Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained type of cardiac arrhythmia, characterised by irregularly irregular ventricular pulse and loss of association between the cardiac apex beat and radial pulsation.

Evidence suggests an increasing prevalence and incidence worldwide, currently affecting 0.5% of the world’s population.The risk of AF increases with age, particularly after age 60,affecting roughly one in every 10 people 80 years and older according to the CDC.

AF may be either occasional, persistent or permanent. With occasional AF, symptoms come and go; this type of AF is called paroxysmal AF. As a first step in diagnosis, an electrocardiogram (ECG) should be performedin all patients with suspected AF following an irregular pulse. An ECG is diagnostic except in paroxysmal AF between attacks.

The evaluation of AF involves uncovering the cause of the arrhythmia. Diagnostic investigation typically includes a complete history, physical examination, ECG, transthoracic echocardiogram, complete blood count, and serum thyroid stimulating hormone level. Some may also benefit from an in-depth evaluation that may include correlation of the heart rate response to exercise, exercise stress testing, chest X-ray, transesophageal echocardiography, and other studies.

In people with suspected paroxysmal AF undetected by standard ECG recording, a 24-hour ambulatory ECG monitor can be used for those with suspected asymptomatic episodes or symptomatic episodes less than 24 hours apart and an event recorder ECG for those with symptomatic episodes more than 24 hours apart.

Whilst AF can feel unusual and frightening for some patients, others experience no symptoms. Either way, it doesn’t usually have harmful consequences. The real danger is the increased risk of strokeand related heart problems. Symptoms can range from palpitations, weakness, fatigue, reduced ability to exercise, lightheadedness, dizziness, confusion, shortness of breath and chest pain.

Sometimes the cause of AF is unknown. In other instances, the cause is damage to the heart's electrical system from conditions such as longstanding, uncontrolled high blood pressure or artery disease, chronic lung disease, cardiomyopathy orcongential heart disease. AF is also the most common complication after heart surgery.

Less common causes of AF include hyperthyroidism, pericarditis and viral infection. In at least 10% of people with AF, no underlying heart disease is found although in many of these cases, AF may be related to alcohol or excessive caffeine, stress, certain drugs, electrolyte or metabolic imbalances, or severe infections. In some people, no cause can be found.

Management of AF involves control of the arrhythmia (by rhythm or rate control) and thromboprophylaxis to prevent strokes.

Any underlying cause such as acute infection or,hyperthyroidism needs to be treated as well as any associated heart failure.

Options available to treat AF includelifestyle changes, medication, certain medical procedures and surgery. The choice of treatment is based on heart rate and symptoms. Rate control is the first-line strategy. When medications do not work or are not tolerated, a procedure may be necessary, such as electrical cardioversion, pulmonary vein isolation ablation, catheter ablation of the AV node with a pacemaker, or device therapy.