Atrial Tachycardia In Patients Research Articles

Posterior left atrial isolation is associated with a lower incidence of atrial tachycardia in patients with persistent atrial fibrillation.

Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF). The population consisted of 101 consecutive patients (age = 64.3 ± 8.7years, 70 males (69%), LA = 4.6 ± 0.8cm, ejection fraction = 48.5 ± 16%) undergoing their initial procedure for persistent AF. After pulmonary vein isolation, patients either underwent posterior LA isolation (n = 50; study group) or linear ablation at the LA roof with verification of conduction block (n = 51; control group). A repeat procedure was performed in 17 (34%) and 28 (55%) patients in the study and control groups, respectively (p = 0.02). Patients in the study group were less likely to develop AT (9/50 [18%] vs. 18/51 [35%]; p = 0.02), roof-dependent (1/50 [2%] vs. 8/51 [16%]; p = 0.008), and multi-loop AT (6/50 [12%] vs. 14/51 [27%]; p = 0.03) as compared to controls. Among various factors, only posterior LA isolation was associated with a lower likelihood of AT recurrence and roof tachycardia at redo procedure (OR, 0.37; 95% CI, 0.1 to 1.00, p = 0.05, and OR, 0.1, 95% CI, 0.01 to 0.96; p < 0.05, respectively). In patients with persistent AF, posterior LA isolation is associated with a lower risk of a redo procedure, roof-dependent macro-reentry, and post-ablation AT in general as compared to controls who only received roof ablation. Posterior LA isolation also obviates the need for pacing maneuvers, and may be a more definitive endpoint than linear ablation at the LA roof.

High density mapping of atrial tachycardia in patients post cardiac surgery.

Mapping and ablation of atrial tachycardia (AT) in patients who have had prior cardiac surgery can be a challenge for clinical electrophysiologists. High density mapping (HDM) technology has been widely used in these patients because it provides a better characterization of the substrate and the mechanisms with an unprecedented high resolution. In this review, we summarize how the latest HDM technologies can reveal the mechanism of AT in different types of patients post-cardiac surgery and guide a specifically tailored ablation strategy.

Catheter ablation of atrial fibrillation and atrial tachycardia in patients with pulmonary hypertension: a randomised study

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The study was supported by the Ministry of Health of the Czech Republic. Background Atrial fibrillation (AF) and other atrial tachycardias (ATs), including typical atrial flutter (AFL), are common in patients with pulmonary hypertension. Frequently, several supraventricular arrhythmias are successively observed in individual patients. Purpose We investigated the hypothesis of whether more extensive radiofrequency catheter ablation of the bi-atrial arrhythmogenic substrate instead of clinical arrhythmia ablation alone results in superior clinical outcomes in patients with PH and AF / AT. Methods Patients with combined post- and pre-capillary or isolated pre-capillary PH and AF / AT indicated to catheter ablation were enrolled in 3 centers and randomized 1:1 into two parallel treatments arms: (A) Clinical arrhythmia ablation and (B) Clinical arrhythmia plus substrate-based ablation. The primary endpoint was arrhythmia recurrence &amp;gt;30 s without antiarrhythmic drugs after the 3-month blanking period. Results A total of 77 patients (mean age 67 ± 10 years; 41 males) were enrolled. The presumable clinical arrhythmia was AF in 38 and AT in 36 patients, including typical AFL in 23 patients. During the median follow-up period of 13 (IQR: 12; 19) months, the primary endpoint occurred in 15 patients (42 %) vs. 17 patients (45 %) in the group B vs. A (hazard ratio: 0.97, 95% confidence interval: 0.49-2.0). There was no excess of procedural complications and clinical follow-up events including an all-cause death in group B. Conclusion Extensive ablation, compared with a limited approach, was not beneficial in terms of arrhythmia recurrence in patients with AF / AT and pulmonary hypertension.

Omitting transesophageal echocardiography before catheter ablation of atrial fibrillation or left sided atrial tachycardia in patients on oral anticoagulation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation (CA) is accepted as a safe and effective therapy for atrial Fibrillation AF and left sided atrial tachycardias (AT) and is a well-established standard of care. However, the procedure can lead to life-threatening complications, including thromboembolic cerebrovascular events (CVE). Transesophageal echocardiography (TOE) is the gold standard for screening for left atrial appendage thrombus (LAAT) and is performed in many cases prior to CA of AF. However, the guidelines are limited on the precise role of LA imaging for thrombus detection prior to CA. Purpose The aim of our retrospective analysis was to evaluate the safety of individualized TOE approach for patient undergoing CA of AF or left sided AT in the two participating centers. Methods Patients, undergone AF or left sided AT ablation between August 2018 and October 2022 at two centers were enrolled. Patients were scheduled to TOE when one of the following criteria was met: 1) prior history of either thromboembolic stroke or 2) LAAT, 3) inappropriate anticoagulation (OAK) regimen in 4 weeks prior to CA. Otherwise, no TOE prior to CA was performed. (Figure 1). TOE and CA outcomes were retrospectively analyzed. CVE incidence from the procedure onset to 24 hours post-procedure was evaluated. Results A total of 1156 Patients were analyzed. The median age of study population was 70 (IQR: 62-76) years. 675 patients (58.4%) were male, 555(48.1%) had a persistent AF/AT and 358 (31%) had already left atrial CA in prior history. The CHA2DS2-VASc score was ≥ 2 in 939 (81.2%) patients. 505 patients (43.7%) were on apixaban, 359(31.0%) on rivaroxaban, 22 (1,9%) on dabigatran, 103 (8.9%) on edoxaban, 94(8.13%) on VKA, 73(6.3%) had no OAK prior to ablation (6 patients due to previous LAA occluder implantation, in 1 patient due to LAA resection). The median left ventricular ejection fraction was 59% (IQR: 50-60%), median left atrial volume index was 43.6 (IQR: 28.8-55) ml/m2.TOE was performed in 261 (22.6%) of patients, in 93 due to stroke history, in 24 due to LAAT history, in 161 due to inappropriate OAK. No LAA Thrombi were detected. Total 4 out of 1156 (0.35%) experienced CVE (Table 1). In 2 of these cases TOE was performed prior to CA, and LAA thrombi were ruled out. In another 2 patients in heart computer tomography immediately after stroke LAAT were excluded. Even not statistically significant, the higher rate of the CVE among the patients with TOE performed (2 out of 261 patients, 0.76%) emphasizes the higher baseline risk of thromboembolic events in this category of patients as opposed to the patients with low stroke risk where TOE was omitted (2 out of 895 patients, 0.22%, p=0.22). Conclusions Individualized selective approach to TOE prior to CA of AF or left sided AT showed to be safe. The stroke incidence (0.35%) in this approach was not higher, than in large cohort studies. In patients with uninterrupted OAK and low stroke risk TOE prior to CA could be omitted.

Catheter ablation of atrial fibrillation and atrial tachycardia in patients with pulmonary hypertension: a randomized study

Atrial fibrillation (AF), typical atrial flutter (AFL), and other atrial tachycardias (ATs) are common in patients with pulmonary hypertension. Frequently, several supraventricular arrhythmias are successively observed in individual patients. We investigated the hypothesis of whether more extensive radiofrequency catheter ablation of the bi-atrial arrhythmogenic substrate instead of clinical arrhythmia ablation alone results in superior clinical outcomes in patients with pulmonary arterial hypertension (PH) and supraventricular arrhythmias. Patients with combined post- and pre-capillary or isolated pre-capillary PH and supraventricular arrhythmia indicated to catheter ablation were enrolled in three centres and randomized 1:1 into two parallel treatment arms. Patients underwent either clinical arrhythmia ablation only (Limited ablation group) or clinical arrhythmia plus substrate-based ablation (Extended ablation group). The primary endpoint was arrhythmia recurrence >30 s without antiarrhythmic drugs after the 3-month blanking period. A total of 77 patients (mean age 67 ± 10 years; 41 males) were enrolled. The presumable clinical arrhythmia was AF in 38 and AT in 36 patients, including typical AFL in 23 patients. During the median follow-up period of 13 (interquartile range: 12; 19) months, the primary endpoint occurred in 15 patients (42%) vs. 17 patients (45%) in the Extended vs. Limited ablation group (hazard ratio: 0.97, 95% confidence interval: 0.49-2.0). There was no excess of procedural complications and clinical follow-up events including an all-cause death in the Extended ablation group. Extensive ablation, compared with a limited approach, was not beneficial in terms of arrhythmia recurrence in patients with AF/AT and PH. ClinicalTrials.gov; NCT04053361.

