Letter from the Editor

Playing with a Defibrillator = Playing with Fire?

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

A 23-year-old college football player survived an out-of-hospital cardiac arrest, and underwent implantation of a single-chamber transvenous defibrillator at another institution after being diagnosed with hypertrophic cardiomyopathy (HCM). He came to clinic for a second opinion after being advised not to continue playing football, hoping for clearance. Unfortunately, he was advised not to play.

There are several legitimate concerns about allowing a young man with HCM and a defibrillator to play football at the collegiate level. The first concern is that he has HCM. Are patients with HCM at increased risk of a cardiac arrest during extreme exertion? Although there is some controversy1, it seems likely. In fact, the basis of screening athletes is to identify those with high-risk cardiac disorders such as HCM. So, even if he did not have a defibrillator, he is putting himself at risk for another cardiac arrest. One could then argue that he now has a defibrillator and is protected from dying on the field. Although modern defibrillators are highly effective, how much evidence is there that his device will guarantee resuscitation during football practice? There is an interesting case report from 2005 of an athlete who suffered from commotio cordis, and despite immediate availability of an automatic external defibrillator, died from refractory ventricular fibrillation.2 The pathophysiology related to ventricular fibrillation may be different, but it is concerning. Finally, there are the fair questions about the risks of playing contact sports with a defibrillator. It is reasonable to be concerned about the effects of repetitive impact to the upper chest as well as forceful ipsilateral arm motions on the device and the lead.

Despite these concerns, some patients with a defibrillator, and their families, push hard to compete in sports and are either given permission to do so or participate against medical advice. Dr. Rachel Lampert and colleagues created a registry of such patients and recently published their long-term findings.3 There were 440 patients followed for a median of 44 months. The findings are presented as being reassuring: “There were no tachyarrhythmic deaths or externally resuscitated tachyarrhythmias during or after sports participation or injury resulting from arrhythmia-related syncope or shock during sports.” However, they go on to report that 10% of patients had an appropriate shock during sports, and that although twice as many patients had a shock during sports or other physical activity compared to being at rest (20% vs 10%), the likelihood of getting a shock during sports was the same as during other activities. This is not necessarily reassuring. How much time was spent being active? If an athlete averaged four hours every day playing their sport, which means they are inactive 20 hours per day, then the risk of a shock during activity is ten times as high as being at rest. Sports might be no riskier than other physical activities, but the data strongly support the concern that physical activity increases the risk of a shock. It is also important to note that although there were 440 patients, each sport and type of cardiac pathology was represented by very few patients. For example, only 65 patients had HCM, and only six patients were playing tackle football.4 In addition, it is worrisome that a shock might be less effective during exercise. Although the differences were not statistically significant, among all appropriate shock episodes occurring during sports, 23% required multiple shocks for termination versus 15% during other physical activity and 11% during rest (P=NS).

The authors acknowledge that there are limitations to their registry study, including that it was not randomized and that patients who chose to participate, or were permitted by their physicians to do so, were inherently at a lower risk. There is also evidence that for some cardiac substrates such as arrhythmogenic right ventricular cardiomyopathy, endurance training worsens the phenotype. However, the authors imply that, based on their data, electrophysiologists should now feel more comfortable letting a young patient with a defibrillator play competitive athletics. This registry is simply not enough to feel comfortable about that. There are too many logical reasons to be concerned, and the registry is not large enough with long enough follow-up to let most athletes with a defibrillator play sports. Imagine, for example, if a study were published showing that people who drink and drive have only a 1% risk of dying. Would we really tell people that it is okay to drink and drive? Patients who leave the hospital against medical advice are at increased risk of hospital readmission but have a 30-day mortality rate of <1%.5 Does that mean it is a good idea to leave AMA? Some things are just not a good idea.

The four-year data from this registry of athletes with a defibrillator is important, but when a patient with a defibrillator wants to play organized sports, particularly a patient with an arrhythmogenic cardiac substrate who wants to play a collegiate, high-intensity contact sport, let’s be very careful before we tell them it is okay.

References

  1. Atteya GA, Day SM, Lampert RJ. Sports and Exercise in Patients with Hypertrophic Cardiomyopathy: More Questions than Answers. ACC. Published February 23, 2017. Available online at http://bit.ly/2rMHjC0. Accessed June 18, 2017.
  2. Maron BJ, Wentzel DC, Zenovich AG, et al. Death in a young athlete due to commotio cordis despite prompt external defibrillation. Heart Rhythm. 2005;2(9):991-993. 
  3. Lampert R, Olshansky B, Heidbuchel H, et al. Safety of sports for athletes with implantable cardioverter-defibrillators. Long-term results of a prospective multinational registry. Circulation. 2017;135:2310-2312.
  4. Lampert R, Olshansky B, Heidbuchel H, et al. Safety of Sports for Athletes With Implantable Cardioverter-Defibrillators. Results of a Prospective, Multinational Registry. Circulation. 2013;127:2021-2030.
  5. Glasgow JM, Vaughn-Sarrazin M, Kaboli PJJ. Leaving against medical advice (AMA): Risk of 30-day mortality and hospital readmission. J Gen Intern Med. 2010;25(9):926-929.