Subcutaneous Implantable Cardioverter-Defibrillator Recommendations for Subcutaneous Implantable Cardioverter- Defibrillator References that support the recommendations are summarized in Online Data Supplement 55. COR LOE Recommendations I B-NR In patients who meet criteria for an ICD who have inadequate vascular access or are at high risk for infection, and in whom pacing for bradycardia or VT termination or as part of CRT is neither needed nor anticipated, a subcutaneous implantable cardioverter-defibrillator is IIa B-NR In patients who meet indication for an ICD, implantation of a subcutaneous implantable cardioverter-defibrillator is reasonable if pacing for bradycardia or VT termination or as part of CRT is neither needed nor III: Harm B-NR In patients with an indication for bradycardia pacing or CRT, or for whom antitachycardia pacing for VT termination is required, a subcutaneous implantable cardioverter-defibrillator should not be Synopsis In patients being considered for a subcutaneous im- plantable cardioverter-defibrillator, a preimplant ECG to establish QRS-T wave morphology is needed to re- duce the risk of under sensing of VT/VF and the risk of inappropriate shocks.S11.1-9 S11.1-11 The subcutaneous implantable cardioverter-defibrillator is implanted using primarily anatomical landmarks, thereby minimizing the need for fluoroscopy. The subcutaneous implantable cardioverter-defibrillator consists of a pulse generator that is placed at the midaxillary line between the fifth and sixth intercostal spaces and a lead with 2 sensing electrodes and a shocking coil, positioned subcutane- ously adjacent to the sternum. As with the transvenous ICD, the pulse generator housing serves as an electrode for defibrillation but, in addition, it can also serve as an optional electrode for sensing. The subcutaneous implantable cardioverter-defibrillator cannot achieve adequate arrhythmia sensing for all patients, and elec- trocardiographic screening to assess sensing is required prior to implantation.S11.1-10,S11.1-11 Some advocate exer- cise testing after device implantation to ensure proper sensing with exercise. 