What Is Atrial Fibrillation?

Atrial fibrillation, also called AFib or AF, is the most common type of heart arrythmia. In atrial fibrillation, the heart rate typically becomes fast and irregular. Atrial fibrillation is usually not immediately life-threatening, but if it remains untreated, it may increase the risk of stroke and cause heart failure, among other things.

Common symptoms of atrial fibrillation include irregular heartbeat, anxiety, dizziness, fatigue and reduced performance. There are individual differences and variation in the occurrence of symptoms. Atrial fibrillation is often asymptomatic (without any symptoms).

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Types of Atrial Fibrillation

Atrial fibrillation can be divided into four main types based on recurrence and duration:

  1. Paroxysmal atrial fibrillation: an episode with short duration, lasting a couple of minutes or hours, after which the heart rate returns to normal on its own.
  2. Persistent atrial fibrillation: an episode that lasts over a week and does not stop on its own. In this case, treatment with electrical or pharmacological cardioversion is needed to restore normal heart rhythm.
  3. Long-term persistent atrial fibrillation: an episode typically lasting over a year, when invasive treatments may be considered to restore normal heart rhythm.
  4. Permanent (chronic) atrial fibrillation: normal heart rhythm cannot be restored despite treatments. In this case, atrial fibrillation is accepted as a permanent condition and attempts to convert AFib to normal sinus rhythm are no longer pursued.

In addition to these classifications, the terms “lone atrial fibrillation” and “transient atrial fibrillation” are used. They refer to the occurrence of atrial fibrillation in people who do not have heart disease but who experience an episode of AFib triggered by some transient factor.

Normal Heart Rhythm

The normal rhythm of the heart is called sinus rhythm, with a heart rate at rest from 60 to 80 beats per minute. The rhythm originates from an electrical impulse generated in the sinus node in the wall of the right atrium. The sinus node acts as the natural pacemaker of a healthy heart and generates an electrical impulse stimulating the heart to contract to pump blood. As a result of the depolarization of heart muscle cells (myocardial cells), the electrical impulse generated travels from the sinus node through the atria. This makes the atria contract and pump blood in the ventricles. The impulse then moves through the atrioventricular node (AV node) in the septum, which is the wall dividing the left and right ventricles of the heart. The impulse now travels through two branches: one that goes to the right ventricle and the other to the left ventricle. These two main branches divide further into a system covering the entire heart muscle. As a result of the electrical impulse, the heart muscle contracts and pumps blood from the heart into the circulation system. After the contraction period (systole), the contraction ends and the heart muscle returns to a period of relaxation. This is called diastole. The sinus node accelerates the heart rate when needed, for instance, when there is physical exertion.

Onset and Mechanism of Atrial Fibrillation

Atrial fibrillation is the most common type of heart arrhythmia affecting no less than 25% of the global population at some time during their lives. In atrial fibrillation, more rapid electrical activity replaces the normal rhythm of the heart and tries to make the heart contract 450–600 times per minute. The heart muscle in the atria cannot contract this fast and ends up quivering (or fibrillating, from which the term atrial fibrillation is derived).

As the electrical impulse in atrial fibrillation reaches the AV node between the atria and the ventricles, it slows down the rhythm on its way to the ventricles. Thus, in newly onset atrial fibrillation, the heart rhythm conducted to the ventricles is clearly increased and usually irregular. The rapid heart rhythm in atrial fibrillation stimulates the AV node. Thus, the electrical impulses sent by the atrium randomly travel into the ventricle, resulting in an irregular heart rate. The heart rate can be, for instance, 130–160 beats per minute. Especially in paroxysmal atrial fibrillation, the heart rate is rapid, as described above. However, over time (for instance, over a few months), the heart rate in atrial fibrillation often slows to 80–120 beats per minute. There may be considerable individual variation in heart rate during atrial fibrillation.

Predisposing Factors for Atrial Fibrillation

Age is the most significant predisposing factor for atrial fibrillation. In people over 50 years of age, the risk of atrial fibrillation more than doubles every 10 years. In addition to age, the predisposing factors can be divided into cardiac and noncardiac. The most significant cardiac factors are high blood pressure, heart failure, valvular heart disease and coronary artery disease (CAD). Of noncardiac factors, diabetes, obesity, sleep apnea, thyroid disease, chronic pulmonary diseases and unhealthy lifestyle particularly predispose patients to atrial fibrillation.

In individuals who do not have heart disease, transient atrial fibrillation can be triggered by the following factors, among others: viral pericarditis or myocarditis, drug abuse, drinking too much coffee or energy drinks or drinking too much alcohol. In these cases, the heart rhythm often returns to normal when the triggering factor is removed or treated.

