Pulmonary veins-left atrial junction: Anatomic and histological study

Pulmonary veins (PVs) are the target of ablation procedures to cure paroxys mal atrial fibrillation (PAF). There are few anatomic and histological stud ies of PVs. Sixteen human hearts were obtained from autopsies performed at our hospital and cadavers from a local medical school. The anatomic relatio nship between the PVs and the left atrium (LA) was categorized according to the spatial orientation of the veins within horizontal and vertical planes viewed from the dorsal aspect of the LA. The PVs were sectioned longitudin ally, and the sections were stained with hematoxylin and eosin. In addition , selected sections were stained with antismooth muscle antibodies (vessel wall), antipankeratin, and antimyoglobin antibodies (myocardium). The PV-LA junction has variable orientations. Confluent superior and inferior veins, observed in 25% of the hearts, were more common on the left side. A myocar dial sleeve extended from the LA onto the adventitial surface of the PV. Th e sleeve was distinct from the smooth muscle in the PV media, from which it was separated by loose fibrous strands. There was no microscopical boundar y between the PV and the LA endocardium. The PV join the LA at variable ang les. Each PV is surrounded by a myocardial sleeve extending from the LA.