Newswise — With fewer than 3,500 episodes a year, cardiac arrest in children is decidedly rare, but it could be a dramatic signal that the victim’s family members may be at a heightened risk for sudden cardiac death.
This is why, in the aftermath of such a traumatic event, clinical evaluation of the child’s parents and siblings could lead to lifesaving diagnoses and therapies, averting further tragedy, say cardiologists at Ann & Robert H. Lurie Children’s Hospital of Chicago.
“When a child dies suddenly from heart disease it’s a tragedy. Our goal is to prevent the even greater disaster that can occur if another family member has a similar event,” says pediatric cardiologist Gregory Webster, MD, MPH, director of the electrocardiogram laboratories at Lurie Children’s and assistant professor of pediatrics at Northwestern University Feinberg School of Medicine. “The goal is to identify who else in the family might be at risk and offer treatments to prevent or reduce the risk of sudden death for them,” Webster adds.
A family screening should be performed even if a child’s autopsy reveals a structurally normal heart, the Lurie Children’s experts say. This is because many cardiac arrests can be triggered by a failure in the heart’s electrical-signaling system rather than by the heart muscle or the structure of the heart.Cardiac arrest — a condition in which the heart suddenly stops beating or starts quivering chaotically — most commonly stems from several types of inherited heart disease. These include certain defects in the heart’s electrical system that can spark fatal arrhythmias, abnormalities of the heart muscle itself, or defects in the structure of the heart’s arteries or valves.
Who should get screened for heart disease?• All first-degree relatives — parents and siblings — of children who suffer sudden cardiac arrest or die suddenly and the cause of death remains unclear
• Anyone with a first-degree relative who died suddenly before age 35 and the cause of death was not determined or there was suspicion it might have stemmed from a heart problem
• All children who engage in sports should have a routine pre-participation physical exam with their pediatrician and families should discuss family history with the physician at that time
Screening and diagnostic tests
Family members of children who suffer cardiac arrest should be screened by an expert familiar with inherited causes of sudden death. This evaluation typically includes a physical exam and detailed family history, followed by several common heart function tests. While every case and every scenario will require an individualized and tailored testing, these are some of the more common tests used to evaluate risk among family members of someone who has suffered a cardiac arrest or sudden cardiac death:
• An electrocardiogram (ECG) that briefly traces the heart’s rhythm and can also detect certain anatomic abnormalities, such as heart muscle thickening
• An echocardiogram — an ultrasound of the heart — that visualizes the size and function of the heart muscle and the anatomy of key heart structures
• An exercise stress test that captures how the heart responds to physical exertion
Based on the findings of these tests, some people may need further genetic work-up.
Genetic testing: Who, when and how?A genetic test can be considered in people with family history of sudden cardiac death but is by no means a silver bullet and should not be the first step in the evaluation, Lurie Children’s cardiologists say. It should be done as the final step, following a physical exam, a detailed family history and clinical tests.
“Genetic testing is becoming more sophisticated every year, but it still needs to be ordered and interpreted in the context of family-specific circumstances and findings,” Webster cautions. “Genetic testing helps clarify why sudden death may have occurred, but is not a substitute for a careful, thoughtful clinical evaluation.”
This is because current genetic tests, even though increasingly sophisticated, provide a reliable clue only 45 percent of the time, Webster says. In other words, a negative genetic test doesn’t necessarily rule out inherited forms of heart disease, nor does a positive result always portend clinical disease.
“We’ve made great strides in our ability to diagnose genetic aberrations, but our tools are far from perfect,” Webster says. “Interpreting the results of a genetic test should be done carefully by a pediatric and a genetic counselor with training in familial heart disease.”
Treatment for those determined to be at high risk depends on the specific findings from the clinical evaluation and the genetic testing. In many cases, certain medications can help reduce the risk of cardiac arrest. For those at extremely high risk for cardiac arrest due to dangerous rhythm disturbances, an implantable cardioverter-defibrillator can be used to shock the heart back into normal rhythm.
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