Cavotricuspid Isthmus-dependent Atrial Flutter Research Articles

Prospective Evaluation of a Standardized Screening for Atrial Fibrillation after Ablation of Cavotricuspid Isthmus Dependent Atrial Flutter.

Aims: We aimed to prospectively investigate the effectiveness of a standardized follow-up for AF-detection after common atrial flutter (cAFL) ablation. Methods: A total of 309 patients after cAFL ablation without known AF, from 5 centers, and at least one completed, standardized follow-up at 3, 6 and 12 months, including a 24 h Holter-electrocardiogram (ECG), were included. The primary outcome was incident atrial fibrillation (AF), or atrial tachycardia (AT). Predictors were investigated by Cox proportional-hazards models. Results: The mean age was 67.9 years; 15.2% were female and the mean CHA2DS2-VASc (Congestive heart failure, Hypertension, Age, Diabetes, Stroke, Vascular disease, Sex category) score was 2.4 points. The great majority of patients (90.3%) were anticoagulated. Over a mean follow-up of 12.2 months with a standardized approach, AF/AT was detected in 73 patients, corresponding to 11.7% at 3 months, 18.4% at 6 months and 28.2% at 12 months of follow-up. AF was found in 64 patients, AT in 9 and both in 2 patients. Occurrence of AF was recorded in 40 (60.6%) patients by Holter-ECG and in the remaining 26 (39.4%) by clinical follow-up only. There was no difference in male versus female (p = 0.08), or in younger versus older patients (p = 0.96) for AF/AT detection. Only coronary artery disease (hazard ratio [95% confidence intervals] 1.03 [1.01–1.05], p = 0.01) was associated with the primary outcome. Conclusions: AF or AT was detected in a large proportion of cAFL patients after cavotricuspid-isthmus (CTI) ablation, using a standardized follow-up over 1 year. This standardized screening can be easily implemented with high patient acceptance. The high proportion of post-ablation AF needs to be taken into consideration when deciding on long-term oral anticoagulation.

B-PO04-108 FIRST IN CLINICAL ROUTINE ISTHMUS-DEPENDENT ATRIAL FLUTTER ABLATION ENTIRELY PERFORMED IN THE INTERVENTIONAL MRI SUITE USING ACTIVE CATHETER IMAGING

Recently, magnetic resonance imaging (MRI) has been established as a radiation-free alternative to fluoroscopy to image anatomy and structural alterations causative for arrhythmogenesis during cavotricuspid isthmus (CTI) dependent atrial flutter (AFl) ablation procedures. Describe the first real-world experience of CTI ablations performed completely in the interventional cardiac magnetic resonance (iCMR) suite using active catheter imaging. Fifteen patients (73% male, median age 70 yrs (IQR 67-82) underwent ablations in the iCMR suite. Procedures were performed in a 1.5T MRI with MR-conditional ablation catheters. Catheter guidance was performed using active catheter imaging leveraging MR receive coils within the catheter tip [Figure]. Ablation success, complications, and time for procedure were collected. All 15 patients achieved acute procedure success without complication. Median procedure time was 43min (IQR 33-58) with an RF delivery time of 18 min (interquartile range (IQR) 12-26). Post-procedure lesion visualization scanning was 32 min (IQR 10-42). In 5 patients left ventricular ejection fraction improved from 28±7 % to 47±6% after ablation. Of the13 patients that made it to 6 month follow up (1 lost to follow up, 1 death at 6 months), none of the patients had AFl recurrence. CTI-dependent AFl ablation using active catheter imaging can successfully be performed entirely in the iCMR suite. The MR environment allows anatomic visualization of the CTI, intra-procedural lesion visualization, and exclusion of a pericardial effusion.

