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This page will provide you with a comprehensive overview on the etiology of premature atrial contractions, the symptoms and diagnosis of premature atrial contractions, the cause of premature atrial contractions and the treatment options available for premature atrial contractions. We sincerely hope that our website helps to further your understanding on the topic of premature atrial contractions. If you have further questions, please contact a healthcare professional.
What Are Premature Atrial Contractions (PAC)?
Premature atrial contractions (PAC), also referred to as atrial premature atrial complexes, are amongst the most common forms of arrhythmias. Like the name suggests, the cause of premature atrial contractions is due to the premature discharge of electrical impulses in the atrium. Importantly, during normal sinus rhythm the heart is regulated by electrical impulses in a sinusoidal node. The sinusoidal node is simply a section of nodal tissue located in the upper wall of the right atrium; it functions as a pacemaker in the heart. This regulation is crucial in determining both the contraction rate and the overall functionality of the heart. When another area of the atria depolarizes before the sinoatrial node, it triggers a contraction, and thus, results with premature atrial contractions. Therefore, a premature atrial contraction is premature because it occurs earlier than the next regular beat is scheduled to.
The cause of premature atrial contractions is important in classifying it because it can be either unifocal or multifocal. When the cause of premature atrial contractions from a single ectopic focus, each PAC is identical and it is unifocal. In contrast, when the cause of premature atrial contractions arise from two or more ectopic foci there are multiple wave morphologies and it is considered multifocal.
Overall, there are four main characteristics of premature atrial contractions:
1. They are premature; they occur earlier than you would expect in a regular well-coordinated normal heartbeat.
2. They are ectopic; they originate outside of the SA node, and thus, the wave pattern morphology on an EKG would be different.
3. They are narrow complexes. Typically when the heart contracts, the atrial impulse propagates through the atrioventricular node and into the cardiac ventricles at a specific time during the cycle. However, when the beat is premature the impulse may reach the atrioventricular node during the refractory period (earlier), and thus, creating a different wave pattern that is narrower. This is different from premature ventricular contraction (PVC), which is considered a wide complex, because it eventually uses normal conduction systems to spread to the ventricles, and therefore, is generally not as dangerous.
4. There is a compensatory pause after the premature atrial contraction. The extra atrial action potential causes the sinusoidal node to become refractory to generating its next scheduled beat, and thus, it must “skip a beat” to try and normalize.
Symptoms of Premature Atrial Contractions
Premature atrial contractions are often completely asymptomatic and require the use of Holter monitoring to detect them. However, in some cases the symptoms may include: palpitations (a noticeably rapid, strong, or irregular heartbeat), the feeling of a “missing” or “skipping” heartbeat, and sometimes even the urge to cough due a strong contraction. A patient may describe this feeling as if their heart has “stopped” while others may describe a sensation of “flip-flop.” Regardless, it is important to note that these symptoms are common amongst many other related cardiac dysfunctions and are prevalent in both young and elderly healthy individuals; the presence of these symptoms alone do not constitute a medical emergency.
On the contrary, it is important to consult a health care professional if these symptoms persist because the symptoms of premature atrial contractions are fairly general, and thus, they may point to a more significant underlying condition. One specific example of a common condition is premature ventricular contractions (PVC). Since the symptoms of premature atrial contractions are often virtually indistinguishable from those of premature ventricular contractions (a potentially more serious condition), it is important for a medical professional to properly diagnose it.
Occasional Premature Atrial Contractions Vs Frequent Premature Atrial Contractions:
Although anybody who is concerned with their health should consult a health care professional, it is important to note that occasional premature atrial contractions are not dangerous. This is because occasional premature atrial contractions are also isolated premature atrial contractions, meaning they do not occur in a repetitive fashion. Typically if a person has isolated premature atrial contractions, they have no reason to be concerned as it does not pose a health risk. Notably, even a palpitation in the chest and neck, which is often described as a “thump,” is common in healthy individuals; the body can easily make mistakes in its regulation. The time to be concerned is when there are frequent premature atrial contractions that cause severe discomfort to an individual. This is because frequent premature atrial contractions suggest that the heart is struggling in regulating its activities.
Diagnosis of Premature Atrial Contractions:
Due to the fact that the symptoms of premature atrial contractions are general, a health care professional uses several evaluation methods to diagnose the patient, such as echocardiograms, a Holter monitor and blood tests. One important method is the use of an EKG (electrocardiogram). On an EKG a premature arterial contraction is characterized by an abnormally shaped P wave. This is because the premature beat initiates outside the sinoatrial node. The medical professional ultimately uses the associated P waves and their pattern characteristics to compare it to a normal sinus rhythm, and thus, is able to determine how the is heart beating relative to a normal heart.
What Are The Causes of Premature Atrial Contractions?
Although the exact cause of premature atrial contractions in healthy individuals is unclear, there are many contributing factors that have been correlated to their prevalence.
• Other stimulants
• Valve disorders
• Underlying heart disease
• Abnormal blood levels of magnesium or potassium
• Previous myocardial infarct
• Digitalis toxicity
It is important to note how general some of these factors are, and as a result, how they can easily contribute to isolated premature atrial contractions.
Treatment of premature atrial contractions
The treatment of premature atrial contractions is often geared towards removing the symptoms associated with the condition. Since most of the time it is benign, treatment is optional and it is more important to teach various coping mechanisms in conjunction with reassurance. However, when required the medications commonly used are beta blocker or calcium blockers.
Overall, premature atrial contractions is not a major health risk, but if you would like further information please contact your local healthcare professional.