Clinical value of echocardiography in patients with 'heart failure'.
The clinical syndrome of 'heart failure' can be caused by a variety of haemodynamic disturbances, which can be analysed by echocardiography. Occasionally, occult valve disease may be present. The commonest cause is left ventricular disease. Two-dimensional echocardiography allows cavity size and shape to be studied, and when combined with colour amplitude processing, regional abnormalities of acoustic properties of the myocardium detected, and shown to have clinical significance. Digitization of combined M-mode and 2D records allows endocardial position and wall dynamics to be studied, at a repetition rate of 1000/s in known positions in the ventricle. Abnormal systolic function can be analysed in great detail, and the effects of a dilated cavity distinguished from those incoordinate wall motion. Reduced contraction velocity can also be identified, but this is rare as an isolated abnormality. A series of diastolic abnormalities can also be detected, including incoordinate relaxation in coronary artery disease, and prolonged isovolumic relaxation and reduced rate of diastolic wall motion in left ventricular hypertrophy. When simultaneous high fidelity pressure is available, myocardial power, work, and stress-strain relations can be documented. Thus 'heart failure' is not a discrete entity, and there is no single type of clinical left ventricular disease corresponding to 'depressed contractility' to be detected by echocardiography in its early or late stages. Much more valuable, however, is the use of the technique to record a series of separable abnormalities of ventricle function, to quantify them in individual patients, and to follow the effects of treatment.
D006332:Cardiomegaly / Q000175:diagnosis; D004452:Echocardiography; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D009200:Myocardial Contraction