title: Impact of acute moderate elevation in left ventricular afterload on diastolic transmitral flow efficiency: analysis by vortex formation time.
abstract: BACKGROUND
  The formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. Vortex formation time (VFT) is an index of the optimal conditions for vortex formation. It was hypothesized that left ventricular (LV) afterload impairs diastolic transmitral flow efficiency and therefore shifts the VFT out of its optimal range.
  
  
  METHODS
  In 9 open-chest pigs, LV afterload was elevated by externally constricting the ascending aorta and increasing systolic blood pressure to 130% of baseline value for 3 minutes.
  
  
  RESULTS
  Systolic LV function decreased, diastolic filling velocity increased only during the late (atrial) phase from 0.46 +/- 0.06 to 0.63 +/- 0.19 m/s (P = .0231), and end-diastolic LV volume and heart rate remained unchanged. VFT decreased from 4.09 +/- 0.27 to 2.78 +/- 1.03 (P = .0046).
  
  
  CONCLUSIONS
  An acute, moderate elevation in LV afterload worsens conditions for diastolic vortex formation, suggesting impaired blood transport efficiency.
authors.affiliation: Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona 85259, USA.
authors.forename: Panupong
authors.initials: P
authors.lastname: Jiamsripong
authors.forename: Anna M
authors.initials: AM
authors.lastname: Calleja
authors.forename: Mohsen S
authors.initials: MS
authors.lastname: Alharthi
authors.forename: Mate
authors.initials: M
authors.lastname: Dzsinich
authors.forename: Eileen M
authors.initials: EM
authors.lastname: McMahon
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Heys
authors.forename: Michele
authors.initials: M
authors.lastname: Milano
authors.forename: Partho P
authors.initials: PP
authors.lastname: Sengupta
authors.forename: Bijoy K
authors.initials: BK
authors.lastname: Khandheria
authors.forename: Marek
authors.initials: M
authors.lastname: Belohlavek
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003198:Computer Simulation; D004452:Echocardiography / Q000379:methods*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000502:physiology*; D008955:Models, Cardiovascular; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*