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Factors affecting the end-systolic pressure-volume relationship
Federation Proceedings
|June 1, 1984
Summary
The end-systolic pressure-volume relationship (ESPVR) is crucial for cardiac performance. Changes in afterload, coronary artery pressure, and ischemia significantly impact ESPVR, affecting cardiac function and requiring multiple data points for accurate assessment.
Area of Science:
- Cardiovascular Physiology
- Cardiac Mechanics
Background:
- The end-systolic pressure-volume relationship (ESPVR) is a key determinant of systolic performance in the heart.
- Understanding factors influencing ESPVR is vital for assessing cardiac function under various physiological and pathological conditions.
Purpose of the Study:
- To investigate the effects of altered afterload impedance, coronary artery pressure (CAP), and regional ischemia on the ESPVR in an isolated canine heart model.
- To determine how these factors influence the slope and intercept of the ESPVR.
Main Methods:
- Utilized an isolated cross-circulated canine heart preparation.
- Manipulated afterload impedance (resistance, characteristic impedance), coronary artery pressure (CAP), and induced regional ischemia.
- Measured pressure-volume data points to analyze the ESPVR.
Main Results:
- Afterload impedance changes did not alter the ESPVR slope but could cause slight leftward shifts.
- ESPVR remained unchanged with CAP above a critical value; decreased CAP progressively reduced the ESPVR slope.
- Regional ischemia induced nonlinearity and a downward shift in ESPVR, proportional to the ischemic area.
Conclusions:
- Accurate ESPVR assessment requires at least three pressure-volume points to ensure linearity and characterize both slope and volume intercept.
- Coronary artery pressure and regional ischemia are significant modulators of cardiac systolic performance as reflected by ESPVR.