A wandering pacemaker is a type of arrhythmia characterized by a shifting in the location of the heart's natural pacemaker. The result is an irregular heartbeat, with a P wave — the wave which indicates a shift of electrical activity from the right atrium to the left atrium — that moves around when the heartbeat is viewed on an electrocardiograph (ECG). This arrhythmia is usually not a cause for concern and it does not require further treatment. However, there may be cases in which it is associated with another health problem which does require attention.
The heart's natural pacemaker is located in the sinoatrial (SA) node, an area in the upper portion of the right atrium. This area includes a cluster of pacemaking cells which determine the heart's rhythm. In someone with a wandering pacemaker, sometimes cells in the atrioventricular (AV) node, in the lower area of the right atrium, take over pacemaking duties temporarily. This results in irregularities in the heartbeat that the patient can usually feel, and which will also show up as irregularities on an ECG.
The vagus nerve is a nerve which regulates the heartbeat; it's "tone" is the level of activity or impulses sent by the nerve. A decrease in vagal tone can cause the AV node to start regulating the heartbeat. When the tone increases, the SA node will resume its proper role. This type of malfunction can occur in response to stress and other pressures and may occur independently or in connection with certain medications or conditions.
A doctor can diagnose a wandering pacemaker with the assistance of an ECG to visualize the heartbeat. By examining the patterns on the ECG, the doctor can determine not only that the patient has an arrhythmia, but what kind of arrhythmia the patient has, and what may be causing it. Wandering pacemakers are a form of atrial arrhythmia, because they originate in the right atrium of the heart.
Patients who have a wandering pacemaker may want to make sure that it is noted on their charts so that when they interact with new care providers, their care providers will not be concerned or startled by the arrhythmia. It may also be necessary for some patients to attend cardiology appointments for the purpose of monitoring heart function to confirm that the heart is still healthy and to determine whether or not more aggressive treatment options should be pursued.