Atrial Fibrillation: A
continuous and chaotic arrhythmia of the left and right atria. Paroxysmal
(intermittent) atrial fibrillation is usually associated with normal hearts;
chronic atrial fibrillation is associated with heart disease. Approximately 80%
of atrial fibrillation originates in the left atrium of the heart. Symptoms of
atrial fibrillation include dizziness and weakness.