Pacing instruments can be used to treat patients suffering from various heart conditions that may result in a reduced ability of the heart to deliver sufficient amounts of blood to a patient's body.  These heart conditions may lead to rapid, irregular, and/or inefficient heart contractions.  To help alleviate some of these conditions, various devices (e.g., pacemakers, defibrillators, etc.)  can be implanted in a patient's body.  Such devices may monitor and provide electrical stimulation to the heart to help the heart operate in a more normal, efficient and/or safe manner.  In some cases, a patient may have multiple implanted devices that are configured to communicate information between the devices.