A new method describing cross-sectional blood flow velocity profiles in the left ventricular outflow tract of patients with atrial fibrillation with the use of high-frame rate 2-dimensional color flow imaging.
A new Doppler method was developed to evaluate the instantaneous cross-sectional velocity profile variability in the left ventricular outlet tract in patients with atrial fibrillation. Blood flow velocities acquired at a high frame rate (>90 frames/s) from a single heart cycle were used to display the velocity profile. In 9 patients, 2 heart cycles with different R-R interval lengths were recorded in color flow mode in a transthoracic apical 5-chamber and long-axis view. Raw digital ultrasound data were analyzed with an external personal computer. The data indicated a variable skew in the profiles with the highest velocities and velocity-time integral (VTI) most often located in the center and toward the septum. The maximum VTI overestimated the mean VTI by approximately 40%. No significant difference existed between the two heartbeats. Thus the VTI can be averaged from heartbeats of different R-R lengths in atrial fibrillation.
Haugen
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Department of Cardiology and Lung Medicine, Norwegian University of Science and Technology, N-7006 Trondheim, Norway. Bjorn.O.Haugen@medisin.ntnu.no
Bjaerum
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Samstad
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Skjaerpe
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Torp
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D000328:Adult; D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D012815:Signal Processing, Computer-Assisted; D018615:Ultrasonography, Doppler, Color / Q000379:methods; D016277:Ventricular Function, Left