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Abstract

Funding Acknowledgements Type of funding sources: None. Background Thermal latency, or delayed heating, is increasingly recognized as an important factor in the formation of both intentional and unintentional lesions during radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF). High-power short-duration (HPSD) ablation appears to have greater thermal latency than low or medium power ablation. Proactive esophageal cooling (PEC) has been shown to reduce esophageal lesion formation under a variety of conditions by directly reducing the effects of thermal latency, but the influence of anatomic dimensions on the protective efficacy of cooling during HPSD ablation has not been investigated. Purpose Determine the impact of changes in pericardial tissue thickness on thermal latency in order to quantify the protective efficacy of PEC across a range of anatomic dimensions. Methods We created a mathematical model of the left atrium undergoing HPSD ablation, both with and without a PEC device in place, using a range of pericardial tissue thicknesses (0.5, 0.75, and 1 mm). HPSD ablation was set at 50 W for 10 s, or 90 W for 4 s. We then examined the temperature dynamics at a range of thickness, focusing on the layer of mostly fatty tissue between the atrial and esophageal walls by varying the thickness of this layer while quantifying the degree of esophageal damage using the Arrhenius equation to determine the fraction of damage after peak heating has occurred. Results Under control conditions, the growth of lesions from RF ablation at both 50 W and 90 W was found to continue for greater than 10 seconds beyond the cessation of RF energy application. Esophageal lesion formation ranged from 71% to 96% transmurality after 50 W ablation for 10 s, and from 50% to 72% transmurality after 90 W ablation for 4 s. With PEC in place, esophageal lesion transmurality was markedly reduced, with a maximum transmurality ranging from 12% to 32% with 50 W ablation, and from 2% to 20% with 90 W ablation (Figure). Increasing thickness of pericardial tissue (with simulations of 0.5, 0.75, and 1 mm) resulted in decreasing esophageal lesion transmurality (67%, 74%, and 83% at 50 W power, and 72%, 82%, and 96% at 90 W power, respectively, with the 0.5, 0.75, and 1 mm simulations). Conclusions Thermal latency with HPSD ablation contributes to lesion growth and can cause esophageal injury. Proactive esophageal cooling counteracts this effect across a range of pericardial tissue thicknesses, and reduces esophageal lesion transmurality by an average of 79%.

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... As such, these findings provide insight regarding possible mechanisms by which sequential ablation with minimal interruption has been associated with improved ablation outcomes [28]. Active esophageal cooling is performed without the need for temperature sensors, as the esophageal cooling device maintains a coolant temperature of 4 °C, and reduces the potential for esophageal wall temperatures to reach lethal isotherm levels [13,29]. As a result, premature cessation of RF energy deposition during lesion placement is unnecessary, and uninterrupted lesion placement can be performed without the need to pause for temperature alarms. ...
Article
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Background Active esophageal cooling during pulmonary vein isolation (PVI) with radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF) is increasingly being utilized to reduce esophageal injury and atrioesophageal fistula formation. Randomized controlled data also show trends towards increased freedom from AF when using active cooling. This study aimed to compare 1-year arrhythmia recurrence rates between patients treated with luminal esophageal temperature (LET) monitoring versus active esophageal cooling during left atrial ablation. Method Data from two healthcare systems (including 3 hospitals and 4 electrophysiologists) were reviewed for patient rhythm status at 1-year follow-up after receiving PVI for the treatment of AF. Results were compared between patients receiving active esophageal cooling (ensoETM, Attune Medical, Chicago, IL) and those treated with traditional LET monitoring using Kaplan–Meier estimates. Results A total of 513 patients were reviewed; 253 received LET monitoring using either single or multi-sensor temperature probes; and 260 received active cooling. The mean age was 66.8 (SD ± 10) years, and 36.8% were female. Arrhythmias were 60.1% paroxysmal AF, 34.3% persistent AF, and 5.6% long-standing persistent AF, with no significant difference between groups. At 1-year follow-up, KM estimates for freedom from AF were 58.2% for LET-monitored patients and 72.2% for actively cooled patients, for an absolute increase in freedom from AF of 14% with active esophageal cooling ( p = .03). Adjustment for the confounders of patient age, gender, type of AF, and operator with an inverse probability of treatment weighted Cox proportional hazards model yielded a hazard ratio of 0.6 for the effect of cooling on AF recurrence ( p = 0.045). Conclusions In this first study to date of the association between esophageal protection strategy and long-term efficacy of left atrial RF ablation, a clinically and statistically significant improvement in freedom from atrial arrhythmia at 1 year was found in patients treated with active esophageal cooling when compared to patients who received LET monitoring. More rigorous prospective studies or randomized studies are required to validate the findings of the current study.
