Atrial fibrillation is a widespread disease – you should know that

A fast beating heart, shortness of breath, a feeling of pressure and tightness in the chest – such symptoms can be a sign of atrial fibrillation. The most common cardiac arrhythmia – in Switzerland about one percent of the population is affected, but considerably more with increasing age – can also occur without symptoms. Undetected and untreated, atrial fibrillation is not harmless; it can have serious consequences, such as stroke or heart failure.

It is the most common form of cardiac arrhythmias. The electrical signals that lead to the contraction of the heart muscle no longer propagate properly in the heart. The normal heart rate (60 to 100 beats per minute) occurs when the natural pacemaker, the sinus node in the wall of the right atrium, generates the electrical impulses. These then spread like a wave through the two atria and make them beat. The impulses are then sent via the AV node – which is located at the transition from the atria to the ventricles – to the musculature of the ventricles.

In atrial fibrillation, the normal heart rhythm is disturbed; the atria no longer beat regularly, but too quickly, irregularly and uncoordinated. The electrical signals circulate in the atria, which are stimulated at a frequency of 350 to 600 times per minute – they vibrate or flicker. During this “electrical thunderstorm,” the function of the sinus node is released and the AV node sends the arrhythmic signals to the ventricles of the heart.

The atria no longer provide sufficient pumping capacity and no longer help to fill the ventricles with blood – their stroke volume is reduced by about a fifth as a result. However, they continue to pump blood into the circulatory system, albeit more irregularly.

Atrial fibrillation usually starts with infrequent, short episodes. Longer episodes may occur over time, or even permanent atrial fibrillation. Depending on the duration, there are four types:

Atrial fibrillation can show several symptoms: The most common sign is palpitations, which can be felt in the chest or throat. The heart usually beats faster and more irregularly than normal – instead of a resting pulse of about 60 to 90 beats per minute, the frequency is 120 to 160 times per minute; in some patients even up to 200 times.

Other possible symptoms include a feeling of tightness and pressure in the chest, a feeling of weakness, rapid exhaustion and drowsiness or even dizziness. However, more than a third to about half of those affected do not feel any symptoms, at least at the beginning of the disease. It therefore often goes undetected and untreated for a long time – sometimes a doctor accidentally discovers the condition during another examination.

There are several causes of atrial fibrillation. It often occurs due to aging and high blood pressure. Existing heart conditions can also lead to atrial fibrillation; such as heart valve defects, heart failure, inflammation of the heart muscle or coronary artery disease (CHD), where the coronary arteries are narrowed.

Beneficial factors also include obesity, diabetes, an overactive thyroid, and high alcohol or cocaine use. However, atrial fibrillation can also occur for no apparent reason in people with a healthy heart.

In the vast majority of cases, atrial fibrillation is not an acute threat to life; it is not life-threatening from the arrhythmia itself. However, in the long run, it can cause various secondary diseases. The increased risk of stroke due to a delayed blood clot is particularly dangerous. Because the atria no longer pump adequately, blood can pool there — especially in a part of the left atrium called the atrial aneurysm — and easily form clots. If a clot breaks off and travels through the bloodstream to the brain, it can clog a blood vessel and cause a stroke.

Atrial fibrillation accounts for 20 to 30 percent of strokes caused by vascular occlusion. The risk is even higher if risk factors such as high blood pressure or coronary artery disease already exist. It is especially high if there has already been a circulatory disorder in the brain.

Another secondary disease of atrial fibrillation is cardiac insufficiency (heart failure). Because the atria no longer pump properly, the rest of the heart has to work harder to supply the body with enough blood, oxygen and nutrients. Over time, this can overwhelm and weaken the heart. A pre-existing heart failure can be aggravated by atrial fibrillation.

Atrial fibrillation can be prevented to some extent by adopting a healthy lifestyle. This includes a healthy, balanced diet with plenty of fruits, vegetables, and whole grains. If you have high blood pressure, a low-salt diet is beneficial. Exercise is also important: about half an hour of moderate exercise per day of the week is ideal.

Since being overweight is a risk factor, maintain a healthy weight and try to reduce it if you are overweight. Other risk factors that are preventable include smoking and excessive alcohol consumption. For example, patients suffering from atrial fibrillation are less likely to have an episode if they largely abstain from alcohol.

If atrial fibrillation is detected and treated early, the risk of serious consequences or even death is reduced. On the one hand, the treatment aims to eliminate or at least alleviate the symptoms caused by the disturbed heartbeat. On the other hand, it should prevent stroke. Possible therapies include medications and, in more serious cases, surgery.

For example, drugs can only control the heart rate, ie lower the accelerated pulse and thus relieve the heart. This usually happens with a beta blocker. If this rate control is not sufficient, the normal heart rhythm must be restored with medication (antiarrhythmics) or with an electrical impulse (rhythm control). The main therapy for patients with atrial fibrillation who have additional risk factors is reliable blood thinning.

If drug therapies are unsuccessful, permanent rhythm control can be achieved using what is known as catheter ablation. The cardiologist enters the left atrium of the heart through the access in the groin. There it destroys the openings of the pulmonary veins, either by freezing or by high-frequency current. In doing so, it interrupts the conduction pathways that enable the electrical storm in the atria.

In addition to conventional catheter ablation, there is also the newer procedure of thoracoscopic ablation, which is also used in treatment-resistant cardiac arrhythmias. During this minimally invasive surgery, which takes about 90 minutes, the camera and instruments are inserted through small incisions in the chest wall. Unlike groin access, this procedure allows the cardiologist to use more energy (bipolar current) to scar the area of ​​the left atrium where the misfire originates.

“The resulting scar, which interrupts the misfires and thus the triggers of atrial fibrillation, is more durable,” says heart surgeon Sacha Salzberg, who mastered this special technique and opened a treatment center in Zurich last year (see infobox). During the procedure, the left atrial aneurysm – a small protrusion in the left atrium – is also closed with a clip. This greatly reduces the risk of stroke, as blood clots often form in the left atrial appendage and can enter the bloodstream. “The medication can be significantly reduced as a result, and the blood thinners, which previously prevented the stroke, can even be stopped completely and forever,” Salzberg explains.

sources:
• www.usz.ch/ickness/vorhoffimmern
• www.gesundheitsinformation.de/vorhofflimmmern.html
• www.swiss-ablation.com
• flexikon.doccheck.com/de/Vorhoffimmern
• de.wikipedia.org/wiki/Atrial Fibrillation

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