Combined local impedance and contact force for radiofrequency ablation assessment

Kara Garrott, Jacob Laughner, Sarah Gutbrod, Alan Sugrue, Allan Shuros, Matt Sulkin, Omar Yasin, Jamie Bush, Nathan Pottinger, Jason Meyers, Suraj Kapa

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background: The combination of contact force (CF) and local impedance (LI) may improve tissue characterization and lesion prediction during radiofrequency (RF) ablation. Objective: The purpose of this study was to evaluate the utility of LI combined with CF in assessing RF ablation efficacy. Methods: An LI catheter with CF sensing was evaluated in swine (n = 11) and in vitro (n = 14). The relationship between LI and CF in different tissue types was evaluated in vivo. Discrete lesions were created in vitro and in vivo at a range of forces, powers, and durations. Finally, an intercaval line was created in 3 groups at 30 W: 30s, Δ20Ω, and Δ30Ω. In the Δ20Ω and Δ30Ω groups, the user ablated until a 20 or 30 Ω LI drop. In the 30s group, the user was blinded to LI. Results: In vivo, distinction in LI was found between the blood pool and the myocardium (blood pool: 122 ± 7.02 Ω; perpendicular contact: 220 ± 29 Ω; parallel contact: 207 ± 31 Ω). LI drop correlated with lesion depth both in vitro (R = 0.84) and in vivo (R = 0.79), informing sufficient lesion creation (LI drop >20 Ω) and warning of excessive heating (LI drop >65 Ω). When creating an intercaval line, the total RF time was significantly reduced when using LI guidance (6.4 ± 2 minutes in Δ20Ω and 8.1 ± 1 minutes in Δ30Ω) compared with a standard 30-second workflow (18 ± 7 minutes). Acute conduction block was achieved in all Δ30Ω and 30s lines. Conclusion: The addition of LI to CF provides feedback on both electrical and mechanical loads. This provides information on tissue type and catheter-tissue coupling; provides feedback on whether volumetric tissue heating is inadequate, sufficient, or excessive; and reduces ablation time.

Original languageEnglish (US)
Pages (from-to)1371-1380
Number of pages10
JournalHeart rhythm
Issue number8
StatePublished - Aug 2020


  • Ablation
  • Contact force
  • Electroanatomic mapping
  • Impedance
  • Radiofrequency

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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