MYOCARDIAL CONTRACTILE FUNCTION IN AORTIC-STENOSIS AS DETERMINED FROM THE RATE OF STRESS DEVELOPMENT DURING ISOVOLUMIC SYSTOLE

To assess myocardial contractile function in the chronically hypertrophied human left ventricle, the rate of stress development ( dσ dt) as a function of developed stress (σD) during isovolumic systole was examined. Results for eight patients with aortic stenosis were compared with those for seven subjects with normal left ventricular function and with those for five patients with idiopathic congestive cardiomyopathy. The rate of stress development ( dσ dt) was nearly identical in patients with aortic stenosis and in normal subjects over a wide range of values of (σD) but was significantly lower in patients with cardiomyopathy (P < 0.01 versus control subjects and patients with aortic stenosis). Normal values for dσ/dt held not only for patients with compensated pressure overload, but also for those patients with aortic stenosis with depressed left ventricular ejection fraction and overt congestive failure. Similar findings were obtained when the first derivative of left ventricular pressure ( dP dt) was examined as a function of developed left ventricular pressure in normal subjects and patients with aortic stenosis or cardiomyopathy. These results indicate that contractile function as characterized by the isovolumic rate of stress development is not necessarily impaired in chronic pressure overload hypertrophy. © 1979.