Accession Number : ADP008922

Title :   Phase Locked LDA Measurements of Pulsatile Flow Through Heart Valves- A Novel Stability Approach,

Corporate Author : TEL-AVIV UNIV (ISRAEL) DEPT OF FLUID MECHANICS AND HEAT TRANSFER

Personal Author(s) : Bluestein, D. ; Einav, S.

Report Date : 23 JUL 1992

Pagination or Media Count : 7

Abstract : The presence of turbulence is blood flow through heart valves is indicative of valvular stenosis, depending on the phase of the cardiac cycle. Comparative studies of normal and stenosed valves show that maximum turbulence level is achieved during the decelerating phase (diastole). The spectra obtained during the rapid closure stage of the valves was found to be governed by dominant modes that stem from the stenosis geometry and the valve's leaflets vibrations. The traditional analysis of transition to turbulence draws upon a stability diagram where the fundamental heart rate is taken as a (the Wormersley parameter). A novel approach which involves the decomposition of alpha into its frequency components is suggested here. The novel stability approach distinguishes between stabilizing and destabilizing modes apparent in the flow and depicts an unbiased and accurate ability diagram of the flow. The traditional stability approach was found to be biased towards overrated unstable flow conditions, thus failing to represent an accurate flow stability criteria. (Author)

Descriptors :   *BLOOD CIRCULATION, *LASER ANEMOMETERS, DOPPLER SYSTEMS, PHASE LOCKED SYSTEMS, HEART, VALVES, STENOSIS, DIAGNOSIS(MEDICINE), UNSTEADY FLOW, PULSES, ISRAEL.

Subject Categories : Telemetry
      Anatomy and Physiology
      Medical Facilities, Equipment and Supplies
      Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE