Asymptomatic accessory mitral valve tissue diagnosed by echocardiography

Accessory mitral valve tissue: anatomical and clinical perspectives

Mitral valve is a complex cardiac structure composed of several components to work in synchrony to allow blood flow into left ventricle during diastole and not to allow blood flow into left atrium during systole. Accessory mitral valve tissue (AMVT) was defined as existence of any additional part and parcel of valvular structure which has an attachment to normal mitral valve apparatus in left-sided cardiac chambers. AMVT may present itself in different clinical circumstances ranging from a silent clinical course to thromboembolic events, heart failure, left ventricular outflow tract obstruction, and severe arrhythmia. This article reviews the clinical perspectives of AMVT in terms of symptoms, diagnosis, and treatment, providing a new anatomical classification regarding the location of AMVT. Briefly type I refers to AMVT having attachments on the supra leaflets level, type II refers to attachments on the mitral leaflets, and type III refers to attachment below the mitral leaflets. Increased awareness and widespread use of echocardiographic techniques would increase recognition of AMVT in patients with heart murmurs but otherwise healthy and in those with left ventricular outflow tract obstruction or tissue which causes subaortic stenosis and with unexplained cerebrovascular events.

A rare case of accessory mitral valve tissue causing left ventricular outflow tract obstruction associated with parachute mitral valve, ventricular septal defect, bicuspid aortic valve, unruptured aneurysm of aortic sinus: a case report

Background

Accessory mitral valve tissue rarely causes left ventricular outflow tract obstruction in adults. It is often associated with other cardiac and vascular congenital malformations. Here, we report the rarest presentation of accessory mitral valve tissue (AMVT) causing left ventricular outflow tract obstruction.

Case summary

A 22-year-old female patient presented with a history of shortness of breath and chest pain for more than 5 years. A diagnosis of AMVT with parachute mitral valve, ventricular septal defect (VSD), bicuspid aortic valve, unruptured aneurysm of aortic sinus, and left ventricular outflow tract obstruction was made. Successful closure of VSD with mitral valve replacement, excision of AMVT, and repair of the aortic sinus were performed. The post-operative course was uneventful, and an echocardiogram showed complete resection of the accessory mitral valve, no residual shunt and no left ventricular outflow gradient. Additionally, the peak gradient of rapid filling phase and atrial systolic phase across the prosthetic mitral valve were 16 mmHg and 4 mmHg, respectively. The peak velocity across left ventricular outflow tract was 1.4 m/s.

Discussion

Accessory mitral valve tissue is associated with other cardiac abnormalities and is usually diagnosed in the first or second decade of life. It is responsible for left ventricular outflow tract obstruction. The obstruction can occur in the early period of life due to continued deposition of fibrous tissues within left ventricular outflow tract. Accessory mitral valve tissue should be considered a rare but important cause of left ventricular outflow tract obstruction.

Latent Left Ventricular Outflow Tract Obstruction Due to Accessory Mitral Valve in a 12-Year-Old Boy

Accessory mitral valve (AMV) is a rare congenital anomaly which can cause left ventricular outflow tract (LVOT) obstruction. Patients with isolated AMV usually present with exertional dyspnea, chest pain, or syncope during the first ten years of life. In patients with AMV, detection of latent LVOT obstruction can be clinically challenging. We here present a case of AMV causing latent LVOT obstruction in an adolescent, which was diagnosed by echocardiography with dobutamine provocation and finally treated by successful surgical resection.

Unique congenital malformation of the mitral valve associated with anomalous coronary arteries and stroke

A 55-year-old male presented with stroke. Transesophageal echocardiogram and cardiac computed tomography revealed an unrecognized congenital malformation of the anterior mitral leaflet associated with anomalous left coronary circumflex artery, arising from the right coronary artery, diagnosed first by echocardiogram. This case represents a unique unforeseen mitral valve anomaly that might be considered as potential cardiac source of embolism. This finding broadens the spectrum of known mitral valve anomalies.