I know of a guy who had a defective pacemaker.

While he was having a shower, he got shocked, he assumed it was electricity. After a few more shocks, he quickly realized that it's his pacemakers. He took a number of additional shocks before he was sedated in a hospital.

Now, he's still got the pacemaker inside, but it's off. It turns out that the company making the pacemakers knew that a small percentage were defective and that things like this could happen (unfortunately, I don't know what company that is).

He's lucky he's still alive. He said that he's never going to have another (active) pacemaker - he'd rather die than have to go through such painful experience again.