Atrial fibrillation is an arrhythmia in which the atria are activated in an uncoordinated manner, as if quivering, resulting in ineffective contraction of the atria and a faster, more irregular rhythm than the normal or sinus rhythm of the heart.
Atrial fibrillation is one of the most common types of arrhythmia. Its prevalence increases with age. In Spain, approximately 10% of the population over 70 years of age suffers from it, although sometimes they are unaware of it.
Types of atrial fibrillation
There are three types of atrial fibrillation:
- Paroxysmal, which is one that is triggered and subsides on its own. It has a variable duration, from seconds to days. It is usually the one that causes the most symptoms.
- Persistent, which does not cease on its own and requires medication or other procedures to restore normal sinus rhythm.
- Permanent, which remains chronically established.
Atrial fibrillation: symptoms
The symptoms of atrial fibrillation vary greatly from person to person. Some people even have no symptoms at all. Symptoms also vary depending on the cause that triggers atrial fibrillation.
The most common symptoms include
- tiredness
- fatigue
- shortness of breath, especially during physical exercise
- palpitations and rapid (tachycardia) and irregular heartbeat
- dizziness or even loss of consciousness
- chest pain or tightness
- need to urinate more frequently
Causes of atrial fibrillation
Occasionally atrial fibrillation can occur in apparently healthy people, without a specific cause being established. However, on many occasions there are causes or risk factors that can trigger or favor atrial fibrillation.
- Diseases of the heart valves, mainly mitral insufficiency and stenosis.
- Hypertensive heart disease, caused by chronic elevation of blood pressure.
- After cardiac surgery
- Heart failure, which can sometimes be the cause and sometimes the consequence of atrial fibrillation.
- Affections of the cardiac muscle
- Thyroid disease
- Severe infectious diseases
- Diseases of the respiratory system
- Sleep apnea
- Alcohol and drug abuse
Complications of atrial fibrillation
Embolism and heart failure are two of the most important complications of atrial fibrillation.
Embolism is due to the fact that the lack of contraction of the atria causes the blood to back up inside them, especially if they are enlarged, which favors the formation of thrombi or clots in them. If these become partially or totally detached from the interior of the atria, they are carried away by the blood stream and can occlude any artery.
As a result of the rapid and irregular heart rate, the heart does not work properly and the blood supply to the organs suffers, leading to heart failure.
Diagnosis of atrial fibrillation
Atrial fibrillation does not always present symptoms and may be found by chance during a medical examination. It can also be diagnosed after an embolic complication.
The interrogation and physical examination can provide guidance. The electrocardiogram will be definitive when the arrhythmia is present. A 24-48 hour ECG recording (Holter) will provide information on the heart rate over the course of a day and whether the therapeutic measures used to control it are effective. In the case of suspected paroxysmal atrial fibrillation, which has not been demonstrated, this test can help to detect episodes of arrhythmia, as can other cardiac monitoring methods.
The diagnosis should be completed with studies to rule out the above-mentioned causes of atrial fibrillation.
Atrial fibrillation: treatment
The cardiology specialist decides on the treatment depending on whether the cause is known and whether it is treatable. Leaving aside the treatment of the cause, if known, the objectives of treatment should be aimed at:
- Prevent the formation of clots or thrombi in the cardiac cavities.
- Restoring normal heart rate, when possible.
- Controlling heart rate
- Prevent or treat heart failure.
For the prevention of clot formation, oral anticoagulants are usually used, which require periodic controls to safely set the necessary dose. Currently there are also other anticoagulants with a better safety profile that do not require periodic coagulation controls. The physician will establish the need for this type of treatment on the basis of its benefit versus the risk that it may cause serious bleeding.
A second aspect is to assess the recovery of normal heart rhythm. This can be achieved either by drugs or by electrical cardioversion. The latter treatment consists of provoking an electric shock in the precordial region; it is a simple outpatient procedure performed under intravenous anesthesia.
When atrial fibrillation has been successfully suppressed and normal heart rhythm restored, antiarrhythmic drugs are usually prescribed to prevent relapse. Anticoagulation therapy is also continued for as long as it is deemed appropriate depending on the characteristics of each patient.
When it is not possible to recover the heart’s normal sinus rhythm or there is a recurrence of atrial fibrillation, the specialist will opt for a therapeutic strategy aimed at controlling the heart rate.
Finally, it is important to mention invasive methods such as ablation, which consists of eliminating the sites where atrial fibrillation originates by introducing catheters inside the heart, which send radiofrequency waves capable of destroying the tissue where the abnormal electrical signals that trigger it originate.