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Bahlke F, Wachter A, Erhard N, Englert F, Syväri J, Krafft H, Popa M, Abdiu E, Lennerz C, Telishevska M, Lengauer S, Reents T, Hessling G, Deisenhofer I, Bourier F. Radiofrequency ablation-Real-time visualization of lesions and their correlation with underlying parameters. Pacing Clin Electrophysiol 2024; 47:994-1003. [PMID: 38728067 DOI: 10.1111/pace.14992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/10/2024] [Accepted: 04/09/2024] [Indexed: 08/07/2024]
Abstract
BACKGROUND Lesion durability and transmurality are crucial for successful radiofrequency (RF) ablation. This study provides a model of real-time RF lesion visualization and insights into the role of underlying parameters, as local impedance (LI). METHODS A force-sensing, LI-sensing catheter was used for lesion creation in an ex vivo model involving cross-sections of porcine cardiac preparations. During 60 s of RF application, one measurement per second was performed regarding lesion size and available ablation parameters. In total, 1847 measurements from n = 36 lesions were performed. Power (20-50 W) and contact force (1-5 g, 10-15 g, 20-25 g) were systematically alternated. RESULTS Lesion formation was most prominent in the first seconds of RF application during which nonlinear lesion growth was observed (max. 1.08 mm/s for lesion depth and 2.71 mm/s for lesion diameter). Power levels determined the extent of lesion formation in the early phase. After 20 s, lesion size growth velocity approaches 0.1 mm/s at all power levels. LI changes were also highest in the first seconds (up to - 12 Ω/s) and decreased to less than - 0.1Ω/s after prolonged application. CONCLUSION Lesion formation in irrigated RF ablation is a nonlinear process. Final lesion size resulting from an RF application is mainly influenced by high rates of lesion growth in the first seconds of ablation. LI seems to be a good surrogate for differentiating changes in lesion formation.
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Affiliation(s)
- Fabian Bahlke
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Andreas Wachter
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Nico Erhard
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Florian Englert
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Jan Syväri
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Hannah Krafft
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Miruna Popa
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Edison Abdiu
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Carsten Lennerz
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Marta Telishevska
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Sarah Lengauer
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Tilko Reents
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Gabriele Hessling
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Isabel Deisenhofer
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
| | - Felix Bourier
- Department of Electrophysiology, German Heart Center Munich, Technical University Munich, Munich, Germany
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Iwakawa H, Takigawa M, Yamaguchi J, Martin CA, Goya M, Yamamoto T, Amemiya M, Ikenouchi T, Negishi M, Kawamura I, Goto K, Shigeta T, Nishimura T, Takamiya T, Tao S, Miyazaki S, Watanabe H, Sasano T. Superiority of the Combination of Input and Output Parameters to the Single Parameter for Lesion Size Estimation. Circ J 2023; 87:1757-1764. [PMID: 37899173 DOI: 10.1253/circj.cj-23-0574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
BACKGROUND For lesion size prediction, each input parameter, including ablation energy (AE), and output parameter, such as impedance, is individually used. We hypothesize that using both parameters simultaneously may be more optimal.Methods and Results: Radiofrequency applications at a range of power (30-50 W), contact force (10 g and 20 g), duration (10-60 s), and catheter orientation with normal saline (NS)- or half-normal saline (HNS)-irrigation were performed in excised porcine hearts. The correlations, with lesion size of AE, absolute impedance drop (∆Imp-drop), relative impedance drop (%Imp-drop), and AE*%Imp-drop were examined. Lesion size was analyzed in 283 of 288 lesions (NS-irrigation, n=142; HNS-irrigation, n=141) without steam pops. AE*%Imp-drop consistently showed the strongest correlations with lesion maximum depth (NS-irrigation, ρ=0.91; HNS-irrigation, ρ=0.94), surface area (NS-irrigation, ρ=0.87; HNS-irrigation, ρ=0.86), and volume (NS-irrigation, ρ=0.94; HNS-irrigation, ρ=0.94) compared with the other parameters. Moreover, compared with AE alone, AE*%Imp-drop significantly improved the strength of correlation with lesion maximum depth (AE vs. AE*%Imp-drop, ρ=0.83 vs. 0.91, P<0.01), surface area (ρ=0.73 vs. 0.87, P<0.01), and volume (ρ=0.84 vs. 0.94, P<0.01) with NS-irrigation. This tendency was also observed with HNS-irrigation. Parallel catheter orientation showed a better correlation with lesion depth and volume using ∆Imp-drop, %Imp-drop, and AE*%Imp-drop than perpendicular orientation. CONCLUSIONS The combination of input and output parameters is more optimal than each single parameter for lesion prediction.
