To the Editor—A double-blind case study?

Drs Liu and Wu¹ report a successful case of mechanical deviation of the esophagus using the EsoSure device during atrial fibrillation ablation with intracardiac echocardiography and a mapping system but entirely without fluoroscopy. Acute procedural success was achieved without clinical complications. We could describe this as a double-blind technique: No fluoroscopy was used during the procedure and no endoscopic examination occurred afterward. The authors therefore could not verify the effectiveness of protection or exclude the occurrence of device-related trauma.

We do not know why the authors chose mechanical deviation to protect the esophagus. There is no randomized trial evidence to support the concept, whereas trial evidence published in the past year has addressed 2 alternative approaches: The OPERA study² showed that esophageal temperature monitoring probes did not reduce thermal injury; and the IMPACT trial³ demonstrated that active thermal protection using a temperature control device (the ensoETM®; Attune Medical, Chicago, IL) reduced thermal injury by 83.4% compared to controls. No evidence of device-related esophageal trauma occurred in IMPACT, nor has any been seen in real-world registry data on the same device in 2532 ablations. The concept that underpins the method has been verified by mathematical modeling and is supported by a meta-analysis of earlier methods of cooling.³

Mechanical deviation of the esophagus has the potential to harm, and evidence of esophageal trauma has been demonstrated.⁴ Until randomized trial evidence demonstrates protection that outweighs this risk, it makes more sense to use proven alternatives. The ensoETM could easily be used without fluoroscopy, but we image for a few seconds to verify optimal positioning. Minimal use of fluoroscopy creates minimal risk, but unproven devices pose an unquantifiable danger.