Mapping atrial fibrillation (original) (raw)

Pathogenesis of AF: impact on intracardiac signals

2011

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and is responsible for the highest number of rhythm-related disorders and cardioembolic strokes worldwide. Intracardiac signal analysis during the onset of paroxysmal AF led to the discovery of pulmonary vein as a triggering source of AF, which has led to the development of pulmonary vein ablation-an established curative therapy for drug-resistant AF. Complex, multicomponent and rapid electrical activity widely involving the atrial substrate characterizes persistent/permanent AF. Widespread nature of the problem and complexity of signals in persistent AF reduce the success rate of ablation therapy. Although signal processing applied to extraction of relevant features from these complex electrograms has helped to improve the efficacy of ablation therapy in persistent/permanent AF, improved understanding of complex signals should help to identify sources of AF and further increase the success rate of ablation therapy.

Atrial Fibrillation Pathophysiology

Circulation, 2011

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is an important contributor to population morbidity and mortality. An arrhythmia that is particularly common in the elderly, AF is growing in prevalence with the aging of the population. Our understanding of the basic mechanisms that govern AF occurrence and persistence has been increasing rapidly. This article reviews the basic pathophysiology of AF over a broad range of levels, touching on the tissue mechanisms that maintain the arrhythmia, the relationship between clinical presentation and basic mechanisms, ion channel and transporter abnormalities that lead to ectopic impulse formation, basic models and tissue determinants of reentry, ion channel determinants of reentry, the nature and roles of electric and structural remodeling, autonomic neural components, anatomic factors, interactions between atrial and ventricular functional consequences of AF, and the basic determinants of atrial thromboembolism. We th...

Atrial remodeling: evolving concepts

Indian pacing and electrophysiology journal, 2003

The term "Electrophysiological remodeling" defines the changes of atrial electrophysiologic properties taking place in atrial myocites during atrial fibrillation and/or following periods of sustained atrial fibrillation (AF). Early research was prompted by clinical observations: many patients were seen to get through increasingly frequent and longer paroxisms of AF to persistent AF, until chronic AF eventually ensued, without significant changes of underlying heart disease. Indeed, clinical electrophysiology investigations reported peculiar differences between AF patients and patients without atrial arrhythmias. It was felt that the electrophysiologic milieu was the cause of AF 1,2 , until a change of perspective occurred in the early 90's, thanks to experimental research. In his pioneering work, Wijffels kept goats fibrillating by an implanted device, while measuring atrial refractoriness and its rate adaptation as spontaneous restoration of sinus rhythm occurred. He found that, after several self terminating short bouts of AF, the arrhythmia became considerably longer until a duration of days or weeks was reached. The electrophysiologic companionship of AF pattern transformation consisted of significant shortening of atrial fibrillation cycle, which was paralleled by shortening of atrial ERP and loss of ERP adaptation to heart rate: either flat (no change with shortening cycle length) or inverted (paradoxical shorter ERP at longer cycle length) ERP relationships to cycle length were observed. This findings had been already observed in AF patients 1,2 ; the novelty was that AF itself was the cause of these abnormal electrophysiologic properties, which could in turn promote further recurrences of AF, and arrhythmia persistence in some cases. By the light of this observations, AF may be seen as self-maintaining by creating a functional electrophysiologic substratum, despite the coexistence of only minor structural heart disease or occasional triggers. This principle has been summarised by Maurits Allessie in the aphorism "AF begets AF". Following this observations, several studies have addressed the issue of the mechanisms by which atrial electrophysiologic remodeling occurs in different settings: basic electrophysiology, experimental electrophysiology, and clinical electrophysiology. It is nowadays believed that, beyond structural heart disease, changes of the atrial electrophysiologic substratum are responsible for AF recurrence and/or perpetuation.