B-PO02-076 LONG-TERM CARDIOVASCULAR OUTCOME OF PATIENTS WITH ATRIAL FLUTTER UNDERGOING CATHETER ABLATION

The data regarding the long-term efficacy of cavotricuspid isthmus (CTI) dependent atrial flutter (AFL) ablation in terms of mortality and cardiovascular risk in AFL patients without AF history was still unclear. To determine the effectiveness of catheter ablation compared to conventional medical therapy for improving cardiovascular outcomes among patients with solitary AFL. We collected the data of 3,784 patients who were diagnosed with AFL without history of AF. After propensity matching for age, sex, comorbidities, and medications, we analyzed the outcome of total deaths, cardiac deaths, heart failure (HF), and AF admissions. Survival curve analysis showed that patients who had AFL ablation had a significantly better outcome in terms of total deaths, cardiovascular deaths, HF admissions, and AF admissions compared to medically treated patients (Figure). After adjusted with confounding factors, we identified that AFL ablation and future AF ablation reduced the risk for total deaths (HR: 0.68; 95% CI: 0.62-0.74, p< 0.001), cardiac deaths (HR: 0.78; 95% CI: 0.67-0.91, p=0.001), HF (HR 0.84; 95%: CI, 0.75-0.95, p=0.01), and AF admissions (HR 0.83; 95% CI 0.76-0.92, p<0.001). In patients who only received AFL ablation, we still found risk reduction of total death (HR: 0.65; 95% CI: 0.58-0.72, p<0.001), cardiac death (HR: 0.77; 95% CI: 0.64-0.92, p=0.003), and HF admissions (HR: 0.83; 95% CI: 0.72-0.96, p=0.01). AFL catheter ablation reduces the risk of total deaths, cardiac deaths, stroke admissions, HF admissions, and AF admissions in AFL patients without history of AF during a very long-term follow up.

Radiofrequency Catheter Ablation of Supraventricular Tachycardia in Patients With Pulmonary Hypertension: Feasibility and Long-Term Outcome.

BackgroundSupraventricular tachycardia (SVT) occurs commonly and is strongly correlated with clinical deterioration in patients with pulmonary hypertension (PH). This study aimed to investigate the feasibility and long-term outcome of radiofrequency catheter ablation (RFCA) in PH patients with SVT.Materials and MethodsConsecutive PH patients with SVT who were scheduled to undergo electrophysiological study and RFCA between September 2010 and July 2019 were included. The acute results and long-term success of RFCA were assessed after the procedure.ResultsIn total, 71 PH patients with 76 episodes of SVT were analyzed. Cavotricuspid isthmus-dependent atrial flutter (n = 33, 43.5%) was the most common SVT type, followed by atrioventricular nodal reentrant tachycardia (n = 16, 21.1%). Of the 71 patients, 60 (84.5%) underwent successful electrophysiological study and were subsequently treated by RFCA. Among them, acute sinus rhythm was restored in 54 (90.0%) patients, and procedure-related complications were observed in 4 (6.7%) patients. Univariate logistic regression analysis showed that cavotricuspid isthmus-independent atrial flutter [odds ratio (OR) 25.00, 95% confidence interval (CI) 3.45–180.98, p = 0.001] and wider pulmonary artery diameter (OR 1.19, 95% CI 1.03–1.38; p = 0.016) were associated with RFCA failure. During a median follow-up of 36 (range, 3–108) months, 7 patients with atrial flutter experienced recurrence, yielding a 78.3% 3-year success rate for RFCA treatment.ConclusionThe findings suggest that RFCA of SVT in PH patients is feasible and has a good long-term success rate. Cavotricuspid isthmus-independent atrial flutter and a wider PAD could increase the risk for ablation failure.

Benefits of catheter ablation of typical cavotricuspid isthmus-dependent atrial flutter using half-normal saline

Abstract Funding Acknowledgements Type of funding sources: None. Background Radiofrequency catheter ablation (RFA) of cavotricuspid isthmus–dependent atrial flutter (AFL) is a procedure with a high success rate and a low complication rate. The anatomical variation and irregularity of the isthmus, with the high local blood flow, can reduce the effectiveness of the lesion and consequently of the procedure. Recent data suggests that deeper ablation lesions can be created using open-irrigated catheters (CA) with half-normal saline (HNS). Purpose To assess the acute efficacy and safety of RFA of AFL with half-normal saline (HNS). Compare the results with CA irrigated with normal saline (NS). Methods Randomized, prospective, observational and single-center study. Consecutive patients with first AFL RFA between June 2019 and December 2020 were included. CA with HNS or NS were used, with a limit of 40 watts and 40° C. An RFA line was performed under fluoroscopic guidance or electroanatomic mapping. If necessary, the lesion was repeated until the arrhythmia was interrupted and the bidirectional block was achieved (success). Acute success, total radiofrequency time (RT), number of radiofrequency applications, and complications were analyzed. Results 38 patients with RFA of AFL were analyzed. 19 in the HNS and 19 in the NS group. There were no significant differences between the baseline characteristics of each group. (Table 1) The accute success rate was 100% with a median of 2 RFA applications in both groups. The mean RT in HNS was 7:10 vs 09:16 min in NS group; the t-test analysis did not show a significant difference (p = .2). A subanalysis was performed in those patients who required more than 2 lines of RFA; a mean of 4 in the HNS group vs 6 in the NS group (p = .4). In the HNS group, RT was significantly shorter; 8:17 vs 13:17 min in the NS group (p = .011). (Figure 1) There was a steam pop in the HNS group and no complications or steam pop in the NS group (p = .53). Conclusions RFA of AFL using HNS is an effective and safe procedure. In patients with unfavorable anatomy who required a greater number of applications, the radiofrequency time was significantly shorter using HNS. Baseline characteristicsHNS (19 p)NS(19 p)pAge56 ± 12.3 years61 ± 10.8 years.22Male16 p (84%)16 p (84%)1Heart Disease7 p (36.8%)5 p (26.3%).68Ejection Fraction57.1 ± 11%56 ± 14.3%.49Ejection Fraction &amp;lt; 50%2 p (10.5%)2 p (10.5%)1Electroanatomic mapping10 p (52.6%)8 p (42.1%).7Abstract Figure. Fugure 1

