1. Benjamin H. Hammond, MD* 2. Kenneth G. Zahka, MD* 3. Peter F. Aziz, MD* 1. *Department of Pediatric Cardiology, Cleveland Clinic Children’s, Pediatric Institute, Cleveland Clinic Foundation, Cleveland, OH * Abbreviations: ACC: : American College of Cardiology AED: : automated external defibrillator ARVC: : arrhythmogenic right ventricular cardiomyopathy CPVT: : catecholaminergic polymorphic ventricular tachycardia ECG: : electrocardiogram HCM: : hypertrophic cardiomyopathy ICD: : implantable cardioverter-defibrillator LQTS: : long QT syndrome LVNC: : left ventricular noncompaction cardiomyopathy LVOT: : left ventricular outflow tract RV: : right ventricle SADS: : sudden arrhythmic death syndrome SCA: : sudden cardiac arrest SCD: : sudden cardiac death TdP: : torsade de pointes VA: : ventricular arrhythmia VT: : ventricular tachycardia 1. There is a broad differential diagnosis to be considered in cases of sudden cardiac arrest, sudden cardiac death. 2. Timely diagnosis can circumvent progression to cardiac arrest in at-risk individuals. 3. All children should be screened and testing should be reserved for those with increased risk. After completing this article, readers should be able to: 1. Assess risk of sudden cardiac arrest/sudden cardiac death (SCA/SCD) with a screening history and physical examination. 2. Identify the mechanisms of distinct etiologies of SCA/SCD. 3. Recognize findings consistent with risk of SCA/SCD on a 12-lead electrocardiogram. 4. Address the concerns and questions of individuals and families after SCA/SCD. Sudden cardiac death (SCD) or sudden cardiac arrest (SCA) may occur in populations known to be at high risk or in individuals previously unrecognized to harbor underlying disease. This review focuses on the pediatrician’s role in identifying the latter group. SCA is a “severe malfunction or cessation of the electrical and mechanical activity of the heart, resulting in almost instantaneous loss of consciousness and collapse” that precedes SCD. (1) SCD is defined as rapid, unexpected death from cardiac causes that occurs within 1 hour of symptoms. (2) SCD that is known to be secondary to a primary arrhythmia is termed sudden arrhythmic death syndrome (SADS) . SCA is a common cause of death in adults, with the annual incidence estimated to be approximately 100 per 100,000, with variation seen with age, sex, and race. (3) These deaths are predominantly associated with coronary artery disease. In individuals younger than 18 years, SCA is much less common, with an estimated annual incidence of out-of-hospital cardiac arrest of 8.3 per 100,000 person-years. (4 …