Feature: Marathon runners not immune to sudden cardiac arrest
Each year, between Hopkinton, Mass. and Boston, more than 20,000 runners pack the streets to complete the 26.2-mile Boston marathon course. But, what happens when a cardiac event takes place?

Medical volunteers from eight towns and 10 hospitals—a total of 1,400 staff—man 26 medical tents strategically located along the course in case a medical event occurs. And with recent data outlining the increased risk of sudden cardiac arrest and sudden cardiac death (SCD) in athletes, particularly marathon runners, the push for automatic external defibrillators (AEDs) has become more prevalent.

“A lot of runners become either ill or injured on the course and we want to make sure that we respond to an injured runner in the 26.2 mile course in four minutes or less,” Chris Troyanos, Boston Marathon medical coordinator and director of sports medicine at Lasell College in Newton, Mass., told Cardiovascular Business during an interview.

“Obviously if we do have a cardiac arrest of some type we can start immediate CPR, but within a 26.2 mile course this can be a very challenging feat.”

Four to six minutes after cardiac arrest, brain death begins and as every minute passes a patient’s chance of survival decreases 7 to 10 percent. Ninety-five percent of these patients die before reaching the hospital; however, when defibrillation is administered within five to seven minutes, the survival rate climbs to 49 percent.

A recent study published in the British Journal of Sports Medicine looked at the prevalence of sudden cardiac arrest (SCA) in marathon runners. Webner et al found that of 1,411,482 runners who participated in marathons between 1976 through 2009, 31 SCAs resulted in 11 deaths. In other words, the prevalence of SCA was one in 45,531 and one  in 128,316 runners died.

At this year’s marathon on April 18, Philips Healthcare loaned 40 HeartStart AEDs and 30 HeartStart MRx monitors to the medical staff; this loan had an attached price tag that totaled almost $700,000.

Troyanos said the goal is to treat SCA patients within four minutes of an event. “If you go into cardiac arrest the longer it takes to start immediate life-saving measures the less chance a patient has of surviving. Once you go beyond that four-minute golden window it’s more difficult to bring someone back.”

And while the Boston Marathon is a major sporting event, he said it’s planned for the same way a mass causality event is planned for.

“We know that on any given day, regardless of the weather, we will have a certain percentage of runners that will need medical care,” Troyanos offered. This year at least 1,100 patients were treated at the finish line. “If you look at the definition of a planned mass causality event, this was it.”

While there were no incidence of SCD this year, Troyanos said there was one case where an MRx monitor was used to cardiovert a patient who was experiencing an MI. However, because the response was so quick, the patient made it to the hospital in time.

While Troyanos said that marathon running is a relatively safe sport, the numbers of runners participating is at an all time high, and so is the incidence rate of cardiac arrest.

He said that 10 cardiac arrests occurred during marathons that took place across the country in 2010.

“So what we are saying is by being prepared and having the right equipment often times you will be able to resuscitate the patient and bring them back,” said Troyanos.

Troyanos said that one of the most difficult aspects of  providing medical treatment to marathon runners is the fact that medical teams have no prior medical histories, which makes it difficult to understand what the current event could be related to.

If the industry began asking runners more specific questions about medical history, Troyanos said that this would enhance patient care. However, the big question will be: if a patient has a history of cardiac arrest or family history of cardiac arrest, should they participate?

A few points seem clear--a medical history could help responders facilitate care to stricken athletes, and strategic placement of AEDs can accelerate treatment and save lives.