Should a patient continue to have the implantable defibrillator even after bypass surgery?

It depends: Usually yes but it depends on the original indication for the icd.

Depends: An implantable defibrillator is used to treat the onset of a sudden, unstable rhythm in the heart. If that potential problem is of high likelihood, than yes. If your doctor is suggesting it, ask him or her what the reason is. Typically, these are not inserted strictly for prophylactic reasons.