title: Characterization of common carotid artery blood-flow waveforms in normal human subjects.
abstract: Knowledge of human blood-flow waveforms is required for in vitro investigations and numerical modelling. Parameters of interest include: velocity and flow waveform shapes, inter- and intra-subject variability and frequency content. We characterized the blood-velocity waveforms in the left and right common carotid arteries (CCAs) of 17 normal volunteers (24 to 34 years), analysing 3560 cardiac cycles in total. Instantaneous peak-velocity (Vpeak) measurements were obtained using pulsed-Doppler ultrasound with simultaneous collection of ECG data. An archetypal Vpeak waveform was created using velocity and timing parameters at waveform feature points. We report the following timing (post-R-wave) and peak-velocity parameters: cardiac interbeat interval (T(RR)) = 0.917 s (intra-subject standard deviation = +/- 0.045 s); cycle-averaged peak-velocity (V(CYC)) = 38.8 cm s(-1) (+/-1.5 cm s(-1)); maximum systolic Vpeak = 108.2 cm s(-1) (+/-3.8 cm s(-1)) at 0.152 s (+/-0.008 s); dicrotic notch Vpeak = 19.4 cm s(-1) (+/-2.9 cm s(-1)) at 0.398 s (+/-0.007 s). Frequency components below 12 Hz constituted 95% of the amplitude spectrum. Flow waveforms were computed from Vpeak by analytical solution of Womersley flow conditions (derived mean flow = 6.0 ml s(-1)). We propose that realistic, pseudo-random flow waveform sequences can be generated for experimental studies by varying, from cycle to cycle, only T(RR) and V(CYC) of a single archetypal waveform.
authors.affiliation: Imaging Research Laboratories, The John P Robarts Research Institute, London, Ontario, Canada.
authors.forename: D W
authors.initials: DW
authors.lastname: Holdsworth
authors.forename: C J
authors.initials: CJ
authors.lastname: Norley
authors.forename: R
authors.initials: R
authors.lastname: Frayne
authors.forename: D A
authors.initials: DA
authors.lastname: Steinman
authors.forename: B K
authors.initials: BK
authors.lastname: Rutt
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005260:Female; D005583:Fourier Analysis; D006334:Heart Function Tests; D006339:Heart Rate; D006801:Humans; D008297:Male; D018617:Ultrasonography, Doppler, Pulsed