| Objective:Radiofrequency ablation has been developed as an effective method for the treatment of arrhythmia, but more and more people pay attention has been paid to the serious complications of this technique. Atrial esophageal fistula is a rare but serious complication of radiofrequency catheter ablation for atrial fibrillation, which is associated with a high mortality rate. Understanding the structure of left atrium, pulmonary vein and coronary sinus before operation can prevent the occurrence of this complication. In this study, the anatomical relationship of esophagus and major structures involved in electrophysiological ablation were analyzed with the value of the above tissue structure was measured by multi-slice spiral CT, which was helpful for the choice of ablation types and energy, therefore provided the anatomical basis for the successful treatment of radiofrequency ablation, and then it was helpful to the choice of ablation type and energy and the prevention of complications. Methods:100 patients who underwent coronary artery angiography(CTA)were analyzed retrospectively, including 57 males, 43 females, aged 45~65 years. The following diameters were measured by two independent experienced senior radiologists with double blind method : the shortest distance between esophageal edge to 4 pulmonary vein ostia, the esophageal maximum diameter, the thoracic anteroposterior diameter, and the maximum anteroposterior diameter of left atrial at the level of inferior pulmonary veins; the great cardiac vein diameter and esophageal wall thickness at the contact between the esophagus and the CS/GCV; the diameter of coronary sinus orifice, and the distance between esophagus and coronary sinus orifice. The correlation was analyzed between pulmonary veins and left atrial diameter, and between the maximum esophagus diameter and the thoracic anteroposterior diameter. The fat pads were observed between the esophagus and the left atrium for continuity and the thickness of the fat pads were measured. On the basis of the above measurements, the patients were classified into 2 different groups:(1) Based on the distance of transphagus at atrial segment to the left and right pulmonary veins, the esophagus were divided into two types, each of which was subdivided into a, b, c three subtypes.(2) Based on whether it was immediate contact with the coronary sinus, the esophagus was divided into two types. SPSS 20.0 statistical software was used for statistical analysis.. Results:The mean anteroposterior diameter of the left atrium was 37.27±6.58 mm, the maximum diameter of the esophagus at the inferior pulmonary vein level was 19.11±3.77 mm, the anteropostior diameter of throx at the inferior lower pulmonary vein level was 120.69±16.00 mm. The correlation analysis between the distances from esophagus to the pulmonary veins and anteroposterior diameter of left atrium, and between the esophagus maximum diameter at the inferior pulmonary vein level and anteroposterior diameter of the throx, showed that only the distance of the esophagus to the left superior pulmonary had a weak correlation with the anteroposterior thoracic diameter, and the distance of esophagus to the left inferior pulmonary vein had a weak correlation with the anteroposterior diameter of left atrium.The shortest distance from the outer edge of esophagus to the left superior pulmonary vein, left inferior pulmonary vein, right superior pulmonary vein, right inferior pulmonary vein is 7.27±3.44 mm, 5.14±4.06 mm, 24.36±8.21 mm, 13.22± 6.82 mm, respectively. The difference of the distance among the groups was statistically significant(P<0.05). The esophagus had a relative far distance with the right superior pulmonary vein, but had a more close relationship to the left pulmonary veins.Based on the shortest distance between the pulmonary veins and the esophagus, the patients were classified as: type 1a in 57 patients( 57%), type 1b in 19 patients( 19%), type 1c in 4 patients(4 %), type 2a in 5 patients(5 %), type 2b in 15 patients(15 %), type 2c in 0 patient( 0%). A relative close relationship from the esophase to the left pulmonary veins exist in the patients in type 1, and a more close relationship between the esophagus and right pulmonary veins exist in the patients in type 2. Overlaping between the distances from the esophagus to the right and left pulmonary veins were observed in some cases, including 2 patients in type 1 showing the distance of less than 5 mm from the esophagus to the right inferior pulmonary pulmonary vein, and 4 patients in cases type 2 showing the distance of less than 5 mm from the esophagus to the left superior pulmonary vein.Based on whether the esophagus was immediate contact with CS or GCV, 1 / 4(25 cases) patients were classified as type A showing a direct contact between the esophagus with CS or GCV. Among the patients who had non-direct contact between the esophageal and CS or GCV, the distance from the esophagus to the GCV ranged from 1.013 mm to 14.71 mm. In group A, the diameter in CS ostium was 12.52±1.99mm; the GCV diameter was 7.55±1.77 mm; the distance between the esophagus and CS distance was 15.1±4.4 mm,; the wall thickness of the esophagus at the nearest contact with GCV was 3.38±1.03 mm. In group B, the diameter in CS ostium was 13.17±2.85mm; the GCV diameter was 8.25±2.39mm; the wall thickness of the esophagus at the nearest contact with GCV was 3.47±0.90 mm. The distance from the esophagus to the CS ostium between group A and B was statistically(P < 0.05). No significant differences were found in the CS ostium diameter, the GCV, diameter and the wall thickness of the esophagus between the 2 groups. Conclusions:Esophagus anatomy varied among individuals, and, the classification of the esophagus based on the multislice spiral CT images would be helpful for assessing the anatomical, relationship of esophagus with adjacent pulmonary veins, left atrium and CS. Clarification of the esophageal anatomy and its close proximity to the adjacent structures would be of great significance in guiding the ablative targets, choosing ablative stragetries, and reducing the complication of esophageal injury druing the radiofrequency catheter ablation for cardiac arrhythmia. |
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