Pulmonary veins-left atrial junction: anatomic and histological study.

Pulmonary veins (PVs) are the target of ablation procedures to cure paroxysmal atrial fibrillation (PAF). There are few anatomic and histological studies of PVs. Sixteen human hearts were obtained from autopsies performed at our hospital and cadavers from a local medical school. The anatomic relationship 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 longitudinally, 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 myocardial sleeve extended from the LA onto the adventitial surface of the PV. The sleeve was distinct from the smooth muscle in the PV media, from which it was separated by loose fibrous strands. There was no microscopical boundary between the PV and the LA endocardium. The PV join the LA at variable angles. Each PV is surrounded by a myocardial sleeve extending from the LA.

Histopathology of the internal anal sphincter in chronic anal fissure.

A prospective study of 18 consecutive patients undergoing unilateral, partial-thickness, distal, internal sphincterotomy for the treatment of chronic anal fissure was performed. Biopsies were taken from the base of the fissure and from the lateral muscle before division. Normal specimens were taken from the internal anal sphincter of patients undergoing abdominoperineal resection. Specimens confirmed the presence of fibrosis throughout the internal anal sphincter in patients with anal fissures, but none in controls.