isolated double - orifice mitral valve ( domv ) is an extremely rare congenital anomaly whose exact incidence has not been conclusively determined . interestingly
, this cardiac abnormality rarely presents as an isolated finding , preferentially associated with valvular regurgitation rather than stenosis .
the etiology of domv has been recognized in the abnormal fusion of the endocardial cushions and abnormal development of the mitral valve during the delamination process .
transthoracic echocardiography is the modality of choice for the characterization of this anomaly ; in this respect , the parasternal short - axis view allows a full morphologic characterization of the anomaly and should always be performed in the case of a meaningful clinical suspect .
we present the case of an asymptomatic patient with isolated domv who was referred for cardiac evaluation to achieve a certificate of fitness for competitive sports .
a 39-year - old asymptomatic and healthy man was referred to our outpatients clinic for cardiac evaluation to achieve a certificate of fitness for competitive sports .
he had no previous medical history , but presented a strong family history of early coronary artery disease .
accordingly , a complete transthoracic two - dimensional echocardiography with color doppler examination was performed with a philips ie33 ultrasound machine ( philips healthcare , leiden , the netherlands ) . the echocardiographic examination in the parasternal short - axis view showed a distinctive morphology of an isolated domv [ figure 1 ] .
the two mitral orifices were located in the posteromedial and posterolateral positions and their estimated areas were 2.20 cm and 1.98 cm , respectively [ figure 2 ] .
there was a single mitral annulus with the two valvular orifices separated by a central fibrous bridge [ figure 1 ] .
the echocardiographic examination seemed to show separated subvalvular structures for each of the two orifices [ figure 3 ] .
a normal function of both the anterior and posterior leaflets of each orifice was present without evidence of either systolic mitral regurgitation jets or diastolic turbulence [ figure 4 ] .
moreover , the two peak and the mean transmitral gradients were normal . similarly , a normally functioning mitral valve ( i.e. without stenosis or insufficiency ) was evident also in the four - chamber view .
parasternal short - axis view at the level of the mitral valve in diastole showing the bridge of tissue dividing the mitral valve into two orifices parasternal short - axis view at the level of the mitral valve in diastole showing the areas of the orifices of the double - orifice mitral valve apical four - chamber view seems to show the two separate subvalvular structures of the double - orifice mitral valve apical four - chamber view with color doppler demonstrating the absence of mitral regurgitation the resting echocardiographic examination excluded the presence of any sign of either congenital or acquired morphological cardiac abnormalities . to definitively exclude the presence of any other cardiac or vascular anomaly , a cardiac magnetic resonance imaging evaluation was performed , which confirmed the findings of two - dimensional echocardiography as it showed domv and each of the two orifices with its own chordal apparatus [ figures 57 ] .
the patient is now followed up on a yearly basis for the early recognition of any valvular alteration .
cardiac magnetic resonance imaging demonstrating normal left ventricular volumes , apex hypertrabeculation , and absence of atrioventricular / ventricular septal defects cardiac magnetic resonance imaging demonstrating the two orifices of the double - orifice mitral valve in the absence of other cardiac abnormalities cardiac magnetic resonance imaging demonstrating the two orifices of the double - orifice mitral valve in the absence of other cardiac abnormalities
this anomaly is characterized by the presence of a single mitral annulus with two orifices , each having independent subvalvular apparatus and papillary muscles .
domv is an extremely rare condition , usually associated with other congenital heart anomalies ( above all , atrioventricular septal defect , coarctation of aorta , interrupted aortic arch , patent ductus arteriosus , and ventricular septal defect ) .
it generally presents with symptoms related to mitral regurgitation or stenosis , but it can also present as an incidental finding .
three specific types of domv can be described at two - dimensional echocardiography : ( 1 ) complete bridge type ( about 15% of domvs ) , in which both openings are visible from the leaflet edge and both orifices appear circular ( equal or unequal in size ) with normal subvalvular apparatus and papillary muscles ; ( 2 ) incomplete bridge type , in which the connection is seen only at the leaflet edge ; and ( 3 ) hole type ( the most frequent ) characterized by a small accessory orifice situated at either the posteromedial or anterolateral commissure and identifiable only at the mid - leaflet level . accordingly , our patient presented the rarest form of the anomaly , as represented by the complete bridge type domv .
transesophageal echocardiography ( tee ) defines the anatomy of mitral valve better than transthoracic echocardiography and may help to differentiate domv from other conditions such as lesions of valvular leaflets provoked by endocarditis .
however , despite these theoretical advantages , tee was not performed in the diagnostic work - up of the patient because of its invasiveness .
on the other hand , once domv is nearly assured by two - dimensional echocardiography , cardiac magnetic resonance imaging evaluation becomes a mandatory step to confirm the clinical suspicion , and above all , to exclude any concurrent cardiac and vascular abnormalities .
moreover , three - dimensional echocardiography is generally useful to add anatomical details to that obtained by two - dimensional echocardiography .
however , it should be performed only in case of uncertain findings at the two - dimensional echocardiography , which is considered the screening test for domv .
the management of domv is related to the type and severity of mitral valve dysfunction .
asymptomatic domv usually requires no active intervention ; in case of severe mitral regurgitation , stenosis , or associated cardiac anomalies , surgical repair is needed . in all cases of domv , a long - term follow - up is required for the early detection of complications .
thus , domv is a very rare anomaly which is usually detected by transthoracic two - dimensional echocardiographic examination in short - axis parasternal views .
nevertheless , it can be rarely diagnosed in asymptomatic middle - aged and elderly patients . in any case , the presence of other coexistent cardiovascular abnormalities should be excluded .
 double - orifice mitral valve ( domv ) is a very rare congenital anomaly that usually presents as mitral regurgitation . 
 we present the case of a 39-year - old asymptomatic , healthy man with no previous medical history who was affected by isolated complete bridge type domv , incidentally detected by two - dimensional echocardiographic examination in the parasternal short - axis view . 
 the mitral valve of the patient was normally functioning without any other coexistent cardiac abnormalities . 
 isolated domv was also confirmed by cardiac magnetic resonance imaging . 
 the patient is now followed up to detect possible complications . 
INTRODUCTION
CASE REPORT
DISCUSSION
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