The role of echocardiography in the non-invasive diagnosis of cardiac amyloidosis

The diagnosis of cardiac amyloidosis (CA) is usually performed by endomyocardial biopsy; however, possible sampling errors and procedural risks such as cardiac tamponade, malignant arrhythmias and bleeding risk, limit its use. Therefore, a non-invasive diagnostic method appears to be necessary.

Echocardiography plays an important role in this need. Conventional two-dimensional echocardiography appears able to detect some specific and distinguishing signs of cardiac amyloid infiltration.

Of these, thickened right and left ventricular (LV) myocardium, normal or small LV cavity size in contrast to enlarged biatrial cavities, diffuse hyper-refractile ‘granular sparkling’ appearance and ‘mismatch’ ECG/ECHO are the most specific findings. The magnitude of cyclic variation recorded with integrated backscatter reflects structural changes in the myocardium. In patients with CA, this magnitude is reduced because myocardial amyloid infiltration is characterized by a reduction of number of “contractile” fibers. Other informations concerning LV dysfunction CA-related can be obtained by Tei index. Finally, new echocardiographic imaging modalities, such as tissue Doppler, Doppler-based strain, speckle tracking imaging and three-dimensional echocardiography, can provide some findings regarding the preclinical stages of LV dysfunction when other echocardiographic measurements are showing normal; however, these are unable to provide a non-invasive diagnosis of cardiac amyloidosis.