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Published on: January 8, 2013
Distribution of coronary arterial capacitance in a canine model
A S Lader1, R S Smith, G C Phillips
1Department of Physiology, University of South Carolina School of Medicine, Columbia, South Carolina 29208, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|April 16, 1998
Summary
Investigating coronary artery capacitance in dog hearts revealed that increased pericardial pressure affects left anterior descending and left circumflex arteries differently, impacting their volume and pressure dynamics.
Area of Science:
- Cardiovascular Physiology
- Coronary Circulation Dynamics
Background:
- The capacitative properties of coronary arteries are crucial for maintaining adequate blood flow and pressure.
- Understanding how external pressures influence coronary capacitance is vital for diagnosing and treating cardiovascular conditions.
Purpose of the Study:
- To investigate the capacitative properties of the left main (LM), left anterior descending (LAD), and left circumflex (LCX) coronary arteries.
- To determine the effect of increased pericardial pressure (PCP) on coronary arterial capacitance.
Main Methods:
- Utilized ramp perfusion and a diastolic decay method in 19 open-chest isolated dog hearts.
- Experimentally altered transmural wall pressure by increasing pericardial pressure to 25 mmHg.
Main Results:
- Both methods indicated a minimal systolic capacitative component in coronary arteries.
- Increased PCP differentially affected LAD and LCX capacitance: LCX capacitance decreased (~13%), while LAD capacitance increased.
- No changes in conductance or zero flow pressure intercept were observed, refuting the waterfall theory at these PCP levels.
- Coronary arterial capacitance showed a linear relationship with perfusion pressure.
Conclusions:
- Pericardial pressure significantly influences coronary arterial capacitance, with distinct regional differences between LAD and LCX.
- The observed effects may be attributed to variations in intramural and epicardial volume distribution and intramural tension changes.
- Findings suggest that coronary vascular collapse (waterfall effect) is unlikely at moderate increases in pericardial pressure.
