Noninvasive evaluation of contractile state by left ventricular dP/dtmax divided by end-diastolic volume using continuous-wave Doppler and M-mode echocardiography.

The maximum rate of left ventricular (LV) pressure rise (dP/dtmax) is commonly used in the assessment of directional change in LV contractility and, recently, estimated by analyzing continuous-wave Doppler ultrasound velocity curve of mitral regurgitation. As an alteration in ventricular preload is known to affect dP/dtmax, normalized dP/dtmax for preload might be more reliable to assess LV contractile state. To investigate the usefulness of a new index of LV contractile state determined by continuous-wave Doppler analysis of mitral regurgitation and M-mode echocardiogram-derived LV end-diastolic volume, we studied 18 patients with mild mitral regurgitation. The continuous-wave Doppler velocity curves of mitral regurgitation were digitized and converted to instantaneous pressure gradient between the LV and left atrium using the simplified Bernoulli equation. The maximum value of its first derivative (Doppler-derived dP/dtmax) correlated well with LV dP/dtmax using simultaneously recorded LV pressures by manometer-tipped catheter (n = 20, r = 0.97, p < 0.001). Corrected Doppler-derived dP/dtmax for LV end-diastolic volume using Teichholz's method significantly increased by inotropic stimulation with dobutamine (p < 0.01); however, it remained unchanged by augmentation of afterload with angiotensin II. Thus, the LV dP/dtmax can be accurately estimated in humans by analyzing the continuous-wave Doppler velocity curve of mitral regurgitation, and corrected Doppler-derived dP/dtmax for LV end-diastolic volume is relatively independent of loading alteration and sensitive to inotropic stimulation. We concluded that echocardiographic assessment by combined Doppler- and M-mode measurements provides a useful and sensitive index of LV contractile state noninvasively.