Coherent mapping of atrial tachycardias in patients with congenital heart disease.

Coherent mapping (CM) uses a new algorithm to identify critical conduction isthmuses of atrial tachycardias (ATs). We analysed our experience of ablation of AT in patients with congenital heart disease (CHD) with this new technology. All patients with CHD who had CM of AT using the high-density mapping PENTARAY™ catheter and three-dimensional electroanatomic mapping system Carto3 between June 2019 and June 2021 were included retrospectively (n = 27). As a control group, 27 patients with CHD and mapping of AT without CM between March 2016 and June 2019 were included. In total, 54 ablation procedures were performed in 42 patients [median age 35 (interquartile range, IQR 30-48) years] and 64 ATs were induced and mapped (thereof 50 AT intraatrial re-entrant tachycardia and 14 AT ectopic AT). The median procedure duration was 180 (120-214) min and median fluoroscopy time was 10 (5.2-14) min. Acute success was 100% (27/27) in the Coherence group and 74% (20/27) in the non-Coherence group (P = 0.01). During follow-up [median 26 (12-45) months], AT recurred in 28/54 patients, thereof 15 patients needed a re-ablation procedure. Log-rank test showed no difference in recurrence rate between the two groups (P = 0.29). Three minor complications occurred (5.5%). Mapping of AT in patients with CHD using the PENTARAY™ mapping catheter and the CM algorithm led to excellent acute success. All ATs were possible to map and no complications related to the PENTARAY™ mapping catheter were observed. Thus, the use of the CM algorithm represents a promising tool in patients with CHD and complex AT.

Reverse structural left atrial remodeling and atrial tachycardia in patients with repeat ablation for atrial fibrillation.

Catheter ablation has been evolved to a cornerstone in the therapy of atrial fibrillation (AF); however, atrial tachycardias (AT) after AF ablation are still an important issue. Besides the electrical recurrence of atrial tachyarrhythmia after ablation, left atrial (LA) remodeling has received attention as a consequence of AF. The aim of this study is to evaluate predictors for AT recurrence and LA remodeling in patients with repeat AF ablation procedures. One hundred thirteen patients who underwent repeat AF ablation with 3D electro-anatomical mapping system were evaluated. Mean age was 63.1 ± 9.3 years, and 2.3 ± 0.5 ablation procedures were performed during a time period of 22 [IQR 7;48] months. Reverse structural LA remodeling (LA volume decreased more than 15%) was observed in 25 (22.1%) patients. LA volume index (LAVI) during first procedure was the only predictor for positive reverse structural LA remodeling (hazard ratio (HR): 1.03, 95% CI: 1.00-1.07, p = .036) in multivariate analysis. Fifty-nine (52.2%) patients experienced only AF and 54 (47.8%) patients AT after first procedure. Female gender (HR: 5.21, 95% CI: 1.66-18.08, p = .006), LAVI (HR: 1.06, 95% CI: 1.02-1.11, p = .008) and LA scar percentage (HR: 1.08, 95% CI: 1.02-1.17, p = .019) were independent significant predictors for AT recurrence in multivariate analysis. Reverse structural LA remodeling occurred in a quarter of patients with repeat ablation procedures for AF. Only larger LAVI during first procedure predicted reverse structural LA remodeling. Half of the patients experienced AT between first and last ablation procedure. Female gender, larger LAVI and larger scar area were significant predictors for AT after catheter ablation for AF.

