Methodology and Evidence Review The recommendations listed in this clinical practice guide- line are, whenever possible, evidence-based. An initial extensive evidence review, which included literature de- rived from research involving human subjects, published in English, and indexed in MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Health- care Research and Quality, and other selected databas- es relevant to this guideline, was conducted from April 2016 to September 2016. Key search words included, but were not limited, to the following: sudden cardiac death, ventricular tachycardia, ventricular fibrillation, pre- mature ventricular contractions, implantable cardioverter- defibrillator, subcutaneous implantable cardioverter-defi- brillator, wearable cardioverter-defibrillator, and catheter ablation. Additional relevant studies published through March 2017, during the guideline writing process, were also considered by the writing committee, and added to the evidence tables when appropriate. The final evidence tables are included in the Online Data Supplement and summarize the evidence used by the writing committee to formulate recommendations. Additionally, the writing committee reviewed documents related to ventricular arrhythmias (VA) and sudden cardiac death (SCD) previ- ously published by the ACC, AHA, and the Heart Rhythm Society (HRS). References selected and published in this document are representative and not all-inclusive. As noted in the Preamble, an independent ERC was commissioned to perform a formal systematic review of 2 important clinical questions for which clear literature and prior guideline consensus were felt to be lacking or limited (Table 2). The results of the ERC review were considered by the writing committee for incorporation into this guide- line. Concurrent with this process, writing committee members evaluated other published data relevant to the guideline. The findings of the ERC and the writing com- mittee members were formally presented and discussed, then guideline recommendations were developed. 