A 50-year-old male presented with signs and symptoms of restrictive hea disease. A right ventricular endomyocardial biopsy revealed deposition of extracellular eosinophilic hyaline material. On transmission electron microscopy, this material is most likely to reveal the presence of
High-Yield Explanation
Amyloidosis is the major cause of restrictive cardiomyopathyCardiac amyloid is classically suspected from thickened ventricular walls with an ECG that shows low voltage.By electron microscopy, all types of amyloid consist of continuous, nonbranching fibrils with a diameter of approximately 7.5 to 10 nm. X-ray crystallography and infrared spectroscopy demonstrate a characteristic cross-b-pleated sheet conformationHarrison 19e pg: 1567