Often times, there are no warning signs prior to a SCA/SCD. Many individuals who experience SCA/SCD, however, report experiencing symptoms, such as fainting, before the actual cardiac event. Family history can be an important warning sign as about 40 percent of people experiencing a SCA/SCD report a family history of heart disease and about one in four individuals report a family history of SCD before age 50.
Sports activity has been linked with an increased risk of SCA and SCD in individuals with personal or family risk factors. Recommendations for screening in athletes were published initially in 1996 and have been reviewed and updated. The 12 Element AHA Recommendations for screening include the presence of early death before age 50 years due to heart disease in a relative and a known diagnosis of heart disease in a close relative younger than 50 years of age. The degree of relation to the person in the family with heart disease is important. The closer the relation, the greater the potential for risk of SCA and SCD. Athletes with potential increased risk based on the AHA Recommendations should be referred for further evaluation. For non-athletes, routine well-child visits are the standard of care in the United States. However, current recommendations for screening for SCA and SCD are not well defined. It is important to share your family history of heart disease or SCA/SCD with your child’s doctor.
The evaluation of family members, when a SCA/D occurs, should proceed in a logical and stepwise fashion. A detailed family history is important and information must be gathered from available medical records or post-mortem examinations to determine the cause of death. In some cases, the cause of death remains unknown. In this case, a more complete heart evaluation with echocardiogram, electrocardiogram, and lipid screening may be indicated. In addition to confirming the cause of sudden death in the family, the degree of relation to the deceased individual is important. Further evaluation is most often indicated for first-degree relatives (parents, siblings and children). While families are often anxious and worried after a SCA/SCD, recommending and receiving normal heart testing results may provide false reassurance if the cause of death is not known. If a heritable cause for SCA/D is likely then it may be wise to involve genetic counseling as a first step in risk assessment.
Identifying the cause of SCA/D is important and necessary in order to provide accurate information to family members. In the case of SCD, ensuring that the medical examiner obtains and stores a sample available for genetic testing is important. One barrier to postmortem genetic testing has been lack of an available blood sample on the deceased individual.
If the cause of SCD is confirmed, either because of known heart disease before the SCD event or post-mortem diagnosis, genetic testing should be performed based on the specific diagnosis. If a genetic cause is found, family specific testing should be offered to relatives. Clinical genetic testing is available for a number of heart diseases associated with an increased risk for SCA/D. Initiating genetic testing in an unaffected individual is typically not recommended as the result interpretation is difficult and results are unlikely to be helpful in diagnosis, risk assessment and management.
Postmortem genetic testing can be helpful in cases of sudden unexplained death. In cases of sudden unexplained death with normal autopsy, postmortem genetic testing may reveal a cause of death in approximately one in four cases. Long QT syndrome (LQTS) and another inherited arrhythmia, catecholaminergic polymorphic ventricular tachycardia (CPVT), are the most common genetic causes of sudden unexplained death. Both LQTS and CPVT demonstrate autosomal dominant inheritance, thus 50 percent of the relatives may have inherited the identified gene mutation and yet may have normal cardiac testing. Another major function of such testing is reassurance of relatives who did not inherit the disease-causing mutation and avoidance of unnecessary screening and treatment.