Transmural Ventricular Pressures in Experimental Cardiac Tamponade

Experimental cardiac tamponade was produced in open-chest dogs. Left and right ventricular systolic pressures fell when intrapericardial pressure was increased only a few millimeters of mercury. Negative diastolic transmural pressures of 1 to 6 mm. Hg developed in the left ventricle and negative diastolic transmural pressures of 2 to 8.5 mm. Hg developed in the right ventricle. In some instances the period of right ventricular systolic ejection was greatly abbreviated at higher levels of intrapericardial pressure.