Isthmus-dependent Atrial Flutter Research Articles

Abstract 14526: The Effect of Radiofrequency Catheter Ablation of Typical Atrial Flutter on Cardiac Chambers' Size and Function

Introduction: Cavo-tricuspid isthmus (CTI) dependent atrial flutter (AFL) is one of the most common atrial arrhythmias involving the right atrium (RA) for which radiofrequency catheter ablation has been widely used as a therapy of choice. However, there is limited data on the effect of this intervention on cardiac size and function. Hypothesis: CTI dependent ablation for patients with AFL will improve tricuspid valve function, biatrial enlargement, and ventricular function. Methods: A retrospective study was conducted on 468 patients who underwent CTI dependent ablation for clinical typical AFL at a single institution between 2010 and 2019. After patients with congenital or rheumatic heart disease, heart transplant recipients, or those without baseline echocardiogram were excluded, 211 patients remained in the analysis. Echocardiographic data were analyzed at baseline prior to ablation, and at early follow-up within 1-year post-ablation. Follow-up echocardiographic data was available for 130 patients. Results: Of the 211 patients with CTI-AFL, 200 had typical counterclockwise flutter. The mean age was 64.2±12.1 years old with 12% (n=26) female. The average left ventricular (LV) ejection fraction (EF) significantly improved on follow-up echo (45.55±14.26 to 49±14.4%, p=0.0075), of which 63 (48%) patients had an improvement in EF of 5% or more and 19 (25%) patients had an increased EF of 20% or more. The prevalence of moderate to severe tricuspid regurgitation (TR) was 24% (n=50) at baseline and 18% (n=22) at follow-up with no significant difference (p=0.27). However, 30% (n=39) of the patients had one grade or more improvement in their TR within the 1-year follow-up. Echocardiography also showed improvement of RA size in 48.6%, and left atrial (LA) size in 48.2% of the patients. Conclusions: Patients who underwent CTI dependent AFL ablation showed an improvement in cardiac size and function at follow-up evaluation. Although longer-term results are unknown, these findings suggest that restoration of sinus rhythm from atrial flutter is associated with improvement in TR severity, RA size, LA size, and LVEF.

Cryoballoon ablation of atypical mitral isthmus-dependent left atrial flutter.

Cryoballoon ablation of atypical mitral isthmus-dependent left atrial flutter.

The Japanese Catheter Ablation Registry (J-AB): A prospective nationwide multicenter registry in Japan. Annual report in 2018.

BackgroundTo analyze the type of ablation procedure, acute outcomes, and complications related to catheter ablation in Japan during the year of 2018.MethodThe Japanese Catheter Ablation (J‐AB) registry is a voluntary, nationwide, multicenter, prospective, observational registry, performed by the Japanese Heart Rhythm Society (JHRS) in collaboration with the National Cerebral and Cardiovascular Center using a Research Electronic Data Capture system. The procedural outcome and complications during hospitalizations were collected.ResultA total of 55 525 procedures (mean age of 64.5 years and 66.5% male) from 369 hospitals were collected. The total number of target arrhythmias was 61 610 including atrial fibrillation (AF, 65.6%), atrial flutter (AFL) or atrial tachycardia (16.7%), atrioventricular nodal reentrant tachycardia (7.4%), atrioventricular reentrant tachycardia (3.5%), premature ventricular contractions (4.1%), and ventricular tachycardia (VT, 2.0%). Over a 90% acute success rate was observed among all arrhythmias except for VT due to structural heart disease, and notably, an over 99% success rate was achieved for pulmonary vein isolation of AF and inferior vena cava‐tricuspid valve isthmus block for isthmus‐dependent AFL. Acute complications during hospitalization were observed in 1558 patients (2.8%), including major bleeding (Bleeding Academic Research Consortium: BARC criteria ≥2) in 1.1%, cerebral or systemic embolisms in 0.2%, and death in 0.1%. Acute complications were more often observed with AF ablation (P < .001), especially the first AF ablation session and with structural heart disease (P < .001).ConclusionThe J‐AB registry provided real‐world data regarding the acute outcomes and complications of ablation for the various types of arrhythmias in Japan.

Acute Success and Long-term Follow-up of Catheter Ablation of Isthmus-dependent Atrial Flutter; A Comparison of 10 mm Tip Standard, 6 mm Tip Irrigated Radiofrequency, and Cryotherapy Catheters

Radiofrequency (RF) ablation of cavotricuspid isthmus (CTI) is an effective treatment for atrial flutter (AFL). This prospective, randomized study aimed to compare cryoablation (CRYO) with 10 mm tip RF catheter ablation (10RF) and 4.0 mm tip RF irrigated catheter ablation (IRRF) regarding the efficacy, safety, and long-term prognosis.

Elevated Left Atrial Volume Index Predicts Incident Atrial Fibrillation After Typical Right Atrial Flutter Ablation.

Incident atrial fibrillation (AF) is common after cavotricuspid isthmus (CTI) dependent atrial flutter (AFL) ablation. Risk factors for the development of AF post ablation are not well understood. The purpose of this study was to identify patients undergoing CTI ablation for AFL most likely to develop AF. Retrospective chart review identified 114 consecutive patients without a history of AF or prior cardiac surgery who underwent typical CTI dependent AFL ablation between December 2013 to November 2018, who also had a complete preoperative transthoracic echocardiogram, and at least 1 year of follow-up at our medical center. We evaluated baseline characteristics, electrophysiology study (EPS) data and echocardiographic data for incidence of AF within 3 years. Incident AF was identified in 46 patients (40%) during 600 + 405 days follow-up. Left atrial volume index (LAVI) was significantly greater in patients who developed AF compared to those that did not (37 ± 12.2 ml/m2 vs 30 ± 13.4 ml/m2, p=.004), with an area under the receiver operator characteristic curve based on the LAVI of 0.7 (p = 0.004). Kaplan-Meier estimated incidence of AF was significantly greater in patients with LAVI ≥ 30 ml/m2 than LAVI < 30 ml/m2 (66% vs 27%, p=0.004). Risk of incident AF in patients with LAVI > 40 mL/m2 was similar to that of LAVI 30-40 ml/m2 (67% vs 63%, respectively, p=0.97). In multivariable analysis LAVI remained the sole independent predictor of incidence AF after CTI AFL ablation. LAVI ≥ 30 ml/m2 is associated with significantly increased risk of incident AF following CTI ablation for typical AFL. HATCH <2 was notably not an independent predictor of AF after AFL ablation.

Comparison of Atrial Remodeling Caused by Sustained Atrial Flutter Versus Atrial Fibrillation

BackgroundAtrial flutter (AFL) and atrial fibrillation (AF) are associated with AF-promoting atrial remodeling, but no experimental studies have addressed remodeling with sustained AFL. ObjectivesThis study aimed to define the atrial remodeling caused by sustained atrial flutter (AFL) and/or atrial fibrillation (AF). MethodsIntercaval radiofrequency lesions created a substrate for sustained isthmus-dependent AFL, confirmed by endocavity mapping. Four groups (6 dogs per group) were followed for 3 weeks: sustained AFL; sustained AF (600 beats/min atrial tachypacing); AF superimposed on an AFL substrate (AF+AFLs); sinus rhythm (SR) with an AFL substrate (SR+AFLs; control group). All dogs had atrioventricular-node ablation and ventricular pacemakers at 80 beats/min to control ventricular rate. ResultsMonitoring confirmed spontaneous AFL maintenance >99% of the time in dogs with AFL. At terminal open-chest study, left-atrial (LA) effective refractory period was reduced similarly with AFL, AF+AFLs and AF, while AF vulnerability to extrastimuli increased in parallel. Induced AF duration increased significantly in AF+AFLs and AF, but not AFL. Dogs with AF+AFLs had shorter cycle lengths and substantial irregularity versus dogs with AFL. LA volume increased in AF+AFLs and AF, but not dogs with AFL, versus SR+AFLs. Optical mapping showed significant conduction slowing in AF+AFLs and AF but not AFL, paralleling atrial fibrosis and collagen-gene upregulation. Left-ventricular function did not change in any group. Transcriptomic analysis revealed substantial dysregulation of inflammatory and extracellular matrix-signaling pathways with AF and AF+ALs but not AFL. ConclusionsSustained AFL causes atrial repolarization changes like those in AF but, unlike AF or AF+AFLs, does not induce structural remodeling. These results provide novel insights into AFL-induced remodeling and suggest that early intervention may be important to prevent irreversible fibrosis when AF intervenes in a patient with AFL.

