[Effects of ventricular hypertrophy following experimental renovascular hypertension on the elasticity of the papillary muscle].

A precise method was developed for detecting muscular stiffness changes in the left ventricular hypertrophy by chronic pressure overload in rats (2 kidney-1 clip renal hypertensive rats). The technique of Quick-Release allowed the measurement of the "stress-strain" relation (delta-epsilon), the elastic stiffness (d delta/d epsilon) and the stiffness constant (K) in isolated papillary muscle from normal and hypertrophied hearts at rest and at the maximal time course of activation during isometric contraction. (Table: see text). The results of this study reported that the cardiac hypertrophy induced by experimental pressure overload was not associated with significant alteration of myocardial stiffness. So, it would seem that a muscular stiffness modification was unresponsible for the ventricular compliance change of clinical and experimental results.