SAN DIEGO – Pediatricians should screen patients for hypertrophic cardiomyopathy if a first- or second-degree relative has been diagnosed with the condition or has a history of sudden death, said Dr. Kevin Shannon, a pediatric cardiologist at the University of California, Los Angeles, Medical Center.
“Anybody with a family history of HCM, including uncles, cousins, parents, and siblings, should be screened,” he emphasized. “Even if they don’t have obstructive HCM, they will often have a murmur, most commonly at the upper sternal border.” The murmur is typically late-peaking and worsens during Valsalva, he added.
HCM is the most common cause of sudden death in athletes and is the most common genetic cardiac disease, affecting about 1 in 500 young adults (Circulation 1995;92:785-9). The autosomal dominant inheritance pattern shows varying degrees of penetrance, translating to a range of phenotypes, Dr. Shannon said at the annual meeting of the American Academy of Pediatrics. “Even if your family member didn’t have hypertrophy until age 30, you can get it at age 5, and the opposite can also be true,” he noted.
HCM can be a silent disease until it causes sudden death. However, pediatricians should ask patients about exercise tolerance and should consider HCM in patients who describe a substantial drop in sports performance, Dr. Shannon said. An athlete with HCM might say that he or she always finished the field lap first and is now second to last, and a soccer player with a field position might say, “Now I finish the runs after the goalies,” he said.
A resting electrocardiogram is not sufficient to exclude HCM, Dr. Shannon emphasized. Because up to 10% of patients with HCM have normal ECGs, children whose parents or grandparents have HCM should have an echocardiogram every 5 years until puberty, and then every year until they turn 20 years old or finish growing, he said. But ECGs also are important because they may become abnormal before the echocardiogram does, Dr. Shannon said. If the ECG becomes abnormal, pediatricians should tell parents that the echocardiogram is likely to become abnormal and should advise them to steer the child away from competitive athletics, he said.
Twenty-four hour ambulatory (Holter) ECGs also are part of risk stratification in patients with HCM, Dr. Shannon said. The American College of Cardiology and the American Heart Association recommend Holter monitoring for the initial evaluation of patients with HCM and for patients with HCM who develop palpitations or lightheadedness (J. Am. Coll. Cardiol. 2011;58:2703-38).
Dr. Shannon reported no conflicts of interest.