Inter-relationships of atrial fibrillation and atrial flutter mechanisms and clinical implications.
There is a close interrelationship between atrial fibrillation (AF) and atrial flutter (AFL). Atrial fibrillation of variable duration precedes the onset of AFL in almost all instances; during AF, the functional components needed to complete the AFL re-entrant circuit, principally a line of block (LoB) between the vena cavae, are formed; if this LoB does not form, classical AFL does not develop. In contrast, there seems to be a spectrum of atrial re-entrant circuits (drivers) of short cycle lengths (CLs) (i.e., AFL). When the CL of the AFL re-entrant circuit is so short that it will only activate portions of the atria in a 1:1 manner, the rest of the atria will be activated rapidly but irregularly (i.e., via fibrillatory conduction), resulting in AF. In short, there are probably several mechanisms of AF, 1 of which is due to a very rapid AFL causing fibrillatory conduction. All of these interactions of AF and AFL have important clinical implications.
Waldo
Albert L
AL
Department of Medicine, Division of Cardiovascular Medicine, Case Western Reserve University/University Hospitals of Cleveland Case Medical Center, Cleveland, Ohio 44106-5038, USA. albert.waldo@case.edu
Feld
Gregory K
GK
D000818:Animals; D001281:Atrial Fibrillation / Q000150:complications* / Q000503:physiopathology*; D001282:Atrial Flutter / Q000150:complications* / Q000503:physiopathology*; D006801:Humans