Discussion
We present a case of a 43-year-old female who had left posterior
cerebral artery ischemia and an atrial septum aneurysm on
echocardiography. An atrial septum becomes aneurysmal when an atrial
dilated segment bulges at least 15 mm beyond the atrial septum’s surface
level [4]. Atrial septal aneurysm and/or patent foramen ovale are
thromboembolic heart defects. Both occur in 20% of the population and
contribute to cryptogenic ischemic strokes in the younger population.
Cryptogenic strokes are those with unknown or unexplained aetiologies
[5]. Cerebrovascular events can occur in up to 52% of patients with
atrial septum aneurysms. However, this significant incidence is found in
patients with a clear cardiac thromboembolic cause of the
cerebrovascular episode. The pathogenesis of stroke in people with
atrial septum aneurysms is not completely known. It could be related to
the production of direct thrombi at the atrial septum aneurysm [6].
Right-to-left paradoxical embolism of venous thrombi through a patent
foramen ovale is another cause of cerebral embolism, as is the
transition of a thrombus developed on the left atrial side of an
aneurysm [5,7]. Transoesophageal echocardiography is commonly used
to detect atrial septal aneurysms in individuals with unexplained
strokes [8]. Our patient experienced cerebrovascular symptoms, but
transthoracic echocardiography revealed only aneurysmal interatrial
septum, no Patent Foramen ovale or another shunt, no intracardiac
thrombus, or vegetation, ruling out several of the known potential
explanations. However, because of the presence of bulbar cranial nerve
palsy, we were unable to get a transoesophageal echo, which could have
clarified the cause of the stroke. Possible underlying mechanisms
include the formation of a thrombus on the aneurysm’s left atrial side
or the development of interatrial fenestrations that resulted in a
right-to-left shunt. Because hypertension has been linked to cryptogenic
stroke, we believe it played a role in the aetiology of cryptogenic
stroke in our patients [9]. Our case emphasizes the significance of
atrial septum aneurysm as a potential risk factor for cryptogenic
ischemic strokes. To the best of our knowledge, this is the first case
of a symptomatic stroke patient with an atrial septal aneurysm on
transthoracic echocardiography that does not have a patent foramen ovale
or any other aetiology. More research is needed to determine the
mechanism underlying such cerebrovascular events.