A 56-year-old man underwent radiofrequency ablation for atrial fibrillation. Four weeks later he presented with sepsis and neurological symptoms. Urine analysis demonstrated the presence of blood and protein. A CT scan showed pockets of air in the left atrium. An MRI brain scan revealed multiple cerebral abscesses. The patient developed a third heart sound and splinter haemorrhages. He was subsequently referred to cardiology for transoesophageal echocardiography after starting a course of intravenous meropenem. The cardiology team noted that this individual presented with a triad of infections, neurological sequelae and air in the left atrium after an ablation procedure and diagnosed atrio-oesophageal fistula. A decision to operate was made 9 days after admission. At surgery an area of caseous ulceration was found on the posterior wall of the left atrium overlying the oesophagus. PCR analysis revealed Mycoplasma salivarium, part of the oral flora.