AF occurs when the SA is overwelmed by disorganized electrical impulses from the atria and pulmonary veins. One of the main factors that causes AF is the dialtion of the heart atrium. This is because, once dilation occurs, several enzymes and hormones are secreted to remodel the myo cardium in such a way that it is able to withstand the pressure. This happens over time. As the remodelling occurs, the heart muscle losses its elasticity and its efficiency. In order to overcome this, the heart forces more blood into its compartments to make up for its loss and once again, the atrium to dilate and the whole process happens all over again.

From here, there are two different ways in which AF could happen. The first one is when the heart undergoes fibrosis again and again until the SA node undergoes fibrosis as well. Or the electical conduction of the heart could be disrupted by muscle allignment due to fibrosis (myocaridal dissaray) which causes AF.


Table 1. Etiologies of Atrial Fibrillation

1. Atrial pressure elevation (leading to dilatation)
Valvular disease: mitral/tricuspid regurgitation or stenosis, mitral valve prolapse
Hypertrophic cardiomyopathy (HCM)
Pulmonary hypertension (COPD with cor pulmonale)
Pulmonary embolism
Intracardiac thrombi or tumor

2. Inflammatory and infiltrative process
Pericarditis/myocarditis
Age induced atrial fibrosis

3. Infectious process
Any infections and fever

4. Endocrine disorders
Hyperthroidism

5. Atrial ischemia
Myocardial infarction

6. Drugs
Alcohol (holiday heart)
Caffeine

7. Idiopathic
Lone afib if less than 60 years old

8. Familial


Risk Factors.

basically, the things that predisposes you to have Atrial Fibrillation are diseases or conditions that eventually leads to the fibrosis of the heart tissues, increased intra-cardial pressure, hypertension, especially in the pulmonary vessels, etc.

here are some of the risk factors which increases your chances of having AF

• coronary heart disease
• heart failure
• Rheumatic heart disease
• Structural heart defects, such as mitral valve disorders
• pericarditis (a condition in which the membrane, or sac, around your heart is inflamed)
• congenital heart defects
• Sick sinus syndrome (a condition in which the heart's electrical signals don't fire properly and the heart rate slows down; sometimes the heart will switch back and forth between a slow rate and a fast rate)