Benefit to decrease esophageal damage using an ablation catheter with increased irrigation channels for pulmonary vein isolation

Prevention of left atrium esophagus fistula: Appraisal of existing technologies and strategies

Catheter ablation has emerged as an effective treatment for atrial fibrillation (AF). Atrial esophageal fistula (AEF) is a rare, but feared complication. With increasing utilization of ablation therapy for AF, the understanding of the relationship between AEF and ablation has been improved in recent years. Efforts to reduce the risk of AEF have focused on decreasing the risk of severe esophageal injury (EI) and the presumed subsequent progression from EI to AEF, including esophageal temperature monitoring, esophageal cooling systems, esophageal deviation devices, and decreasing and/or curtailing ablation energy delivery. Periprocedural assessment may help identify higher risk patients and detect early esophageal lesions. This review systematically summarizes and evaluates the current strategies and techniques utilized to reduce the risk of AEF in the clinical workflow for AF ablation. We expect that this review will help clinicians to better understand the principles, advantages, and disadvantages of these methods, and to find suitable strategies using current available tools.

Relevance of esophageal position and temperature on thermal injuries and rhythm outcome in atrial fibrillation ablations

BACKGROUND

Thermolesions are a dangerous complication of atrial fibrillation (AF) ablation. We aimed to assess the reasons for thermolesions and the effect of esophageal position on recurrences.

METHODS

The study included consecutive patients undergoing AF catheter ablation at Heart Center Leipzig between January and September 2014. We collected data of esophagus localization, temperature, endoscopy, and follow-up.

RESULTS

The study included 645 patients into analyses. A total of 626 (97.2%) received a temperature probe. Esophageal position was categorized: (A) behind left pulmonary veins, (B) left ostial, (C) in the middle of left atrium, (D) right ostial, and (E) behind right pulmonary veins. The most frequent esophageal position was B-C (n = 201, 32.1%), followed by B (n = 161, 25.7%), and C (n = 147, 23.5%). The temperature was highest in A-B positions (42.04°C) and in D-E positions (41.70°C). There was a significant correlation between the endoscopically detected esophageal lesions (EDEL) and the esophageal position (r² = -.115, P = .004) and the esophageal temperature (r² = .162, P = .000), but not with body mass index (BMI) (r² = -.016, P = .688). Additional substrate modification in the left atrium resulted in significantly higher esophageal temperatures (P < .001) and more frequent EDEL (P = .049). An EDEL was found in 15 patients (2.3% of all patients, 5.6% of patients receiving endoscopy). Of those, the median esophageal temperature was 41.8°C (interquartile range [IQR]: 41.2-42.4). Neither esophageal position nor temperature during ablation was associated with arrhythmia recurrences (both P > .400).

CONCLUSIONS

EDEL depended on the esophageal position and temperature, but not on BMI. Esophageal position and intraluminal temperature during ablation had no effect on recurrences.

Electrogram characteristics of the coronary sinus in cases requiring epicardial ablation within the coronary sinus for creating a conduction block at the left lateral mitral isthmus

BACKGROUND

Left lateral mitral isthmus (LLMI) linear ablation is a safe and effective technique for treating left mitral flutter. LLMI linear ablation with pulmonary vein isolation may reduce the recurrence of persistent atrial fibrillation. However, epicardial ablation within the coronary sinus (CS) is often required to create the LLMI block line. If the necessity for epicardial ablation is checked before ablation, complications may be reduced.

METHODS

We recruited 135 patients who underwent their first LLMI ablation and divided them into two groups, one group not requiring epicardial ablation for creating a conduction block at the LLMI (Endo group) and another requiring it (Epi group). These two groups were compared in terms of the electrogram characteristics of the CS.

RESULTS

Bidirectional block through the LLMI was achieved in 94.8% of patients. In 42% of these patients, not only the endocardium but also the epicardium was ablated. As for the electrogram, the Endo group had lower atrium voltage and atrioventricular voltage ratios (p = 0.009) than the Epi group before LLMI ablation. By contrast, there were no significant differences in the atrium voltage and the atrioventricular voltage ratio between these two groups after LLMI ablation.

CONCLUSIONS

For creating a conduction block at the LLMI, the atrium voltage and the atrioventricular voltage ratio in the CS before ablation are important. The atrioventricular voltage ratio is a crucial criterion for determining whether epicardial ablation is necessary; furthermore, the atrioventricular voltage ratio in the CS must be reduced with or without epicardial ablation.

Oesophageal Injury During AF Ablation: Techniques for Prevention

Atrial fibrillation remains the most common arrhythmia worldwide, with pulmonary vein isolation (PVI) being an essential component in the treatment of this arrhythmia. In view of the close proximity of the oesophagus with the posterior wall of the left atrium, oesophageal injury prevention has become a major concern during PVI procedures. Oesophageal changes varying from erythema to fistulas have been reported, with atrio-oesophageal fistulas being the most feared as they are associated with major morbidity and mortality. This review article provides a detailed description of the risk factors associated with oesophageal injury during ablation, along with an overview of the currently available techniques to prevent oesophageal injury. We expect that this state of the art review will deliver the tools to help electrophysiologists prevent potential oesophageal injuries, as well as increase the focus on research areas in which evidence is lacking.