Approximately 70% of SCAs occur in the home, and the rate of survival to hospital discharge after AED placement by emergency medical services is significant- ly lower for arrest at home (12%) versus public settings However, in an RCT of AEDS, home AED placement did not improve the survival of patients re- covering from an anterior MI.S11.3-12 Appropriate device location to reduce time delay after onset of SCA is criti- cal. In addition to prevention, critical components of survival from SCA include immediate recognition and activation of the emergency response system, early high-quality CPR, and rapid defibrillation for shockable 12. SPECIAL CONSIDERATIONS FOR CATHETER ABLATION Recommendations for Catheter Ablation References that support the recommendations are summarized in Online Data Supplement 57. COR LOE Recommendations I C-LD In patients with bundle-branch reentrant VT, catheter ablation is useful for reducing the risk of recurrent VT and ICD shocks.S12-1 S12-3 IIa B-NR In patients with structural heart disease who have failed endocardial catheter ablation, epicardial catheter ablation can be useful for reducing the risk of recurrent monomorphic Synopsis Bundle-branch reentrant VT is due to reentry involving the bundle branches. Catheter ablation is the preferred therapy for this VT, which is encountered in <10% of patients with recurrent sustained monomorphic VT and structural heart disease (see Section 7.2.3). Recommendation-Specific Supportive Text 1. Bundle-branch reentrant VT can occur in any form of heart disease associated with slow infra- Hisian conduction. The most common mecha- nism involves antegrade conduction over the right bundle branch and retrograde conduction over the left bundle branch, thereby produc- ing left bundle-branch block QRS morphology during VT, which is often rapid and poorly tol- erated. 