Discussion
DOMV is a rare congenital cardiac malformation and around 5% of cases of AVCD have associated DOMV with them.1 The above entity can present itself as a normal functioning valve or less commonly, as mitral regurgitation (MR) or mitral stenosis (MS).5
The characteristic feature of DOMV is that, all the chordae of one papillary muscle go to one of the ostia while all of the chordae of the other papillary muscle go to the other ostia.6 This predisposes to stenosis if the cleft is extensively sutured, creating a parachute like configuration. The degree of valve narrowing (minimum orifice area), which is acceptable has not been determined, however, orifice of 65 to 70 % is well tolerated.7
Our patient had DOMV, AVCD, severe MR with major orifice only slightly larger than accessory orifice. .We opted for sequential approach, starting from the periphery of the major orifice and then moving towards the centre, thereby testing at each step, adequacy of the orifice to avoid stenosis. .We used Hegar’s dilators intra-operatively, to objectively assess the diameters of orifices, in order to calculate the area of both orifices for inflow into left ventricle (LV). It is preferable to accept mild regurgitation than to create a new significant stenosis.
As expected, treatment for non regurgitant cleft in DOMV, AVCD is controversial. Some may argue against closing the cleft, to create new stenosis, however, partial closure can prevent late development of MR. Accessory orifices are seldom more than mildly incompetent and hence can be left untouched. Suture or patch closure of regurgitant accessory orifice has been practised, but we believe, ratio of the two orifices must be taken into consideration before this kind of intervention.8
Watchful closure of the cleft to avoid new stenosis can be done in DOMV, AVCD, severe MR, with good early outcome, however late development of hemodynamically significant MR is always a possibility.