Even though atrial fibrillation is an arrhythmic condition that requires treatment and attention, it can also be a symptom of another heart disease, such as heart failure, valvular heart disease or coronary artery disease. When atrial fibrillation occurs, it is vital to seek medical assistance. Only this makes it possible to find the underlying causes and enables proper treatment.

Detection of Atrial Fibrillation

To diagnosis atrial fibrillation, an electrocardiogram (ECG)is used. For this reason, it is difficult to diagnose paroxysmal atrial fibrillation, as the heart rhythm often returns to normal before any detailed examinations can take place. Considering this, smart technological devices for home use to detect AFib (blood pressure meters, mobile applications and smartwatches recording heartbeat and rhythm)can be a major help in detecting atrial fibrillation.

Read more about how to detect atrial fibrillation by yourself

Is Atrial Fibrillation Dangerous?

Atrial fibrillation is dangerous. It is not immediately life-threatening like ventricular fibrillation or myocardial infarction, but persistence over a long time makes it dangerous. Long-term persistent atrial fibrillation is a predisposing factor for stroke and heart failure. The fact that atrial fibrillation can be completely asymptomatic makes it even more dangerous. Research shows that up to 40% of diagnosed AFib cases are asymptomatic. It is essential that atrial fibrillation is not left untreated and that the patient seeks medical attention. This enables the establishment of an individual treatment strategy.

During atrial fibrillation, the atria do not contract properly, and due to this, blood may pool there. When blood has the opportunity to pool, it also has the opportunity to clot. At some point, blood clots may be pumped out of the heart and travel through the bloodstream. This does not happen immediately: only when atrial fibrillation has persisted for longer than 48 hours. When a blood clot travels to the brain, it blocks blood vessels, thus disturbing normal circulation in the brain. In any area of the brain where normal blood supply is blocked, the lack of oxygen and nutrients starts to damage brain cells .

Untreated long-term persistent atrial fibrillation can impair heart function and predispose the patient to heart failure. Research shows that atrial fibrillation can increase the risk of heart failure up to nearly 400%. Congestive heart failure is not a disease as such, but a syndrome, in which the heart is unable to pump enough blood to meet the demands of the body. As the heart is unable to pump blood efficiently enough, the oxygen supply in the body deteriorates. Symptoms first appear during exercise, but as heart failure progresses, they can occur during light activities and even at rest. Studies show that almost half of all patients who suffer from heart failure die within five years from the onset of symptoms. There is individual variation caused by several underlying factors. Atrial fibrillation is only one factor that predisposes patients to heart failure. Other predisposing factors include cardiovascular disease, previous myocardial infarction and high blood pressure.

Symptoms of Atrial Fibrillation

There is considerable variation in the symptoms of atrial fibrillation, ranging from a completely asymptomatic condition to severe symptoms. Many studies have been conducted on the prevalence of symptoms. According to several studies, more than half of all people with atrial fibrillation do not recognize any symptoms or are asymptomatic. In fact, a study conducted at Turku University Central Hospital shows that over one third of patients who were hospitalized urgently because of a stroke had completely asymptomatic atrial fibrillation. Thus, stroke was the first manifestation of atrial fibrillation in these patients.

The most typical sensations associated with atrial fibrillation include irregular heartbeat, palpitation, anxiety, dizziness, fatigue and reduced performance. In long-term persistent atrial fibrillation, the sensations are often mild, and some people do not notice them at all. Paroxysmal atrial fibrillation can be very disturbing and cause anxiety. It is understandable that the first episode of atrial fibrillation may feel rather frightening.

Prevalence of Atrial Fibrillation

It is estimated that there are 230,000 patients diagnosed with atrial fibrillation in Finland. In reality, the number of people with atrial fibrillation is considerably higher, as the disease is often asymptomatic. Every year, about 11,500 people in Finland have their first stroke. Over 80,000 Finns (1.5% of the population) have suffered a stroke. About one third of these strokes relates to atrial fibrillation. Had atrial fibrillation been detected early, more people would have avoided stroke.

One in four people aged 40 years or above will have an episode of atrial fibrillation. The prevalence of atrial fibrillation increases rapidly with age. Studies show that 0.4% of people under 60 suffer from atrial fibrillation, but for those 75 or above, the prevalence is over 10%.

How Can I Detect Atrial Fibrillation?

There are two alternatives for detecting AFib at home: checking your pulse or using a monitoring device meant for consumers.

Checking your own pulse by hand is a cheap and easy way of finding out if your heart has a normal sinus rhythm. A good way of noticing irregular heart rate is to say out loud “now” every time your heart beats. The drawback of this method is that, if you notice an abnormal heart rhythm, it is impossible to say, which type of arrhythmia it is (extrasystolic beats, atrial fibrillation, atrial flutter, tachycardia or bradycardia). However, atrial fibrillation is the most common of significant arrhythmias.

