Recurrence Rate Of Atrial Flutter Research Articles

Pulsed Field Ablation to Treat Paroxysmal Atrial Fibrillation: Safety and Effectiveness in the AdmIRE Pivotal Trial.

Evidence from clinical trials of early pulsed field ablation (PFA) systems in treating atrial fibrillation has demonstrated their promising potential to reduce complications associated with conventional thermal modalities while maintaining efficacy. However, the lack of a fully integrated mapping system, a staple technology of most modern electrophysiology procedures, poses limitations in lesion creation and workflow options. A novel variable-loop PFA catheter integrated with an electroanatomic mapping system has been developed that allows for real-time nonfluoroscopic procedural guidance and lesion indexing as well as feedback of tissue-to-catheter proximity. AdmIRE (Assessment of Safety and Effectiveness in Treatment Management of Atrial Fibrillation With the Bosense-Webster Irreversible Electroporation Ablation System), a multicenter, single-arm, Food and Drug Administration investigational device exemption study, evaluated the long-term safety and effectiveness of this integrated PFA system in a large United States-based drug-refractory symptomatic paroxysmal atrial fibrillation patient population. Using the PFA catheter with a compatible electroanatomic mapping system, patients with drug-refractory symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation. The primary safety end point was primary adverse event within 7 days of ablation. The primary effectiveness end point was a composite end point that included 12-month freedom from documented atrial tachyarrhythmia (ie, atrial fibrillation, atrial tachycardia, atrial flutter) episodes, failure to achieve pulmonary vein isolation, use of a nonstudy catheter for pulmonary vein isolation, repeat procedure (except for one redo during blanking), taking a new or previously failed class I or III antiarrhythmic drug at higher dose after blanking, or direct current cardioversion after blanking. At 30 centers, 277 patients with paroxysmal atrial fibrillation (61.5±10.3 years of age; 64.3% male) in the pivotal cohort underwent PFA. More than 25% of the procedures were performed without fluoroscopy. Median (Q1, Q3) pulmonary vein isolation procedure, fluoroscopy, and transpired PFA application times were 81.0 (61.0, 112.0), 7.1 (0.00, 14.3), and 31.0 (24.8, 40.9) minutes, respectively. The primary adverse event rate was 2.9% (8 of 272), with the most common complication being pericardial tamponade. The 12-month primary effectiveness end point was 74.6%. The 1-year freedom from atrial fibrillation, atrial tachycardia, or atrial flutter recurrence rate after blanking was 75.4%. Substantial improvements in quality of life were observed as early as 3 months after the procedure, concurrent with a reduction in multiple health care use measures. AdmIRE confirmed the safety and effectiveness of the variable-loop PFA catheter, with short procedure and PFA application times and low fluoroscopy exposure. URL: https://www.clinicaltrials.gov; Unique identifier: NCT05293639.

Comparison of Long-Term Clinical Outcomes Between Segmental and Circumferential Pulmonary Vein Isolation in Patients Undergoing Repeat Atrial Fibrillation Ablation.

Circumferential pulmonary vein isolation (CPVI) has supplanted segmental PVI (SPVI) as standard procedure for atrial fibrillation (AF). However, there is limited evidence examining the efficacy of these strategies in redo ablations. In this study, we investigated the difference in recurrence rates between SPVI and CPVI in redo ablations for PV reconnection.Methods and Results: This study retrospectively enrolled 543 patients who had undergone AF ablation between 2015 and 2017. Among them, 167 patients (30.8%, including 128 male patients and 100 patients with paroxysmal AF) underwent redo ablation for recurrent AF. Excluding 26 patients without PV reconnection, 141 patients [90 patients of SPVI (Group 1) and 51 patients of CPVI (Group 2)] were included. The AF-free survival rates were 53.3% and 56.9% in Group 1 and Group 2, respectively (P=0.700). The atrial flutter (AFL)-free survival rates were 90% and 100% in Group 1 and Group 2, respectively (P=0.036). The ablation time was similar between groups, and there no major complications were observed. For redo AF ablation procedures, SPVI and CPVI showed similar outcomes, except for a higher AFL recurrence rate for SPVI after long-term follow-up (>2 years). This may be due to a higher probability of residual PV gaps causing reentrant AFL.

