Left Atrial Myocardial Extension onto Pulmonary Veins in Humans:

Abstract

The observation that the peripheral zones of myocardial sleeves are associated with increasing connective tissue deposition between myocardial muscle groups suggests a degenerative change that, from the histologic viewpoint, fits with progressive ischemia. These changes could provide a basis for microreentry and, hence, for atrial arrhythmias.