Sarcomere distribution patterns in single cardiac cells.

Sarcomeres of single cardiac cells isolated either by microdissection or by enzymatic dissociation were visualized on a television screen, through the objective (63 X) of an inverted microscope and a television camera. A distinct line of the television picture was positioned on the preparation and the frequency content, corresponding to the dark and light areas of the striations was tracked by a phase-locked loop. This technique permitted the measurement of the length of successive sarcomeres and hence the sarcomere distribution pattern over the entire preparation.