Background: Despite significant advances in non-invasive imaging, endomyocardial biopsy (EMB) remains the gold standard for the definitive diagnosis of various heart diseases, including myocarditis, storage diseases, and cardiomyopathies. In the age of precision medicine, EMB provides unique histopathological, immunohistochemical, and molecular biological information that enables individualized therapy. In this study, we present comprehensive EMB results from over 8,000 patients with unexplained heart failure and demonstrate the diagnostic and therapeutic benefits of EMB.
Methods: We retrospectively analyzed 8,085 EMBs with suspected unclear heart failure. Clinical data, suspected diagnoses, and EMB findings, including histology, immunohistochemistry, virology, and molecular biology, were systematically reviewed and correlated with the referring clinical diagnosis.
Results: Cardiac storage disease was diagnosed in 616 patients (7.6%), predominantly ATTR (n=442) or AL amyloidosis (n=164). Acute myocarditis was found in 357 patients (4.4%), including 95 cases of active lymphocytic myocarditis, 148 cases of giant cell myocarditis, 95 cases of sarcoidosis, and 19 cases of eosinophilic myocarditis. A total of 3,392 patients (42%) had inflammatory cardiomyopathy, with the quality and quantity of infiltrates varying greatly. Viral genomes were detected in the myocardium of 6,072 patients (75%); therapy-relevant infections were present in 2,015 patients (25%). In the remaining 1,705 patients (21%), other cardiomyopathies were diagnosed, including DCM (n=1,252), HFpEF (n=325), HCM (n=117), and ARVD (n=11). EMB diagnostics led to specific therapy recommendations in 79% of cases; in 21% of cases, infectious and inflammatory causes could be ruled out and standard heart failure therapy initiated.
Conclusions: This analysis shows that comprehensive EMB diagnostics enable definitive diagnoses, provide crucial therapy-relevant information, and support the differentiation between infectious, inflammatory, and non-inflammatory cardiomyopathies. EMB therefore remains an important pillar in the diagnosis of heart diseases.
