Nonhomogeneous force application during typical flutter ablation explains local difficulties in lesion creation

Introduction – The current scientific literature suggests similar or even better catheter contact on caval regions of the cavo-tricuspid isthmus (CTI) compared to the more medial or annular part. Yet CTI ablation can be challenging owing to instability at the inferior vena cava (IVC) edge. No study specifically addressed the issue of catheter-tissue contact on caval/mid/annular regions of the CTI. Methods – Twenty-seven patients (22 men, 67±12 years) underwent typical atrial flutter ablation with a contact force (CF) sensing catheter (Tacticath 75, Abott) and were prospectively included. Operators aimed at optimizing CF for all RF pulses. The product of CF, time (force-time integral; FTI) and delivered power (FTPI) has been proposed as an estimate of lesion size. In a subset of 8 consecutive pts, electrograms (EGM) of all RF lesions were analyzed. Annular CTI was defined as sites showing both atrial and ventricular near-field bipolar EGM. Mid CTI sites had only atrial near field bipolar EGM on both distal and proximal dipoles (or distal only in case of superior-to-inferior approach). Caval sites had near-field bipolar EGM only in distal dipole, while the proximal one was inferiorly located. Results – Complete persistent (at 30 min) CTI block was obtained in all patients. A steerable sheath was used in 12 pts (44%). Procedure duration was 93±30 min, RF delivery time 10±6 min, fluoroscopy time 14±8 min. Mean CF was 15.8±5.9 g. CF was significantly lower (11.1±9.7 g) at the caval CTI than at mid CTI (19.9±11.8 g) and annular CTI (20±12.2 g; p=0.001). CF and FTI were higher during sinus rhythm than during Fl (23.2±15.3 vs 18.5±15.4 g, p=0.04 and 677±432 vs 532±357 gs, p=0.03). Use of a sheath improved mean CF (24.4±12.5 vs 18.4±14.9 g, p=0.01) but this was not significant at caval sites (17.5±11.4 vs 12.6±10.7 g, p=0.31). Conclusion – Applied forces are significantly lower at the IVC edge during CTI ablation. This supports the use of a steerable sheath in challenging cases.

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Determining inferior vena cava-tricuspid isthmus block after typical atrial flutter ablation

Heart Rhythm ◽

10.1016/j.hrthm.2004.12.008 ◽

2005 ◽

Vol 2 (3) ◽

pp. 328-332 ◽

Cited By ~ 10

Author(s):

Francisco G. Cosío ◽

Paula Awamleh ◽

Agustín Pastor ◽

Ambrosio Núñez

Keyword(s):

Inferior Vena Cava ◽

Atrial Flutter ◽

Inferior Vena ◽

Vena Cava ◽

Typical Atrial Flutter ◽

Isthmus Block ◽

Atrial Flutter Ablation

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Typical Atrial Flutter Ablation: Conduction Across the Posterior Region of the Inferior Vena Cava Orifice May Mimic Unidirectional Isthmus Block

Journal of Cardiovascular Electrophysiology ◽

10.1111/j.1540-8167.2000.tb00333.x ◽

2000 ◽

Vol 11 (4) ◽

pp. 387-395 ◽

Cited By ~ 27

Author(s):

MARCO SCAGLIONE ◽

RICCARDO RICCARDI ◽

LEONARDO CALÒ ◽

PAOLO DONNA ◽

FILIPPO LAMBERTI ◽

...

Keyword(s):

Inferior Vena Cava ◽

Atrial Flutter ◽

Inferior Vena ◽

Vena Cava ◽

Posterior Region ◽

Typical Atrial Flutter ◽

Isthmus Block ◽

Atrial Flutter Ablation

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Impact of cavotricuspid isthmus depth on the ablation index for successful first-pass typical atrial flutter ablation

Scientific Reports ◽

10.1038/s41598-021-01846-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Manabu Kashiwagi ◽

Akio Kuroi ◽

Yosuke Katayama ◽

Kosei Terada ◽

Suwako Fujita ◽

...

