Differential Diagnosis in ATTR-CM: 99mTc-PYP Scintigraphy and Diagnostic Workup

Key Takeaways

• In ATTR-CM, the diagnostic challenge is knowing when nonspecific findings justify moving from routine cardiomyopathy evaluation to structured amyloidosis workup.
• Suspicion usually depends on a cluster of cardiac and extracardiac clues, since no single feature is diagnostic and coexisting disease can obscure the pattern.
• Excluding AL amyloidosis is central because it can mimic ATTR-CM, and monoclonal protein testing helps narrow the differential without confirming ATTR-CM by itself.
• Echocardiography, cardiac MRI, and 99mTc-PYP scintigraphy refine probability, but each requires clinical context and careful interpretation against common mimics.
• NT-proBNP and troponin reflect myocardial stress or injury rather than amyloid type, while genetic testing helps identify hereditary ATTR-CM but does not exclude wild-type disease if negative.