EFFECT OF AORTIC-VALVE STENOSIS (PRESSURE OVERLOAD) AND REGURGITATION(VOLUME OVERLOAD) ON LEFT-VENTRICULAR SYSTOLIC AND DIASTOLIC FUNCTION

In secondary hypertrophy from chronic pressure or volume overload, or both, systolic as well as diastolic abnormalities of left ventricular (LV) function have been described, but their relation has not been def ined. In 58 patients with aortic valve disease (28 with aortic valve s tenosis, and 30 with aortic regurgitation) and in 11 control subjects, LV biplane cineangiography was performed simultaneously with LV high- fidelity pressure measurements. LV ejection performance was assessed b y ejection fraction, and diastolic function by the time constant of LV pressure decay, the early and late peak filling rates, and the consta nts of chamber (pressure-volume relation) and myocardial stiffness (st ress-strain relation). In the entire cohort (n = 69), ejection fractio n was inversely related to the time constant of LV relaxation (r = -0. 58, p < 0.001) and to the constant of myocardial stiffness (r = -0.62, p < 0.001). Despite preserved systolic contractile function (as evalu ated from the ejection fraction-mean systolic stress relation), abnorm alities in LV diastolic function were present in 9 of 18 patients with pressure overload and 20 of 22 with volume overload. None of the 58 p atients with aortic valve disease had a reduced early peak filling rat e, whereas a reduction in late peak filling rate was observed in 3 wit h aortic stenosis, but in none with aortic regurgitation. Thus, it app ears that abnormalities of relaxation and passive diastolic myocardial stiffness precede alterations in myocardial contractility. Assessment of peak filling rates is not helpful to detect diastolic dysfunction in patients with aortic valve disease.