Balloon Catheter Position and its Relationship with Esophageal Temperature during Pulmonary Vein Isolation using High-Intensity Focused Ultrasound

BACKGROUND: HIFU can achieve PVI, but severe esophageal complications have happened. We analyzed relative position of HIFU balloon catheter (BC) to esophageal temperature (ET) probe and correlated it to ET changes. METHODS AND RESULTS: Before each ablation relative position of HIFU BC to ET probe was recorded in RAO 30º and LAO 40º. We compared ablations where ET at end of ablation was <38.5ºC or ≥38.5ºC and <40.0ºC or ≥40.0ºC. A total of 600 images from 311 ablations in 28 patients (18 male, age 63±7 years), were analyzed. ET ≥38.5ºC was reached when distance from BC to ET probe was: <20mm in LAO for RSPV and <29mm in LAO for RIPV. For RIPV ET ≥38.5ºC was reached when angle between BC and ET probe was significantly smaller in LAO and RAO. ET ≥40.0ºC was reached when distance of BC to ET probe was: <20mm in LAO for RIPV, <14mm in RAO for RIPV, <18mm in RAO for LIPV. ET increased to ≥40.0ºC when distance from BC to ET probe was significantly longer in LAO for LIPV. For RIPV ET ≥40.0ºC was reached when angle between BC and ET probe was significantly smaller in LAO. CONCLUSION: There is a relationship between distance/angle of HIFU BC to ET probe and ET: shorter distances and smaller angles can cause higher ET.