Is prophylactic ablation of the cavotricuspid and peri-incisional isthmus justified in patients with postoperative atrial flutter after right atriotomy?

The two most common postoperative atrial flutter (AFL) circuits after right atriotomy are the cavotricuspid isthmus (CTI) dependent and the lateral, peri-incisional. We investigated whether radiofrequency ablation (RFA) of both circuits results in more favorable long-term outcomes. Single-center retrospective cohort study of consecutive patients who underwent RFA of AFL after open-heart surgery. The effect of surgery type and RFA strategy on AFL recurrence was evaluated. One hundred and forty-two patients (mean age 64.5 ± 12.7 years, 65.% male) were enrolled. Patients with right atrial (RA) flutter (n = 124) were divided into two groups based on the index RFA procedure: only one RA circuit was ablated (Group 1, n = 84, 67.7%) or both the CTI and the peri-incisional circuit ablated (Group 2, n = 40, 32.3%). The previous open-heart surgery was categorized based on the extension of the RA incision: limited (Type A) or extended (Type B) atriotomy. After a mean follow-up of 36 ± 28 months, flutter recurrence was not different among patients with limited RA atriotomy (25% vs. 22% in Groups 1A and 2A, respectively, p = 1.0). However, after type B surgery, ablation of both AFL circuits was associated with a reduced recurrence rate (63% vs. 26% in Groups 1B and 2B, respectively, p = .002). In patients with postoperative RA flutter after extended right atriotomy, ablation of both the CTI and the peri-incisional isthmus significantly reduces the AFL recurrence rate. Prophylactic ablation of both isthmi, even if not proven to support reentry, is reasonable in this population.

Long-Term Efficacy of Prophylactic Cavotricuspid Isthmus Ablation during Atrial Fibrillation Ablation in Patients Without Typical Atrial Flutter: a Prospective, Multicentre, Randomized Trial.

Background and ObjectivesCavotricuspid isthmus (CTI) block is easily achieved, and prophylactic ablation can be performed during atrial fibrillation (AF) ablation. However, the previous study was too small and short-term to clarify the efficacy of this block.MethodsPatients who underwent catheter ablation for paroxysmal AF were enrolled, and patients who had previous or induced atrial flutter (AFL) were excluded. We randomly assigned 366 patients to pulmonary vein isolation (PVI) only and prophylactic CTI ablation (PVI vs. PVI+CTI).ResultsThere was no significant difference in procedure time between the two groups because most CTI blocks were performed during the waiting time after the PVI (176.8±72.6 minutes in PVI vs. 174.2±76.5 minutes in PVI+CTI, p=0.75). All patients were followed up for at least 18 months, and the median follow-up was 3.4 years. The recurrence rate of AF or AFL was not different in the 2 groups (25.7% in PVI vs. 25.7% in PVI+CTI, p=0.92). The recurrence rate of any AFL was not significantly different in the 2 groups (3.3% in PVI vs. 1.6% in PVI+CTI, p=0.31). The recurrence rate of typical AFL also was not different (0.5% in PVI vs. 0.5% in PVI+CTI, p=0.99).ConclusionsIn this large and long-term follow-up study, prophylactic CTI ablation had no benefit in patients with paroxysmal AF without typical AFL.Trial RegistrationClinicalTrials.gov Identifier: NCT02031705

Abstract 14549: Outcome of Radiofrequency Catheter Ablation of Cavo-tricuspid Isthmus Dependent Flutter in Patients With Adult Congenital Heart Disease

Introduction: Both typical cavo-tricuspid isthmus (CTI) dependent (or its equivalent) and atypical atrial flutter (AFL) are common in adults with congenital heart disease (CHD) either due to its inherent cardiac anatomy or as a result of prior surgical procedures. Radiofrequency catheter ablation is routinely used as a therapeutic option. Hypothesis: Patients with CHD will have an improvement in systemic ventricular ejection fraction and a decreased incidence of atrial arrhythmias after ablation. Methods: A retrospective study was conducted on 99 patients with CHD who underwent ablation for clinical AFL at a single institution between 2010 and 2019. Of these patients, 62 had CTI-AFL. The 2 patients with unspecified CHD were excluded. CHD was divided into 3 categories according to the American College of Cardiology Task Force 1 of the 32nd Bethesda Conference - simple, moderate severity, and great complexity lesions. Outcomes of ablation at 1 year follow up were assessed. Results: Typical counterclockwise CTI-AFL was seen in 50 patients. The mean age was 49.1±13.6 years old with 29 (48.3%) females. Of the 60 patients, 35% (n=21) had simple lesions, 51.7% (n=31) had moderate lesions, and 13.3% (n=8) had great complexity lesions. The mean left or systemic ventricular ejection fraction (EF) significantly improved on follow-up echo among patients with simple CHD (49.1±13.1 to 56.5±4.7%, p=0.018) and moderate CHD (49.5±14.9 to 54±8.5%, p=0.02), but did not change among patients with great complexity CHD (52.5±6 to 52.5±9.25%, p=0.9). There was a significantly increased incidence of atrial fibrillation (9.5% vs. 16.1% vs. 50%, p=0.04) post ablation among simple, moderate, and great complexity lesions, respectively, but no significant difference in the recurrence rate of atrial flutter (p=0.3). Conclusions: Patients who underwent CTI-AFL ablation showed an improvement in EF in patients with simple and moderate CHD. There was also a significantly increased incidence in the development of atrial fibrillation post ablation in CHD with great complexity compared to simple or moderate CHD.

Clinical features and outcomes of radiofrequency catheter ablation of atrial flutter in children

Objective: To explore the clinical features of atrial flutter (AFL) and evaluate the efficacy of radiofrequency catheter ablation (RFCA) for AFL in children. Method: Data were collected and analyzed on 50 consecutive pediatric AFL patients (male 37/female 13) who underwent electrophysiology study and RFCA from February 2009 to November 2016 in a case observational study. The average age was (6.2±3.5) years and body weight was (23.7±13.5) kg. Heart structure was normal in 26 patients. Twenty-four patients had congenital heart disease (CHD) and among them 22 patients underwent repaired surgery before. Patients were followed-up for 1 month to 7 years after RFCA. Clinical features and the outcomes of RFCA in AFL patients were analyzed. Result: The average onset age was (4.2±3.3) years. Of these patients, 84% had persistent AFL and 16% paroxysmal AFL. AFL with sick sinus syndrome (SSS) occurred in 36% patients without statistically significant difference between the groups with and without CHD (38.9%(7/18) vs. 61.1%(11/18), respectively, P=0.239 5); 49 patients underwent RFCA except one case with atrial standstill during the procedure. The total acute success rate was 96%. The follow-up recurrence rate was 8%.No complication of the procedures was observed. The cavotricuspid isthmus-dependent AFL occurred in all patients without CHD. However, in the children with CHD after the repair surgery 10 (45%) cases were with cavotricuspid isthmus-dependent AFL, 4 (8%) with atrial scars-dependent AFL, and 8(16%) with both cavotricuspid isthmus and atrial scars-dependent AFL. Conclusion: RFCA was effective and safe for pediatric AFL. There is no difference on the acute success rate, the follow-up AFL recurrence rate, as well as occurrence of SSS between the groups with and without CHD. AFL patients with CHD included the cavotricuspid isthmus-dependent AFL, atrial scars-dependent AFL or both.

Surgical technique and the mechanism of atrial tachycardia late after open heart surgery

Diverse atrial tachycardias (ATs) can develop after open heart surgery. The aim of our study was to examine the determinants of the mechanism of postoperative AT. One hundred patients with AT occurring at least 3 months after open heart surgery were studied. Patients were grouped according to the atrial incision applied at the time of surgery. During 127 electrophysiology procedures, 151 ATs were studied. Eighty-eight patients had cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), 49 patients had at least one non-CTI-dependent AFL and 11 patients had focal AT. While CTI-dependent AFL was equally prevalent across groups, the finding of a non-CTI-dependent AFL was progressively more common as more extensive atriotomy was applied (p < 0.001). Among patients who had right atrial (RA) operations, RA incisional tachycardia was the most common non-CTI-dependent circuit, while the finding of perimitral or left atrial (LA) roof-dependent AFL was associated with LA atriotomy (p = 0.002 and p = 0.041, respectively). After adjustment for possible confounders, surgical group remained independent predictor of non-CTI-dependent AFLs (p < 0.001). No predictor was identified for focal AT, which originated from typical predilection sites and in 36% from the vicinity of surgical scar. Radiofrequency ablation was highly effective for all ATs, but the recurrence rate of AFL and atrial fibrillation was high at 22% and 27%, respectively, during 19 ± 15 months of follow-up. While CTI-dependent AFL is the most common AT late after open heart surgery, atypical AFL becomes progressively more common with more extensive atriotomy. Right atrial incisional tachycardia is the dominant non-CTI-dependent AFL after opening of the RA, while a perimitral or roof-dependent LA circuit can be expected after LA operations.

A simple and definite proof of complete cavotricuspid isthmus block

Complete bidirectional block of the cavotricuspid isthmus (CTI) after radiofrequency ablation of typical atrial flutter is an established endpoint. Methods to determine completeness of block are subject to debate, 3‐6 since the ultimate electrophysiological proof does not seem to exist. Additionally, because of increasing economic constraints, the number of usable catheters and poles may become limited. The criterion for clockwise (CW) CTI block based on the anterior right atrium (RA) activation sequence during septal CTI pacing has been proposed to overcome the limitations of other criteria. 7 Pastor et al. elegantly and meticulously evaluate the clinical significance of this method, validating it as a powerful predictor of a freedom of recurrence after more than 3 years. Several issues are to be raised. First, in this retrospective series, three types of ablation catheters have been used which may partially affect the conclusion that can be drawn from this study: a solid 4 mm-tip catheter, a solid 8 mm-tip catheter, and an openirrigation 4 mm-tip catheter. It seems that the solid 4 mm-tip catheter was the least effective and accounted for the majority of recurrences. Secondly, the importance of obtaining non-ambiguous evidence of complete bidirectional CTI block is stressed again. Atrial flutter recurrence rate was only 3% in the presence of bidirectional block vs. 22% in the case of unidirectional block and 67% in the absence of block (P , 0.001 vs. bidirectional block). This is not a new observation but interestingly and, in our opinion, of major importance, CW CTI block, as demonstrated by completely descending anterior RA activation sequence during septal CTI pacing, was simultaneously proven by differential pacing in only 64% of these cases. The limited sensitivity of septal differential pacing was attributed to the unclear local CTI electrogram interpretation (due to the low voltage and fragmented potentials) and was observed in 36% of cases, which is similar to our experience. 5 Moreover, CTI anfractuous anatomy 8,9 makes detailed assessment of the ablation line difficult. We still think that accurate activation mapping of the anterior RA activation sequence during septal CTI pacing is of prime importance to clearly identify complete CTI block. The usefulness of a multipolar catheter is stressed out once more in this paper, with its distal poles placed along the antero-inferior RA wall but in the most immediate vicinity of the ablation line. Many cases of localized slow (yet persistent) conduction are then easily ruled out.

Long-Term Outcomes After Catheter Ablation of Cavo-Tricuspid Isthmus Dependent Atrial Flutter

Background— Despite the success of catheter ablation of cavotricuspid isthmus–dependent atrial flutter (AFL), important postablation outcomes are ill-defined. The purpose of our study was to analyze long-term outcomes after catheter ablation of cavotricuspid isthmus–dependent AFL. Methods and Results— A meta-analysis was performed of articles reporting clinical outcomes after catheter ablation of AFL published between January 1988 and July 2008. The analysis included 158 studies comprising 10 719 patients (79% men, 59.8�0.5 years old, 46% left atrial enlargement, 46% heart disease, 42% with history of atrial fibrillation, 14.3�0.4 months of follow-up). The overall acute success rate adjusted for reporting bias was 91.1% (95% CI, 89.5 to 92.4), 92.7% (95% CI, 90.0 to 94.8) for 8- to 10-mm tip/or irrigated radiofrequency catheters, and 87.9% (95% CI, 84.2 to 90.9) for 4- to 6-mm tip catheters ( P &gt;0.05). Atrial flutter recurrence rates were significantly reduced by use of 8- to 10-mm tip or irrigated radiofrequency catheters (6.7% versus 13.8%, P &lt;0.05) and by use of bidirectional cavotricuspid isthmus block as a procedural end point (9.3% versus 23.6%, P &lt;0.05). The AFL recurrence rate did not increase over time. The overall occurrence rate of atrial fibrillation after AFL ablation was 33.6% (95% CI, 29.7 to 37.3) but was 52.7% (95% CI, 47.8 to 57.6) in patients with a history of atrial fibrillation before ablation and 23.1% (95% CI, 17.5 to 29.9) in those without atrial fibrillation before ablation ( P &lt;0.05). The incidence of atrial fibrillation increased over time in both groups; however, 5 years after ablation, the incidence of atrial fibrillation was similar in those with and without atrial fibrillation before ablation. The acute complication rate was 2.6% (95% CI, 2 to 3). The mortality rate during follow-up was 3.3% (95% CI, 2.4 to 4.5). Antiarrhythmic drug use after ablation was 31.6% (95% CI, 25.6 to 37.8). The long-term use of coumadin was 65.9%, (95% CI, 43.8 to 82.8). Quality of life data were very limited. Conclusions— AFL ablation is safe and effective. Ablation technology and procedural end points have greater influences on AFL recurrences than on acute ablation success rates. Atrial fibrillation is common after AFL ablation. Almost one third of patients take antiarrhythmic drugs after AFL ablation. Atrial fibrillation before AFL ablation may indicate a more advanced state of electric disease.

Abstract 5684: Long-Term Outcomes after Catheter Ablation of Atrial Flutter: A Meta-Analysis

Clinical outcomes after catheter ablation of atrial flutter (AFL) vary widely in reported literature. The puropose of this study was to analyze long-term outcomes after cathteter ablation of AFL using meta-analys. Meta-analysis was performed of articles published from 1988 – 2007 with outcomes after catheter ablation of cavotricuspid isthmus (CTI) dependent AFL. The analysis included 110 studies comprising 7946 patients (79% male, 59.8±0.5 years, 43% left atrial enlargement, 49% heart disease, 16±12 months follow up). The acute success rate was 97% (95% CI 95–98%) with cooled (8 –10mm tip or irrigated) radiofrequency catheters and 95% (94 –96%) when bidirectional CTI block was the endpoint. Recurrence rate of AFL was 4% (3– 6%) with cooled catheters. Use of bidirectional CTI block as ablation endpoint decreased AFL reccurrence to 8% (^−10%) versus 18% (14 –22%) without CTI as endpoint. AFL recurrence rate did not increase over time. Mortality was 3% (2– 4%) during follow up. The overall occurrence rate of atrial fibrillation (AF) after AFL ablation was 25% (21–29%). In patients with AF prior to ablation, AF occurred in 46% (41–51%) compared to 16% (11–22%) without AF prior to ablation. Five years after ablation, the AF rates were similar in those with and without AF prior to ablation (Figure ). Antiarrhythmic drug use post ablation was 28% (22–36%). The long term use of coumadin was not described. AF is common after AFL ablation and may limit the clinical utility of this procedure. 28% of patients require antiarrhythmic drugs after AFL ablation. AF before ablation may indicate a more advanced electrical disease.

Atrial Fibrillation–Atrial Flutter Interactions

An appreciation of the article by Moreira et al in the current issue of Circulation 1 requires an understanding of the close interrelationship between atrial fibrillation (AF) and atrial flutter (AFL). These authors have understood this interrelationship and applied it to their data to advance the approach to both AF and AFL ablation. Key to this understanding is the recognition that cavotricuspid isthmus (CTI)–dependent AFL almost always develops from antecedent AF of variable duration.2–5 This is because in almost all instances, it is during the AF that a functional line of block (LoB) necessary for the development of AFL forms between the superior and inferior vena cavae. This LoB acts as a critical lateral boundary that prevents short-circuiting of the AFL reentrant circuit. Thus, in the vast majority of instances, without preceding AF, there can be no AFL. The most recent additional support of this concept comes from the report by Ellis et al,6 which found that of 363 patients who presented with only CTI-dependent AFL and who underwent CTI ablation, long-term follow-up (mean of 39±11 months) demonstrated newly recognized AF in 82%. It also should be noted that, as Moreira et al1 recognize, in some patients, a LoB between the vena cavae may be fixed (ie, anatomic) rather than functional. In such patients, AF may not be required for AFL to develop. Article p 2786 As Moreira et al1 further recognize, their report does not answer all the questions about the interrelationships of AF and AFL as they relate to AF ablation, …

Carto System Reduced Chronic Recurrence Rate of Typical AFL Ablations

The recurrence rate after ablation of typical atrial flutter (AFL) is still higher than that of other supraventricular tachyarrhythmias. The purpose of the present study was to determine whether performing ablation using electro-anatomical mapping (CARTO) as guide is able to reduce the incidence of AFL recurrences during the follow-up. Our study population comprises two groups of patients with AFL who underwent linear ablation of cavo-tricuspidal isthmus: 1) from 1996 to 2002, the bidirectional block at level of isthmus was confirmed by conventional method such as changes of propagation sequence on the Halo catheter and/or occurrence of double potential on ablation line (Conv group); 2) from 2002 to 2005, the bidirectional block was confirmed by CARTO system (CARTO group). We enrolled 150 consecutive patients (age 63.0±11.9 yrs). The follow-up period averaged 921 days. The recurrence rate of AFL of Conv group was 12.4% (n=14/113) during 1189 days, while the recurrence rate of CARTO group was 8.1% (n=3/37) during 140 days. In patients who experienced recurrences, the isthmus length was longer than in patients who did not (30 vs 24 mm). The recurrence rate of AFL during the follow-up seems to be lower in patients in whom ablation was performed by means of CARTO system. An isthmus length greater than 30 mm is predictor of AFL recurrence.

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

Recurrence rate of atrial flutter after initial presentation in patients on drug treatment

Atrial flutter (AFl) recurrence after initial in-patient presentation, cardioversion, and drug treatment is almost universal, often leading to rehospitalization and risk of serious clinical consequences. Radiofrequency ablation of AFl, which has an excellent safety record, should be evaluated as a first-line approach for most patients with AFl.

Acute resumption of conduction in the cavotricuspid isthmus after catheter ablation in patients with common atrial flutter. Real-time evaluation and long-term follow-up.

Cavotricuspid isthmus conduction (CIC) is closely associated with the maintenance and recurrence of common atrial flutter (AFL). This study systematically sought to assess the prevalence and characteristics of acute CIC recovery during AFL ablation and to define its predictors and its relationship with the results of long-term follow-up. A total of 124 consecutive patients (105 men, 19 women, mean age 58 +/- 11 years) who underwent successful AFL ablation were included. The procedure endpoint was defined as complete bi-directional CIC block. During an observation period of 30 min, the incidence of CIC restoration was 34.% in patients and 39.8% in applications. It increased with increasing block time and decreased over time during the observation period. Block time in successful burns followed by persistent block was shorter than in those followed by CIC resumption (12 +/- 6 vs 33 +/- 12 s, P<0.0001). A negative correlation between block time and resumption time was found (r = - 0.57, P<0.001). Patients with permanent pacemakers had a higher incidence of acute CIC resumption than those without pacemakers (5/7 vs 29/117, P = 0.007). The AFL recurrence rate was 4.8% during a mean follow-up period of 21 +/- 8 months. Our results suggest that acute CIC resumption may be a potential risk for clinical AFL recurrence during long-term follow-up. Acute CIC resumption in common AFL ablation varies in terms of incidence and time course. Block time has a predictive value for acute CIC recovery. Observation time can be shortened if block time is short. With longer block time, it is essential to observe for a longer period in order to minimize CIC resumption.

High recurrence rate of atrial flutter after initial presentation in patients on drug treatment: case for ablation as first line therapy

High recurrence rate of atrial flutter after initial presentation in patients on drug treatment: case for ablation as first line therapy

Atrial fibrillation after atrial flutter ablation.

Typical atrial flutter is caused by a re-entrant circuit confined to the right atrium (RA). It involves the “atrial flutter isthmus” which is a protected narrow isthmus of conduction, bounded on one side by the inferior vena cava, the eustachian ridge and the coronary sinus ostium and by the tricuspid valve annulus on the other. Clinically atrial flutter is frequently associated with atrial fibrillation and the mechanism for this association has yet to be elucidated. Several types of atrial flutter exist. Typical atrial flutter, or counterclockwise atrial flutter is characterized by negative “sawtooth” flutter waves in leads II, III and aVF on the electrocardiogram. In this form of flutter the impulse is conducted counterclockwise up the atrial septum, with epicardial breakthrough superiorly in the right atrium where it then travels down the free wall of the RA to re-enter the atrial septum. Reverse typical atrial flutter, with positive “sawtooth” flutter waves in leads II, III and aVF on an electrocardiogram, is characterized by impulse conduction opposite to that in typical atrial flutter, in the clockwise direction. In incisional atrial flutter, after repair of congenital heart defects, the re-entrant circuit involves areas of block caused by the incision and interestingly often involves the atrial flutter isthmus as well. A left atrial flutter exists but has not been well characterized, and involves a circuit around one or more of the pulmonary veins or the mitral valve annulus [1,2]. Standard treatment for atrial flutter with antiarrhythmics has changed over time. As compared to class IA agents, class I and class III agents have been shown to be more effective and safer in supression of atrial flutter. Despite the availability of these pharmacologic agents, it is difficult to suppress atrial flutter completely with pharmacotherapy even when multiple agents are used and antiarrhythmics are no longer the treatment of choice for typical atrial flutter. Prospective studies comparing catheter ablation and anti-arrhythmic therapy have shown catheter ablation to be associated with a lower recurrence rate of atrial flutter and fibrillation, a lower rehospitalization rate and improved sense of well being [3‐5]. Thus radiofrequency catheter ablation at the ‘atrial flutter isthmus’ is now considered the treatment of choice, with successful ablation occurring in >90% of patients. Successful ablation of atrial flutter is confirmed by the presence of bidirectional conduction block in the flutter isthmus. Recurrence of atrial arrhythmias following successful ablation of atrial flutter is related to ei

Predictors of success in radiofrequency catheter ablation of atrial flutter.

Radiofrequency catheter ablation of typical atrial flutter at the isthmus between the tricuspid annulus and the inferior vena cava is established. However in selected patients, the creation of a continuous linear lesion at the targeted isthmus requires a lengthened procedure or is not feasible at all and atrial flutter recurrences are common. In a retrospective analysis, we found that an intraoperatively determined distance between the tricuspid annulus and the inferior vena cava of <.2.5 cm is an independent predictor of a lengthened or failed ablation procedure. Additional equipment, e.g., long introducer sheaths, adapted ablation catheter design, or irrigated tip ablation, as well as alternative ablation approaches, e.g., linear lesions between the tricuspid annulus and Eustachian ridge, have been invented in order to increase the acute success rate or decrease fluoroscopy and procedure time. In a prospective study on the effects of various conduction properties at the isthmus between tricuspid annulus and inferior vena cava following radiofrequency ablation of atrial flutter, we showed previously that others than a complete bidirectional conduction block predicts a high recurrence rate of atrial flutter. For determination of transisthmal conduction properties following ablation, established mapping approaches are documentation of double potentials at the ablation line and right atrial activation sequence following posteroseptal and low lateral right atrial pacing. Novel threedimensional mapping systems, i.e., Carto(R) and EnSite(R), may further enhance the accuracy of conventional mapping techniques.

Sinus Node Dysfunction and Atrial Tachycardia After the Fontan Procedure: The Scope of the Problem

Similar to other atrial baffling procedures, the Fontan procedure exposes patients to ongoing morbidity and mortality. The development of the bradycardia-tachycardia syndrome can have adverse effects on already-marginal hemodynamics and ventricular function. Patients with Fontan physiology and sinus node dysfunction can be managed with antibradycardic pacemakers. Atrial arrhythmias after "completion Fontan" are difficult to treat and usually require either antiarrhythmic agents, antitachycardic pacemakers, or radiofrequency catheter ablation of the re-entrant circuit. Successful treatment of atrial flutter occurs in only 50% to 70% of patients. There is a high recurrence rate of atrial flutter with any of the accepted management strategies. Copyright 1998 by W.B. Saunders Company