Atrial electrophysiologic remodeling: another vicious circle?

INTRODUCTION: With few exceptions, acquired heart disease is the result of gradual changes in the heart, progressing during several months or years. This also includes certain cardiac arrhythmias, as for instance atrial fibrillation (AF). In spite of the important role of slowly progressing pathologic processes, most of our knowledge about mechanisms of cardiac arrhythmias is based on acute experiments. Only recently, the attention also is more focused on long-term adaptation processes like cardiac memory, electrical remodeling, and tachycardia-induced cardiomyopathy. In experimental animal models, it has been shown that AF induces a vicious circle of electrophysiologic and structural changes that inevitably leads to "domestication" of the arrhythmia ("AF begets AF"). In this article, the studies on AF-induced electrophysiologic and cellular remodeling are discussed.