right sided valvular involvement in infective endocarditis has been well - described , but lesions affecting eustachian valve are distinctly rare . in 1986 , edwards et al . first described the entity of eustachian valve endocarditis ( eve ) in an autopsy study of a patient with overwhelming streptococcal sepsis . in the literature only few cases have been reported so far . herein , we review the literature and describe 2 new cases in which the causative organisms were determined to be vancomycin resistant staphylococcus aureus ( vrsa ) , which is reported for the first time , and staphylococcus hominis . a 33 year old woman with a history of intravenous drug use was admitted with a history of fever , chills and cough for the last 4 days . on presentation , she was noted to have a temperature of 102.4 f ( reference range 96.8 - 100.4 f ) , an elevated pulse rate ( 110 bpm ) ( reference range 55 - 90 bpm ) , respiration rate of 26 breaths / min ( reference range 12 - 20 breaths / min ) and low blood pressure ( 90/50 mm hg ) ( reference range 100 - 139/55 - 84 mm hg ) . blood investigation showed an elevated white blood cell count ( 22,600 cells/l ) ( reference range 4000 - 11000 cells/l ) . suboptimal images by transthoracic echocardiography ( tte ) showed mobile vegetation on the tricuspid valve , along with severe tricuspid regurgitation . transesophageal echocardiography ( tee ) revealed a 6-cm , echogenic mass attached to the eustachian valve , [ figures 1 and 2 ] along with pulmonary valve and right ventricular wall . during the next 2 days , the patient 's condition was complicated by hemoptysis , renal failure and hypoxic respiratory failure requiring mechanical ventilation . transesophageal echocardiography image demonstrating a large vegetation ( 6 cm ) attached to the eustachian valve ( case 1 ) vege : vegetation , ivc : inferior vena cava . transesophageal echocardiographic image of vegetation attached to the right ventricular wall ( case 1 ) pulmonary ary : pulmonary artery . she was treated with intravenous daptomycin initially with 6 mg / kg every 24 hours , and was discharged after 4 weeks of antibiotics . a 86-year - old nursing home female with a history of dementia , severe aortic stenosis , congestive heart failure , chronic anemia secondary to gastrointestinal bleeding requiring implantable venous catheter insertion , presented with high grade temperature of 103f ( reference range 96.8 - 100.4 f ) rectally , pulse rate of 124bpm ( reference range 55 - 90 bpm ) , respiration rate of 23 breaths / min ( reference range 12 - 20 breaths / min ) and blood pressure of 128/69 mm hg ( reference range 100 - 139/55 - 84 mm hg ) . laboratory data showed an elevated white blood count 30,000 cells/l ( 86% polymorphs ) ( reference range 4000 - 11000 cells/l ) , low hemoglobin of 7.1 g / dl ( reference range 14.0 - 18.0 g / dl ) and normal platelets ( 323,000/l ) ( reference range 150,000 - 450,000/l ) physical examination revealed a thin , cachectic female with a late peaking systolic murmur at the left sternal border , a soft s2 and few scattered rhonchi all over the lungs . tte revealed moderate concentric left ventricular hypertrophy with ejection fraction of 70% , a heavily calcified aortic valve with severe aortic stenosis and moderate pulmonary hypertension ; however , no vegetations were identified . the patient received 4 weeks of vancomycin , 30 mg / kg in divided doses every 24 hours and became afebrile with second set of blood culture turning negative . a 33 year old woman with a history of intravenous drug use was admitted with a history of fever , chills and cough for the last 4 days . on presentation , she was noted to have a temperature of 102.4 f ( reference range 96.8 - 100.4 f ) , an elevated pulse rate ( 110 bpm ) ( reference range 55 - 90 bpm ) , respiration rate of 26 breaths / min ( reference range 12 - 20 breaths / min ) and low blood pressure ( 90/50 mm hg ) ( reference range 100 - 139/55 - 84 mm hg ) . blood investigation showed an elevated white blood cell count ( 22,600 cells/l ) ( reference range 4000 - 11000 cells/l ) . suboptimal images by transthoracic echocardiography ( tte ) showed mobile vegetation on the tricuspid valve , along with severe tricuspid regurgitation . transesophageal echocardiography ( tee ) revealed a 6-cm , echogenic mass attached to the eustachian valve , [ figures 1 and 2 ] along with pulmonary valve and right ventricular wall . during the next 2 days , the patient 's condition was complicated by hemoptysis , renal failure and hypoxic respiratory failure requiring mechanical ventilation . transesophageal echocardiography image demonstrating a large vegetation ( 6 cm ) attached to the eustachian valve ( case 1 ) vege : vegetation , ivc : inferior vena cava . transesophageal echocardiographic image of vegetation attached to the right ventricular wall ( case 1 ) pulmonary ary : pulmonary artery . she was treated with intravenous daptomycin initially with 6 mg / kg every 24 hours , and was discharged after 4 weeks of antibiotics . a 86-year - old nursing home female with a history of dementia , severe aortic stenosis , congestive heart failure , chronic anemia secondary to gastrointestinal bleeding requiring implantable venous catheter insertion , presented with high grade temperature of 103f ( reference range 96.8 - 100.4 f ) rectally , pulse rate of 124bpm ( reference range 55 - 90 bpm ) , respiration rate of 23 breaths / min ( reference range 12 - 20 breaths / min ) and blood pressure of 128/69 mm hg ( reference range 100 - 139/55 - 84 mm hg ) . laboratory data showed an elevated white blood count 30,000 cells/l ( 86% polymorphs ) ( reference range 4000 - 11000 cells/l ) , low hemoglobin of 7.1 g / dl ( reference range 14.0 - 18.0 g / dl ) and