Catheter Ablation Of Atrial Tachycardia Research Articles

Successful catheter ablation of atrial tachycardia initiated with orthodromic capture of superior vena cava potentials.

Acase of successful catheter ablation of paroxysmal atrial fibrillation and atrial tachycardia is reported. After pulmonary vein isolation, atrial tachycardia was induced by the use of isoproterenol and burst pacing from the catheter in the right atrium. An attempt was made to create athree-dimensional (3D) map of the atrial tachycardia, but the atrial tachycardia was terminated in the middle of the mapping. The 3D map was insufficient but indicated that the superior vena cava was involved in the circuit. When the intracardiac electrograms were reviewed, it was found that the atrial tachycardia was initiated with orthodromic capture of superior vena cava potentials and it was considered that the atrial tachycardia involved the superior vena cava-right atrium junction. Accordingly, superior vena cava isolation was performed. After that, atrial fibrillation and atrial tachycardias were not induced by the use of isoproterenol and burst pacing. In this case, an intracardiac electrogram at the time of induction of the tachycardia was helpful for understanding the circuit of the tachycardia.

Remote magnetic navigation catheter ablation for atrial tachycardia in a patient with d-transposition of the great arteries, atrial switch and a mechanical valve in the tricuspid position.

Remote magnetic navigation catheter ablation for atrial tachycardia in a patient with d-transposition of the great arteries, atrial switch and a mechanical valve in the tricuspid position.

Electrophysiologic mechanism and ablation strategy for macroreentrant biatrial tachycardias after Cox-maze procedures

BackgroundDifferent types of recurrent atrial tachycardia (AT) after Cox-maze procedures have been reported, whereas biatrial tachycardia (BiAT) has not been systematically analyzed. ObjectiveIn this study, we retrospectively investigated the electrophysiologic characteristics of BiAT after Cox-maze procedures by use of an ultrahigh-density mapping system. MethodsOf a consecutive 76 patients who underwent catheter ablation of AT after Cox-maze procedures, 12 BiATs were identified. High-density activation mapping was performed in both the left atrium and right atrium in combination with entrainment pacing to confirm the circuit. ResultsWe classified these BiATs into 2 groups. In group 1 (7 patients), the bidirectional block of maze linear lesions to prevent the macroreentrant AT was achieved; the posterior interatrial connections were involved in the circuit. In group 2 (5 patients), the bidirectional block of maze linear lesions was not blocked, and the most common gap was located at the end of the linear lesion near the annulus. In group 1, all the ATs were terminated by targeting the corresponding left atrium end of the posterior interatrial connections. In group 2, the ATs were terminated by targeting the gap near the annulus. ConclusionThe optimal ablation strategy for BiATs after the maze procedure should be based on detailed demonstration of the circuit by high-density mapping.

Prognostic implications of baseline rhythm during catheter ablation for atrial tachycardia.

Atrial tachycardias (AT) occurring in patients after previous atrial fibrillation (AF) ablation are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The purpose of this study was to assess procedural and clinical outcome depending on baseline rhythm at the beginning of AT ablation. A total of 380 patients (69 (61-75) years, 56.6% male) who underwent catheter ablation for consecutive AT after previous AF ablation were studied. At the beginning of the procedure, 140 patients (36.8%) presented in sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF. Patients in SR or with AT underwent shorter procedures (173 (132-213) minutes vs. 161 (120-203) minutes vs. 226 (154-249) minutes; p = 0.002) with more frequent termination to SR (87.9% vs. 81.3% vs. 56.3%; p < 0.001) than patients with AF. Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (96.4% vs. 97.1% vs. 87.5%; p = 0.033). During a follow-up of 290 (181-680) days, patients in baseline SR experienced arrhythmia recurrences less often (36.4% vs. 49.5% vs. 68.8%; p = 0.002) than patients with AT or AF. Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favorable mid-term success rate.

Baseline rhythm during catheter ablation for atrial tachycardia predicts procedural and clinical outcome

Abstract Funding Acknowledgements Type of funding sources: None. Background Atrial tachycardias (AT) occurring after previous ablation in patients with a history of atrial fibrillation (AF) are increasingly observed in clinical practice. Catheter ablation is the treatment of choice but an optimal workflow to improve patient outcome has not been defined. The prognostic implications of baseline rhythm at the beginning of AT ablation are unknown. Purpose The aim of this study was to assess procedural and clinical outcome depending on baseline rhythm during AT ablation. Methods A total of 380 patients with a history of AF who underwent catheter ablation for consecutive AT after previous ablation were analysed. Results In our study population (69 (61–75) years, 56.6% male), 140 patients (36.8%) presented in baseline sinus rhythm (SR), 208 (54.7%) with AT and 32 (8.4%) with AF at the beginning of the procedure. Patients in SR or with AT underwent shorter procedures (SR: 173 (132–213) minutes vs. AT: 161 (120–203) minutes vs. AF: 226 (154–249) minutes; P=0.002) with more frequent termination to SR (SR: 87.9% vs. AT: 81.3% vs. AF: 56.3%; P&amp;lt;0.001) than patients with AF. Periprocedural AT cycle length was longer in patients presenting in SR than in those with AT or AF (SR: 320 (265–370) ms vs. AT: 270 (240–310) ms vs. AF: 245 (193–278) ms; P&amp;lt;0.001). Acute procedural success did not differ between patients in SR or with AT but was higher compared to those with AF (SR: 96.4% vs. AT: 97.1% vs. AF: 87.5%; P=0.033). During a median follow-up of 290 (181–680) days, patients in baseline SR developed arrhythmia recurrences less often (SR: 36.4% vs. AT: 49.5% vs. AF: 68.8%; P=0.002) compared to patients with AT or AF. Conclusions Baseline rhythm during AT ablation predicts procedural and clinical outcome. Whereas acute procedural success does not differ between patients in SR or with AT, patients presenting in SR have a more favourable mid-term success rate. Restoration of SR prior to ablation might improve long-term outcome by reducing the risk for recurrent arrhythmia.

Automated three-dimensional activation versus conventional mapping for catheter ablation of atrial tachycardia – A prospective randomized trial

BackgroundThe automated NavX Ensite Precision latency-map (LM) algorithm aims to identify atrial tachycardia (AT) mechanisms. However, data on a direct comparison of this algorithm with conventional mapping are scarce. MethodsPatients scheduled for AT ablation were randomized to mapping with the LM- algorithm (LM group) or to conventional mapping (conventional only group: ConvO), using entrainment and local activation mapping techniques. Several outcomes were exploratively analyzed. Primary endpoint was intraprocedural AT Termination. If AT termination with only automated 3D-Mapping failed, additional conventional methods were applied (conversion). ResultsA total of 63 patients (mean 67 years, 34 % female) were enrolled. In the LM group (n = 31), the correct AT mechanism was identified in14 patients (45 %) using the algorithm alone compared to 30 patients (94 %) with conventional methods. Time to termination of the first AT was not different between groups (LM group 34 ± 20 vs. ConvO 43.1 ± 28.3 min; p = 0.2). However, when AT termination did not occur with LM algorithm, time to termination prolonged significantly (65 ± 35 min; p = 0.01). After applying conventional methods (conversion), procedural termination rates did not differ between LM group (90 %) vs. ConvO (94 %) (p = 0.3). During a follow-up time of 20 ± 9 months, no differences were observed in clinical outcomes. ConclusionIn this small prospective, randomized study, theuse of the LM algorithm alone may lead to AT termination, but less accurate than conventional methods.

Non-invasive electrocardiographic imaging for the characterization of complex atrial tachyarrhythmias

