title: Vector flow mapping in obstructive hypertrophic cardiomyopathy to assess the relationship of early systolic left ventricular flow and the mitral valve.
abstract: BACKGROUND
  The hydrodynamic cause of systolic anterior motion of the mitral valve (SAM) is unresolved.
  
  
  OBJECTIVE
  This study hypothesized that echocardiographic vector flow mapping, a new echocardiographic technique, would provide insights into the cause of early SAM in obstructive hypertrophic cardiomyopathy (HCM).
  
  
  METHODS
  We analyzed the spatial relationship of left ventricular (LV) flow and the mitral valve leaflets (MVL) on 3-chamber vector flow mapping frames, and performed mitral valve measurements on 2-dimensional frames in patients with obstructive and nonobstructive HCM and in normal patients.
  
  
  RESULTS
  We compared 82 patients (22 obstructive HCM, 23 nonobstructive HCM, and 37 normal) by measuring 164 LV pre- and post-SAM velocity vector flow maps, 82 maximum isovolumic vortices, and 328 2-dimensional frames. We observed color flow and velocity vector flow posterior to the MVL impacting them in the early systolic frames of 95% of obstructive HCM, 22% of nonobstructive HCM, and 11% of normal patients (p < 0.001). In both pre- and post-SAM frames, we measured a high angle of attack >60° of local vector flow onto the posterior surface of the leaflets whether the flow was ejection (59%) or the early systolic isovolumic vortex (41%). Ricochet of vector flow, rebounding off the leaflet into the cul-de-sac, was noted in 82% of the obstructed HCM, 9% of nonobstructive HCM, and none (0%) of the control patients (p < 0.001). Flow velocities in the LV outflow tract on the pre-SAM frame 1 and 2 mm from the tip of the anterior leaflet were low: 39 and 43 cm/s, respectively.
  
  
  CONCLUSIONS
  Early systolic flow impacts the posterior surfaces of protruding MVL initiating SAM in obstructive HCM.
authors.affiliation: Division of Cardiology, Mount Sinai Roosevelt and St. Luke's Hospitals, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Richard
authors.initials: R
authors.lastname: Ro
authors.affiliation: Division of Cardiology, Mount Sinai Roosevelt and St. Luke's Hospitals, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Dan
authors.initials: D
authors.lastname: Halpern
authors.affiliation: Division of Pediatric Cardiology, Oregon Health and Science University, Portland, Oregon.
authors.forename: David J
authors.initials: DJ
authors.lastname: Sahn
authors.affiliation: Division of Cardiology, Mount Sinai Roosevelt and St. Luke's Hospitals, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Peter
authors.initials: P
authors.lastname: Homel
authors.affiliation: Division of Cardiology, Mount Sinai Roosevelt and St. Luke's Hospitals, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Milla
authors.initials: M
authors.lastname: Arabadjian
authors.affiliation: Division of Cardiology, Mount Sinai Roosevelt and St. Luke's Hospitals, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Charles
authors.initials: C
authors.lastname: Lopresto
authors.affiliation: Division of Cardiology, Mount Sinai Roosevelt and St. Luke's Hospitals, Icahn School of Medicine at Mount Sinai, New York, New York. Electronic address: msherrid@chpnet.org.
authors.forename: Mark V
authors.initials: MV
authors.lastname: Sherrid
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D057446:Hydrodynamics; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology*; D013599:Systole / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: LVOT obstruction; echocardiography; hypertrophic cardiomyopathy; hypertrophic obstructive cardiomyopathy; vector flow map