I ve never heard of this being done by appointment, but in cases where there is ventricular tachycardia or an arrythmia, it is accepted practice to calm or stop the heart temporarily and then restart it again with electrical shocks administered with a cardiac defibrillator. They don t kill the heart, they momentarily stop it from beating. It can also be that they intend to place pacemaker to regulate the heartbeat. In that particular procedure, a internal cardiac defibrillator is placed into the heart under a local anesthetic. It can be intended to be placed permanently or temporarily, which ever is most appropriate. In this case, the pacemaker monitors the activity of the heart and delivers a shock as needed to reset the correct rhythm back again. Lots of people have pacemakers, and it s not the same as it used to be years ago when it was a major operation with lots of complications. Regardless of which is used, they will not be killing your grandfather s heart, and he will be in very little danger actually. While they do the procedure they will have everything nearby in case there is a problem, and he will be in a hospital. If you are going to have a heart problem, having one in the hospital with the cardiologist right there is probably the best scenario of all. Your grandfather will most likely do just fine, and will feel much better once it s done. In the meantime, you can do a web search on pacemakers and find out lots of information for yourself so you will understand this all better and can feel calmer. Good luck to both of you. It s natural to be a bit scared, but nothing worth a panic.