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This work was supported by the European Union NextGenerationEU/PRTR. Background – The non-invasive characterization of complex atrial tachyarrhythmias, including atrial flutter (AFL) and focal atrial tachycardia (AT) is challenging. Conventional 12-lead electrocardiogram (ECG) faces several limitations. Planning a precise and preprocedural strategy for complex tachyarrhythmias catheter ablation (CA) is not easy. Purpose To evaluate the diagnostic capacity of a novel electrocardiographic imaging (ECGI) system that does not require previous CT/MRI thoracic imaging. Methods – 42 patients (27 males, CHA2DS2-VASc score 2±1, LVEF 54.5 ± 11.0 % and LA area 31.3 ± 7.0 cm2) undergoing CA for focal AT or AFL were prospectively included in the study. A preprocedural ECGI was managed based on a 64-electrode vest, a torso reconstruction using a 3D real-time acquisition camera, and an artificial intelligence-based method to estimate the patient atrial geometry. The differential diagnostic capacities of non-invasive 12-lead ECG and ECGI were assessed compared with endocavity electroanatomical mapping (EAM) regarding three endpoints: 1) the identification of the involved atrial cavity, 2) the mechanism (focal/micro-reentry or macro-reentry), and (3) the ablation target site defined as the area where the earliest activation was located for focal/micro re-entrant arrhythmias, and the precise anatomical pathway for macro re-entrant tachyarrhythmias. Regarding the ECG, the three endpoints were assessed based on validated algorithms by 2 different observers blinded from the diagnosis. Results – 48 atrial tachyarrhythmias of which 59.5% occurred in the context of a history of CA were evaluated. The non-invasive characterization of complex atrial arrhythmias using this novel ECGI system was possible in 94% of the cases (Figure A): directly for 36 arrhythmias and after decreasing ventricular response using vagal maneuvers for 9. ECGI obtained global accuracy to identify the involved atrial cavity of 91.7%, the mechanism of 89.6%, and the ablation target of 83.3%. In challenging cases, such as in patients with history of CA for AF (n = 27) and in patients without a final diagnosis of counterclockwise typical AFL (n=38) the diagnosis capacity of ECGI is consistent compared to the whole study population. The ECGI diagnostic capacity significantly outclassed the ECG one regarding the identification of the involved cavity (p&amp;lt;0.001), the mechanism (p&amp;lt;0.05), and the ablation target (p&amp;lt;0.001). ECGI was able to prevent the totality of unnecessary transseptal punctures (n=7), representing 28% of the overall punctures. Conclusions (Figure B) – This novel non-invasive ECGI system that does not require CT/MRI thoracic imaging accurately characterizes complex atrial tachyarrhythmia and outclasses ECG, the current noninvasive diagnostic tool of reference.

PE-452787-3 INITIAL EXPERIENCE OF PULSED FIELD ABLATION OF ATRIAL FIBRILLATION AND ATRIAL TACHYCARDIA IN ADULT PATIENTS WITH CONGENITAL HEART DISEASE

Prevalence of atrial tachycardias (AT) and atrial fibrillation (AF) is increasing in adult patients with congenital heart disease (CHD) significantly contributing to morbidity. Catheter ablation of AT and AF in the adult CHD population is challenging and recurrence is significant. Pulsed field ablation (PFA) is a new, non-thermal energy source for catheter ablation of AF. Due to its inherent properties of creating effective ablation lesions without permanent affection of non-myocardial tissue, it is attractive for the use in the adult CHD population. To date, its use in the adult CHD population has not been reported. This study describes initial experience of PFA of AT and AF in adult CHD patients. Prospective enrollment of adult CHD patients with a history of recurrent AT/AF, who had prior radiofrequency (RFA)/cryoenergy (Cryo) ablation of AT/AF. A high-density map using a 3D mapping system (EnSite™ Precision; Abbott) in conjunction with a high-density catheter (Advisor™ HD Grid; Abbott) was performed prior and after PFA. PFA was performed using the FARAWAVE™ ablation catheter (Boston Scientific) and applying repeated 2 kV pulses (2.5 s each) to the respective substrate. Procedural success was defined as complete substrate ablation (residual atrial electrograms < 0.05 mV on voltage map). Four adult CHD patients with recurrent AT/AF despite repeated previous RFA/cryoablation were enrolled. 2/4 had interrupted inferior V. cava and a transhepatic access was used to get access to the left atrium. PFA of all pulmonary vein ostia and the left atrial posterior wall was performed in 3 subjects. Additional PFA of a septal low voltage area was achieved in one of these patients. In the fourth patient with Ebstein’s anomaly, PFA of the cavotricuspid isthmus (CTI) and of a conduction gap within the crista terminalis was performed. Complete procedural success was achieved in all patients. Transient, fully reversible spasm of the right coronary artery without ECG changes occurred after PFA within the CTI. No recurrence of AT/AF was observed during follow-up of 5 months. Herein, we report for the first time the use of PFA in adult CHD patients with recurrent AT/AF. PFA turned out to be effective and generally safe. When using it in proximity to the coronary arteries, one must be aware of reversible coronary artery spasm. PFA might be a valuable tool to improve mid- and long-term outcome of AT/AF ablation in the adult CHD population.