Staged surgical treatment of patients with combination of non-paroxysmal form of atrial fibrillation and isthmus-dependent atrial flutter

Objective. To improve the results of treatment for the patients with non-paroxysmal atrial fibrillation (AF) in combination with isthmus-dependent (typical) atrial flutter (AFL) by determining the optimal surgical tactics.Material and methods. The research based on the study of treatment results for 37 patients who are consequentially underwent thoracoscopic radiofrequency fragmentation (TRF) of the left atrium (LA) in the period from April 2017 to December 2019. All of the patients suffered from a combination of 2 types of arrhythmias: non-paroxysmal AF and AFL. Depending on history of catheter ablation (CA) of cavotricuspid isthmus (CTI) before TRF, all patients divided into 2 groups: group 1 - there was anamnesis of CA of CTI before TRF (N = 16; 43%); group 2 - there was no CA of CTI before TRF of the LA (N = 21; 57%). In the postoperative period, all patients underwent examination and interviewed regarding cardiac arrhythmias. At the time of April 1, 2020, information about heart rhythm and its disorders during follow-up period was received from 100% of patients. The duration of the follow-up period after TRF was 17 (3; 35) months.Results. There was no supraventricular tachyarrhythmias (SVT) during all follow-up period after TRF among the patients of group 1. There was 8 patients (38%) of group 2 with AFL, which is developed in the period from 1 to 6 months after TRF. All these patients underwent a CA of CTI after the end of a “blanking” period. There was 2 of 8 patients with developing of SVT after CA of CTI. The source of new rhythm disorder was the ablation line formed during TRF on the roof of the LA.Conclusion. In order to achieve long-term freedom from SVT requiring surgical intervention in patients suffering from a non-paroxysmal AF in combination with a typical AFL it is reasonable to perform catheter radiofrequency ablation of CTI at the first stage before TFR of the LA.

P993Incidence of atrial fibrillation early after cavotricuspid isthmus ablation

Abstract Background Atrial fibrillation (AF) is a common finding in patients undergoing cavotricuspid isthmus ablation for isthmus dependent right atrial flutter (RAF). Little is known about the time of its occurrence. Purpose We aimed to investigate the incidence of AF early after RAF ablation in a well-defined, prospective cohort. Methods A total of 255 participants with RAF ablation from 5 centers and at least one completed follow-up were included. Structured clinical follow-up was performed at 3, 6 and 12 months including a 24 hour Holter-ECG. The endpoint was incidence of AF detected clinically or by Holter-ECG. Risk factors associated with the occurrence of AF were assessed using separate, univariate Cox proportional-hazards models. Results Mean age was 67 years, 80% were male and previous episodes of AF were known in 40%. Over a mean follow-up of 7.4 (±4.4) months AF was detected in 35 (13.7%) participants after RAF ablation (Figure A). After 3, 6 and 12 months AF was detected in 18 (7.1%), 30 (11.7%) and 34 (13.3%) patients. No difference in the incidence of AF after RAF ablation was found comparing patients with and without a history of AF (log-rank p value = 0.44) (Figure B). Comparing patients with and without AF during follow-up, there was no difference in age (68 vs 66 years, p = 0.36), sex (69 vs 81% male, p = 0.08), prior heart failure (29 vs 19%, p = 0.20), hypertension (43 vs 38%, p = 0.56) or left atrial volume (46.6 vs 39.6 ml, p = 0.10), but patients with previous AF had a lower left ventricular ejection fraction (LVEF) (45.7 vs 52.3%, p = 0.02). In separate, univariate Cox proportional-hazards models only increasing LVEF (Hazard ratio 0.97, 95% confidence interval (0.95; 0.99, p = 0.02)) was associated with a lower risk of incident AF after RAF ablation, but no other risk factor. Conclusions AF occurred in 13.7% of patients early after cavotricuspid isthmus ablation for RAF. There was no difference in the occurrence of AF between patients with and without previously known episodes of AF. Only impaired LVEF was associated with AF occurrence. Abstract Figure

231Local impedance-guided ablation and ultra-high density mapping provide improved ablation metrics vs conventional or contact force-guided ablation for cavotricuspid isthmus dependent atrial flutter

Abstract INTRODUCTION. Radiofrequency ablation (RFA) of cavotricuspid isthmus dependent atrial flutter (CTI-AFL) can be performed with fluoroscopy (Fluo) or 3-dimensional (3D) electroanatomic mapping and contact force (CF) catheters. Local impedance (LI) is an alternative but no comparisons have yet been made. METHODS. An observational study comparing Fluo, CF- and LI-guided RFA for CTI-AFL. In the LI group, if CTI block was not obtained after initial ablation, ultra-high density mapping (UHDm) was used to identify breakthrough sites. Contact was determined using patient specific LI; RF delivered until 20 ohm LI drop seen, or LI drop plateaued &amp;gt;2 secs. In the CF group 10-40g force was used. Power was limited to 40-50W in all groups. Total RFA time, time from RFA start to CTI block, no. of lesions required to achieve block, acute success, complications and re-ablation during follow-up were analysed using ANOVA. RESULTS. Data presented for 24 patients (7 Fluo, 7 CF, 10 LI). Mean RFA time: 6.6, 5.9, 3.2 min respectively (p = 0.0478). Statistically significant differences also seen with LI vs Fluo (p = 0.0451) and LI vs CF (p = 0.0313). Time from first RFA to block: 25.5, 19.8, 14.2 min (p = 0.5688); number of lesions to achieve block: 8.5, 10.3, 8 (p = 0.3909). 100% success and no complications in all groups. 0% need for re-ablation (16.3 ± 7, 12.6 ± 8, 6.5 ± 4.4 months follow-up). DISCUSSION. This data illustrates that UHDm and LI-guidance significantly reduces the amount of CTI RFA, by 52% and 47% vs Fluo and CF respectively (p = sig, fig. 1). A reduction from first RFA to block is also seen (43% and 37%; p = ns, fig. 2). Given no difference in the no. of lesions, LI-guided RFA during lesion formation shortens the duration of each lesion. Many patients require further RFA (+/- mapping) if they do not achieve block following the initial ablation line, resulting in longer procedures. Several patients without block in the LI group underwent repeat UHDm, which quickly identified CTI or epicardial-endocardial breakthrough (fig. 3 &amp; 4), allowing rapid targeting for re-ablation. In the fluo group, these procedures would often be significantly prolonged, meaning extensive RFA and radiation exposure. Fig. 1 shows smaller error bars with LI compared to the others, resulting in more predictable total ablation times; this could potentially benefit procedure scheduling (more procedures per unit time). We could not directly compare overall procedure time as many in the CF group had CTI RFA combined with left atrial RFA. Multiple LI cases were performed fluo-free with only magnetic tracking. This may allow case scheduling without a radiographer, with potential cost savings. CONCLUSION. LI-guided CTI-AFL RFA is safe and effective and has shown favourable ablation metrics compared to Fluo or CF-RFA. LI-RFA with UHDm more quickly and accurately identifies breakthrough and with fluoro-free technique could possibly reduce procedure time and cost. A larger study is planned to provide more insight. Abstract Figures

Efficacy and complications of cavo-tricuspid isthmus-dependent atrial flutter ablation in patients with and without structural heart disease: results from the German Ablation Registry.

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. 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 69years; 78.5% male) and a group without SHD (n= 1362 [38.6%]; 65years; 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 562days 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%). 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.

