Atrial premature complexes are also called premature atrial contractions (PACs) and may cause heart palpitations or unusual awareness of your heartbeats. Palpitations may be heartbeats that are extra fast, extra slow, or irregularly timed. PACs occur when a beat of your heart occurs early in the heart cycle or prematurely.
PACs result in a feeling that the heart has skipped a beat, or that your heartbeat has briefly paused. Sometimes, PACs occur and you can’t feel them.
Premature beats are common, and usually harmless. Rarely, PACs may indicate a serious heart condition such as life-threatening arrhythmias.
When a premature beat occurs in the upper chambers of your heart, it is known as an atrial complex or contraction. Premature beats can also occur in the lower chambers of your heart.
These are known as ventricular complexes. Causes and symptoms of both types of premature beats are similar.
Symptoms of PACs
Most often, patients with PACs complain of palpitations. However, rather than reporting sustained racing heartbeat, they usually describe “missing” or “skipping” of the heartbeat.
Some patients even feel that the heart has “stopped” while others describe a sensation of “flip-flop.”
This is due to the fact that the PAC comes too early (prematurely) in the cardiac cycle to have resulted in an effective pulse or heartbeat.
Therefore, no heartbeat is felt until the next regularly-timed heartbeat occurs after a pause (so-called compensatory pause).
Incidentally, the beat after the PAC usually occurs with stronger contraction than usual and can be associated with an urge to cough.
Symptoms of PACs are virtually indistinguishable from those of PVCs as the physiological effects are identical.
What Causes Atrial Premature Complexes?
Your sinus node is an area of cells in the upper-right chamber of your heart. It controls the pace of your heartbeat through electrical signals.
Sometimes, signals from the ventricles (blood pumping chambers) cause a heartbeat that comes earlier than the natural, normal rhythm.
This is followed by a pause, and then a stronger second beat because the pause allows more time for blood to fill the heart chamber.
The cause of a premature beat is generally unknown. Most people who have PACs do not have heart disease (CardiacHealth).
Any of the following can cause premature beats to occur more frequently, making you more likely to notice them:
- caffeine consumption
- alcohol consumption
- fatigue or poor sleep
- medication that lists irregular heartbeat as a side effect (such as Dostinex, Requip, Wellbutrin, Xanax, Depakane, Advair, and more)
PACs could mean you have extra connections in your heart’s electrical system. These extra connections may cause your heart to occasionally beat irregularly.
Although this may be frightening or annoying, it is usually not dangerous unless you experience premature beats often, or they impact the quality of your life (CincinnatiChildren’s).
Sometimes, premature beats may be caused by an injury to your heart or underlying heart disease.
If you suddenly begin to experience skipping heartbeats, or if your heart feels different in any way, you should have your doctor examine you to rule out an underlying problem.
Underlying Conditions and Atrial Premature Complexes
Sometimes PACs can be a symptom of a more serious condition. If you notice your heart skipping beats, racing, or pounding in combination with any of these symptoms, seek prompt medical care.
You may have any of the following conditions:
- dangerous arrhythmias that may lead to stroke or heart failure
- heart disease, which may include infection, genetic defects, and narrow or blocked blood vessels
- hypertension (high blood pressure)
- the valve separating the upper chambers of your heart from the bottom chambers does not properly close
- ventricular tachycardia, a disorder that causes a rapid heart rate and may lead to heart attacks
If you experience premature beats occasionally without any other symptoms, the beats are probably not dangerous.
You should, however, seek treatment any time you notice a sensation in your heart that is new and has not been previously discussed with your doctor.
Diagnosing the Cause of Atrial Premature Complexes
Your doctor will probably first ask you some questions if you experience sensations of skipping, racing, or pounding heartbeats.
He or she may ask you what you were doing when you first noticed the symptoms. He or she will also likely ask about your medical history.
Indicators of heart disease, such as diabetes, high cholesterol, high blood pressure, being overweight, smoking, and having a family history of heart disease may warrant a more thorough exam, even if PACs are not accompanied by any other symptoms.
Your doctor will conduct a physical exam to detect indicators of underlying problems with the heart, and to monitor the function of your heart.
Procedures may include listening to your heartbeat, running blood tests to check your chemistry and cholesterol levels, and testing your blood pressure.
Your doctor will monitor your heart rate if your exam suggests you may have an underlying problem with your heart that is triggering PACs.
The pattern of disturbances can help your doctor understand what is causing them. This can be done with an electrocardiogram (a test that records the electrical activity of your heart, either during normal activity or during exercise).
You may also be instructed to wear a monitor for 24 to 48 hours or when symptoms occur. This monitor is worn under your clothing and records your heart rhythms as you go about your normal activities (MedlinePlus).
Consequences of PACs
The great majority of PACs are completely benign and require little if any treatment at all.
As mentioned above, in rare cases, PACs may be the only sign of underlying heart conditions and these should be ruled out with appropriate evaluations. However, PACs may change into
- Atrial Flutter
- Atrial Fibrillation
- Supraventricular tachycardia
Treatment of PACs
As most PACs are benign, treatment is optional and is usually geared toward alleviation of symptoms. Medications such as beta blockers or calcium blockers are often used but with mixed result.
Most important treatment, after ruling out severe underlying heart conditions, is patient reassurance and teaching of various coping mechanisms.
Preventing Atrial Premature Complexes
You can prevent benign (harmless) premature beats by avoiding substances such as recreational drugs, tobacco, alcohol, and caffeine (MayoClinic).
Also, try to practice cardiovascular exercise on a regular basis. Anxiety contributes to PACs, so reduce your stress levels, or discuss anti-anxiety medication with your doctor.
If you see a medical provider who is not familiar with your history, let him or her know to prescribe medications that are not likely to increase PACs.