The pathophysiology of cardiac tamponade is welldescribed.
Briefly, increased intrapericardial pressure limits
venous return to the heart and causes right ventricular
compression. There is a progressive decline in right
ventricular end-diastolic volume as diastolic filling lessens,
worsening cardiac output. In severe tamponade, venous
return during inspiration into the compressed right ventricle
bows the interventricular septum into the left ventricle,
further diminishing systemic cardiac output. As pericardial
pressure increases and surpasses ventricular end-diastolic
pressure, the ventricular volumes grow smaller and smaller
and cardiac output worsens