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Affiliation(s)
- Hidehiro Iwakawa
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
- Department of Cardiovascular Medicine, Akita University Graduate School of Medicine
| | - Masateru Takigawa
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Junji Yamaguchi
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | | | - Masahiko Goya
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Tasuku Yamamoto
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Miki Amemiya
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Takashi Ikenouchi
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Miho Negishi
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Iwanari Kawamura
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Kentaro Goto
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Takatoshi Shigeta
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Takuro Nishimura
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Tomomasa Takamiya
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Susumu Tao
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Shinsuke Miyazaki
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - Hiroyuki Watanabe
- Department of Cardiovascular Medicine, Akita University Graduate School of Medicine
| | - Tetsuo Sasano
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
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Bahlke F, Wachter A, Erhard N, Englert F, Krafft H, Popa M, Risse E, Kottmaier M, Telishevska M, Lengauer S, Lennerz C, Reents T, Hessling G, Deisenhofer I, Bourier F. The influence of electrode-tissue-coverage on RF lesion formation and local impedance: Insights from an ex vivo model. Pacing Clin Electrophysiol 2023; 46:1170-1181. [PMID: 37616376 DOI: 10.1111/pace.14807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/16/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023]
Abstract
BACKGROUND The influence of power, duration and contact force (CF) on radiofrequency (RF) lesion formation is well known, whereas data on local impedance (LI) and electrode-tissue-coverage (ETC) is scarce. The objective was to investigate their effect on lesion formation in an ex vivo model. METHODS AND RESULTS An ex vivo model was developed utilizing cross-sections of porcine heart preparations and a force-sensing, LI-measuring catheter. N = 72 lesion were created systematically varying ETC (minor/full), CF (1-5 g, 10-15 g, 20-25 g) and power (20 W, 30 W, 40 W, 50 W). In minor ETC, the distal tip of the catheter was in electric contact with the tissue, in full ETC the whole catheter tip was embedded within the tissue. Lesion size and all parameters were measured once per second (n = 3320). LI correlated strongly with lesion depth (r = -0.742 for ΔLI; r = 0.781 for %LI-drop). Lesions in full ETC were significantly wider and deeper compared to minor ETC (p < .001) and steam pops were more likely. Baseline LI, ΔLI, and %LI-drop were significantly higher in full ETC (p < .001). In lesions resulting in steam pops, baseline LI, and ΔLI were significantly higher. The influence of CF on lesion size was higher in minor ETC than in full ETC. CONCLUSIONS ETC is a main determinant of lesion size and occurrence of steam pops. Baseline LI and LI-drop are useful surrogate parameters for real-time assessment of ETC and ΔLI correlates strongly with lesion size.
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Affiliation(s)
- Fabian Bahlke
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Andreas Wachter
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Nico Erhard
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Florian Englert
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Hannah Krafft
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Miruna Popa
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Elena Risse
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Marc Kottmaier
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Marta Telishevska
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Sarah Lengauer
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Carsten Lennerz
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Tilko Reents
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Gabriele Hessling
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Isabel Deisenhofer
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
| | - Felix Bourier
- Department of Electrophysiology, German Heart Center Munich, Technical University of Munich (TUM), Munich, Germany
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Takigawa M, Yamamoto T, Amemiya M, Martin CA, Ikenouchi T, Yamaguchi J, Negishi M, Goto K, Shigeta T, Nishimura T, Tao S, Miyazaki S, Goya M, Sasano T. Impact of baseline pool impedance on lesion metrics and steam pops in catheter ablation. J Cardiovasc Electrophysiol 2023; 34:1671-1680. [PMID: 37337433 DOI: 10.1111/jce.15964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/19/2023] [Accepted: 05/29/2023] [Indexed: 06/21/2023]
Abstract
INTRODUCTION Little is known about the impact of blood-pool local impedance (LI) on lesion characteristics and the incidence of steam pops. METHODS Radiofrequency applications at a range of powers (30, 40, and 50 W), contact forces (CF) (5, 15, and 25 g), and durations (15, 30, 45, and 120 s) using perpendicular/parallel catheter orientation were performed in 40 excised porcine preparations, using a catheter capable of monitoring LI (StablePoint©, Boston Scientific). To simulate the variability in blood-pool impedance, the saline-pool LI was modulated by calibrating saline concentrations. Lesion characteristics were compared under three values of saline-pool LI: 120, 160, and 200 Ω. RESULTS Of 648 lesions created, steam pops occurred in 175 (27.0%). When power, CF, time, and catheter orientation were adjusted, ablation at a saline-pool impedance of 160 or 200 Ω more than doubled the risk of steam pops compared with a saline-pool impedance of 120 Ω (Odds ratio = 2.31; p = .0002). Lesions in a saline-pool impedance of 120 Ω were significantly larger in surface area (50 [38-62], 45 [34-56], and 41 [34-60] mm2 for 120, 160, and 200 Ω, p < .05), but shallower in depth (4.0 [3-5], 4.4 [3.2-5.3], and 4.5 [3.8-5.5] mmfor 120, 160, and 200 Ω, respectively, p < .05) compared with the other two settings. The correlation between the absolute LI-drop and lesion size weakened as the saline-pool LI became higher (e.g., 120 Ω group (r2 = .30, r2 = .18, and r2 = .16, respectively for 120, 160, and 200 Ω), but the usage of %LI-drop (= absolute LI-drop/initial LI) instead of absolute LI-drop may minimize this effect. CONCLUSIONS In an experimental model, baseline saline-pool impedance significantly affects the lesion metrics and the risk of steam pops.
