Cardiac tamponade: hemodynamic observations in man.

Abstract

SUMMARY Hemodynamic studies were performed before and after pericardiocentesis in 19 patients with pericardial effusion. Right atrial pressure decreased significantly, from 16 ± 4 mm Hg (mean ± SD) to 7 ± 5 mm Hg in 14 patients with cardiac tamponade. This change was accompanied by significant increases in cardiac output (3.87 ± 1.77 to 7 ± 2.2 I/min) and inspiratory systemic arterial pulse pressure (45 ± 29 to 81 ± 23 mm Hg). The remaining five patients did not demonstrate cardiac tamponade, as evidenced by lack of significant change in these hemodynamic parameters.In all patients with tamponade, right ventricular end-diastolic pressure (RVEDP) was elevated and equal to pericardial pressure; equilibration was uniformly absent in patients without tamponade. During gradual fluid withdrawal in the tamponade group, significant hemodynamic improvement was largely confined to the period when right ventricular filling pressure remained equilibrated with pericardial pressure. In 10 patients with tamponade and pulsus paradoxus, pulmonary arterial wedge pressure (PAW) was equal to pericardial pressure except during early inspiration and expiration when it was transiently less and greater, respectively; however, inspiratory right atrial pressure never fell below pericardial pressure. In these 10 patients, PAW decreased significantly following pericardiocentesis (P < 0.001). In the remaining four patients with tamponade but without pulsus paradoxus, all of whom had chronic renal failure, PAW was consistently higher than pericardial pressure or RVEDP and did not decrease after pericardiocentesis.These data tend to confirm the hypothesis that in patients with tamponade, the venous pressure required to maintain any given cardiac volume is determined by pericardial rather than ventricular compliance. When pericardial compliance determines diastolic pressure in both ventricles, relative filling of the ventricles will be competitive and determined by their respective venous pressures (pulmonary vs systemic), which vary with respiration and alternately favor right and left ventricular filling. This results in pulsus paradoxus. However, if pulmonary arterial wedge pressure is markedly elevated before the onset of tamponade, as in patients with chronic renal failure, then pericardial compliance may only determine right ventricular filling pressure. In such cases, pulsus paradoxus may be absent. MUCH OF OUR

Cardiac tamponade in left ventricular dysfunction.

“…[1][2][3][4][5][6][7][8][9][13][14][15] The present study demonstrates distinctive hemodynamic features and echocardiographic manifestations of experimental cardiac tamponade in the presence of ischemic left ventricular dysfunction. The absence of pulsus paradoxus and the altered manner in which the cardiac chambers are compressed aid our understanding of the pathophysiology of cardiac tamponade and its clinical signs.…”

“…Pulsus paradoxus and echocardiographic evidence of right atrial and right ventricular collapse are useful signs because they may differentiate hemodynamically insignificant pericardial effusion from cardiac tamponade.1-5 However, clinical observations suggest that pulsus paradoxus may be absent in patients with left ventricular dysfunction and elevated left ventricular filling pressure. 1,6 In addition, although it has been reported that right ventricular diastolic collapse is sensitive to alterations in ventricular load,7,8 little is known about the effects of left ventricular dysfunction on chamber collapse during cardiac tamponade. These gaps in our knowl-edge are particularly relevant in view of the increasing numbers of patients with cardiac tamponade and coexisting cardiovascular disease.9 Accordingly, we studied cardiac tamponade in an animal model of ischemia-induced left ventricular failure to test the hypothesis that pulsus paradoxus is not present when cardiac tamponade occurs with concomitant left ventricular dysfunction manifested by elevated left ventricular filling pressure.…”

Pericardial Disease

“…[33][34][35][36] The volume in any cardiac chamber can only increase when there is an equal decrease in the volume in other chambers. Thus, venous return and atrial filling predominantly occur during ventricular systole as the ejection of blood out of the right and left ventricles lowers cardiac volume and allows blood to enter the atria.…”

Exacerbated Tamponade: Deterioration of Cardiac Function by Lowering Excessive Arterial Pressure in Hypertensive Cardiac Tamponade

“…More grad ual fluid accumulation, 'medical tamponade', permits time for complex cardiocirculatory mechanisms, includ ing increased blood volume, to support systemic arterial pressure for longer periods [1]. Although uncommon, grossly elevated blood pressure despite cardiac tampon ade is well known [3][4][5][6]. Exacerbation of pulsus para doxus by effective antihypertensive therapy has notewor thy physiologic implications.…”