Catheter ablation of atrial arrhythmias by using a multipolar grid-patterned high density mapping catheter in patients with congenital heart disease: a single-center experience

Abstract Objective Catheter ablation of arrhythmias in patients with congenital heart disease (CHD) remains challenging and time-consuming. A novel diagnostic catheter with a multipolar grid-patterned electrode configuration for high density mapping may reduce mapping time and enhance ablation success. Here we describe our experience of catheter ablation by using a multipolar grid-patterned mapping catheter in patients with CHD suffered from atrial tachycardia. Methods All patients with CHD underwent catheter ablation for atrial tachycardia by using multipolar grid-patterned high density mapping catheter between 04/2018 and 12/2021 were enrolled. Primary success was defined as non-inducibility of atrial tachycardia. Only the first catheter ablation was included in the study. Results A total of 37 consecutive patients (median age 34.2±33.0 years (range 7–65), female n=20) underwent 37 ablation procedures with initial high density mapping. The underlying heart defects were s/p ASD-closure (n=2), ASD-closure and corrected partial anomalous pulmonary venous return (n=2), corrected unroofed coronary sinus (n=1), pulmonary valve commissurotomy (n=2), repaired Tetralogy of Fallot (n=2), tricuspid and pulmonary valve replacement in PA/IVS (n=1), mitral valve replacement (n=1), Hypoplastic right heart syndrome (n=1), atrial switch procedure for dTGA (n=7), TA with Glenn shunt (n=1), Ross operation (n=1), Fontan palliation (tricuspid atresia n=6, DILV n=5, HLHS n=1, DORV n=1, dTGA n=1, criss-cross heart n=1, single ventricle n=1). A history of previous ablation was positive in 8 patients. During mapping of the cardiac chambers, the mean value of total collected points and used points were 32657.8±46171 and 3851.6±3295.5 respectively. Mean mapping and fluoroscopy time were 62.1±40.7 minute (range 3–178) and 11.4±8.5 minutes (range 0–32.2), respectively. There were 69 atrial tachycardia substrates in the 37 patients (median 2, range 1–4 per patient). All tachycardia substrates were completely ablated in 33/37 (89.2%) patients and partially in 4/37 (11.8%) patients. Acute success was achieved with successful ablation of 65 of 69 (94.2%) atrial substrates. During a median follow-up time of 20 months (range 5–49), recurrence rate was 5/65 (7.7%) atrial substrates in 5/37 (13.5%) patients. Comparison of 16 patients with Fontan palliation to the 23 patients without Fontan operation showed higher partially success rate in the patients with Fontan palliation (4/16 vs. 0/21, p=0.028). Conclusion In this series, high density mapping allowed elucidation of the tachycardia mechanism in all patients with a high primary ablation success, a limited radiation exposure and a low rate of arrhythmia recurrence. Funding Acknowledgement Type of funding sources: None.

Catheter ablation of atrial tachycardia originated from the left atrial epicardium.

A patient was referred with frequent atrial tachycardia (AT) attacks. Activation mapping showed that the left atrium (LA) roof was earlier activated with a broad region, and right atrial activation was delayed. The far-field A wave corresponding to the pulmonary artery area was advanced with failed ablation. Therefore, the AT could be left atrial epicardial origin, which was further confirmed by the successful ablation at earliest activated site at the epicardium.

Early recurrences after catheter ablation for atrial tachycardia: do we need a blanking period?

