Relation of negative intraventricular pressure to ventricular volume.

Elastic forces of the ventricular walls produce a subatmospheric (negative transmural) pressure in the empty quiescent ventricle of open chest dogs. As fluid is added to the ventricle the negative intraventricular transmural pressures become 0 and finally positive. The resulting ventricular pressure-volume curves are S-shaped, having one limb in the negative and another in the positive pressure range. It is concluded that previously reported suction and negative intraventricular transmural pressures lasting throughout the entire diastole in ventricles with small residual volumes are caused by elastic forces which also prevail under static conditions.