Electron microscopy in patients with clinically suspected of cardiac amyloidosis who underwent endomyocardial biopsy and negative Congo red staining

摘要

In the clinical practice of patients with diastolic heart failure and concentric left ventricular hypertrophy, cardiac amyloidosis is an important differential diagnosis. The traditional golden standard for diagnosing cardiac amyloidosis is endomyocardial biopsy (EMB) which showing positive Congo red staining with demonstration of apple-green birefringence under polarized light microscope. However, there were still a small number of patients who clinically suspected of cardiac amyloidosis, but the Congo red staining was negative. Previous studies showed that electron microscopy could be used as the diagnostic tool for amyloidosis which showing the presence of rigid, non-branching fibrils of 7 to 10 nm in diameter.