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Affiliation(s)
- Masateru Takigawa
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tasuku Yamamoto
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Miki Amemiya
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Claire A Martin
- Royal Papworth Hospital, Cambridge University, Cambridge, UK
| | - Takashi Ikenouchi
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junji Yamaguchi
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Miho Negishi
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kentaro Goto
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takatoshi Shigeta
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takuro Nishimura
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Susumu Tao
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinsuke Miyazaki
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masahiko Goya
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuo Sasano
- Department of Cardiovascular Medicine, Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
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Solimene F, Schillaci V, Stabile G, Shopova G, Arestia A, Salito A, Maddaluno F, Malacrida M, Strisciuglio T. Prospective evaluation of local impedance drop to guide left atrial posterior wall ablation with high power. J Interv Card Electrophysiol 2022; 65:675-684. [PMID: 35906492 DOI: 10.1007/s10840-022-01317-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/20/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND Local impedance (LI) drop predicts acute conduction block during pulmonary vein isolation (PVI). Whether the LI drop predicts also the achievement of left atrial posterior wall isolation (LAPWI) in persistent atrial fibrillation (PersAF) patients is unknown. We evaluated the efficacy and the safety of LI drop-guided LAPW ablation by using high power (50 watts) and investigated the impact of ablation parameters on the LI drop. METHODS We included consecutive PersAF patients underwent PVI and both roof line and floor line completion to achieve LAPWI with a novel contact force (CF)- and LI-featured catheter (IntellaNAV Stablepoint™). For each radiofrequency (RF) application, we targeted a LI drop of 25 ohms. RESULTS Out of 30 patients, first-pass floor line block was achieved in 26 (87%) and first-pass roof line block in 17 (57%), resulting in first-pass LAPWI in 14 patients (47%). After touch-up ablations, LAPWI was achieved in 28 patients (93%) with endocardial ablation only. No procedural nor 1-month complications occurred. Overall, 877 RF applications were delivered: 787 ablation tags (89%) were associated with acute conduction block, while 90 (11%) were located at sites of acute gaps in either the roof or floor line. LI drop values were greater at segments with acute block than those with gaps (p < 0.001). At multivariable analysis, only LI drop and RF time remained independently associated with the acute block (p < 0.001; p = 0.001). CONCLUSIONS LI drop-guided LAPWI at a fixed power of 50 W was effective and did not lead to complications. LI drop was the most important predictor of acute conduction block.
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Affiliation(s)
| | | | - Giuseppe Stabile
- Clinica Montevergine, Mercogliano, Avellino, Italy.,Anthea Hospital, Bari, Italy
| | | | | | | | | | | | - Teresa Strisciuglio
- Clinica Montevergine, Mercogliano, Avellino, Italy.,University of Naples Federico II, Naples, Italy
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Limitations of Baseline Impedance, Impedance Drop and Current for Radiofrequency Catheter Ablation Monitoring: Insights from In silico Modeling. J Cardiovasc Dev Dis 2022; 9:jcdd9100336. [PMID: 36286288 PMCID: PMC9604830 DOI: 10.3390/jcdd9100336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/06/2022] Open
Abstract
Background: Baseline impedance, radiofrequency current, and impedance drop during radiofrequency catheter ablation are thought to predict effective lesion formation. However, quantifying the contributions of local versus remote impedances provides insights into the limitations of indices using those parameters. Methods: An in silico model of left atrial radiofrequency catheter ablation was used based on human thoracic measurements and solved for (1) initial impedance (Z), (2) percentage of radiofrequency power delivered to the myocardium and blood (3) total radiofrequency current, (4) impedance drop during heating, and (5) lesion size after a 25 W−30 s ablation. Remote impedance was modeled by varying the mixing ratio between skeletal muscle and fat. Local impedance was modeled by varying insertion depth of the electrode (ID). Results: Increasing the remote impedance led to increased baseline impedance, lower system current delivery, and reduced lesion size. For ID = 0.5 mm, Z ranged from 115 to 132 Ω when fat percentage varied from 20 to 80%, resulting in a decrease in the RF current from 472 to 347 mA and a slight decrease in lesion size from 5.6 to 5.1 mm in depth, and from 9.2 to 8.0 mm in maximum width. In contrast, increasing the local impedance led to lower system current but larger lesions. For a 50% fat−muscle mixture, Z ranged from 118 to 138 Ω when ID varied from 0.3 to 1.9 mm, resulting in a decrease in the RF current from 463 to 443 mA and an increase in lesion size, from 5.2 up to 7.5 mm in depth, and from 8.4 up to 11.6 mm in maximum width. In cases of nearly identical Z but different contributions of local and remote impedance, markedly different lesions sizes were observed despite only small differences in RF current. Impedance drop better predicted lesion size (R2 > 0.93) than RF current (R2 < 0.1). Conclusions: Identical baseline impedances and observed RF currents can lead to markedly different lesion sizes with different relative contributions of local and remote impedances to the electrical circuit. These results provide mechanistic insights into the advantage of measuring local impedance and identifies potential limitations of indices incorporating baseline impedance or current to predict lesion quality.
