In an experimental dog model, cardiac tamponade causes a fall in ventricular systolic pressures and the development of negative diastolic transmural pressures.
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.
Fowler et al. (Tue,) studied this question.