Comparative investigations of right and left ventricular contractility in the rabbit.

In pentobarbitone-anaesthetized open-chest rabbits the left and right ventricular pressures were measured. The contractilities of the left and right ventricle were expressed by the contractility index CI = (dp/dt/p)max. Evaluation of left and right ventricular systolic pressure and CIs was done before and at aortic nerve stimulation as well as with pacing and without pacing of the heart. Pressures and CIs appear to be four times greater in the left ventricle than in the right one. The values of the pressure ratio LVSP/RVSP resp. CI ratio CILV/CIRV are adequate before and after aortic nerve stimulation. Any effect difference between the left and the right aortic nerve stimulation does not exist. In the paced heart the left and right ventricular pressure and the left ventricular CI are lower than without pacing. The effect time courses of the left and right ventricle appear to be adequate. Hence is follows that the left rabbit ventricle predominates in contraction development.