ATLANTA — The resuscitation rate in athletes who experience sudden cardiac arrest as a result of ventricular fibrillation during sports events may be much better than widely assumed, Dr. Christine E. Lawless said at the annual meeting of the American College of Cardiology.
Sudden cardiac death in athletes on the playing field is a rare event, with an estimated 150–200 cases per year in the United States. As a result, there are almost no data on resuscitation success rates.
The widespread belief among physicians is that the resuscitation rate is low because of the severity of the underlying heart disease coupled with the intense catecholamine release during exercise, which is thought to raise the defibrillation threshold. But this assumption was contradicted by the personal experiences of physician members of the American Medical Society for Sports Medicine (AMSSM) in a new survey, according to Dr. Lawless, director of cardiac prevention, rehabilitation, and sports cardiology at Ohio State University, Columbus.
She received responses from 44% of the 1,069 AMSSM members to whom she mailed her survey concerning the use of external defibrillators to resuscitate athletes. Among those responses, 15 physicians described a total of 22 cases. The overall resuscitation rate with survival to hospital discharge was 14 of 22 (64%).
“That's comparable to what we see with AED [automated external defibrillator] studies in the general population,” she said.
The resuscitation rate was 71% in the 14 athletes who were older than 30 years, but only 50% in those aged 30 years or younger. The underlying cause of the cardiac arrest episodes differed by age, too. In patients up to age 30 years, the leading cause was cardiomyopathy, which accounted for 38% of cases; in older athletes, coronary artery disease was identified as the cause in 57% of cases, with the remainder being of unknown cause.
AEDs were employed in 12 cases, whereas manual external defibrillators requiring the operator to push a button to deliver the shock were used in 8 cases. One patient responded to a precordial thump, and one was treated first—unsuccessfully—with an AED followed by the application of a manual external defibrillator, which proved successful.
A recurring theme among survey respondents was frustration that when an athlete suddenly collapsed, the AED turned out to be locked in a training room located under the stadium.
“One of the things I advocate is that if there's an AED in the school, someone should routinely take it out of the training room and bring it over to the site of the practice,” Dr. Lawless said.
She added that in light of the favorable resuscitation rate highlighted in her survey, she believes an AED should be on the sidelines at every high-risk athletic event at all levels, including junior high school. High-risk activities include basketball, football, running sports, and sports in which commotio cordis is a risk, such as baseball and lacrosse.
Session moderator Dr. Douglas P. Zipes noted that selection bias is always an issue in a survey. He said he is aware of a soon-to-be-published small study which concluded—contrary to Dr. Lawless's findings—that the resuscitation rate in athletes is very low.
He added that he found her survey's finding that older athletes had a higher resuscitation rate to be both interesting and counterintuitive. “I would have armchaired the reverse: that younger patients have healthier hearts and would be more easily resuscitatable, but not so,” observed Dr. Zipes, director of the Krannert Institute of Cardiology at Indiana University, Indianapolis.
Dr. Lawless replied that her survey's finding is supported by the experience of medical directors of the big marathons.
“They tell me they bring back about 70% of older athletes [with cardiac arrest] and have much more trouble with the younger ones,” she said.