Sudden cardiac death in a child is an uncommon but devastating occurrence. Using the primary and secondary prevention strategies discussed here, it can also be an avoidable one.
Because there is no national registry of pediatric SCD, the exact number of cases of unexplained SCD among children and adolescents in the United States is unknown, but a reasonable estimate is about 500 episodes a year.2 Each case of SCD provokes an emotional response and soul searching. Could this have been predicted? Could it have been prevented? In many cases, the answer to one or both of these questions is "Yes."
Most cases of pediatric sudden death are cardiac in nature, and every one is the result of an uncommon diagnosis (see Table 1). Causes of SCD can be grossly divided into structural-functional, primary electrical, and "other." In one study,3 hypertrophic cardiomyopathy accounted for approximately 36% of SCD cases. Anomalous origin of the left coronary artery from the right coronary cusp (with the coronary vessel coursing between the aorta and pulmonary artery) accounted for another 19%.3 Long QT syndrome affects one in 5,000 to 7,000 people and has increasingly been recognized in the pediatric age group.4 The "other" causes of SCD include commotio cordis and abuse of certain drugs and stimulants, such as ephedra and cocaine.
All of the conditions listed in Table 1 can lead to ventricular fibrillation. Many of the causes of SCD are genetic or familial, making investigation of the first affected family member critical for unraveling further familial involvement.
Primary prevention: Screening, treatment, awareness
The assessment form lists questions for the patient and family history that may reveal a risk of SCD. These questions are part of a comprehensive preparticipation athletic evaluation, but they are important for any active child. They should also be asked in the emergency room, especially when patients have been brought in with seizure, syncope, complex ventricular arrhythmia, or palpitations. Such an occasion may be the only opportunity to identify a patient or family member at risk of pediatric SCD and to refer for evaluation.
When obtaining a family history, make it thorough, document the source, and update that history periodically. Often, parents and children will not provide relevant information unless specifically asked. Nearly all Americans believe family health knowledge is important, but only one third of families have written a family medical history to share with their relatives.5 The US Surgeon General launched the family history initiative in November 2004; a computerized tool found at http://www.hhs.gov/familyhistory/download.html can aid in organizing a family history, especially during family gatherings.
Your physical examination of the patient may reveal abnormal blood pressure or pulses, a heart murmur, arrhythmia, or physical stigmata of Marfan syndrome. In patients with Loeys-Dietz syndrome, a familial form of heart disease that causes changes in the aorta similar to those of Marfan syndrome, the presence of a bifid uvula should raise suspicion of the diagnosis.6But many patients at risk of SCD do not have significant findings on physical exam. Close attention to the patient and family history is, therefore, key.
If you suspect a problem based on patient and family history or physical exam findings, refer the patient to a pediatric cardiologist with expertise in diagnosing and managing the uncommon cardiac disorders that cause SCD. Once a diagnosis is confirmed, antiarrhythmic drug therapy, family education, and activity restriction are possible. Newer cause-specific technologies such as radiofrequency ablation and the automatic implantable cardioverter defibrillator (AICD) are being used more often.7