From the Guidelines
To diagnose eosinophilic endomyocardial fibrosis (EMF), a systematic approach combining clinical evaluation, laboratory tests, imaging studies, and ultimately endomyocardial biopsy is necessary. Begin with a thorough history and physical examination, looking for symptoms of heart failure, history of parasitic infections, or hypereosinophilic conditions. Order a complete blood count to check for peripheral eosinophilia (>1,500 eosinophils/μL), though normal counts don't rule out EMF as the condition may be in a later fibrotic stage 1. Perform an ECG to detect arrhythmias, conduction abnormalities, or low voltage. Echocardiography is essential and may show ventricular apical obliteration, restrictive filling pattern, atrial enlargement, and endocardial thickening. Advanced imaging with cardiac MRI provides better tissue characterization, showing late gadolinium enhancement of the endocardium. For definitive diagnosis, endomyocardial biopsy is the gold standard, revealing eosinophilic infiltration in early stages or fibrosis with minimal inflammation in later stages.
Some key points to consider in the diagnosis of EMF include:
- The importance of clinical presentation, including symptoms of heart failure and history of parasitic infections or hypereosinophilic conditions
- The use of laboratory tests, such as complete blood count and troponin levels, to assess for eosinophilia and myocardial damage
- The role of imaging studies, including ECG, echocardiography, and cardiac MRI, in characterizing the extent of cardiac involvement
- The need for endomyocardial biopsy in certain cases to confirm the diagnosis and guide treatment decisions, as recommended by the American Heart Association 1 and supported by guidelines for the evaluation of cardiomyopathy 1.
Additional tests should include troponin levels to assess myocardial damage, BNP/NT-proBNP for heart failure severity, and investigations for underlying causes such as parasitic infections, allergic disorders, or hematologic malignancies, as suggested by recent guidelines for the evaluation of myeloid/lymphoid neoplasms with eosinophilia and TK fusion genes 1. The diagnosis is based on the combination of clinical presentation, evidence of eosinophilia (current or past), characteristic imaging findings, and histopathological confirmation when possible.
From the Research
Diagnostic Approach
To diagnose eosinophilic (EOS) endomyocardial fibrosis in a suspected patient, the following steps can be taken:
- Laboratory tests to check for peripheral eosinophilia, which is often present in patients with hypereosinophilic syndrome 2, 3
- Cardiac magnetic resonance imaging (CMR) to reveal endomyocardial fibrosis and resulting valvular regurgitation 2, 4
- Doppler ultrasound to show restrictive heart failure 2
- Echocardiography to detect cardiac involvement, although it may not always be accurate 3, 5
- Endomyocardial biopsy for definitive evidence of eosinophilic myocarditis, although it may not be necessary in all cases 3, 6, 5
- Positron emission tomography combined with CT (PET-CT) as an additional imaging method 3
Imaging Techniques
Different imaging techniques can be used to diagnose EOS endomyocardial fibrosis, including:
- Cardiac magnetic resonance imaging (CMR) to demonstrate thrombus, endomyocardial fibrosis, and inflammation 4
- Echocardiography to detect cardiac involvement, although it may not always be accurate 5
- Positron emission tomography combined with CT (PET-CT) as an additional imaging method 3
- Contrast-enhanced CMR to show a three-layered appearance consisting of normal myocardium, thickened fibrotic endocardium with inflammatory exudate, and overlying thrombus 4
Biopsy and Treatment
- Endomyocardial biopsy may be indicated for definitive evidence of eosinophilic myocarditis, although it may not be necessary in all cases 3, 6, 5
- Treatment of hypereosinophilic syndrome with cardiac involvement typically involves symptomatic medical therapies, antihypereosinophilic therapy, and possibly surgical treatment 2, 3