Factors associated with periesophageal vagal nerve injury after pulmonary vein antrum isolation

Abstract

Background: Periesophageal vagal nerve injury is recognized as a rare complication in atrial fibrillation ablation procedures. We investigated the factors associated with the occurrence of symptomatic periesophageal vagal nerve injury after pulmonary vein antrum isolation.

Methods and results: Overall, 535 consecutive patients who underwent sole pulmonary vein antrum isolation were included. Point-by-point radiofrequency applications were applied using irrigated-tip catheters under minimal sedation without esophageal temperature monitoring. In the initial 165 patients, the ablation settings for the posterior left atrium were a maximum energy of 25 to 30 W and a duration of 30 seconds. In the subsequent 370 patients, the power was additionally limited to 20 to 25 W at specific parts of the posterior left atrium where the ablation line transversed the esophagus. Symptomatic gastric hypomotility was found in 13 patients, and all were observed during the initial period (7.9%). No other collateral damage was observed. Logistic regression analysis revealed that the body mass index was the only independent predictor for identifying patients with gastric hypomotility (odds ratio 0.770; 95% confidence interval 0.643 to 0.922; P=0.0045) during the initial period. The prevalence of gastric hypomotility was significantly higher in the initial study period than subsequently (0 of 370, 0%; P<0.0001). All except for 1 patient recovered completely with conservative treatment within 4 months after the procedure.

Conclusions: Periesophageal vagal nerve injury is more common collateral damage than direct esophageal injury in pulmonary vein antrum isolation procedures. Titrating the radiofrequency energy at specific areas where the ablation line transverses the esophagus and taking account of the body mass index might reduce occurrences not only of direct esophageal damage but also of periesophageal vagal nerve injury in pulmonary vein antrum isolation procedures.

Keywords: atrial fibrillation; catheter ablation; collateral damage; complication; periesophageal vagal nerve injury; pulmonary vein isolation.

Figure 1.

Representative esophagraphy and pulmonary venography. A, Esophagrams reveal the esophageal courses. B, Pulmonary venography shows the anatomy of the PV antrum. AP indicates anteroposterior view; Eso, esophagus; LA, left atrium; LAO, left oblique view; LIPV, left inferior PV; LSPV, left superior PV; PV, pulmonary vein; RIPV, right inferior PV; RSPV, right superior PV.

Figure 2.

A, A point‐by‐point RF ablation line on the posterior LA is shown on the pulmonary venography image. B, A point‐by‐point circumferential ablation line is shown on a 3‐dimensional mapping system (CARTO3). Each dot indicates 1 RF application with a duration of 30 seconds. The pink dots show the ablation points on the anterior part of the PVs, and the red (longitudinal line) and yellow dots (transverse line) show the ablation points on the posterior LA. After August 2011, the energy power was limited to 20 to 25 W at the sites where the ablation line transversed the esophagus (yellow dots). AP indicates anteroposterior view; CRA, cranial view; LA, left atrium; LIPV, left inferior PV; LPVs, left pulmonary veins; LSPV, left superior PV; PA, posteroanterior view; PV, pulmonary vein; RF, radiofrequency; RPVs, right pulmonary veins.

Figure 3.

Representative images of gastric hypomotility resulting from AF ablation. A, Abdominal x‐rays taken on the day after catheter ablation show dilatation of the stomach and massive amounts of retained food (left image: case 13; right image: case 11). The red arrows show the contour of the dilated stomach. Note that the contrast medium used in the esophagraphy during the procedure is still retained in the stomach on the next day (right image). B, Massive amounts of retained food were found by gastric endoscopy despite an overnight period of fasting even 28 months after the ablation procedure (case 5).

Figure 4.

Representative axial images of the esophagus and posterior LA at the level of the left inferior PV. A, Cases without periesophageal vagal nerve injury. The distance between the LA and esophagus is 3.0 mm (left) and 3.7 mm (right), respectively. B, Cases with periesophageal vagal nerve injury (left image: case 2; right image: case 11). The distance between the LA and esophagus is 3.9 mm (left) and 3.1 mm (right), respectively. There was no significant difference in the LA–esophagus distance between the patients with and without periesophageal vagal nerve injury. Ao indicates descending aorta; Eso, esophagus; LA, left atrium; LIPV, left inferior PV.