Normal ventricular ejection dynamics in man during rest and exercise

In order to understand the hemodynamic basis for ejection murmurs, the characteristics of normal ventricular ejection dynamics during rest and exercise are reviewed. A simplified theoretical model of the physical principles of resistance, inertia, and compliance is presented to define those significant factors which contribute to peripheral impedance. Using new multisensor catheterization techniques, the first reliable measurements in man of the physiologic pressure gradients between the left ventricle and aorta, and the right ventricle and pulmonary artery are reported. The relationships of the left ventricular aortic gradient (impulse gradient) to the simultaneously measured aortic flow velocity during rest and exercise are discussed in terms of the basic laws of Newtonian physics. The important role of inertia in early systolic ejection is emphasized. The systolic time intervals of both flow velocity and pressure events in seven normal patients are also reported for both the rest and exercise states. The differences between right and left sided ejection characteristics are discussed. The principles reviewed and the data presented should lead to a better understanding of the role of the peripheral circulation in determining the character of ventricular ejection.