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Extracardiac pressure and ventricular haemodynamics.
J S Janicki1, K T Weber, J Loscalzo
1Department of Medicine, University of Pennsylvania, Philadelphia.
Cardiovascular Research
|March 1, 1987
Summary
Pericardial pressure significantly impacts left ventricular filling more than intrathoracic pressure. Right ventricular filling is similarly affected by both external pressures.
Area of Science:
- Cardiovascular Physiology
- Thoracic Pressure Dynamics
Background:
- Understanding how external pressures affect cardiac function is crucial for clinical management.
- Pericardial and intrathoracic pressures can alter ventricular filling and systolic pressures.
Purpose of the Study:
- To compare the relative influences of pericardial and intrathoracic pressures on ventricular diastolic and systolic function.
- To elucidate the sensitivity of the left and right ventricles to different external thoracic pressures.
Main Methods:
- Two experimental groups of dogs were studied: one with induced pericardial effusion (open chest) and another with induced pneumothorax (closed chest).
- Ventricular pressures and volumes were monitored under controlled conditions of external pressure, transpulmonary pressure, and lung volume.
Main Results:
- Both right and left ventricular diastolic pressures showed linear responses to external pressures, with varying slopes between groups.
- The left ventricle exhibited greater volume reduction with increased pericardial pressure (slope 0.39) compared to intrathoracic pressure.
- Left ventricular systolic pressure decreased more significantly with pericardial effusion, while right ventricular systolic pressure responses differed between the two groups.
Conclusions:
- Right ventricular filling is not significantly differentially affected by pericardial versus intrathoracic pressure.
- The left ventricle, particularly its filling pressure gradient, is more sensitive to changes in pericardial pressure than intrathoracic pressure.