A 53 year old man with a history of Williams syndrome, an uncommon connective tissue disorder, presented to the ER with a brief episode of right gaze deviation with return to baseline, 25 days after a cardiac ablation procedure. He was febrile to 102.4F. Initial CT head was unremarkable. After a third episode of right gaze deviation and right hemiparesis, he experienced respiratory arrest. He was intubated and became hemodynamically unstable, despite vasopressors. Repeat CT scan demonstrated diffuse pneumocephalus, severe cerebral edema, and transtentorial herniation. Air was also seen in the intracranial vessels. Blood cultures were positive for multiple streptococcus species.

The initial differential diagnosis included seizures with Todd’s paralysis, stroke, and meningitis. On autopsy, he was found to have an atrioesophageal fistula (AEF) with endocardial thrombus. Cause of death was suspected to be bacterial endocarditis with systemic emboli. Air embolization is an extremely rare complication of cardiac ablation procedures, reported as between 0.01 to 0.2% in the literature, with emboli usually being blood or food, which was also seen in the brain on autopsy in this case. Symptoms may occur 3 to 41 days post-procedure, and may include fever, neurological deficits, and hematemesis. The preferred diagnostic test for AEF is CT chest imaging.