Abstract Funding Acknowledgements Type of funding sources: None. Background A blanking period after catheter ablation for atrial fibrillation is widely accepted. The clinical implications of early recurrences (ER) after ablation for atrial tachycardia (AT) in patients with a history of atrial fibrillation have not been analysed so far. Purpose To characterise ER and their relationship with late recurrences (LR) after AT ablation. Methods Acute and long-term outcome was studied in a total of 250 patients undergoing catheter ablation for consecutive AT. ER were defined as any documented atrial arrhythmia &amp;gt;30 s within 3 months after ablation. Results In our study population (66.5±0.7 years, 57.6% male), ER were detected in 80 patients (32.0%), with 74.0% of episodes occurring during the first month post-ablation. Patients with ER had a longer history of any atrial arrhythmia (9.1±0.9 years vs. 6.5±0.4 years; P=0.0283), a larger left atrial diameter (65.7±3.1 mm vs. 49.4±1.4 mm; P=0.0163) and a lower left ventricular ejection fraction (50.8±1.1% vs. 56.6±0.6%; P&amp;lt;0.0001) than those without ER. In patients with ER, AT were more often found to be mitral isthmus-dependent (16.5% vs. 6.2%; P=0.0048) or located at the crista terminalis (3.7% vs. 0.4%; P=0.0343). ER were associated with a 6.0-fold (95% CI 3.27-10.81; P&amp;lt;0.0001) and a 4.3-fold (95% CI 1.72-10.72; P=0.0023) increase in the risk of developing LR after a single or multiple ablation procedures, respectively (Figure). After a mean follow-up of 570±23 days, LR were detected in 78.0% vs. 76.9% vs. 50.0% of patients experiencing the first ER during the first, second or third month (P=0.2266). Among these groups, the first LR occurred after 188.7±20.2 days vs. 259.6±59.1 days vs. 400.8±55.5 days (P=0.0459). Conclusions ER after AT ablation are a predictor of LR and clinical as well as procedural risk factors are associated with the occurrence of ER. The prevalence of LR does not differ among patients with early vs. late ER. These findings underline the prognostic importance of ER and challenge the concept of a blanking period after catheter ablation for AT in patients with a history of atrial fibrillation.

Ablation index predicts outcomes of catheter ablation of focal atrial tachycardia: results of a multicenter study

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation index (AI) is a radiofrequency energy lesion quality marker integrating power, contact force, and time, which was recently shown to be linked to successful catheter ablation (CA) of atrial fibrillation, atrial flutter, and premature ventricular complexes. The possible role of AI as a predictor of outcomes after CA of focal atrial tachycardia (AT) has not been explored so far. Purpose To evaluate the role of AI as a predictor of arrhythmia-free survival after CA of focal AT. Methods We retrospectively enrolled forty-five consecutive patients undergoing CA for focal AT in four referral Italian electrophysiology laboratories. Clinical and procedural information were collected. For each patient, maximum and mean (by averaging maximum AI values for each radiofrequency ablation lesion) values of AI were measured. Focal AT-free survival was the primary outcome, and was assessed with repeated Holter monitors or cardiac implantable electronic devices, when available. The Shapiro-Wilk’s test was used to check continuous variables for normality; non-normal variables were expressed as median (1st-3rd quartile), whereas categorical variables were reported as counts and percentages. The primary outcome was assessed in a time-to-event fashion, with the Kaplan-Meier method, and the role of AI as a predictor of focal AT recurrence was tested with univariable Cox proportional hazard regression. Furthermore, differences in AI values between patients experiencing a primary outcome event and patients not experiencing a primary outcome event were analyzed with the Student t test. Discrimination ability of AI was measured with area under the receiver operating characteristic curve, and the optimal AI cutoff value was identified with Youden’s index. An alpha level &amp;lt;0.05 was considered statistically significant, and the software RStudio (RStudio Inc., Boston, MA) was used for statistical analysis. Results CA was acutely effective in every patient; however, 20% (n=9) of the study population had a focal AT recurrence over a median follow-up of 288 (160-560) days. Both maximum and mean AI values were significantly higher among patients without AT recurrences (maximum AI=568±91, mean AI=426±105) than in patients with AT relapses (maximum AI=447±142, mean AI=352±76, p=0.036 and p=0.028, respectively). All other procedural parameters were similar between the two groups. In a time-to-event analysis, only maximum AI was significantly associated with survival free from AT recurrence (p=0.001, Figure), whereas mean AI was not (p=0.08). By receiver operating characteristic (ROC) curve analysis, the optimal maximum AI cutoff for predicting effective CA according to Youden’s index was 461 (sensitivity, 0.89; specificity, 0.56). Conclusion We observed a strong association between maximum AI and outcomes, suggesting that maximum AI may be regarded as a quantitative marker of successful CA of focal AT.

