Atrial Fibrillation – Arrhythmia not as mild as we believe. What does it lead to and how to prevent it?

With Dr hab. Oskar Kowalski, MD, Chairman of the Heart Rhythm Section of the Polish Cardiac Society, and Dr. Ewa Jędrzejczyk-Patej from the Silesian Center for Heart Diseases in Zabrze, we discuss the risk of ischemic stroke in people with atrial fibrillation.

Atrial fibrillation (AF) is an arrhythmia, which consists in uncoordinated and rapid stimulation of the atria of the heart 350-700 / minute (the most important part of the heart – the ventricles – fortunately only some of the beats appearing in the atria at that time are transmitted, but the action of the ventricles happens anyway) in many patients it is rapid during arrhythmia). As a result of such electrical chaos, the work of the atria is practically completely impaired. During arrhythmias, their walls do not constrict and therefore do not pump blood into the ventricles. For the patient, the main symptom is an irregular (uneven, irregular) heartbeat, and therefore also an irregular heartbeat and, consequently, palpitations. In many cases, this arrhythmia is asymptomatic, and diagnosis is made only in the event of complications, including stroke. In developed countries (Europe, USA), about 1,5-2% of people suffer from atrial fibrillation, and because the incidence of this arrhythmia increases with age, the number of patients suffering from it has doubled in the last 50 years due to the aging of the population. disease. It has been estimated that around 6 million people in Europe suffer from AF, and the average age of patients is around 75 years. There is no precise data on the number of patients in Poland, but it should be assumed that it undoubtedly exceeds the level of 500.

Although in most cases this arrhythmia is not associated with an immediate life-threatening condition, it is not a benign arrhythmia as has been believed for many years. Atrial fibrillation may contribute to the occurrence of ischemic stroke or the development of heart failure.

Risk of ischemic stroke in patients with atrial fibrillation

A thrombus can form in the heart during atrial fibrillation. Its displacement into the arteries of the brain can lead to ischemia and, consequently, to a stroke. Compared to the general population (without arrhythmia), the risk of this complication is approximately five times higher. Atrial fibrillation strokes account for at least 15-20% of all strokes and are unfortunately more severe and result in a greater degree of disability. Based on the estimated data, it is estimated that this arrhythmia contributes to strokes in 15-20 thousand. Poles every year, and the risk of this complication also increases with age.

Methods of preventing stroke in patients with atrial fibrillation

Prevention of thromboembolic complications (because apart from a stroke, other organs may also be ischemic) is one of the most important elements in the treatment of atrial fibrillation. Each patient who develops this type of arrhythmia should be individually assessed using an appropriate scale for stroke risk and, if it is severe, treated appropriately. In most patients it is pharmacological treatment, and in selected cases (in patients unable to use anticoagulants for various reasons) surgical treatment is required. The type of treatment to be used is always decided by the doctor together with the patient.

Pharmacological treatment uses drugs that reduce blood clotting, so on the one hand they prevent the formation of blood clots in the heart during arrhythmias, but on the other hand, they may contribute to a higher risk of bleeding in the patient. Currently, there are two types of these drugs: older and newer generation drugs. The first group consists of traditional anticoagulants, the effectiveness of which in preventing strokes has been confirmed in numerous studies. Their disadvantage is, unfortunately, the need to individually determine the dosage based on the blood coagulation index. Patients using these drugs must therefore regularly perform blood tests (sometimes quite often) and the dose of the drug is adjusted each time based on the results.

Despite the long experience in using and determining the dosage, older generation drugs have a significant disadvantage. Due to the need to individually determine the dose of the drug after each blood clotting measurement, there is a risk that the patient taking too little of the drug is not protected against a stroke, or by taking too high a dose, he is at risk of bleeding.

New generation drugs are a breakthrough in anticoagulant therapy. Their use does not require regular blood tests and individual dosing – the patient uses the tablet once or twice a day, depending on the type of preparation chosen by himself and the doctor in charge. If you are taking new anticoagulants, the risk of overdosing is small – only if you have consumed too many tablets or if your kidney function has deteriorated significantly.

How is the treatment effective and is it safe for the patient?

Today we know from research conducted around the world that the new anticoagulants are as effective in preventing stroke as the older drugs (and some of them, such as dabigatran 2 x 150 mg, may be even more effective). At the same time, they are much more convenient to use, because there is no need for regular and frequent blood tests. The patient does not have to determine their dosage individually, so the risk of using too little or too much is negligible. It should be added that all available formulations of new anticoagulant therapies do not increase the risk of haemorrhage dangerous for the patient, and some of them (e.g. dabigatran in a dose of 2 x 110 mg or apixaban) even seem to reduce such risk compared to older generation drugs.

Of course, these drugs are not entirely without drawbacks. Minor bleeding, e.g. from the gastrointestinal tract, may appear more often. They are also significantly more expensive than traditional drugs. They cannot be used in patients with renal insufficiency (a weakened kidney function could lead to a reduction in elimination of the drug from the body, and thus to its too strong effect). Each time the decision to include any of the new anticoagulants in the treatment must, of course, be preceded by a thorough analysis of the patient’s condition by the attending physician.

The importance of the reversal of the action of new anticoagulant therapies

While the risk of overdose with the new anticoagulant therapies is minimal, there are emergencies where rapid reversal of the drug is required, such as in the event of bleeding or urgent surgery. While in the case of the use of older generation drugs, we have drugs that quickly reverse their action (and thus restore efficient blood clotting), until recently, unfortunately, there was no antidote to newer generation drugs. The blood coagulation of the patient using the preparation returned to normal only when the drug stopped working, i.e. after about a day. In emergency situations, it was necessary to use preparations containing blood clotting factors (taken from blood donors). Due to the method of obtaining them, such preparations are available only in specialized institutions. Currently, however, a preparation that reverses the action of one of the new anticoagulants, i.e. dabigatran, has been introduced, also in Poland. It is used intravenously and may be available in any hospital setting. This means that it is significantly safer to use this medicine as in an emergency it is possible to reverse the effect of the medicine almost immediately. It is expected that such an antidote will be available for any type of anticoagulant in the future.

Surgical treatment of atrial fibrillation

Removal of arrhythmias can be successfully performed in a significant proportion of patients. Such a procedure is ablation of atrial fibrillation. In most cases, it is performed using the percutaneous technique, that is, by puncturing the vessels in the groin, most often only under local anesthesia. It consists in obtaining electrical isolation of places in the left atrium of the heart where pulmonary veins enter it. These sites have been shown to be most responsible for arrhythmias. Of course, ablation procedure does not guarantee the complete elimination of arrhythmias, but it is currently the only available treatment method that gives such a chance. The effectiveness of the procedure depends on many elements: the patient’s age, accompanying diseases, dimensions of the heart, and especially the atria, and it is discussed with the patient each time before the final decision about the procedure. In relatively young people and without other diseases, it can reach over 80%.

Some people who are unable to take anticoagulant medications because of recurrent bleeding may undergo a so-called closing the left atrium appendage. After successful surgery, the use of strong blood clotting drugs can be discontinued without significantly increasing the risk of stroke.

Hypertension as a disease of civilization? How to fight cholesterol? How do plant sterols affect cholesterol? You will learn all of this in the supplement “Heart – take care, control, but”, which is published on April 20 together with “Gazeta Wyborcza”. The add-on is available online especially for our readers.