CASE PRESENTATION
A 15-year-old girl was referred to our hospital with a history of chest
pain, shortness of breath, and presyncope. She had been suffering from
chest pain since the age of 12 and had a history of frequent dizziness.
The chest pain was atypical and had some non-specific features. She had
no medical history and no family history of heart disease. On physical
examination, her blood pressure was normal (110/60 mmHg) and cardiac
auscultation revealed a grade 2/6 systolic murmur at the left sternal
border. Laboratory tests revealed normal blood count, renal and liver
function tests. Her ECG demonstrated right axis deviation, incomplete
right bundle branch block and right ventricular dilation.
Two-dimensional transthoracic echocardiography (2D-TTE) revealed normal
left ventricular size, mild left ventricular hypertrophy and systolic
function. Left ventricular outflow tract showed a large, mobile,
filamentous abnormal structure. The chordae of the anterior mitral
leaflet were intact. This tissue was found to prolapse into the LVOT
during systole. The morphology was suggestive of an AMVT. In addition,
TTE and TEE showed a wide secundum-type ASD with moderate dilatation of
the right heart chambers and mild aortic regurgitation (AR) (Fig 1).
However, the 2D-TTE images were not perfect and therefore
three-dimensional transesophageal echocardiography (3D-TEE) was planned.
Three-dimensional TEE provided anatomical information about other
cardiac structures. Transesophageal echocardiography showed that the
AMVT was attached to the ventricular portion of the anterior mitral
valve leaflet, which prolapsed in and out of the LVOT, causing only mild
LVOT obstruction (mean gradient 42 mmHg) and mild AR (Fig 2).
In this case, the physicians opted for surgical excision of the AMVT
because of the development of LVOT obstruction and AR. In addition, the
patient was not suitable for ASD transcatheter closure because of the
flail atrial septum and insufficient aortic rim. Excision of the AMVT
was easily achieved by aortotomy without the need for a left atriotomy.
The ostium secundum ASD was closed with a pericardial patch. In the
postoperative period, there was no LVOT obstruction and AR.