Keyword(s):

Success Rate ◽

Atrial Flutter ◽

Vena Cava ◽

Receiver Operating Curve ◽

Cavotricuspid Isthmus ◽

Ablation Index ◽

Typical Atrial Flutter ◽

Linear Ablation ◽

First Pass ◽

Atrial Flutter Ablation

AbstractCavotricuspid isthmus (CTI) linear ablation has been established as the treatment for typical atrial flutter. Recently, ablation index (AI) has emerged as a novel marker for estimating ablation lesions. We investigated the relationship between CTI depth and ablation parameters on the procedural results of typical atrial flutter ablation. A total of 107 patients who underwent CTI ablation were retrospectively enrolled in this study. All patients underwent computed tomography before catheter ablation. From the receiver-operating curve, the best cut-off value of CTI depth was < 4.1 mm to predict first-pass success. Although the average AI was not different between deep CTI (DC; CTI depth ≥ 4.1) and shallow CTI (SC; CTI depth < 4.1), DC required a longer ablation time and showed a lower first-pass success rate (p < 0.01). In addition, the catheter inversion technique was more frequently required in the DC (p < 0.01). The lowest AI sites of the first-pass CTI line were determined in both the ventricular (2/3 segment of CTI) and inferior vena cava (IVC, 1/3 segment of CTI) sides. The best cut-off values of the weakest AIs at the ventricular and IVC sides for predicting first-pass success were > 420 and > 386, respectively. Among patients with these cut-off values, the first-pass success rate was 89% in the SC and 50% in the DC (p < 0.01). Although ablation parameters were not significantly different, the first-pass success rate was lower in the DC than in the SC. Further investigation might be required for better outcomes in deep CTIs.

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Prospective randomized comparison of a steerable versus a non-steerable sheath for typical atrial flutter ablation

EP Europace ◽

10.1093/europace/eup434 ◽

2010 ◽

Vol 12 (3) ◽

pp. 402-409 ◽

Cited By ~ 19

Author(s):

S. Matsuo ◽

T. Yamane ◽

M. Tokuda ◽

T. Date ◽

M. Hioki ◽

...

Keyword(s):

Atrial Flutter ◽

Typical Atrial Flutter ◽

Atrial Flutter Ablation ◽

Steerable Sheath

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P1428The outcome of atrial fibrillation ablation in patients undergoing radiofrequency ablation, guided by novel indices incorporating force, time and power

EP Europace ◽

10.1093/europace/euaa162.353 ◽

2020 ◽

Vol 22 (Supplement_1) ◽

Author(s):

T Rattanakosit ◽

K Franke ◽

H Marshall ◽

T Agbaedeng ◽

P Sanders ◽

...

Keyword(s):

Atrial Fibrillation ◽

Radiofrequency Ablation ◽

Contact Force ◽

Lesion Size ◽

Fluoroscopy Time ◽

Procedure Time ◽

Time Integral ◽

Ablation Index ◽

Force Time ◽

Af Recurrence

Abstract Background Ablation index (AI) and Lesion Size Index (LSI) are novel parameters that incorporates contact force, time, and power in a weighted formula. Recent studies have shown that such indices predict lesion size and durability of pulmonary vein isolation (PVI). However, the outcomes of ablation guided by indices of force-time-power, such as PV reconnections and atrial fibrillation recurrence, have not been well characterised. Objectives To determine the association between indices of force-time-power and acute PV reconnections, procedure and fluoroscopy time and AF recurrence in patients undergoing radiofrequency PVI. Methods PUBMED and EMBASE were searched using the terms "catheter ablation" AND "Ablation index" OR "Contact force" OR "Force time integral" OR "lesion size" from inception through 22 May 2019. Studies reporting the procedure time, ablation time, fluoroscopy time, and incidence of AI acute and late reconnection and AF recurrence were included. Result Six studies were included in this study with 530 patients, which n = 416 were paroxysmal AF and 114 non-paroxysmal AF. All procedural characteristics (procedure, radiofrequency, and fluoroscopy times) were similar between AI guided and non-AI guided ablation (p > 0.05). Two studies comparing mean PV reconnections in AI guided vs. AI Blinded. Two studies compared minimum AI in reconnected vs. non-reconnected PV segments. Acute PV segment reconnection was associated with a lower minimum AI vs. non-reconnection. In 3 studies reporting AI guided vs. AI blinded ablations, AI was associated with an increased freedom from AF after average follow-up of 12 months. Conclusions Radiofrequency ablation guided by AI/LSI was associated with lower acute PV reconnection rates and improved AF freedom after PVI. There was no difference in fluoroscopy, ablation or procedure time with the use of these novel parameters. Abstract Figure.

