Early inappropriate shock in a subcutaneous cardiac defibrillator due to subcutaneous air

A 57‐year‐old man was admitted to our hospital due to syncopal attack. He was diagnosed with Brugada syndrome due to which a subcutaneous implantable cardiac defibrillator (S‐ICD) was inserted using the standard technique. Two hours after the implantation, he experienced inappropriate shock while conscious. Device interrogation revealed a contentious baseline shift and frequent oversensing of low‐amplitude signals, which was followed by a shock. Lateral chest X‐ray revealed subcutaneous air surrounding the proximal electrode. Another inappropriate shock could be avoided by changing the sensing vector. The subcutaneous air was completely resolved 7 days after implantation.