Can You Exercise with an Implantable Cardioverter Defibrillator (ICD)?

Podcast Transcript

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Mohamed Kanj, MD:

Thank you for the opportunity to participate. I'm going to try to summarize the talk and, hopefully, by the end of the talk you'll understand why I'm doing so. The first message I want to deliver is the underlying disease and not the ICD should be the principal factor for the decision on sports participation. Meaning, if they're safe to exercise with an ICD, they're safe to exercise without an ICD. And if they're not safe to exercise without an ICD, they're safe to exercise with an ICD. So, the ICD should not be a deterrent or a reason for them to exercise.

Message number two is that when you make a decision about participation in patients who have an ICD, consider the impact of the event on the disease, the patient, the co-team players, the spectators, as well as the ICD itself. And message number three is that the ICD should not be placed solely to allow for sports participation. We used to think in the past that patients with ICD were recommended not to participate in regular sports, low dynamic, low static activities like bowling or golf. This was due to the concern that ICD may not defibrillate at peak exercise, concern that aggressive exercise may accelerate the primary disease, concern that a bad event may result in significant injury to the patient or spectators in case there was altered consciousness, and lastly, because of the concern that exercise may result in damage of the ICD system itself.

However, restrictions from sports also have a significant downside. It's well known that sports have significant psychological as well as physiological benefits. Restrictions from sports for any reason have been shown to decrease both the physical and emotional quality of life of our athletes. And for many adolescents with ICDs, restrictions from sport were the biggest factor impacting their quality of life.

Also, there's also a concern that when we restrict them from exercise, we can contribute to worsening the disease by causing obesity, hypertension, sleep apnea, and diabetes. And there are some people who simply say, "Hey, I don't care. I'm happy to take that extra risk. I want to participate in exercise." So, why are we concerned about arrhythmia and exercise? In the general population, the paradox of exercise is well described. What do I mean by that? Sudden cardiac death is less common in those who exercise vigorously. However, the risk of an event is higher during exercise. While often considered a paradox, this is likely explained by the role of autonomic nervous system in arrhythmia generation. Catecholamine, for example, is known to promote arrhythmia and there is the highest levels when patients are vigorously exercising.

So, let's go over specific conditions with exercise. Okay. First, we'll talk about ARVC. What we know is that during exercise, they get more and more arrhythmias. But what we also know is that ICDs are effective in terminating these arrhythmias even during exercise. However, what we know is that sometimes these guys, when they go exercise, they have ventricular storm, which is very concerning. And we're also concerned that high-level exercise may accelerate the cardiomyopathy progression in these patients. Thus, competitive sports should be discouraged in this group of patients, even with an ICD.

If we look at the other form of dilated cardiomyopathy, also exercise is arrhythmogenic, but fortunately, ICDs do work. But we do have concern also in this population that exercise can also accelerate the disease progression, and thus patients are not usually recommended to participate in competitive sports. What about hypertrophic cardiomyopathy? We know ICDs seems to be effective in aborting sudden cardiac death in this group of patients. However, we have to be careful because these patients usually have the highest defibrillation threshold, and thus defibrillation testing is very reasonable in this patient group. And probably, if you want to let them exercise, discourage them from doing competitive exercise, but I think it is very reasonable to do mild to moderate exercise. You have to make sure that the defibrillator works before you do anything. And there's some data suggesting that moderate exercise in sedentary hypertrophic cardiomyopathy does have a positive impact, improves physical conditioning without causing significant arrhythmias.

What about CPVT? CPVT is unique in that the ICD is not nearly as successful in converting arrhythmia as it is in other arrhythmogenic conditions. In fact, ICD shocks increase catecholamine and make people more prone to further arrhythmias. In a group of around 15 patients who've had an ICD, six people were treated for ventricular arrhythmia, but unfortunately, two of them ended up dying from VTA refractory to ICD therapy. Because these patients can get a VT after a VT, after a VT, and the pain and discomfort can cause more and more VT. Thus, again, in this patient group, it's not advisable, even if they have ICD, to participate in competitive sports. And usually, before they start any kind of sports, these guys need to have a stress test to make sure that they don't have any arrhythmia at that level of exercise that they're interested in.

What about Long QT? We know that sudden cardiac death can occur during exercise, but we also know that ICD does work in this patient group. And so, under certain settings, it may be allowed for them to do some exercise.

What about coronary disease with ICD? I think these guys can participate in exercise as long as there's absence of critical coronary artery stenosis and a negative stress test at maximum capacity showing no ischemia, no ventricular arrhythmia, and normal exercise capacity.

What about the sport itself? Can we allow them to participate in one sport versus another sport? Usually, violent contact sports are discouraged, like American football and hockey, because we're worried about the ICD itself. Also, arrhythmias may cause temporary loss of consciousness, subjecting individuals to harm themselves as well as to others. Thus, for example, I discouraged them from diving, mountain climbing, cycling, racing, all of these things that could injure them and other people in case they lost consciousness.

Our first reported experience with safety and efficacy of ICDs in athletes was reported in 2013. I looked at the ICD registry, and there were around 372 patients. Sixty of them were participating in competitive sports, including running and soccer, and nearly half of them had their ICD due to ventricular tachycardia and ventricular fibrillation. During a 31-month follow-up, there were no reported death or resuscitation arrest during the sports. However, there were 10 percent ICD shocks during competition and another 8 percent during physical activity. Both appropriate and inappropriate shocks were common during exercise and competition. And the only predictor for appropriate shocks were younger age; teenagers seem to get more shocks, as well as certain disease conditions like ARVC, CPVT, and idiopathic ventricular fibrillation. They were at a higher risk of developing ICD shocks. In 2017, another 440 athlete registries with ICDs, aged between 10 and 60, two-thirds of them were men, and nearly half of them had history of ventricular arrhythmias, chose to continue competing in sports, and they were prospectively followed. The most common cardiac conditions for this registry were Long QT, hypertrophic cardiomyopathy, and coronary heart disease. And the most common sports that they participated in were running, soccer and basketball. But 20 patients among this study continued to participate in high-level competitive sports at university level, and there was participating with soccer, I think, basketball, lacrosse, and others. When you look at this data, there was no history of failure of ICD to defibrillate. So, that's reassuring. Nobody had to do external resuscitation. So also, that's reassuring. There were no injuries during syncope arrhythmia, so that's reassuring. 10 percent of them end up with an ICD shock, and that's around 3 percent per year. While more athletes received shocks during some form of physical activity than during rest, there was no difference between competition and just regular physical activity. Unfortunately, however, the occurrence of ICD shocks was associated with significant increase in psychological distress in both the patients as well as the families.

We know from past studies that patients who have received shock have worse quality of life compared to those who don't get a shock. While a third of these athletes who receive shock during sports stopped playing, two-thirds of them end up coming back to exercise. So, that's just that there is significant beneficial impact of sports participation and qualities of life, and that outweighed the negative impact of shock in most of these athletes.

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