Significance of fragmented QRS complexes for predicting new-onset atrial fibrillation after cavotricuspid isthmus–dependent atrial flutter ablation

Atrial fibrillation (AF) and cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) are 2 separate entities that coexist in a significant proportion of patients. In patients with CTI ablation of AFL, the decision to hold anticoagulation often becomes an issue. This study aimed to describe the incidence of the development of AF after CTI ablation in patients without a history of AF and to identify the risk predictors of the occurrence of AF. The present study included 120 consecutive patients (106 men; mean age 68 ± 12 years) who underwent radiofrequency catheter ablation (RFCA) of typical AFL since 2010. Patients with a history of AF before RFCA were excluded. The P-wave and QRS morphology, characteristics, and duration were evaluated by 12-lead electrocardiography the day after ablation. During 3.6 ± 2.6 years of follow-up after RFCA, 49 patients (41%) developed new-onset AF. A univariate analysis revealed that the presence of fragmented QRS (fQRS) complexes (hazard ratio [HR], 4.63; 95% confidence interval [CI] 2.31-9.29; P < .001) and advanced interatrial block (IAB), defined as P-wave duration > 120 ms and biphasic morphology in the inferior leads (HR 4.44; 95% CI 2.45-8.01; P < .001), were predictors of new-onset AF. A multivariate analysis revealed that fQRS complexes (HR 3.35; 95% CI 1.58-7.10; P = .002) and advanced IAB (HR 2.64; 95% CI 1.38-5.07; P < .004) were independent predictors. The present study indicated that new-onset AF developed in a significant proportion of patients undergoing AFL ablation. The presence of fQRS complexes and advanced IAB were predictors of new-onset AF.

Supraventricular Tachyarrhythmias in Patients with Ebstein’s Anomaly

The paper analyzes the experience of catheter treatment of various types of supraventricular arrhythmias in patients with Ebstein’s abnormality (EA) – 19 consecutive cases of the elimination of additional atrioventricular connections (AAVC) and 5 cases of atrial macro-reentry. The elimination of AAVC, just like atrial macroreentry, was preceded by a stage of electrophysiological diagnosis. In a series of observations in 19 patients with EA, 25 AAVC were detected. The article reflects the main electrophysiological differences between “wide” AAVC from multiple ones. In the first procedure, the conduction in all AAVC was eliminated in 16 (84.2%) of 19 patients. 6 of 25 AAVC were qualified by us as “wide”; to eliminate them, a larger number of applications was required – 6 ± 2 (in typical cases – 3 ± 1). In 2 of 3 patients with an unsatisfactory result of the first procedure, AAVC were eliminated during the second procedure. In the long-term period(5.6 ± 3.6 years), recurrences of propagation through AAVC occurred in 2 (10.5%) of 19 patients. All AAVC were permanently eliminated during second procedure. In the group of patients with atrial tachycardia, 3 had a graph characteristic of a typical isthmus-dependent atrial flutter. In one patient with atypical graphics, macro-reentry with excitation circulation around the scar on the anterolateral wall of the right atrium was found. In 3 of 4 patients with isthmus-dependent atrial flutter after radiofrequency exposure, the sinus rhythm was restored and a block of passage through the cavotricuspid isthmus was created. In one case there were changes in the cycle of tachycardia and the morphology of wave P, applying applications between the scar and the tricuspid valve ring led to the creation of a block of passage through this area and to the cessation of arrhythmia. In a patient who initially had reentry with a circulation of excitement around the postoperative scar, arrhythmia was eliminated in a similar way (an additional block was created through the cavotricuspid isthmus). In the observation period of 5.2 ± 2.5 years, there were no recurrences of arrhythmia.