When using an AFib home monitoring device, the most important thing is to ensure that it is a CE-certified medical device meant for detecting atrial fibrillation. This way, you can be sure that it has proved to be functional in demanding clinical trials and has been checked and approved by the authorities.

There is a wide variety of CE-certified devices, and their number is continuously increasing. These devices can be classified into the following categories: mobile applications using built-in sensors in smartphones, technologically advanced blood pressure meters and wearable smart devices (watches, wristbands, jewelry).

Examples of CE-certified devices for atrial fibrillation detection:

  • Solutions that measure heart movements: Mobile app CardioSignal (€4.17/month –€7.99/month depending on the chosen subscription period).
  • Blood pressure meters: Omron M7 Intelli IT Afib (about €130) and Microlife BP B6 (about €120).
  • Solutions that measure the electrical activity of the heart: Apple Watch Series 4 smartwatch or a newer version with ECG feature (starts at about €450), Withings Move ECG (about €130).
  • Solutions that measure blood flow: smart watches/smart bands, for instance, Fitbit Versa (starts at about €110) or Apple Watch Series 3 or a newer version (starts at about €230), or mobile applications measuring blood flow on the tip of the finger.

Different devices have different benefits, so finding the best solution depends on several factors. If a person is used to regular blood pressure monitoring, the use of a technologically advanced blood pressure meter may be a good choice. The drawback of this method is the relatively high purchase price of the device. In addition, the device is not as easily portable as the other solutions.

Mobile applications are the cheapest and easiest way of getting an AFib detection solution. As smartphones have become widespread, almost everyone has a device in their pocket, which is suited for doing measurements. All that the user needs to do is download a mobile application from the App Store or Google Play Store. The application can then perform the measurement. All data collected are analyzed on the cloud service of the application. The analysis result is available immediately. Mobile applications do not enable continuous monitoring. For this reason, it is recommended to take regular measurements, for instance, in the morning and evening.

The Finnish CardioSignal application uses the built-in movement sensors of the smartphone. These sensors measure the micromovements of the chest caused by the heart. This technique is called gyrocardiography (GCG). Clinical trials have shown that it is extremely accurate and enables self-monitoring of heart movements.

There are also mobile applications that utilize photoplethysmogram (PPG). These applications try to estimate heart functions based on the detection of blood flow. The use of a PPG mobile application requires that the user places their fingertip over the camera lens and flashlight and tries to hold the finger steady while pressing for 1 to 2 minutes. Because peripheral circulation typically deteriorates with age and the measurement is technically demanding, it is a challenging technique for the elderly.

A smartwatch can be constantly worn on a user’s wrist to take measurements as needed. However, the purchase price is considerably high, and the consumer’s decision to buy is usually not only based on the AFib detection feature but also on other smart features of the device. Regarding smartwatches, it is useful to know that their continuous monitoring technique is often based on a rather approximate heart rate monitoring from the user’s wrist using LED light and the PPG technique. To ensure successful measurement and receive a result, the user should preferably be at rest. In addition, the smartwatch band should be tightened properly to ensure close contact with the skin. When the user moves during normal everyday activities, these devices cannot reliably estimate heart rate. This is discussed in the user instructions of the devices. In addition to the PPG technique, some smartwatches provide the user with a single-lead ECG. The user needs to initiate the recording and keep their fingers on a certain part of the device.


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What Should I Do If I Have Atrial Fibrillation?

The diagnosis of atrial fibrillation and treatment decisions are always and solely made by a physician. If you suspect you might have atrial fibrillation, please contact your doctor. A confirmed diagnosis of atrial fibrillation and any treatment decisions made by the physician are always based on a 12-lead ECG during the arrhythmia. The measurement is done either at a clinic or laboratory with an ECG device or with a wearable Holter monitor, which needs to be worn for a few days. Paroxysmal atrial fibrillation is difficult to verify, as the patient’s rhythm has often already returned to normal by the time an ECG is performed. It is also possible that no paroxysmal atrial fibrillation episodes occur while wearing the Holter monitor.

To find the right treatment, the patient is interviewed, a physical examination is carried out, and an ECG recording is taken. In addition, blood tests, pulmonary imaging, structural heart imaging and stress tests may be carried out as needed. It makes it considerably easier for the doctor if the patient is able to provide a detailed description of symptoms. If possible, it is useful to note the following before visiting the doctor:

  • findings of heart monitoring devices used at home
  • how do symptoms feel, how long do they last, when do they start and disappear?
  • in which situations do symptoms occur and how often?
  • is the heart rate irregular and how fast is it?

