Noninvasive evaluation of diastolic function: Need for hemodynamically and clinically relevant variables

Abstract

Radionuclide angiography and echocardiography provide accurate clinical assessment of systolic left ventricular function. In contrast, although several noninvasive variables of diastolic function have been proposed, none are routinely employed in clinical practice. This is unfortunate because symptoms and signs of congestive heart failure are often caused by diastolic rather than systolic dysfunction, especially in patients with hypertension, hypertrophic and restrictive cardiomyopathy and pericardial constriction. Recognition of diastolic dysfunction in the absence of systolic dysfunction is important because of the differences in appropriate patient management (I). Assessment of diastolic ventricular function. Clinical application of diastolic functional indexes has been hampered by a lack of investigator agreement on optimal variables, questions of load dependence of these indexes and uncertainty over which variables best predict clinical outcome (2). The assessment of diastolic function is usually classified into three components: ventricular relaxation, chamber stiffness and myocardial stiffness (3). Ventricular relaxation is best described by isovolumetric relaxation indexes such as negative rate of rise in pressure (-dP/dt) and 7. Assessment of the passive elastic properties of the ventricle (chamber and muscle stiffness) requires accurate simultaneous measurement of pressure and volume. Chamber stiffness is generally defined as the change in pressure relative to a change in chamber volume (dP/dV). Its reciprocal is chamber compliance. The ratio dP/dV is load dependent and increases exponentially with volume, the slope of the relation being used as a hemodynamic index of chamber stiffness. Myocar-