Extrinsic Versus Intrinsic Determinants of the Diastolic Pressure—Volume Relation

摘要: The left-ventricular diastolic pressure—volume relation (LV-DPVR) is determined by intrinsic properties of the chamber as well forces that are external to heart, principally resulting from pericardial and right heart loads. Intrinsic factors can be divided into passive active components. Passive elements include myocardial viscoelasticity, caused structural proteins within sarcomere, extra-cellular matrix proteins, coronary vascular turgor, geometric such wall thickness, cavity shape, filling deformation. Active components stiffness related calcium handling neurohumoral activation. This manifest delayed isovolumic relaxation influences early portion LV-DPVR, or altered “tone” which overall distensibility. Among these factors, dominant determinants LV-DPVR appear structural, because generally unaltered acute pharmacological physiological manipulations. External on primarily direct ventricular interaction constraining pericardium. These loads more easily interventions likely underlie many reported upward downward shifts in various (e.g., vasodilators, channel blockers, exercise, ischemia). contribute a substantial percent (≈35%) resting pressures humans, thereby play an important role determining net dependence cardiac output pressure. In this chapter, we review focus relative influence extrinsic factors.