Premature atrial contractions (PACs) are extra heartbeats that occur in the atria of the heart. (The atria are the two chambers in the heart that receive blood from the veins.)
PAC is the most common type of heart Arrhythmia , where the heart beats too slowly or too fast. In fact, an estimated 50 percent of people with or without heart disease have heart disease. While PACs themselves are generally benign (harmless), some studies suggest they may be associated with increased cardiovascular risk.
This article will explain the symptoms and causes of PAC and how to treat it.
normal heart rhythm
The heart’s rhythm is controlled by tiny structures called the sinoatrial node, which are located near the top of the heart’s right atrium. The sinoatrial node produces electrical signals that initiate and control the heartbeat.
Typically, the sinus node releases 50 to 90 of these electrical pulses per minute at rest. When a person’s heart rhythm is controlled by the sinus node in this normal way, healthcare providers often refer to it as normal sinus rhythm.
chambers and valves of the heart
In the vast majority of people, PACs cause no symptoms at all. However, some people experience heart palpitations that they usually describe as:
- A “jumping” feeling
- unusually strong heartbeat
PACs are early (i.e. premature) electrical impulses generated in the atria, but not from the sinoatrial node. PACs temporarily interrupt normal sinus rhythm by inserting an extra heartbeat.
Because the PAC resets the sinoatrial node, there is usually a brief pause before the next normal heartbeat occurs. That’s why PAC is often thought of as a jump in the heartbeat.
In a study of more than 1,700 healthy adults, 99 percent had at least one PAC during 24-hour cardiac monitoring.
PAC palpitations are more likely after taking alcohol, nicotine, or drugs containing stimulants.
Many experts believe that caffeine may cause PAC, but studies have yet to confirm this relationship in the general population.
How important are PACs?
Most healthcare providers generally consider PAC to be a normal change.
That said, PACs may be at risk for people with atrial fibrillation. Atrial fibrillation (AFib for short) causes an irregular heartbeat.
In some people with AFib, PACs are thought to trigger the onset of this arrhythmia. Some studies link PACs (especially more than 76 PACs per day) with an increased risk of developing atrial fibrillation, stroke, or heart disease.
Unless PACs are thought to trigger AFib flare-ups, they rarely require treatment. However, in some cases treatment is considered.
The best way to treat PAC is to avoid substances that appear to make symptoms worse.
Medications and Procedures
In rare cases, PACs are very uncomfortable, so it may be worth trying to control them with medication or other interventions.
Beta-blockers may help reduce PAC symptoms in some people and are often recommended as a first step.
Antiarrhythmic drugs may also be effective in reducing PAC, but these drugs are often very toxic. PACs are not recommended unless they cause severe and intolerable symptoms.
Ablation, a procedure to remove a layer of tissue from the atrium, is another possible approach, but this form of treatment is invasive and carries the risk of serious complications. Ablation of PACs is commonly used in patients whose PACs are symptomatic, resistant, very frequent, and/or cause more severe arrhythmias, such as Afib.
Ablation therapy for atrial fibrillation
Premature atrial contractions are the most common type of arrhythmia. Many people with PAC have no symptoms at all. Others may experience a jumping sensation or an unusually strong heartbeat. PACs themselves are generally harmless, but they may be associated with increased cardiovascular risk in some people, in which case treatment may be recommended.
If you’ve been told you have a PAC, don’t worry, you’re the majority. Almost everyone has it, and rarely requires treatment. If PAC is causing heart palpitations or you are concerned about your risk of heart disease, discuss treatment options with your healthcare provider.