P3673Electroanatomical mapping of right atrium in patients with pulmonary hypertension

Abstract Introduction Atrial fibrillation (AF) and related atrial tachycardia (AT), including cavotricuspid isthmus dependent atrial flutter (AFL), are a known complication of pulmonary hypertension (PH). Catheter ablation is an established method of treatment of selected patients with heart rhythm disorders. The aim of the work was to evaluate arrhythmogenic substrate in the right atrium (RA) of the group of patients who underwent catheter ablation with electroanatomical mapping. Methods The findings in electroanatomical mapping with contact force of RA were evaluated in a group of 22 patients (16 men, median and scattering age 73, range 45–87 years) indicated for catheterization ablation for AFL or other right-sided AT. During electroanatomical mapping, 8 patients had sinus rhythm and 14 patients had AF or AT (all AT with cycle length under 350 ms). Areas with reduced atrial electrogram voltages (AEGM) &lt;0.1 mV in sinus rhythm or &lt;0.04 in AF or AT, existence of double and fragmented potentials were identified. Results Out of the 22 patients, 3 patients had hypoxic PH, 13 individuals had chronic thromboembolic PH (7 undergoing surgical treatment) 4 patients had idiopathic PH and 2 patients had combined PH. The median mean pulmonary arterial pressure was 44 (range 22 - 72) mmHg. The median RA CARTO volume was 225 (range 151–383) ml. Out of all patients, 2 subjects manifested scattering of the surface proportion RA with a defined reduced voltage over 10% (maximum 15%). Six subjects had surface proportion with defined reduced voltage in interval 1–9% and 14 subjects had scattering below 1% of total surface area of RA. The predominant localizations of pathological AEGMs was the area adjacent to the vena cava superior and posterior portion of RA between caval veins. Regular finding in patients following surgical treatment of thromboembolic PH was a scar after atriotomy. Arrhythmogenic substrate in right atrium Conclusion Dilatation of RA is present in all PH patients. However, the proportion of tissue with reduced AEGM voltage in RA does not appear to be extensively high in this population.

Predictors and Incidence of Atrial Flutter After Catheter Ablation of Atrial Fibrillation

Atrial flutter (AFL) is a common form of arrhythmia recurrence after atrial fibrillation (AF) ablation. We aimed to define (1) the incidence of AFL and (2) the clinical factors associated with cavo-tricuspid isthmus dependent (typical) and atypical AFL, after AF ablation. The retrospective cohort consisted of 1,029 patients that underwent initial radiofrequency AF ablation from May 2005 to December 2013 at a single academic center. Patients with missing follow-up data, history of AFL ablation, and those with undocumented AFL were excluded. Atrial volumes were measured using three-dimensional cardiac computed tomography or magnetic resonance imaging. A total of 607 patients were included in the final cohort (age 59.2 ± 10.6 years, 76.0% men, 58.7% paroxysmal AF). During a median follow-up of 845 days (interquartile range 389 to 1,597 days), 122 (20.1%) patients developed AFL. Of these, 17 had typical AFL, 98 had atypical AFL, and 7 patients had both circuits. In the multivariable Cox regression analysis, only right atrial volume index (hazard ratio [HR] 1.25 per 10 ml/m2, confidence interval [CI] 95% 1.10 to 1.42) was associated with incident typical AFL; whereas persistent AF (HR 1.59, CI 95% 1.06 to 2.40), linear lesions (HR 1.58, CI 95% 1.02 to 2.46) and left atrial volume index (HR 1.17 per 10 ml/m2, CI 95% 1.07 to 1.27) were associated with incident atypical AFL. In conclusion, noninvasive measures of right and left atrial remodeling are strongly associated with incident AFL after AF ablation. Strategies to prevent incident AFL using these measures after index ablation warrant further investigation.

Different characteristics of postoperative atrial tachyarrhythmias between congenital and non-congenital heart disease.

