Introduction
As a result of suffering from, or being at risk from, serious heart rhythm disturbances (arrhythmia), you have been fitted with an Implantable Cardioverter Defibrillator or ICD. One of the most important reasons for you having this device is to keep you as healthy, active and independent as possible.
Your cardiologist, arrhythmia/ICD nurse and/or cardiac physiologists will have given you information regarding how the device works, what to do if it goes off and should have advised you regarding matters such as driving and equipment that may interfere with your device. Please see also our ICD patient information booklet.
A question that often does not come up for a while after the ICD is fitted, however, is “can I take exercise, and if so, how much and what sort?”
Is it safe to exercise?
The simple answer to this question is yes, but the full answer is influenced by the cause and type of your arrhythmia and the type of exercise you perform.
The likelihood of arrhythmia during exercise is very small but when it occurs it is sometimes linked to an abnormality of heart function and not the presence of an ICD. This is especially true if you have suffered considerable damage to your heart as a result of a heart attack myocardial infarction or have a
heart muscle disease cardiomyopathy.
The likelihood of arrhythmia is no greater during moderate intensity aerobic exercise than during resting but there are certain types of exercise that increase the risk of arrhythmias. If you exercise hard, from rest, without a warm-up and immediately cease exercise, without a cool down or active recovery period, you increase the likelihood of arrhythmia.
How might exercise affect my ICD?
Your ICD detects abnormal heart rhythms in a number of ways, one of which relates to the speed of the heart during the arrhythmia. Most arrhythmias treated with ICDs will be significantly faster than your normal heart rate would reach, even with strenuous exercise. Occasionally, however, the ICD needs to be programmed to recognise abnormal heart rates that are close to those that can be achieved with exercise. For this reason, it is worthwhile to check how your ICD is programmed before undertaking anything other than recreational exercise or exercise to lose weight; your cardiologist, arrhythmia nurse or cardiac physiologists can advise you about how high you can safely raise your heart rate. If you are concerned about your safe exercise level, you should ask your cardiologist, arrhythmia/ICD nurse or cardiac physiologists whether an exercise test would be a helpful way to gain reassurance. If you are concerned you may also be referred to an exercise specialist within the cardiac rehabilitation team.
In order for you, and others around you, to feel safe about exercise the following information is useful: (1) the ICD detection threshold setting in beats per minute; (2) whether the device is set for ventricular tachycardia (VT) or ventricular fibrillation (VF); (3) rapid onset setting (how quickly the heart rate is allowed to increase before therapy is delivered); (4) sustained ventricular tachycardia settings (how long each episode should last before therapy is delivered); (5) ICD mode of therapy e.g. anti tachycardia pacing (ATP) or shocks; (6) are you taking beta blockers? Knowledge of these factors can reduce the anxiety in setting physical activity and exercise targets for you and people involved with exercise e.g. gym instructors. For example, a patient who is taking beta blockade, has a VF setting of 180bpm with a rapid onset setting of 30 beats and set for shock therapy (defibrillation) is very unlikely to experience arrhythmia or shock therapy with moderate intensity exercise.
Is there any exercise I definitely can’t do?
As a general rule, you should ask yourself “what would happen if my ICD goes off?” before undertaking any exercise. For most forms of recreational exercise, this probably means that someone who knows that you have an ICD should accompany you - often just to prevent well-meaning bystanders over-reacting! You should also ensure that you have your ICD card with you AT ALL TIMES, in case you need to be taken to hospital for any reason.
You should not undertake any contact sports. Although the ICD itself is very tough, bruising or breaking the skin over the site where the device is implanted may lead to infection, which can then become very troublesome to treat and resolve. You should also recognise that you are unlikely to be able to obtain insurance for winter sports such as skiing or, indeed any other ”extreme” sports where the effects of a shock may put you or others at risk.
Swimming can be undertaken once your implant wound has healed fully (although you should be accompanied at all times by someone able to get you out of the water should your ICD go off or in case you lose consciousness or feel unwell). Some ICDs are implanted for arrhythmias, which may be triggered specifically by swimming (some Long QT Syndromes - check with your cardiologist) but snorkelling is not recommended and SCUBA diving should not be undertaken. Water sports generally need to be undertaken only if you are accompanied at all times by at least one other person who is able to get you out of the water in case your ICD goes off.