Immuno-Electrophysiological Mechanisms of Functional Electrical Connections Between Recipient and Donor Heart in Patients With Orthotopic Heart Transplantation Presenting With Atrial Arrhythmias.

[Figure: see text].

Barlow syndrome and postoperative cavotricuspid isthmus-dependent atrial flutter – therapeutic modality

Barlow syndrome and postoperative cavotricuspid isthmus-dependent atrial flutter – therapeutic modality

Radiofrequency ablation of supraventricular arrhythmias after orthotopic heart transplantation: Long-term follow-up of a single-center experience.

Supraventricular arrhythmias (SVAs), commonly managed with radiofrequency ablation (RFA), may occur after orthotopic heart transplantation (OHT). We retrospectively assessed 514 consecutive patients (pts.) undergoing OHT between January 1990 and July 2016 in a single-center. Patients with SVAs managed with RFA were included. Mechanisms of genesis of SVAs, association with surgical techniques and outcomes, were analyzed. Of 514 pts undergoing OHT, 53% (272 pts.) were managed with bicaval (BC) technique and 47% (242 pts.) with biatrial (BA) technique. Mean follow-up 10±8.4years. Nine pts. (1.7%) developed SVA requiring RFA. The BC technique was performed in 4 pts., 3 pts. presented cavotricuspid isthmus-dependent atrial flutter (CTI AFL), and 1 pt. double loop AFL. Five pts. were managed with BA technique, 4 pts. presented CTI AFL, and 1 pt. atrial tachycardia (AT). Mean time between OHT and SVA occurrence was 6.6±5.5years. The procedure was successful in 89% (8 pts.). Arrhythmia recurrence was seen in 3 pts (37%), all with BA technique. Supraventricular arrhythmias in heart transplantation may be associated with the surgical scar. Identifying the mechanism is vital to choose the appropriate treatment with radiofrequency ablation.

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.

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.

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.

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.

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.

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.

Long-term outcomes in patients with ablation of clockwise and counterclockwise forms of typical atrial flutter

The atrial flutter of common type, with more frequent typical counterclockwise form, may occasionally present with clockwise form. The latter might be induced by clockwise functional block within cavotricuspid isthmus (CTI) of a premature atrial complex originating from the right atrium. As physiopathology might differ, we sought to compare long-term outcomes in patients who underwent CTI radiofrequency ablation for atrial flutter according to the electrical activation (clockwise or counterclockwise) at baseline. All patients who underwent CTI radiofrequency ablation between 2000 and 2010 in the cardiology department of a four-hospital institution were included for analysis. Association with atrial fibrillation (supposed to be more frequently seen in case of left atrial origin of the arrhythmia), all-cause mortality, thromboembolic events, and atrial fibrillation occurrence were compared between patients with clockwise (group A) and counterclockwise (group B) CTI-dependant flutter. There was no significant difference at baseline (age, sex, heart failure, medication, hypertension, diabetes and stroke) between patients in group A ( n = 41) and B ( n = 831). Concomitant atrial fibrillation (AF) was present in 43% of patients in group A and 37% of patients in group B ( P = 0.39). Deaths ( n = 38), stroke/thromboembolic events ( n = 30) and evolution to permanent AF ( n = 53) were recorded after a follow-up of 826 ± 1024 days. There was no significant difference between both groups for occurrence of death of any cause (hazard ratio 1.31, 95%CI 0.53–3.23 in group A compared to group B, P = 0.55), stroke and thromboembolic events (hazard ratio 2.17, 95%CI 0.65–7.14, P = 0.20) and evolution to permanent AF (hazard ratio 2.27, 95%CI 0.78–6.25, P = 0.13). Despite very different prevalence rates, clockwise and counterclockwise forms of CTI dependent atrial flutter occur in similar populations and seem associated with relatively similar outcomes.

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.