Abstract 345 Single versus multiple esophageal temperature sensor electrode for cryoballoon pulmonary vein isolation

Background: Thermal esophageal injury is a known complication of balloon based PVI due to collateral thermal damage of the esophagus due to its closeness to the pulmonary veins (PVs). Continuous esophageal temperature monitoring is performed during PVI to increase safety during CB-based PVI. The novel POLARx CB (Boston Scientific, St. Paul, MN, USA) ablation system provides an esophagus temperature probe with a single detector at its tip. Clinical data evaluating the accuracy of its measurement is scarce.

Objective: We report about our initial experience comparing the Esophageal Temp Sensor Cable (ETS) of the POLARx CB in comparison with the CIRCA S-CATH™ (CIRCA Scientific, Englewood, Colorado, U.S.) esophagus temperature probe with multiple detectors.

The ETS of the POLARx CB contains a single temperature sensor at the distal end of the probe in comparison to the CIRCA S-CATH™ probe, which has an array of 12 temperature sensors shaped as an “S” form. Therefore, this probe provides wider esophageal coverage for temperature detection.

Methods and Results: We present a case series of 6 patients with symptomatic atrial fibrillation (AF) who underwent PVI utilizing the novel POLAR-X CB. All CB procedures were performed with continuous esophagus temperature monitoring with the CIRCA S-CATH™ temperature sensor, as well as with the ETS probe of the POLARx balloon.

The ETS probe of the POLAR-X CB showed higher esophagus temperature measurements in comparison to the CIRCA S-CATH™ temperature sensor. We observed significant temperatures differences between the two probes, with a maximum difference of 21.3 °C during CB-based isolation of a right inferior PV (RIPV): measuring a temperature of 32.0 °C by the ETS vs. 10.7 °C by the CIRCA S-CATH™ probe in one case. One patient (case 6) with a maximal temperature difference of 18.3 °C on the LSPV was diagnosed with an esophagus ulceration 3 days after the ablation.

Temperature differences were significant during isolation were detected during isolation of the left superior PV (LSPV) at 7.5 (4.9; 712.8; p<0.05) °C (median and interquartile range), followed by the left inferior PV (LIPV) at 1.6 (0.5; 5.7; p<0.05) °C; the RIPV at 0.0 (0; 0.3; p<0.05) °C. Temperature difference of measurements of the right superior PV (RSPV) were not significant 0.5 (0.1; 0.9; p=0.82) °C.

Conclusions: Significantly higher esophageal temperatures can be observed when using a single esophageal temperature sensor electrode as compared to a multiple esophageal temperature sensor electrode, which might fail to prevent possible esophageal thermal lesions.

	Circa S Temperature					Boston Temperature					Temp Difference
	LSPV	LIPV	RSPV	RIPV	LCPV	LSPV	LIPV	RSPV	RIPV	LCPV	LSPV	LIPV	RSPV	RIPV	LCPV
1	15	18,7	35,6	35,8	-	26	23	36	36	-	11	4,3	0,4	0,2	-
2	26,5	27	35,4	35,2	-	27	34	35	35		0,5	7	-0,4	-0,2	-
3	26,2	35,4	34	10,7	-	34	34	34	32	-	7,8	-1,4	0	21,3	-
4	35,2	35,5	35	35,2	-	36	36	35	35,2	-	0,8	0,5	0	0	-
5	24,9	13,9	36	35	-	32	33	36	36	-	7,1	19,1	0	1	-
5b	26,7	-				33					6,3				-
6	16,0	34,4	35,4	35,2	-	36,0	36,0	36,0	36,0	-	20	1,6	0,6	0,8	-
6b	17,7	35,5				36,0	36,0				18,3	0,5			-

Table 1. Temperature measurements (°C) with the ETS probe of the POLARx ablation system, with the CIRCA S-CATH™ temperature probe, and temperature differences between the two probes (ETS POLAR X Temperature – CIRCA S-CATH™ Temperature). Case 5b and 6b show measurements during bonus freezes.