Discussion :
Our case report underlines the special need for medical control in
patients with mitral valve stenosis and atrial fibrillation because of
the high incidence of left atrial thrombi [4,5] . In our
patient, the cardiac evaluation revealed a paroxysmal atrial
fibrillation with rheumatic mitral valve stenosis.
It is speculated that a fixed thrombus initially forms in the left
atrial appendage or the left atrial wall [6] . Afterwards,
it grows into a round shape, followed by disconnection of the pedicle
between the thrombus and the atrial wall [7] . Wall-adherent
thrombi can detach and float freely [8] . The detached
thrombus may be remodeled into the spherical shape by the sculpting
effect of multiple collisions with the atrial wall and result ball
thrombi [9] .
Abe and col advocated the classification of left atrial thrombi into
three types; movable ball type, fixed ball type and mountain type. They
demonstrated that the rate of embolism in the movable type group was
significantly higher than that in the other groups [10] . In
our case, it was a movable ball type and the embolic rate was very high[11] , but, among these, spinning
ball thrombi may have an even worse prognosis [6] .
The presence of a left atrial ball thrombus is linked to higher embolic
rates [12] . Although clinical evidence is sparse, prompt
surgical removal of the free floating thrombus, often in conjunction
with mitral valve repair or replacement, is the appropriate therapeutic
course in most patients [13] because re-embolization on
formal anticoagulation has been reported [14] .