Impact of acute moderate elevation in left ventricular afterload on diastolic transmitral flow efficiency: analysis by vortex formation time.
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.
Jiamsripong
Panupong
P
Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona 85259, USA.
Calleja
Anna M
AM
Alharthi
Mohsen S
MS
Dzsinich
Mate
M
McMahon
Eileen M
EM
Heys
Jeffrey J
JJ
Milano
Michele
M
Sengupta
Partho P
PP
Khandheria
Bijoy K
BK
Belohlavek
Marek
M
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*