What Is a Wandering Atrial Pacemaker?
A wandering atrial pacemaker is a type of heart arrhythmia. An arrhythmia is a problem with the rhythm or rate of your heartbeat. Types of arrhythmias include having extra beats, a fast or slow rate, or an irregularity that occurs in the lower chambers of the heart.
Some arrhythmias are serious medical conditions, while others, like having extra beats, are common and nothing to be worried about. To be safe, you should see your doctor if you experience any inexplicable and unusual heartbeat.
How Blood Moves Through the Heart
The rhythm and rate of your heartbeat are related to how blood moves through your heart. The heart has two upper chambers, the atria, and two lower, the ventricles. Blood from your body comes into the right atrium, then into the right ventricle, where it flows out to the lungs.
On the left side, blood comes into your left atrium after picking up oxygen in your lungs. It then goes into the left ventricle and is pumped out to the rest of your body, carrying oxygen.
Electrical Impulses Control Contractions
To move blood between the chambers of your heart, your heart muscle needs to contract. In other words, the atria and ventricles squeeze to move blood into the next chamber or blood vessel.
These contractions are controlled by electrical impulses that come from specialized cells. These cells are able to conduct electricity and transmit impulses along to more cells. As a result, your heart chambers contract with a certain rate and rhythm that keeps blood moving.
Your Natural Pacemaker
A set of cells on the top of the right atrium of your heart, called the sinoatrial (SA) node, begins and controls the rate and rhythm of electrical impulses. For this reason, the SA node is often called the natural pacemaker. This node is responsible for keeping your heart contracting—and, therefore, beating—at the appropriate rate and with a regular rhythm.
The AV Node
Your SA node, or natural pacemaker, is responsible for conducting the impulses that control your heartbeat, but it has partners as well. From the SA node, electrical impulses move to the atrioventricular (AV) node, a little further down in the heart. From here, the impulse continues on to fibers that carry the signal through the heart and maintain the rest of the heart’s synchronized contractions.
The Wandering Pacemaker
A wandering atrial pacemaker is an arrhythmia that occurs when the control of your heart’s electrical impulses wanders from the SA node to the AV node. This shift can cause an irregularity in your heartbeat, but it may not. You may not ever notice when you have a wandering pacemaker.
The wandering can occur in different situations, such as when you are working out or sleeping. It is almost never a cause for concern.
An electrocardiogram, or ECG, is a diagnostic tool that is used to measure the electrical activity in your heart. On an ECG reading, which looks like a series of waves, there is a peak that represents the contraction of your right atrium caused by the SA node, the P wave.
Your doctor can tell that you have a wandering atrial pacemaker if you have an irregularity in the P wave on your ECG. The shape, size, and position of your P wave may look different.
Who Gets a Wandering Atrial Pacemaker?
Anyone can get a wandering atrial pacemaker, but it is more common in older adults and young children. It is also common in athletes and other people who are in excellent physical condition. Why this is the case is unknown. In rare cases, a wandering pacemaker can be caused by digoxin toxicity, a complication of digitalis therapy for heart conditions.
Multifocal Atrial Tachycardia
There is another type of arrhythmia that is similar to a wandering pacemaker but is more serious. It is called multifocal atrial tachycardia. In this condition, rather than wandering, the different nodes in the heart fire off electrical impulses at the same time. This often causes a rapid heart rate, which distinguishes it from a wandering pacemaker. This type of arrhythmia can cause serious problems and needs treatment.
Causes and Treatment
It is not understood what causes a wandering atrial pacemaker in most cases. The good news is that it is a condition that does not require treatment. The exception is when it is caused by digoxin toxicity. Digitalis is a heart medicine, and if it is the cause of wandering atrial pacemaker, its use may need to be halted or reduced.
- Booth, K.A. et al. (2008). ECG Interpretation and Clinical Significance. In Electrocardiography for Health Care Personnel (2nd ed., Chapter 5). Retrieved July 9, 2013, from http://highered.mcgraw-hill.com/sites/dl/free/007351098x/451682/sample_ch05.pdf
- Hebar, A. K. & Hueston, W.J. (2002, June 15). Management of Common Arrhythmias: Part I. Supraventricular Arrhythmias. American Family Physician, 65(12), 2479-2487. Retrieved July 3, 2013, from http://www.aafp.org/afp/2002/0615/p2479.html
- Multifocal Atrial Tachycardia. (2012, June 18). National Institutes of Health. Retrieved July 3, 2013, from http://www.nlm.nih.gov/medlineplus/ency/article/000186.htm
- Your Heart’s Electrical System. (2011, November 17). National Heart, Lung, and Blood Institute. Retrieved July 3, 2013, from http://www.nhlbi.nih.gov/health/health-topics/topics/hhw/electrical.html