Physiologic role of the normal pericardium.
Because of the characteristics of the parietal pericardial tissue, the intact pericardial sac has a limited reserve volume, becoming relatively non-compliant when the heart volume is at the high end of the normal physiologic range. Pericardial restraint of the heart is best considered as a contact force. Measured with flattened balloons, the magnitude of pericardial contact pressure is probably several mmHg less than right atrial pressure. The diastolic pressure-volume relationship of the right ventricle, and to a lesser degree of the left ventricle, shifts downward following pericardiectomy. In dogs, the pericardium has been shown to limit maximal cardiac output. Some disease states associated with a rapid increase in total heart volume, including subacute mitral regurgitation and right ventricular infarction, demonstrate an increased pericardial influence on cardiac filling.
Watkins
M W
MW
Department of Medicine, University of Vermont College of Medicine, Burlington 05405.
LeWinter
M M
MM
D000818:Animals; D002302:Cardiac Output / Q000502:physiology; D002306:Cardiac Volume / Q000502:physiology; D006331:Heart Diseases / Q000503:physiopathology; D006801:Humans; D010496:Pericardium / Q000033:anatomy & histology / Q000502:physiology*; D016276:Ventricular Function / Q000502:physiology