Treatment of Atrial Fibrillation

The treatment of atrial fibrillation is divided into three categories:

  • Prevention of stroke
  • Control of arrhythmia (prevention of arrhythmia vs. heart rate control)
  • Control of underlying diseases and predisposing factors

The prevention of atrial fibrillation focuses on minimizing the risk of thrombosis and on restoring normal sinus rhythm. An episode of atrial fibrillation can go away on its own or with medication in a few days. If this does not happen, electrical cardioversion for restoring normal heart rhythm may be conducted under brief general anesthesia. If atrial fibrillation has continued over 48 hours, anticoagulant therapy (blood thinning drugs) is initiated in addition to electrical cardioversion. Treatment with anticoagulants is continued for one month because of an increased risk of thrombosis (the formation of a blood clot within a blood vessel).

In long-term treatment, underlying diseases and the severity of atrial fibrillation are considered. It is also essential to take care of predisposing factors, such as high blood pressure and obesity.

Atrial fibrillation tends to recur and may even become permanent. Thus, either rate control or rhythm control can be selected as a treatment strategy. In rate control, no attempts are made to restore or maintain normal sinus rhythm, and AFib is accepted as a permanent condition. This is often a good option in elderly patients. Rhythm control usually requires the use of antiarrhythmic drugs, and the treatment decision is made individually for each patient.

Because atrial fibrillation tends to recur, attempts are usually made to maintain normal rhythm with medication. Prophylactic drugs are selected individually for each patient. Treatment with beta blockers can be initiated in primary care, but antiarrhythmic drugs can only be initiated under the guidance of a specialized physician. In the prevention of atrial fibrillation, carefully planned anticoagulant therapy has a positive effect on the prognosis. When the need for medication is evaluated, a so-called CHA₂DS₂-VASc score is used. Either NOACs (apixaban, dabigatran, edoxaban, rivaroxaban) or warfarin can be used for the prevention of thrombosis. Aspirin is no longer regarded as an appropriate drug for reducing stroke risk associated with atrial fibrillation.

What is the CHA₂DS₂-VASc Scoring System?

The CHA₂DS₂-VASc scoring system helps in determining the right treatment for patients suffering from atrial fibrillation. It also aims at evaluating stroke risk. It contains many yes–no questions, and each of them gives a score. The structure of the scoring is as follows:

Factor Score
C Congestive heart failure 1
H Hypertension 1
A₂ Age >=75 years 2
D Diabetes mellitus 1
S₂ Prior TIA or stroke 2
V Vascular disease, for instance cardiovascular disease 1
A Age 65-74 years 1
Sc Sex (female), when aged >=75 1

The patient’s total risk score is the sum of all the factors. Based on this, the need for medication is evaluated as follows:

Total score Treatment
Score 0, small risk No need for medication
Score 1, moderate risk No medication or oral anticoagulant therapy. The physician makes the decision in individually for each patient. The medication might not be given if there is a high risk of bleeding or another risk factor (for instance blood pressure) has been treated well and the patient does not have other minor risk factors (for instance smoking, dyslipidemia or renal failure).
Score 2 or more, high or very high risk Oral anticoagulation therapy is indicated almost without exception.

Living with Atrial Fibrillation

Atrial fibrillation is usually a chronic disease and needs to be monitored regularly. Properly treated, it does not have a significant effect on the quality of life of the patient: one just needs to learn to get along with it.

Over time, paroxysmal atrial fibrillation tends to become permanent. However, this is not the case for everyone, and it may take years. If this happens, meaning that cardioversion or other procedures for restoring normal rhythm are no longer used, atrial fibrillation treatment still continues. Treatment involves selecting the correct medication. In Finland, there are tens of thousands of patients with permanent atrial fibrillation receiving anticoagulant therapy. Despite this, they manage to live rather normal lives. Permanent atrial fibrillation may feel uncomfortable at first, but the body gets used to it within a couple of months, and symptoms are relieved.

Long-term persistent atrial fibrillation is followed up regularly. Follow-up visits aim at ensuring that the medication and selected treatment are appropriate. The frequency and content of follow-up visits depend on the patient. For instance, permanent atrial fibrillation tends to slow with age. In that case, medication given to slow heart rhythm can be reduced or stopped. Follow-up is based on regional chains of care, organized as outpatient and specialized care.

You can also manage atrial fibrillation yourself in several ways. Healthy lifestyle plays a key role. Do not let atrial fibrillation limit your life: exercise and enjoy healthy food and relationships with your friends and family. Avoid factors that appear to cause your atrial fibrillation episodes. Predisposing factors of atrial fibrillation include poor sleep, drinking too much alcohol, stress, other illnesses, heavy meals and consuming too much caffeine.

Lead a healthy lifestyle and remember to relax and sleep well.


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