Dynamic mild subaortic left ventricular obstruction caused by an accessory mitral valve attached to the anterior mitral valve in a young pregnant woman

Abstract

Accessory mitral valve tissue is an extremely rare congenital cardiac anomaly of embryologic development of the endocardial cushion. This anomaly is often associated with left ventricular outflow tract obstruction (LVOTO). A 26-year-old pregnant female was referred to our Department of Cardiology with exertional shortness of breath and tachycardia. Transthoracic and transesophageal echocardiography revealed a flexible circular (1.3 x 1.4 cm), mobile structure attached to the ventricular side of anterior mitral valve leaflet, with chordal attachments structure from anterior papillary muscle. This picture is compatible with a parachute-like accessory mitral valve tissue. We performed an echocardiographic exercise test that shows a systolic flow turbulence starting immediately proximal to this structure, resulting in a small increase in left ventricular outflow tract (LVOT) gradient (30 mmHg). Therefore we started low dose of beta-blocker therapy in order to decrease heart frequency and reduce the future risk of a worsening of an LVOT dynamic obstruction. Transthoracic and transesophageal echocardiography is critical for the differential diagnosis of LVOT and in the management of accessory mitral valve tissue. In patients without rest and only an exertional mild LVOTO and no other cardiac malformations, prophylactic removal of mitral accessory tissue excision is not required; antibiotic prophylaxis for endocarditis can be indicated and a regular follow-up is recommended to identify any progression in LVOTO entity.

Unusual Cause of Heart Failure in a Patient with Marfan Syndrome: A Late Complication of Bioprosthetic Valved Graft Replacement

“…5 Risk factors for late reoperations are acute or chronic dissections at the time of initial surgery, aneurysms involving major peripheral arteries, hypertension, and a history of smoking. 6 Causes of increased echocardiographic Doppler gradients across the AV and LVOT include valvular stenosis, hypertrophic cardiomyopathy, 1 supravalvular aortic stenosis, 4 subaortic obstruction, 3 accessory mitral valve tissue attached to the ventricular side of the anterior mitral valve leaflet, 2 and mitral valve replacement with a high-profile mechanical or bioprosthetic valve. [7][8][9] This case illustrates an unusual cause of a high-velocity gradient along the LVOT that was unrelated to prosthetic AV…”

Accessory Mitral Valve Tissue: An Unusual Echocardiographic Finding

“…Regarding treatment of this anomaly, cardiac surgery is indicated only in patients with significant LVOT gradients and those undergoing correction of other congenital cardiac defects. 8 , 14 Surgery includes accessory tissue removal and, sometimes, artificial chordae implantation and annuloplasty, depending on the severity of the disease. 15 For patients without significant LVOT obstruction, follow-up with serial echocardiography to access progression of the gradient is indicated.…”

Accessory Mitral Valve Tissue: A Case Report and an Updated Review of Literature

“…Beyond the above 90 cases, we obtained 40 cases from 27 papers, 2‐28 five cases of which were from five Japanese articles that were cited by Yao et al, 5 and one case was from a Spanish study on heart specimen with no more detailed information 6 . Accordingly, there were a total of 131 cases of accessory mitral valve tissue including the present one.…”

“…Twenty-four (58.5%) patients underwent a surgical operation, in which a septal myectomy was performed in two patients as a unique operation instead of or as an integrated operation to resection of the aberrant tissue, 12,13 an associated mitral annuloplasty, and/or valvuloplasty in five, 11,[13][14][15] an associated mitral valve replacement in one, 4 an associated aortic valve replacement in three, 5,13,16 and the operative method was not mentioned in two patients, 9,26 respectively. Eleven (26.8%) patients did not receive an operation, due to no or mild LVOT obstruction, 2,5,17,18,27,28 an incongruity between symptoms of LVOT obstruction, and the value of pressure gradient caused by both accessory mitral valve tissue and bicuspid aortic valve, 2 or the patient's refusal. 2 Treatment method was unspecified in five (12.2%) cases.…”