Long-term mobility of the esophagus in patients undergoing catheter ablation of atrial fibrillation: data from computer tomography and 3D rotational angiography of the left atrium

Preoperative Personalization of Atrial Fibrillation Ablation Strategy to Prevent Esophageal Injury: Impact of Changes in Esophageal Position

INTRODUCTION

Due to changes in esophageal position, preoperative assessment of the esophageal location may not mitigate the risk of esophageal injury in catheter ablation for atrial fibrillation (AF). This study aimed to assess esophageal motion and its impact on AF ablation strategies.

METHODS AND RESULTS

Ninety-seven AF patients underwent 2 computed tomography (CT) scans. The area at risk of esophageal injury (AAR) was defined as the left atrial surface ≤3 mm from the esophagus. On CT1, ablation lines were drawn blinded to the esophageal location to create 3 ablation sets: individual pulmonary vein isolation (PVI), wide antral circumferential ablation (WACA), and WACA with linear ablation (WACA+L). Thereafter, ablation lines for WACA and WACA+L were personalized to avoid the AAR. Rigid registration was performed to align CT1 onto CT2, and the relationship between ablation lines and the AAR on CT2 was analyzed. The esophagus moved by 3.6 [2.7 to 5.5] mm. The AAR on CT2 was 8.6 ± 3.3 cm² , with 77% overlapping that on CT1. High body mass index was associated with the AAR mismatch (standardized β 0.382, P <0.001). Without personalization, AARs on ablation lines for individual PVI, WACA, and WACA+L were 0 [0-0.4], 0.8 [0.5-1.2], 1.7 [1.2-2.0] cm² . Despite the esophageal position change, the personalization of ablation lines for WACA and WACA+L reduced the AAR on lines to 0 [0-0.5] and 0.7 [0.3-1.0] cm² (P <0.001 for both).

CONCLUSION

The personalization of ablation lines based on a preoperative CT reduced ablation to the AAR despite changes in esophageal position. This article is protected by copyright. All rights reserved.

High incidence of (ultra)low oesophageal temperatures during cryoballoon pulmonary vein isolation for atrial fibrillation

Background

Low oesophageal temperatures (OTs) during cryoballoon pulmonary vein isolation (PVI) have been associated with complications. This study assessed the incidence of low OT in clinical practice during cryoballoon PVI and verified possible predictive values for low OT.

Methods

Consecutive patients who underwent PVI using the second-generation cryoballoon were retrospectively included. The distance from the oesophagus to the different pulmonary veins (PVs) (OP distance), body mass index (BMI), sex, age, balloon temperature and application time were studied as potential predictors of low OTs. Computed tomography was performed before the procedure to determine the OP distance. OT was measured using an oesophageal temperature probe. Applications were ended prematurely if the OT reached <16 °C. Low and ultralow OT were defined as OT <20 and <16 °C respectively.

Results

Two hundred and four patients were included. Low OT was observed in 54 patients (26%) and 27 patients (13%) reached ultralow OTs. OP distance was the only predictor of low OTs after multivariate analysis. A cut-off value of 19 mm showed 96.2% sensitivity and 37.8% specificity in predicting low OTs. No clinically relevant relation was found between low OTs and BMI, age, sex, balloon temperature or application duration.

Conclusions

The incidence of low OT was 26% for cryoballoon PVI. OP distance was the only predictor of low OTs. Since an OP distance <19 mm was present in all patients in at least one PV, we recommend routine OT measurement during PVI cryoballoon therapy to prevent oesophagus-related complications.

Prevention of Esophageal Damage During Ablation of Atrial Fibrillation by the Esophagus Mechanical Deviation

Atrial fibrillation is the most prevalent arrhythmia in the world population. Despite the use of antiarrhythmics, it is difficult to control clinically, causing symptoms and mainly generating risk of a thromboembolic event. Since 1998, by means of radiofrequency ablation, the treatment of atrial fibrillation has completely changed, but together with this important evolution complications from this ablative treatment technique have also started. In addition to the pulmonary vein stenosis caused by the ablation and later corrected with the change in the technique, atrioesophageal fistulas appeared due to the application of radiofrequency in the posterior wall of the left atrium. This wall is very close (0.5 cm onaverage) to the esophagus, which facilitates the formation of the fistula that leads to the death of almost 100% of the affected patients, despite the various treatment measurements already developed. To avoid this serious complication, several authors have created techniques to protect the esophagus including its mechanical deviation to a region opposite to the radiofrequency application, taking advantage of its mobility and easiness of handling. The mechanical deviation of the esophagus has proven to be the simplest, cheapest and most efficient way to protect this organ from radiofrequency thermal damage during atrial fibrillation ablation.

Prevenção de Dano Esofágico Durante Ablação de Fibrilação Atrial por Desvio Mecânico do Esôfago

A fibrilação atrial é a arritmia de maior prevalência na população mundial. Apesar do uso de antiarrítmicos, é de difícil controle clínico, ocasionando sintomas e principalmente gerando risco de um evento tromboembólico. A partir de 1998, por meio da ablação por radiofrequência, o tratamento da fibrilação atrial mudou completamente, porém junto a essa importante evolução também iniciaram as complicações advindas dessa técnica de tratamento ablativo. Além das estenoses das veias pulmonares causadas pela ablação e posteriormente corrigidas com a mudança da técnica, surgiram as fístulas átrio-esofágicas, devido à aplicação de radiofrequência na parede posterior do átrio esquerdo. Esta parede está bem próxima (0,5 cm em média) do esôfago, facilitando a formação da fístula que leva à morte quase 100% dos pacientes acometidos, apesar das diversas medidas de tratamento já desenvolvidas. Para evitar essa grave complicação, vários autores criaram técnicas para proteger o esôfago incluindo seu desvio mecânico para uma região oposta à da aplicação de radiofrequência, aproveitando a sua mobilidade e facilidadede abordagem. O desvio mecânico do esôfago tem se mostrado a forma mais simples, barata e eficiente de proteger esse órgão da lesão térmica da radiofrequência durante a ablação da fibrilação atrial.

Esophageal positions relative to the left atrium; data from 293 patients before catheter ablation of atrial fibrillation

Aims

Three-dimensional rotational angiography (3DRA) of the left atrium (LA) and the esophagus is a simple and safe method for analyzing the relationship between the esophagus and the LA during catheter ablation of atrial fibrillation. The purpose of this study is to describe the location of the esophagus relative to the LA and mobility of the esophagus during ablation procedure.

Methods

From 3/2011 to 9/2015, 3DRA of the LA and esophagus was performed in 326 patients before catheter ablation of atrial fibrillation. 3DRAwas performed with visualization of the esophagus via peroral administration of a contrast agent. The positions of the esophagus were determined at the beginning of the procedure, for part of patients also at the end of procedure with contrast esophagography.

Results

The most frequent position is behind the center of the LA (91 pts., 31.9%) The least frequent position is behind the right pulmonary veins (27 pts., 9.4%). The average shift of the esophagus position was 3.36 ± 2.15 mm, 3.59 ± 2.37 mm and 3.67 ± 3.23 mm for superior, middle and inferior segment resp.

Conclusions

The position of the esophagus to the LA is highly variable. The most common position of the esophagus relative to the LA is behind the middle and left part of the posterior wall of the LA. The least frequently observed position is behind the right pulmonary veins. No significant position change of esophagus motion from before to after the ablation procedure in the majority (≥95%) of the patients was observed.

Catheter ablation of paroxysmal atrial fibrillation: circumferential pulmonary vein ablation: success rates with and without exclusion of areas adjacent to the esophagus

BACKGROUND

Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory paroxysmal atrial fibrillation. Circumferential pulmonary vein ablation is still the standard approach in these patients. The occurrence of an atrioesophageal fistula is a rare but life-threatening complication after such ablation procedures. This is due to the fact that the esophagus does frequently have a very close anatomical relationship to the left or right pulmonary vein ostia. The aim of our study was to evaluate whether the exclusion of areas adjacent to the esophagus does have a significant effect on the success rate after circumferential pulmonary vein ablation.

METHODS

Two hundred consecutive patients [121 men, 69 women; mean age 59.1 years (SD ± 11.3 years)] with symptomatic paroxysmal atrial fibrillation underwent a circumferential pulmonary vein ablation procedure (using the CARTO- or the NAVX-system). In 100 patients, a complete circumferential pulmonary vein ablation was attempted regardless of the anatomical relationship between the ablation sites and the esophagus (group A). In the remaining 100 patients, the esophagus was marked by a special EP catheter and areas adjacent to the esophagus were excluded from the ablation procedure. After discharge, patients were scheduled for repeated visits at the arrhythmia clinic at 1, 3, 6, 9, 12, 24 and 36 months after the ablation procedure.

RESULTS

The ablation procedure could be performed as planned in all 200 patients. In group A, all pulmonary veins could be isolated successfully in 88 out of 100 patients (88%). A mean number of 3.9 pulmonary veins (SD ± 0.37 PVs) were isolated per patient. The 12 cases of an incomplete pulmonary vein isolation were due to poorly accessible pulmonary vein ostia. In group B, all pulmonary veins could be isolated successfully in only 58 out of 100 patients (58%; P < 0.01). A mean number of 3.5 PVs (SD ± 0.6 PVs) were isolated per patient (P < 0.01). This was mostly due to a close anatomical relationship to the esophagus. The ablation strategy had to be modified in 46/100 patients in group B because of a close anatomical relationship between the right (n = 25) or left (n = 21) pulmonary vein ostia and the esophagus. One year after the ablation procedure, 87% of patients in group A (87/100) and 79% of patients in group B (79/100) were free from an arrhythmia recurrence (P = 0.19). Three years after catheter ablation, the success rate was 80% (no arrhythmia recurrence in 80 out of 100 patients) in group A and 66% in group B (no arrhythmia recurrence in 66 out of 100 patients; P = 0.04). There were no major complications during long-term follow-up.

CONCLUSIONS

The exclusion of areas adjacent to the esophagus results in a markedly higher percentage of incompletely isolated pulmonary veins after circumferential pulmonary vein ablation procedures. This results in a significantly higher arrhythmia recurrence rate during long-term follow-up.