Abstract 3230: Mechanism of Chest Pain Occurring During Radiofrequency Ablation on the Posterior Left Atrium in Patients with Atrial Fibrillation
Introduction: The mechanism of chest pain occurring during radiofrequency (RF) energy applications to the posterior left atrium (LA) is still unclear. We recently developed an esophageal cooling method (ECO) with a cooled water-irrigated intraesophageal cooling balloon in an attempt to prevent atrioesophageal fistulas, and reported that it could suppress chest pain occurring during RF ablation on the posterior LA in patients with atrial fibrillation (AF). The present study aimed to examine the mechanism of the chest pain.
Methods: Seventeen patients with drug-refractory AF (male 16, 56 ± 12 years) who underwent circumferential pulmonary veins isolation under conscious sedation were included in this study. RF energy (30W) was delivered to the posterior LA two times including during the control, with ECO. For every RF energy application, the patient was asked what the magnitude of the chest pain was during the RF energy application, in which the magnitude of the chest pain was expressed by a number ranging from 0 to 10 depending on the patient’s subjective feelings (chest pain score). In the control and during the ECO, the luminal esophageal temperature (LET) was measured with an intraesophageal probe placed at a site close to the tip of the ablation catheter while the LA temperature (LAT) was measured at the tip of the ablation catheter.
Results: At baseline, ECO lowered the LET from 36.9 ± 0.6°C to 29.9 ± 3.2 °C (p<0.01). The chest pain score decreased from 7.5 ± 2.6 with a maximal LET of 39.2 ± 1.9°C in the control to 3.6 ± 2.9 (p< 0.01) with a maximal LET of 31.7 ± 4.4 °C (p<0.01) during the ECO. There was no correlation between the LAT and LET at baseline or during RF ablation both during the control and ECO, suggesting that the ECO did not affect the endocardial LA temperature. Although the chest pain score did not correlate with either the maximal LET or maximal LAT in the control, or with the maximal LET during the ECO, it slightly correlated with the maximal LAT during the ECO (r=0.35, p=0.005).
Conclusions: The mechanism of the chest pain occurring during RF ablation on the posterior LA was the heating of both the esophagus and LA wall.