Mechanical parameters determined in dispersed ventricular heart cells.

A high-resolution laser diffraction system suitable for studying the basic mechanical properties of small contractile single cells has been developed. This method was used to establish the mechanical behavior of 95 ventricular cells isolated from adult guinea pig hearts. During contraction, the sarcomere length shortened from 1828 +/- 43 nm (mean +/- SD) to 1518 +/- 99 nm. The maximal velocities were 1.98 +/- 0.64 micron/s for shortening and 1.93 +/- 0.54 micron/s for re-lengthening. The twitch duration from 20% shortening to 80% re-lengthening was 622 +/- 120 ms.