New York City, NY, USA.
authors.forename: Mark V
authors.identifier: http://orcid.org/0000-0003-4972-7780
authors.initials: MV
authors.lastname: Sherrid
authors.affiliation: Division of Cardiology, New York University Langone Medical Center, New York City, NY, USA.
authors.forename: Josef
authors.initials: J
authors.lastname: Kushner
authors.affiliation: Mount Sinai Roosevelt Hospital and Mount Sinai St. Luke's Hospital, Icahn School of Medicine at Mount Sinai, New York City, NY, USA.
authors.forename: Georgiana
authors.initials: G
authors.lastname: Yang
authors.affiliation: Mount Sinai Roosevelt Hospital and Mount Sinai St. Luke's Hospital, Icahn School of Medicine at Mount Sinai, New York City, NY, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Ro
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D003971:Diastole; D004452:Echocardiography / Q000379:methods*; D018618:Echocardiography, Doppler, Color / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: echocardiography; mitral regurgitation; mitral valve; mitral valve closure; physiology; regurgitation