Peak aortic flow and acceleration as indices of ventricular performance in the dog.

Abstract

Abstract Six anesthetized intact dogs were studied during several interventions to alter ventricular performance while peak aortic blood flow (PF) and maximal acceleration of aortic blood flow (max dFdt) were computed from electromagnetic flow probe signals. Both peak flow and max dFdt were demonstrated to be sensitive indices of ventricular performance during induced alterations in the inotropic state (isoproterenol, fluothane, and propranolol) and in preload (volume expansion and hemorrhage), but showed only modest and variable changes in response to increased heart rate (atrial pacing) or to increased afterload (phenylephrine). Aortic max dFdt also showed a significant direct correlation with left ventricular max dpdt and both of these variables were demonstrated to be responsive to alterations in load and inotropic state. Peak flow and max dFdt correlated well under all experimental conditions with the performance indices: stroke volume, mean ejection rate, stroke work, and peak power. The ratio of max dFdt to peak flow and the time from onset of ejection to peak flow demonstrated little response to preload or afterload and may be useful as indices of ventricular contractile state.