Strain-rate of stretch affects crossbridge detachment kinetics during relaxation in twitching, intact cardiac trabeculae

Abstract

We have recently shown that Mechanical Control of Relaxation (MCR), or the acceleration of relaxation by fast stretch, exists in intact cardiac trabeculae. Relaxation mechanisms include both calcium and crossbridge kinetics, but early studies of MCR suggest that crossbridge detachment may be accelerated by fast stretch (strain-rate). This study was undertaken to investigate strain-rate dependent crossbridge kinetics after a ramp-stretch during the relaxation phase of a twitch in intact cardiac trabeculae.