Extracardiac manifestations include:

Macroglossia
Periorbital bruising
Loss of the third and fourth heart sound
Thromboembolisms
Symmetric sensory neuropathy (such as bilateral carpal tunnel)
Postural hypotension (secondary to autonomic neuropathy)
Nephrotic syndrome (secondary to free light chain damage to the kidneys/deposition of amyloid in the kidneys)

Cause
The general cause of cardiac amyloidosis is the misfolding of a specific protein precursor depending on the amyloidosis type. Protein precursors include immunoglobulin-derived light chains and transthyretin mutations. The misfolding of the protein causes it to have insoluble beta-pleated sheets, creating an amyloid. Amyloid, the aggregation, or clumping, of proteins, is resistant to degradation by the body. Amyloids are mostly fibrils, while also containing a P component, apolipoprotein, collagen, fibronectin, and laminin. The P component, a pentameric protein, stabilizes the fibrils of the amyloid, which reduces their clearance from the body. Deposits of the amyloids can occur throughout the body, including the heart, liver, kidneys, spleen, adrenal glands, and bones. Deposits in the extracellular cardiac space can stiffen the heart, resulting in restriction of the ventricles. This restriction in ventricular motion results in a decreased ability for the heart to pump efficiently, leading to the various symptoms associated with cardiac amyloidosis. Diagnosis
Echocardiography
Echocardiography is a safe and non-invasive method that can be used to assess the structural and functional disease of the heart. Amyloidosis presents with ventricle and valvular thickening, biatrial enlargement, restrictive filling pattern, with normal to mildly reduced systolic function and decreased diastolic filling. An echo can be used to evaluate for prognosis of the disease, measuring the different strains within the heart.
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.