Background: The maximum rate of the ventricular pressure rise (dp/dt
max) provides a reliable measure of ventricular contractility. However, its estimation requires invasive measurement of left ventricular (LV) pressure, limiting its bedside clinical applicability. In the present study, 2 hypotheses were tested: (1)that the ratio of dp/dt
max between the aorta (Ao) and LV is consistent among patients despite marked differences in underlying cardiac disease, contractile state and heart rate when vascular mechanical and loading properties are taken into account, and (2)that using such a relationship, LV dp/dt
max can be estimated from Ao dp/dt
max, potentially providing a method of noninvasive determination of LV contractility.
Methods and Results: Data from 30 control children and 45 pediatric patients with various cardiovascular diseases revealed that the characteristic impedance (Zc) and mean arterial pressure were significant determinants of the Ao-LV dp/dt
max relationship in both control and disease groups. LV dp/dt
max estimated using the regression obtained in the control children (Ao dp/dt
max/LV dp/dt
max = 0.64+1.45*10
-4*Zc-3.73*10
-3*MAP, r=0.87) correlated well with the measured LV dp/dt
max in the disease group, including measurements taken after dobutamine and atrial pacing (r=0.89).
Conclusions: Ao dp/dt
max and LV dp/dt
max are closely correlated through the vascular loading properties and LV dp/dt
max can be derived from Ao dp/dt
max, which has potential as a noninvasive method of determining LV contractility. (
Circ J 2009;
73: 1698-1704)
View full abstract