E1A calculating unit for the determination of the peak measured contraction velocity of the contractile elements

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.