COR LOE Recommendations I B-NR In young patients (<40 years of age) with unexplained SCA, unexplained near drowning, or recurrent exertional syncope, who do not have ischemic or other structural heart disease, further evaluation for genetic arrhythmia syndromes is I B-NR In patients resuscitated from SCA due to idiopathic polymorphic VT or VF, an ICD is recommended if meaningful survival greater than 1 year is expected.S8.4-9 S8.4-13 I B-NR For patients with recurrent episodes of idiopathic VF initiated by PVCs with a consistent QRS morphology, catheter ablation is useful.S8.4-11,S8.4-14 Recommendation-Specific Supportive Text 1. When combined with clinical evaluation, genetic testing can provide a diagnosis in up to 13% to 60% of younger (<40 years of age) survivors with the most common genotypes identified associated with long QT syndrome, catecholaminergic polymorphic ventricular tachy- cardia, and Brugada syndrome.S8.4-8 Drowning/ near drowning events are particularly associated with LQT1 and catecholaminergic polymorphic ventricular tachycardia; genetic mutations in long QT syndrome and catecholaminergic polymorphic ventricular tachycardia have been identified in 23% of patients with unexplained near-drown- exertion-related cardiac arrest, particularly in children, may be related to long QT syndrome, catecholaminer- gic polymorphic ventricular tachycardia, or to calmodulin/triadin-mediated long QT syndrome/ catecholaminergic polymorphic ventricular tachy- cardia mutations, which may require additional specialized genetic testing.S8.4-1,S8.4-2,S8.4-4,S8.4-16 S8.4-18 Single-driver auto crashes should prompt the consideration of arrhythmic causes. The yield of genetic testing is higher if a family history of SCD at a young age is present. Referral to specialized genetic testing centers is important if local exper- tise is unavailable. 2. 