Sudden cardiac death in kids: What's the culprit?

Although sports have long been linked to sudden cardiac arrest in younger patients, a recent report reveals that obesity may actually play a larger role.

The study, published in Circulation, investigated cardiac arrest in individuals aged 5 to 34 years, reviewing circumstances around the event, resuscitation outcomes, clinical records, and autopsy results. Overall, the research team found that obesity was a factor in over 60% of sudden cardiac arrest cases in persons aged younger than 35 years.¹

Sumeet S. Chugh, MD, Price professor and associate director of the Heart Institute, and director of the Heart Rhythm Center, at Cedars-Sinai Smidt Heart Institute, Los Angeles, California, says the study demonstrates that obesity and other traditional cardiovascular risk factors may play a larger role in sudden cardiac arrest in young persons than previously thought.

“Efforts to reduce cardiovascular risk in the young are known to translate into reduction of adult cardiovascular disease burden, but these findings suggest that the benefit could extend to sudden cardiac arrest in younger age groups,” Chugh says.

The research team found that 5% of the nearly 4000 cases of sudden cardiac arrest studied occurred in the young, and that warning signs were present in only about a third of those cases. Sports was found to be a trigger in 39% of sudden cardiac arrest in patients aged 10 to 18 years, and 13% of cases in those aged 19 to 24 years. Shockable rhythms were found more often in sports-related sudden cardiac arrest, and survival was 2.5-fold higher in sports-related cases than in non–sports-related cases.

In sports-related sudden cardiac arrest, researchers found that more cases were witnessed—92% compared with just 40% of non–sports-related cardiac arrest. Warning signs occurred in only about 30% of sudden cardiac arrest cases overall, but were even less frequent in sports-related cases than in non–sports-related cases. In cases where warning signs were present, angina was the chief symptom in both sports-related and non–sports-related cardiac arrest. No particular sport was linked to sudden cardiac arrest over another, but males were more likely to experience sudden cardiac arrest whether in the sports or non–sports-related group, according to the report.

In terms of intervention, resuscitation was attempted in 82% of sudden cardiac arrest cases in youths, and 14% survived to discharge. Bystander cardiopulmonary resuscitation (CPR) occurred in less than half of the sudden cardiac arrest cases overall—42% in sports-related cases, and 32% in non–sports-related cases—and CPR by emergency medical personnel was performed in 100% of all sports-related cardiac arrests compared with 79% in non–sports-related cases, according to the study. Resuscitation efforts, as well as survival rates at discharge, were higher in sports-related cases than in non–sports-related cases, the research team found, with 28% of sports-related cases surviving to discharge compared with just 11% of non–sports-related cases.

In all cases of sudden cardiac arrest, researchers were able to identify some common causes—31% of cases were attributed to sudden arrhythmic death syndrome; 22% to coronary artery disease; and 14% to hypertrophic cardiomyopathy. The research team also concluded that the “unexpectedly high” prevalence of classic cardiovascular risk factors in cases of sudden cardiac arrest in youths suggests there may be cause for a greater focus on risk stratification at younger ages. There is still more work to be done, however, to find the best ways to identify cardiovascular risk in children.

“Since the majority of cases did not experience warning symptoms, significantly more work is needed to improve the sudden cardiac arrest risk stratification process in the younger population,” Chugh says.

Chugh adds that despite the study finding of sports as a potential trigger of cardiac arrest in the young, the overall frequency was low at just 14% of all sudden cardiac arrests in individuals aged younger than 35 years. More research is needed before the study findings should be used to justify widespread routine screenings, he notes. Instead, Chugh says he hopes the report will generate more interest in uncovering causative and risk factors for cardiovascular problems in the young.

“We hope that it will focus attention on the more common and rapidly rising contributors to risk of sudden death in the young. We generally expect risk factors such as diabetes, obesity, hyperlipidemia, and smoking to create problems for older populations,” Chugh says. “In this regard, the high rates of these factors among young individuals who experienced sudden cardiac arrest came as a surprise. More research is needed to understand prevalence of these risk factors among the general population in this age group before we can deploy specific plans for screening and prevention.”