Mechanics of heart muscle during chronic cardiac hypertrophy

Abstract

Basic mechanical properties observed during cardiac hypertrophy were studied in left ventricular papillary muscle of Wistar rats: chronic overloading was induced by abdominal aortic stenosis, aorto-caval fistula, aortic insufficiency and abdominal aortic stenosis combined with aortic stenosis. Values of maximum unloaded velocity measured by zero-load-clamp technique were found lower in chronic pressure-overload than in chronic volume overload although the degree of cardiac hypertrophy was smaller in the former one than in the latter one. Furthermore, the time-independent force-velocity-length relationship during the contraction phase and loaddependence of relaxation were observed both in controls and in hypertrophied heart muscles, even during congestive heart failure.