Discussion:
Our case illustrates a type B DCLV and is the first case in which
antenatal images are available.
Differential diagnosis includes diverticulum or aneurysm of the left
ventricle. In the former the outpouching has 3 layers, contracts during
systole and has a narrow connection with the LV. In the later,
connection with the LV is large and the cavity does not contract or is
dyskinetic [2]. In our patient the outpouching had a wide connection
to the LV from which it was separated from muscle bundles but had
initially a normal contractility characterizing DCLV.
Several authors consider that type B DCLV is a benign condition
frequently found incidentally [1;3-6]. It can also be complicated by
dysrhythmias [7] or by left ventricular dysfunction as in our case
[8]. It is likely that the size of the AC influences the long-term
tolerance of the anomaly since a large AC causes chronic volume overload
of the left ventricle that could lead to LV dysfunction. Indeed, in a
report of more than 800 cases of left ventricular aneurysm or
diverticulum Ohlow et al. noticed that LV dysfunction occurred in the
largest outpouchings [9].
Thus, type B DCLV is an exceedingly rare congenital heart malformation
that can be diagnosed during fetal life. Although most of reported cases
have a benign outcome and are asymptomatic, its prognosis probably
depends on the size of the AC, large AC could result in chronic LV
overload and dysfunction. Prenatal family counselling should mention
this possible evolution.