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Topic Overview

Implantable cardioverter-defibrillators (ICDs) are designed to treat potentially life-threatening ventricular arrhythmias, which are often recorded as dangerously high heart rates (tachycardia). The ICD is programmed to discharge at a specific rate, reducing potentially dangerous arrhythmias.

People with ICDs who are eligible for exercise training should be knowledgeable and comfortable with the benefits and limitations of their devices and have no abnormal heart rhythms or rates. Ask your doctor before beginning a new exercise program.

Whenever possible, people with ICDs should be monitored by electrocardiography (ECG, EKG) telemetry during exercise. Also, it is important to know and understand that ICDs are set to discharge at a specific heart rate. Therefore, your target heart rate during exercise should be at least 10 to 15 beats below the ICD discharge heart rate.

When to call a doctor

Call your doctor right away if you have symptoms that could mean your device is not working properly, such as:

• Your heartbeat is very fast or slow, skipping, or fluttering.
• You feel dizzy, lightheaded, or faint.
• You have shortness of breath that is new or getting worse.

After an ICD shock

Be sure you have a plan for what to do if you get a shock. Talk to your doctor if you are not sure. In general, your plan depends on how you feel after you get a shock and how many times you get a shock.

After one shock:

• Call or other emergency services immediately if you feel bad or have symptoms like chest pain.
• Call your doctor soon if you feel fine right way. Your doctor may want to talk about the shock and schedule a follow-up visit.

After a second shock within 24 hours:

• Call your doctor immediately, even if you feel fine right away.

Using RPE as an alternative measure

Rating of perceived exertion (RPE) is a valuable and reliable indicator in monitoring your exercise tolerance. It is usually used as part of an organized cardiac rehab program and may be valuable for those who have trouble monitoring their heart rate. It is probably most useful to first learn about RPE with a health professional (such as an exercise physiologist or trainer), and then you may be able to use it when you exercise on your own. For more information, see Monitoring Your Rating of Perceived Exertion (RPE).