Diagnostic challenges in cardiac amyloidosis: a case report of negative initial endomyocardial biopsy.

Cardiac amyloidosis (CA) is a challenging acquired heart disease caused by the deposition of β-pleated amyloid proteins, often leading to nonspecific symptoms that complicate the diagnosis. This case report describes an 83-year-old male patient presenting with chest pain and cough, revealing significant cardiomegaly and pericardial effusion on imaging. Initial diagnostic modalities, including echocardiography and endomyocardial biopsy (EMB), have yielded inconclusive results. Despite a negative EMB result, further investigation using positron emission tomography/computed tomography ruled out cardiac sarcoidosis. A second EMB was performed to confirm the diagnosis of CA. This case underscores the importance of combining clinical symptoms with paraclinical assessments and advocating additional testing when discrepancies arise, highlighting the complexities in diagnosing CA. This case report emphasizes the necessity for clinicians to integrate clinical symptoms with diagnostic findings when assessing for cardiac amyloidosis. This illustrates the potential for false-negative biopsies and the importance of considering further testing to ensure an accurate diagnosis, ultimately enhancing diagnostic accuracy and patient management in cases of suspected cardiac amyloidosis.