Morphology and pathophysiology of target anatomical sites for ablation procedures in patients with atrial fibrillation. Part I: atrial structures (atrial myocardium and coronary sinus).

Experimental and clinical evidence suggests that the natural history of atrial fibrillation is characterised by increased structural remodelling, which may play a pivotal role in maintaining the arrhythmia and clinically favours progression from paroxysmal to persistent atrial fibrillation. In this setting, anti-arrhythmic therapy gradually becomes inefficient, and this limitation has led to the introduction of new non-pharmacological interventions such as surgical or catheter ablation. At the same time, interest in the functional morphology and electrophysiological properties of the atria and their related anatomical structures has greatly increased. This article is the first of a two-part review whose main purpose is to describe the anatomical and functional details of some of the principal anatomical locations that are commonly targeted by ablative procedures to treat this supraventricular arrhythmia. In particular, this manuscript has dealt with the atrial structures (atrial myocardium and coronary sinus). General information on ablation procedures has also been provided.