idiopathic hypereosinophilic syndrome ( he s ) is a condition of unknown origin characterized by clinical manifestations attributable to eosinophilia and eosinophilic infiltration of tissues .
cardiac involvement is rare and threatening accounting for 33% to 43% of death in he s .
management of pregnant patients with he s is challenging and rarely been reported , particularly in the setting of heart failure .
a 29-year - old woman returning from saint martin island presented in april 2013 with dyspnea and chest pain , which were then diagnosed as clinically suspected eosinophils - associated myocarditis because of pulmonary edema , elevated troponin , and high eosinophils blood count .
she received 3 pulses of steroids and was also treated with 2 doses of ivermectine as strongyloides serology was positive . in july 2013 , troponin dosage , eosinophils blood count , echocardiography , and cardiac magnetic resonance imaging ( mri ) were normal . in december 2013 , when she was pregnant with 18 weeks of amenorrhea ( wa ) , she was admitted to the intensive cardiology unit department for respiratory distress .
blood tests showed elevated ultrasensitive troponin : 139  ng / ml ( n  <  0.14 ) , nt - probnp : 3350  ng / l , and markedly increased circulating eosinophils at 4.75  10/l . renal and liver tests were normal .
a transthoracic echocardiogram revealed hyperkinetic left ventricular with subtotal thrombotic occlusion of left ventricle ( lv ) ( figure 1c and e ) .
cardiac mri revealed diffuse lv endomyocardial fibrosis with circumferential intraventricular adherent lv thrombus ( figure 1a ) .
no extra - cardiac involvement ( i.e. , neurological , pulmonary , cutaneous , or gastrointestinal ) was detected .
screening for all etiology of secondary or clonal eosinophilia was negative including extended lymphoid phenotyping , janus kinase 2 mutation ( jak2 ) , and factor interacting with papola and cpsf1 ( fip1l1)-type platelet - derived growth factor receptor ( pdgfra ) transcript fusion testing .
( a ) four - chamber view during cine acquisition after gadolinium injection shows subendocardial enhancement of the left ventricle ( lv ) with a large adherent thrombus inside the ventricular cavity .
( d and f ) echocardiogram findings 6 month after delivery showing complete disappearance of lv thrombus and normal lv ejection fraction .
symptomatic treatment included diuretics , low - dose -blockers , and curative anticoagulation with enoxaparin .
three intravenous pulses of 1  g methylprednisolone were administrated followed by 1  mg / kg / d of oral prednisone
. she quickly improved , keeping a class iii new york heart association ( nyha ) dyspnea . despite persistent severe postcapillary pulmonary hypertension
one month later , echocardiography was stable and eosinophils were still at 1.0  g /
azathioprine was introduced ( 2  mg / kg / d ) and steroids were progressively tapered down .
the newborn 's weight was 1900  g ( between 10th and 25th percentile ) , and birth blood ph and lactate were 7.26 and 3 
under azathioprine , 6 months after delivery , she was asymptomatic , and eosinophils blood count as well as echocardiography and cardiac mri had normalized ( figure 1 ) .
here we described a case of severe eosinophilic endomyocardial fibrosis occurring during pregnancy . under treatment with steroids and azathioprine , despite severe pulmonary hypertension , pregnancy had a favorable outcome .
acquired eosinophilia is classified as secondary ( parasitic , drug - induced , vasculitis ,  ) , clonal ( myeloid or lymphoid malignancies ,  ) , or idiopathic .
after exclusion of secondary causes of eosinophilia , a stepwise diagnostic algorithm should include peripheral blood screening for fip1l1pdgfra transcript fusion , bone marrow biopsy , jak2 mutation testing , peripheral blood lymphocytes phenotyping , and t - cell receptor gene rearrangement studies in order to discard clonal causes of eosinophilia .
the diagnostic of he s can be advocated in case of negativity of all the test cited above .
cardiac involvement of he s is rare and life - threatening , accounting for 33% to 43% of deaths , with a frequency reported from 5% to 72% .
treatment of chronic acquired eosinophilia strongly depends on whatever the cause of eosinophilia . in clonal
he s , corticosteroids remain the first - line treatment and corticosteroid - sparing agents nowadays mainly rely on hydroxyurea , interferon- , or cyclosporine . despite a promising preliminary study , mepolizumab and other anti - interleukin-5 antibodies
no specific drugs have been advocated in cardiac involvement of he s except for heart failure treatment and anticoagulation therapy because of the high frequency of intracardiac thrombus .
the use of azathioprine as a corticosteroid - sparing agent for he s has been only anecdotally reported without clear information about its efficacy .
only 3 cases of pregnancy during he s have been reported , all with favorable outcomes .
two patients were treated with steroids ( maintenance doses between 20 and 25  mg / d ) and the last one was left untreated .
one of those patients had a cardiac involvement consisting in right and lv thrombus but without cardiac failure .
the persistence of pulmonary hypertension and elevated circulating eosinophils counts led us to introduce a corticosteroid - sparing agent , namely , azathioprine , because of the safety profile during pregnancy .
six months after delivery , echocardiography and cardiac mri confirmed full resolution of interventricular thrombus with regression of endomyocardial fibrosis . in conclusion , even in a severe cardiac involvement of he s , pregnancy can successfully be conducted using steroids and azathioprine .
this study has been approved by the ethics committee : comit de protection des personnes ( cpp )  ile - de - france vi ,
the authors would like to thank professor david grant for his help in editing the manuscript .
 abstractidiopathic hypereosinophilic syndrome ( he s ) is a condition of unknown origin characterized by clinical manifestations attributable to eosinophilia and eosinophilic infiltration of tissues . 
 cardiac involvement is rare and threatening accounting for 33% to 43% of death in he s . 
 management of pregnant patients with he s is challenging and have rarely been reported , particularly in the setting of heart failure.we here report on the case of a 29-year - old woman with he s who developed severe endomyocardial fibrosis with heart failure during pregnancy . 
 outcome was favorable under treatment with prednisone and azathioprine.this case illustrates a favorable outcome of endomyocardial fibrosis during pregnancy . 
INTRODUCTION
CASE REPORT
DISCUSSION
ACKNOWLEDGMENTS