TY - JOUR
T1 - Local impedance-guided radiofrequency ablation with standard and high power
T2 - Results of a preclinical investigation
AU - Osei, Kofi
AU - Sulkin, Matthew S.
AU - Hamann, Jason J.
AU - Hughes, Christopher
AU - Shuros, Allan
AU - Nagy, Tamas
AU - Kapa, Suraj
AU - Meyers, Jason
N1 - Publisher Copyright:
© 2021 Wiley Periodicals LLC
PY - 2021/8
Y1 - 2021/8
N2 - Background: Local impedance (LI) drop measured with microfidelity electrodes embedded in the tip of an ablation catheter accurately reflects tissue heating during radiofrequency (RF) ablation. Previous studies found 15–30 Ω LI drops created successful lesions, while more than 40 Ω drops were associated with steam pops. The objective of this study was to evaluate the safety and efficacy of LI-guided ablation using standard (30 W) and high-power (50 W) in a preclinical model. Methods: RF lesions were created in explanted swine hearts (n = 6) to assess the feasibility of LI-guided ablation by targeting 10, 20, or 30 Ω (n = 20/group) drops. Subsequently, LI-guided ablation was evaluated in a chronic animal model (n = 8 Canines, 25–29 kg, 30/50 W). During the index procedure point-by-point intercaval line ablation and left inferior pulmonary vein (PV) isolation were performed. RF duration was at the operators’ discretion but discontinued early if a 15–30 Ω drop was achieved. Operators attempted to avoid LI drops of more than 40 Ω. At 1-month, durable conduction block was evaluated with electroanatomic mapping followed by necropsy and histopathology. Results: In explanted tissue, terminating ablation at 10, 20, or 30 Ω LI drops created statistically larger lesions (p <.05; 1.8 [1.6–2.4] mm, 3.3 [3.0–3.7] mm; 4.9 [4.3–5.5] mm). LI-guided high-power ablation in vivo significantly reduced RF duration per application compared to standard-power (p <.05; intercaval: 8.9 ± 5.2 vs. 18.1 ± 11.0 s, PV: 9.6 ± 5.4 vs. 23.2 ± 10.3 s). LI drops of 15–40 Ω were more readily achievable for high-power (90.1%, 318/353) than standard-power (71.7%, 243/339). All intercaval lines and PV isolations were durable (16/16) at 1-month. Necropsy revealed no major collateral injury to the pericardium, phrenic nerve, esophagus, or lungs. There was no pericardial effusion, stroke, tamponade, or PV stenosis. Vagal nerve injury was found in two 30 W animals after using 19.7 ± 13.9 and 19.5 ± 11.8 s RF applications. Conclusion: LI-guided ablation was found to be safe and efficacious in a chronic animal model. High-power ablation more readily achieved more than 15 Ω drops, reduced RF duration compared with standard-power, and had no major RF collateral injury.
AB - Background: Local impedance (LI) drop measured with microfidelity electrodes embedded in the tip of an ablation catheter accurately reflects tissue heating during radiofrequency (RF) ablation. Previous studies found 15–30 Ω LI drops created successful lesions, while more than 40 Ω drops were associated with steam pops. The objective of this study was to evaluate the safety and efficacy of LI-guided ablation using standard (30 W) and high-power (50 W) in a preclinical model. Methods: RF lesions were created in explanted swine hearts (n = 6) to assess the feasibility of LI-guided ablation by targeting 10, 20, or 30 Ω (n = 20/group) drops. Subsequently, LI-guided ablation was evaluated in a chronic animal model (n = 8 Canines, 25–29 kg, 30/50 W). During the index procedure point-by-point intercaval line ablation and left inferior pulmonary vein (PV) isolation were performed. RF duration was at the operators’ discretion but discontinued early if a 15–30 Ω drop was achieved. Operators attempted to avoid LI drops of more than 40 Ω. At 1-month, durable conduction block was evaluated with electroanatomic mapping followed by necropsy and histopathology. Results: In explanted tissue, terminating ablation at 10, 20, or 30 Ω LI drops created statistically larger lesions (p <.05; 1.8 [1.6–2.4] mm, 3.3 [3.0–3.7] mm; 4.9 [4.3–5.5] mm). LI-guided high-power ablation in vivo significantly reduced RF duration per application compared to standard-power (p <.05; intercaval: 8.9 ± 5.2 vs. 18.1 ± 11.0 s, PV: 9.6 ± 5.4 vs. 23.2 ± 10.3 s). LI drops of 15–40 Ω were more readily achievable for high-power (90.1%, 318/353) than standard-power (71.7%, 243/339). All intercaval lines and PV isolations were durable (16/16) at 1-month. Necropsy revealed no major collateral injury to the pericardium, phrenic nerve, esophagus, or lungs. There was no pericardial effusion, stroke, tamponade, or PV stenosis. Vagal nerve injury was found in two 30 W animals after using 19.7 ± 13.9 and 19.5 ± 11.8 s RF applications. Conclusion: LI-guided ablation was found to be safe and efficacious in a chronic animal model. High-power ablation more readily achieved more than 15 Ω drops, reduced RF duration compared with standard-power, and had no major RF collateral injury.
KW - conduction block
KW - local impedance
KW - radiofrequency ablation
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U2 - 10.1111/jce.15135
DO - 10.1111/jce.15135
M3 - Article
C2 - 34223691
AN - SCOPUS:85110015442
SN - 1045-3873
VL - 32
SP - 2060
EP - 2068
JO - Journal of cardiovascular electrophysiology
JF - Journal of cardiovascular electrophysiology
IS - 8
ER -