The normal and diseased pericardium: Current concepts of pericardial physiology, diagnosis and treatment

Abstract

The past quarter century has seen remarkable contributions to understanding the role of the pericardium in health and disease and to diagnostic methods in the context of significant changes in the clinical spectrum of acute pericarditis, pericardial effusion and their sequelae. Anatomic studies have demonstrated pericardial ultrastructure and its relation to function and delineated the pericardial lymphatics and their participation in inflammation and tamponade. Physiologic investigations have revealed the pericardium's mechanical, membranous and ligamentous functions and its role in ventricular interaction, pericardial modification of cardiac responses during acute cardiocirculatory loading and effects on diastolic function (and, at high filling pressures, systolic function), including reduction by pericardial fluid of true filling pressure—the myocardial transmural pressure. The diastolic mean pressure plateau and phasic venoatrial pressure and flow during cardiac tamponade have been further characterized and the mechanisms producing pulsus paradoxus have been elucidated, including the importance of inspiratory increase in right ventricular filling. A far reaching compensatory response to tamponade has been revealed, particularly adrenergic stimulation, and, over time, blood volume expansion. Right heart tamponade and low pressure tamponade have been identified and the importance of the pericardium in the restrictive dynamics of right ventricular myocardial infarction has been demonstrated. Constrictive pericarditis, And the currently more common effusive-constrictive pericarditis, have been studied, in depth, clinically and hemodynamically. Cardiography in pericardial disease now includes M-mode and two-dimensional echographic studies, enabling rapid diagnosis and further physiologic study in cardiac tamponade and constriction. The four stages of typical electrocardiographic evolution in acute pericarditis and atypical variants have been codified and characteristic PR segment deviations identified. The non-etiologic role of acute pericarditis in arrhythmias has been clarified in prospective clinical and postmortem investigations. Electric alternation has been elucidated and its relation to cardiac "swinging" has been at least partly explained. Special roles now exist for contrast roentgenography, computed tomography (especially for cysts) and radionuclide imaging. Clinical advances in pericardial disease include changes in the prevalence of established etiologies and identification of new etiologies, for example, immunopathic processes to explain recurrent pericarditis and the post-injury (including postoperative) pericardial syndromes. New forms of constriction—uremic, postoperative, radiation—have appeared in increasing numbers. The pericardial rub has been characterized and codified, confirming a typical three-component structure (with frequent exceptions). © 1983, American College of Cardiology Foundation. All rights reserved.