Changing place, changing future: Repositioning a subcutaneous implantable cardioverter-defibrillator can resolve inappropriate shocks secondary to myopotential oversensing

Introduction The clinical benefits of implantable cardioverter-defibrillator (ICD) therapy have been widely documented in clinical studies of selected patient populations. Subcutaneous ICD (S-ICD) is a valid alternative to transvenous ICDinpatientswhodonot require cardiac resynchronization or antibradycardia or antitachycardia pacing, and has the additional advantage of avoiding possible acute and chronic complications secondary to transvenous lead implantation. Young patients facing multiple procedures (device replacement, lead revisions) are at higher risk of these complications, which makes them optimal candidates for an S-ICD. One of the most frequent adverse effects associated with ICD is the delivery of inappropriate shocks, which, in patients implanted with an S-ICD, are mainly secondary to oversensing and are often resolved by reprogramming the device. However, in rare cases this noninvasive approach is unable to eliminate inappropriate therapy and the device has to be replaced by a transvenous ICD, thus leading to the risk of transvenous lead–related morbidity. We here describe the case of a young patient diagnosed with catecholaminergic polymorphic ventricular tachycardia (CPVT) and implanted with an S-ICD, who received an inappropriate shock secondary to the oversensing of myopotential noise, which persisted despite the changes made to the device settings. Repositioning the can, which increased the amplitude of the sensed R waves and the R wave–to-noise ratio, proved to be effective in eliminating the myopotential oversensing and avoiding the need for a transvenous ICD.