There were no serious adverse events related to competition in a study of 129 young athletes with implantable cardioverter defibrillators (ICDs), providing reassurance that moderate-to-intense physical activity in this population may be safer than previously thought.
The new analysis—published Nov. 1 in Circulation: Arrhythmia and Electrophysiology—used data from the multinational ICD Sports Registry to examine the incidence of shocks during competition and monitor any serious adverse events related to arrhythmia. The primary endpoint of death, cardiac arrest or severe injury from shock or syncopal arrhythmia didn’t occur in any of the athletes during a median follow-up of 42 months. There were six total appropriate shocks recorded during competition or practice in four athletes.
“We show that many young athletes with ICDs can participate in competitive and high-intensity sports without failure to terminate arrhythmias or injury, despite the shocks, confirming results of a smaller single-center registry of 21 young people,” wrote lead author Elizabeth Vickers Saarel, MD, a pediatric cardiologist at Cleveland Clinic, and colleagues. “The rate of appropriate shocks during sports was low—1.5 per hundred person-years, and of the total shocks received, less than one-quarter occurred during sports. This suggests that restriction from this activity would not have a large impact on the overall burden of treated arrhythmias.”
The authors said sports participation in the ICD population should be based on a discussion between a physician, the athlete and parents.
A 2005 recommendation suggested athletes of all ages with ICDs only participate in class 1A competitive sports that require low cardiovascular output, such as golf, billiards or bowling, due to the perceived risks of physical exertion. But recent evidence suggests more intense sports can be safe in this population as well, although previous reports from the ICD Sports Registry included participants ranging from age 10 to 60.
For this subanalysis, Saarel et al. included only athletes ranging from age 10 to 21, with an average age of 16. Among the 129 participants, 79 participated in high school varsity or junior varsity sports, while 20 played collegiately. All participants competed in activities deemed more strenuous than class 1A, with basketball and soccer being the most common sports.
The most common cardiac diagnoses included long QT syndrome (49 patients), hypertrophic cardiomyopathy (30) and congenital heart disease (16).
Saarel and colleagues noted the shock rates and lead malfunction rates for the ICDs were similar to unselected pediatric populations. Twenty-nine appropriate shocks occurred during the study period, but only six happened during competition or practice, and there were no “adverse sequelae” in those cases, the authors reported.
Physical activity has many benefits for young people, including decreasing the risk for obesity, metabolic syndrome and future cardiovascular disease, along with boosting mental health.
The researchers found that among the 105 participants who stopped playing at least one sport during follow-up, 82 percent were for nonmedical reasons such as graduation. Only seven—or 6.7 percent of participants—stopped playing a sport due to an ICD shock and four of those athletes continued playing a different sport.
“These youth voted … and continued to play other sports, despite the risk—a strong testament to the perceived value of participation for these patients and their families,” Saarel and coauthors wrote.
Most participants had normal ventricular function, so the authors acknowledged the athletes could’ve been healthier than ICD patients who didn’t play sports or enroll in the study. And even though there were plenty of participants in “moderate-contact activities” like basketball and soccer, there were few who played full-contact sports such as football or rugby. Because of the low numbers for those sports, Saarel et al. cautioned the results shouldn’t be generalized to indicate the safety of those activities for people with ICDs.