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Requirement of larger local impedance reduction for successful lesion formation at carinal area during pulmonary vein isolation. J Interv Card Electrophysiol 2022; 65:509-518. [PMID: 35794439 DOI: 10.1007/s10840-022-01282-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/15/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE Local impedance (LI) measurement from an ablation catheter is useful in predicting lesion size and acute success of pulmonary vein isolation (PVI). The LI variation can be described by absolute LI drop (ΔLID) or ΔLID/initial LI (%LID). We evaluated the utility of these parameters in predicting acute lesion durability during PVI using a novel catheter capable of measuring both LI and contact force (CF). METHODS PVI with a targeted CF, power, and duration was performed in 23 consecutive patients with paroxysmal atrial fibrillation. LI was blinded to operators during ablation. Parameters for each RF application were collected and compared for acute successful lesions and gaps. RESULTS A total of 1633 RF applications including 97 (5.9%) gap lesions were analyzed. Successful lesions were more frequently observed at non-carinal sites and those with higher contact force, FTI, initial LI, and larger variation of LI and generator impedance (GI). Multivariate analysis demonstrated that absolute GI drop (ΔGID) [OR 1.09 (1.04-1.15), p < 0.001], ΔLID [1.12 (1.09-1.16), p < 0.001], ΔGID/initial GI (%GID) [OR 1.04 (1.01-1.07), p = 0.01], and %LID [OR 1.15 (1.12-1.28), p < 0.001] were significantly associated with successful lesions, and carinal site [OR 0.15(0.09-0.24), p < 0.001] was significantly related to gaps. Both ΔLID and %LID equally predicted the acute durability of lesions during PVI. ΔLID ≥ 24Ω and %LID ≥ 15% at the carina, and ΔLID ≥ 21Ω and %LID ≥ 14% at non-carinal sites significantly predicted acute successful lesions with negative predictive values of 93-99%. CONCLUSIONS Both ΔLID and %LID were equally useful in predicting acute successful lesions during PVI. Larger cut-off values should be applied to carinal sites.
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Comparison of two catheters measuring local impedance: local impedance variation vs lesion characteristics and steam pops. J Interv Card Electrophysiol 2022; 65:419-428. [PMID: 35438394 DOI: 10.1007/s10840-022-01214-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/31/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE The size of the distal electrode and the method of measuring local impedance (LI) are different between the IntellaNav MiFi-OI™ (MiFi-OI) and IntellaNav STABLE POINT™ (SP) catheters. We investigated the impact of these differences on LI, efficacy, and safety of radiofrequency (RF) applications. METHODS RF applications at a range of powers (30 W, 40 W, and 50 W), contact forces (10 g and 20 g), and durations (10-120 s) were performed in excised porcine hearts (N = 48). LI variation was defined by δLI-drop (= initial LI - post-RF LI) and %LI-drop (= δLI-drop/initial LI) × 100, and the relationship between lesion characteristics and LI variation was compared. RESULTS A total of 576 lesions were examined. Although absolute δLI-drop during RF applications was significantly larger for the SP than MiFi-OI catheter (47[31-65]ohm for SP vs 37[24-51]ohm for MiFi-OI, p < 0.0001), %LI-drop was similar (23.3 [15.5-30.6]% in SP vs 24.9[17.3-32.5]% in MiFi-OI, p = 0.10). Although lesions produced by both catheters were similarly correlated with LI variation, the SP catheter produced generally larger lesions (depth; 5.0 [3.7-6.1]mm vs 4.7 [3.3-6.0]mm, p = 0.06; surface areas, 46.9 [36.8-58.8]mm2 vs 44.7 [34.3-55.5]mm2, p = 0.02; volume, 321 [165-533]mm3 vs 265[141-471]mm3, p = 0.02). Steam pops were similarly observed with both catheters. In both catheters, %LI-drop was superior to δLI-drop in correlation to lesion size (p < 0.0001) and in predicting steam pops (p < 0.01). CONCLUSIONS Although no difference in safety profile is observed between MiFi-OI and SP catheters, the SP catheter produces larger lesions. %LI-drop is superior to δLI-drop in correlation to lesion size and in predicting steam pops as well as in normalizing the difference between catheters.
