Possible causes of atrial fibrillation

The most common cause of atrial fibrillation is defiantly abnormality in the heart's structure. Many diseases that could affect the heart's valves or pumping system such as long-term high blood pressure are also likely causes . However, some people who have atrial fibrillation don't have any underlying heart disease, and the cause is unknown.

Other possible causes of atrial fibrillation include:

• High blood pressure
• Abnormal heart valves
• Congenital heart defects
• An overactive thyroid or other metabolic imbalance
• Exposure to heart stimulants, such as caffeine or tobacco, or to alcohol
• Sick sinus syndrome — this occurs when the heart's natural pacemaker stops functioning properly
• Emphysema or other lung diseases
• Heart surgery
• Coronary artery disease
• Hypertrophic cardiomyopathy
• Previous heart surgery
• Viral infections
• Stress due to pneumonia, surgery or other illnesses

Classification of atrial fibrillations

The American Heart Association have proposed the following classification system based on simplicity and clinical relevance:

First Detected
Any patient newly diagnosed with atrial fibrillation fits in this category, as the exact onset and chronicity of the disease is often uncertain.

Recurrent
Any patient with 2 or more identified episodes of atrial fibrillation is said to have recurrent atrial fibrillation. This is further classified into paroxysmal and persistent based on when the episode terminates without therapy.

Paroxysmal
Atrial fibrillation is said to be paroxysmal when it terminates spontaneously within 7 days, most commonly within 24 hours.

Persistent
Persistent or chronic atrial fibrillation is atrial fibrillation established for more than seven days. Differentiation of paroxysmal from chronic or established atrial fibrillation is based on the history of recurrent episodes and the duration of the current episode of the condition.

Lone atrial fibrillation
Lone atrial fibrillation is defined as atrial fibrillation in the absence of clinical findings. Patients with this condition who are under 65 have the best prognosis.

Risk factors

There are several risk factors that could be linked to atrial fibrillation and the most common are:

Age
The older you are, the greater your risk of atrial fibrillation. As you age, the electrical and structural properties of the atria can change. This may lead to the breakdown of the normal atrial rhythm.

Other heart diseases
Anyone with heart disease faces an increased risk of atrial fibrillation.

Other conditions
It is proven that people with thyroid problems, diabetes and high blood pressure have an elevated risk of atrial fibrillation.

Obesity
It is considered that obesity also may play an important role in the development of atrial fibrillation.

Diagnosis of atrial fibrillation

Electrocardiogram

Atrial fibrillation is best diagnosed with an electrocardiogram, an investigation performed routinely whenever irregular heart beat is suspected. Characteristic findings are:

• absence of P waves
• unorganized electrical activity in their place
• irregularity of R-R interval due to irregular conduction of impulses to the ventricles

Holter monitor testing

This is a portable version of an ECG which is being used to monitor patient’s heart activity for 24h. It's especially useful in diagnosing rhythm disturbances that occur at unpredictable times. Patient wears the monitor under clothing.

Echocardiogram

This is a very good and effective diagnostic tool. In this test, the sound waves are used to produce a video of patient’s heart. Sound waves are directed at heart from a wand-like device called transducer that's held on the patient’s chest. The sound waves that bounce off the patient’s heart are reflected back through the chest wall and processed electronically to provide video images of heart in motion.

Blood tests

These blood tests can help a doctor rule out thyroid problems or blood chemistry abnormalities that may lead to atrial fibrillation.
Possible complications of atrial fibrillation

There are two possible and very dangerous complications of atrial fibrillation. These are:

Stroke
The fact is that the chaotic rhythm may cause blood to pool in your atria and form clots. These blood clots could dislodge from the heart and travel to the brain. There they might block the blood flow, causing a stroke.  A blood clot can also lodge in other blood vessels, such as those supplying the kidneys or legs.  

Congestive heart failure
Atrial fibrillation alone may weaken the heart, leading to heart failure.
This is a condition in which a patient’s heart can't circulate enough blood to meet the body's needs.