Structural changes of atrial myocardium during chronic atrial fibrillation

Of all known arrhythmia's, atrial fibrillation (AF) is the most often met i n the clinical setting and it is associated with an increase in mortality r isk. Several risk factors for AF have been described and several mechanisms of induction and maintenance have been proposed. Studies in patients with AF have shown that structural changes occur in the atria, but the relations hip between the structural remodelling and the chronicity of the arrhythmia are not well understood. The changes mainly concern adaptive (dedifferenti ation of cardiomyocytes) and maladaptive (degeneration of cells with replac ement fibrosis) features. In order to characterise the time course of the s tructural remodelling the need for animal models which adequately mimic chr onic atrial fibrillation in humans is felt essential. In this review, the s tructural changes that are observed during prolonged sustained AF in patien ts and animal models, are described. Furthermore, the time course and poten tial mechanisms of structural remodelling are discussed and methods for elu cidation of the underlying molecular mechanisms an presented. Cardiovasc Pa thol 2000;9:17-28 (C) 2000 by Elsevier Science Inc.