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9
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Masnok K, Watanabe N. Catheter contact area strongly correlates with lesion area in radiofrequency cardiac ablation: an ex vivo porcine heart study. J Interv Card Electrophysiol 2022; 63:561-572. [PMID: 34499311 PMCID: PMC9151538 DOI: 10.1007/s10840-021-01054-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/18/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE Our previous study confirmed that not only force but also the catheter contact angle substantially impacted the contact area and its morphology. Therefore, in this study, we aimed to further investigate the relationship between the catheter contact area and the dimensions of the ablation lesion area as a function of catheter contact angle and force in radiofrequency catheter ablation. METHODS The radiofrequency catheter ablation test was performed for 5 contact angles and 8 contact forces at a fixed ablation time of 30 s. The initial impedance was 92.5 ± 2.5 Ω, the temperature during ablation was 30 °C, and the power was 30 W. The irrigation rate during ablation was set to 17 mL/min. Each experiment was repeated 6 times. RESULTS The catheter contact area showed a strong correlation with the ablation lesion area (r = 0.8507). When the contact area was increased, the lesion area also increased linearly in a monotonic manner. The relationships between catheter contact force and ablation lesion area and between catheter contact force and ablation lesion depth are logarithmic functions in which increased contact force was associated with increased lesion area and depth. The catheter contact angle is also an important determinant of the lesion area. The lesion area progressively increased when the contact angle was decreased. In contrast, the lesion depth progressively increased when the contact angle was increased. CONCLUSIONS The catheter contact area was strongly correlated with the ablation lesion area. Additionally, catheter contact force and contact angle significantly impacted the dimensions of the lesion in radiofrequency catheter ablation procedures.
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Affiliation(s)
- Kriengsak Masnok
- Biofluid Science and Engineering Laboratory, Functional Control Systems, Graduate School of Engineering and Science, Shibaura Institute of Technology, Room-102, 6th Building, Omiya-Campus, 307 Fukasaku, Minuma-Ku, Saitama-City, Saitama, 337-8570, Japan
| | - Nobuo Watanabe
- Biofluid Science and Engineering Laboratory, Functional Control Systems, Graduate School of Engineering and Science, Shibaura Institute of Technology, Room-102, 6th Building, Omiya-Campus, 307 Fukasaku, Minuma-Ku, Saitama-City, Saitama, 337-8570, Japan.
- Department of Bio-Science and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan.
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Nussinovitch U, Wang P, Narayan S, Viswanathan M, Badhwar N, Zheng L, Sauer WH, Nguyen DT. Perpendicular Catheter Orientation During Papillary Muscle Ablation Results in Larger, Deeper Lesions. J Cardiovasc Electrophysiol 2022; 33:690-695. [PMID: 35133050 DOI: 10.1111/jce.15408] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/29/2021] [Accepted: 01/01/2022] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Ablation of papillary muscles (PM) for refractory ventricular arrhythmias can often be challenging. The catheter approach and orientation during ablation may affect optimal radiofrequency (RF) delivery. Yet, no previous study investigated the association between catheter orientation and PM lesion size. We evaluated ablation lesion characteristics with various catheter orientations relative to the PM tissue during open irrigated ablation, using a standardized, experimental setting. METHODS Viable bovine PM was positioned on a load cell in a circulating saline bath. RF ablation was performed over PM tissue at 50W, with the open irrigated catheter positioned either perpendicular or parallel to the PM surface. Applied force was 10 grams. Ablation lesions were sectioned and underwent quantitative morphometric analysis. RESULTS A catheter position oriented directly perpendicular to the PM tissue resulted in the largest ablation lesion volumes and depths compared to ablation with the catheter parallel to PM tissue (75.26±8.40 mm3 vs. 34.04±2.91 mm3 , p<0.001) and (3.33±0.18 mm vs. 2.24±0.10 mm, p<0.001), respectively. There were no significant differences in initial impedance, peak voltage, peak current, or overall decrease in impedance among groups. Parallel catheter orientation resulted in higher peak temperature (41.33±0.28°C vs. 40.28±0.24°C, p=0.003), yet, there were no steam pops in either group. CONCLUSION For PM ablation, catheter orientation perpendicular to the PM tissue achieves more effective and larger ablation lesions, with greater lesion depth. This may have implications for the chosen ventricular access approach, the type of catheter used, consideration for remote navigation, and steerable sheaths. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Udi Nussinovitch
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Paul Wang
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Sanjiv Narayan
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Mohan Viswanathan
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Nitish Badhwar
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Lijun Zheng
