Atrial premature complexes (APCs) are a type of irregular heartbeat that originates in the atria. APCs cause premature heartbeats to occur. Depending on the cause, people may not require treatment.

APCs are a type of arrhythmia. This is the term for an irregular heartbeat. If a person has arrhythmia, they may have a heartbeat that:

  • is too fast
  • is too slow
  • has an irregular rhythm

APCs are a type of arrhythmia that causes a person to develop an irregular rhythm due to premature heartbeats originating in the atria. Medical professionals also refer to APCs as premature atrial contractions.

In this article we explain what APCs are and outline their causes. We also discuss diagnosis and treatment of APCs and how to prevent arrhythmias.

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The heart has four chambers. The two upper chambers are the atria, and the two lower chambers are the ventricles.

When the heart beats, it pumps blood through the chambers through valves, which open and close to let blood flow in the correct direction.

A premature complex causes an extra heartbeat to occur that happens prematurely. A person has APCs when this premature heartbeat originates in their atria.

If a person has a premature heartbeat that originates in their ventricles, they have premature ventricular complexes.

When a person has APCs, the extra heartbeat can cause the person’s next normal heartbeat to be more forceful.

APCs are often benign and nonthreatening in isolation. However, if a person has APCs alongside an underlying medical condition, this may foreshadow early mortality.

Certain diseases and health conditions can cause a person to develop APCs. Medical professionals refer to these as structural causes of APCs.

Structural causes of APCs typically include:

Chemicals in certain medications can also cause a person to develop APCs. Medical professionals refer to these as chemical-based causes of APCs.

Chemical-based causes of APCs include:

APCs may also occur as an after-effect of another condition. Other conditions that may cause a person to develop APCs include:

Medical professionals also believe that the following may contribute to APCs:

People with APCs often display no symptoms.

The most common symptoms that have an association with APCs are the sensation that the heart has skipped a beat and heart palpitations. Other symptoms of APCs include shortness of breath and anxiety.

If a person has APCs that are consistent and do not go away, they may experience signs and symptoms of heart failure.

In a lot of cases, a person with APCs will experience no symptoms. If this is the case, a doctor may discover they have APCs as part of a routine checkup or when examining a person for an unrelated condition.

If a doctor suspects a person has APCs, they may use an electrocardiogram (ECG) to confirm their diagnosis.

An ECG allows a medical professional to record the heart’s electrical activity. By analyzing the heart’s electrical activity, a medical professional may be able to determine where the irregular heartbeat is originating from and confirm a diagnosis of APCs.

Once a doctor has confirmed their APCs diagnosis, they may use an echocardiogram to determine the functional status of the heart and identify possible underlying structural causes of the APCs. An echocardiogram is a type of ultrasound scan that looks at the heart’s structure and the nearby blood vessels.

If a person has frequent APCs, they should receive an evaluation for structural heart disease.

Treatment for APCs can depend on the following factors:

  • symptoms
  • triggers
  • structural causes

Typically, people with no symptoms do not require treatment.

If a person has APCs that occur due to chemical triggers, their treatment may include avoiding these triggers. This can mean avoiding certain medications.

If a person has an underlying condition that is causing their APCs, they may require treatment for that condition.

In some cases, a person may take certain medications to help treat their APCs symptoms. These can include beta-blockers, which are medications that lower stress on the heart by blocking the action of adrenaline. Low doses of beta-blockers are relatively safe and often make up the first-line treatment for symptomatic APCs.

Other medications can include antiarrhythmic agents. These medications can suppress the APCs’ origin to help reduce symptoms. Doctors will often only use these medications after careful consideration due to the fact that they can cause a person to develop new arrhythmias. Doctors may prescribe:

  • type IA antiarrhythmic agents
  • type IC antiarrhythmic agents
  • type III antiarrhythmic agents

If a person has APCs related to heart disease and heart failure, they may require treatment. Treatment can include catheter ablation of the origin of the APCs.

Catheter ablation is a procedure that uses radiofrequency energy to destroy a small area of the heart tissue. The procedure aims to destroy the tissue that causes the irregular heartbeat, which can restore the heart’s regular rhythm.

During the procedure, a doctor inserts thin tubes — catheters — through the blood vessels to the heart. These catheters can record the heart’s electrical activity to locate the abnormal heart tissue that is causing the arrhythmia.

The doctor then places the catheter at the exact site where these abnormal cells are. The catheter emits a mild radiofrequency energy, which destroys the heart muscle cells in a very small area.

In order to prevent arrhythmia, a person may wish to follow some of these steps:

  • avoid triggers for arrhythmias
  • treat any conditions that may cause arrhythmias
  • make heart-healthy lifestyle choices, such as:
    • eating heart-healthy foods
    • being physically active
    • maintaining a healthful weight
    • avoiding smoking tobacco
    • managing stress

If a person has a premature complex, it causes an extra heartbeat to occur. This heartbeat happens prematurely. If this extra heartbeat originates in the atria, a person has atrial premature complexes (APCs).

Structural causes of APCs include coronary artery disease, hypertrophic cardiomyopathy, and valvular heart disease. Certain chemicals and medications can also cause a person to develop APCs. These include beta-agonists, digoxin, and chemotherapeutic agents.

Isolated APCs are often benign and nonthreatening. If a person has APCs alongside an underlying medical condition, this may foreshadow early mortality. Treatment for APCs can include medications and catheter ablation.