Revision 21 for 'Cardiac amyloidosis'All Revisions
Amyloidosis represents the extra-cellular deposition of insoluble fibrillar proteinaceous material in various organs and tissues in a variety of clinical settings. For a general discussion of the condition please refer to amyloidosis.
Cardiac involvement is seen with most forms of amyloidosis, although it is most common and most often clinically significant with primary amyloidosis (i.e. associated with multiple myeloma or other monoclonal gammopathies).
There are 2 main forms of amyloidosis that significantly affect the heart.
- AL amyloidosis: acquired disease
- transthyretin-related (TTR) amyloidosis: there are 2 types of TTR-related amyloidosis:
- genetic form: hereditary transthyretin-related amyloidosis (ATTR)
- non-hereditary form: senile systemic amyloidosis (SSA)
MRI is the modality of choice for evaluating cardiac amyloidosis. Features include:
- diffuse decrease in the T1 and T2 signal intensity of myocardium
- diffuse left ventricular wall thickening (usually multiple chambers are involved); can be associated with thickening of both atrial walls in which case,a thickening of > 6mm of inter-atrial septum or posterior right atrial wall is specific to amyloidosis
- biventricular diastolic dysfunction with normal systolic function and ejection fraction
- subsequently (later in the course of disease) may show systolic biventricular dysfunction with decreased ejection fraction
- restriction of diastolic filling
- disproportionate atrial enlargement
- pericardial and pleural effusions
- diffuse sub-endocardial heterogeneous increased signal on delayed contrast-enhanced inversion recovery T1-weighted images (a characteristic feature)
- transmural enhancement may be more prevalent in patients with ATTR compared to patients with AL 6
Cardiac amyloidosis needs to be distinguished from other forms of restrictive cardiomyopathy, including: