Failure in the functioning of an implanted automatic defibrillator due to pneumothorax occurring during its implantation

: A 67-year-old man with chronic bronchitis and coronary artery disease was scheduled to receive an implantable cardioverter defibrillator (ICD) after an episode of sustained monomorphic ventricular tachycardia. During implantation through the left subclavian vein, oxygen saturation decreased to slightly below baseline. Nevertheless, the procedure continued, given that the patient experienced neither breathing difficulties nor pain. When the ICD failed to reverse ventricular fibrillation induced to test the device, an external defibrillator was used. At that point, left-sided pneumothorax was observed by x-ray. Air in the pleural cavity caused an increase in the defibrillation threshold. After insertion of a thoracic drain, the ICD implantation procedure was completed successfully.