Arterial gas embolism (AGE) is a main iatrogenic complication resulting from the use of invasive procedures. It is difficult to diagnose if it is not clinically suspected.A 67-year-old male patient, with a history of interventions involving a mitral prosthesis and a double aortocoronary bypass, who visited Emergency room with symptoms of a high temperature and general malaise. He was canalised peripherally and the electrocardiogram (ECG) showed an auricular fibrillation that had already been detected. While under observation he suffered a loss of consciousness, generalised hypotonia, conjugated gaze deviation towards the right, lower left facial paralysis and left Babinski positive. A new ECG showed ST segment elevation in V2-V5. A cranial computerised tomography (CAT) scan with no contrast revealed a number of serpiginous images caused by the presence of air in vascular structures. A second cranial CAT scan showed the disappearance of the visible air and signs of ischemic stroke in the territory of the right middle and posterior cerebral arteries and the left middle cerebral artery. Clinical-radiological findings suggested an AGE in the brain with massive stroke and acute myocardial infarct with similar causation.It is not clear what caused the air embolism in this patient but it can most probably be explained by air accidentally entering a peripheral vein. Carrying out an early cranial CAT scan can provide us with a diagnosis and a later CAT scan can evaluate the consequences of the embolism.