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Wave-intensity analysis: a new approach to coronary hemodynamics
Y H Sun1, T J Anderson, K H Parker
1Departments of Medicine and Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|September 28, 2000
Summary
Wave-intensity analysis reveals backward-going compression waves during ventricular contraction significantly impact coronary pressure and flow. Paired pacing amplifies these effects, influencing coronary hemodynamics.
Area of Science:
- Cardiovascular Physiology
- Hemodynamics
- Coronary Circulation
Background:
- Understanding coronary pressure and velocity determinants is crucial for diagnosing and treating cardiovascular diseases.
- Traditional methods may not fully capture the dynamic interplay of pressures and flows in the coronary arteries.
- Wave-intensity analysis (WIA) offers a novel approach to dissecting complex hemodynamic events.
Purpose of the Study:
- To utilize wave-intensity analysis (WIA) to identify the primary determinants of left circumflex coronary (LCx) pressure and velocity.
- To evaluate the impact of left ventricular contraction, particularly during paired pacing, on LCx hemodynamics.
- To differentiate between upstream (aortic) and downstream (microcirculatory) influences on coronary flow.
Main Methods:
- High-fidelity measurements of aortic (P(Ao)), left ventricular (P(LV)), and LCx (P(LCx)) pressures, and LCx velocity (U(LCx)) in 10 anesthetized dogs.
- Application of wave-intensity analysis (WIA) to pressure and velocity data.
- Comparison of hemodynamics under right atrial pacing (control), single right ventricular pacing, and paired right ventricular pacing.
Main Results:
- During isovolumic contraction, P(LCx) exceeded P(Ao), with paired pacing intensifying this pressure difference.
- Paired pacing significantly increased the P(LCx)-P(Ao) difference at crossover (DeltaP(X)) and average dP(LCx)/dt.
- WIA identified a backward-going compression wave (BCW) during isovolumic contraction that increased P(LCx) and decreased U(LCx); this BCW was augmented by paired pacing.
Conclusions:
- Wave-intensity analysis effectively distinguishes upstream and downstream influences on coronary hemodynamics.
- Backward-going compression waves during ventricular contraction play a significant role in modulating coronary pressure and flow.
- Altered ventricular contraction patterns, such as paired pacing, can exacerbate these wave phenomena, impacting coronary circulation.