ATRIAL FIBRILLATION (AF)
Chaotic, rapid heartbeats
AF is an arrhythmia characterized by chaotic cardiac beats that are irregularly irregular. The heartbeat frequency can even be beyond 150 beats per minute....
Well-organized electrical system
In order for all cardiac structures to contract normally, the heart is provided with a well-organized electrical system under the direction of a conductor
It is an arrhythmia located in the atria
Atrial fibrillation is located in the atria (higher cavities of the heart). It prevents them from contracting effectively.
The atria behave like musicians playing different songs simultaneously, without their bandmaster. It’s an electrical cacophony.
When one looks at the atria while in atrial fibrillation, it is much like seeing "jello" being shaken. There is a lot of erratic movement, but no effective contraction.
The gatekeeper is under fire
The ventricles do not contract at regular intervals either.
As there is no more “maestro” to manage the electric activity of the atria, the atrioventricular node (the gatekeeper of the electric impulse towards the ventricles) gets bombarded by the chaotic electric impulses from the atria. The transmission of the electric signal towards the ventricles will also be irregularly irregular.
The pulse does not have tempo anymore.
Risk of clot formation in the heart
The main risk of AF is systemic embolism.
As the atria do not contract in an effective way, a blood clot may form on the walls of the atria because blood does not circulate; it stagnates. Portions of this clot may detach and reach the general circulation, which can lead to arterial embolisms.
If a clot reaches the brain, it is then a CVA (stroke).
In spite of that, AF is considered a benign arrhythmia.
One can live very well with AF. There can be no symptoms or perception of palpitations
Some patients can be completely asymptomatic, as no palpitations are perceived. For others, palpitations can be fast, uncomfortable and a source of anxiety.
In certain situations, the frequency may be normal or even slow, because of medication or of a disease of the electrical system of the heart.
6% of the general population is affected and often without identifiable causes
The causes of AF are multiple, but often there is no identifiable cause. The incidence of AF, i.e. the frequency of this condition in the general population is 6%.
On the other hand, it is well known that older patients, patients with high blood pressure or diabetes develop AF more often.
Certain diseases or problems can contribute to the occurrence of AF, such as vascular diseases, problems of the cardiac muscle or the coronary arteries, inflammation of the pericardium after cardiac or chest surgery, pulmonary problems (COPD, pulmonary embolism) and even certain thyroid problems (hyperthyroidism).
Two approaches to treatment
How is AF treated? It can be done in two ways, so to speak, by either controlling the heart rate (slowing it down) or by controlling the heart rhythm (stopping the arrhythmia) and bringing it back to its normal so-called sinus rhythm.
Several studies compared those two ways, but it appears that the two methods are equivalent and that there is no significant advantage of one over the other.
Controlling the heart rate
If there is no symptom of arrhythmia, it is simpler to control the heart rate. The cardiologist would normally choose this option initially.
It is possible, however, that while trying to slow down the frequency, the latter becomes too slow. The cardiologist will then discuss with you about the need of inserting a permanent pacemaker to ensure an adequate heart rate if the medication slows down the heart rate too much.
The pacemaker provides an electrical backup to make sure that the heart rate does not go below a predetermined threshold
Stopping the arrhythmia: medications or specialized invasive procedures
If controlling the heart rate by medication fails, if there are significant side effects, or if AF is interfering with the patient’s lifestyle, the doctor may consider another option. This option is to regularize the heart rate by an electric shock. It is called electrical cardioversion.
Electrical cardioversion or electric shock
The electrical cardioversion is a method to restore a regular heart rhythm by the administration of an electrical shock through the chest. This is different and not as dramatic as what you might have seen on TV shows, where the patient’s body literally jumps with the shock… This method requires a short period of anesthesia. Once the patient is fully sedated, the electrical shock is applied. The sedation then wears off and the patient wakes up.
This procedure, like any other procedure, involves some risks. When the doctor chooses this option, the risks and benefits are explained to the patient.
When the usual oral treatment with side effects fail, a more invasive procedure called ablation can be considered. This procedure allows the identification of the AF's points of origin at the pulmonary veins level, and those are then burned using electrical waves (radiofrequency) or a cryotherapy device (that creates frostbites). The procedure will be explained in detail later on.
Chronic or by episodes
Atrial fibrillation can be present in a chronic way (permanent) or periodical (paroxysmal atrial fibrillation).
Anticoagulants are not meant to thin the blood, but to prevent blood clots from forming.
To prevent clot formation and embolism
The physician will decide if the use of an anticoagulant medication is indicated, based on certain factors such as age, the presence of diabetes or high blood pressure, a history of stroke or heart failure.
Once this type of medication is initiated, it will most likely be required indefinitely. The physician must weigh the risks of embolization versus the risks of bleeding, whenever he/she decides to prescribe an oral anticoagulant medication.
You should never stop this therapy on your own.