Screening for SADS Conditions
SADS Foundation Statement on ECG Screening
SADS Medical Education Committee, 3/10/2020
Background: Each year, several thousand infants, children and young adults/adolescents die suddenly and unexpectedly. The SADS-related genetic heart diseases such as Long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and Brugada syndrome (BrS) are some of the causes for sudden death. Sudden death related to these conditions may be preventable if at risk patients are identified. Screening for these inherited conditions is fully supported by the SADS foundation. Details of this screening (who, when, how, and how often) continues to be controversial, as there is no universally accepted protocol. Patient specific screening should be based on history and clinical presentation. This statement will take us through some of the controversies surrounding sudden death screening and SADS current position.
Who to Screen: There are many different philosophies on screening, yet no one system has proven to detect all patients who are at risk for sudden death. Approaches differ across the globe. Who to screen should not be dependent upon geography, socioeconomic background, or access medical experts familiar with the SADS conditions. Mass screenings such as those adopted in Italy or Israel may not be feasible in countries like the United States. For example, in Italy, all newborns are screened for Long QT syndrome with an ECG. In the US, children and young adults participating in organized athletics are screened via a pre-participation evaluation consisting of a physical examination and directed questions to stratify patients at risk for sudden death. Additional testing such as ECGs or echocardiograms are performed only if indicated.
How to Screen: Just as who to screen remains a controversy, how to screen these patients can be even more challenging. Though non-invasive testing such as ECGs, echocardiograms, external rhythm monitoring and exercise testing may enhance the sensitivity of screening, these come with a significant burden. There are logical, technical, and financial challenges to performing comprehensive mass screenings in a center where the tests can be performed properly and interpreted by trained clinicians. But, choosing only one test or two tests (such as echo and ECG) may not even identify certain conditions (CPVT). Just as important, false positives can lead to significant psychological sequelae and dramatic changes in quality of life (unnecessary restrictions for athletics). Additionally, validated normals for these tests for all patients based on gender, race and body shape size are not currently available leading to the possibility of underdiagnosing patients who are truly affected by the cardiac disorder or false positives. Finally, though genetic testing is available for many conditions, not all disease causing mutations have been discovered. Variants of certain genes can lead to more questions and may not provide a diagnosis. Genetic testing is only recommended with a high suspicion of the disease and not as baseline testing.
How often to screen: As with many conditions, the phenotypic expression of the disease can change with time or a clinical scenario. One-time screening is not enough as some of these conditions can be progressive, or may not be evident on a one-time test. For example, patients with Long QT syndrome can have normal QT intervals on an isolated ECG. CPVT, usually evident only during exercise, has a normal resting ECG, leading to potential underdiagnosis of a potentially life threatening condition. Timing or frequency of screening for sudden death has not been validated and therefore there is not a consensus on when to start or when to repeat such testing. The SADS Foundation does not support the use of one-time mass screening for these reasons.
What happens if a screening is positive: If testing suggests the potential for a SADS condition, follow up with a cardiologist who is experienced in managing SADS related diseases is recommended. The SADS Foundation is committed to being a patient/family advocate and can help find a center with a cardiologist who is an expert in SADS conditions. The SADS physician referral network has identified recommended centers across the United States. Other sources for experts are the Heart Rhythm Society (HRS) as well as the Pediatric and Congenital Electrophysiology Society (PACES).
Conclusion: Individuals at risk for sudden death need to be identified. This is not limited to the inherited or acquired SADS conditions. Therefore, SADS fully supports efforts that strive to create public safety measures to protect our entire community. We will continue to actively participate in the conversation and support research pertaining to SADS -related conditions. As a patient advocate organization that is based on evidence based medicine, the SADS Foundation will continue to work towards developing a screening system that works to prevent sudden death, for all patients. But, because there is no “perfect” screen, the SADS Foundation and its medical partners will continue to support secondary prevention of sudden death by implementing training/preparation for schools (emergency action plans) and the presence of automatic external defibrillators (AED) in public spaces.