An integrated framework for the assessment of cardiac function - Description and illustrated applications

Abstract

Assessing myocardial function is a difficult task in clinical practice. Routinely, (systolic) cardiac function is mostly quantified based on ejection fraction, a measure of the volume fraction of the left ventricle being ejected with each cardiac cycle. However, this approach has a lot of limitations since normal ejection fraction can occur while there are clearly functional abnormalities, while a reduced value does not say anything about what is wrong with the heart muscle. Recently, echocardiographic strain (-rate) imaging has been introduced, enabling the regional quantification of myocardial deformation. However, local deformation is also influenced by a number of factors and therefore does not necessarily represent local contractile force development. In this paper, we present an integrated framework, describing intrinsic cardiac function in its relationship with the boundary conditions. To illustrate how this framework can be used to study and understand cardiac function, two applications are discussed (regional ischemia and left bundle branch block). These applications are illustrated with simulations of regional deformation profiles.