title: Triggers and anatomical substrates in the genesis and perpetuation of atrial fibrillation.
abstract: The definition of atrial fibrillation (AF) as a functional electrical disorder does not reflect the significant underlying structural abnormalities. Atrial and Pulmonary Vein (PV) muscle sleeve microstructural remodeling is present, and establishes a vulnerable substrate for AF maintenance. In spite of an incomplete understanding of the anatomo-functional basis for AF, current evidence demonstrates that this arrhythmia usually requires a trigger for initiation and a vulnerable electrophysiological and/or anatomical substrate for maintenance. It is still unclear whether the trigger mechanisms include focal enhanced automaticity, triggered activity and/or micro re-entry from myocardial tissue. Initiation of AF can be favored by both parasympathetic and sympathetic stimulation, which also seem to play a role in maintaining AF. Finally, evolving clinical evidence demonstrates that inflammation is associated with new-onset and recurrent AF through a mechanism that possibly involves cellular degeneration, apoptosis, and subsequent atrial fibrosis.
authors.affiliation: Departamento de Anatomía y Biología Celular, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain. dasaqui55@yahoo.com
authors.forename: Damián
authors.initials: D
authors.lastname: Sánchez-Quintana
authors.forename: José Ramón
authors.initials: JR
authors.lastname: López-Mínguez
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Pizarro
authors.forename: Margarita
authors.initials: M
authors.lastname: Murillo
authors.forename: José Angel
authors.initials: JA
authors.lastname: Cabrera
mesh_terms: D001281:Atrial Fibrillation / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D054326:Coronary Sinus / Q000473:pathology; D005355:Fibrosis / Q000209:etiology / Q000473:pathology; D006325:Heart Atria / Q000473:pathology; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D018810:Magnetic Resonance Angiography; D009205:Myocarditis / Q000209:etiology / Q000473:pathology; D009206:Myocardium / Q000473:pathology*; D011667:Pulmonary Veins / Q000473:pathology; D012849:Sinoatrial Node / Q000502:physiology; D014683:Vena Cava, Superior / Q000473:pathology
chemical_list: D007473:Ion Channels