A40 Session 11: Cardiovascular Disease Intervention: A new cryo balloon efficacy and safety monitoring: Distal balloon impedance and temperature recording

Abstract

Presently pulmonary vein (PV) occlusion (OCCL), ice formation and thickness monitoring is lacking. It was hypothesized that measurement of the impedance (Imp) and temperature (T) at the front of the Cryo balloon can be calibrated to measure PV OCCL, ice formation and thickness. One mm thick ring electrode and Thermocouple sensor were placed on the balloon shaft adjacent to the anterior surface of the balloon with a reference electrode behind it. Continuous Imp (using 12.5 kHz electrical current) and T measurements were made throughout Cryo in a T constant bath, constant 5 mmHg pressure perfused superior vena cava (SVC) – right atrium (RA) setup and intact hearts’ PV (2 pigs and 2 canine). Ice thickness was assessed with 1.5–3.6 MHz ultrasound transducer and directly in the SVC circulating bath. Electrical isolation was used to define efficacy in the intact hearts. As shown in the figure below, circumferential OCCL caused the Imp to rise rapidly with T crossing the 0 °C mark beginning 60 s (sec) into Cryo and continued until saturation at 2000 ohms ( Ω ) and −37.8 ± 3.3 °C at 120 ± 25 s. Without OCCL, Imp did not rise above 500 Ω, with the T reaching only −9.2 ± 12.1 °C. Ice thickness was measured on the epicardial SVC tissues growing significantly starting at 60 s. into Cryo before stabilizing at 3 ± 0.5 mm. Impedance rose 950 Ω in chronic PV sleeve ablations. (Panel B). 1. The use of Imp and distal T provides evidence of OCCL. 2. Ice thickness correlates with Imp if OCCL is present. 3. PV isolation was achieved with 3 mm of ice formation and Imp rise of >2000 Ω.