P1 ATRIAL TACHYCARDIA IN PATIENT WITH TRANSFUSION–DEPENDENT BETA THALASSEMIA AND SEVERE HEMOCHROMATOSIS: A CASE REPORT

Abstract Background Beta thalassemia is the most common inherited disease and it’s characterized by the reduced synthesis of the beta–globin chains of the hemoglobin. Patients usually need long life transfusions since the disease leads to chronic hemolytic anemia. Iron chelation therapy is essential to prevent the chronic iron overload, which is responsible for heart failure, supraventricular and ventricular arrhythmias up to sudden cardiac death. Case Report A 31 year old female patient suffering from transfusion–dependent beta thalassemia has rarely taken iron chelation therapy during the years. Because of that, she developed a severe iron overload and heart failure. Furthermore, she started suffering from several episodes of supraventricular tachycardia and she was referred to our cardiological institution for medical help. She was initially treated with a pharmacological rhythm control strategy, which was ineffective. Then, even if the cardiac iron overload wasn’t completely resolved, we decided to perform an electrophysiological study and catheter ablation of atrial tachycardia. After the ablation, the patient had no more relapses during the follow up and she started to be more adherent with the iron chelation therapy. Discussion Cardiovascular complications are among the main causes of morbidity and mortality in patients suffering from beta thalassemia. Despite the wide use of iron–chelation therapy, today it’s still possible to find patients with severe iron overload. Furthermore, thalassemic patients have a high arrhythmic burden, especially for supraventricular arrhythmias. The best rhythm control treatment is represented by iron chelation therapy but there are still many doubts and open questions about the optimal pharmacological and interventional strategy. This clinical case shows how the interventional approach with catheter ablation can be an useful tool for rhythm control during the acute phase, even when the cardiac iron overload is still present.

Repeat radiofrequency catheter ablation of atrial tachycardias in patients with congenital heart disease.

Atrial tachycardias (AT) in patients with congenital heart disease (CHD) are significantly contributing to morbidity and mortality. Aim of this study was to evaluate the long-term course of CHD patients requiring repeat ablation procedures (RAP) of AT. All 144 patients with CHD who had undergone ablation of AT at our center between January 2003 and October 2018 were enrolled. Patients were classified according to the complexity of CHD: complex CHD (cCHD), moderate CHD (mCHD), and simple CHD (sCHD). A total of 101 RAP were performed in 64 patients. One RAP was performed in n = 40, two in n = 13, three in n = 10, and five in n = 1. Acute success rate was 82% (83/101) and was not associated with the complexity of CHD (p = 1.0). Number of procedures was lower in patients with sCHD than in patients with mCHD and cCHD (sCHD 1.3 ± 0.6, mCHD 1.8 ± 1.0, and cCHD 1.8 ± 1.1, p = .04). RAP were most frequent in patients after Fontan palliation or Atrial switch procedure (2.0 ± 1.1 [n = 41] vs. 1.6 ± 0.9 all others, p = .016) and in patients with multiple unstable AT's (2.5 ± 1.1 [n = 11] vs. 1.7 ± 1.0, p = .008). Major complications occurred in 4/101 procedures. Complete follow-up was available in 125 patients. Since last RAP 73% of the patients were in sinus/atrial rhythm and 34/125 patients (27%) with AT recurrence did not require re-ablation with mean follow-up of 52 ± 40 months. Recurrences after ablation of AT in CHD patients were frequent. After RAP promising long-term results could be achieved. Data encourage repetitive ablation procedures in this patient population.

Ablation Index Predicts Successful Ablation of Focal Atrial Tachycardia: Results of a Multicenter Study.

A radiofrequency energy lesion transmurality marker incorporating power, contact force, and time (Ablation Index, AI) was shown to be associated with outcomes of catheter ablation (CA) of multiple arrhythmias, but was never systematically assessed in the CA of focal atrial tachycardias (AT). We aimed to evaluate the role of AI as a predictor of outcomes in focal AT CA, and therefore, retrospectively included 45 consecutive patients undergoing CA for focal AT in four referral electrophysiology laboratories. Clinical and procedural information were collected. For each patient, maximum and mean (by averaging maximum AI values for each radiofrequency ablation lesion) AI were measured. The primary outcome was focal AT-free survival, and was systematically assessed with periodical Holter monitors or cardiac implantable electronic devices. CA was acutely effective in each case; however, 20% (n = 9) of the study population experienced a focal AT recurrence over a median follow-up of 288 days. Both maximum and mean AI values were significantly higher among patients without AT recurrences (maximum AI = 568 ± 91, mean AI = 426 ± 105) than in patients with AT relapses (maximum AI = 447 ± 142, mean AI = 352 ± 76, p = 0.036, and p = 0.028, respectively). The optimal cutoffs associated with freedom from recurrences were 461 for maximum AI (sensitivity, 0.89; specificity, 0.56) and 301 for mean AI (sensitivity, 0.97; specificity, 0.44). In a time-to-event analysis, maximum AI was significantly associated with survival free from AT recurrence (p = 0.001), whereas mean AI was not (p = 0.08). In summary, maximum AI is the best procedural parameter associated with the outcomes of CA for focal AT, and may help standardize the procedural approach.

Prompt recognition and successful aspiration of a left atrial thrombus under intracardiac echocardiography guidance during radiofrequency catheter ablation for atrial tachycardia.

Prompt recognition and successful aspiration of a left atrial thrombus under intracardiac echocardiography guidance during radiofrequency catheter ablation for atrial tachycardia.

Prevalence and ablation of different anatomic locations of atrial tachicardias in the electrophysiology lab of a single large center

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Focal atrial tachycardias (ATs) can arise from several different anatomic regions both in the right atrium (RA) and left atrium (LA). The prevalence of focal atrial tachycardia is not well known. A European study of young males applying for pilot licenses demonstrated that 0.34% had asymptomatic atrial tachycardia and 0.46% had symptomatic atrial tachycardia1. It is well-recognized that these foci do not occur randomly throughout the atria but tend to cluster at characteristic anatomic locations. However, the distribution of these sites in the total amount of ATs is not well recognized. Purpose The objective of this study was to determine the prevalence of different anatomic locations of ATs in the electrophysiology lab of a single large center (300 ablations per year) and to verify the site of ablation. Methods We collected 150 consecutive patients submitted to catheter ablation of ATs between January 2010 to December 2020. Anatomic localization of the atrial focus was performed during tachicardia by analysis of endocardial activation sequence. Results The distribution of the different anatomic locations is rappresented in the figure. In 134 patients (89%) ATs were localized in the RA. In the RA, these foci mainly occured along the crista terminalis (32%), the perinodal region (22,6%), the anterior right sided septum, near the foramen ovale (9,3%), the posterior right-sided septum (8%), the ostium of the coronary sinus (5,3%), the tricuspid annulus (5,3%), the superior vena cava (4,6%), the infero-lateral wall (2,5%), the right atrial appendage (0,6%) and the cavotricuspid histhmus (0,6%). In the LA (11%), foci occur predominantly at the pulmonary vein ostia (5,2%) and less commonly at the mitral annulus (2,5%), the left sided septum (0,6%), the appendage ridge (0,6%), the roof (0,6%) and the anterior wall (0,6%). For each location of AT, the ablation was performed at the earliest activation site, but about the perinodal ATs, the ablation was performed at the non coronary sinus of Valsalva of the aortic root, regardless the earliest activation site, for avoiding to create damages to the atrio-ventricular (AV) conduction system. Conclusions ATs mainly arise from the RA. Crista terminalis is the most common site but the perinodal region is the second more frequent site. The ablation of ATs from the perinodal region is challenging for the risk of damages to the AV conduction system. The relatively low prevalence of ATs arising from the pulmonary veins could be explained for the likely degeneration of these ATs in atrial fibrillation. Abstract Figure.

