The Effects of Sarcomere Length on Force and Velocity of Shortening in Cardiac Muscle

The relation between peak force (F) during contraction, velocity of shortening (V) and sarcomere length (SL) determine cardiac pump function. We have studied the factors that control force and velocity of shortening were studied in trabeculae dissected from normal or hypertrophied right ventricles of rats in modified Krebs-Henseleit solution at 26 C, in which Ca2+ or pH was varied. Hypertrophy (H) was induced by triiodothyronine injections (Ht), by vigorous physical exercise during swimming (Hs) or by hypobaric hypoxia (Hh).