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Area Under the Real-Time Contact Force Curve (Force-Time Integral) Predicts Radiofrequency Lesion Size in an In Vitro Contractile Model

Journal of Cardiovascular Electrophysiology ◽

10.1111/j.1540-8167.2010.01750.x ◽

2010 ◽

Vol 21 (9) ◽

pp. 1038-1043 ◽

Cited By ~ 162

Author(s):

DIPEN C. SHAH ◽

HENDRIK LAMBERT ◽

HIROSHI NAKAGAWA ◽

ARNE LANGENKAMP ◽

NICOLAS AEBY ◽

...

Keyword(s):

Real Time ◽

Contact Force ◽

Lesion Size ◽

Force Curve ◽

The Real ◽

Time Integral ◽

Radiofrequency Lesion ◽

Force Time ◽

Force Time Integral

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P5752Assessment of force-time integral on radiofrequency lesion size in an in vitro swine contractile model using force sensing technology

European Heart Journal ◽

10.1093/eurheartj/ehy566.p5752 ◽

2018 ◽

Vol 39 (suppl_1) ◽

Author(s):

W S Lee ◽

K J Choi ◽

G B Nam ◽

Y H Kim ◽

J Kim ◽

...

Keyword(s):

Lesion Size ◽

Force Sensing ◽

Time Integral ◽

Sensing Technology ◽

Radiofrequency Lesion ◽

Force Time ◽

Force Time Integral

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Impact of a formula combining local impedance and conventional parameters on lesion size prediction

10.22541/au.161411895.57129623/v1 ◽

2021 ◽

Author(s):

Masateru Takigawa ◽

Masahiko Goya ◽

Hidehiro Iwakawa ◽

Claire Martin ◽

Tatsuhiko Anzai ◽

...

Keyword(s):

Surface Area ◽

Lesion Size ◽

Contact Forces ◽

Lesion Depth ◽

Positive Correlation ◽

Time Integral ◽

Combined Indices ◽

Force Time ◽

Tissue Reactions ◽

The Impact

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 (30W, 40W, and 50W), contact forces (8g, 15g, 25g, and 35g), and durations (10-180s) 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/Initial LI) was additionally assessed. Results: 375 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 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 and FTI*%LID provided significantly stronger correlation with lesion depth (ρ=0.834:P<0.0001 and ρ=0.809P<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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A case report of pulmonary vein isolation with radiofrequency catheter using superior vena cava approach in patient with paroxysmal atrial fibrillation and inferior vena cava filter

European Heart Journal - Case Reports ◽

10.1093/ehjcr/ytaa562 ◽

2021 ◽

Vol 5 (2) ◽

Author(s):

Masatoshi Narikawa ◽

Masayoshi Kiyokuni ◽

Junya Hosoda ◽

Toshiyuki Ishikawa

Keyword(s):

Atrial Fibrillation ◽

Inferior Vena Cava ◽

Left Atrium ◽

Inferior Vena ◽

Superior Vena ◽

Vena Cava ◽

Ivc Filter ◽

Transseptal Puncture ◽

Mapping Catheter ◽

Steerable Sheath

Abstract Background Transseptal puncture and pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) are generally performed via the inferior vena cava (IVC). However, in cases where the IVC is inaccessible, a specific strategy may be needed. Case summary An 86-year-old woman with paroxysmal AF and an IVC filter in situ was referred to our hospital for ablation therapy. An IVC filter for pulmonary embolism and deep venous thrombosis had been implanted 15 years prior, therefore we selected a transoesophageal echocardiography (TOE)-guided transseptal puncture using a superior vena cava (SVC) approach. After the single transseptal puncture, we performed fast anatomical mapping, voltage mapping by multipolar mapping catheter, and then PVI by contact force-guided radiofrequency catheter using a steerable sheath. Following the ablation, bidirectional conduction block between the four pulmonary veins and the left atrium was confirmed by both radiofrequency and mapping catheter. No complications occurred and no recurrence of AF was documented in the 12 months after the procedure. Discussion When performing a transseptal puncture during AF ablation, an SVC approach, via access through the right internal jugular vein, enables the sheath to directly approach the left atrium without angulation and improves operability of the ablation catheter. Combining the use of general anaesthesia, TOE, a steerable sheath, and contact force-guided ablation may contribute to achieving minimally invasive PVI with a single transseptal puncture via an SVC approach.

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