Screening for Sudden Cardiac Death in the Young

Abstract

Sudden cardiac death (SCD) in the young (SCDY) has a devastating impact on families, care providers, and the community and attracts significant public and media attention. Sudden cardiac death is defined as an abrupt and unexpected death due to a cardiovascular cause, typically occurring 1 hour from the onset of symptoms. Depending on the source, “young” is variably defined as those less than 25, 30, 35, or 40 years of age. Estimates of the incidence of SCDY (not including infants) vary broadly from 0.6 to 6.2 per 100 000 persons. 1–3 Sudden infant death syndrome (SIDS) may be related to SCD in some infants. Sudden infant death syndrome is defined as the sudden death of an infant 1 year of age that cannot be explained after a thorough investigation is conducted, including an autopsy, death scene evaluation, and review of the clinical history. The incidence of SIDS ranges from 50 to 100 in 100 000,4 and emerging data suggest that as many as 10% to 15% of SIDS deaths are associated with functional cardiac ion channelopathy gene variants.5 The most common diagnoses that increase risk for SCDY include hypertrophic cardiomyopathy (HCM), coronary artery anomalies of wrong sinus origin, myocarditis, arrhythmogenic right ventricular cardiomyopathy, and ion channelopathies.6 The latter category includes hereditary diseases such as the congenital long-QT syndromes (LQTS), catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome, among other less common channelopathies. These diseases are typically undetected before the SCD event. Estimated prevalence rates of these conditions range from 1 per 500 persons for HCM to 1 per 2500 for the LQTS. SCD related to these diagnoses has been documented in infancy and during competitive athletics. In addition, prescription stimulant use for treatment of attention deficit hyperactivity disorder (ADHD) has been postulated to be a trigger for SCD.7,8 Sudden cardiac death in the young is a critical public health issue. A young life cut short represents a devastating event for families, and is associated with many lost productive years. There is significant dissonance among experts in the field about the best approach to prevent SCDY in the United States. Some experts support the implementation of largescale cardiovascular screening programs in infants, in athletes, or in all children to identify at-risk individuals in an effort to prevent SCDY. Cardiovascular screening for SCDY typically involves the addition of an ECG to the current standard of care of history and physical examination. Echocardiography and genetic testing represent alternative or additional screening modalities. Observational data from the Veneto region of Italy suggest that ECG screening can successfully identify at-risk cardiovascular diseases and dramatically reduce the incidence of SCD in competitive athletes.9,10 Proponents of ECG screening in the United States suggest that it can be effective, feasible, and cost-effective. 11 Critics of ECG screening cite a lack of evidence to support its effectiveness or feasibility in the United States; lack of clinical accuracy; cost implications; and the potential clinical, financial, and emotional consequences of falsepositive screening test results. 12 Cost estimates for a national ECG screening program in the United States for