Massive interventricular septal aneurysm and stroke in a healthy young patient: guilt by association?

Aneurysm of the membranous interventricular septum is an uncommon cardiac defect that is, on rare occasions, associated with embolic stroke. We describe here the case of an otherwise healthy, 41-year-old man who presented to the hospital with acute-onset confusion and left-sided body weakness attributed to a right middle cerebral artery ischemic stroke. He experienced a nearly complete resolution of deficits following systemic thrombolytic therapy. After an extensive workup, the presumed mechanism of stroke was a thromboembolus that originated in a massive aneurysm of the patient's membranous interventricular septum. Due to a perceived risk of surgical morbidity, the patient was managed conservatively with anticoagulation. He denied further events and reported nearly full function at follow-up.