In the UK, holding an ICD will prevent you from holding a Group 2 licence, which covers lorries (LGV/HGV) and buses (PCV). If you currently hold a Group 2 licence, having an ICD implanted will typically result in its revocation by the DVLA.
This can be a significant and distressing consequence for professional drivers, and it is worth discussing the implications with your cardiologist before implantation where possible. In some circumstances, alternatives to ICD therapy may be considered, though this is always weighed carefully against the risk of sudden cardiac arrest.
If you drive professionally and have been told you need an ICD, speak to your cardiologist and contact the DVLA for specific guidance on your situation. Occupational health support from your employer may also be available.