A man with an ischemic cardiomyopathy and chronic obstructive pulmonary disease underwent subcutaneous implantable cardioverter-defibrillator (S-ICD) placement under general anesthesia. Following induction of ventricular fibrillation (VF), defibrillation testing (65J) failed, requiring external rescue. Repeat shock testing with reversed polarity (65J) failed. A third shock and external defibrillation failed (80J and 200J), followed by a second external defibrillation (200J), which did not immediately terminate VF, and a device shock 2 seconds later (80J, successful). Repeat shock testing (80J) under conscious sedation without mechanical ventilation was successful. We discuss this case of failed defibrillation testing during S-ICD placement, potentially due to lung hyperinflation, requiring double sequential defibrillation.