Diagnostic tests includes serum and urine electrophoresis, laboratory testing for the determination of elevated levels of troponin and BNP, and ECGs showing low QRS voltages. Familial (ATTRm-CM)
This type is caused by mutations of proteins involved in amyloid formation, including transthyretin (TTR), fibrinogen, apolipoprotein A1, or apolipoprotein A2. Due to the multiple number of potential genetic causes the incidence of this form is variable. The vast majority of familial cardiac amyloidosis still present after the age of 60. A common mutation is the TTR gene mutation Val122Ile. It is estimated that 3.5–4% of African Americans in The United States have the Val 122lle mutation. This type of amyloidosis can be identified by genetic testing for protein mutation. For the diagnosis of familial cardiac amyloidosis to be made a biopsy with histological evaluation must be obtained. In this histological evaluation special stains are utilized to visualize the amyloid deposits. One such stain is Congo Red, which binds specifically to the amyloid deposit and can be characterized by various lighting methods. Under polarized light, the amyloid deposits while show pathognomonic apple green birefringence, and under plain light the deposits will appear a light salmon pink color. Familial amyloidosis symptoms are centered around neuropathological and cardiac problems. Cardiac manifestations of the TTR mutation present more often in The United States. Wild-type (ATTRwt-CM)
This type is considered the wild-type mutation which leads to the development of TTR deposits. It usually affects males over 70 years with the manifestation of carpal tunnel syndrome.
Cardiac amyloidosis produces specific alterations to the functionality of the heart. Echocardiography can be utilized to detect this specific pattern (relative preservation of the apical myocardium with decreased longitudinal strain in the mid and basal sections), which is 90–95% sensitive and 80–85% specific for cardiac amyloidosis. Echocardiography can be used to help physicians with diagnosis, however, it can only be used for the suggestion of the disease, not the confirmation, unless it is late stage amyloidosis. ECG/EKG
ECGs of patients with cardiac amyloidosis usually show a low voltage in the limb leads, with an unusual extreme right axis. There is usually a normal P-wave, however, it can be slightly prolonged. For patients with light-chain amyloidosis, the QRS complex pattern is skewed, with poor R-waves of the chest leads.Holter ECGs can be used to identify asymptomatic arrhythmias.EKG changes may be present, showing low voltage and conduction abnormalities like atrioventricular block or sinus node dysfunction. Laboratory Tests
Laboratory tests including urea and creatinine levels, liver enzymes, glucose, thyroid function, full blood count, and clotting tests. The analysis of serum and urine for presence of monoclonal immunoglobulin is also done through immunofixation for detection of the monoclonal band. Presence of the monoclonal band would be consistent with light chain amyloidosis. For light chain amyloidosis, serum immunoglobulin free light chain assay can be used for diagnosis and following of the amyloidosis. In light-chain amyloidosis, a low paraprotein level can be present. Cardiac biomarkers
There are two main cardiac biomarkers used in the assessment of cardiac amyloidosis, troponin and N-terminal proBNP.