Loeffler Endocarditis Workup

Updated: Feb 06, 2020
  • Author: Sohail A Hassan, MD; Chief Editor: Richard A Lange, MD, MBA  more...
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Approach Considerations

Echocardiography, Doppler studies using echocardiogram, cardiac catheterization, computed tomography (CT) scanning or magnetic resonance imaging (MRI) of the chest, electrocardiography (ECG), and endomyocardial biopsy may all be useful in diagnosis, as for cardiomyopathy of any cause. [31]


Laboratory Studies

Complete blood cell (CBC) counts should be performed to look for the presence of eosinophils. Peripheral eosinophilia should not be considered mandatory for the diagnosis of Loeffler endocarditis, as described by Priglinger et al. [12]

Cytogenetics, fluorescent in situ hybridization (FISH), and molecular analysis show the presence of the FIP1L1-PDGFRA fusion gene as demonstrated by Cools et al and Rotoli et al. [18, 20]



The echocardiographic hallmark of Loeffler endocarditis includes a restrictive pattern of filling with relatively preserved left ventricular systolic function, as reported by Parillo et al. [32, 33]

Localized thickening of the basal posterior wall of the left ventricular free wall and restricted motion of the posterior leaflet of the mitral valve are seen, as reported by Spyrou et al and Child et al. [34, 35]

Apical thrombus in the left ventricle also has been reported. Also, presentation with restriction of the mitral apparatus with a large thrombus has been reported. [29]

Regurgitant AV valve lesions are often present.

Recurrent thrombosis of the prosthetic mitral valve in the setting of rising eosinophilia has been reported. [36, 37]

Three echocardiographic features of amyloidosis, another cause of restrictive cardiomyopathy, include thickened interatrial septum; thickening of the cardiac valves; and granular, sparkling texture of the myocardium. All may be present in amyloidosis but not in Loeffler endocarditis.

Echocardiographic Doppler findings are of restrictive cardiomyopathy, including decreased right ventricular and left ventricular velocities with inspiration and inspiratory augmentation of hepatic-vein diastolic flow reversal.


Cardiac Catherization

Cardiac catheterization reveals markedly elevated ventricular filling pressures and the presence of mitral or tricuspid regurgitation.

On left ventriculography, a characteristic feature is preserved left ventricular systolic function with obliteration of the left ventricular apex, as reported by Weller and associates. [25]

The hemodynamic picture on cardiac pressure tracings reveals a restrictive picture due to dense endocardial scarring and a reduction in left ventricular cavity caused by an organized thrombus, as reported by Weller et al and Parillo et al. [25, 32] The hemodynamic picture may include elevation of left ventricular end diastolic pressure, often greater than 5 mm Hg over right ventricular end diastolic pressure; however the pressures may be identical at times.


Cardiac Magnetic Resonance Imaging

Cardiac MRI findings of endomyocardial fibrosis include right ventricular diastolic dysfunction, mild systolic dysfunction, and extensive subendocardial delayed contrast enhancement. [38]

Hybrid positron emission tomography/MRI (PET-MRI) has the potential to be useful in confirming the diagnosis of Loeffler endocarditis and the progression of inflammatory activity in affected patients. [39]



ECG shows nonspecific ST-segment and T-wave abnormalities as reported by Spyrou et al and Arnold et al. [34, 40]

Arrhythmia, especially atrial fibrillation, and conduction system defects, particularly right-bundle branch block, may be present, as reported by Fawzy et al. [41]

Nonspecific findings may include pseudo infarction patterns of left-axis deviation.



Percutaneous endomyocardial biopsy often confirms diagnosis. As endomyocardial involvement may be patchy, a false-negative biopsy result also is possible, as reported by Felice and colleagues. [42]


Histologic Findings

Histologic specimens of the myocardial biopsy reveal thick and deep layers of loosely arranged collagen tissue, which, although localized primarily to the endocardium, may have strands extending into the underlying myocardium. Although peripheral eosinophilia is characteristic of Loeffler endocarditis, eosinophilic infiltration of the tissues and arteries is less common, possibly because of the infrequency of biopsy.