- Section of Cardiac Electrophysiology, Division of Cardiology, University of Colorado, Aurora, Colorado
| | - William H Sauer
- Section of Cardiac Electrophysiology, Division of Cardiology, Brigham and Women's Hospital, Boston, MA
| | - Duy T Nguyen
- Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
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11
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Sasaki T, Nakamura K, Minami K, Take Y, Nakatani Y, Miki Y, Goto K, Kaseno K, Yamashita E, Koyama K, Naito S. Local impedance measurements during contact force‐guided cavotricuspid isthmus ablation for predicting an effective radiofrequency ablation. J Arrhythm 2022; 38:245-252. [PMID: 35387143 PMCID: PMC8977576 DOI: 10.1002/joa3.12680] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/05/2022] [Accepted: 01/16/2022] [Indexed: 01/13/2023] Open
Abstract
Background An ablation catheter capable of contact force (CF) and local impedance (LI) monitoring (IntellaNav StablePoint, Boston Scientific) has been recently launched. We evaluated the relationship between the CF and LI values during radiofrequency catheter ablation (RFCA) along the cavotricuspid isthmus (CTI). Methods Fifty consecutive subjects who underwent a CTI‐RFCA using IntellaNav StablePoint catheters were retrospectively studied. The initial CF and LI at the start of the RF applications and mean CF and minimum LI during the RF applications were measured. The absolute and percentage LI drops were calculated as the difference between the initial and minimum LIs and 100 × absolute LI drop/initial LI, respectively. Results We analyzed 602 first‐pass RF applications. A weak correlation was observed between the initial CF and LI (r = 0.13) and between the mean CF and LI drops (r = 0.22). The initial LI and absolute and percentage LI drops were greater at effective ablation sites than ineffective ablation sites (median, 151 vs. 138 Ω, 22 vs. 14 Ω, and 14.4% vs. 9.9%; p < .001), but the initial and mean CF did not differ. At optimal cutoffs of 21 Ω and 10.8% for the absolute and percentage LI drops according to the receiver‐operating characteristic analysis, the sensitivity, and specificity for predicting an effective ablation were 57.4% and 88.9% and 80.0%, and 61.1%, respectively. Conclusions The effective sites during the CF‐guided CTI‐RFCA had greater initial LI and LI drops than the ineffective sites. Absolute and percentage LI drops of 21 Ω and 10.8% may be appropriate targets for an effective ablation.
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Affiliation(s)
- Takehito Sasaki
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Kohki Nakamura
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Kentaro Minami
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Yutaka Take
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Yosuke Nakatani
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Yuko Miki
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Koji Goto
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Kenichi Kaseno
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Eiji Yamashita
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Keiko Koyama
- Division of Radiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
| | - Shigeto Naito
- Division of Cardiology Gunma Prefectural Cardiovascular Center Maebashi City Japan
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12
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Lozano Granero C, Franco E, Matía Francés R, Hernández-Madrid A, Sánchez-Pérez I, Zamorano Gómez JL, Moreno J. Impact of power and contact force on index-guided radiofrequency lesions in an ex vivo porcine heart model. J Interv Card Electrophysiol 2022; 63:687-697. [PMID: 34997886 DOI: 10.1007/s10840-021-01110-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 12/27/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE Lesion size index (LSI) and ablation index (AI) are markers of lesion quality that incorporate power, contact force (CF) and time in a weighted formula to estimate lesion size. Although accurate predicting lesion depth in vitro, their precision in lesion size estimation has not been well established for certain power and CF settings. We conducted an experimental ex vivo study to analyse the effect of power and CF in size and morphology of ablation lesions in a porcine heart model. METHODS Twenty-four sets of 10 perpendicular epicardial radiofrequency applications were performed with two commercially available catheters (TactiCath, Sensor Enabled; and SmartTouch) on porcine left ventricle submerged in 37 °C saline, combining different power (25, 30, 35, 40, 50 and 60 W) and CF (10 and 20 g) settings, and aiming at a lower (LSI/AI of 5/400) or higher (LSI/AI of 6/550) index. After each application, lesions were cross-sectioned and measured. RESULTS Four hundred eighty lesions were performed. For a given target index and CF, significant differences in lesion volume and depth with different power were observed with both catheters, generally with smaller lesions using higher power. Lesions performed with CF of 10 g were particularly smaller with TactiCath compared to SmartTouch; lesions with CF of 20 g aiming a low LSI/AI were, however, bigger; lesions with CF of 20 g aiming a high LSI/AI were similar. In general, high-power lesions were wider and shallower than low-power lesions, especially with SmartTouch. CONCLUSION Size and morphology of index-guided radiofrequency lesions varied significantly with different power and CF settings.
