What is Atrial Fibrillation?

Atrial fibrillation, or AFib, is a type of arrhythmia that is characterized by a rapid heart rate above the normal range of 60 to 100 beats per minute. Unlike tachycardia, which is somewhat similar in that it also manifests itself in fast heartbeat, AFib is accompanied by irregular contractions of the heart.

Mechanics of atrial fibrillation

AFib happens when the properly-timed impulses sent by the heart’s natural pacemaker (sinoatrial node) and passed along by atrioventricular node are sabotaged by chaotic impulses that go off in the left upper chamber of the heart where they do not normally occur.

Underlying causes of atrial fibrillation

The disruption in the heart’s electrical system that leads to AFib is caused by the damage to the heart’s structure. Thus, the underlying causes of AFib are anything that has a detrimental effect on heart muscles or heart tissue.

Among the most common medical triggers are the following:

  • high blood pressure
  • coronary artery disease
  • heart attack
  • heart surgery
  • congenital heart conditions (the ones you were born with)

It goes without saying that the causes enumerated above most commonly have lifestyle and demographic factors in their roots, the most prominent being smoking, alcohol consumption, obesity and old age.


Photo by Simon Migaj on Unsplash

Akin to all other types of arrhythmia that ultimately cause improper blood flow and oxygen saturation, AFib is characterised by a set of symptoms that are similar to those of tachycardia and bradycardia, namely:

  • palpitation (a fluttering sensation in your chest, irregular heartbeat)
  • weakness
  • dizziness
  • shortness of breath
  • chest pain
  • inability to exercise
  • lightheadedness

What makes atrial fibrillation so important to be aware of is the gravity of the consequences it may have. According to the American Heart Association AFib increases your risk of stroke fivefold.

How does atrial fibrillation cause stroke?

In order to understand what exactly causes stroke we will need to go back to the mechanics of AFib. As we already know, during an onset of AFib the heart beats rapidly and irregularly. What happens as a result of this is that blood is not properly pumped out of the heart. This may lead to pooling of the blood in the upper chambers of the heart and its clotting as a result of this. Should a clot of this kind dislodge, it will most likely travel to the brain, creating a blockage and interrupting blood supply to the brain. This will, in turn, lead to lack of oxygen and nutrients and subsequent dying of brain cells, which is exactly what causes a stroke.

Reducing the risk

Smoking. According to a study of causes of AFib conducted over 13 years, current smokers have a twofold increase in the risk of developing atrial fibrillation as opposed to those who have never smoked. For former smokers the risk is lower with a ratio of 1.3.

Alcohol. Studies have shown that if we take one drink a day as maximum “healthy” dosage for an adult, every extra drink increases the likelihood of AFib by 8%. Thus, it is fairly easy to imagine how much of a risk one runs in case of heavy drinking or binge drinking.

Obesity. An estimated 30% of the world’s population suffers from this condition and it is connected with a 40% increase in the risk of having AFib. At the same time, losing even 10% of excess body weight is associated with a 50% chance of achieving freedom from AFib without any additional medications.

As with any heart condition, prevention seems to be the best policy and AFib is no exception, meaning that heart monitoring and appropriate lifestyle changes can rid you of these worries altogether.

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