Additional Cavotricuspid Isthmus Research Articles

In Silico TRials guide optimal stratification of ATrIal FIbrillation patients to Catheter Ablation and pharmacological medicaTION: the i-STRATIFICATION study.

Patients with persistent atrial fibrillation (AF) experience 50% recurrence despite pulmonary vein isolation (PVI), and no consensus is established for secondary treatments. The aim of our i-STRATIFICATION study is to provide evidence for stratifying patients with AF recurrence after PVI to optimal pharmacological and ablation therapies, through in silico trials. A cohort of 800 virtual patients, with variability in atrial anatomy, electrophysiology, and tissue structure (low-voltage areas, LVAs), was developed and validated against clinical data from ionic currents to electrocardiogram. Virtual patients presenting AF post-PVI underwent 12 secondary treatments. Sustained AF developed in 522 virtual patients after PVI. Second ablation procedures involving left atrial ablation alone showed 55% efficacy, only succeeding in the small right atria (<60 mL). When additional cavo-tricuspid isthmus ablation was considered, Marshall-PLAN sufficed (66% efficacy) for the small left atria (<90 mL). For the bigger left atria, a more aggressive ablation approach was required, such as anterior mitral line (75% efficacy) or posterior wall isolation plus mitral isthmus ablation (77% efficacy). Virtual patients with LVAs greatly benefited from LVA ablation in the left and right atria (100% efficacy). Conversely, in the absence of LVAs, synergistic ablation and pharmacotherapy could terminate AF. In the absence of ablation, the patient's ionic current substrate modulated the response to antiarrhythmic drugs, being the inward currents critical for optimal stratification to amiodarone or vernakalant. In silico trials identify optimal strategies for AF treatment based on virtual patient characteristics, evidencing the power of human modelling and simulation as a clinical assisting tool.

Electrophysiological findings, incidence, and predictors for AF recurrence after pulsed field versus radiofrequency pulmonary vein isolation. A retrospective analysis

Abstract Background Pulsed field ablation (PFA) is an emerging method for catheter ablation of atrial fibrillation (AF). Data comparing efficacy and safety of PFA compared to thermal ablation is still scarce. In this study, we compared a cohort of patients who underwent PFA with those who received very high power short duration (vHPSD) radiofrequency catheter ablation at the University Hospital Graz. Methods We analysed baseline data from both cohorts (PFA: n=231; RF: n=243). Both procedures were performed under deep sedation, using propofol and fentanyl. The PFA procedure involved 2x2x2 pulses, with additional pulses as required. RF procedures were performed using the QDOT Micro catheter to deliver 90 watts of energy over 4 seconds. Statistical analysis was performed using IBM SPSS Statistics for Windows, version 29. The Kruskal-Wallis test was used for quantitative non-parametric data in the baseline analysis, and the Man-Whitney-U test was used for quantitative non-parametric procedural data. For qualitative variables the Chi-squared test was used. A p-value of less than 0,05 was considered significant. Results Both groups were similar, apart from chronic heart failure, which was more prevalent in the RF group (p=0.003). Mean age for both groups was 62±10 years and mean body mass index did not differ as well. CHADS-VASc score was 2±2 in the RF and 2±1 in the PFA group (p=0.7). The types of AF were distributed as follows: (RF vs.PFA): PAF: 64%/61%; persAF: 34/36%; long standing persAF: 2%/3%. As to this date performing a CTI line with PFA is off-label, a significantly higher number of patients with additional flutter were ablated in the RF group. In the RF-group, 91 patients underwent additional cavotricuspid isthmus ablation, compared to only 14 patients in the PFA group (p&amp;lt;0.001). Procedural time (RF:PFA 122±min:57±26min; p&amp;lt;0.001), fluoroscopy time (RF:PFA 15±9min:19±9min; p&amp;lt;0.001) and fluoroscopy dose (RF:PFA 17±40Gycm2:15±15Gycm2, p=0.026) showed significant differences, with procedural time and fluoroscopy dose presenting lower values in the PFA group. First pass isolation was achieved more frequently in the PFA group (85% vs. 57%; p&amp;lt;0,001). There was significant difference in recurrence rates between the vHPSD and PFA groups (RF: 56/242 (28%), PFA: 38/231 (17%); p=0.005). Additionally, time to recurrence in the RF group was 138±117 days, compared to 166±84min in the PFA group. We exclude operator dependence as the same operators performed both procedures. Conclusion Based on our findings, PFA could potentially become the standard procedure for many patients. However, randomized trials are needed to confirm these findings.

Feasibility and procedural safety of the pentaspline pulsed field ablation catheter for atrial lesions beyond pulmonary vein isolation

Abstract Background The pentaspline multi-electrode pulsed-field ablation (PFA) catheter is widely used for the ablation of atrial fibrillation (AF). Given the favorable safety profile of PFA, lesions beyond pulmonary vein isolation (PVI) are increasingly performed. Purpose We aimed to assess the feasibility and safety of PFA beyond PVI with the pentaspline PFA catheter. Methods We retrospectively studied all patients who underwent PFA for atrial arrhythmias in our center between January and October 2023. Procedural characteristics and complications were compared between patients undergoing only PVI (PVI-only group) and those receiving extra-venous applications (extra-PVI group). Results We analysed 202 PFA cases. Indications for ablation included paroxysmal AF (34.7%), persistent AF (57.4%), long-standing persistent AF (5.9%) and atypical atrial flutter (2%). Redo procedures accounted for 18.8% of the total cases. PFA beyond PVI was performed in 142 (70.3%) patients. Patients in the extra-PVI group had a higher incidence of persistent AF (76.8% vs 11.7%, p&amp;lt;0.001), a higher BMI (29±5 vs 26±5 kg/m2, p=0.001) and a more dilated left atrium (LAVI: 73±24 vs 52±20 ml/m2, p&amp;lt;0.001, Table 1). PFA in this group consisted of PVI (98.6%), posterior wall isolation (PWI) (93%), mitral isthmus (MI) ablation (56.3%), a roof line (2.1%), ablation of dispersion electrograms (10.6%) and cavotricuspid isthmus (CTI) ablation (0.7%). In 22 (15.5%) patients, additional CTI ablation with radiofrequency (RF) was performed, while alcohol ablation of the vein of Marshall and RF ablation in the coronary sinus were required in 9 (6.3%) and 2 (1.4%) patients, respectively, to achieve MI block. Compared to the PVI-only group, PFA beyond PVI required a mean of 43 additional applications, a longer procedural (84±29 vs 65±22 min, p&amp;lt;0.001) and fluoroscopy time (25±10 vs 18±6 min, p&amp;lt;0.001) and had a higher fluoroscopy dose (24±35 vs 16.4±28.5 Gy.cm2, p=0.001). A three-dimensional electroanatomic map was used in 12% of cases. Acute success rates were 99% for PVI and PWI, 89% for MI ablation and 100% for roof lines and CTI ablation. Overall complication rates were similar in both groups (16.2% vs 13.3%, p=0.68, Table 2). One cardiac tamponade was observed in the extra-PVI group (0.7%) compared to 4 in the PVI-only group (6.7%, p=0.03). Among the latter, 2 incidents occurred during PVI in patients with long-standing persistent AF, precluding further extra-venous ablation. A small pericardial effusion (without hemodynamic compromise) and/or pericarditis were seen in 9.2% of patients in the extra-PVI group compared to 6.7% in the PVI-only group (p=0.78). No deaths occurred in either group. Conclusions Ablation beyond PVI with the pentaspline PFA catheter is feasible with high success rates and no apparent increase in procedural complications. However, it increases procedural duration and fluoroscopy. Notably, the majority of cardiac tamponades in this cohort occurred during PVI.

High efficacy single catheter standardized workflow for radiofrequency ablation of atrial fibrillation in the high-power short-duration era

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Dr. Valeriano and Dr. Fabbricatore have been supported by a research grant provided by the Cardiopath PhD program (University of Naples Federico II) Background Recent developments in radiofrequency (RF) ablation technologies have improved the efficacy of pulmonary vein isolation (PVI). The combination of the ablation index, lesion tags, and optimized inter-lesion distance (CLOSE protocol) has further reduced the incidence of gaps along the ablation lines. This high acute success rate challenged the use of conventional circular mapping catheters and prompted a single catheter-approach ablation strategy. Modulating the relationship between resistive and conductive heating, high-power short-duration (HPSD) ablation technology can potentially increase lesion-to-lesion consistency. A novel catheter with optimized temperature control and microelectrodes has been recently designed to further improve workflow efficiency. Purpose: This study aimed to assess the efficacy and efficiency of HPSD ablation in a standardized single-catheter workflow for PVI. Methods: Data on consecutive AF ablations performed with HPSD catheter from December 2020 to December 2021 at a single tertiary-care center were prospectively collected. The workflow consisted of a procedure sequence including single transeptal access with a bidirectional steerable sheath, 3D modeling with 3D rotational angiography, assessment of PV potentials with microelectrodes in each vein (figure 1), followed by radiofrequency encircling of the PVs using a high-power setting of 50W in a temperature- and flow-controlled mode with CLOSE-guided protocol. Isolation was validated by reassessing the previously observed PV potentials and by pacing within the lesion set. Results: A total of 73 consecutive AF patients (67% paroxysmal, 33% persistent) were included. All patients received PVI, 15 underwent additional cavotricuspid isthmus ablation and 6 received additional treatments (table 1). Mean procedure time was 68±27 min with minimal fluoroscopy time and dose (3.2±2.1 min; 4.7±3.9 Gycm2). Complications were infrequent with 1 cardiac tamponade and 1 pericarditis. First-pass isolation was achieved in 91% of the circles and validation by microelectrodes successfully identified the residual gaps with 100% of acute procedural success. In a selected cohort of 20 patients with paroxysmal AF undergoing PVI-only procedure performed by an expert operator, the ablation time was 22.8±5.1 min with a skin-to-skin time of 47.3±7.1 min (table 2). The median follow-up duration was 397 days (IQR: 367-462). AT/AF free survival rate was 90% at 12 months. Conclusions: HPSD ablation using a standardized single-catheter workflow improved the procedural efficiency of PVI and resulted in a high rate of first-pass isolation with a low recurrence rate at 12-month follow-up.

Abstract 15360: Characteristics and In-Hospital Outcomes of Patients Undergoing Pulmonary Vein Isolation With and Without Adjunctive Lesions: Insights From the Ncdr Afib Ablation Registry

Introduction: The optimal ablation strategy beyond pulmonary vein isolation (PVI) for atrial fibrillation (AFib) is undefined. No prior study has been adequately powered to evaluate real-world safety outcomes in those receiving adjunctive (adj) ablation lesions. We sought to evaluate characteristics and in-hospital complications among patients undergoing AFib ablation with PVI with and without adj lesions. Hypothesis: PVI + adj will be more common in those with persistent AF (persAF) and be associated with adverse events. Methods: Patients enrolled in the National Cardiovascular Data Registry AFib Ablation Registry undergoing first-time ablation between 2016 and 2020 were stratified into paroxysmal (PAF) and persAF, and separated into PVI only, PVI+cavotricuspid isthmus (CTI) ablation alone, PVI+adj (SVC isolation, coronary sinus, vein of Marshall, atypical atrial flutter lines, other). In-hospital outcomes were compared using multivariable logistic regression. Results: A total of 50,937 patients were included. Among PAF, as compared to PVI only, both PVI+CTI and PVI+adj were associated with prolonged hospitalization after adjustment, while there were no differences in complications. In the persAF cohort, as compared to PVI only, PVI+adj was associated with a higher risk of any complication and major complication, while no differences were observed in PVI+CTI (Table). In-hospital death was rare with no differences across groups. Conclusion: Adjunctive lesions are commonly performed in real-world practice in both PAF and persAF with varied strategies. Among PAF, additional lesions were associated with prolonged hospitalization, although not complications. Among persAF, PVI+adj, but not PVI+CTI, was associated with a higher risk of complications. While additional CTI ablation may be considered safe in persAF, further efforts to determine optimal ablation strategies beyond PVI and mitigate risk are warranted.

A novel wide-band dielectric imaging system to guide radiofrequency ablation for pulmonary vein isolation.

Recently, the wide-band dielectric mapping system Kodex-EPD was introduced. This study reports the first clinical experience using a novel system to guide pulmonary vein isolation (PVI) with radiofrequency (RF)ablation. METHODSAND RESULTS: The study included 20 consecutive patients undergoing de-novo PVI for symptomatic paroxysmal or persistent atrial fibrillation guided by Kodex-EPD. The primary efficacy endpoint was successful PVI. Secondary endpoints included procedural parameters and complications. In all 20 patients (mean age 68 ± 8 years, 12 male patients, paroxysmal fibrillation in 14/20 [70%] patients), PVI was successfully completed. One patient underwent additional cavo-tricuspid isthmus ablation for concomitant typical atrial flutter and one patient required additional ablation of a focal atrial tachycardia. A conventional three-dimensional image of the left atrium as well as the innovative endocardial panoramic view were used to guide catheter manipulation and ablation. Median procedure time was 115 [1st; 3rd quartile 93,75; 140] min and median total fluoroscopy time was 9.9 [9.7; 11.2] min, of which a median of 0.8 [0.6; 0.9] min was required to create left atrial maps. Complete left atrial imaging using Kodex-EPD was achieved within a median of 7.1 [5.7; 8.3] min. Median RFablation time was 45.1 [34.6; 58.7] min. No major complications were observed. RF ablation PVI guided by Kodex-EPD seems safe and feasible. The system provides effective three-dimensionalguidance for PVI.

Combined pulmonary vein isolation and cavotricuspid isthmus ablation shows no benefit in recurrence of atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is the mainstay of catheter ablation (CA) for atrial fibrillation (AF). Strategies have been proposed to improve the success rate of CA, such as prophylactic cavotricuspid isthmus (CTI) ablation. Despite some studies providing no, or limited, incremental benefit of CTI ablation in patients with AF, it is still frequently performed worldwide. Purpose The aim of this study is to examine whether CTI ablation, combined with PVI, is associated with improvement in recurrence of AF, compared with PVI alone in AF patients with or without atrial flutter (AFL). Methods We conducted a retrospective analysis of CA for AF performed at a tertiary center between September 2004 and December 2020. The procedures were divided in two groups: "PVI alone" and "PVI plus CTI ablation". Demographic, clinical, and procedure related data was retrieved. Atrial fibrillation recurrence rate at one year was analyzed for both groups and compared using logistic regression. Results A total of 453 procedures were analyzed: PVI alone (n=378; 83.4%) and PVI with CTI ablation (n=75; 16.6%). In the PVI alone group, 12.9% of the patients had concomitant typical AFL and in the PVI plus CTI ablation, 45.8% had typical AFL. Mean age was 57.3±12.1 years, with 63.6% male patients. At one year, AF recurrence rate was higher in the combined PVI with CTI ablation group (30.4%; n=21), compared with the PVI alone group (28.4%; n=97), with no statistical difference between the two groups (Odds Ratio [OD] 1.10; 95% confidence interval [CI] 0.62-1.94; p=0.73). In the subgroup analysis, there was no difference in recurrence between patients with AF without AFL (OR: 1.9; 95% CI: 0.39-9.36; p=0.43), and in patients with AF with concomitant AFL (OR: 10.0; 95% CI: 0.9-110.3; p=0.06). Conclusion In AF patients, irrespective of the presence of typical AFL, additional CTI ablation, compared with PVI alone, was not associated with improvement in recurrence of AF.

Cavotricuspid isthmus line in patients undergoing catheter ablation of atrial fibrillation with or without history of typical atrial flutter: A meta-analysis.

Pulmonary vein isolation (PVI) is the mainstay of catheter ablation (CA) for paroxysmal atrial fibrillation (AF). However, for persistent and long-standing persistent AF, there are no established strategies to improve the success rate of CA. Despite studies indicating that prophylactic cavotricuspid isthmus (CTI) ablation provides no or limited incremental benefit in patients with AF, it is still routinely performed worldwide. We sought to examine whether CTI ablation for AF is associated with improvement in recurrence of all-atrial arrhythmias, compared with PVI alone in patients with and without typical atrial flutter (AFL). A systematic review of PubMed, Cochrane, and Embase was performed for clinical studies including AF patients, reporting outcomes of CTI + PVI versus PVI alone. The primary efficacy endpoint was recurrence of all-atrial arrhythmias. Five studies comprising 1400 patients undergoing CTI + PVI versus PVI alone were included; 1110 patients had AF without AFL, and 290 patients had coexistent AF and AFL. After a mean follow-up of 14.4 ± 4.8 months, CTI + PVI was not associated with improvement in recurrence of all-atrial arrhythmias when compared with PVI alone (risk ratio [RR]: 1.29; 95% confidence interval [CI]: 0.93-1.79;p = .13). In the subgroup analysis, there were no differences between both groups in patients with AF without AFL (RR: 1.55; 95% CI: 0.96-2.48; p = .07), and in patients with AF and AFL (RR: 0.91; 95% CI: 0.6-1.39; p = .68). In AF patients, irrespective of the presence of typical AFL, additional CTI ablation is not associated with improvement in recurrence of all-atrial arrhythmias, compared with PVI alone.

Electrophysiological significance of the interatrial conduction including cavo-tricuspid isthmus during atrial fibrillation.

The interatrial conduction, including Bachmann's bundle, the posterior septal conduction, the anterior septal conduction, and the cavo-tricuspid isthmus, contributes to the maintenance mechanisms of atrial fibrillation in a 3D biatrial model. The interatrial conduction ablation including a cavo-tricuspid isthmus ablation significantly affects the wave dynamics of atrial fibrillation (AF) and facilitates the AF termination or atrial tachycardia conversion of the AF after the circumferential pulmonary vein isolation. Additional cavo-tricuspid isthmus ablation after the circumferential pulmonary vein isolation improves long-term rhythm outcome after clinical AF catheter ablation. Although it is known that atrial fibrillation (AF) is mainly a left atrial (LA) disease, the role of the right atrium (RA) and interatrial conduction (IAC), including the cavo-tricuspid isthmus (CTI), has not been clearly defined. We tested AF wave dynamics with or without IAC in computational modelling and the rhythm outcome of AF catheter ablation (AFCA) including CTI ablation in clinical cohort data. We evaluated the dominant frequency (DF) in 3D biatrial AF simulations integrated with 3D-computed tomograms obtained from 10 patients. The IAC was implemented at Bachmann's bundle, posterior septum and the CTI. After virtual circumferential PV isolation (CPVI), we disconnected IACs one by one, and observed the wave dynamics. We compared the long-term rhythm outcome after CPVI alone and additional CTI ablation in 846 patients with AFCA. LA-DF was higher than RA-DF in AF (P<0.001). After CPVI, the DF decreased significantly by additional IAC ablation (P=0.003), especially in the LA (P=0.016). The amount of DF reduction (P=0.020) and rates of AF termination (P<0.001) or AT conversion (P=0.021) were significantly higher after IAC ablations including CTI than those without. In clinical AFCA, the AF recurrence rate was significantly lower in patients with additional CTI ablation than CPVI alone during 25±20months' follow-up (hazard ratio 0.60 [0.46-0.79], P<0.001, Log rank P<0.001). IAC contributes to the maintenance mechanism of AF, and IAC including CTI ablation affects AF wave dynamics, facilitating AF termination in 3D biatrial modelling. Additional CTI ablation after CPVI improves the long-term rhythm outcome in clinical AFCA, potentially in a paroxysmal type with accompanying atrial flutter, or atrial dimension close to normal.

Additional cavotricuspid isthmus block ablation may not improve the outcome of atrial fibrillation ablation.

Pulmonary vein isolation (PVI) is an effective procedure for atrial fibrillation (AF). The role of additional cavotricuspid isthmus (CTI) block ablation remains controversial in AF patients without atrial flutter (AFL). Therefore, this study aimed to explore the clinical outcome of additional CTI block ablation in patients without AFL. Between January 2013 and December 2017, a total of 139 patients who did not have documented AFL and who underwent catheter ablation for AF were recruited. Fifty-seven patients were classified in additional CTI block ablation group and 82 patients were classified in without CTI group. The incidence of early-onset and late-onset atrial arrhythmia recurrence was compared between the two groups. The additional CTI group had a higher prevalence of persistent or long-standing AF and larger left atrial volume. The additional CTI group had a higher incidence of late-onset atrial arrhythmia recurrence (38.6%vs 12.2%; P<.001). When compared to without CTI group, additional CTI therapy did not have a better outcome in terms of freedom of atrial arrhythmia in subgroup analysis. The incidence of early-onset and late-onset atrial arrhythmia recurrence did not differ between additional CTI group and without CTI group in paroxysmal AF patients and nonparoxysmal AF patients after propensity scoring matching. CTI block ablation in addition to PVI for AF patients without a history of AFL or inducible AFL during ablation may not improve the clinical outcome of AF ablation in the patients with larger LA volume, nonparoxysmal AF, or post-PVI inducible AF.

Additional cavotricuspid isthmus ablation may reduce recurrent atrial tachyarrhythmia after total thoracoscopic ablation for persistent atrial fibrillation.

Unlike catheter ablation, little is known about the benefits of cavotricuspid isthmus (CTI) ablation in total thoracoscopic ablation (TTA) of atrial fibrillation (AF). This study aimed to investigate the incidence of recurrent atrial tachyarrhythmia (ATa) according to additional CTI ablation after TTA in patients with persistent AF. Among 208 consecutive patients who underwent TTA for persistent AF at the Samsung Medical Center from February 2012 to January 2016, a total of 63 patients with CTI ablation and 91 patients without CTI ablation were included in the final analysis. CTI ablation was performed in patients who had long-standing AF or atrial flutter episodes during the admission period. There was no difference in baseline characteristics between the CTI ablation and non-CTI ablation groups, except for a higher number of male patients in the CTI ablation group. The CTI ablation group showed a significantly higher survival rate free from recurrent ATa than that of the non-CTI ablation group at 5 years (52.5% vs 41.4%, P = 0.046). In the multivariable analysis, CTI ablation (hazard ratio 0.46, 95% confidence interval 0.217-0.971; P = 0.042) and left atrial volume index (hazard ratio 1.05, 95% confidence interval 1.029-1.070; P < 0.001) were significantly correlated with recurrent ATa. Patients with CTI ablation showed a better survival rate free from recurrent ATa compared with the non-CTI ablation group. The additional CTI ablation may reduce recurrent ATa after TTA in patients with documented atrial flutter or long-standing AF.

Novel Electrocardiographic Criteria forReal-Time Assessment of AnteriorMitral Line Block: "V1 Jump" and "V1 Delay".

This study hypothesized that P-wave morphology and timing under left atrial appendage (LAA) pacing change characteristically immediately upon anterior mitral line (AML) block. Perimitral flutter commonly occurs following ablation of atrial fibrillation and can be cured by an AML. However, confirmation of bidirectional block can be challenging, especially in severely fibrotic atria. The study analyzed 129 consecutive patients (66 ± 8 years, 64% men) who developed perimitral flutter after atrial fibrillation ablation. We designed electrocardiography criteria in a retrospective cohort (n= 76) and analyzed them in a validation cohort (n= 53). Bidirectional AML block was achieved in 110 (85%) patients. For ablation performed during LAA pacing without flutter (n= 52), we found a characteristic immediate V1 jump (increase in LAA stimulus to P-wave peak interval in lead V1) as a real-time marker of AML block (V1 jump≥30 ms: sensitivity 95%, specificity 100%, positive predictive value 100%, negative predictive value 88%). As V1 jump is not applicable when block coincides with termination of flutter, absolute V1 delay was used as a criterion applicable in all cases (n= 129) with a delay of 203 ms indicating successful block (sensitivity 92%, specificity 84%, positive predictive value 90%, negative predictive value 87%). Furthermore, an initial negative P-wave portion in the inferior leads was observed, which was attenuated in case of additional cavotricuspid isthmus ablation. Computational P-wave simulations provide mechanistic confirmation of these findings for diverse ablation scenarios (pulmonary vein isolation ± AML ± roof line ± cavotricuspid isthmus ablation). V1 jump and V1 delay are novel real-time electrocardiography criteria allowing fast and straightforward assessment of AML block during ablation for perimitral flutter.

Evaluation of Linear Lesions in the Left and Right Atrium in Ablation of Long‐standing Atrial Fibrillation

This randomized prospective study compared three ablation strategies in patients with long-standing persistent atrial fibrillation (LPeAF). It also explored the best procedural endpoint from among the following: circumferential pulmonary vein isolation (PVI) + left atrial (LA) linear lesions (roofline, mitral isthmus) + complex fractionated atrial electrogram (CFAE) ablation, PVI + LA linear lesions + cavotricuspid isthmus (CTI) ablation + CFAE ablation, and PVI + CFAE ablation. A total of 210 patients with LPeAF referred for catheter ablation were enrolled and randomized into three ablation groups. The patients in group A (n = 70) underwent PVI followed by LA linear and CFAE ablation; in 93% of patients the primary endpoint was achieved (five patients with incomplete linear lesions). Of the 70 patients in group B who were subjected to PVI followed by LA linear, CFAE, and CTI ablations, in 94% of patients the primary endpoint was achieved (four patients with incomplete linear lesions). All patients in group C (n = 70) successfully underwent PVI and CFAE ablation. Direct current cardioversion was performed upon PVI, CFAE elimination, and completion of linear lesions. Patients were followed-up for atrial tachyarrhythmia recurrence for at least 24 months. After a single ablation procedure, group C (36%) exhibited the lowest success compared with group A (54%) and group B (51%) (P = 0.06). At the mean follow-up of 32 ± 9 months after the final ablation procedure, 53 patients (76%) in group A, 53 (76%) in group B, and 41 (59%) in group C were in sinus rhythm without antiarrhythmic drugs (P = 0.03). In LPeAF, linear lesions in the LA help improve outcome of ablation, additional CTI ablation does not.

Comparative Efficiency of a Conventional 8-mm-Tip Triple Sphere Shaped Tip Catheter Versus an Irrigated Tip Catheter during Additional Cavotricuspid Isthmus Ablation after Pulmonary Vein Isolation

Background: It is well known that common atrial flutter has been documented after pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF). However, only one catheter can be used for reasons of insurance in Japan. This study aimed to prospectively compare an irrigated tip catheter to a conventional 8-mm-tip triple sphere shaped tip catheter during additional cavotricuspid isthmus (CTI) ablation after PVI. Methods: The study included 302 consecutive patients with PAF that underwent a PVI procedure with an irrigated tip catheter. After the procedure, 151 patients underwent a CTI ablation with an irrigated tip catheter, and a conventional 8-mm-tip triple sphere shaped tip catheter was used in the remaining 151. Radiofrequency (RF) current was applied until bidirectional isthmus block was achieved. Results: A significantly higher success rate was achieved using only the conventional catheter than with only an irrigated tip catheter (98% vs. 93%; p<0.05). A significant difference was also found in the number of RF applications (14±9 vs. 17±10; p<0.05). There were no significant differences in other parameters between two groups. No major complications occurred. Conclusion: In achieving CTI block after the PVI, RF ablation performed with a conventional 8-mm-tip triple sphere shaped tip catheter was more efficient than that with an irrigated tip catheter.

Evaluation of an Individualized Strategy of Cavotricuspid Isthmus Ablation as an Adjunct to Atrial Fibrillation Ablation

To evaluate supplementary cavotricuspid isthmus (CTI) ablation as an adjunct to atrial fibrillation (AF) ablation in selected patients. It is unclear whether routine CTI ablation is beneficial in all patients undergoing AF ablation. In patients undergoing AF ablation, additional CTI block was created only for those with typical atrial flutter (Afl) before or during the ablation. Out of 188 consecutive patients (108 male, 56 +/- 9 years), 75 underwent CTI ablation (Group CTI+) and left atrial (LA) ablation (circular mapping-guided extensive pulmonary vein isolation in all and linear LA ablation when required), while 113 underwent LA ablation alone (Group CTI-). Group CTI+ patients had smaller LA and less frequently persistent/permanent AF and linear LA ablation. Over a follow-up of 30 +/- 10 months, complications (4% vs 5%, P = NS), typical Afl occurrence (1.3% and 2.6%, P = NS) and AF recurrence (25% and 28%, P = NS) were similar. Atypical Afl was more common in Group CTI- (4 vs 14%, P = 0.026). Eighty-two percent and 79% of patients in Groups CTI+ and CTI-, respectively, remained arrhythmia free in stable sinus rhythm without antiarrhythmic drug treatment (P = NS). Avoiding supplementary CTI ablation in AF ablation patients without evidence of typical flutter does not result in a higher incidence of typical Afl. Despite more persistent/permanent AF and larger LA in patients without evidence of typical flutter, a strategy of selective supplementary ablation resulted in similar and low AF recurrence rates in the group without CTI ablation compared with the group with CTI ablation.