Yes. If you enter a hospice or reach the end of life, the shock therapy delivered by your ICD can be deactivated. This is a legal, ethical, and clinically supported option in the UK, and one that your clinical team should raise proactively as part of end-of-life planning rather than leaving it to you to ask.
The reason deactivation is worth considering is that an ICD will continue to deliver shocks in response to dangerous arrhythmias even in the final stages of life, when those shocks will not change the outcome and may cause distress. Deactivating the shock therapy means the device stops delivering those interventions, while pacing functions, if present, can usually remain active if they are providing comfort.
Deactivation is not the same as switching off the heart. It simply removes one layer of treatment that is no longer appropriate. It can be reversed at any point if your wishes change.
The decision is made jointly between you, your family if you wish, and your clinical team. An advance decision to refuse treatment (ADRT) can also be used to document your wishes in advance, including your preferences about ICD shock therapy at end of life. The British Heart Foundation and the Resuscitation Council UK both provide guidance on this.
If you are in this situation and your clinical team has not raised the subject, it is entirely appropriate to bring it up yourself or to ask a hospice nurse to help facilitate the conversation.