Due to the increased risk of adverse car- diac events in genotype positive patients with long QT syndrome, catecholaminergic poly- morphic ventricular tachycardia, and Brugada syndrome, targeted screening for the identified family-specific mutation can identify individuals who are at risk for these adverse outcomes.S7.9- Screening ECGs may be insufficient for diagnosis, because the resting ECG in patients with catecholaminergic polymorphic ventricular tachycardia is normal, and as many as 25% of genotype-positive patients with long QT syn- drome have QTc intervals 440 ms.S7.9-2 Due to the increased risk of adverse cardiac events in young patients with long QT syndrome and catecholaminergic polymorphic ventricular screening infants and young children is particularly important to guide therapy and institute preventive measures, including the avoidance of possible provoca- tive medications (www.crediblemeds.org).S7.9-23 However, because up to 15% of mutations pre- viously associated with catecholaminergic poly- morphic ventricular tachycardia do not appear to cause disease,S7.9-24 caution is advised to avoid unnecessary treatment or sports restriction in phenotype-negative catecholaminergic polymor- phic ventricular tachycardia mutation positive individuals. Notably, some patients may prefer not to undergo genetic testing, so genetic coun- seling should focus on this issue. 2. Patients with cardiac channelopathies (ie, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, early repolarization syndrome, and short QT syndrome) and prior SCA have a significantly increased risk of subsequent SCA or SCD.S7.9-7 S7.9-13,S7.9-25 S7.9-28 Implantation of an ICD reduces the risk of death in high-risk patients.S7.9-9,S7.9-29 S7.9-31 Appropriate ICD therapy for VF/fast VT is reported in 8% to 33% of channelopathy patients, while inappropri- ate shocks and device complications are reported To mini- mize inappropriate shocks, concurrent beta block- ers in long QT syndrome and catecholaminergic polymorphic ventricular tachycardia patients, optimal device programming, and appropriate lead selection are necessary. 