Double orifice mitral valve
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vendhan Ramanujam M.B.B.S [2]
Synonyms and keywords: DOMV
Overview
A double orifice mitral valve (DOMV) is a rare congenital malformation characterized by two valve orifices with two separate subvalvular apparatus. It is mostly associated with atrioventricular septal defect, but may also be associated with other congenital heart defects such as left-sided obstructive lesions, ventricular septal defects or cyanotic lesions. Isolated DOMV have been rarely reported.
Classification
Based on the size and location of the two orifices, various classifications for DOMV have been proposed. Trowitz et al. described three different types of DOMV using the 2D echocardiographic findings[1]
| DOMV Type | Characteristics |
| Complete bridge type | Both orifices are visible from the leaflet edge, all the way through the valve ring. Both openings are circular (equal or unequal in size), papillary muscles usually are normal, with chordae surrounding each orifice inserting into one papillary muscle. |
| Incomplete bridge type | Connection is seen only at the leaflet edge, resulting in a double circle only at the leaflet level, with a normal appearance in the more basal views. |
| Hole type | Small accessory orifice situated at either the anterolateral or posteromedial commissure, visible only at the mid-leaflet level and disappearing on scanning toward the apex or base. |
A fourth type of DOMV, duplicate mitral valve with two annuli and valves, each with its own set of leaflets, commissures, chordae, and papillary muscles have been described by some authors.[2]
Pathophysiology
While the normal mitral valve consists of a large central orifice located between the large anterior leaflet and the small posterior leaflet, in DOMV, an abnormal tissue divides the large central orifice into 2 parts. This division of the large central orifice might reduce the total area of the mitral valve orifice, obstructing its inflow and causing mitral stenosis. When the inflow obstruction is significant, the left atrial and pulmonary venous pressure rises, leading to exudation of fluid into the interstitium of the lung and frank pulmonary edema. Persistent pulmonary venous hypertension leads to pulmonary arterial hypertension and eventually the failure of the right ventricle with tricuspid regurgitation. Mitral regurgitation is the commonest hemodynamic abnormality associated with DOMV. Similar to mitral stenosis, mitral regurgitation causes left atrial and pulmonary venous hypertension. Left ventricular outflow obstruction can aggravate the mitral regurgitation, leading to more severe clinical presentations like irreversible ventricular dysfunction, marked enlargement of left atrium with subsequent compression of left bronchus, and worsening pulmonary hypertension with right heart failure.
Epidemiology and Demographics
References
- ↑ Trowitzsch, E.; Bano-Rodrigo, A.; Burger, BM.; Colan, SD.; Sanders, SP. (1985). "Two-dimensional echocardiographic findings in double orifice mitral valve". J Am Coll Cardiol. 6 (2): 383–7. PMID 4019924. Unknown parameter
|month=ignored (help) - ↑ Wójcik, A.; Klisiewicz, A.; Lusawa, T.; Hoffman, P. (2005). "[Double-orifice mitral valve -- case report]". Kardiol Pol. 63 (6): 663–5. PMID 16380874. Unknown parameter
|month=ignored (help)