Atrial fibrillation

With atrial fibrillation, the signals that regulate the heartbeat are disrupted. As a result, the heart frequently beats too quickly and inconsistently. This means that it is no longer able to pump as much blood around the body. Patients can feel faint or have symptoms such as clearly noticeable palpitations.

Atrial fibrillation is generally the result of another chronic condition, such as high blood pressure or coronary heart disease. In some cases, no clear cause can be found.

Atrial fibrillation is the most common form of cardiac arrhythmia. It is not immediately life-threatening but increases the likelihood of a stroke and can also weaken the heart in the long term.

The most common indication of atrial fibrillation is a clearly noticeable pounding heart (“palpitations” to use the medical term). This generally means that the heart beats faster and more irregularly than usual. The heart rate with atrial fibrillation can be far higher than the healthy resting rate of between about 60 and 100 beats per minute.

People with atrial fibrillation can also feel weak, dizzy or light-headed. However, up to 30 in every 100 people have no symptoms or only inconclusive symptoms that do not directly indicate atrial fibrillation. In some cases, people do not notice atrial fibrillation at all.

People who have atrial fibrillation alongside other heart conditions can also have additional symptoms. In the case of heart failure, for example, atrial fibrillation can noticeably reduce the heart’s performance. This can result in symptoms such as a shortness of breath and exhaustion, especially during physical exertion.

When the heart beats, the heart muscles rhythmically contract. The heartbeat is regulated by an electrical conduction system. The sinus node generates the signal for a new heartbeat. This is sometimes also referred to as the heart’s “natural pacemaker” and is a cluster of special cells in the wall of the right atrium. The electrical signals from the sinus node are transmitted along the conduction pathways to the atrioventricular node (AV node) and then on to the heart’s chambers. A normal heartbeat is also known as the sinus rhythm.

In people with atrial fibrillation, irregular electrical signals quickly spread through the upper chambers (atria). The sinus node is inactive during atrial fibrillation. As a result, the atria no longer contract and relax in a steady rhythm. Instead, they quiver rapidly and uncontrollably: they “fibrillate”.

The upper chambers of the heart normally help the lower chambers (ventricles) to quickly fill up with blood. They provide about 20% of the heart’s total pumping power. Atrial fibrillation reduces the heart’s performance. The lower chambers still pump blood through the body, but irregularly.

Atrial fibrillation can have several causes, the most common of which include:

• high blood pressure (hypertension)
• coronary heart disease
• heart attack
• heart failure (although this can also be the result of atrial fibrillation)
• heart valve defect

An overactive thyroid gland and certain medication can also cause atrial fibrillation.

In about a third of people with atrial fibrillation, no clear cause can be determined.

The likelihood of atrial fibrillation increases with age. According to estimates, about 2% of the total population and about 7% of over-65-year-olds are affected.

The risk factors for atrial fibrillation include high or frequent alcohol consumption, smoking, diabetes mellitus, high blood pressure, being heavily overweight and sleep apnea. Some of these risk factors are things that people can influence themselves.

Atrial fibrillation usually starts with rare, short episodes. Over time, longer episodes may occur or the fibrillation may persist permanently. There are four different types, depending on the length of the episodes:

• With “intermittent” (paroxysmal) atrial fibrillation, the heart rhythm usually returns to normal of its own accord and without treatment within about 48 hours. However, this type can also last for up to 7 days. Intermittent atrial fibrillation can occur as a one-off or repeatedly.
• Persistent atrial fibrillation lasts more than seven days.
• Long-standing persistent atrial fibrillation lasts for over a year.
• Permanent atrial fibrillation does not usually go away again.

Classification into these four types is limited in its meaning though as it is often not clear whether atrial fibrillation has occurred before or how long it has been present. It is also sometimes possible for permanent atrial fibrillation to recede and then return intermittently.

As atrial fibrillation does not always have symptoms, it can sometimes be detected by chance. For example, if the electrical signals to the heart are investigated due to another condition. Several investigative methods can be used to obtain a precise diagnosis, determine the causes and plan the treatment:

• Recording the medical history (anamnesis): the doctor asks about symptoms, pre-existing medical conditions, age and family history, as well as risk factors for heart conditions.
• Physical examination: for example, heart rate and blood pressure measurements.
• Electrocardiogram (ECG): ECGs can diagnose atrial fibrillation with a high degree of certainty. During this process, several electrodes are attached to the body to measure the electrical signals to the heart.
• Blood test: blood tests can be used to assess thyroid function among other things. An overactive thyroid gland or an overdose of thyroid medication can cause atrial fibrillation.
• Echocardiography: this procedure examines the heart using ultrasound. This makes it possible to check its pumping power, for example. However, echocardiography can also be used to detect more rare causes of atrial fibrillation, such as certain heart valve problems.

Other tests are mainly used to help plan treatment. For example, kidney and liver function can be determined because some medication is not suitable for people with kidney or liver weaknesses.

People with atrial fibrillation face several treatment decisions. First is the question of how the irregular heartbeat should be treated. The primary goal is to control the heart rate to an extent that alleviates the symptoms and takes the strain off the heart. Attempts can also be made to restore the heart’s normal rhythm (sinus rhythm).

There are two treatment strategies in this regard:

• Heart rate control: the excessively high heart rate is permanently reduced with medication, usually a beta blocker. No attempts are made to eliminate the atrial fibrillation.
• Heart rhythm stabilization: this strategy attempts to restore and stabilize the heart’s normal rhythm. This is usually done in a hospital by delivering controlled electric shocks. Treatment with medication usually follows to prevent relapses.

Heart rate control is usually the preferred treatment as it is less complicated and has a lower risk of side effects. Treatment to stabilize the heart’s rhythm is particularly useful in cases where heart rate control treatment is unable to sufficiently alleviate the symptoms.

People with atrial fibrillation also have to decide whether they want to take medication to reduce the risk of stroke and if so, which. Oral anticoagulants inhibit blood clotting and can reduce the risk of stroke very effectively.

More detailed information, for example on the prevention of strokes, can be found at gesundheitsinformation.de.

In rare cases, atrial fibrillation itself can be life-threatening and cause the blood pressure to drop sharply, for example. The heart’s rhythm can usually be quickly restored using controlled electric shocks.

If the heart beats normally, you do not generally notice it. Atrial fibrillation can change this: in many cases, patients feel that their heart is no longer beating properly. This is often so concerning that they consult their doctor. If atrial fibrillation is found, many people are initially very worried. However, this condition and its symptoms can usually be treated easily. Training courses can also be helpful for people with atrial fibrillation: they show how people can deal with the condition during everyday life and adjust their own medication.

However, many people with atrial fibrillation still have concerns. Some wonder if they need to be more cautious now or can still lead as active a life as usual, for example by doing sport. Studies suggest that those affected should not worry and indicate that moderate physical activity does not harm people with atrial fibrillation but can improve their fitness.