You will not be able to take part in any form of competitive motor sports, as you will not be eligible for an appropriate licence. Regular driving should be discussed with your cardiologist. Latest regulations for ICD patients can be found on the DVLA website:
http:/www.direct.gov.uk/en/motoring/driverlicencing/medicalrulesfordrivers
You should also avoid any sport (or indeed any situation) where you might be exposed to strong magnetic or electrical fields or a powerful radio source (radio-controlled planes, cars, boats etc may be a problem - please check with your local implant centre).
So what can I do?
As discussed above, it is likely that your underlying heart condition (i.e. the cause of your arrhythmia and therefore the reason you had the ICD implanted) will have more influence on your ability to exercise than the presence of your ICD. Your underlying heart condition may limit your exercise capacity due to
hotness of breath, fatigue or chest pain - these should not be ignored.
Research has shown that physical activity and exercise are beneficial for people fitted with an ICD. Aerobic and skilled flowing movement, muscular endurance and flexibility should dominate the exercise and physical activity sessions. Such activities are very well tolerated, effective and lead to optimal carry-over into your daily life. There is a dose response relationship between the frequency and intensity of exercise prescription whereby the most favourable fitness improvements occur with a moderate intensity performed frequently.
Physical activity and exercise should be progressed slowly and should use one of the standard approaches of monitoring e.g. heart rate or perceived effort. An exercise intensity of between 60 to 75% target heart rate (220 minus age) is sufficient to bring about significant health benefits and improve fitness and endurance. If you are taking beta-blocker medication you may not be able to reach these heart rate levels. Instead you should look to increase your exercise heart rate by 30 to 40 beats above your resting heart rate.
Alternatively you can use the body’s built in monitor, which is your ability to rate your own effort or exertion. Imagine that sitting down equals ”zero” effort and a score of ten equals the ”most extreme” effort you could perform if pushed to do so. Now in your own mind split the distance between 0 and 10 by half and try to keep your effort or exertion below a score of five. The key is too avoid becoming too breathless during exercise, as this will sap your strength and over load your cardiovascular system.
In general, most exercises should be performed standing, with horizontal (lying down) and seated arm exercises kept to a minimum. Seated arm exercise with weights leads to excessive cardiac demand and an increased likelihood of arrhythmia. If seated exercise is to be performed then the intensity of exercise should be low and the emphasis placed on muscular endurance (lots of repetitions without feeling unduly fatigued). Slight leg exercise, for example alternate heel raises, when combined with arm exercise, reduces the load on the heart during seated arm work.
A note of caution is required for those few patients who are at risk of ICD lead problems. This situation is often known immediately post operatively and your ICD implant team will have informed you about it. In these circumstances it is important to avoid excessive shoulder range of movement and or highly repetitive vigorous shoulder movements. Light to moderate strength activities performed within a normal range of movement, that closely match functional daily activities have been used successfully in patients with an ICD.
Physical Fitness is soon lost if training is not continued at a level sufficient to maintain the effect. Moderate physical activity as well as leisure and sport are known to benefit health and where possible, these should be pursued most days of the week. Continuous physical activity of 30 minutes or more is considered most effective, although multiple activity sessions of 10 to 15 minutes duration, on the same day, have also demonstrated significant health improvement.
Summary
Physical activity and exercise has a substantial role in enabling patients with an ICD to take control of their condition. Exercise can be performed safely without increasing the risk of complications so long as the exercise is performed at the appropriate intensity and the exercise session incorporates a warm up and cool down period. The mode of exercise needs to be similar to daily activity, e.g. walking, in order to gain the most from exercise sessions and maintain the effect over years.
A long term, preferably lifestyle, approach to physical activity and exercise is essential if patients are to achieve the greatest benefits. If you have any remaining questions or need to clarify how any of the information in this leaflet relates specifically to you, please contact your local ICD implant centre, cardiologist, cardiac physiologists or arrhythmia/ICD nurse.
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