Can oesophageal temperature probes prevent oesophageal injury during catheter ablation of atrial fibrillation?

Abstract

BACKGROUND: Radiofrequency catheter ablation of the posterior left atrium has the potential for oesophageal injury. Multi-electrode oesophageal temperature probes (OTP) are used to help monitor oesophageal heating. This study aimed to determine oesophageal tissue and OTP recorded temperatures associated with 1) high-power, short-duration (HPSD) vs low-power, long-duration (LPLD) ablation, and 2) uninsulated vs insulated OTP. METHODS: A gel and thermochromic phantom model of the left atrium and oesophagus was used to assess heating kinetics. A clinically used OTP was placed into the model oesophagus to record temperatures during ablation. Irrigated ablations were performed at 30 W/20 s (LPLD), and compared with 50 W/5 s (HPSD), and lesion temperature mapping with digital photography was performed. RESULTS: The HPSD vs LPLD had a lower peak oesophageal temperature (Tpeak) (39.17+/-0.06 degreeC vs 41.73+/-0.12 degreeC; p<0.0001) and a lower discrepancy in OTP measurements (5.13+/-0.23 degreeC; p<0.0001 vs 7.20+/-0.14 degreeC; p<0.0001) (Panels A and B). The HPSD created shallower lesions than LPLD (2.49+/-0.04 mm vs 3.74+/-0.23 mm; p=0.0008). Heating around the OTP was observed, particularly in LPLD ablations with greater overshoots above the cut-off of 38.5 degreeC (3.23+/-0.16 degreeC vs 0.67+/-0.06 degreeC; p<0.0001), and was minimised by insulation (41.73+/-0.12 degreeC vs 39.13+/-0.25 degreeC; p<0.0001) (Panels B and C). CONCLUSIONS: LPLD ablation can cause more oesophageal heating and is more difficult to monitor due to greater discrepancy in OTP temperature. Insulation of OTP reduces oesophageal heating.