Catheter ablation for atrial fibrillation.

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation with associated deterioration of atrial mechanical function.1 It is the most common cardiac arrhythmia, becomes more prevalent with age,2 and is associated with an increased long-term risk of stroke, heart failure, and all-cause mortality.3 AF can occur in the absence of underlying heart disease but is more frequent in connection with mitral valve disease, heart failure, ischemic heart disease, and hypertension.4 The most frequent pathological observations in AF are atrial fibrosis and loss of atrial muscle mass.5,6 Although the severity of fibrosis reflects the duration of preexisting AF,7 fibrosis can also occur in association with inflammation in the absence of other cardiac pathology6 and may contribute to the onset of AF.8 Molecular, ionic, and genetic influences have all been implicated in AF and are reviewed in detail elsewhere.9 It is likely that most AF occurs primarily in the context of an interplay between left atrial (LA) electrical and mechanical dysfunction and later becomes self-perpetuating by promoting further electromechanical change during ongoing fibrillation.10