Because most cases of sudden cardiac death in young athletes stem from an underlying heart condition, a child's sudden death or resuscitation from cardiac arrest should always prompt medical evaluation for the whole family, starting with parents and siblings and, possibly, extending to other family members.
"Because several types of inherited, and often lethal, heart conditions can manifest themselves in sudden death or fainting during exercise, the story doesn't end with the child being successfully brought back to life or with the postmortem results," says pediatric cardiologist Anne Murphy, M.D., of Hopkins Children's.
Once the initial shock is over, the family should talk with their physician about further evaluation to rule out inherited forms of heart disease, she advises.
Who should be tested and when?
Pediatricians should refer to a pediatric cardiologist any child with chest pain and/or fainting that occur during exercise. Tests may include an electrocardiogram (ECG) and an echocardiogram. An ECG captures the electrical activity of the heart and can reveal some abnormalities that can cause fatal arrhythmias. Most people with such conditions have normal heart structure. The echocardiogram, on the other hand, uses ultrasound to check for abnormalities of the heart's structure, including any thickening of the heart muscle, called hypertrophic cardiomyopathy, the top killer in young athletes who die from heart disease.
Any child with a family history of sudden cardiac death not caused by common types of coronary heart disease that occurred in a parent or sibling should see a pediatric cardiologist. Referral is a good idea even if an autopsy was never performed, or if the postmortem exam didn't find a clear cause of death, Hopkins Children's experts say. Most people who die of heart-rhythm disorders have structurally normal hearts, and the autopsy is often unrevealing, Murphy explains. Any children with family members who develop coronary heart disease before age 50 should have a cholesterol check at a minimum. If the test shows unusually high levels, the child should undergo further evaluation for inherited cholesterol disorders, Murphy adds.
Genetic testing: To do or not to do?
Genetic testing can identify the genetic mutations behind some types of inherited heart disease. People with symptoms suggestive of such conditions are good candidates for genetic testing as are their symptom-free family members. Testing the rest of the family can help cardiologists determine who needs therapy, lifestyle changes and close clinical monitoring to ward off sudden cardiac events in the future, Murphy says. A negative test can be reassuring, and a positive test can lead to lifesaving treatment with medication or an implantable defibrillator.
However, experts warn, genetic testing has its own pitfalls and needs to be done only in the context of a full clinical evaluation along with thorough genetic counseling.
"Genetic tests should never be the first step in evaluating a patient," Murphy says. "They should come last to confirm a suspected diagnosis, and only once the cardiologist has specific genetic test targets in mind."
There are two important caveats, cardiologists warn. Because multiple genes are tested, there's always a chance to detect a variation, but a variation doesn't always mean disease, nor will it necessarily explain certain symptoms. In such cases, clinical evaluation and family history become even more important, Murphy says. On the flip side, genetic tests may not detect any mutation in some people with clear signs of heart disease, but that doesn't mean they don't have a disorder.
"All it means is we have not found the genetic mutation responsible for their symptoms," Murphy says. This is why a session with a genetic counselor before the test is critical, experts say.
"We must prepare patients for the possible outcomes of the test," Murphy says, "and what they mean to them."
Source: Johns Hopkins University