Mechanisms of atrial fibrillation.
Mechanisms of Atrial Fibrillation. Based on experimental studies in the canine heart and an early computer model, atrial fibrillation (AF) has been thought to be due to multiple reentrant wavelets. However, subsequent studies in animal models are most consistent with a mechanism of AF due to a stable reentrant circuit of short cycle length or unstable reentrant circuits of short cycle length that drive the atria so fast that much or most of the atrial tissue manifests fibrillatory conduction. Limited mapping studies in patients during open heart surgery and during electrophysiologic studies using endocardial catheter electrodes also are most consistent with the concept of a driver, seemingly most often a focus in or near one or more of the pulmonary veins, precipitating and maintaining AF. However, a precise understanding of the mechanism(s) of AF in patients is not yet available.
Department of Medicine, Division of Cardiology, Case Western Reserve University School of Medicine, and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA. alw2@po.cwru.edu
Albert L
AL
Waldo
D000200:Action Potentials; D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D001683:Biological Clocks; D018780:Body Surface Potential Mapping / Q000379:methods*; D004558:Electric Stimulation; D006325:Heart Atria / Q000294:innervation* / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D009431:Neural Conduction