Is shock impedance value alone to be considered a good predictor for shock efficacy in subcutaneous implantable cardioverter defibrillator?

Subcutaneous implantable cardioverter defibrillator (S-ICD) is easy to implant, with poor risks of the patient. However, fat is a poor current conductor and increases defibrillation threshold. As shock impedance alone should not be considered a good efficacy predictor of an S-ICD system, an X-ray latero-lateral view for lead position should be achieved.