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Introduction: Typical atrial flutter (AFL) is a macroreentrant tachycardia in which intracardiac conduction rotates counterclockwise around the tricuspid annulus. Typical AFL has specific electrocardiographic characteristics, including a negative sawtooth‐like wave in the inferior lead and a positive F wave in lead V1. This study aimed to analyze the origin of the positive F wave in lead V1, which has not been completely understood. Methods: This study enrolled 10 patients who underwent radiofrequency catheter ablation for a typical AFL. Electroanatomical mapping was performed both during typical AFL and entrainment from the right atrial appendage (RAA). The 12‐lead electrocardiogram (ECG) and three‐dimensional (3D) electroanatomical maps were analyzed. Results: The positive F wave in lead V1 changed during entrainment from the RAA in all the cases. The 3D map during entrainment from the RAA revealed an area of antidromic capture around the RAA, which collided with the orthodromic wave in the anterior right atrium. This area of antidromic capture around the RAA was the only difference from the 3D electroanatomical map of AFL and is considered the cause of the change in the F wave in lead V1 during entrainment. Conclusion: The analysis of the differences in the 12‐lead ECG and 3D maps between tachycardia and entrainment from the RAA clearly demonstrated that activation around the RAA is responsible for the generation of the positive F wave in lead V1 of typical AFL. [ABSTRACT FROM AUTHOR]

Identification of patients at risk for atrial fibrillation (AF) after typical atrial flutter (tAFL) ablation is important to guide monitoring and treatment. The purpose of this study was to create and validate a risk score to predict AF after tAFL ablation We identified patients who underwent tAFL ablation with no AF history between 2017 and 2022 and randomly allocated to derivation and validation cohorts. We collected clinical variables and measured conduction parameters in sinus rhythm on an electrophysiology recording system (CardioLab, GE Healthcare). Univariate and multivariate logistic regressions (LogR) were used to evaluate association with AF development. A total of 242 consecutive patients (81% male; mean age 66 ± 11 years) were divided into derivation (n =142) and validation (n = 100) cohorts. Forty-two percent developed AF over median follow-up of 330 days. In multivariate LogR (derivation cohort), proximal to distal coronary sinus time (pCS-dCS) ≥70 ms (odds ratio [OR] 16.7; 95% confidence interval [CI] 5.6–49), pCS time ≥36 ms (OR 4.5; 95% CI 1.5–13), and CHADS 2 -VASc score ≥3 (OR 4.3; 95% CI 1.6–11.8) were independently associated with new AF during follow-up. The Atri-Risk Conduction Index (ARCI) score was created with 0 as minimal and 4 as high-risk using pCS-dCS ≥70 ms = 2 points; pCS ≥36 ms = 1 point; and CHADS 2 -VASc score ≥3 = 1 point. In the validation cohort, 0% of patients with ARCI score = 0 developed AF, whereas 89% of patients with ARCI score = 4 developed AF. We developed and validated a risk score using atrial conduction parameters and clinical risk factors to predict AF after tAFL ablation. It stratifies low-, moderate-, and high-risk patients and may be helpful in individualizing approaches to AF monitoring and anticoagulation. [ABSTRACT FROM AUTHOR]

Abstract Background Electroanatomical mapping is an essential tool in the ablation of typical AFL. Objectives To identify the existence of voltage patterns in the CTI voltage maps and their relevance for typical AFL ablation. Methods A voltage map of the CTI was made prior to ablation, identifying the areas of maximum voltage and their location along the CTI, allowing classification into patterns according to their distribution. A stepwise ablation approach targeting the areas of maximum voltage was conducted. The ablation characteristics were compared based on the pattern obtained. Results Two voltage patterns were identified, with differences in ablation time to bidirectional CTI block. No complications occurred. Conclusions Voltage mapping identifies patterns in the CTI with implications for typical AFL ablation.

Background: Electroanatomical mapping is an essential tool in the ablation of typical AFL. Objectives: To identify the existence of voltage patterns in the CTI voltage maps and their relevance for typical AFL ablation. Methods: A voltage map of the CTI was made prior to ablation, identifying the areas of maximum voltage and their location along the CTI, allowing classification into patterns according to their distribution. A stepwise ablation approach targeting the areas of maximum voltage was conducted. The ablation characteristics were compared based on the pattern obtained. Results: Two voltage patterns were identified, with differences in ablation time to bidirectional CTI block. No complications occurred. Conclusions: Voltage mapping identifies patterns in the CTI with implications for typical AFL ablation. [ABSTRACT FROM AUTHOR]

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Background: Catheter ablation is recommended as first-line therapy for patients with symptomatic typical AFl. Although the conventional multi-catheter approach is the standard of care for cavotricuspid isthmus (CTI) ablation, a single-catheter approach was recently described as a feasible alternative. The present study sought to compare safety, efficacy, and efficiency of single vs. multi-catheter approach for atrial flutter (AFl) ablation. Methods: In this randomized multi-center study, consecutive patients referred for AFl ablation (n = 253) were enrolled and randomized to multiple vs. single-catheter approach for CTI ablation. In the single-catheter arm, PR interval (PRI) on the surface ECG was used to prove CTI block. Procedural and follow-up data were collected and compared between the two arms. Results: 128 and 125 patients were assigned to the single-catheter and to the multi-catheter arms, respectively. In the single-catheter arm, procedure time was significantly shorter (37 ± 25 vs. 48 ± 27 minutes, p = 0.002) and required less fluoroscopy time (430 ± 461 vs. 712 ± 628 seconds, p < 0.001) and less radiofrequency time (428 ± 316 vs. 643 ± 519 seconds, p < 0.001), achieving a higher first-pass CTI block rate (55 (45%) vs. 37 (31%), p = 0.044), compared with the multi-catheter arm. After a median follow-up of 12 months, 11 (4%) patients experienced AFl recurrences (5 (4%) in the single-catheter arm and 6 (5%) in the multi-catheter arm, p = 0.99). No differences were found in arrhythmia-free survival between arms (log-rank = 0.71). Conclusions: The single-catheter approach for typical AFl ablation is not inferior to the conventional multiple-catheter approach, reducing procedure, fluoroscopy, and radiofrequency time. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) and coexistent typical atrial flutter (AFL) interventional treatment strategy remains unresolved in cardiology and cardiovascular surgery. Results of this approach remain suboptimal. There are several approaches to the interventional treatment of patients with coexistent AF and AFL: simultaneous pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) radiofrequency catheter ablation (RFCA), PVI or CTI RFCA only and two-stage approach. To our knowledge, cumulative efficacy of two-stage approach has not been previously reported. The aim. This study aimed to evaluate the efficacy of two-stage approach for interventional treatment of coexistent AF and AFL for sinus rhythm maintenance in long-term. Methods: Patients (pts) (n=34) with AF and AFL aged 4182 years (11 women) were divided into two groups (1:1): One-stage Approach (group 1; n=17): PVI+СTI RFСA and Two-stage approach (group 2; n=17): first stage CTI RFCA (group 2.1); second stage PVI in case of AF recurrence after RFCA (group 2.2). Primary endpoint (PEP) was defined as any recurrent atrial tachyarrhythmia at the end of follow-up; group 2 events have been considered after PVI. Secondary endpoint (SEP) recurrent any atrial tachyarrhythmia in groups 1 and 2 after CTI RFCA in group 2. PEP and SEP were evaluated at the end of the blind period (3 months after procedure). Results: Registered recurrent atrial tachyarrhythmia in pts who reached PEP or SEP was AF. AFL has not been detected in any cases. PEP was noted in 8 (47.06%) pts in group 1 and 1 (5.88%) pts in group 2. Further, SEP was observed in 3 pts (17.65%) in group 1 and in 4 (23.53%) pts in group 2 (p=0.671). The probability of long-term maintenance of sinus rhythm was significantly higher in Two-stage approach than in One-stage approach (94.12% and 52.94%, respectively, p=0.001). Significant differences in procedure length and fluoroscopy time have been found. Those were longer in group 1 compared to group 2.1 (p 0.001) and in group 2.2 compared to group 2.1 (procedure duration p 0.001; fluoroscopy time p=0.013). No differences were noted in length of procedure and fluoroscopy time between groups 1 and 2.2 (p=0.374 and p=0.028, respectively). Conclusion: The two-stage approach for interventional treatment of coexistent AF and AFL results in better long-term arrhythmia-free survival than one-stage approach (94.12% and 52.94%, respectively, p=0.001). CTI RFCA alone in pts with coexistent AF and AFL cause 23.53% AF recurrence rate and associated with shorter procedure duration and fluoroscopy time compared to simultaneous PVI and CTI RFCA (p 0.001).

The specifics of the anticoagulant therapy after radiofrequency ablation of the cavotricuspid isthmus have not been sufficiently studied, therefore, the recommendations for prescribing the anticoagulant therapy usually do not distinguish between atrial flutter and atrial fibrillation. In contrast to the case of atrial fibrillation, the effectiveness of the interventional treatment for typical atrial flutter reaches 90%. This procedure may save the patient from a long-term anticoagulant therapy in the absence of recurrence of typical atrial flutter. The decision to stop the anticoagulant therapy after successful radiofrequency ablation of the cavotricuspid isthmus should take into account the potential induction of atrial fibrillation in patients undergoing the interventional treatment. In addition to the CHA2DS2-VASc scale, which characterizes the patient's comorbidity, it is important to take into account the echocardiographic morphofunctional criteria to assess the risk of atrial fibrillation. Currently, this protocol is not regulated in the clinical guidelines. The analysis of the literature data and the authors' own experience allow us to conclude that the optimal time for stopping the anticoagulant therapy is a relapse-free period of 34 months after the radiofrequency ablation of the cavotricuspid isthmus, since it is at this time that the effectiveness of the interventional treatment can be objectified.

Introduction: The risk of typical atrial flutter (AFL) is increased proportionately to right atrial (RA) size or right atrial scarring that results in reduced conduction velocity. These characteristics result in propagation of a flutter wave by ensuring the macro re‐entrant wave front does not meet its refractory tail. The time taken to traverse the circuit would take account of both of these characteristics and may provide a novel marker of propensity to develop AFL. Our goal was to investigate right atrial collision time (RACT) as a marker of existing typical AFL. Methods: This single‐centre, prospective study recruited consecutive typical AFL ablation patients that were in sinus rhythm. Controls were consecutive electrophysiology study patients >18 years of age. While pacing the coronary sinus (CS) ostium at 600 ms, a local activation time map was created to locate the latest collision point on the anterolateral right atrial wall. This RACT is a measure of conduction velocity and distance from CS to a collision point on the lateral right atrial wall. Results: Ninety‐eight patients were included in the analysis, 41 with atrial flutter and 57 controls. Patients with atrial flutter were older, 64.7 ± 9.7 versus 52.4 ± 16.8 years (<.001), and more often male (34/41 vs. 31/57 [.003]). The AFL group mean RACT (132.6 ± 17.3 ms) was significantly longer than that of controls (99.1 ± 11.6 ms) (p <.001). A RACT cut‐off of 115.5 ms had a sensitivity and specificity of 92.7% and 93.0%, respectively for diagnosis of atrial flutter. A ROC curve indicated an AUC of 0.96 (95% CI: 0.93–1.0, p <.01). Conclusion: RACT is a novel and promising marker of propensity for typical AFL. This data will inform larger prospective studies. [ABSTRACT FROM AUTHOR]

Objective: The Vizigo sheath, a novel visualizable steerable sheath, has been utilized effectively in the clinical management of atrial fibrillation. However, its application in the ablation of typical atrial flutter (AFL) remains unexplored. This study aims to evaluate and compare the efficacy and safety of the Vizigo sheath against a conventional fixed sheath during catheter ablation for typical AFL., Methods: This single-center cohort study involved 60 patients undergoing their first AFL ablation procedure. Patients were divided into two groups: the Vizigo sheath group and the fixed sheath group. The primary endpoints included procedural efficiency, lesion quality, and recurrence rates., Results: The Vizigo sheath demonstrated significant advantages over the fixed sheath, including a shorter procedure time (59.8 ± 13.8 vs. 71.5 ± 11.8 min; p = 0.0008) and reduced fluoroscopy duration (0.96 ± 0.32 vs. 1.31 ± 0.24 min; p < 0.0001). The initial bidirectional block rate was also higher in the Vizigo sheath group (84% vs. 68%). A detailed analysis of the cavotricuspid isthmus (CTI) revealed significant differences in the anterior 2/3 of the CTI, where the Vizigo sheath demonstrated greater catheter contact force, higher ablation index, increased force-time integral, and larger impedance drops (all p < 0.05). In contrast, no significant differences were observed between groups in the posterior 1/3 of the CTI. Both groups achieved a 100% acute procedural success rate, with no major complications reported. During a mean follow-up period of 18.68 months, the AFL recurrence rates were comparable between the two groups (p = 0.75)., Conclusions: The Vizigo sheath enhances procedural efficiency and lesion quality during AFL ablation, particularly in challenging anatomical regions, and offers notable advantages over traditional fixed sheaths. Further studies are needed to assess its long-term clinical benefits., (© 2025 Wiley Periodicals LLC.)

Typical atrial flutter (AFL), defined as cavotricuspid isthmus (CTI)-dependent macro-re-entrant atrial tachycardia, often causes debilitating symptoms, and is associated with increased incidence of atrial fibrillation, stroke, heart failure, and death. Typical AFL occurs in patients with atrial remodeling and shares risk factors with atrial fibrillation. It is also common in patients with a history of prior heart surgery or catheter ablation. It is characterized by a recognizable ECG pattern that is highly predictive of CTI-dependent re-entry in patients without iatrogenic atrial scars. Typical AFL is difficult to manage medically due to poor efficacy of rate-controlling and antiarrhythmic drugs. Catheter ablation has been established in randomized trials to be superior to medical management in terms of safety, efficacy, and clinical outcomes including hospitalization and quality of life. Catheter ablation aims at achieving bidirectional conduction block across the CTI, which can be efficiently assessed by well-established techniques such as differential pacing. Long-term ablation success requires creating a stable transmural and continuous lesion, which can be optimized by systematic assessment of ablation parameters and lesion contiguity. The present review discusses the epidemiology, mechanisms, ECG characteristics, medical management, and catheter ablation of typical AFL., (© 2025 Wiley Periodicals LLC.)

Abstract Background Carcinoid heart disease is the cardiac manifestation of carcinoid syndrome. There is limited research on rhythm management in patients with carcinoid heart disease. The association of typical atrial flutter and carcinoid heart disease in particular is poorly described. Case presentation Here we present a case of a 77-year-old German woman with carcinoid heart disease and recurrent typical atrial flutter complicating the postoperative course after tricuspid valve replacement and its successful long-term rhythm control by ablation therapy. Conclusion There is limited evidence on rhythm management in patients with the rare diagnosis of carcinoid heart disease. Typical atrial flutter repeatedly complicated the postoperative course of our patient with carcinoid heart disease and could finally be treated curatively by ablation. Radiofrequency ablation should be considered as a valuable therapeutic component in the challenging therapy of this disease.

Functional and structural changes, the enlargement of the right atrium is the background for the development of typical atrial flutter (AFL). These changes in ECG are manifested in the morphology of the initial part of the P-wave. The aim of the study was to assess the duration and morphology of the P-wave in patients with paroxysmal and persistent AFL. The study population consisted of 131 patients with AFL, 38 women and 93 men aged 66 years (60-72), divided in 62 patients with paroxysmal and 69 with persistent AFL. P-wave duration was measured with an electrophysiological system in all leads at a paper speed of 200 mm/s. The groups did differ in terms of gender (38/24 vs. 55/14, (M/F), p=0.033). Patients with persistent AF had a longer P-wave duration – 175±26.3 ms vs. 159±22.6 ms, p=0.01, and higher creatinine concentration – 1.2±0.60 mg/dl vs. 1.08±0.68 mg/dl, p=0.007. The presence and severity of interatrial conduction block (I-none, II-partial, III-total) was related to age of the patients (60.3±12.1 vs. 64.7±-8.3 vs. 68.9±9.5 years, respectively). Patients with persistent AFL show a longer P-wave compared to paroxysmal AFL, regardless of comorbidities and antiarrhythmic drugs. The arrhythmia-related longer P-wave duration should encourage the clinicians to restore sinus rhythm earlier in order to more effectively maintain it over the long term. [ABSTRACT FROM AUTHOR]

Ablation of typical atrial flutter has a high safety and efficacy profile, but hidden pitfalls may be encountered. In some cases, a longer cycle length with isoelectric lines is associated with a different or more complex arrhythmogenic substrate, which may be missed if conduction block of the cavotricuspid isthmus is performed in the absence of the clinical arrhythmia. Prior surgery may have consistently modified the atrial substrate and complex or multiple arrhythmias associated with an isthmus-dependent circuit can be encountered. In these cases, electroanatomic mapping is useful to guide the procedure and plan an appropriate ablation strategy. [ABSTRACT FROM AUTHOR]

Isthmus-dependent flutter represents a defeated arrhythmia. Possibly one of the most outstanding successes in terms of understanding the mechanism behind it has led to an effective, relatively simple, and safe targeted therapy. Technology, fulfilling a number of the clinical electrophysiologist's dreams, has linked diagnosis and therapy in computerized systems showing real-time imagines of the right atrium, the arrhythmia circuit, and the ablation target. The entire history of clinical electrophysiology is contained in its path and atrial flutter needs to be regarded with immense respect for a large amount of knowledge that its study always engenders." [ABSTRACT FROM AUTHOR]

Atrial flutter (AFL) is a macro-reentrant arrhythmia characterized, in a 12 lead ECG, by the continuous oscillation of the isoelectric line in at least one lead. In the typical form of AFL, the oscillation is most obvious in the inferior leads, due to a macro-reentrant circuit localized in the right atrium, with the cavo-tricuspid isthmus as a critical zone.: This circuit can be activated in a counterclockwise or clockwise direction generating in II, III, and aVF leads, respectively, a slow descending/fast ascending F wave pattern (common form of typical AFL) or a balanced ascending/descending waveform (uncommon form of typical AFL). Atypical AFLs (scar-related) do not include the CTI in the circuit and show an extremely variable circuit location and ECG morphology. [ABSTRACT FROM AUTHOR]

Atrial flutter is a term encompassing multiple clinical entities. Clinical manifestations of these arrhythmias range from typical isthmus-dependent flutter to post-ablation microreentries. Twelve-lead electrocardiogram (ECG) is a diagnostic tool in typical flutter, but it is often unable to clearly localize atrial flutters maintained by more complex reentrant circuits. Electrophysiology study and mapping are able to characterize in fine details all the components of the circuit and determine their electrophysiological properties. Combining these 2 techniques can greatly help in understanding the vectors determining the ECG morphology of the flutter waveforms, increasing the diagnostic usefulness of this tool. [ABSTRACT FROM AUTHOR]

Nowadays, the pathophysiology mechanism of initiation and maintenance of reentrant arrhythmias, including atrial flutter, is well characterized. However, the anatomic and functional elements of the macro reentrant arrhythmias are not always well defined. In this article, we illustrate the anatomic structures that delineate the typical atrial flutter circuit, both clockwise and counterclockwise, paying attention to the inferior vena cava-tricuspid isthmus (CTI) and crista terminalis crucial role. Finally, we describe the left atrial role during typical atrial flutter, electrophysiologically a by-stander but essential in the phenotypic electrocardiogram (ECG). [ABSTRACT FROM AUTHOR]

Atrial flutter (AFL) is a regular supraventricular reentrant tachycardia generating a continuous fluttering of the baseline electrocardiography (ECG) at a rate of 250 to 300 beats per minute. AFL is classified based on the involvement of the cavo-tricuspid isthmus in the circuit. The "isthmic" (or type 1) AFL develops entirely in the right atrium; this circuit is commonly activated in a counter-clockwise direction, generating the common sawtooth ECG morphology in the inferior leads (slow descendent–fast ascendent). AFL can be nonisthmus dependent (type 2), often presenting with faster atrial rate and most commonly a left atrial location. [ABSTRACT FROM AUTHOR]

Purpose: Radiofrequency (RF) catheter ablation is widely accepted as a first-line therapy for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). The novel DiamondTemp (DT) catheter with temperature feedback during RF ablation has been released recently on the market. The purpose of this study was to evaluate the impact of DiamondTemp (DT) technology on ablation efficiency during AFL.Methods: In this single-center study, 30 consecutive patients with typical AFL indicated to ablation of CTI were included. The first 15 patients underwent CTI ablation using 8-mm tip catheter, and the following 15 patients underwent temperature-controlled RF ablation using DT catheter. The endpoints were number and mean total duration of RF applications, mean temperature reached in the setting of CTI, procedural times, and fluoroscopy times.Results: There were no significant differences between the two groups concerning baseline characteristics. Mean duration of the each application (71.5 s ± 30.6 vs 12.4 s ± 13.2, p value < 0.001), mean total duration of RF applications (517,73 s ± 377,96 vs 112,8 s ± 43,58; p value < 0.001), procedural times (51.6 min ± 24.2 vs 38.6 ± 8.2; p = 0.03), and fluoroscopy times (16.2 min ± 10.2 vs 8 min ± 4.24; p = 0.005) were longer in the 8-mm ablation catheter group. Mean temperature measurements (51.9 °C ± 3.59 vs 56.7 °C ± 3.34, p value < 0.003) were as well lower in the 8-mm ablation catheter group.Conclusions: Catheter ablation of CTI-dependent AFL by means of DT resulted in a significant reduction of total and single application RF delivery time, procedure, and fluoroscopy times. [ABSTRACT FROM AUTHOR]

Background: Patients with typical atrial flutter (AFL) undergoing successful cavotricuspid isthmus ablation remain at risk for future development of new-onset atrial fibrillation (AF). Conventional monitoring (CM) techniques have shown AF incidence rates of 18%–50% in these patients. Objectives: To evaluate whether continuous monitoring using implantable loop recorders (ILRs) would enhance AF detection in this patient population. Methods: Veteran patients undergoing AFL ablation between 2002 and 2019 who completed at least 6 months of follow-up after the ablation procedure were included. We compared new-onset AF detection between those who underwent CM and those who received ILRs immediately following AFL ablation. Results: A total of 217 patients (age: 66 ± 9 years; all male) participated. CM was used in 172 (79%) and ILR in 45 (21%) patients. Median follow-up duration after ablation was 4.1 years. Seventy-nine patients (36%) developed new-onset AF, which was detected by CM in 51 and ILR in 28 (30% vs 62%, respectively, P < .001). AF detection occurred at 7.7 months (IQR: 4.7–17.5) after AFL ablation in the ILR group vs 41 months (IQR: 23–72) in the CM group (P < .001). Eleven patients (5%) experienced cerebrovascular events (all in the CM group) and only 4 of these patients (36%) were on long-term anticoagulation. Conclusion: Patients undergoing AFL ablation remain at an increased risk of developing new-onset AF, which is detected sooner and more frequently by ILR than by CM. Improving AF detection may allow optimization of rhythm management strategies and anticoagulation in this patient population.

Background: Contact force (CF)-guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after 3 months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Our objective is to study recurrent atrial arrhythmia during 12-month follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA.Methods: Patients were randomised 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥ 30 s within 12 months and documented in 12-lead ECG or Holter monitor recording.Results: We included 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in final analysis. Recurrent arrhythmia was detected in 36 of 77 (47%) patients in the intervention group, and 32 of 73 patients (44%) in the control group (p = 0.51). Atrial fibrillation was detected in 23 (30%) and 29 (40%) patients in the intervention and control groups respectively. AFL was detected in 11 (14%) and 5 (7%) patients in the intervention and control groups respectively.Conclusions: Contact force-guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-month follow-up as compared with ablation blinded for contact force. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to elucidate the right atrial posterior wall (RAPW) and interatrial septum (IAS) conduction pattern during reverse typical atrial flutter (clockwise AFL: CW-AFL). Methods: This study included 30 patients who underwent catheter ablation of CW-AFL (n = 11) and counter-clockwise AFL (CCW-AFL; n = 19) using an ultra-high resolution mapping system. RAPW transverse conduction block was evaluated by the conduction pattern on propagation maps and double potentials separated by an isoelectric line. The degree of blockade was evaluated by the %blockade, which was calculated by the length of the blocked area divided by the RAPW length. IAS activation patterns were also investigated dependent on the propagation map. Results: The average %blockade of the RAPW was significantly smaller in patients with CW-AFL than those with CCW-AFL (25 [3–74]% vs. 67 [57–75]%, p < 0.05). CW-AFL patients exhibited 3 different RAPW conduction patterns: (1) a complete blockade pattern (3 patients), (2) moderate (> 25% blockade) blockade pattern (2 patients), and (3) little (< 25% blockade) blockade pattern (6 patients). In contrast, the little blockade pattern was not observed in CCW-AFL patients. Of 11 CW-AFL patients, 4, including all patients with an RAPW complete blockade pattern, had an IAS activation from the wavefront from the anterior tricuspid annulus (TA), and 6 had an IAS activation from the wavefronts from both the anterior TA and RAPW. One patient had IAS activation dominantly from the wavefront from the RAPW. Conclusions: RAPW transverse conduction blockade during CW-AFL was less frequent than during CCW-AFL, which possibly caused various IAS activation patterns. [ABSTRACT FROM AUTHOR]

Abstract Background High‐power (HP) ablation protocols are increasingly used for ablation procedures to shorten procedural times and improve short‐ and long‐term success. The ablation index (AI) combines contact force, power settings, and ablation time. It can be used in combination with HP protocols to guide operators toward standardized lesions. The purpose of this study was to evaluate both a HP and AI‐guided strategy for ablation of the cavotricuspid isthmus (CTI) in patients with typical atrial flutter (AFL). Methods In this single‐center study, consecutive patients with typical AFL (n = 52, mean age 68.7 ± 8.3 years, 21/52 [40.4%] female) underwent AI‐guided HP radiofrequency (RF) ablation of the CTI. Ablation was performed with 50 W and AI target values of 550 with a maximum ablation duration of 25 seconds per lesion. Target interlesion distance was ≤6 mm. Ablation was performed with a 3.5 mm porous tip Smarttouch SF catheter. Results Acute CTI block was achieved in 52 of 52 patients (100%), and first‐pass conduction block was achieved in 41 of 52 patients (80.4%). Spontaneous reconduction after 30 minutes waiting time occurred in 1 of 52 (1.9%) patient. Average ablation time until CTI block was 3:51 ± 1:40; 2:33 ± 1:01 minutes of bonus ablation pulses were applied after CTI block. An audible steam pop was noted in one patient (1.9%). No major complications occurred. After a mean follow‐up of 193.7 ± 152.2 days, no patient showed recurrence of typical AFL. Conclusion In this pilot study, AI‐guided HP ablation of the CTI was fast, safe, and effective.

Background: Carcinoid heart disease is the cardiac manifestation of carcinoid syndrome. There is limited research on rhythm management in patients with carcinoid heart disease. The association of typical atrial flutter and carcinoid heart disease in particular is poorly described.Case Presentation: Here we present a case of a 77-year-old German woman with carcinoid heart disease and recurrent typical atrial flutter complicating the postoperative course after tricuspid valve replacement and its successful long-term rhythm control by ablation therapy.Conclusion: There is limited evidence on rhythm management in patients with the rare diagnosis of carcinoid heart disease. Typical atrial flutter repeatedly complicated the postoperative course of our patient with carcinoid heart disease and could finally be treated curatively by ablation. Radiofrequency ablation should be considered as a valuable therapeutic component in the challenging therapy of this disease. [ABSTRACT FROM AUTHOR]

Aims: The aim was to describe the incidence of atrial fibrillation (AF) after cavotricuspid isthmus (CTI) ablation in patients with typical atrial flutter (AFL) without history of AF and to identify risk factors for new-onset AF after the procedure.Methods: A total of 191 patients with typical AFL undergoing successful CTI ablation were enrolled. Patients who had history of AF, structural heart disease, cardiac surgery, or ablation or who received antiarrhythmic drug after procedure were excluded. Clinical and electrophysiological data were collected.Results: There were 47 patients (24.6%) developing new AF during a follow-up of 3.3 ± 1.9 years after CTI ablation. Receiver operating characteristic (ROC) curves indicated that the cut-off values of left atrial diameter (LAD) and CHA2DS2-VASc score were 42 mm and 2, with area under the curve of 0.781 and 0.550, respectively. The multivariable Cox regression analysis revealed that obstructive sleep apnea (OSA) [hazard ratio (HR) 3.734, 95% confidence interval (CI) 1.470–9.484, P = 0.006], advanced interatrial block (aIAB) (HR 2.034, 95% CI 1.017–4.067, P = 0.045), LAD > 42 mm (HR 2.710, 95% CI 1.478–4.969, P = 0.001), and CHA2DS2-VASc score > 2 (HR 2.123, 95% CI 1.118–4.034, P = 0.021) were independent risk factors of new-onset AF.Conclusion: A combination of OSA, aIAB, LAD > 42 mm, and CHA2DS2-VASc > 2 was a strongly high risk for new-onset AF after ablation for typical AFL, and it had significance in postablation management in clinical practice.

Aims: The aim was to describe the incidence of atrial fibrillation (AF) after cavotricuspid isthmus (CTI) ablation in patients with typical atrial flutter (AFL) without history of AF and to identify risk factors for new-onset AF after the procedure. Methods: A total of 191 patients with typical AFL undergoing successful CTI ablation were enrolled. Patients who had history of AF, structural heart disease, cardiac surgery, or ablation or who received antiarrhythmic drug after procedure were excluded. Clinical and electrophysiological data were collected. Results: There were 47 patients (24.6%) developing new AF during a follow-up of 3.3 ± 1.9 years after CTI ablation. Receiver operating characteristic (ROC) curves indicated that the cut-off values of left atrial diameter (LAD) and CHA2DS2-VASc score were 42 mm and 2, with area under the curve of 0.781 and 0.550, respectively. The multivariable Cox regression analysis revealed that obstructive sleep apnea (OSA) [hazard ratio (HR) 3.734, 95% confidence interval (CI) 1.470–9.484, P = 0.006], advanced interatrial block (aIAB) (HR 2.034, 95% CI 1.017–4.067, P = 0.045), LAD > 42 mm (HR 2.710, 95% CI 1.478–4.969, P = 0.001), and CHA2DS2-VASc score > 2 (HR 2.123, 95% CI 1.118–4.034, P = 0.021) were independent risk factors of new-onset AF. Conclusion: A combination of OSA, aIAB, LAD > 42 mm, and CHA2DS2-VASc > 2 was a strongly high risk for new-onset AF after ablation for typical AFL, and it had significance in postablation management in clinical practice. [ABSTRACT FROM AUTHOR]

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Background: Cavotricuspid isthmus (CTI) ablation in typical atrial flutter (AFL) restores sinus rhythm in 95% of patients, which may lead to the discontinuation of oral anticoagulation during follow‐up. Therefore, we aimed to systematically review the clinical impact of oral anticoagulation in the incidence of thromboembolic events (TE) after typical AFL ablation. Methods: We searched for controlled studies evaluating the impact of anticoagulation in the incidence of TE in patients submitted to AFL ablation in MEDLINE, CENTRAL, PsycINFO database (June/2021). The primary outcome was TE events (ischemic stroke or systemic embolism). A meta‐analysis was performed deriving risk ratios (RR) and 95% confidence intervals (CI). Statistical heterogeneity was measured through I2 metric. The confidence in the evidence was appraised with Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. Results: Eight observational studies with 4870 patients were included. TE events were not significantly reduced (RR 1.18, 95% CI 0.59–2.36; n = 4870; GRADE very low). A meta‐regression showed that for each 10% increase in the prevalence of previous AF in the studied population, anticoagulation reduced TE risk in 32%. There were no significant differences regarding bleeding events (RR 2.16, 95% CI 0.43–10.97, I2 = 0%; GRADE low), but there was a lower all‐cause mortality (RR 0.24, 95% CI 0.17–0.32, GRADE low). Conclusion: The best available evidence lacks robustness and the data did not definitely associate anticoagulation after typical AFL ablation with reduced TE. [ABSTRACT FROM AUTHOR]

Sok-Sithikun Bun, Decebal Gabriel Lațcu, Ahmed Mostfa Wedn, Karim Hasni, Nadir SaoudiDepartment of Cardiology, Princess Grace Hospital, Monaco (Principality), Monaco, MonacoAbstract: The precise circuit of cavotricuspid isthmus (CTI)-dependent atrial flutters (AFLs) has been well characterized, but the recent arrival of ultrahigh-resolution mapping systems has further improved our understanding of this “old” arrhythmia. CTI-dependent AFL may be the arrhythmia for which the electrocardiograph (ECG) correlation with the mechanism may be the highest. Once the diagnosis is made (predominantly based upon the surface ECG), the therapeutic options are precisely defined, with radiofrequency catheter ablation representing an efficient strategy with a high success rate and few complications. This article will focus on the clinical perspectives for CTI-dependent AFL.Keywords: typical atrial flutter, cavotricuspid isthmus-dependent, catheter ablation

Background: The impact of structural heart disease (SHD) on safety and efficacy of catheter ablation of cavo-tricuspid isthmus-dependent atrial flutter (AFLU) is unclear. In addition, recent data suggest a higher complication rate of AFLU ablation compared to the more complex atrial fibrillation (AF) ablation procedure.Methods and Results: Within our prospective multicenter registry, 3526 consecutive patients underwent AFLU ablation at 49 German electrophysiological centers from 2007 to 2010. For the present analysis, the patients were divided into a group with SHD (n = 2164 [61.4%]; median age 69 years; 78.5% male) and a group without SHD (n = 1362 [38.6%]; 65 years; 70.3% male). In our study, SHD mainly encompasses coronary artery disease (52.6%), left ventricular ejection fraction ≤ 50% (47.6%), and hypertensive heart disease (28.0%). The primary ablation success (97%) and the incidence of major (0.2%) or moderate (1.2%) complications did not differ significantly between the two groups (P = 1.0 and 0.87, respectively). Vascular access site complications (0.6%), AV block III° (0.2%), and bleeding (≥ BARC II: 0.2%) were most common. After a median 562 days of follow-up, we observed a 2.92-fold higher one-year mortality (P < 0.0001) in patients with SHD. Patients' satisfaction with the ablation therapy (72.0% satisfied) was close to the overall subjective tachyarrhythmia-free rate (70.7%).Conclusions: The present analysis demonstrates that ablation of cavo-tricuspid isthmus dependent AFLU in patients with SHD has a comparable, excellent risk-benefit profile in our large "real-world" registry. Mortality rates expectedly are higher in patients with SHD and AFLU compared to patients without SHD. CLINICALTRIALS.GOV: NCT01197638, http://clinicaltrials.gov/ct2/show/NCT01197638. [ABSTRACT FROM AUTHOR]

Abstract Background Cavotricuspid isthmus (CTI) radiofrequency (RF) catheter ablation is the standard treatment for patients suffering from CTI‐dependent atrial flutter (AFL). The aim of this study was to compare the use in clinical practice of 8‐mm gold‐tip catheter (8mmRFC) and open‐irrigated gold‐tip catheter (irrRFC) for RF typical AFL ablation. Methods Patients with typical AFL were treated with 8mmRFC or irrRFC catheters according to investigator preferences. The primary endpoint was the cumulative radiofrequency time (CRFT). Fluoroscopy time, acute and 6‐month success rates were secondary endpoints. Results After excluding 3 patients with left AFL, 157 of the enrolled patients (median age 71.8 [interquartile range, 64.1‐76.2], 76% men, 91% in NYHA class ≤II, 65% with no structural heart disease) were analyzed: 74 (47%) subjects were treated with the 8mmRFC and 83 (53%) with the irrRFC. The median CRFT was 3 [2‐6] minutes in the 8mmRFC group and 5 [3‐7] minutes in the irrRFC group (P = .183). There were no significant differences in ablation success rates, intraprocedural CTI reconnections, audible steam pops, and procedural times. In the 8mmRFC group, a significantly lower fluoroscopy time was observed as compared to the irrRFC group (8 [5‐12] vs 15 [10‐20] minutes, P

Introduction: The right atrial posterior wall (RAPW) is known to form a conduction barrier during typical atrial flutter (AFL). We evaluated the transverse conduction properties of RAPW in patients with and without typical AFL using an ultrahigh resolution electroanatomical mapping system. Methods and Results: This study included 41 patients who underwent catheter ablation of AF, typical or atypical AFL, in whom we performed RAPW mapping with an ultrahigh resolution mapping system during typical AFL and coronary sinus ostial pacing with three different pacing cycle lengths (PCLs) (1) PCL1: PCL within 40 ms of the AFL cycle length in patients with typical AFL or 250–300 ms for those without, (2) PCL2: 400 ms, (3) PCL3: PCL just faster than the sinus rate. Local RAPW conduction block was evaluated by propagation mapping and local double potentials separated by an isoelectric line. The functional block was defined as areas blocked during shorter PCLs but conductive during longer PCLs. The degree of blockade was calculated by dividing the blocked length by RAPW length (%blockade). Only two patients demonstrated a fixed complete RAPW block (100%, %blockade). Thirty‐one patients demonstrated a partial block of RAPW, and the %blockade during PCL1‐3 was 49.4 ± 19.8%, 39.5 ± 19.2%, and 35.0 ± 22.9% in this group, respectively. Functional block areas were frequently observed above the fixed block area adjacent to the RA‐inferior vena cava junction. Transverse conduction block was more frequently observed in patients with typical AFL at any longitudinal level of RAPW. Conclusion: RAPW transverse conduction block is lower‐side dominant and greater in patients with typical AFL than those without. [ABSTRACT FROM AUTHOR]

Background: High‐power (HP) ablation protocols are increasingly used for ablation procedures to shorten procedural times and improve short‐ and long‐term success. The ablation index (AI) combines contact force, power settings, and ablation time. It can be used in combination with HP protocols to guide operators toward standardized lesions. The purpose of this study was to evaluate both a HP and AI‐guided strategy for ablation of the cavotricuspid isthmus (CTI) in patients with typical atrial flutter (AFL). Methods: In this single‐center study, consecutive patients with typical AFL (n = 52, mean age 68.7 ± 8.3 years, 21/52 [40.4%] female) underwent AI‐guided HP radiofrequency (RF) ablation of the CTI. Ablation was performed with 50 W and AI target values of 550 with a maximum ablation duration of 25 seconds per lesion. Target interlesion distance was ≤6 mm. Ablation was performed with a 3.5 mm porous tip Smarttouch SF catheter. Results: Acute CTI block was achieved in 52 of 52 patients (100%), and first‐pass conduction block was achieved in 41 of 52 patients (80.4%). Spontaneous reconduction after 30 minutes waiting time occurred in 1 of 52 (1.9%) patient. Average ablation time until CTI block was 3:51 ± 1:40; 2:33 ± 1:01 minutes of bonus ablation pulses were applied after CTI block. An audible steam pop was noted in one patient (1.9%). No major complications occurred. After a mean follow‐up of 193.7 ± 152.2 days, no patient showed recurrence of typical AFL. Conclusion: In this pilot study, AI‐guided HP ablation of the CTI was fast, safe, and effective. [ABSTRACT FROM AUTHOR]

Background: Despite many studies on new tools and strategies for cavotricuspid isthmus (CTI) ablation, there is an unmet need to improve the CTI ablation procedure. Recently, high‐power short‐duration (HPSD) ablation has been widely used for pulmonary vein (PV) isolation in atrial fibrillation. We evaluated the effectiveness and safety of HPSD for CTI ablation in atrial flutter (AFL). Methods: Eighty‐four patients who underwent CTI ablation with or without simultaneous PV isolation between January 2018 and February 2019 were enrolled in this prospective cohort study. We compared procedural characteristics, periprocedural complications, and recurrence of atrial tachyarrhythmia (ATa) between the HPSD group (50 W for 15 s) and conventional group (30 W for 60 s). Results: A total of 84 patients were divided into the HPSD (n = 42) and conventional (n = 42) groups. Bidirectional CTI block was achieved in all patients and 95% achieved bidirectional block after the first‐line ablation in both groups. Although there was no difference in the total number of ablation lines between the two groups (1.17 ± 0.7 vs 1.38 ± 0.8, P =.067), HPSD ablation significantly reduced total ablation time compared to the conventional group (236.0 ± 85.6 vs 534.2 ± 235.2 s, P <.001). One pericardial tamponade was reported in the HPSD group. During the mean follow‐up of 9.3 ± 4.8 months, CTI‐dependent AFL recurrence occurred in one patient in the HPSD group. Recurrence of ATa developed in 14 patients with no significant difference between the groups. Conclusion: Our study demonstrates that HPSD CTI ablation is safe and can shorten procedure time. [ABSTRACT FROM AUTHOR]

Background: The coronary sinus (CS) is surrounded by a myocardial coat with extensive connections to the left and right atria that contributes to the interatrial electrical connection. Whereas epicardial connections between CS musculature and the left atrium have largely been demonstrated, clinically relevant epicardial connections from the CS musculature toward the low right atrium (LRA) and epicardial connections between two regions of the right atrium remain questionable. Methods: Five patients underwent electrophysiology (EP) study for typical atrial flutter (AFl) using either conventional multipolar catheters (four patients) or three‐dimensional high‐density mapping system (one patient). Results: All five patients had a similar sequence of events during the EP studies. After several cavotricuspid isthmus (CTI) radiofrequency (RF) applications, double potentials were recorded along the ablation line while tachycardia persisted. The right atrial activation pattern strongly suggested the presence of a complete endocardial CTI line of the block. Based on the detailed conventional atrial mapping, RF applications at the middle cardiac vein/CS ostium allowed sinus rhythm restoration in four patients. High‐density mapping showed an early breakthrough site at the septal side of the ablation line, close to the CS ostium during counterclockwise AFl, in the fifth patient. RF applications at this site resulted in tachycardia termination. Conclusion: Our observations suggested the existence of epicardial fibers connecting the LRA with either the CS musculature or a remote right atrial region. When AFl ablation fails whereas evidence for the local endocardial block is observed, the operators should integrate this finding in the diagnosis and ablation strategy. [ABSTRACT FROM AUTHOR]

Background: The diagnostic accuracy of incremental atrial pacing (IP) to determine complete cavo‐tricuspid isthmus (CTI) block during typical atrial flutter (AFL) ablation is limited by both an extensive/nonlinear ablation and/or the presence of intra‐atrial conduction delay elsewhere in the right atrium. We examined the diagnostic performance of an IP variant based on the assessment of the atrial potentials adjacent to the ablation line which aims at overcoming both limitations. Methods: From a prospective population of 108 consecutive patients, 15 were excluded due to observation of inconclusive CTI ablation potentials precluding for a straight comparison between the IP maneuver and its variant. In the remaining 93, IP was performed from the low lateral right atrium and the coronary sinus ostium, with the ablation catheter positioned both at the CTI line and adjacent (<5 mm) to its septal and lateral aspect. The IP variant consisted of measuring the interval between the two atrial electrograms situated on the same side of the ablation line, opposite to the pacing site, a ≤10 ms increase indicating complete CTI block. Results: The IP maneuver and its variant were consistent with complete CTI block in 82/93 (88%) and 87/93 (93%) patients, respectively. Four patients had AFL recurrence during follow‐up: 2/4 and 4/4 had been adequately classified as incomplete block by the IP maneuver and its variant, respectively. Twenty‐three patients (24%) had significant intra‐atrial conduction delay elsewhere in the right atrium. The IP maneuver and its variant were suggestive of an incomplete CTI block in 11/23 and 4/23 in this setting (P =.028), with the later best predicting subsequent AFL relapses (2/12 vs 2/4, P =.01). Conclusions: The IP variant, which was designed to overcome the limitations of the conventional IP maneuver, accurately distinguishes complete from incomplete CTI block and helps to predict AFL recurrences after ablation. [ABSTRACT FROM AUTHOR]

Aims: Contact force (CF) sensing has emerged as a tool to guide and improve outcomes for catheter ablation (CA) for cardiac arrhythmias. The clinical benefit on patient outcomes remains unknown. To study whether CF-guided CA for typical atrial flutter (AFL) is superior to CA not guided by CF.Methods and Results: In a double-blinded controlled superiority trial, we randomized patients 1:1 to receive CA for typical AFL guided by CF (intervention group) or blinded to CF (control group). In the intervention group, a specific value of the lesion size index (LSI), estimating ablation lesions size was targeted for each ablation lesion. Patients underwent electrophysiological study (EPS) after 3 months to assess occurrence of the primary endpoint of re-conduction across the cavo-tricuspid isthmus (CTI). We included 156 patients with typical AFL, median age was 68 [interquartile range (IQR) 61-74] years and 120 (77%) patients were male. At index procedure median LSI was higher in the intervention group [6.4 (IQR 5.1-7) vs. 5.6 (IQR 4.5-6.9), P < 0.0001]. After 3 months, 126 patients (58 in intervention group) underwent EPS for primary endpoint assessment. Thirty (24%) patients had CTI re-conduction, distributed with 15 patients in each treatment group (P = 0.62). We observed no difference between treatment groups with regard to fluoroscopy, ablation, or procedure times, nor peri-procedural complications.Conclusion: Contact force-guided ablation does not reduce re-conduction across the CTI after 3 months, nor does CF-guided ablation shorten fluoroscopy, ablation, or total procedure times. [ABSTRACT FROM AUTHOR]

Background: Several studies reported that cavotricuspid isthmus-dependent atrial flutter (typical AFL) frequently coexists with atrial fibrillation (AF); however, the underlying mechanisms have not been fully investigated. This study aimed to reveal the mechanisms of the initiation of typical AFL and the association between typical AFL and AF. Methods: Among 154 consecutive patients undergoing a first catheter ablation of AF, we investigated the appearance and mechanism of spontaneous initiation of typical AFL during catheter ablation. Then, we retrospectively investigated 67 consecutive patients without a previous AF episode who underwent typical AFL ablation. The occurrence and predictors of AF after catheter ablation were evaluated. Results: During AF ablation, spontaneous initiation of typical AFL occurred during sinus rhythm in eight (5.2%) patients. The initiations of typical AFL were pulmonary vein (PV) firings except in one patient, in whom paroxysmal AF following superior vena cava firing initiated reverse typical AFL after PV isolation. After typical AFL ablation, AF occurred in 23 (34.3%) patients (mean follow up, 28.2±20.3 months). Kaplan-Meier analysis showed the occurrence of AF after typical AFL ablation to be significantly higher in the patients with a larger left atrial diameter over 40 mm (log-rank test, P=0.046). Conclusions: PV firing through AF played an important role in initiating typical AFL. The occurrence of AF after typical AFL ablation was high, and a dilated left atrium was associated with increased occurrence of AF. These findings disclosed the close relationship between typical AFL and AF, especially PV firing.

Competing Interests: The authors have no conflicts to disclose.

Background: Whether cavotricuspid isthmus (CTI) is a region of conduction slowing during typical flutter has been discussed with conflicting results in the literature. We aimed to evaluate conduction velocity (CV) along the different portions of the typical flutter circuit with a recently proposed method by means of ultra‐high‐resolution (UHR) mapping. Methods: Consecutive patients referred for typical atrial flutter (AFL) ablation underwent UHR mapping (Rhythmia, Boston Scientific). CVs were measured in the CTI as well as laterally and septally, respectively, from its lateral and septal borders. Results: A total of 33 patients (mean age: 65 ± 13 years; right atrial volume: 134 ± 57 mL) were mapped either during ongoing counterclockwise (n = 25), or clockwise (n = 3) AFL (mean cycle length: 264 ± 38 ms), or during coronary sinus pacing at 400 ms (n = 1), 500 ms (n = 1), or 600 ms (n = 3). A total of 13 671 ± 7264 electrograms were acquired in 14 ± 9 min. CTI CV was significantly lower (0.56 ± 0.18 m/s) in comparison with the lateral CV (1.31 ± 0.29 m/s; P <.0001) and the septal border CV of the CTI (1.29 ± 0.31 m/s; P <.0001). Conclusion: UHR mapping confirmed that CTI CV was systematically twice lower than atrial conduction velocities outside the CTI. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation of non-paroxysmal atrial fibrillation (non-PAF) is a therapeutic challenge especially in elderly patients. This study describes the feasibility of a posterior left atrium isolation as a substrate modification in addition to pulmonary vein isolation, the so-called Box isolation, for elderly patients with non-PAF. Methods: Two hundred twenty-nine consecutive patients who underwent Box isolations for drug-refractory non-PAF were divided into two groups according to their age; younger group comprising 175 patients aged