The chance of encountering tachyarrhythmias has been increasing in adult congenital heart disease (CHD) patients with previous open-heart surgery, along with the improvement of their longevity. However, the characteristics of these arrhythmias remain to be elucidated. We examined the characteristics of atrial tachyarrhythmias (ATs) in 26 consecutive CHD patients (M/F 17/9) referred for catheter ablation and compared them with 16 non-CHD patients with cardiac surgery (M/F 11/5). The CHD group was younger and had a longer period from cardiac surgery until the occurrence of ATs compared with the non-CHD group (44.8 ± 19.5 vs. 67.6 ± 12.5years old, and 23.3 ± 13.2 vs. 6.3 ± 4.9years, respectively, both P < 0.05). Multiple ATs were equally induced in both groups, 12 in CHD (46.1%) and 5 in non-CHD (31.3%). Although the prevalence of macro-reentrant ATs (cavo-tricuspid isthmus-dependent atrial flutter (AFL) or intra-atrial reentrant tachycardia (IART)) was comparable, the mechanisms were different between the 2 groups (AFL and IART), 34% and 27% in CHD and 71% and 24% in non-CHD, respectively. Furthermore, focal AT (FAT) was noted in 9 patients (34.6%) in CHD but none in non-CHD (P < 0.05). Electroanatomical mapping showed that the surface area and low-voltage area (LVA) of the right atrium were significantly larger in CHD than in non-CHD (197.1 ± 56.4 vs. 132.4 ± 41.2cm2, and 40.8 ± 33.3 vs. 13.6 ± 9.0cm2, respectively, both P < 0.05). Ten out of 14 FATs (71.4%) were highly associated with LVA, especially near the crista terminalis. The development of ATs in CHD patients could be associated with large atrial remodeling, resulting in complicated ATs.

Atrial Tachyarrhythmias and Atrial Flutter: the Basics of Diagnostics and Modern Opportunities of Therapy

The article is devoted to the description of all types of atrial tachyarrhythmias, including inappropriate sinus tachycardia, which, as a rule, is not paid enough attention in the domestic literature, sinoatrial node reentrant tachycardia, focal and multifocal atrial tachycardia, atrial flutter, and atrial fibrillation. The electrophysiological mechanisms of development and electrocardiographic criteria for the diagnosis of these cardiac rhythm disturbances are presented. Along with this, the article discusses the modern view of the strategy and tactics of pharmacological cardioversion and preventive therapy in patients with the main types of atrial tachyarrhythmias and atrial flutter. It is noted that the prognosis for inappropriate sinus tachycardia, as a rule, is favorable, and therefore, aim of treatment is to reduce the symptoms, and in their absence medical treatment is not necessary. Much attention is paid to drug and interventional treatment of atrial flutter. It is emphasized that catheter ablation of isthmus-dependent atrial flutter in most cases is preferred over long-term pharmacotherapy. However, in prolonged observation (more than 3 years), nearly 1/3 of patients may develop paroxysmal atrial fibrillation. At the same time, catheter ablation of atypical atrial flutter is, in most cases, substantially less effective. The indications and side effects of catheter ablation of the sinus node are also discussed. The authors provide a critical analysis of traditional approaches to the treatment of atrial tachyarrhythmias and analyze new recommendations for the management of these patients presented in Europe and the USA. Based on these recommendations, clear algorithms for the management of patients with atrial tachyarrhythmias are given. The need to prevent thromboembolic complications in some types of atrial tachyarrhythmias is emphasized.

Atrial fibrillation inducibility during cavo-tricuspid isthmus dependent atrial flutter ablation for the prediction of clinical atrial fibrillation

BackgroundAtrial fibrillation (AF) and cavo-tricuspid isthmus (CTI) dependent atrial flutter (AFL) are two separate entities that coexist in a significant percentage of patients. MethodsWe sought to investigate whether AF inducibility during CTI AFL ablation predicted the occurrence of AF at follow up after AFL ablation. Univariate and multivariate analyses were performed. ResultsA total of 154 patients (male: 72%, age: 61±13) with AFL and without history of AF were included. All patients underwent successful CTI dependent AFL ablation demonstrated by bidirectional block. During ablation, AF was seen or induced in 28 (18%) patients. After a mean follow up of 34±24months a total of 50 patients (32%) were noted with clinically manifest AF. From the patients who had inducible AF during AFL ablation, 50% developed post-procedural AF. From those in whom AF could not be induced, only 29% were documented with AF after ablation. Univariate and multivariate analyses revealed that only age and AF inducibility during AFL ablation were predictors of AF. Univariate analysis (age p=0.038 and inducible AF p=0.032 with odds ratio of 1.030 [95% CI (1.002–1.059)] and 2.500 [95% CI (1.084–5.765)], respectively) and multivariate analyses (age p=0.011 and inducible AF p=0.016 with adjusted odds ratio of 1.043 [95% CI (1.010–1.077)] and 3.293 [95% CI (1.250–8.676)], respectively). ConclusionAF inducibility in patients undergoing CTI AFL without history of AF is a strong predictor of AF occurrence in the future. Appropriate cardiology follow-up must be encouraged in this high-risk population as stroke prevention strategies can be appropriately introduced in a timely matter especially in patients with elevated CHA2DS2-VASc scores (≥2).

