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Varying elastance concept may explain coronary systolic flow impediment
R Krams1, P Sipkema, N Westerhof
1Laboratory for Physiology, Free University, Amsterdam, The Netherlands.
The American Journal of Physiology
|November 1, 1989
Summary
Left ventricular systolic pressure has a minimal impact on coronary blood flow amplitude. This suggests that pressure alone does not solely determine coronary flow, supporting the time-varying elastance model.
Area of Science:
- Cardiovascular Physiology
- Hemodynamics
Background:
- Coronary blood flow is crucial for myocardial function.
- Understanding the determinants of coronary inflow is essential for diagnosing and treating cardiac conditions.
Purpose of the Study:
- To investigate the relationship between left ventricular systolic pressure and phasic arterial coronary inflow.
- To test the hypothesis that left ventricular pressure is the sole determinant of coronary flow.
Main Methods:
- Measurements of phasic arterial coronary inflow in a blood-perfused isolated cat heart.
- Varying systolic left ventricular pressure under controlled conditions (constant perfusion pressure, vasomotor tone, and heart rate).
- Analysis of normalized flow amplitude (A) in relation to systolic pressure (Ps).
Main Results:
- A weak correlation was found between left ventricular systolic pressure and normalized coronary flow amplitude (A = 0.70 +/- 0.15 + 0.005 +/- 0.005 Ps).
- The hypothesis that left ventricular pressure solely impedes coronary flow was not supported.
- The observed data align with the time-varying elastance concept.
Conclusions:
- Left ventricular systolic pressure is not the sole determinant of coronary flow.
- The time-varying elastance model provides a suitable framework for explaining coronary flow dynamics.
- Both intravascular and luminal compartments are subject to time-varying elastance, influencing coronary flow similarly across different beat types.