Maron MS, et al. - In this observational longitudinal study, researchers investigated if sudden cardiac death (SCD) prediction methods are reliable for reducing SCDs in patients with hypertrophic cardiomyopathy (HCM) via prophylactic implantable cardioverter/defibrillators (ICDs). Over a 17-year experience at a single HCM center, ICD decision making for 2,094 patients with HCM was prospectively evaluated based on conventional major risk markers derived from the literature and enhanced from 2011 American College of Cardiology/American Heart Association guidelines. Rates of appropriate ICD therapy terminating potentially lethal ventricular tachyarrhythmias exceeded SCDs in patients without ICDs by almost 50-fold. SCD events in nearly all at-risk patients with HCM were predicted by a systematic enhanced ACC/AHA guideline and practice-based risk factor strategy, which led to prophylactically implanted ICDs that prevented countless disastrous arrhythmic events in this at-risk population.