Measurement of Left Ventricular dp/dt by Simultaneous Doppler Echocardiography and Cardiac Catheterization

Left ventricular dp/dt is a useful isovolumic index for evaluating acute directional changes in myocardial contractility. To test the hypothesis that Doppler echocardiography can measure left ventricular dp/dt by using the mitral regurgitation velocity curve, 14 patients with at least a mild degree of mitral regurgitation (four with coronary artery disease, four with valvular heart disease, four with dilated cardiomyopathy, one with carcinoid, and one with mitral valve prosthesis) were studied by continuous-wave Doppler echocardiography. Simultaneously, left ventricular pressure was measured with a manometer-tipped catheter to generate actual dp/dt. Curves of left ventricular pressure and mitral regurgitant Doppler-derived velocities of three cardiac cycles were digitized at 1-msec intervals. The rate of Doppler-derived velocity increase was converted to a rate of pressure increase by using the modified Bernoulli equation. Mean dp/dt during various time intervals of the mitral regurgitation velocity envelope (1 to 2 m/sec, 2 to 3 m/sec, and 1 to 3 mlsec) corresponding to left ventricular-left atrial pressure differences of 12, 20, and 32 mm Hg, respectively, were calculated. Doppler-derived left ventricular dp/dt (y) correlated with catheter-derived left ventricular dp/dt (x) as follows: at the 1 to 2 m/sec interval, y (mm Hg/sec) = 0.84x + 137, r = 0.91, SEE = 90; at the 2 to 3 m/sec interval, y = l.1x - 89, r = 0.96, SEE = 80; and at the 1 to 3 m/sec interval, y = 1.1x + 23, r = 0.98, SEE = 50. We conclude that Doppler-derived left ventricular dp/dt at the 1 to 3 m/sec interval correlates best with catheter-derived left ventricular dp / dt. This new index along with other noninvasive information should improve hemodynamic evaluation.