Abstract 14874: Electrical Isolation of the Posterior Left Atrium is Associated With a Lower Incidence of Atrial Tachycardia in Patients With Persistent Atrial Fibrillation

Introduction: Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF). Hypothesis: We hypothesized that patients with persistent AF undergoing electrical isolation of the posterior wall of the LA would be less likely to experience AT, and specifically, roof-dependent tachycardia as compared to historical controls who only received linear ablation at the LA roof. Methods: The population consisted of 101 consecutive patients (age= 64.3±8.7 years, 70 males (69%), LA=4.6±0.8 cm, ejection fraction=48.5±16%) undergoing their initial procedure for persistent AF. After pulmonary vein isolation, patients either underwent posterior LA isolation (n=50; study group) or linear ablation at the LA roof with verification of conduction block by established pacing maneuvers (n=51; control group) Results: During the initial procedure for AF, electrical isolation of the posterior LA or linear block at the LA roof were achieved in all patients in the study or control groups, respectively. During follow-up, patients in the study group were less likely to develop AT (9/50 [18%] vs. 18/51 [35%]; p=0.02), roof-dependent (1/50 [2%] vs. 8/51 [16%]; p=0.008), and multi-loop AT (6/50 [12%] vs. 14/51 [27%]; p=0.03) as compared to controls. A repeat procedure was performed in 18 (34%) and 28 (55%) patients in the study and control groups, respectively (p=0.03). After a mean follow-up of 25.3 ± 13, and 50.3 ± 27.3 months, 45 of the 50 study (90%), and 44 of the 51 control patients (86%) remained in sinus rhythm (p=0.72), with 12 and 13 patients taking antiarrhythmic medications, respectively (p=0.43) Conclusions: In patients with persistent AF, posterior LA isolation is associated with a lower risk of a redo procedure, roof-dependent macro-reentry, and post-ablation AT in general as compared to controls who only received linear ablation of the left atrial roof. Posterior LA isolation also obviates pacing maneuvers, the results of which might be equivocal, and may be a more definitive endpoint of linear ablation at the LA roof

Electroanatomic mapping and radiofrequency catheter ablation of atrial fibrillation or atrial tachycardia in patients with pulmonary hypertension. Ancillary analysis

Abstract Background Atrial fibrillation (AF) and related atrial tachycardias (ATs) are common arrhythmias in patients with pulmonary hypertension (PH). They are currently assessed in a multicentre randomized trial investigating extensive radiofrequency catheter ablation of the arrhythmogenic substrate on top of selective ablation of clinical arrhythmia alone. Purpose Irrespective of the randomization scheme, we compared clinical and procedural characteristics in patients with AF versus those with right-sided ATs. Methods Out of 74 patients with combined post- and pre-capillary or isolated pre-capillary PH, two study subgroups were composed: AF group included 40 patients and AT group included 31 patients: 24 with typical atrial flutter (AFL) and 7 with other right-sided ATs (2 upper loop reentry ATs, 2 focal ATs from coronary sinus ostium, 1 focal AT from terminal crest, and 2 polymorphic ATs from high right atrium). Three patients with inducible AV nodal reentrant tachycardia were excluded from this analysis. Biatrial electroanatomic mapping was performed in all patients. The data are presented as medians (interquartile range) and compared by the Mann-Whitney U test. Results The clinical and procedural characteristics of AF and AT groups are shown in Table. Cycle length (CL) of both induced and spontaneous AFL was 302 (267; 324) ms. Non-CTI-dependent ATs had CL 425 (350; 480) ms. In patients with AF, the dominant CL was 183 (152; 221) and 191 (154; 210) ms in right and left atrial appendage, respectively. In the whole cohort, pulmonary vein isolation was done in 49 (66%), left atrial substrate ablated in 23 (31%), cavotricuspid isthmus block achieved in 46 (62%), superior vena cava isolation completed in 28 (39%), intercaval line ablated in 26 (36%), and right atrial substrate or focal activity ablated in 8 (11%) cases. The procedure was technically successful in 72 (97%) patients. Conclusion Patients with right-sided ATs had expectedly more dilated right atrium. This was not, however, associated with a higher prevalence of right atrial low-voltage areas. Left atrial electroanatomic remodelling in AF patients was concordant with that frequently observed in non-PH patients with AF. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic.

