Echocardiography is an invaluable tool for the routine evaluation of patients with congestive heart failure. A number of Doppler modalities are now available. In this comment, the haemodynamic determinants and the clinical application of the more recent indices of left ventricular relaxation, namely tissue Doppler imaging of the mitral annulus and the flow propagation velocity by colour M-mode, and the importance of the study by Graham et al. in this issue of Clinical Science are discussed.
