European Journal of Echocardiography 2008 9(1):160-161; doi:10.1016/j.euje.2007.05.008
Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2007. For permissions please email: journals.permissions@oxfordjournals.org
Dynamic mild subaortic left ventricular obstruction caused by an accessory mitral valve attached to the anterior mitral valve in a young pregnant woman
Antonio D'Aloia,
Enrico Vizzardi*,
Ermanna Chiari,
Francesco Fracassi,
Gregoriana Zanini,
Pompilio Faggiano and
Livio Dei Cas
Unità Operativa di Cardiologia, Spedali Civili, Brescia e Cattedra di Cardiologia, Università di Brescia, Brescia, Italy
Received 24 April 2007; accepted after revision 20 May 2007; online publish-ahead-of-print 23 August 2007.
* Corresponding author. E-mail address: enrico.vizzardi{at}tin.it
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Abstract
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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.
Keywords: Subaortic left ventricular obstruction; Accessory mitral valve; Pregnancy
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Background
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Accessory mitral valve tissue is an extremely rare congenital
cardiac anomaly of embryologic development of the endocardial
cushion firstly described by McLean in 1963.
1 This anomaly is
often associated with left ventricular outflow tract obstruction
(LVOTO)
1,2 and, most rarely, with interventricular septal defect.
3 The obstruction can occur in the early period of life as a result
of mass effect due to continued deposition of fibrous tissues
within the left ventricular outflow tract (LVOT). The accessory
mitral valve tissue is usually diagnosed in the first or second
decade of life and the main symptoms are exercise intolerance
with dyspnoea, chest pain and syncope.
2
An accurate echocardiographic evalutation of this entity and assessment of its hemodynamic consequences are very important for an appropriate therapeutic decision to be made.
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Case report
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A 26-year-old pregnant female was referred to our Department
of Cardiology with exertional shortness of breath and tachycardia.
She was a normally developed young woman, without history of
heart disease. At admission blood pressure was reduced (100/70
mmHg), with moderately high heart rate (100 beat/minute). At
auscultation an ejection type, 2/6 systolic murmur was heard.
Biochemical and hematological parameters were in the normal
range. The electrocardiogram showed sinus tachycardia (100').
Chest X-ray was normal.
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 (AML), with chordal attachments structure from anterior papillary muscle. This picture is compatible with a parachute-like accessory mitral valve tissue, without cleft in the AML. Other echocardiographic findings were normal except for a mild mitral regurgitation, and sign of LVOTO (rest normal LVOT pressure gradient) was not detected (Figures1 and 2, movie 1 and 2).
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Figure 1 In the photograph a normal and a zoomed apical four-chamber view indicates (arrow) the accessory mitral valve tissue, diameter 1.3 cm x 1.46 cm attached to the anterior mitral leaflet with a couple of chorda-like tissue segments.
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Figure 2 In the photograph a normal and a zoomed apical four-chamber view indicates (arrow) the accessory mitral valve tissue, diameter 1.3 x 1.46 cm attached to the anterior mitral leaflet with a couple of chorda-like tissue segments.
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We performed an echocardiographic exercise test in order to
exclude a dynamic and worsening of LVOTO. At color Doppler examination,
there was a systolic flow turbulence starting immediately proximal
to this structure, resulting in as small increase in LVOT gradient
(30 mmHg), but without symptoms.
Therefore we started low dose of beta-blocker therapy in order to decrease heart frequency and reduce the future risk of a worsening of the LVOT dynamic obstruction.
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Discussion
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Accessory mitral valve tissue is a congenital cardiac anomaly
that often manifests itself in the first decade of life, and
usually requires surgical reparation. Clinical manifestations
are exercise intolerance, chest pain, syncope, tachycardia and
they are usually due to left ventricular outflow tract obstruction.
2 Rarely it can be associated to thromboembolic accidents (two
cases are described in literature in the same patient).
4 Transthoracic
and transesophageal echocardiography is critical for the differential
diagnosis of LVOT and in the management of accessory mitral
valve tissue.
5,6 Surgical removal is indicated in patients presenting
significant LVOTO, even if they are asymptomatic, in patients
ongoing correction of other congenital malformations or exploration
of an intracardiac mass.
2 In our patient we did not find a significant
LVOTO and no other abnormalities were present.
In conclusion 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 indicated6 and a regular follow up is recommended to identify any progression in LVOTO entity.
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Supplementary material
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Supplementary data associated with this article can be found in the online version.
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References
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- McLead LD, Culligan JA, Kane DJ. Subaortic stenosis due to accessory tissue on mitral valve. J Thorac Cardiovasc Surg (1963) 45:382–7.[Web of Science]
- Prifti E, Bonacchi M, Bartolozzi F, Frati G, Leacche M, Vanini V. Postoperative outcome in patients with accessory mitral valve tissue. Med Sci Monit (2003) 9:RA146–53.
- Izumoto H, Ishihara K, Ogawa M, Fujii Y, Oyama K, Kawazoe K. Nonobstructing accessory mitral valve tissue and ventricular septal defect. Ann Thorac Surg (1996) 62:1846–8.[Abstract/Free Full Text]
- Yetkin E, Turhan H. Recurrence of cerebrovascular thromboembolic event in a woman with accessory mitral valve during puerperium period. Int J Cardiol (2005) 105:102–3.[CrossRef][Web of Science][Medline]
- Eiriksson H, Midgley FM, Karr SS, Martin GR. Role of echocardiography in the diagnosis and surgical management of accessory mitral valve tissue causing left ventricular outflow tract obstruction. J Am Soc Echocardiogr (1995) 8:105–7.[CrossRef][Medline]
- Popescu BA, Ghiorghiu I, Apetrei E, Ginghina C. Subaortic stenosis produced by accessory mitral valve: the role of echocardiography. Echocardiography (2005) 22:39–41.[CrossRef][Web of Science][Medline]
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