Question:
Answer:
If you are in the advanced stages of heart disease and the shocks of your defibrillator cause pain and anxiety, and there is the frightening prospect of your last moments being full of these shocks, it is permissible to disable it, even though you may die sooner. You will die more peacefully. Disabling the defibrillator is no different from not doing CPR on someone who is clearly about to die: it can be a humane and rational decision.
On the other hand, there does not appear to be a good reason to remove a pacemaker, since it does not cause any discomfort, and removing it, in the case of one who is dependent on it, means pretty much instant or very swift death. It would basically be turning off the switch on your heart. So, effectively, in most cases, this would be a kind of direct killing.
My considered answer is yes to disabling the defibrillator if it is becoming a source of great discomfort, but no to disabling the pacemaker, which involves no discomfort and the removal of which causes death quickly.
Of course, I do not have all the details of your situation, and I trust you are getting sound medical information about your case so as to decide tranquilly and rationally what you want to do. I will certainly pray for you at my Holy Mass here at Catholic Answers.