Novel Measure of Local Impedance Predicts Catheter–Tissue Contact and Lesion Formation

Sulkin, Matthew S.; Laughner, Jacob I.; Hilbert, Sebastian; Kapa, Suraj; Kosiuk, Jędrzej; Younan, Paul; Romero, Iñaki; Shuros, Allan; Hamann, Jason J.; Hindricks, Gerhard; Bollmann, Andreas

doi:10.1161/circep.117.005831

Cited by 79 publications

(155 citation statements)

References 18 publications

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“…Albeit baseline LI is in general lower than baseline GI, impedance drop during RFC‐application is higher for LI than for GI. This finding is in line with initial experimental studies and early clinical data . We showed a correlation of ΔLI with baseline LI, albeit with a low correlation coefficient, which is most likely attributable to heterogenities of ventricular myocardial tissue.…”

Section: Discussionsupporting

confidence: 91%

“…Discrimination of healthy and scarred tissue using LI was initially demonstrated in acute and chronic models of myocardial infarction . More than two decades later, translation of experimental findings to early clinical experience using an ablation catheter incorporating LI measurements has recently been reported . Here, we demonstrate that LI can identify areas of scar in patients with VT.…”

Section: Discussionmentioning

confidence: 65%

“…Recently, a novel ablation catheter incorporating three mini‐electrodes in its tip measuring local impedance (LI) at the distal electrode of the catheter has been developed and introduced to clinical practice . Herein, we studied LI in comparison to GI during catheter ablation of ventricular tachycardia (VT) to assess its applicability as a feed‐back‐parameter of RFC‐ablation.…”

Section: Introductionmentioning

confidence: 99%

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Local impedance guides catheter ablation in patients with ventricular tachycardia

Münkler

Gunawardene

Jungen

et al. 2019

Cardiovasc electrophysiol

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Aims: Catheter contact and local tissue characteristics are relevant information for successful radiofrequency current (RFC)-ablation. Local impedance (LI) has been shown to reflect tissue characteristics and lesion formation during RFC-ablation.Using a novel ablation catheter incorporating three mini-electrodes, we investigated LI in relation to generator impedance (GI) in patients with ventricular tachycardia (VT) and its applicability as an indicator of effective RFC-ablation. Methods and Results: Baseline impedance, Δimpedance during ablation and drop rate (Δimpedance/time) were analyzed for 625 RFC-applications in 28 patients with recurrent VT undergoing RFC-ablation. LI was lower in scarred (87.0 Ω [79.0-95.0]) compared to healthy myocardium (97.5 Ω ([82.75-111.50]; P = .03) while GI did not differ between scarred and healthy myocardium. ΔLI was higher (18 Ω [9.4-26.0]) for VT-terminating as compared to non-terminating RFC-ablation (ΔLI 13 Ω [8.85-18.0]; P = .03), but did not differ for ΔGI between terminating vs nonterminating RFCablation. Correspondingly, LI drop rate was higher for RFC-ablation terminating the VT compared with RFC-ablation not terminating the VT (0.63 Ω/s [0.52-0.76] vs 0.32 Ω [0.20-0.58]; P = .008) while there was no difference for GI drop rate. ΔLI was higher in patients with nonischemic cardiomyopathy vs patients with ischemic cardiomyopathy (16 Ω [11.0-20.0] vs 11.0 Ω [7.85-17.00]; P = .003).Conclusion: Our findings suggest that LI is a sensitive parameter to guide RFCablation in patients with VT. LI indicates differences in tissue characteristics and generally is higher in patients with nonischemic cardiomyopathy. Hence, the etiology of the underlying cardiomyopathy needs to be considered when adopting LI for monitoring catheter ablation of VT. K E Y W O R D Scatheter ablation, electrical impedance, high-density mapping, radiofrequency, ventricular tachycardia ---

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

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Local impedance guides catheter ablation in patients with ventricular tachycardia

Münkler

Gunawardene

Jungen

et al. 2019

Cardiovasc electrophysiol

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“…However, it should be acknowledged that contact force is not without limitations and it entails a higher cost; contact force does not take into consideration tissue characteristics or catheter stability. A recent study found that local impedance had a superior fit to lesion dimension than models that incorporated force time integral [14]. Thus, it is worth exploring if other parameters could also be of value in determining a successful lesion.…”

Section: Pre-ablation Parameters and Transmural Lesionsmentioning

confidence: 99%

“…Intracardiac echocardiography has been used in some studies, but it was found unable to precisely delineate lesion dimensions [15]. Generator impedance drop has been shown to correlate poorly with lesion depth and even worse with lesion diameter [14]. Local impedance appears to be a reliable indicator of lesion formation [14] but was not available at the time of the study.…”

Section: Limitationsmentioning

confidence: 99%

Electrogram voltage and pacing threshold before ablation, measured by mini-electrodes, predict parameters indicative of transmural lesions in the human atrium

Lázaro

Barrio-López

Castellanos

et al. 2019

J Interv Card Electrophysiol

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Purpose An important attenuation of the atrial signal recorded with mini-electrodes (ME) embedded in an 8-mm tip was associated with a transmural radiofrequency lesion. Our aim was to assess if parameters obtained from ME or conventional bipoles before applications predict successful atrial lesions. Methods We prospectively included 33 consecutive patients undergoing cavotricuspid isthmus (CTI) ablation. Electrogram voltages and pacing thresholds were measured with ME and conventional bipoles before and after radiofrequency (RF) applications. The time before the loss of capture during applications was recorded. Lesions were considered successful, in accordance with preclinical data, if ME voltage decreased > 54%. Results Of 207 applications, 107 could be analyzed. During applications, voltages decreased more in the ME than in the conventional bipoles (66.8 ± 26.1% vs 37.5 ± 42.5%, P = 0.001). Likewise, pacing threshold increased significantly more using the ME (86.3 ± 22.9% ME, 52.6 ± 35.6% conventional, P = 0.001). ME pre-ablation voltages were significantly higher and pacing thresholds significantly lower in successful lesions (voltage 0.88 ± 0.71 vs 0.26 ± 0.18 mV, P = 0.0001; threshold 1.6 ± 1.7 vs 2.8 ± 3.0, P = 0.04). Neither of these parameters with conventional bipoles nor time to loss of capture showed differences. A ME voltage > 0.33 mV and a pacing threshold < 1.5 mA predicted a successful lesion with 0.78 and 0.6 sensitivity and 0.78 and 0.59 specificity. Conclusions Certain pre-ablation parameters derived from ME such as electrogram voltage and pacing threshold differ from those obtained by a conventional configuration and can predict a successful atrial lesion.

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Optimal local impedance drops for an effective radiofrequency ablation during cavo‐tricuspid isthmus ablation

Sasaki

Nakamura

Inoue

et al. 2020

Journal of Arrhythmia

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Novel Measure of Local Impedance Predicts Catheter–Tissue Contact and Lesion Formation

Abstract: LI recorded from miniature electrodes provides a valuable measure of catheter-tissue coupling, and ΔLI is predictive of lesion formation during radiofrequency ablation.

Cited by 79 publications

References 18 publications

Local impedance guides catheter ablation in patients with ventricular tachycardia

Local impedance guides catheter ablation in patients with ventricular tachycardia

Electrogram voltage and pacing threshold before ablation, measured by mini-electrodes, predict parameters indicative of transmural lesions in the human atrium

Optimal local impedance drops for an effective radiofrequency ablation during cavo‐tricuspid isthmus ablation

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