Sequence of shortening of the normal human left ventricle.

Left ventricular sequence of shortening was studied through the analysis of cineventriculograms in 30 degree right anterior oblique projection of 11 normal patients. In all patients transverse shortening progressed in base to apex direction, in a concentric fashion. Base descent started simultaneously with the first transverse inward motion and continued throughout systole.

[Right ventricle--pulmonary artery diastolic blood flow (author's transl)].

The authors show the possibility of the establishment of blood flow from the right ventricle to the pulmonary artery during the period of ventricular diastole, through experimental models mimetizing hemodynamic patterns described in the literature for certain cardiopathies. These models consisted of experimental hypodiastoly, associated or not with right ventricle hyposystoly. The detection of the existence or not of blood flow in the several phases of the cardiac cycle, was made recording the variations of the electrical impedance of the blood.

[Pre-systolic deflexion in pressure recordings of the right ventricle and pulmonary artery (author's transl)].

The authors demonstrated experimentally that the origin of the pre-systolic deflexion, previously observed by many investigators in pressure recordings of the right ventricle and the pulmonary artery, is due to the effective atrial contraction, which, besides the pressure change, produces a blood flow from the ventricle towards the artery. This flow must possibly exert an important role in the maintenance of the cardiac output when a failure of the right ventricle is established.

[An impedance measuring technique for blood flow qualitative recording].

An impedance measuring technique was developed for blood flow qualitative recordings in laboratory animals. Basically, it consists in the administration of an indicator solution (0,1 ml, NaCl 20%) which, mixing with the blood, provokes a decrease in its electrical resistance, in such way that the passage of this mixture (concentrated saline/blood) through a bipolar receptor electrode, resistively balanced by the electrical impedance of blood alone, will be detected as a sudden resistance fall. The results so far show that it is an adequate technique for blood flow qualitative studies, since, despite its simplicity, provides consistent and unequivocal recordings which, performed simultaneously with those of other circulatory events, may become a helpful tool for their understanding.