Cardiac Channelopathies Recommendations for Cardiac Channelopathies References that support the recommendations are summarized in Online Data Supplement 39. COR LOE Recommendations I B-NR In first-degree relatives of patients who have a causative mutation for long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, short QT syndrome, or Brugada syndrome, genetic counseling and mutation-specific genetic testing are I B-NR In patients with a cardiac channelopathy and SCA, an ICD is recommended if meaningful survival of greater than 1 year is Synopsis Implantation of an ICD in asymptomatic low-risk pa- tients with a cardiac channelopathy for a positive family history of SCD as the sole indication is unsupported by Recommendation-Specific Supportive Text 1. Clinical screening of first-degree relatives of patients with inherited arrhythmia syndromes is crucial to identifying affected family mem- bers. 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. 