Cardiac amyloidosis is a significant source of morbidity among patients with systemic amyloidosis, and is the most common cause of restrictive cardiomyopathy outside the tropics.
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).
MRI is the modality of choice for evaluating cardiac amyloidosis. Features include:
- diffuse subendocardial heterogeneous pattern of increased signal on delayed contrast enhanced inversion recovery T1-weighted images (characteristic feature)
- diffuse left ventricular wall thickening (usually multiple chambers are involved)
- 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
Cardiac amyloidosis needs to be distinguished from other forms of restrictive cardiomyopathy, including: