What Are Premature Atrial Complexes?

What Are Premature Atrial Complexes?
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Understanding Early Atrial Complexes

The sinus node is a small structure that is located near the top of the right atrium of the heart. This node plays an important role in controlling normal heart rhythm by discharging electrical signals. Premature electrical signals can produce premature atrial complexes at different locations in the atria. Such premature complexes are nothing more than premature or early heart beats.

A premature atrial beat is followed by a pause. The subsequent heart beat is longer and stronger than normal as it needs to pump the accumulated blood out of the heart chamber. The incidence of premature atrial beats increases at slower basic sinus bradycardia rates. Premature complexes can occur occasionally, in a regular pattern or several may occur at one time. Most people have such premature beats at some time or the other in their lives.


Age and the ingestion of stimulants such as alcohol, tobacco or drugs can trigger premature heart beats. Stress and medications prescribed for common colds can also act as a trigger. Besides this, medical conditions such as lung disease, enlarged atria or circulatory problems can all cause premature atrial beats.


Generally, such premature heart beats go unnoticed as they are symptomless. Sometimes, the affected person experiences mild palpitations. Others feel as though their heart has skipped a beat and this feeling is followed by a thumping in the chest that’s caused by the subsequent stronger heart beat.

Diagnosis and Treatment

A thorough physical exam and an evaluation of the patient’s medical history will enable the doctor to confirm the diagnosis. Diagnostic tests such as an ECG, or electrocardiogram, can help the medical practitioner determine whether or not the patient is suffering from premature atrial beats. An ECG shows a heart beat in a 3 wave form. The first wave is known as P, the second as QRS and the third as T. When a premature atrial complex or premature heartbeat occurs, the P wave is observed to occur closer than expected to the preceding T wave on the ECG. Treatment is only prescribed if the patient complains of discomfort caused by the frequent occurrence of such heartbeats. Medications such as beta-adrenergic antagonists or calcium channel antagonists are found to be effective.

Possible Complications

Although premature atrial complexes are harmless, they can lead to atrial tachycardia or episodes of very rapid and regular heartbeats. This is because they cause excitation of ventricles at the atrioventricular nodal system. They can also lead to a decrease in cardiac output or the amount of blood being pumped out by the heart in a specified amount of time.


Premature atrial complexes are common and benign and the prognosis for people who have such premature heartbeats is good. Avoid stimulants such as alcohol, tobacco and drugs. Try to lead a life that’s less stressful and make sure you get yourself treated if you’re suffering from any existing medical conditions such as lung disorders.


American Heart Association: Atrial Ectopic Activity Associated with Sinus Bradycardia

American Heart Association: The Role of Premature Beats in the Initiation and the Termination of Supraventricular Tachycardia in the Wolff-Parkinson-White Syndrome

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