Atrial Premature Beats

(Atrial Ectopic Beats; Premature Atrial Contractions)

ByL. Brent Mitchell, MD, Libin Cardiovascular Institute of Alberta, University of Calgary
Reviewed/Revised Jan 2023

An atrial premature beat is an extra heartbeat caused by electrical activation of the atria (upper chambers of the heart) from an abnormal site before a normal heartbeat would occur.

(See also Overview of Abnormal Heart Rhythms.)

Atrial premature beats occur in many healthy people and rarely cause symptoms. Atrial premature beats are common among people who have lung disorders (such as chronic obstructive pulmonary disease) and are more common among older people than among younger people. These beats may be caused or worsened by consuming coffee, tea, or alcohol and by using some cold, hay fever, and asthma remedies.

Atrial premature beats only rarely cause symptoms. Sometimes the person is aware of the heat beat (palpitations).

ECG: Reading the Waves

An electrocardiogram (ECG) represents the electrical current moving through the heart during a heartbeat. The current's movement is divided into parts, and each part is given an alphabetic designation in the ECG.

Each heartbeat begins with an impulse from the heart's pacemaker (sinus or sinoatrial node). This impulse activates the upper chambers of the heart (atria). The P wave represents activation of the atria.

Next, the electrical current flows down to the lower chambers of the heart (ventricles). The QRS complex represents activation of the ventricles.

The ventricles must undergo an electrical change to get ready for the next heart beat. This electrical activity is called the recovery wave, which is represented by the T wave.

Many kinds of abnormalities can often be seen on an ECG. They include a previous heart attack (myocardial infarction), an abnormal heart rhythm (arrhythmia), an inadequate supply of blood and oxygen to the heart (ischemia), and excessive thickening (hypertrophy) of the heart's muscular walls.

Certain abnormalities seen on an ECG can also suggest bulges (aneurysms) that develop in weaker areas of the heart's walls. Aneurysms may result from a heart attack. If the rhythm is abnormal (too fast, too slow, or irregular), the ECG may also indicate where in the heart the abnormal rhythm starts. Such information helps doctors begin to determine the cause.

Atrial premature beats may be suspected during a physical examination showing an irregular pulse and are confirmed by electrocardiography (ECG).

Treatment of Atrial Premature Beats

  • Sometimes, antiarrhythmic drugs

Rarely, when these beats occur frequently and cause intolerable palpitations, treatment is necessary. Antiarrhythmic drugs are usually effective (see table Some Drugs Used to Treat Arrhythmias). If the cause is identified, it is treated.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. American Heart Association: Arrhythmia: Information to help people understand their risks of arrhythmias as well as information on diagnosis and treatment

Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID