Characteristics of pulmonary vein gaps through a novel local impedance algorithm at repeat AF ablation procedures: preliminary results from the CHARISMA registry

Abstract Funding Acknowledgements Type of funding sources: None. Background A high incidence of pulmonary vein (PV) reconnection has been reported in patients with clinical recurrences of AF. Detailed characterization of PV gaps in terms of local impedance (LI) is still lacking. Purpose to characterize PV gaps with a novel local impedance algorithm during redo PV ablation in AF patients (pts). Methods Consecutive pts undergoing repeated AF ablation from the CHARISMA registry with complete characterization of PV gaps through local impedance at 6 Italian centers were included. A complete map of the left atrium and PVs was performed prior and after ablation through the Rhythmia mapping system. A novel RF ablation catheter with dedicated algorithm (DirectSense) was used to measure LI at the distal electrode of this catheter. Each gap was characterized in terms of LI and its variations during ablation procedure according to different ablation sites around the PVs. 7 sites around the left and right pair of PV for LI evaluation during ablation were defined: 2 for posterior sites (PS) (posterior inferior and posterior superior), 2 for anterior sites (AN) (anterior inferior and anterior superior), 1 for interior site (INF), 1 for superior site (SUP) and 1 for the carina (CAR). Ablation endpoint was PVI as assessed by entrance and exit block. Results Eighteen cases of redo AF ablation were analyzed (9 after prior RF ablation, 9 after prior cryoablation). A total of 41 PV gaps were detected (20 after RF ablation, 21 after cryoablation; mean number of gaps per pt = 2.3 ± 1.1): one gap was identified In five (27.8%) pts, 2 gaps were present in 7 (38.9%) pts, 3 gaps were detected in 2 (11.1%) pts and 4 gaps were identified in the remaining 4 (22.2%) pts. PV gaps were most common at AN sites (17, 41.5%), followed by PS sites (12, 29.3%) and CAR sites (11, 28.6%). The mean LI at gap sites was 113.9 ± 15Ω prior to ablation: it was significantly higher than LI at scar tissue closer to gap (99.7 ± 8Ω, p < 0.0001) but was significantly lower than LI at healthy tissue (120.2 ± 12Ω, p < 0.0001). LI parameters did not differ between prior ablation approach (RF vs Cryo: 115.5 ± 13Ω vs 112.2 ± 16Ω for LI at gap, p = 0.4739; 102.2 ± 6Ω vs 97.3 ± 10Ω LI at scar tissue, p = 0.0591; 16.4 ± 4Ω vs 15.8 ± 13Ω for LI drop at gap, p = 0.6647). In 14 cases (34.1%) the difference between LI at healthy tissue and LI at gap was lower than 5Ω, suggesting that this spot was not treated by RF or Cryo delivery in the previous ablation session (13 out 21 after Cryo ablation vs 1 out 20 after RF ablation, p < 0.0001). No complications during the procedures were reported. The acute procedural success was 100%, with all PVs successfully isolated in all study patients. Conclusion In our preliminary experience, PV gaps after failed PVI were most common at anterior, followed by posterior and carina sites. LI characteristics at PV gaps significantly differ from both scar and healthy tissue and could be used to target ablation deliveries.

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P441Targeted ablation of residual luminal pulmonary vein potentials through high density mapping: preliminary results from the CHARISMA registry

EP Europace ◽

10.1093/europace/euaa162.221 ◽

2020 ◽

Vol 22 (Supplement_1) ◽

Author(s):

F Solimene ◽

F M Cauti ◽

G Zucchelli ◽

V Schillaci ◽

P Rossi ◽

...

Keyword(s):

Pulmonary Vein ◽

De Novo ◽

Low Voltage ◽

Complete Characterization ◽

High Density ◽

Analysis Tool ◽

Temporal Consistency ◽

Af Ablation ◽

Density Mapping

Abstract Background A high incidence of pulmonary vein (PV) reconnection has been reported in patients (pts) with clinical recurrences of AF. Low-voltage activity beyond PVs (e.g. antral activity) may contribute to ablation failures in the long term. Detailed characterization of PV antra through high density mapping (HDM) and automated algorithm is still lacking. Purpose to characterize PV gaps and the low-voltage activity in tissue such as the PV antra during and after ablation of PVs in AF pts. Methods Consecutive pts undergoing AF ablation from the CHARISMA registry with complete characterization of residual PV antral activity were included. A complete map of the left atrium and PVs was performed prior and after ablation through the Rhythmia HDM system. A novel map analysis tool (Lumipoint - LM -) that automatically identifies split potentials and continuous activation was used sequentially on each PV component, in order to assess the presence of gaps (PVG) and residual potential within the antral scar (RAP, defined as any low voltage high frequency fractionated signal propagating within the antral scar without conduction into the vein) and characterize electrical propagation. After ablation we reassessed with repeat voltage and propagation maps that electrical quiescence was achieved. Ablation endpoint was PV isolation. Results Thirty-six cases of AF ablation were analyzed (11 de novo, 25 redo). A total of 36 PVG in 13 (36%) patients were detected after remap (1 case of de novo) or initial map of redo patients (12 cases). A total of 34 RAP in 20 cases (56%) were found: 4 (36%) cases of de novo (all after ablation and remap) and 16 (64%) cases of redo (all after initial map). In 7 (19%) cases we found at least one RAP in pts with complete absence of PV conduction. 100% of PVG (n = 36) and 89% of RAP (n = 29) were fully detected though a first pass automated annotation. In 5 RAPs (11%) an additional temporal consistency of low-voltage signal relative to neighboring activation was needed due to the very low voltage EGM (≤0.1 mV). PVGs were more common at right PV sites (n = 26, 72%) and anterior PV sites (n = 20, 55.6%) whereas RAPs were detected more frequently at left PV sites (n = 20, 59%) and anterior PV sites (n = 21, 62%). RAP showed a lower median voltage compared with PVG (0.22[0.2-0.3]mV for RAP vs 0.97[0.6-1.3]mV for PVG, p < 0.0001) whereas the median number of EGM peaks were higher (6.5[5-8] for RAP vs 3[2-4] for PVG, p < 0.0001). No complications during the procedures were reported. The acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study pts. Conclusion In our preliminary experience, local vulnerabilities in antral lesion sets were commonly discernible using HDM system both in de novo or redo patients when no PV conduction was present. The applied workflow seemed to be useful to quickly pinpoint and accelerate the search of local PV activity or concealed low-voltage activity.

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Local impedance characteristics and advanced mapping capabilities to better understand pulmonary veins reconnections during repeat AF ablation procedures: insight from the CHARISMA registry

European Heart Journal ◽

10.1093/eurheartj/ehab724.0515 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

Author(s):

L Segreti ◽

R Maggio ◽

G Bencardino ◽

G Izzo ◽

R De Lucia ◽

...

Keyword(s):

Pulmonary Veins ◽

Complete Characterization ◽

Healthy Tissue ◽

Analysis Tool ◽

Af Ablation ◽

Density Mapping ◽

The Mean ◽

The One ◽

Activation Map

Abstract Background Detailed characterization of pulmonary veins (PV) reconnection during repeat AF ablation through high-density mapping (HDM) and local impedance (LI) algorithm is still lacking. Purpose We aimed to characterize PV gaps and underlying electrical activity during and after ablation of PVs in AF patients (pts). Methods Consecutive patients (pts) undergoing redo AF ablation from the CHARISMA registry with complete characterization of PV gaps (PVG) at 8 Italian centers were included. Rhythmia mapping system was used to map the left atrium and PVs before and after ablation. LI characteristics were collected through a RF ablation catheter equipped with a dedicated LI algorithm (DirectSense). A novel map analysis tool (Lumipoint) that automatically identifies split potentials and continuous activation was used sequentially on each PV component, in order to better assess PVG. Each PVG was characterized in terms of LI and its variations during the procedure. Ablation endpoint was PVI as assessed by entrance and exit block. Results Fifty PVGs were automatically identified through the Lumipoint tool in 23 cases, mostly at anterior sites (21, 42%), followed by posterior (15, 30%) and carina (10, 20%) sites. One PVG was identified in 7 (28%) pts, 2 gaps in 10 (43.5%) pts and >2 gaps in 6 (26.1%) pts. The mean LI at PVG sites was 111.3±12Ω prior to ablation: it was significantly higher than LI at scar tissue closer to PVG (99.3±8Ω, p<0.0001) but was significantly lower than LI at healthy tissue (120.8±11Ω, p=0.0015). The mean linear extension of PVGs detected through Lumipoint was significantly lower than the one recognized through voltage map (11.5±8 mm vs 13.3±9 mm, p=0.01) whereas was comparable to the one identified through conventional activation map (11.8±7 mm, p=0.1161 vs Lumipoint). Complete identification of the whole area of PVG was achieved in 31 (62%) and 42 (84%) cases through voltage and activation map, respectively whereas the identification was only partial in 18 (36%) and 7 (14%) cases, respectively. In 1 case both voltage and activation map failed to identify a PVG. No complications during the procedures were reported. All PVs were successfully isolated in all study pts. Conclusion Advanced mapping capabilities were useful to pinpoint the search for PVGs, enabling a more targeted ablation approach vs relying on voltage mapping. LI values correlated well with PVGs characteristics and they significantly differ from both scar and healthy tissue. FUNDunding Acknowledgement Type of funding sources: None.

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P2846Focal impulse and rotor modulation ablation versus pulmonary vein isolation for the treatment of paroxysmal atrial fibrillation (FIRMAP AF study)

European Heart Journal ◽

10.1093/eurheartj/ehz748.1156 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

R Tilz ◽

C L Lenz ◽

P S Sommer ◽

N Sawan ◽

R Meyer-Saraei ◽

...

Keyword(s):

Atrial Fibrillation ◽

Pulmonary Vein ◽

Pulmonary Vein Isolation ◽

Paroxysmal Atrial Fibrillation ◽

Gold Standard ◽

Artery Aneurysm ◽

Rf Ablation ◽

Af Ablation ◽

Number Of Patients

Abstract Background Based on the assumption of trigger elimination, pulmonary vein isolation (PVI) currently presents the gold standard of atrial fibrillation (AF) ablation. Recently, rapidly spinning rotors or focal impulse formation has been raised as a crucial sustaining mechanism of AF. Ablation of these rotors may potentially obviate the need for trigger elimination with PVI. Purpose This study sought to compare the safety and effectiveness of Focal Impulse and Rotor Modulation (FIRM) guided catheter ablation only with the gold standard of pulmonary vein isolation (PVI) in patients with paroxysmal AF. Methods This was a post-market, prospective, single-blinded, randomized, multi-center trial. Patients were enrolled at three centers and equally (1:1) randomized between those undergoing conventional RF ablation with PVI (PVI group) vs. those treated with FIRM-guided RF ablation without PVI (FIRM group). Data was collected at enrollment, procedure, and at 7-day, 3-month, 6-month, and 12-month follow-up visits. The study was closed early by the sponsor. At the time of study closure, any pending follow-up visits were waived. Results From February 2016 until February 2018, a total of 51 (out of a planned 170) patients (mean age 63±10.6 years, 57% male) were enrolled and randomized. Four patients withdrew from the study prior to treatment, resulting in 23 patients allocated to the FIRM group and 24 in the PVI group. Only 13 patients in the FIRM group and 11 patients in the PVI group completed the 12-month follow-up. Statistical analysis was not completed given the small number of patients. Single-procedure effectiveness (freedom from AF/atrial tachycardia recurrence after blanking period) was 52.9% (9/17) in the FIRM group and 85.7% (12/14) in the PVI group at 6 months; and 31.3% (5/16) in the FIRM group and 80% (8/10) in the PVI group at 12 months. Repeat procedures were performed in 45.8% (11/24) patients in the FIRM group and 7.4% (2/27) in the PVI group. The acute safety endpoint [freedom from procedure-related serious adverse events (SAE)] was achieved in 87% (20/23) of FIRM group patients and 100% (24/24) of PVI group patients. Procedure related SAEs occurred in three patients in the FIRM group: 1 femoral artery aneurysm and 2 injection site hematomas. No additional procedure-related SAEs were reported >7 days post-procedure. Conclusions These partial study effectiveness results reinforce the importance of PVI in paroxysmal atrial fibrillation patients and suggest that FIRM-guided ablation alone (without PVI) is not an effective strategy for treatment of paroxysmal AF in most patients. Further study is needed to understand the effectiveness of adding FIRM-guided ablation as an adjunct to PVI in this patient group. Acknowledgement/Funding Abbot

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The role of left atrial wall thickness and pulmonary vein anatomy in success of pulmonary vein isolation using the CLOSE protocol

European Heart Journal ◽

10.1093/eurheartj/ehab724.0264 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

Author(s):

M Boussoussou ◽

B Vattay ◽

B Szilveszter ◽

M Kolossvary ◽

M Vecsey-Nagy ◽

...

Keyword(s):

Pulmonary Vein ◽

Wall Thickness ◽

Left Atrial ◽

Pulmonary Veins ◽

Logistic Regression Models ◽

Funding Sources ◽

Coronary Ct ◽

First Pass ◽

Procedural Success ◽

The Right

Abstract Introduction The CLOSE protocol is a novel contact-force guided technique for enclosing pulmonary veins in patients with atrial fibrillation (AF). Consistency and lesion contiguity are essential factors for procedural success. We sought to determine whether left atrial (LA) wall thickness (LAWT) and pulmonary vein (PV) dimensions as assessed by coronary CT angiography (CTA) could influence the efficacy of successful first-pass isolation using the CLOSE protocol. Methods In a single center, prospective study we enrolled 94 patients with symptomatic, drug-refractory AF who underwent pre-ablation left atrial CTA and initial radiofrequency catheter ablation between 2019.01–2020.09. The LA was divided into 11 regions when assessing LAWT. Additionally, the diameter and area of the PV orifices were obtained. First pass isolation was recorded separately for the right and left PVs. After the first pass ablation circles were ready, additional ablations were applied in those cases where first pass isolation was not achieved, to reach complete PV isolation. Predictors of successful first pass isolation were determined using logistic regression models that included anthropometrical, echocardiographic and CTA derived parameters. Results A total of 94 patients were included in the analysis with mean CHA2DS2-VASc score of 2.1±1.5 (mean age 62.4±12.6 years, 39.5% female). 61.7% were paroxysmal, 38.3 were persistent AF patients. Mean procedure times were 81.2±19.3 minutes. Complete isolation of all four PVs was achieved in 100% of patients. First-pass isolation rate was 76%, 71% and 54%, for the right PVs, left PVs and all four PVs, respectively. No difference was found regarding comorbidities and imaging parameters between those with and without first pass isolation. LAWT (mean of all 11 regions or separately) had no effect on the procedural outcome (all p>0.05). Out of all assessed parameters, only RSPV diameter was associated with right sided successful PVI on first pass isolation (p=0.04, OR 1.01). Conclusion The use of CLOSE protocol in AF patients resulted in high periprocedural success rate in terms of first pass isolation, independently from the thickness of the LA wall. RSPV diameter could influence the results of first pass isolation. FUNDunding Acknowledgement Type of funding sources: None.

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Safety and acute clinical outcomes of atrial fibrillation catheter ablation in octogenarians: a multicentre evaluation with a matched younger cohort

EP Europace ◽

10.1093/europace/euab116.235 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

N Karim ◽

N Kozhuharov ◽

J Jarman ◽

S Furniss ◽

R Veasey ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

De Novo ◽

Lv Function ◽

P Value ◽

Complication Rates ◽

Success Rates ◽

Af Ablation ◽

Funding Sources ◽

Procedural Success

Abstract Funding Acknowledgements Type of funding sources: None. OnBehalf Sven Knecht and the International Octogenarian AF ablation group Background Octogenarians are a fast-growing demographic with a high burden of atrial fibrillation (AF). There are limited data on procedural safety and acute outcomes of catheter ablation (CA) for AF in this group. Purpose Investigation of complications & outcomes in octogenarians undergoing CA for AF. Methods Data on all octogenarian patients who underwent AF ablation at nine European cardiology centres between 2013 and 2019 were retrospectively analysed and matched with control patients aged <80 years. The characteristics used for matching were type of AF, type of procedure (de novo or redo), & the year of procedure. Results 216 octogenarians (81.9 ± 1.9 years; 52.8% females) underwent an AF ablation procedure, and were matched with 216 patients aged <80 years (62.4 ± 9.5 years, 34.7% females), p <0.001 for both. The proportion of paroxysmal and persistent AF was 43.5% & 56.5% respectively in both groups, and 79.3% of the procedures were de novo. RF ablation made up 75.4% & 75.9% (p = 0.90) procedures in octogenarians and controls respectively. 17 complications occurred in 14 (7.9%) octogenarian patients and 11 in 11 (5.1%) patients in the younger matched cohort (p = 0.07). There were 4.2% & 1.9% major complications (p= 0.17) and 3.7% & 3.2% minor complications (p= 0.77) in the octogenarian & younger cohorts respectively. Complications in octogenarians consisted of groin complications (n = 6), pneumonia (n = 3), pericardial effusion (n = 2), phrenic nerve injury (n = 2), pulmonary oedema (n = 1), gastroparesis (n = 1), stroke (n = 1). Acute procedural success rates were 99.1% & 99.5% (p = 0.62) The complication rates were similar for RF; 6.0% vs 5.4% (p = 0.79) and Cryoballoon; 14.0% vs 4.1% (p = 0.09) in both octogenarians and younger cohort respectively. Conclusion In spite of significantly higher overall risk profile of octogenarians undergoing AF ablation, there is no difference in acute procedural success and complication rates as compared to younger patients Catheter ablation of AF in octogenerians Octogenarians n = 216 Matched Controls (aged < 80yrs) n = 216 P value Age (yrs), mean (SD)s 81.9 (1.9) 62.4(9.5) < 0.0001 Females, (%) 52.8 34.7 0.0002 CHA2DS2-VASc, mean (SD) 3.6 (1.2) 1.4 (1.3) < 0.0001 Mean LA size, mm 42.8 ± 8.3mm 45.8 ± 16.2 0.062 Impaired LV function, (%) 23.7 17.9 0.206 IHD, (%) 20.7 5.9 < 0.0001 Procedural time (mins), mean (sd) 150.6 (69.7) 148.9 (64.4) 0.914 All complications, n (%) 17 (7.9) 11 (5.1) 0.073

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LSI guided-high power short duration is safe and improves pulmonary vein isolation efficiency

European Heart Journal ◽

10.1093/eurheartj/ehab724.0390 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

Author(s):

A Di Cori ◽

S Della Volpe ◽

M Parollo ◽

L Mazzocchetti ◽

M Giannotti ◽

...

Keyword(s):

Pulmonary Vein ◽

Short Duration ◽

Pulmonary Vein Isolation ◽

High Power ◽

Rf Power ◽

Af Ablation ◽

Funding Sources ◽

Total Procedure Time ◽

Total Procedure ◽

Lesion Index

Abstract Introduction High-power short-duration (HPSD) is an increasingly used ablation strategy for pulmonary vein isolation (PVI) procedures, but Lesion Index (LSI)-guided HPSD radio-frequency (RF) application has not been described in this clinical setting. Purpose We evaluated the procedural efficiency and safety of an LSI-guided HPSD strategy for atrial fibrillation (AF) ablation. Methods Paroxysmal and persistent AF patients scheduled for AF ablation were prospectively enrolled and divided in two groups, according to the ablation power used. The LSI-HP Group included patients ablated with a RF power of 50 Watts and the LSI-LP Group included patients ablated with 35 Watts. All patients underwent only PVI under LSI guidance (LSI between 5.5 and 6 anteriorly; LSI between 4.5 and 5 posteriorly) with a point by point strategy and an inter-lesion distance <6 mm. Procedural efficiency parameters were compared between groups. Results Forty-six patients with AF (60% paroxysmal) were prospectively enrolled, 25 in the LSI-HP Group and 21 in the LSI-LP Group. They were usually male (78%) with a low-intermediate CHA2DS2-Vasc score (1.8±1.1), a preserved ejection fraction (60±6%) and moderate left atrial dilatation (45±6 mm). Baseline clinical characteristics resulted comparable between groups (p=NS). PVI was successful in all patients. RF time (30.22±9.04 vs 47.85±11.87 min, p<0.0001), total procedure time (138.7±33.2 vs 177.6±49.77, p=0.006) and fluoroscopy time (13.92±5.34 vs 23.14±10.97 min, p=0.006) were significantly lower in the LSI-HP Group. No complication or steam pops was seen in either group. Conclusions LSI-HP AF ablation significantly improves procedural efficiency, reducing ablation time, total procedural duration and fluoroscopy use, while maintaining a comparable safety profile as lower powers. FUNDunding Acknowledgement Type of funding sources: None. Figure 1 Figure 2

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Double Transseptal Puncture for Catheter Ablation of Atrial Fibrillation: Safety of the Technique and Its Use in the Outpatient Setting

Cardiology Research and Practice ◽

10.4061/2010/295297 ◽

2010 ◽

Vol 2010 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Laurent M. Haegeli ◽

Thomas Wolber ◽

Ercüment Ercin ◽

Lukas Altwegg ◽

Nazmi Krasniqi ◽

...

Keyword(s):

Atrial Fibrillation ◽

Left Atrium ◽

Pulmonary Vein ◽

Pulmonary Vein Isolation ◽

Outpatient Setting ◽

Outpatient Basis ◽

Transseptal Puncture ◽

Af Ablation ◽

Procedural Success ◽

A Minor

Introduction. For pulmonary vein isolation in patients with atrial fibrillation (AF), some centers use the double transseptal puncture technique for catheter access in order to facilitate catheter manipulation within the left atrium. However, no safety data has so far been published using this approach.Method. 269 ablation procedures were performed in 243 patients (mean age years, 75% men) using the double transseptal puncture for catheter access in all cases. Patients were considered for ablation of paroxysmal (80%), persistent (19%), and permanent (1%) AF. 230 procedures were performed on an outpatient basis (85.5%), and 26 were repeat procedures (9.7%).Results. The double transseptal puncture catheter access was successfully achieved in all patients. The procedural success with the endpoint of pulmonary vein isolation was reached in 255 procedures (95%). A total of 1048 out of 1062 pulmonary veins (99%) were successfully isolated. Major complications occurred in eight patients (3.0%). Of these, seven patients (2.6%) had pericardial effusion requiring percutaneous drainage, and one patient (0.4%) suffered a minor reversible stroke. One patient (0.4%) had a minor air embolism with transient symptoms.Conclusion. The double transseptal puncture catheterization technique allows easy catheter manipulation within the left atrium to reach the goal of acute procedural success in AF ablation. Procedure-related complications are rare, and the technique can be used safely for AF ablation in the outpatient setting.

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A novel local impedance algorithm and contact force sensing to guide high power short duration radiofrequency ablation is efficient and safe for circumferential pulmonary vein isolation

EP Europace ◽

10.1093/europace/euab116.240 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

J Schreieck ◽

D Heinzmann ◽

C Scheckenbach ◽

M Gawaz ◽

M Duckheim

Keyword(s):

Radiofrequency Ablation ◽

Pulmonary Vein ◽

Short Duration ◽

Contact Force ◽

High Power ◽

Force Sensing ◽

The Novel ◽

Rf Ablation ◽

Af Ablation ◽

Circumferential Pulmonary Vein Isolation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Local impedance (LI) drop can predict sufficient lesion formation during radiofrequency ablation (RF). Recently, a novel ablation catheter technology able to measure LI and contact force has been made available for clinical use. High power short duration (HPSD) RF ablation has been shown to be feasible for atrial fibrillation (AF) ablation with short procedure time. We used LI drop and plateau formation to guide duration of 50 Watt RF power applications for circumferential pulmonary vein isolation (PVI). Methods Consecutive patients with indication for de novo AF ablation (n = 32, age 65 ± 10 years) with paroxysmal (n = 16) or persistent (n = 16) AF underwent ultra high density 3D mapping of the left atrium and catheter ablation. Thereafter, ipsilateral PV encircling with 50 Watt RF-applications targeting an interlesion distance of ≤ 6mm and a contact force of 10-30g was performed. Duration of HPSD RF application between 7-15s was guided by impedance drop >20 Ohm and plateau formation of LI. Further ablation strategy was left to the investigator’s discretion. Esophageal temperature measurement was performed using a three thermistor catheter with temperature cut off 39.0°C. In case of temperature rise or very near esophageal contact to the circumferential line, RF application time was shortened to 7s. Patients underwent adenosine testing after PVI. Previously we performed all types of AF ablation using an LI guided HPSD ablation without contact force measurement capability in 80 patients. Results Complete PVI was achieved in all pts with only 13.5 ± 4.3 min cumulative RF application duration and an ablation procedure duration of 46.5 ± 10.4 min with the novel LI measuring catheter. First-pass isolation of ipsilateral veins was achieved in 75% of circles. Recurrence of PV conduction during waiting period (20min) and adenosine testing occured in 25% of circles, and was reablated in most patients with a single spot of HPSD application. Using 94 ± 36 RF application per patient, mean maximum LI drop was 23.6 ± 4.0 Ohm. Reconnected fibers were associated with low LI drop due to instability of contact in most cases due to breathing in case of difficult sedation of the patients. No serious complications occurred in all 32 pts using HPSD with the novel contact force catheter design. Conclusion Guiding of HPSD RF ablation by LI is highly efficient and safe. A novel local impedance algorithm in combination with contact force sensing enable short PVI times with low early recurrence of PV conduction. Prediction of permanent lesions seems possible and the only limitation seems to be unstable RF catheter contact due patients breathing. Follow up have to be waited.

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The magnitude and the course of local impedance drop to guide successful AF ablation: insight from an Italian registry

EP Europace ◽

10.1093/europace/euab116.193 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

V Schillaci ◽

G Zucchelli ◽

F Solimene ◽

A De Simone ◽

C Pandozi ◽

...

Keyword(s):

Time Course ◽

Rf Ablation ◽

Af Ablation ◽

Funding Sources ◽

A Value ◽

Successful Ablation ◽

The Mean ◽

Rf Applications ◽

Af Recurrence

Abstract Funding Acknowledgements Type of funding sources: None. Background It has been demonstrated that an ablation strategy based on local impedance (LI) algorithm is helpful in guiding successful ablation of atrial fibrillation (AF) cases. How the magnitude and the course of LI drop could impact the effectiveness of ablation has to be proved. Purpose We aimed to evaluate LI drop characteristics in predicting effective radiofrequency (RF) ablation of consecutive AF cases. Methods Consecutive patients undergoing AF ablation at 8 Italian centers were included in the CHARISMA registry. A RF ablation catheter equipped with mini-electrodes technology and a dedicated algorithm was used to measure LI and to guide ablation. For our purpose, we defined the time to drop (τ) as the time for the first deflection of LI drop to the plateau. RF applications were targeted to a LI drop of 10 Ω and were stopped when a maximum cut-off LI drop of <40 Ω was observed. Successful single RF ablation was defined according with a reduction of signal voltage by at least 50% and inability to capture local tissue on pacing. The ablation endpoint was PVI as assessed by entrance and exit block. Follow-up were scheduled at 3, 6 and 12 months post-ablation. Results 153 consecutive patients (61% paroxysmal AF, 39% persistent AF) were enrolled in the study. 3556 point-by-point first-pass RF applications of >10 s duration were performed around PVs. The mean LI drop was 13 ± 8Ω, the mean τ was 18.7 ± 13s and the median LI drop/τ was 0.67 [QI-QIII, 0.37 – 1.17] Ω/s. Both absolute drops in LI and LI drop/τ were greater at successful ablation sites (n = 3122, 88%) than at ineffective ablation sites (n = 434, 12%) (14 ± 8Ω vs 6 ± 4Ω, p < 0.0001 for LI; 0.73[0.41–1.25]Ω/s vs 0.35[0.22–0.59]Ω/s for LI drop/τ, p < 0.0001). Every 5-point increment in LI drop was associated with successful ablation, with an OR of 3.13 (95%CI: 2.7 to 3.6, p < 0.0001), reaching the highest point when a value larger than 15 Ω was observed (99.9% of acute success). A significant trend was observed from lower to higher LI drop/τ values and a value greater than 0.65 Ω/s (best cut-off value on the basis of the ROC analysis) was significantly associated with successful RF delivery with an OR of 5.54 (95%CI: 4.31 to 7.11, p < 0.0001). No complications occurred during and after procedures. At 1-year follow-up, the AF recurrence rate was 12% after the 90-day blanking period. Conclusions The magnitude and time-course of the LI drop during RF delivery were associated with effective lesion formation. This ablation strategy for PVI guided by LI technology proved safe and effective, and resulted in a very low rate of AF recurrence over 1-year follow-up.