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Affiliation(s)
- Cristina Lozano Granero
- Cardiology Department, Arrhythmia Unit, University Hospital Ramón Y Cajal, M-607, km 9100, 28034, Madrid, Spain.
| | - Eduardo Franco
- Cardiology Department, Arrhythmia Unit, University Hospital Ramón Y Cajal, M-607, km 9100, 28034, Madrid, Spain
| | - Roberto Matía Francés
- Cardiology Department, Arrhythmia Unit, University Hospital Ramón Y Cajal, M-607, km 9100, 28034, Madrid, Spain
| | - Antonio Hernández-Madrid
- Cardiology Department, Arrhythmia Unit, University Hospital Ramón Y Cajal, M-607, km 9100, 28034, Madrid, Spain
| | - Inmaculada Sánchez-Pérez
- Paediatric Cardiology Department, Arrhythmia Unit, University Hospital Ramón Y Cajal, M-607, km 9100, 28034, Madrid, Spain
| | | | - Javier Moreno
- Cardiology Department, Arrhythmia Unit, University Hospital Ramón Y Cajal, M-607, km 9100, 28034, Madrid, Spain
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13
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Stevenson WG, Sapp JL. Newer Methods for VT Ablation and When to Use Them. Can J Cardiol 2021; 38:502-514. [PMID: 34942300 DOI: 10.1016/j.cjca.2021.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 12/03/2021] [Accepted: 12/11/2021] [Indexed: 02/07/2023] Open
Abstract
Radiofrequency (RF) catheter ablation has long been an important therapy for ventricular tachycardia and frequent symptomatic premature ventricular beats and nonsustained arrhythmias when antiarrhythmic drugs fail to suppress the arrhythmias. It is increasingly used in preference to antiarrhythmic drugs, sparing the patient drug adverse effects. Ablation success varies with the underlying heart disease and type of arrhythmia, being very effective for patients without structural heart disease, less in structural heart disease. Failure occurs when a target for ablation cannot be identified, or ablation lesions fail to reach and abolish the arrhythmia substrate that may be extensive, intramural or subepicardial in location. Approaches to improving ablation lesion creation are modifications to RF ablation and emerging investigational techniques. Easily implemented modifications to RF methods include manipulating the size and location of the cutaneous dispersive electrode, increasing RF delivery duration, and use of lower tonicity catheter irrigation (usually 0.45% saline). When catheters can be placed on either side of culprit substrate RF can be delivered in a bipolar or simultaneous unipolar configuration that can be successful. Catheters with extendable/retractable irrigated needles for RF delivery are under investigation in clinical trials. Cryoablation is potentially useful in specific situations when maintaining contact is difficult. Transvascular ethanol ablation and stereotactic radioablation have both shown promise for arrhythmias that fail other ablation strategies. Although substantial clinical progress has been achieved, further improvement is clearly needed. With ability to increase ablation lesion size, continued careful evaluation of safety, which has been excellent for standard RF ablation, remains important.
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Affiliation(s)
- William G Stevenson
- The Cardiovascular Division, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee; The Heart Rhythm Service, Department of Medicine, Division of Cardiology, QEII Health Sciences Centre, Halifax, Nova Scotia, Canada.
| | - John L Sapp
- The Cardiovascular Division, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee; The Heart Rhythm Service, Department of Medicine, Division of Cardiology, QEII Health Sciences Centre, Halifax, Nova Scotia, Canada
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14
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Kawano D, Mori H, Kato R, Tsutsui K, Ikeda Y, Sumitomo N, Fukaya H, Iwagana S, Nakano S, Muramatsu T, Matsumoto K. The optimal ablation setting for a local impedance guided catheter in an in vitro experimental model. J Cardiovasc Electrophysiol 2021; 32:2069-2076. [PMID: 34185348 DOI: 10.1111/jce.15136] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 05/20/2021] [Accepted: 06/07/2021] [Indexed: 01/09/2023]
Abstract
BACKGROUND The local impedance (LI) reflects the electrical catheter-tissue coupling and correlates with the local tissue temperature. However, there have been few clinical studies showing the recommended method for LI monitoring catheters. This study aimed to investigate the optimal ablation setting for this catheter in an in vitro experimental model. METHODS LI monitoring catheters were used in an excised swine heart experimental model. The tissue contact force (CF) was directly monitored from an external weight scale. Radiofrequency ablation was performed with a combination of various energy power settings (30, 40, and 50 W), and various CFs (10, 30, and 50 g) for 60 s. The correlation between the LI-related indexes, power, and CF with the lesion formation was statistically analyzed. RESULTS A positive correlation between the LI or lesion formation and CF was observed under all powers. Although the LI drop always correlated with the maximum lesion depth, lesion diameter, and lesion volume, the coefficient of the correlation value was lower under a high CF (lesion depth, diameter, and volume; 10 g, r = 0.8064, r = 0.8389, r = 0.8477; 30 g, r = 0.7590, r = 0.8063, r = 0.8060; 50 g r = 0.5555, r = 0.5701, and r = 0.5678, respectively). Steam pops occurred only under a 50 W ablation and the LI drop cutoff value for steam pops was 46 Ω. CONCLUSION The same LI drop did not always lead to the same lesion size when the CF differed. Monitoring the LI and not exceeding 46 Ω would be useful for a safe ablation.
