Differences in Transient Thermal Response of Commercial Esophageal Temperature Probes: Insights From an Experimental Study

Objectives: The purpose of this study was to evaluate the differences in transient thermal response (TTR) among various types of commercial esophageal temperature probes (ETPs) in the United States in an experimental model. Background: There is little information regarding the variation in TTR among various commercial ETPs that are approved for atrial fibrillation ablation. Methods: We compared various thermodynamic characteristics including, mean thermal time constant (τ), time to rise 1°C (T_1°C), time to peak temperature (T_peak), and decay time among 22 different ETPs. Each probe was submerged in a constant-temperature water bath maintained at 37 ± 0.5°C and then quickly (<0.5 s) submerged into another water bath at 45 ± 0.5°C. The experiments were repeated 3 times with each probe. TTR properties were compared on the basis of probe size, design, and number of sensors. Results: The τ was significantly higher with the larger 24- and 18-F ETPs compared with the smaller 9-F ETPs. Compared with the 18-F probe, T_1°C (11.9 s vs. 5 s), T_peak (40.3 s vs. 14.4 s), and T_decay (92.4 s vs. 32.4 s) was shorter with the 9-F ETPs. Solid-shaft ETPs had shorter τ (8.6 s vs. 20.5 s), T_1°C (4.4 s vs. 10.1 s) and T_peak (13.5 s vs. 32.5 s) compared with acoustascopes. Multisensor ETPs had shorter τs (3.9 s vs. 9.1 s), T_1°C (2.3 s vs. 5 s), and T_peak (6.2 s vs. 14.4 s) compared with single-sensor ETPs. Conclusions: There is a significant variation in TTR among the various commercially available ETPs. The use of certain ETPs might result in underestimation of luminal esophageal temperature, which can potentially lead to adverse events.