Table 2.1. Clinical clues for amyloidosis diagnosis.

History and physical examination

HFpEF, particularly in elderly men (over 65)

Intolerance to ACEI/ARB/ARNI and/or beta-blockers

Bilateral carpal tunnel syndrome

Spinal canal stenosis

Rupture of the biceps tendon

Unexplained peripheral neuropathy, particularly when associated with autonomic dysfunction

Periorbital ecchymosis

Macroglossia

Clues from Imaging Examinations and Laboratory Tests

Grade 2-3 myocardial uptake in Tc-99m pyrophosphate scintigraphy

Infiltrative phenotype on echocardiogram, with biventricular hypertrophy, pericardial effusion, valve thickening, and interatrial septum thickening

Longitudinal strain rate reduction that spares the apical region (apical sparing)

Restrictive abnormality of ventricular filling with right ventricular wall thickening

Cardiac magnetic resonance imaging showing late gadolinium enhancement with diffuse subendocardial or transmural pattern, increased extracellular volume

Proteinuria

Combined Clues

Heart failure with unexplained LV wall thickening and a nondilated ventricular cavity (intraventricular septum larger than 12 mm)

Concentric left ventricular hypertrophy with reduced or non-increased QRS amplitude proportional to degree of LV wall thickening

Reduced longitudinal left ventricular systolic function despite normal LVEF

Aortic stenosis with right ventricular wall thickening, particularly in paradoxical low-flow, low-gradient cases

ACEI: angiotensin-converting enzyme II inhibitors; ARB: angiotensin II receptor blockers; ARNI: angiotensin II receptor-neprilysin inhibitors; HFpEF: heart failure with preserved ejection fraction; LV: left ventricular; LVEF: left ventricular ejection fraction.