Atrial fibrillation is associated with many heart conditions -- underlying heart valve disease, longstanding hypertension, coronary artery disease, pericarditis, cardiac surgery, heart failure, and virtually all other varieties of heart disorders.
There are also non-cardiac conditions that can lead to atrial fibrillation. Hyperthyroidism (high thyroid levels) is commonly accompanied by atrial fibrillation. On occasion, hypothyroidism (low thyroid levels) can also be accompanied by atrial fibrillation.
Atrial fibrillation also can accompany acute pulmonary (lung) conditions like pulmonary embolus (blood clot in the lung) or pneumonia. Ingestion of caffeine, amphetamines or other stimulants (such as cold remedies containing pseudoephedrine) can cause atrial fibrillation in some people, as well as after drinking as few as two or three alcoholic beverages -- a condition known as " Holiday Heart."
When an underlying cause can be identified for atrial fibrillation, then treating that underlying cause will often eliminate the arrhythmia.
Often, There Is No Clear Reason for AF
In many - probably most - patients, no particular underlying cause for atrial fibrillation can be identified, in which case the atrial fibrillation is said to be "idiopathic." ("Idiopathic" is medical science's way of saying, "we don't know what the heck is causing it.")The odds of getting idiopathic atrial fibrillation are related to one's age. With each successive decade of life, the risk increases, so that while atrial fibrillation is rare in patients under 50, it becomes quite common among people in their 80s and 90s.
When idiopathic atrial fibrillation is seen in younger patients (those below the age of 50), the term "lone atrial fibrillation" is frequently used. This term reflects the fact that no identifiable cause for the arrhythmia is present, so it is the "lone" abnormality present. Most patients with lone atrial fibrillation are usually in a normal heart rhythm, but have episodes of the arrhythmia that are of varying frequency and duration (that is, they have "paroxysmal" atrial fibrillation).
Sources:
Constantini, O. and Stambler, B. Approach to the Patient with Atrial Fibrillation. In: Management of Cardiac Arrhythmias, Ganz LI and Braunwald E. Eds. Humana Press, Totowa, NJ.; 2002.
