Left Ventricle: Role of the Pericardium and the Right Ventricle

IN CHRONIC CARDIAC DISEASE, the left ventricular diastolic pressure does not provide a reliable guide to the diastolic left ventricular volume,' and measurement of chamber volume, shape and wall thickness are necessary to identify changes in the myocardial stress-strain relation.' Under acute conditions, the stiffness of the left ventricular chamber progressively increases as passive diastolic filling occurs,3 but whether a single equation can describe this nonlinear pressure-volume curve in the human heart is not settled; this topic and the chronic adaptations that affect diastolic compliance have been examined in two recent reviews4'5 and will not be discussed here. Rather, certain factors that may be involved in acute displacements of the entire left ventricular pressurevolume curve will be considered, a phenomenon which is investigated in two clinical papers appearing in this issue of Circulation one concerned with pharmacologic interventions,6 the other with acute ischemia.7