Short-Term and Long-Term Injury to the Heart with Exercise

In my column this month at Endurance Corner, I write about the potential harm to the heart that might result from exercise. We've known for a long while about the many beneficial effects of exercise, but investigators are just beginning to learn about the potential for short- and long-term adverse consequences on the heart.

I'm sure there will be more to come on this issue.

Cardiac Arrest During Long-Distance Running Races: A New Report

This past week, the results from an important study on the heart risks of long-distance running was reported in the New England Journal of Medicine.

A group of investigators from Boston looked at the experience of ~11 million runners who took part in half marathon or full marathon races in the United States between 2000 and 2010. This is the largest study of its kind ever undertaken.

The important findings were:

-59 athletes had cardiac arrest and 42 of those died

-For marathon runners the risk of cardiac arrest was 1.01 per 100,000 participants

-For half marathon runners the risk of cardiac arrest was 0.27 per 100,000 participants

-The risk for men was several-fold greater than for women

-The majority of deaths occurred during the last 6 miles of the marathon or the last 3 miles of the half marathon

-From medical records, the cause of cardiac arrest could be determined for 31 victims (23 of whom died). In most of the cases where the athlete died, there was a specific heart condition that was responsible:

---Hypertrophic cardiomyopathy (HOCM) in 8

---Possible HOCM in 7

---Hyperthermia in 1

---Arrhythmogenic right ventricular cardiomyopathy in 1

---Hyponatremia in 2

---No specific cause in 4

Some important, NEW observations were:

--The frequency of cardiac arrest is extremely low....and even lower than previously thought.

--The survival rate from cardiac arrest was surprisingly good, at 29%. This is much higher than previous reports for out-of-hospital cardiac arrest. It suggests that bystander CPR and early defibrillation may be readily available at race venues.

--The risk is greater in marathons, compared to half marathons. The reason(s) are not yet clear.

This new report provides the most comprehensive information yet on cardiac arrest during running races. Athletes should be encouraged by the extremely low rate of cardiac arrest and with the favorable survival rates reported. Athletes should also take note that the cause of cardiac arrest was most often due to an underlying cardiac condition that might be discoverable BEFORE participating in a traning program or race. It's reasonable to conclude that a pre-participation visit to the doctor for a careful physical examination and, potentially, cardiac testing might reduce an athlete's chances of being a victim.

Race Safety and USA Triathlon

I had the chance to attend the annual USA Triathlon Race Director's Symposium this weekend in Colorado Springs.

Along with Stuart Weiss, MD (medical director of the ING NY Marathon. NY City Triathlon, and upcoming Ironman New York triathlon), Richard Miller, MD (a trauma surgeon at Vanderbilt University), Bob Burnett (a New England race director), and Robert Vigorito (a mid-Atlantic race director), I'm serving on a Medical Review Panel convened by USAT to review the experience with race-related fatalities over the past decade and to offer recommendations about improving race safety going forward.

We've had a chance to review preliminary information about race-related fatalities from 2003-2011 and I was asked to present some information to about 80 race directors from across the country who were attending the Symposium.


Some Preliminary Information about Triathlon Fatalities

A snapshot of event-related fatalities at USAT-sanctioned events:
-44 athlete fatalities, including 5 traumatic deaths and 39 non-traumatic deaths
-All 5 traumatic deaths occured with bicycle crashes
-Most (and, conceivably all) of the non-traumatic deaths were due to sudden cardiac death (SCD)
-The majority of the non-traumatic deaths occurred in the swim leg of a race, but there were also deaths in the bicycle and running legs....and 2 deaths that occurred after athletes had completed a race and left the race venue
-Deaths occurred in athletes in nearly every age group
-Deaths occurred in races of every distance from short sprint to Ironman distance


Some Information about Sudden Cardiac Death (SCD)

I shared some general information about SCD, describing reports from 2011 on NCAA athletes and on the French general population:

-In NCAA athletes, the incidence of SCD is 1 per 43,770 athletes per year
-Basketball and swimming appear to have the highest risk

-In the French general population, the risk of SCD is 4.6 cases per 1,000,000 population per year
-Deaths were noted in nearly every conceivable sporting activity
-Deaths were noted in individuals from 11 years old to 70+ years old
-Extrapolated to the U.S. population, there should be 4000+ fatalities in the U.S. due to SCD each year


Feedback from the Attendees

I had a chance to hear from the race director attendees about many relevant experiences. Indeed, several of the race directors who were present had firsthand knowledge about some of the fatalities.

Race directors from Utah were able to share with the audience their approach to dealing with the aftermath of such a fatality--from sharing information at the race venue, to working with family members of the victim, to working with the medical and EMS crews who attended to the victim.

There were many suggestions about how we might work to reduce the number of fatalities:

-Easier access to AED's, including deploying an AED on a boat so that CPR and defibrillation might occur earlier in the event of a swim leg event
-Reducing anxiety among swimmers before the race. Attendees noted that the NYC Triathlon already employs psychologists to conduct pre-race briefings where coping strategies are discussed
-Wearing inflatable devices during a swim which could be deployed if/when a swimmer experienced difficulties
-Designing swim courses to limit the distance from shore
-Having pre-established action plans for the specific possibility of SCD during the swim


One particularly heart-warming story came from a young race director who shared his personal story of having SCD at the swimming pool in 2010, receiving 14 minutes of CPR, and being resuscitated successfully. He now has an internal defibrillator and is working through the issues of how active he can continue to be. He's continuing his passion for triathlon by serving now as a race director.


A Visit to USAT's Offices

On the last evening of the Symposium, we visited the offices of USAT for supper and some fellowship. I was totally fascinated by the many photographs and memorabilia on the walls of the office. The highlights were photographs of the Olympic triathlon teams from the 2000, 2004, and 2008 Olympic Games. Really inspiring.


Ahead



Our Review Panel's work will continue in the coming weeks as we work to understand more about the athletes who died and about the circumstances surrounding their deaths. I'm optimistic that when we're finished with our review, we'll be able to offer some useful advice to USAT and some information to the endurance sport community at large. I'll keep you posted.

I'd be happy to receive comments and suggestions from the readers here about how we might improve race safety.

Cardiacathletes.com: An Online Patient Support Community

I've been aware of an online patient support community called Cardiac Athletes for a while now. I got an email yesterday from Lars Andrews, their chief cardiac physiologist asking if I'd spread the word about their site.

Taking a look, the site brings together athletes from around the world with various heart conditions. There is some general information that will be useful to athlete patients, but the biggest opportunity here is the Forum, where athletes can connect with each other about their medical conditions.

So check out www.cardiacathletes.com.