A new method for estimating left ventricular dP/dt by continuous wave Doppler-echocardiography. Validation studies at cardiac catheterization.

Abstract

In this study, we explored the use of continuous wave Doppler-echocardiography guided by color Doppler flow-mapping as a method for noninvasively calculating the rate of pressure rise (RPR) in the left ventricle. Continuous wave Doppler determination of the velocities in mitral regurgitant jets allows calculation of instantaneous pressure gradients between the left ventricle and the left atrium. Left atrial pressure variations in early systole can be considered negligible; therefore, the rising segment of the mitral regurgitation velocity curve should reflect left ventricular pressure increase. We studied 50 patients (mean age, 51 years; range, 25-66 years) in normal sinus rhythm with color Doppler-proven mitral regurgitation and compared the Doppler-derived left ventricular RPR with peak dP/dt obtained at cardiac catheterization. Doppler studies were performed simultaneously with cardiac catheterization in 11 patients and immediately before in the remaining cases. Two points were arbitrarily selected on the steepest rising segment of the continuous wave mitral regurgitation velocity curve (point A, 1 m/sec, point B, 3 m/sec), and the time interval (t) between them was measured. Following the Bernoulli relation, the pressure rise between points A and B is 32 mm Hg (4vB2-4vA2) and the RPR is 32 mm Hg/t. Results showed a linear correlation between the Doppler RPR and peak dP/dt (r = 0.87, SEE = 316 mm Hg/sec). The RPR in the left ventricle can be derived from the continuous wave Doppler mitral regurgitation velocity curve.