Optimal screening of heart failure patients: tissue Doppler imaging or plasma NTpro BNP measurement?

Excerpt

Early detection and treatment of left ventricular dysfunction is of major importance. Ideally, therapy will be performed before irreversible cardiac damage has occurred. To do this, a sensitive evaluation of cardiac function and cardiac mechanics is required. However, cardiac function is difficult to define and the assessment of function in a clinical context often uses a surrogate for function. One can divide cardiac function in intrinsic myocyte function or contractility and ventricular pump function [1]. Force development results in the generation of sufficient pressure to open the cardiac valves. On the other hand results deformation of the ventricles in the ejection of blood. The interaction between force development and deformation are determined by ventricular wall properties such as tissue composition, fibre structure and global geometry on one hand and the interaction between the heart and the loading conditions on the other hand. The most reliable parameter to measure intrinsic myocardial contractility is by calculation of the end-systolic pressure-volume relationship (E-max) [2]. This is an invasive technique and not always applicable in clinical practice. Therefore in clinical practice, surrogate measurements of force development and volume ejection are used with non-invasive techniques, like echocardiography, magnetic resonance imaging or computed tomography. The evaluation of ejection fraction with these techniques, however has severe shortcomings because the assessment of intrinsic cardiac function using ejection fraction depends on geometric assumptions. Volume based indices are load dependent and these parameters only assess global function. To overcome these problems, new echocardiographic techniques, like tissue Doppler imaging have been developed, which measure myocardial motion and deformation. …