Histological evaluation of atrial muscle sleeve of pulmonary veins as relevant to trigger mapping and ablation.

BACKGROUND: The atrial myocardial sleeve of the pulmonary vein is the most common source of arrhythmogenic triggers in atrial fibrillation. The present study was designed to study the atrial muscle sleeve in detail, to help in planning and execution of "trigger mapping and ablation" procedure, used for treating resistant atrial fibrillation. METHODS: A longitudinal tissue section was taken along the length of each pulmonary vein including the posterior wall of the left atrium, from 15 normal human formalin fixed hearts. The histological and micro-morphometric details of the atrial muscle sleeve were studied. RESULTS: A muscle sleeve composed of cardiac muscle was found in each pulmonary vein, situated between adventitia and media, and separated from media by clearly defined connective tissue. The fiber arrangement was non uniform and angular changes in the fiber direction were frequent. Autonomic ganglia were found in the adventitia. The sleeve was tapering distally but reduction was not circumferentially uniform, minimum thickness was more for right (~ 0.2 mm) than for left veins (0.1 mm). The mean atrial sleeve length was 6.3 mm; the left veins had longer sleeve then right while left inferior veins had the maximum mean length. CONCLUSION: The trigger mapping should be done for 2 cm on pulmonary veins to fully cover the atrial muscle sleeve. The gradual tapering of the atrial sleeve indicates that the maximum intensity ablative lesions would be needed at the veno-atrial junction while the ablation power should be reduced distally. Distal triggers on right veins would need more ablation then on the left veins.

Translational anatomy of the left atrium and esophagus as relevant to the pulmonary vein antral isolation for atrial fibrillation.

PURPOSE: Pulmonary vein antrum isolation by radiofrequency ablation has become a preferred treatment for atrial fibrillation. The aim of our research is to study the anatomy of the PVantrum and its related structures with special emphasis on the esophageal relation to the various components of the antrum, as thermal injury is a common complication. METHODS: Mediastinal contents were extracted "en bloc" from 30 human formalin fixed adult cadavers to study the posterior wall of the left atrium along with the esophagus. RESULTS: The pulmonary antrum was measured. Each pulmonary ostium was assessed for circumference and muscle thickness. The esophagus was related to the left superior ostium in 90% of cases. The esophagus was traced on the atrial wall in each case; the distance from endocardium was measured at five equidistant lines. AV node distance from the right inferior pulmonary vein was 5 cm. The atrioventricular part of the membranous septum measured 4.2 mm. CONCLUSIONS: For antral isolation the ablation lines are about 3 cm superior, 3.5 cm inferior and about 1 cm apart. The esophagus is ~ 12 mm away at the superior and ~ 7 mm away at the inferior ablation line. On the left ablation line this distance would diminish from 15 to 7 mm. The pulmonary ostial circumference is ~ 5 cm with muscle thickness varying from 0.7 to 4 mm. The left ostia need more ablative power as they have a 60% (1 mm) thicker muscle coat. Care should be taken while ablating round the left superior ostium as the esophagus lies 1-3 cm behind it in 90% of the cases.

Chronic inflammation during osteoarthritis is associated with an increased expression of CD161 during advanced stage.

Increasing evidence suggests a role of inflammation during the pathogenesis of osteoarthritis (OA). The local and systemic inflammation was studied in 33 patients of different KL grades, grade2 (n = 11), grade3 (n = 6) and grade4 (n = 16). The levels of cytokines, adipokines and matrix metalloproteinases (MMPs) were measured in serum and synovial fluid (SF) by flow cytometry and ELISA, respectively. The frequency of T cells and CD161 expression was measured by flow cytometry. The levels of IL-1ß, IL-6 and IL-10 were significantly higher in sera and SF of patients with OA as compared to healthy control's serum. Higher levels of MMP9 and leptin and lower levels of adiponectin were observed in SF as compared to serum. The MMP9 in SF and MMP13 levels in serum and SF decreased in KL grade 4 cases. In these patients, higher levels of leptin and lower levels of adiponectin were observed in SF versus patients of lower grades. There was increased infiltration of CD8+ T cells in SF of OA cases with decreased frequency in grade 4 cases. The expression of CD161 on T cells was significantly higher in SF than peripheral blood with significant upregulation in grade 4 patients. The CD161 expression had significant positive correlation with IL-17 in the serum of patients. The ROC curves of CD161 expression significantly distinguished grade 2 and grade 4 patients. Collectively, an elevated CD161 expression on T cells in circulation and synovial compartment clearly distinguished lower and higher grade patients warranting studies to assess its role as a contributing factor towards OA progression.