normal platelets ( 323,000/l ) ( reference range 150,000 - 450,000/l ) physical examination revealed a thin , cachectic female with a late peaking systolic murmur at the left sternal border , a soft s2 and few scattered rhonchi all over the lungs . tte revealed moderate concentric left ventricular hypertrophy with ejection fraction of 70% , a heavily calcified aortic valve with severe aortic stenosis and moderate pulmonary hypertension ; however , no vegetations were identified . the patient received 4 weeks of vancomycin , 30 mg / kg in divided doses every 24 hours and became afebrile with second set of blood culture turning negative . eustachian valve is an embryological remnant of the sinus venosus , directing oxygenated fetal blood from inferior vena cava across foramen ovale , and into the left atrium . in adults , it is non - functional and is considered a benign rudimentary structure . we present 2 new cases of eve with a review of literature [ table 1 ] . in the previously reported cases , the age of patients ranged from 22 years to 76 years with a median age of 44.2 years , with a male to female ratio of 5:3 . there seems to be an increasing trend in elderly population . in the present study , the incidence of eve is not well documented ; however , a retrospective review by san roman et al . reported an incidence of 3.3% in patients with right sided endocarditis . summary of reported cases of eustachian value endocarditis , their location , microbial agents involved , and prognosis a predisposing factor was present in all but three cases,[35 ] with intravenous drug use ( 40% of the cases ) being the most common . other predisposing factors were presence of indwelling catheters , insertion of pacemaker wires , a history of rheumatic heart disease , and immunologic compromise ( chronic alcoholism , human immunodeficiency virus  [ hiv ] ) status . the increasing prevalence of indwelling catheters / devices may be the reason for increasing incidence of eve in the elderly population . in the present study , a history of intravenous drug use was obtained in one case , and insertion of implantable venous catheter for repeated blood transfusions in the other case . the blood culture revealed staphylococcus aureus to be the most common pathogenic organism in 53% of the cases , which is consistent with previous reviews sawhney et al . the association of staphylococcus aureus positivity on blood cultures with intravenous drug abuse ( ivda ) and indwelling catheters was found to be in 100% of the cases . other organisms that have been reported so far include staphylococcus hominis , enterococcus cloacae , escherichia coli , proteus vulgaris , streptococcus viridans , klebsiella pneumonia   and actinomyces israeli . in our present report , this is the first case of vrsa eve reported in the literature . in the second case , staphylococcus hominis , a harmless commensal on human skin was the causative organism , likely related to the implantable venous access catheter insertion for chemotherapy ( which is reported for the first time also ) . like many other coagulase - negative staphylococci , staphylococcus hominis may occasionally cause infection in patients with compromised immune system . both cases in our series the finding was in concordance with previous studies in which the vegetations were seen more frequently on tee than tte . as the eustachian valve is situated posteriorly , the superiority of tee over tte is seen frequently . only in reports by punzo et al . and in 2 other cases reported by georgeson et al . , tte was frankly misleading , suggesting a ruptured chordae tendinae in one patient , and chiari 's network in the other . tee allows not only better visualization of the eustachian valve and chiari network , but also easily differentiates pathological masses from these normal structures . nevertheless , tte remains the first imaging investigation of choice ; and , tee should be performed if clinical picture strongly suggests endocarditis and no lesions are identified on tte . though eve was first described in a post - mortem autopsy case , eve seems to follow a benign clinical course presenting as right sided endocarditis , resolving with a 4 - 6 week course of culture sensitive antibiotics , as seen in 78% of patients described till date . few patients had a transient worsening of symptoms requiring intubation , open heart surgery with removal of eustachian valve . it should be strongly considered when a patient has the clinical syndrome of right - sided endocarditis , but no vegetations are identified on tte . we found the incidence of eve to be highest in young intra - venous drug users , and staphylococcus aureus to be the most common microbial agent . however , over the past 6 years eve has been seen more frequently in the elderly population with culture positivity for diverse microbial agents . although eve is rare , it may be unwise to rule out this diagnosis based solely on tte , especially in the setting of persistent bacteremia or pulmonary emboli .
eustachian valve endocarditis ( eve ) is a distinctly rare and underdiagnosed entity . 
 we report 2 new cases caused by vancomycin resistant staphylococcus aureus and staphylococcus hominis diagnosed on transesophageal echocardiography ( tee ) . although , 63% of eustachian valve endocarditis is caused by staphylococcus aureus , we report the first case of vancomycin resistant staphylococcus aureus and first case related to implantable venous access systems . 
 eve is now seen more commonly in elderly population with diverse microbial cultures and antibiotic sensitivities . 
 tte is the first modality for investigation of eve , however a negative tte does not preclude the diagnosis , as only 88% of cases were diagnosed on tee .