... This effect is believed to stem from two primary factors. First is the direct thermal impact of cooling, which has been shown to reduce, or eliminate, the potential for esophageal tissue to reach lethal isotherm temperatures [31][32][33]. Prevention of lethal isotherm temperatures in the esophageal wall is believed to preclude development of the degree of thermal injury that may lead to an AEF weeks after the initial ablation. The second factor impacting safety is the downstream anti-inflammatory effect of cooling. ...
Article
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Introduction Radiofrequency (RF) ablation of the left atrium of the heart is increasingly used to treat atrial fibrillation (AF). Unfortunately, inadvertent thermal injury to the esophagus can occur during this procedure, potentially creating an atrioesophageal fistula (AEF) which is 80% fatal. The ensoETM (Attune Medical, Chicago, IL), is an esophageal cooling device that has been shown to reduce thermal injury to the esophagus during RF ablation. Areas covered This review summarizes growing evidence related to active esophageal cooling during RF ablation for the treatment of AF. The review presents data demonstrating improved outcomes related to patient safety and procedural efficiency and suggests directions for future research. Expert opinion The use of active esophageal cooling during RF ablation reduces esophageal injury, reduces or eliminates fluoroscopy requirements, reduces procedure duration and post-operative pain, and increases long-term freedom from arrhythmia. These effects in turn increase patient same-day discharge rates, decrease operator cognitive load, and reduce cost. These findings are likely to further accelerate adoption of active esophageal cooling.
... [23] Active esophageal cooling is performed without the need for temperature sensors, as the esophageal cooling device maintains a coolant temperature of 4 °C, and reduces the potential for esophageal wall temperatures to reach lethal isotherm levels. [13,24] As a result, premature cessation of RF energy deposition during lesion placement is unnecessary, and uninterrupted lesion placement can be performed without the need to pause for temperature alarms. Thus, a low CI can be maintained throughout the procedure, with most cases resulting in a CI well under 6, and commonly equal to zero, correlating to a higher e cacy of isolation of the pulmonary veins, and a resultant improvement in freedom from arrhythmia. ...
Preprint
Full-text available
Background: Active esophageal cooling during pulmonary vein isolation (PVI) with radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF) is increasingly being utilized to reduce esophageal injury and atrioesophageal fistula formation. Randomized controlled data also show trends towards increased freedom from AF when using active cooling. This study aimed to compare one-year arrhythmia recurrence rates between patients treated with luminal esophageal temperature (LET) monitoring versus active esophageal cooling during left atrial ablation. Methods: Data from two healthcare systems (including 3 hospitals and 4 electrophysiologists) were reviewed for patient rhythm status at one-year follow up after receiving PVI for the treatment of AF. Results were compared between patients receiving active esophageal cooling and those treated with traditional LET monitoring using Kaplan-Meier estimates. Results: A total of 513 patients were reviewed; 253 received LET monitoring using either single or multi-sensor temperature probes, and 260 received active cooling. Mean age was 66.8 (SD +/-10) years, and 36.8% were female. Arrhythmias were 60.1% paroxysmal AF, 34.3% persistent AF, and 5.6% long-standing persistent AF, with no significant difference between groups. At one-year follow-up, KM estimates for freedom from AF were 58.2% for LET monitored patients and 72.2% for actively cooled patients, for absolute increase in freedom from AF of 14% with active esophageal cooling (P=.03). Conclusions: In this first study to date of the association between esophageal protection strategy and long-term efficacy of left atrial RF ablation, a clinically and statistically significant improvement in freedom from atrial arrhythmia at one-year was found in patients treated with active esophageal cooling when compared to patients that received LET monitoring.
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