[Contribution of echocardiography to the diagnosis of patients with chronic heart failure]

The echocardiographic examination is generally performed in patients with heart failure and it often gives a significant contribution to the differential diagnosis. Firstly, the evaluation of left ventricular pump function by measuring the ejection fraction (EF) can distinguish patients with heart failure into two different groups, with depressed or preserved EF. The most frequent causes of heart failure and depressed EF are coronary artery disease, idiopathic dilated cardiomyopathy (DCM) and hypertensive heart disease. Although the echocardiographic features of coronary artery disease versus idiopathic DCM may be similar, the demonstration of inducible ischemia at dobutamine echocardiographic test suggests the presence of significant coronary artery disease and may be useful in the selection of cases for coronary arteriography. The association of left ventricular hypertrophy, hypokinesis and, sometimes, significant dilation is compatible with hypertensive heart disease or end-stage hypertrophic cardiomyopathy. No useful echocardiographic findings can identify the patients with genetic DCM or affected by myocarditis from other cases with idiopathic DCM. Some advanced cases of right ventricular dysplasia/cardiomyopathy may show a biventricular involvement and mimic DCM; these patients are usually characterized at echo by predominant right ventricular dilation and multiple a-dyskinetic bulges in the absence of pulmonary hypertension. Very difficult to manage are the patients with significant left ventricular dysfunction and severe valvular heart disease (such as aortic stenosis or mitral regurgitation). According to the literature, the left ventricular systolic function is relatively preserved (EF > 40%) in 30-40% of patients with heart failure. In these cases a diastolic dysfunction may be hypothesized. Echo-Doppler evaluation can be helpful in the recognition of signs of increased left ventricular stiffness ("restrictive filling pattern") and of increased filling pressures. In the differential diagnosis one must first consider the most frequent heart disorders that may present with this clinical syndrome, coronary artery disease and hypertensive heart disease. Furthermore, other less common diseases characterized by heart failure due to predominant diastolic dysfunction are the following: hypertrophic and restrictive cardiomyopathies, infiltrative heart diseases, such as amyloidosis, and constrictive pericarditis. Restrictive cardiomyopathy is characterized by heart failure and preserved left ventricular EF in the absence of significant ventricular dilation and hypertrophy; typical, although not pathognomonic, echocardiographic features are atrial enlargement ad restrictive filling pattern. In distinguishing constrictive pericarditis from restrictive cardiomyopathy useful Doppler signs are the wide respiratory variability in flow velocities at mitral and tricuspid levels, due to increased ventricular interdependence caused by the presence of an abnormally rigid pericardium.