Repeat Radiofrequency Catheter Ablation of Atrial Tachycardias in Patients with Congenital Heart Disease

Objectives. Aim of this study was to evaluate the long-term course of patients with congenital heart disease (CHD) requiring repeat ablation procedures (RAP) of atrial tachycardias (AT). Background. Reports on RAP of AT in patients with CHD are sparse.Patients and Methods. All 144 patients with CHD who had undergone ablation of AT at our center between January 2003 and October 2018 were enrolled. Patients were classified according to complexity of CHD: complex CHD (cCHD), moderate CHD (mCHD) and simple CHD (sCHD). Results. A total of 101 RAP were performed in 64 patients. One RAP was performed in n=40, two in n=13, three in n=10 and 5 in n=1. Acute success rate was 82% (83/101) and was not associated with complexity of CHD (p=1.0). Mean number of procedures was lower in patients with sCHD than in patients with mCHD and cCHD (sCHD 1.3{plus minus}0.6, mCHD 1.8{plus minus}1.0 and cCHD 1.8{plus minus}1.1, p=0.04). RAP were most frequent in patients after Fontan palliation or atrial switch procedure (2.0{plus minus}1.1 (n=41) vs. 1.6{plus minus}0.9 all others, p=0.016) and in patients with multiple unstable AT´s (2.5{plus minus}1.1 (n=11) vs. 1.7{plus minus}1.0, p=0.008). Major complications occurred in 4/101 procedures. Complete follow-up was available in 125 patients. Since last RAP 73% of the patients were in sinus/atrial rhythm and 34/125 patients (27%) with AT recurrence did not require re-ablation with mean follow-up of 52{plus minus}40 months. Conclusions. Recurrences after ablation of AT in CHD patients were frequent. After RAP promising long-term results could be achieved. Data encourage repetitive ablation procedures in this patient population.

Unique feature of novel activation mapping to identify the successful ablation site of atrial tachycardia

A 49-year-old man was referred to our hospital for catheter ablation of atrial tachycardia (AT; cycle length 360 ms). He previously underwent pulmonary vein isolation and cavotricuspid isthmus ablation for paroxysmal atrial fibrillation (AF). Conventional activation mapping with the high-density Rhythmia mapping system (Boston Scientific, Marlborough, MA) revealed the following features: (1) activation breaking out at the inferior wall below the left inferior pulmonary vein in a centrifugal pattern (Online Supplemental Figure 1) and (2) AF was observed inside the left pulmonary vein (LPV) (Figure 1A, a).

Outcome after tailored catheter ablation of atrial tachycardia using ultra-high-density mapping.

Tailored catheter ablation of atrial tachycardias (ATs) is increasingly recommended as a potentially easy treatment strategy in the era of high-density mapping (HDM). As follow-up data are sparse, we here report outcomes after HDM-guided ablation of ATs in patients with prior catheter ablation or cardiac surgery. In 250 consecutive patients (age 66.5 ± 0.7 years, 58% male) with ATs (98% prior catheter ablation, 13% prior cardiac surgery) an HDM-guided catheter ablation was performed with the support of a 64-electrode mini-basket catheter. A total of 354 ATs (1.4 ± 0.1 ATs per patient; mean cycle length 304 ± 4.3 ms; 64% macroreentry, 27% localized reentry, and 9% focal) with acute termination of 95% were targeted in the index procedure. A similar AT as in the index procedure recurred in five patients (2%) after a median follow-up time of 535 days (interquartile range (IQR) 25th-75th percentile: 217-841). Tailored ablation of reentry ATs with freedom from any arrhythmia was obtained in 53% after a single procedure and in 73% after 1.4 ± 0.4 ablation procedures (range: 1-4). A total of 228 patients (91%) were free from any arrhythmia recurrence after 210 days (IQR: 152-494) when including optimal usual care. Tailored catheter ablation of ATs guided by HDM has a high acute success rate. The recurrence rate of the index AT is low. In patients with extensive atrial scaring further ablation procedures need to be considered to achieve freedom from any arrhythmia.