Characteristics and Ablation Outcomes of Atrial Tachycardia in Patients with Prior Cardiac Surgery vs. Spontaneous Scars: Where Are the Differences?

(1) Background: Atrial scars play an important role in atrial tachycardia (AT). They can not only be found in patients with prior cardiac surgery (PCS) but also in patients without PCS or significant structural heart disease, in which case the scar is called a spontaneous scar (SS). This study aims to compare the characteristics, mechanisms and ablation outcomes of AT in patients with PCS and SS. (2) Methods: We retrospectively reviewed electrophysiological and ablative characteristics of ATs in 46 patients with PCS and 18 patients with SS. (3) Results: There were averages of 1.52 and 2.33 ATs per patient in the PCS group and SS group, respectively (p < 0.01). Cavo-tricuspid isthmus dependent atrial flutter (CTI-AFL) was presented in most patients in both groups (93.50% vs. 77.80%, p = 0.17), whereas the SS group had a higher occurrence of scar-mediated reentrant AT (SMAT) and focal AT (FAT) compared with the PCS group (88.90% vs. 39.10%, p < 0.01; 22.2% vs. 2.2%, p < 0.05). There were no significant differences in acute success rate between the two groups, whereas patients with SS had lower long-term success rate (87.0% vs. 61.1%, p < 0.05) and higher occurrence of sinus node dysfunction (SND) (4.3% vs. 22.2%, p < 0.05). (4) Conclusions: CTI-AFL is common in both patients with PCS and SS, and routine CTI ablation is recommended. Compared with patients with PCS, patients with SS have more ATs, especially with higher occurrence of SMAT and FAT, and had a lower long-term success rate and higher incidence of SND.

Left Atrial Anterior Wall Scar-Related Atrial Tachycardia in Patients after Catheter Ablation or Cardiac Surgery: Electrophysiological Characteristics and Ablation Strategy.

Background: The mechanisms of atrial tachycardia (AT) related to the left atrial anterior wall (LAAW) are complex and can be challenging to map in patients after catheter ablation for atrial fibrillation (AF) or cardiac surgery. We aimed to investigate the electrophysiological characteristics AT and to devise an ablation strategy. Methods and Results: We identified 31 scar-related LAAW reentrant ATs in 22 patients after catheter ablation for AF or cardiac surgery. Activation maps of the left atrium (LA) or both atria were obtained using a high-density mapping system, and the precise mechanism and critical area for each AT were analyzed. Patients were followed up regularly in a clinic. After analyzing the activation and propagation of each AT, the scar-related LAAW ATs were classified into three types, based on mechanisms related to: (1) LAAW conduction gap(s) in 19 LA macro-reentrant ATs; (2) LAAW epicardial connection(s) in 11 LA or bi-atrial ATs; and (3) LAAW local micro-reentry in 1 LAAW AT. Multiple ATs were identified in seven patients. Effective ablation (termination or circuit change of AT) was obtained in 30 ATs by targeting the critical area identified by the mapping system. During 16.0 ± 7.6 months follow-up, recurrent AT occurred in two patients. Conclusions: Three mechanisms of scar-related AT of LAAW were identified, most of which were related to LAAW conduction gaps. Notably, epicardial AT or bi-atrial AT comprised a nonnegligible proportion. A high-density mapping system could make it possible to determine the accurate mechanism of AT and serve as a guide following ablation.

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.

The Role of Pulmonary Artery Wedge Pressure on the Incidence of Atrial Fibrillation and Atrial Tachycardias in Patients With Isolated Pre-capillary Pulmonary Hypertension.

