[Cardiac amyloidosis. Invasive and noninvasive diagnosis]

Aim of this study is the analysis of clinical, morphologic and haemodynamic features of cardiac amyloidosis. Cardiac amyloidosis was demonstrated histologically in 7 of our patients: in 6 by endomyocardial biopsy during cardiac catheterization, in one at autopsy. The clinical picture was characterized in every patient by signs and symptoms of congestive heart failure. The electrocardiogram showed several non specific signs: low voltage of the QRS complexes, both in peripheral (4/7) and precordial leads (7/7 cases); marked leftward and upward deviation of the QRS axis (6/7 cases); first degree A-V block (5/7); abnormal Q waves (7/7). M-mode and two-dimensional echocardiography invariably demonstrated a typical pattern: a non dilated left ventricle with thickened and hyper-refractile walls, and usually a slight-moderate diffuse hypokinesia. Other common features were a thickening of right ventricular walls, interatrial septum, and atrioventricular and semilunar valves. Computerized analysis of the M-mode tracings disclosed a marked impairment of the indexes of both systolic and diastolic ventricular function in all patients. By correlating electrocardiographic and echocardiographic data, we found in every case a striking disproportion between the low QRS voltage and the high muscle cross-sectional area (an echocardiographic index of left ventricular mass): this pattern appears to be highly suggestive of infiltrative heart disease. Cardiac catheterization (performed in 6 cases) showed an increase of left ventricular (6/6) and right ventricular (5/6) end-diastolic pressure, with a dip plateau pattern in some cases (4/6 of the left, 2/6 in the right ventricle). The cardiac index was decreased in 3/6 cases. Left ventricular angiography confirmed the echocardiographic data of normal volumes and a slight-moderate decrease of the ejection fraction. We conclude that cardiac amyloidosis usually mimics a restrictive cardiomyopathy (severe congestive heart failure with increased ventricular filling pressures, in the absence of severe systolic ventricular dysfunction). This disease can be suspected clinically by the correlation of the clinical, electrocardiographic and echocardiographic data. The final diagnosis requires an endomyocardial biopsy.