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Effects of platelet-activating factor on left ventricular performance in dogs
T Tamura1, T Iwasaka, Y Takayama
1Cardiovascular Center, Kansai Medical University, Osaka, Japan.
Japanese Circulation Journal
|February 1, 1997
Summary
Platelet-activating factor (PAF) reduces cardiac output by decreasing preload, contractility, and increasing arterial load. While relaxation is prolonged, passive diastolic chamber stiffness appears unaffected.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
- Hemodynamics
Background:
- Platelet-activating factor (PAF) is implicated in cardiovascular regulation.
- Understanding PAF's impact on cardiac function is crucial for managing cardiovascular conditions.
Purpose of the Study:
- To investigate the precise mechanisms by which PAF influences cardiac output (CO).
- To evaluate the effects of PAF on left ventricular (LV) performance and hemodynamics.
Main Methods:
- Utilized a left ventricular (LV) pressure-volume model in anesthetized dogs.
- Measured LV volume via conductance catheter and LV pressure via manometer-tipped catheter.
- Assessed LV performance parameters including contractility (Ees), stroke work (Mw), arterial load (Ea), and relaxation (T).
Main Results:
- PAF administration led to decreased LV end-diastolic volume and pressure, end-systolic pressure, maximum dP/dt, and CO.
- Significant reductions in Ees and Mw, decreased minimum dP/dt, and prolonged relaxation time constant (T) were observed.
- Increased arterial load (Ea) and altered diastolic properties (leftward shift of EDPVRs) were noted.
Conclusions:
- PAF decreases cardiac output by reducing preload and contractility.
- Increased arterial load and prolonged relaxation contribute to PAF's effects on cardiac function.
- Passive diastolic chamber stiffness is likely not significantly affected by PAF, despite relaxation changes.