Atrial fibrillation and atrial tachycardias (AF/AT) have been reported as a common condition in patients with pulmonary hypertension (PH). As yet, limited data exists about the significance of the borderline post-capillary pressure component on the occurrence of AF / AT in patients with isolated pre-capillary PH. We retrospectively studied the prevalence of AF / AT in 333 patients (mean age 61 ± 15 years, 44% males) with pre-capillary idiopathic / familiar pulmonary arterial hypertension, and inoperable chronic thromboembolic pulmonary hypertension. The prevalence of AF / AT was analyzed in different categories of pulmonary artery wedge pressure (PAWP). In the study population overall, the mean PAWP was 10.5 ± 3 mmHg, median of 11 mmHg, range 2-15 mmHg. AF / AT was diagnosed in 79 patients (24%). The proportion of AF / AT among patients with PAWP below the median (?11 mmHg) was lower than in subjects with PAWP between 12 and 15 mmHg, 30 (16%) vs. 46 (35%), p = 0.0001. Compared to the patients with PAWP?11 mmHg, subjects with PAWP between 12 and 15 mmHg were older (65 ± 13 years vs. 58 ± 16), with more prevalent arterial hyperte\nsion [100 (70%) vs. 106 (55%)] and diabetes mellitus [50 (35%) vs. 48 (25%)], showed larger size of the left atrium (42 ± 7 vs. 40 ± 6 mm), and higher values of right atrium pressure (12 ± 5 vs. 8 ± 5 mm Hg), p < 0.05 in all comparisons. The prevalence of AF / AT in the group studied increased with the growing post-capillary component.

Ultra-high-density mapping and ablation strategy for multiple scar-related right atrial tachycardias in patients without previous cardiac surgery.

Catheter ablation of right atrial (RA) tachycardia in patients who have extensive spontaneous RA scarring is challenging due to the complex substrate and the potential for multiple inducible atrial tachycardias (ATs). Eighteen patients with scar-related RA AT and no prior cardiac surgery were enrolled. A total of 52 different ATs (mean 3.2 ± 1.5 ATs per patient) were observed. We endeavored to complete activation maps for 45 ATs. By analyzing activation maps, we classified ATs into six categories. The discrepant location and extension of ESAs were associated with different AT mechanisms. Multiple scar-related RA ATs were observed in patients without previous cardiac surgery. The detailed activation patterns of these ATs could be clearly demonstrated by using an ultra-high-density mapping system.

Reverse Structural Atrial Remodeling and Atrial Tachycardia in Patients with Repeat Ablation for Atrial Fibrillation

Background: Catheter ablation has been evolved to a cornerstone in the therapy of atrial fibrillation (AF), however atrial tachycardias (AT) after AF ablation are still an important issue. Besides the electrical recurrence of atrial tachyarrhythmia after ablation, left atrial (LA) remodeling has received attention as a consequence of AF. Objective: The aim of this study is to evaluate predictors for AT recurrence and LA remodeling in patients with repeat AF ablation procedures. Methods and Results: One hundred thirteen patients who underwent repeat AF ablation with 3D electro-anatomical mapping system were evaluated. Mean age was 63.1{plus minus}9.3 years, and 2.3{plus minus}0.5 ablation procedures were performed during a time period of 22 [IQR 7;48] months. Reverse structural LA remodeling (LA volume decreased more than 15%) was observed in 25 (22.1%) patients. LA volume index (LAVI) during first procedure was the only predictor for positive reverse structural LA remodeling (hazard ratio (HR):1.03, 95%CI:1.00-1.07, p=0.036) in multivariate analysis. Fifty-nine (52,2%) patients experienced only AF and 54 (47.8%) patients AT after first procedure. Female gender (HR:5.21, 95%CI:1.66-18.08, p=0.006), LAVI (HR:1.06, 95%CI:1.02-1.11, p=0.008) and LA scar percentage (HR:1.08, 95%CI:1.02-1.17, p=0.019) were independent significant predictors for AT recurrence in multivariate analysis. Conclusions: Reverse structural LA remodeling occurred in a quarter of patients with repeat ablation procedure for AF. Only larger LAVI during first procedure predicted reverse structural LA remodeling. Half of patients experienced AT between first and last ablation procedure. Female gender, larger LAVI and larger scar area were significant predictors for AT after catheter ablation for AF.

The isthmus characteristics of scar-related macroreentrant atrial tachycardia in patients with and without cardiac surgery.

