As is so common, this story unfolds late on a Friday afternoon—the worst time to have a medical problem. The cardiology fellow on call reassured me that my father’s pacemaker was not prolonging his life and that it wasn’t necessary to turn it off. He explained that the acidosis that occurs will make the myocardium nonresponsive to the signals from the pacemaker. This was an explanation that we would hear many times from many people. To me, a gynecologist with a medical school knowledge of cardiac electrophysiology, this explanation certainly made sense. But the fellow still gave me a phone number for the pacemaker company, and I called.