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Affiliation(s)
- Daisuke Kawano
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Hitoshi Mori
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan.,Department of Pediatric Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Ritsushi Kato
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Kenta Tsutsui
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Yoshifumi Ikeda
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Naokata Sumitomo
- Department of Pediatric Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Hidehira Fukaya
- Department of Cardiovascular Medicine, Kitasato University School of Medicine, Tokyo, Japan
| | - Shiro Iwagana
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Shintaro Nakano
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Toshihiro Muramatsu
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Kazuo Matsumoto
- Department of Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
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15
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Takigawa M, Goya M, Iwakawa H, Martin CA, Anzai T, Takahashi K, Kamata T, Matsumura Y, Amemiya M, Yamamoto T, Hirao T, Sekigawa M, Shirai Y, Tao S, Takahashi Y, Sasano T. Impact of a formula combining local impedance and conventional parameters on lesion size prediction. J Interv Card Electrophysiol 2021; 63:389-398. [PMID: 34156611 DOI: 10.1007/s10840-021-01013-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/23/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Although ablation energy (AE) and force-time integral (FTI) are well-known active predictors of lesion characteristics, these parameters do not reflect passive tissue reactions during ablation, which may instead be represented by drops in local impedance (LI). This study aimed to investigate if additional LI data improves predicting lesion characteristics and steam pops. METHODS RF applications at a range of powers (30 W, 40 W, and 50 W), contact forces (8 g, 15 g, 25 g, and 35 g), and durations (10-180 s) using perpendicular/parallel catheter orientations were performed in excised porcine hearts (N = 30). The correlation between AE, FTI, and lesion characteristics was examined, and the impact of LI (%LI drop (%LID) defined by the ΔLI divided by the initial LI) was additionally assessed. RESULTS Three hundred seventy-five lesions without steam pops were examined. Ablation energy (W × s) and FTI (g × s) showed a positive correlation with lesion depth (ρ = 0.824:P < 0.0001 and ρ = 0.708:P < 0.0001), surface area (ρ = 0.507:P < 0.0001 and ρ = 0.562:P < 0.0001), and volume (ρ = 0.807:P < 0.0001 and ρ = 0.685:P < 0.0001). %LID also showed a positive correlation individually with lesion depth (ρ = 0.643:P < 0.0001), surface area (ρ = 0.547:P < 0.0001), and volume (ρ = 0.733:P < 0.0001). However, the combined indices of AE × %LID (AE multiplied by %LID) and FTI × %LID (FTI multiplied by %LID) provided significantly stronger correlation with lesion depth (ρ = 0.834:P < 0.0001 and ρ = 0.809:P < 0.0001), surface area (ρ = 0.529:P < 0.0001 and ρ = 0.656:P < 0.0001), and volume (ρ = 0.864:P < 0.0001 and ρ = 0.838:P < 0.0001). This tendency was observed regardless of the catheter placement (parallel/perpendicular). AE (P = 0.02) and %LID (P = 0.002) independently remained as significant predictors to predict steam pops (N = 27). However, the AE × %LID did not increase the predictive power of steam pops compared to the AE alone. CONCLUSION LI, when combined with conventional parameters (AE and FTI), may provide stronger correlation with lesion characteristics.
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Affiliation(s)
- Masateru Takigawa
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan.
- Department of Advanced Arrhythmia Research, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Masahiko Goya
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Hidehiro Iwakawa
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
- Department of Cardiovascular Medicine, Graduate School of Medicine, Akita University, Akita, Japan
| | | | - Tatsuhiko Anzai
- Department of Biostatistics M&D Data Science Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kunihiko Takahashi
- Department of Biostatistics M&D Data Science Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tatsuaki Kamata
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Yu Matsumura
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Miki Amemiya
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Tasuku Yamamoto
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Tatsuhiko Hirao
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Masahiro Sekigawa
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Yasuhiro Shirai
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Susumu Tao
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Yoshihide Takahashi
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
- Department of Advanced Arrhythmia Research, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuo Sasano
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
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