Premature Atrial Contractions (PACs)
Common, usually harmless extra heartbeats
Quick Facts
- Type: Heart rhythm variation
- Origin: Upper heart chambers (atria)
- Common triggers: Caffeine, stress, alcohol, fatigue
- Usual outlook: Benign in healthy hearts
Overview
Premature atrial contractions (PACs) are early, extra heartbeats that begin in the upper chambers of the heart, called the atria, instead of the heart's normal pacemaker. They interrupt the regular rhythm and are often felt as a "skipped" beat, a flutter, or a thump in the chest, frequently followed by a brief pause.
PACs are very common and occur in many healthy people, often without any underlying heart problem. Most of the time they are harmless and do not require treatment. Occasionally, frequent PACs can be a sign of, or a trigger for, other rhythm disturbances such as atrial fibrillation, which is why persistent or troublesome symptoms are worth evaluating.
Symptoms
Many people with PACs have no symptoms and are unaware of them. When symptoms occur, they may include:
- A sensation of a skipped or extra heartbeat
- A fluttering or flip-flop feeling in the chest
- A brief pause followed by a stronger beat
- Awareness of the heartbeat (palpitations)
- Occasionally a fleeting sense of lightheadedness
Symptoms are often more noticeable when resting, lying down, or after caffeine, alcohol, or stress. PACs themselves rarely cause serious symptoms. Fainting, severe chest pain, or sustained rapid heartbeats with shortness of breath are not typical of simple PACs and should be evaluated promptly.
Causes
PACs occur when a small area in the atria fires an electrical signal earlier than the heart's normal pacemaker. Common triggers and contributing factors include:
- Caffeine, alcohol, and tobacco
- Stress, anxiety, and lack of sleep
- Fatigue or strenuous exercise
- Certain medications and stimulants, including some cold and asthma remedies
- Dehydration or electrolyte imbalances
- Thyroid problems, particularly an overactive thyroid
- Underlying heart or lung conditions in some people
In many healthy individuals, no specific cause is found, and PACs simply reflect normal variation in the heart's electrical activity.
Risk Factors
Factors that make PACs more likely or more frequent include:
- Older age
- High caffeine, alcohol, or tobacco use
- Stress and poor sleep
- High blood pressure or existing heart disease
- Lung disease
- Thyroid disorders
- Electrolyte imbalances
PACs become more common with age and may increase during illness, stimulant use, or periods of stress, even in people with otherwise healthy hearts.
Diagnosis
PACs are diagnosed by recording the heart's electrical activity. Tests may include:
- Electrocardiogram (ECG): Captures PACs if they occur during the brief recording.
- Holter or event monitor: A portable device worn for 24 hours to several weeks to record the heart rhythm during daily life and count how often PACs occur.
- Blood tests: To check for thyroid problems or electrolyte imbalances.
- Echocardiogram: An ultrasound of the heart to look for underlying structural heart conditions when indicated.
These tests confirm that the extra beats are PACs, estimate how frequent they are, and help determine whether an underlying condition is present.
Treatment
Most PACs need no specific treatment, especially when they are infrequent and the heart is otherwise healthy. Management focuses on reassurance and reducing triggers:
- Lifestyle changes: Cutting back on caffeine, alcohol, and tobacco; improving sleep; and managing stress.
- Correcting causes: Treating thyroid disorders, electrolyte imbalances, or other contributing conditions.
- Medications: For people with bothersome, frequent symptoms, medicines such as beta blockers can reduce the awareness and frequency of PACs.
- Treating underlying heart disease: When PACs are linked to another heart condition.
- Catheter ablation: Rarely considered for very frequent, symptomatic PACs that do not respond to other measures.
Because simple PACs are benign, treatment is usually aimed at comfort rather than eliminating every extra beat.
Prevention
You may reduce how often you notice PACs by:
- Limiting caffeine, alcohol, and tobacco
- Getting adequate, regular sleep
- Managing stress and anxiety
- Staying well hydrated
- Treating thyroid and other medical conditions as advised
- Reviewing stimulant-containing medicines or supplements with your provider
Identifying your personal triggers and avoiding them is often the most effective way to reduce symptomatic PACs.
When to See a Doctor
See a healthcare provider if you have frequent or bothersome palpitations, or if extra beats are new, increasing, or affecting your quality of life, so the rhythm can be checked. Tell your provider if you also have heart disease, high blood pressure, or thyroid problems.
Seek urgent or emergency care if palpitations are accompanied by chest pain, severe shortness of breath, fainting or near-fainting, or a sustained, very fast heartbeat. These symptoms are not typical of simple PACs and may indicate a more serious rhythm or heart problem that needs immediate attention.
Frequently Asked Questions
Are premature atrial contractions dangerous?
In people with otherwise healthy hearts, PACs are usually harmless and need no treatment. Frequent PACs can occasionally be linked to other rhythm problems like atrial fibrillation, so persistent symptoms are worth checking.
What do PACs feel like?
They are often felt as a skipped or extra beat, a flutter, or a thump in the chest, sometimes followed by a brief pause. Many people have no symptoms at all and never notice them.
What triggers PACs?
Common triggers include caffeine, alcohol, tobacco, stress, poor sleep, dehydration, and certain medications. Thyroid problems and electrolyte imbalances can also increase them.
How are PACs treated?
Most need no treatment beyond reducing triggers like caffeine and stress. For bothersome symptoms, medicines such as beta blockers may help, and any underlying condition is treated. Procedures are rarely needed.
When should I see a doctor about extra heartbeats?
See a doctor if palpitations are frequent, new, or affecting your life, especially with heart disease or thyroid problems. Seek emergency care if you also have chest pain, severe breathlessness, fainting, or a sustained fast heartbeat.
References
- Mayo Clinic. Premature atrial contractions.
- American Heart Association.
- MedlinePlus, U.S. National Library of Medicine.