What causes AF?

The exact causes of AF remain unclear.  In 30% of patient, no cause can be identified.  In the remaining patients; many risk factors have been shown to contribute to the development of AF. 

The most common underlying causes of AF are high blood pressure, thyroid disease and, to a lesser extent, coronary artery disease and diabetes. Diet, lifestyle and other factors that contribute to the risk of AF include physical and emotional stress and excessive caffeine, alcohol or illicit drug intake. 

Cardiothoracic surgery can also lead to AF, commonly affecting between 20-50% of patients.  Less intuitively; elite athletes are also prone to suffering from AF.  Why this might be is explored below.
 


 

Risk factors for AF:

  • High blood pressure
  • Thyroid disease
  • Heart valve disease (a special case discussed later)
  • Coronary artery disease
  • Diabetes
  • Emotional and physical stress
  • Caffeine
  • Alcohol
  • Recreational drugs
     

Substrate and tissue factors

Much of the current research into treatments for AF also explores the likelihood that there are two main causative factors for AF:

  1. Substrate factors: those that affect the tissue of the atrial wall, creating an environment where chaotic electrical activity can occur
  2. Trigger factors: those that result in the creation of chaotic electrical activity


There are several well-understood abnormalities of the heart that lead to the enlargement of the atria, and the slow transmission of electrical impulses in the atrial walls.  Both of these could create an environment (or substrate) in which chaotic impulses are not subdued by the heart’s natural pacemaker.

Conversely, high blood pressure might be a trigger.  It is known that the pulmonary veins are the usual source of the rogue electrical impulses that result in AF.  It has been suggested that high blood pressure might distort the tissue of the pulmonary veins, leading to damage, which results in the generation of chaotic impulses. Similarly, valvular disease or the stresses of high-intensity and endurance exercise might result in AF triggers.

Causes of different types of AF

Further exploration of this theory has provided a possible explanation for the different types of AF.  A patient with triggers for AF, but relatively healthy atrial heart tissue, might experience intermittent (paroxysmal) AF. This is where bursts of chaotic electrical activity are ultimately brought under control in the atrial wall.  Whereas, a patient with both triggers and unhealthy atrial substrate would endure AF that was never controlled within the tissue of the atrial walls, leading to persistent AF.

The progression of AF

It is also understood that AF commonly begins with occasional (paroxysmal) AF that then develops into longer and more frequent episodes until it eventually becomes persistent.  This is believed to result from the effect that AF itself has on the tissue of the atrial walls, causing them to stretch and dilate; creating a substrate for persistent AF. 

The trigger/substrate model for AF has proved extremely useful in research and highlights the importance of early treatment to halt the progression of AF, particularly in symptomatic patients.

Add Calendar?: 

Causes of Atrial Fibrillation

What causes AF?

The exact causes of AF remain unclear.  In 30% of patient, no cause can be identified.  In the remaining patients; many risk factors have been shown to contribute to the development of AF. 

The most common underlying causes of AF are high blood pressure, thyroid disease and, to a lesser extent, coronary artery disease and diabetes. Diet, lifestyle and other factors that contribute to the risk of AF include physical and emotional stress and excessive caffeine, alcohol or illicit drug intake. 

Cardiothoracic surgery can also lead to AF, commonly affecting between 20-50% of patients.  Less intuitively; elite athletes are also prone to suffering from AF.  Why this might be is explored below.
 


 

Risk factors for AF:

  • High blood pressure
  • Thyroid disease
  • Heart valve disease (a special case discussed later)
  • Coronary artery disease
  • Diabetes
  • Emotional and physical stress
  • Caffeine
  • Alcohol
  • Recreational drugs
     

Substrate and tissue factors

Much of the current research into treatments for AF also explores the likelihood that there are two main causative factors for AF:

  1. Substrate factors: those that affect the tissue of the atrial wall, creating an environment where chaotic electrical activity can occur
  2. Trigger factors: those that result in the creation of chaotic electrical activity


There are several well-understood abnormalities of the heart that lead to the enlargement of the atria, and the slow transmission of electrical impulses in the atrial walls.  Both of these could create an environment (or substrate) in which chaotic impulses are not subdued by the heart’s natural pacemaker.

Conversely, high blood pressure might be a trigger.  It is known that the pulmonary veins are the usual source of the rogue electrical impulses that result in AF.  It has been suggested that high blood pressure might distort the tissue of the pulmonary veins, leading to damage, which results in the generation of chaotic impulses. Similarly, valvular disease or the stresses of high-intensity and endurance exercise might result in AF triggers.

Causes of different types of AF

Further exploration of this theory has provided a possible explanation for the different types of AF.  A patient with triggers for AF, but relatively healthy atrial heart tissue, might experience intermittent (paroxysmal) AF. This is where bursts of chaotic electrical activity are ultimately brought under control in the atrial wall.  Whereas, a patient with both triggers and unhealthy atrial substrate would endure AF that was never controlled within the tissue of the atrial walls, leading to persistent AF.

The progression of AF

It is also understood that AF commonly begins with occasional (paroxysmal) AF that then develops into longer and more frequent episodes until it eventually becomes persistent.  This is believed to result from the effect that AF itself has on the tissue of the atrial walls, causing them to stretch and dilate; creating a substrate for persistent AF. 

The trigger/substrate model for AF has proved extremely useful in research and highlights the importance of early treatment to halt the progression of AF, particularly in symptomatic patients.

You are now leaving The Heart of AF website

Please Note: While we can recommend sites to you, we CANNOT be held responsible for information that you may collect from these sites.

OK, proceed Return to site