This depends on your specific situation and DVLA regulations, and you must not assume it is automatically permitted. After a cardiac arrest or ICD implant, there is typically a mandatory period during which you are not allowed to drive any motor vehicle, including a motorcycle. For motorcycles specifically, the risk is heightened because an ICD shock or loss of consciousness while riding could cause a serious accident.
DVLA rules on riding after an ICD implant or cardiac arrest are complex and depend on the type of arrest, the rhythm involved, your licence group, and whether your ICD was fitted prophylactically or following an event. You must notify the DVLA of your ICD and wait for confirmation before riding again. Do not ride until your cardiologist and the DVLA have both confirmed it is safe to do so.
Our page on driving and the DVLA after cardiac arrest covers the regulations in more detail. If your situation is not clear after reading this, raise it directly with your cardiologist or device nurse.