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.
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:
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.
PAC can produce a fluttering, racing, or forceful heartbeat. The palpitations are usually transient and only last one or two beats.
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.
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.
Some of the known PAC causes and triggers include:
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)
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.
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).
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).
While premature atrial contraction (PAC) symptoms can occur at any age, certain factors make them more likely or frequent. They include the following:
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)
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.
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.
Premature atrial contraction symptoms are usually diagnosed by recording the heart’s electrical activity. Key diagnostic methods include:
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.
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.
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.
Electrolyte blood tests (potassium, magnesium, calcium) and thyroid blood tests are useful. Detection of an electrolyte imbalance or hyperthyroidism can correct a PAC trigger.
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:
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.
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.
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:
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.
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What is the PAC full form in medical science?
<p>The full form of PAC is premature atrial contraction.</p>
Are premature atrial contractions symptoms a sign of cardiovascular disease?
<p>Most premature atrial contraction (PAC) symptoms are natural and do not indicate cardiovascular disease. Frequent PACs are known to be present in cardiac diseases like coronary artery disease, cardiomyopathy, or high blood pressure. PACs can also be triggered by factors other than stress, such as caffeine, alcohol, and electrolyte imbalances.</p>
What does a premature atrial contraction symptom feel like?
<p>A premature atrial contraction (PAC) symptom can be experienced as a skipped or fluttering heartbeat for a quick moment. Some people describe it as:</p><p> </p><ul><li>Sudden thump or an extra beat in the chest</li><li>A slight pause and a stronger beat</li><li>A fluttering or pounding sensation</li><li>A rushing sensation of the heart</li></ul>
What does a premature atrial contraction symptom tell about blood pressure?
<p>Premature atrial contraction (PAC) symptoms may sometimes be associated with heart conditions, but it does not mean high or low blood pressure. Though frequent PACs may be more common in individuals with high blood pressure, the PACs themselves are not a direct cause or marker for hypertension.</p>
How to initiate a PSVT treatment?
<p>Treatment for PSVT includes vagal manoeuvres, such as deep breathing or bearing down, to slow the heart; medications such as adenosine or beta blockers to slow the rhythm; electrical cardioversion to reset the heart rate on an emergency basis; or catheter ablation in people who have severe recurring episodes or have problems with the electrical pathways in the heart.</p>
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