Dobutamine increased the slope of the dP/dtmax-end-diastolic volume relation to 358 +/- 94% of control, which was greater than the 244 +/- 61% increase in the end-systolic pressure-volume relation slope (P<0.005).
Does dobutamine or angiotensin II alter the left ventricular dP/dtmax-end-diastolic volume relation in closed-chest dogs?
In a canine model, dobutamine significantly increased the slope of the dP/dtmax-EDV relation more than the ESPVR, indicating it is a sensitive index of left ventricular contractility.
p-value: p=<0.005
I investigated the relation of the maximum rate of left ventricular pressure rise to the end-diastolic volume and the comparison of the maximum rate of left ventricular pressure rise-end-diastolic volume relation to the end-systolic pressure-volume relation, using the time-varying elastance model. These studies were performed in 11 dogs chronically instrumented to measure left ventricular pressure and determine left ventricular volume from three orthogonal dimensions. During vena caval occlusions, the relations between the maximum rate of left ventricular pressure rise and end-diastolic volume were described by straight lines (r = 0.97 +/- 0.01, mean +/- SD). Dobutamine increased the slope of the maximum rate of left ventricular pressure rise-end-diastolic volume relation to 358 +/- 94% of control. This increase was greater than the 244 +/- 61% increase in the slope of the end-systolic pressure-volume relation (P less than 0.005). The volume intercepts of the maximum rate of left ventricular pressure rise-end-diastolic volume relation and end-systolic pressure-volume relation were similar and were not significantly altered by dobutamine. The ratio of the slope of the maximum rate of left ventricular pressure rise-end-diastolic volume relation to the slope of the end-systolic pressure-volume relation divided by the time from end-diastole to end-systole was similar before (2.2 +/- 0.7) and after dobutamine (2.3 +/- 0.7, P = NS). Angiotensin II did not significantly alter the maximum rate of left ventricular pressure rise-end-diastolic volume relation generated by caval occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)
William C. Little (1985) studied Left ventricular mechanics (n=11). Dobutamine and Angiotensin II vs. Control (baseline) was evaluated on Relation of the maximum rate of left ventricular pressure rise to the end-diastolic volume and comparison to the end-systolic pressure-volume relation (p=<0.005). Dobutamine increased the slope of the dP/dtmax-end-diastolic volume relation to 358 +/- 94% of control, which was greater than the 244 +/- 61% increase in the end-systolic pressure-volume relation slope (P<0.005).