How does the ICD work?

The ICD continually monitors your heart rate. If it detects a fast heart rhythm it will respond in one or two ways. The ICD will be set up to respond to your individual heart rhythm, based on information about what has happened to you in the past or from the investigations that you have had.

The ICD may be set to ‘anti-tachycardia pace’ to try to override ventricular tachycardia and restore a normal rhythm without a shock being delivered to the heart. You may not be aware of this happening unless you feel unwell when you have your fast heart rhythm.

The ICD is also set to deliver a shock, through the wire inside the heart, to restore the normal rhythm. You may feel this like a big thump in your chest, but this feeling will pass very quickly. However, if you are walking it may make you stumble. If you feel unwell or sense that your heart is going too fast, stop and rest from what you are doing and get yourself in a comfortable position, ideally in a chair.

If anyone is touching you when the device gives you a shock they will not be harmed, but may experience a tingling sensation.