A subsequent meta-analysis using data from 3 RCTs showed a statistically significant reduction in both arrhythmic and all-cause mortal- ity with secondary prevention ICDs.S7.1.1-3 In survivors of life-threatening VA that may be due to transient or reversible factors, such as AMI, proarrhythmic medication effects, or electrolyte disturbances, an ICD is not implanted if the cause may be correctable. This is a population of patients that still requires thorough evaluation, treatment, and close follow-up and, as in the AVID registry, mortality was still high in the population that may have had a reversible cause for their arrest.S7.1.1-8 Small increases in troponin present a challenge in selecting patients for an ICD, as it often cannot be determined whether troponin elevation is due to ischemia from VT/VF and resuscitation, in which case an ICD is likely warranted, or an indication that ischemia caused the arrhythmia, in which case pre- vention of ischemia would be the therapeutic focus. ICDs may improve the outcomes of patients with hemodynamically tolerated sustained VT and structural heart diseaseS7.1.1-5 ; however, this has not proved in any RCT. VT ablation has been used as an alternative in selected patients with well-tolerated VT and appears to reduce recurrences, but the impact on long-term mortality is unknown; there is not yet sufficient evidence to recommend this approach as an alternative to ICD implantation.S7.1.1-9,S7.1.1-10 2. Economic outcomes of ICD implantation for second- ary prevention of SCD were assessed in the AVID and CIDS trials,S7.1.1-11,S7.1.1-12 as well as in a simulation and an observational study of Medicare All studies compared ICD recipi- ents with non-ICD recipients, and all found that ICD recipients had longer overall survival and higher lifetime costs of medical care. 