Premature Atrial Contraction (PAC)- Symptoms

Causes and Symptoms of Premature Atrial Contractions Explained

Premature atrial contractions (PACs) are extra heartbeats that begin in the atria, instead of the sinoatrial (SA) node. PACs are a form of supraventricular arrhythmia, whereas premature ventricular contractions (PVCs) arise in the ventricles. Then, the SA node resets its timing, and each PAC is followed by a compensatory pause.

In an extensive study, about 99% of adults had at least one PAC while being monitored on a 24-hour heart monitor, showing that occasional PACs are very common. This means that many PACs are transient and only occur long enough for a single short ECG to detect them, in only 0.5% of people.

Keep reading to learn more about the symptoms, causes, diagnosis and treatment of premature atrial contractions.

What are the Symptoms of Premature Atrial Contraction?

PAC full form in medical term, is premature atrial contractions. It often produces no symptoms and is discovered incidentally. When symptoms occur, they usually involve an abnormal sensation of the heartbeat. Some of the common symptoms include:

Skipped or Extra Heartbeats

A 'brief pause' or a firm 'thump' is felt when a PAC interrupts the normal rhythm. Each sensation is only a few fractions of a second before the heart returns to normal rhythm.

Palpitations or Pounding

PAC can produce a fluttering, racing, or forceful heartbeat. The palpitations are usually transient and only last one or two beats.

Shortness of Breath or Chest Pain

If PACs occur in clusters or are frequent, mild breathlessness or chest discomfort can be seen. One PAC leads to only a small, temporary drop in cardiac output, and these symptoms are generally mild.

Anxiety or Dizziness

When a PAC occurs, some people feel momentary anxiety, lightheadedness, or weakness. Typically related to the unexpected ‘skip’ feeling, which improves when the rhythm returns to normal.

What are the Causes of Premature Atrial Contraction Symptoms?

Some of the known PAC causes and triggers include:

Cardiac Factors

PAC can be provoked by anything that negatively affects blood flow and damages atrial tissue. Some examples are reduced blood supply (ischemia), atrial scarring from injury or surgery, inflammation, or structural heart disease (e.g. coronary artery disease or cardiomyopathy)

Electrolyte and Hormonal Imbalances

PAC can occur with abnormal blood levels of minerals (especially potassium or magnesium) or thyroid hormones. For instance, hyperthyroidism causes extra atrial beats, and so do low potassium and magnesium levels.

Stimulants

High intake of caffeine, alcohol or nicotine commonly precipitates PAC. Atrial ectopic beats can also be caused by recreational drugs (e.g. cocaine, amphetamines) and some medications (decongestants, asthma inhalers, some antidepressants).

Stress 

PAC can result from physical or emotional stress, sleep deprivation, dehydration, fever, or acute illness. It may be transient during severe illness (e.g., infection, surgery).

What are the Risk Factors of Premature Atrial Contraction?

While premature atrial contraction (PAC) symptoms can occur at any age, certain factors make them more likely or frequent. They include the following:

Existing Heart Disease

PACs have become more common among elderly people with known heart disease. However, the atrial tissue substrate can be changed by chronic conditions (e.g., prior heart attack, atrial cardiomyopathy)

Metabolic Conditions

PACs are more frequent in people with high blood pressure, diabetes and abnormal cholesterol (low HDL). These factors may lead to atrial strain and metabolic stress on the heart.

Lifestyle Factors

Smoking cigarettes, drinking excessive amounts of caffeine or alcohol, and using stimulant drugs all significantly increase your PAC risk. Triggers include chronic stress, anxiety or poor sleep hygiene.

How is Premature Atrial Contraction Diagnosed?

Premature atrial contraction symptoms are usually diagnosed by recording the heart’s electrical activity. Key diagnostic methods include:

Electrocardiogram (ECG)

PACs in medical labs are usually captured on a standard 12-lead ECG. A PAC will appear as a premature P wave and a compensatory pause on the ECG. The QRS complex is normal, as the ventricles still naturally depolarise. With this ECG pattern, the extra beat can be confidently shown to originate from the atria.

Ambulatory Monitoring

Doctors often use a Holter monitor (24 to 48 hours) or an event recorder (up to 1 to 2 weeks) to capture PAC because it can be intermittent. Modern wearable ECG devices can also monitor PAC during daily activities.

Echocardiogram

A heart ultrasound is often indicated to look for underlying problems. Atrial size or function, valve disease, or ventricular function that might explain PAC can be evaluated with echocardiography.

Laboratory Tests

Electrolyte blood tests (potassium, magnesium, calcium) and thyroid blood tests are useful. Detection of an electrolyte imbalance or hyperthyroidism can correct a PAC trigger.

How is Premature Atrial Contraction Treated?

Most isolated premature atrial contraction (PAC) symptoms require no active treatment. Management focuses on symptom relief and addressing any causes or risk factors. Key points include:

Medications

Initially, low-dose beta blockers (such as metoprolol) are used to suppress ectopic beats and relieve palpitations. In some cases, other antiarrhythmic drugs, such as flecainide or propafenone, are used under specialist guidance only.

Catheter Ablation

For PACs that are recurrent and refractory to medications, catheter ablation may be performed. In this procedure, an electrophysiologist identifies the same atrial site, firing and destroying the PAC.

It’s always wise to have health insurance to safeguard your health and finances. At Star Health, we offer coverage for PAC treatment under our Star Cardiac Care Insurance Policy. We also provide hassle-free claim settlements with reduced turnaround time across over 14,000 network hospitals in India.

How to Prevent Premature Atrial Contraction?

There is no guaranteed way to prevent premature atrial contraction symptoms, but general heart-healthy measures can reduce their occurrence. Some of these measures include:

• Adopt a Healthy Lifestyle:Regular physical activity, a balanced diet, staying healthy and lean, being well hydrated, and getting quality sleep all help support the overall health and function of the heart.
• Limit Stimulants:Avoid or minimize caffeine, alcohol or nicotine since these can trigger ectopic beats. Some cold and allergy medicines (with stimulants) should also be used with caution.
• Manage Stress:Practice relaxation techniques, including deep breathing, meditation, and exercise, that manage stress. Chronic stress and poor sleep are some known PAC triggers.

Most PACs are harmless and don’t cause heart trouble. However, high PAC counts may increase the chance of a stroke or atrial fibrillation. Though most people can lead everyday lives with precautions, regular follow-ups are advised for those with risk factors.