What is atrial fibrillation and what types are there?
Atrial fibrillation is the most common sustained arrhythmia today (with an estimated prevalence in the adult population of between 0.4 and 2%). Its high frequency is associated with the aging of the population, and in elderly patients it leads to a significant increase in mortality due to cardiovascular problems.
It is an alteration of the usual conductivity of the heart, called sinus rhythm, when the atria do not contract correctly and the ventricles contract irregularly and excessively fast, preventing the heart from functioning. It is usually associated with mitral valve disease, but it can also arise in isolation or linked to other diseases. It is distinguished by uncoordinated atrial contraction rhythm. It can generate thrombi and embolisms, and major cardiovascular complications such as stroke.
It can manifest itself paroxysmally (short, self-limited episodes), persistently (longer episodes that usually require medical action to eliminate) and permanently or chronically.
What are the causes?
The mechanism of arrhythmia production is based on the uncoordinated activation of the left atrium without effective contraction. This results in pulsations that are usually faster than usual, and the possibility of thrombi (blood clots) forming inside the atrium.
Atrial fibrillation can appear in hearts with certain cardiac pathologies such as: mitral valve disease, coronary artery disease, pericarditis, congenital heart disease, among others; associated with other diseases such as arterial hypertension, thyroid disorders, etc., or even when there is excessive alcohol consumption.
But it can also appear in apparently healthy people who, in principle, do not have any cardiac pathology, and in these cases it is usually of unknown cause, and at the same time it usually has less serious consequences for health than when it occurs in diseased hearts.
What symptoms does it present? How can we detect that it is happening to us?
Patients usually present palpitations, which is the subjectively abnormal sensation of the heartbeat, which can be perceived as strong beats, fast beats, irregular beats or rapid beats; a feeling of choking, chest pain, fatigue, dizziness, fainting, etc. In general, atrial fibrillation makes it impossible to perform the simple tasks of daily life.
Throughout the course of the disease, the patient may experience periods with and without symptoms, because, over time, the palpitations may even disappear. This is essential because it is possible to be in danger without feeling any discomfort.
Occasionally, a patient is found to have atrial fibrillation because he or she suddenly suffers cerebral ischemia or stroke (transient or permanent), whose clinical manifestations (difficulty in moving half of the body or in speaking or both) may disappear within 24 hours or remain permanent (or even lead to death). Strokes are due to the formation of thrombi in the atrium, which can detach and migrate through the bloodstream to the brain, occluding an artery, with the consequent lack of irrigation in a part of the brain, which is what we call cerebral embolism.
It is easily detected by means of an electrocardiogram (ECG). The presence of structural heart disease must then be ruled out by means of an echocardiogram.
The best technique for detecting thrombi in the left atrium is transesophageal echocardiography (TEE), which also provides information on the right time to perform electrical cardioversion.
Can it be prevented in any way?
Recommendations to patients with atrial fibrillation include all of the following:
- Control blood pressure. Blood pressure is the main cause of atrial fibrillation. For this reason, it is especially essential to maintain strict control of it.
- Moderate alcohol consumption. Alcohol is a trigger for episodes of atrial fibrillation. There are even people who only develop it after a heavy alcohol intake. Moderate consumption of alcoholic beverages is always advisable, but if you also have another heart disease, you should consult a specialist in cardiology about its consumption. Alcohol may be absolutely contraindicated.
- Reduce stimulants. Coffee, tea, cola drinks… are stimulants capable of generating atrial fibrillation, so their consumption should be ruled out or reduced.
- Quit smoking. Tobacco is always harmful to health and in people with atrial fibrillation even more so because it contains stimulants, such as nicotine, which can cause a crisis. Quitting smoking is the ideal way to reduce episodes of atrial fibrillation, as well as the possibility of suffering cardiovascular diseases (myocardial infarction, stroke…) or non-cardiovascular diseases, such as different types of cancer. To overcome addiction more easily, it is advisable to consult your doctor. Many health centers have specialized smoking units that can help.
- Moderate exercise. The practice of intense and prolonged physical exercise can impede the full effectiveness of atrial fibrillation treatment and increase the risk of recurrence. This does not mean that the patient should adopt a sedentary lifestyle. Walking every day and moving around is important, but avoiding long-distance running, long bicycle rides or sports that involve a great deal of cardiovascular effort.
What is the most effective treatment?
There are two fundamental aspects: first, control of the arrhythmia, either its reversion to normal sinus rhythm of the heart by cardioversion or control of the pulsations by means of drugs, and second, prevention of cerebral embolisms by means of anticoagulant medication (such as sintrom, the oldest and best known, or other more modern anticoagulant drugs, with proven effectiveness and safety).
Cardioversion consists of applying a brief electric current to the chest by means of a defibrillator, after sedation of the patient. This technique is very safe and usually reverses the arrhythmia in 80-90% of cases, but it does not prevent its recurrence, which can only be prevented by drugs or ablation.
There is a potentially curative treatment, called pulmonary vein ablation, which allows lesioning the arrhythmia-producing foci with a low-voltage energy current via radiofrequency, thus eliminating the arrhythmia. Due to its technical difficulty, risks and therapeutic success (around 70%), this method is usually reserved for patients with relapses despite drug treatment.
When the risk of embolism is considered high, the specialist recommends that the patient be treated with anticoagulant drugs. When the risk is low, it can be easily treated with aspirin (acetylsalicylic acid) alone or even without medication. These aspects can only be assessed by your physician.