Colour Doppler imaging in the evaluation of cardiomyopathy.

Colour Doppler imaging (CDI) is a recent method of evaluation of cardiomyop athy based on intra-myocardial abnormalities. CDI provides quantitative assessment of myocardial wall motion both circumf erential by studying the movements of the myocardium and longitudinal by st udying the movements of the mitral annulus. The harmonious decrease in velo city between the endocardium and epicardium disappears in pathological cond itions, showing disorganisation of wall motion within the myocardium. The d ecrease in the early diastolic transmural velocity gradient in patients wit h cardiomyopathy indicates diastolic dysfunction independant of the left ve ntricular systolic function. In addition, CDI is more sensitive than conventional Doppler echocardiograp hy with grey scale because it enables earlier detection of changes induced by low-dose dobutamine, allowing distinction between trained athletes and p atients with hypertrophic cardiomyopathy. The velocities of the mitral annu lus help to prevent errors of interpretation of mitral blood flow as they a re relatively independant on the left ventricular preload.