Ermittlung ventrikulärer Druck-Geschwindigkeitskurven unter Berücksichtigung des enddiastolischen Druckes

Summary

The left ventricular pressure of anaesthetized cats was measured with a catheter-tip manometer. By using an analog computer, the quotients$\frac{{{{dp} \mathord{\left/ {\vphantom {{dp} {dt}}} \right. \kern-\nulldelimiterspace} {dt}}}}{p}$ and$\frac{{{{dp} \mathord{\left/ {\vphantom {{dp} {dt}}} \right. \kern-\nulldelimiterspace} {dt}}}}{{p - edp}}$ which are accepted to be directly proportional to the velocity of shortening of the contractile elements, were calculated and plotted versus pressure on axy-oscillograph in order to obtain instantaneous pressure-velocity curves. Pressure-velocity curves are nearly linear in their descending limb only when the total ventricular pressure and not the developed pressure is used for the measurement. When instead of the absolute pressure one uses the developed pressure for the calculation of velocity of shortening, the curves rise with a steep slope. The curves are similar to the force-velocity curves obtained with isolated papillary muscles, though a graphic calculation of velocity at zero pressure or enddiastolic pressure is not exactly possible.