Use of adenosine to shorten the post ablation waiting period for cavotricuspid isthmus-dependent atrial flutter.

Dormant conduction unmasked by adenosine predicts clinical recurrences of cavotricuspid isthmus (CTI) dependent atrial flutter following catheter ablation. Conventional practice involves a waiting period of 20 to 30 minutes after achievement of a bidirectional line of block (BDB) to monitor for recovery of conduction. Assess whether abolition of dormant conduction with adenosine immediately after CTI ablation and BDB can predict the lack of CTI conduction recovery during the following 30 minutes. Consecutive patients undergoing catheter ablation for CTI-dependent atrial flutter were studied. Following the completion of CTI ablation and documentation of BDB, adenosine (≥12 mg IV) was administered immediately. In cases of dormant conduction, the CTI was ablated again until its abolition. After the achievement of BDB without dormant conduction, spontaneous CTI reconnection during the following 30 minutes and dormant conduction with adenosine at 30 minutes were evaluated. A CTI block was achieved in 171 patients. Nine patients (5.3%) had dormant conduction across the CTI immediately after ablation and BDB, and required further ablation. Two patients (1.2%) had subsequent spontaneous time-dependent reconnection within 30 minutes. Two other patients (1.2%) developed late dormant conduction with adenosine at 30 minutes. All 4 patients underwent further ablation. A negative adenosine challenge immediately after CTI ablation with bidirectional block, or after abolition of dormant conduction with further ablation, strongly predicted the absence of subsequent spontaneous reconnection within 30 minutes. Based on these results, the conventional waiting period is unnecessary in 97.6% patients without dormant conduction after CTI-dependent flutter ablation.

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.

Predictors of acute inefficacy and the radiofrequency energy time required for cavotricuspid isthmus-dependent atrial flutter ablation.

Although cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) ablation is a highly efficacious treatment, a bidirectional CTI block cannot be achieved in some patients. In this study, we sought to determine the predictors of acute inefficacy of CTI-AFL ablation and the predictors of the radiofrequency (RF) energy time required to achieve a complete bidirectional CTI block. All consecutive patients who underwent stand-alone CTI-AFL ablation in our institution, except patients with congenital heart disease, were included in this retrospective study. Clinical, echocardiographic, and ablation data were collected from the Arrhythmia Unit and Imaging Unit databases and medical charts. Three hundred and fifty-five patients, with a mean age 63 ± 12years, were included. The ablation was acutely inefficacious in 30 patients (9%). Tricuspid regurgitation was the only independent predictor of acute inefficacy of CTI-AFL ablation (OR 3.161, 95% CI 1.084-9.220, p = 0.035) and was associated with a longer RF time required to achieve CTI bidirectional block (p = 0.031). Age was inversely correlated with the RF time required to achieve a bidirectional CTI block (r = -0.133, p = 0.025). A previous CTI RF ablation, chronic obstructive pulmonary disease (COPD), the use of an irrigated catheter, and advanced age were the independent predictors for requiring less RF energy time to achieve a bidirectional CTI block. Tricuspid regurgitation is associated with less acute efficacy in CTI-AFL ablation. Prior CTI ablation, COPD, use of an irrigated catheter, and advanced age are independent predictors for needing less RF energy time to achieve a complete bidirectional CTI block.