Determinants of left ventricular filling and of the diastolic pressure-volume relation.

It is learned that many factors can affect left ventricular filling and the diastolic pressure-volume relation acutely, and the original concept that the pressure within the left ventricle is determined by the balance between the forces due to pressures within the ventricular cavity that expand the ventrical cavity and forcesDue to elasticity of the myocardium that resist this expan-

Abstract

U ntil the 1970s, the left ventricle was consid- ered an isolated shell in which the left ventricular diastolic pressure-volume relation depended on the myocardium's material properties and the left ventricle's wall thickness and geometry. According to this view, the relation between diastolic pressure and volume could change only in response to chronic changes in the cardiac muscle's material properties, such as scarring due to infarction, 1 or changes in cardiac geometry due to hypertrophy. As a consequence, the diastolic pressure-volume relation was considered unique over the short term. A practical application of this assumed uniqueness was that left ventricular diastolic pressure was used as a surrogate for volume in evaluating systolic function.