Case report of multi-modality imaging of a double interatrial septum, an unusual cause of cryptogenic stroke.

Case description

A 58-year-old female patient with a history of invasive mammary carcinoma, obesity, arterial hypertension, and dyslipidaemia presented with transient dysarthria and facial palsy. Brain computed tomography (CT) and EEG were unremarkable. Therapy with aspirin was started. Oncologic re-evaluation with mammogram, breast ultrasound, and positron emission tomography showed no arguments for malignancy. Magnetic resonance imaging (MRI) of the brain showed multiple cortical and subcortical lesions compatible with recent ischaemia, prompting a further search for a cardioembolic source. Duplex ultrasonogram of the carotid arteries, electrocardiogram, and transthoracic echocardiography were within normal limits. On prolonged heart rhythm monitoring, evidence for paroxysmal atrial fibrillation was lacking. Three-dimensional transesophageal echocardiography showed a double interatrial septum containing spontaneous echo contrast, suspect for a thrombus (). Colour flow Doppler showed an opening to the left atrium without any opening to the right atrium nor passage of agitated geloplasma after Valsalva manoeuvre and release. A cardiac CT scan confirmed the presence of a double interatrial septum, but the spatial resolution was lacking to confirm the presence of a thrombus.

(A) 3D TEE images with X-plane imaging of the double interatrial septum containing spontaneous echo contrast (arrowhead), (B) 3D TEE image of the double interatrial septum with an opening to the left atrium (arrow). AV, aortic valve; LA, left atrium; RA, right atrium.

A double interatrial septum is a rare congenital anomaly.[1] It is thought to be the result of the persistence of the embryologic left venous valve derived from the embryologic sinus venosus or the persistence of either the primum or secundum atrial septal tissue.[2] Stasis of blood within the interatrial space may result in thrombus formation and systemic embolization.[3] Current knowledge about this anomaly is based on case reports, and the need for treatment remains unclear. Since our patient had ischaemic brain lesions in multiple vascular distributions on MRI, we opted for treatment with edoxaban 60 mg once daily and termination of the aspirin derivate. Clinical follow-up after 3 months showed the patient in good health without any recurrence of cardioembolic events.

Consent: The authors confirm that consent for submission and publication of this case has been obtained from the patient.

Conflict of interest: None declared.

Funding: None declared.