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The role of marshall bundle epicardial connections in atrial tachycardias after atrial fibrillation ablation

EP Europace ◽

10.1093/europace/euab116.096 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

K Vlachos ◽

A Denis ◽

T Kitamura ◽

M Takigawa ◽

A Frontera ◽

...

Keyword(s):

Pulmonary Veins ◽

Mitral Annulus ◽

Af Ablation ◽

Funding Sources ◽

Ethanol Infusion ◽

Long Duration ◽

Lateral Ridge ◽

The Difference

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial tachycardias (ATs) are often seen in the context of AF ablation. Objectives We evaluated the role of the Marshall bundle (MB) network in left atrial (LA) ATs using high-density high-spatial resolution 3D mapping. Methods 199 post-AF ablation LA tachycardias were mapped in 140 consecutive patients (112 (80%) males, mean age: 61.8 years); 133 (66.8%) were macro-reentrant and 66 (33.2%) were scar-related re-entry. MB-dependent perimitral AT (PMAT) was diagnosed where the difference between the post pacing interval and the tachycardia cycle length (PPI-TCL) was <20ms in parts of the expected MB-dependent perimitral circuit (within the VOM, the ridge between the left pulmonary veins and LA appendage (LAA), the anterior LA and between 6- and 11-o’clock of the mitral annulus) and the PPI-TCL was >20ms in areas bypassed by the VOM (the distal coronary sinus (CS), the posterior LA and the mitral isthmus). MB-related re-entry was diagnosed by PPI-TCL <20ms at the left lateral ridge, posterior base of LAA, inferolateral LA or VOM ostium; and PPI-TCL >20ms in the septal annulus. Typically, in MB-dependent localized re-entry, the earliest activation was found along the MB-LA endocardial connection or MB-CS epicardial connection. Results The MB network was found to participate in 60 (30.2%) re-entrant ATs, 31 PMATs and 29 localized re-entries. High-frequency multiphasic fragmented electrograms with long duration were often recorded endocardially or epicardially at the MB-LA or MB-CS connections. The amplitude and duration of these signals were 0.5 ± 0.79 mV and 65 ± 40 ms for MB-PMATs and 0.26 ± 0.28mV and 122 ± 67 ms for MB-localized re-entries. Unipolar EGMs at the site of endocardial-epicardial breakthrough had a rS pattern in all MB-related ATs. Of 60 MB-related ATs, 49 (81.6%) terminated with RF ablation, 44 (73.3%) at the MB-LA junction and 5 (8.3%) at the MB-CS junction, while 9 (15%) terminated after 2.5-5 cc of alcohol infusion inside the vein of Marshall (VOM). Of the 31 MB-related macroreentrant ATs, 17 (54.8%) terminated at the MB-LA junction, 5 (16.1%) at the MB-CS junction and 7 (22.6%) with alcohol infusion inside the VOM. Two macroreentries (6.5%) using the MB did not terminate with RF energy either endocardially at the MB-LA junction or epicardially at the MB-CS junction, and we were unable to identify or cannulate the VOM for ethanol infusion. Of the 29 localized re-entrant ATs using the MB, 27 (93.1%) terminated at the MB-LA junction, none terminated at the MB-CS junction and 2 (6.9%) terminated after alcohol infusion. After a mean follow up of 12 months, only 4 patients (6.7%) had AT recurrence. Conclusions MB re-entrant ATs accounted for up to 29% of the left ATs after AF ablation. Ablation of the MB-LA or CS-MB connections or alcohol infusion inside the VOM is required to treat these arrhythmias. Abstract Figure.

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