What should I expect after implantation of pacemaker or defibrillator?

Please see the details for the defibrillator or pacemaker implantation. However, unique to biventricular pacing, the left ventricular lead passes very close to a nerve that runs along the surface of the heart from the spine down to the diaphragm. This is called the phrenic nerve. If the left ventricular leave stimulates it, it can cause a twitch of the left side of the diaphragm with every heartbeat. This is not dangerous but can be quite aggravating. It can usually be corrected by reprogramming the pacemaker or defibrillator in the office. We frequently watch people overnight because of the potential for phrenic nerve stimulation.