Presence of passive electric current (antenna effect) during radiofrequency application in supraventricular arrhythmia ablation
Atrial fibrillation; Esophageal perforation; Esophageal disease; Radiofrequency ablation; Catheter ablation; Esophageal monitoring
Introduction: esophageal thermal injury is a complication secondary to the application of radiofrequency (RF) during ablation of atrial fibrillation. To prevent such injury, the increase in esophageal temperature can be monitored by means of metal-tipped probes. However, placing the ablation catheter and probe under the same electromagnetic field may contribute to esophageal injury by passive energy generation (antenna effect). Objective: To evaluate whether the presence of a metal probe placed within the electromagnetic field created by RF could heat the esophagus due to the antenna effect. Method: 30 patients diagnosed with supraventricular tachycardia underwent ablation with RF application and esophageal temperature monitoring with a metal-tipped probe. Uniand bipolar voltage, electric current, current density, power, programmed power in the RF device, distance from the tip of the ablation catheter to the tip of the metal probe, and esophageal temperature were recorded before (PRE), during (ON), and after (POST) RF ablation. Results: During RF application, there was a significant increase in bipolar voltage (12.3%), unipolar voltage (67.1%), electric current (11.2%), density (11.1%) and power (14.5%). Changing the distance between the tip of the ablation catheter and the tip of the metal probe did not contribute to the effect, and the esophageal temperature remained unchanged. Conclusion: during the RF ablation process, there was passive electric current generation at the tip of the metal probe without an increase in esophageal temperature.