The quest for a noninvasive, global index of left ventricular (LV) diastolic function has not yet been attained. Current echocardiographic methods extract components of diastolic function from selected aspects of transmitral flow velocity, ventricular geometry and wall motion. Diastolic left ventricular pressure P(t) and transmitral flow Q(t) define global diastolic impedance as Z(t) = P(t)/Q(t). Since P(t) requires cardiac catherization, we expressed P(t) via the nonsteady Bernoulli equation using Doppler echocardiographically measurable transmitral flow velocity v(t) and acceleration v = dv/dt. For validation we compared catheterization (invasively) derived Zinv(t) with echo (noninvasively) derived Znoninv(t) and found excellent agreement. We conclude that the echocardiographically determined LV diastolic impedance Znoninv(t) provides a physiologically sound quantitative index of global LV diastolic function. Further development and application in selected clinical groups is in progress.