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.