Origin of the atrial electrogram recorded from the esophagus

Area of Science:

• Electrophysiology
• Cardiac Anatomy

Background:

• The origin of atrial electrograms recorded by esophageal leads during tachycardia is not fully understood.
• Accurate localization of accessory pathways is crucial for successful ablation in Wolff-Parkinson-White syndrome.

Purpose of the Study:

• To determine the source of atrial electrograms recorded on esophageal leads.
• To evaluate the utility of esophageal leads in mapping atrial activation and locating accessory pathways.

Main Methods:

• Mapping of the atria and esophagus during reciprocating tachycardia and ventricular pacing.
• Recording atrial electrograms at 1-cm intervals throughout the esophagus.
• Analyzing ventriculoatrial (VA) conduction times from esophageal lead positions.

Main Results:

• Distal esophageal atrial electrograms correlated with atrial septal depolarization.
• Shortest esophageal VA conduction times were typically recorded at the distal lead position.
• Left atrial activation was rarely identifiable in the esophagus; esophageal leads were ineffective for left-sided pathway localization.

Conclusions:

• The distal esophageal atrial electrogram likely represents posterior paraseptal atrial depolarization.
• Clear identification of left atrial activation via esophageal leads is uncommon.
• Esophageal leads are not a reliable tool for locating left-sided accessory pathways.