Several studies have described an indepen- dent relationship between hypertrophy and SCD when the magnitude of hypertrophy is Risk does not abruptly increase for patients with a 30 mm wall thick- ness, but it rather increases in a linear mannerS7.4-24 and appears to carry more prognostic significance in younger patients. A young adult with hypertro- phy that approaches 30 mm may have similar or greater SCD risk than an older patient with maxi- mum wall thickness 30 mm.S7.4-23,S7.4-50 Patients with HCM are at an increased risk for SCD if they have a first-degree relative who expe- rienced SCD presumably caused by HCM. Family history appears to be an independent predictor of SCD although the supportive studies are small Syncope can be neu- rally mediated or medication-related as well as due to VA and requires a careful evaluation be- fore considering it a risk factor for SCD.S7.4-8,S7.4-26 In an analysis, syncope that was unexplained or thought not to be neurally mediated was associ- ated with SCD risk only when it occurred within the past 6 months but not if the most episode 7. Although sustained VT is clearly associated with SCD, the data for NSVT are less robust. 