Transthyretin Cardiac Amyloidosis With Reduced Ejection Fraction in a 47-Year-Old Man: An Unusual Presentation.

Cardiac amyloidosis is an infiltrative cardiomyopathy caused by extracellular deposition of misfolded proteins, leading to restrictive physiology and, in advanced stages, systolic dysfunction. Although transthyretin amyloidosis most commonly affects older adults, earlier presentations should prompt consideration of hereditary disease and genetic evaluation. We report a 47-year-old man admitted with advanced heart failure manifested by anasarca and progressive dyspnea. Electrocardiography showed low-voltage QRS complexes discordant with the degree of wall thickening. Transthoracic echocardiography revealed concentric left ventricular thickening with markedly reduced left ventricular ejection fraction (35%), and speckle-tracking demonstrated a reduced global longitudinal strain with relative apical sparing. Technetium-labeled bone scintigraphy demonstrated Perugini grade 2 myocardial uptake in the absence of monoclonal gammopathy, strongly supporting transthyretin cardiac amyloidosis (ATTR-CM). Tafamidis was initiated, and genetic testing was requested; however, results were not available at the time of manuscript submission. This case highlights that ATTR-CM should be considered in patients with unexplained heart failure and increased ventricular wall thickness even at a relatively young age, and that prompt diagnosis enables timely initiation of targeted therapy and supports genetic counseling and family screening when hereditary disease is suspected.