E1A calculating unit for the determination of the peak measured contraction velocity of the contractile elements.
Bussmann Wd, B Joss, Martin Kaltenbach · PubMed · 1975
An analog calculating unit is described, which is able to differentiate the left ventricular pressure and divide dP/dt by P, where P is the absolute pressure value. The parameter dP/dt/P is called the peak measured velocity (Vpm) with the dimension s(-1). The unit has an appropriate accuracy for division, three ranges and easy to handle calibration steps. The time constants for the various ranges are 40, 8 and 4 ms.