Concurrent Use of Tafamidis and Mavacamten for Transthyretin Cardiac Amyloidosis With Severe Outflow Tract Obstruction.

BACKGROUND

Cardiac amyloidosis (CA) and hypertrophic cardiomyopathy often manifest with overlapping clinical features, making diagnosis and management challenging.

CASE SUMMARY: We describe a 79-year-old man presenting with exertional dyspnea and presyncope who was diagnosed with transthyretin CA with left ventricular outflow tract (LVOT) obstruction and was treated with concurrent mavacamten and tafamidis.

DISCUSSION: There is substantial overlap in the clinical phenotypes of hypertrophic cardiomyopathy and CA, and the presence of hemodynamically significant LVOT does not exclude the possibility of CA as an underlying diagnosis. Endomyocardial biopsy may be required when noninvasive testing is ambiguous or in the presence of overlapping disease features.

TAKE-HOME MESSAGES: Hemodynamically significant LVOT obstruction is a rare but clinically relevant manifestation of CA that may lead to diagnostic ambiguity and difficult management decisions. Tafamidis and mavacamten can be used safely in combination to provide symptom relief and slow disease progression in obstructive transthyretin CA.