Identifying the critical isthmus (CI) in scar-related macroreentrant atrial tachycardia (AT) is challenging, especially for patients with cardiac surgery. We aimed to investigate the electrophysiological characteristics of scar-related macroreentrant ATs in patients with and without cardiac surgery. A prospective study of 31 patients (mean age 59.4 ± 9.81 years old) with scar-related macroreentrant ATs were enrolled for investigation of substrate properties. Patients were categorized into the nonsurgery (n = 18) and surgery group (n = 13). The CIs were defined by concealed entrainment, conduction velocity less than 0.3 m/s, and the presence of local fractionated electrograms. Among the 31 patients, a total of 65 reentrant circuits and 76 CIs were identified on the coherent map. The scar in the surgical group is larger than the nonsurgical group (18.81 ± 9.22 vs. 10.23 ± 5.34%, p = .016). The CIs in surgical group have longer CI length (15.27 ± 4.89 vs. 11.20 ± 2.96 mm, p = .004), slower conduction velocity (0.46 ± 0.19 vs. 0.69 ± 0.14 m/s, p < .001), and longer total activation time (45.34 ± 9.04 vs. 38.24 ± 8.41%, p = .016) than those in the nonsurgical group. After ablation, 93.54% of patients remained in sinus rhythm during a follow-up of 182 ± 19 days. The characteristics of the isthmus in macroreentrant AT are diverse, especially for surgical scar-related AT. The identification of CIs can facilitate the successful ablation of scar-related ATs.

Ultrahigh Density Mapping for Multiple Scar-Related Right Atrial Tachycardias in Patients Without Previous Cardiac Surgery

Objective: We sought to investigate the precise electrophysiological mechanisms of multiple scar-related RA ATs using an ultrahigh density mapping system. Methods: Eighteen patients with scar related RA AT and no prior cardiac surgery were enrolled. In each case, we sought to map each AT circuit in detail. Low-voltage zones(LVZs) ,electrically silent areas(ESAs) and lines of double potentials (LDPs) were all visualized on the voltage and activation map. Results: A total of 52 different ATs (mean 3.2{plus minus}1.5 ATs per patient) were observed . We endeavored to complete activation maps for 45 ATs. In all cases, a large area of LVZ was located between the crista terminalis(CT) and the tricuspid annulus(TA). Inside the LVZ, several discrete ESAs or LDPs separated by a low-voltage channel were present. By analyzing activation maps, we classified ATs into six categories. The discrepant location and extension of ESAs were associated with different AT mechanisms. Conclusions: Multiple scar related RA ATs were observed in patients without previous cardiac surgery. The detailed activation patterns of these ATs could be clearly demonstrated by using an ultra-high density mapping system.

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.

Low-Voltage Areas as Alternative Targets for the Ablation of Unmappable Atrial Tachycardia in Patients Undergoing Atrial Fibrillation Ablation.

Unmappable regular atrial tachycarrhythmias (ATs) occasionally develop during atrial fibrillation (AF) ablation, and are difficult to treat by conventional ablation. Recently, low-voltage areas (LVAs) have been reported to represent AT substrate. The purpose of this study was to elucidate the efficacy of LVA ablation for unmappable AT. This observational study included 32 consecutive patients who developed unmappable ATs during and after AF ablation. Unmappable AT was defined as AT lasting for >5 s, but that terminated or changed the activation sequence over too short a time to create a sufficient activation map. We used conventional ablation to target undetermined AT circuits estimated from activation timings of electrograms recorded on the placed electrode catheter, the response to entrainment mappings, and/or diastolic potentials during AT. Subsequently, in cases without successful elimination of unmappable ATs by conventional ablation, LVA (≤ 0.5 mV) ablation was performed at the discretion of the operators. Conventional ablation failed to eliminate at least one unmappable AT in 29 patients. Among them, LVA ablation was performed in 16 patients. LVA ablation eliminated all the unmappable ATs in 8 of 16 patients. The LVA size did not differ between patients with and without the acute elimination of unmappable ATs (17±11 vs. 21±12 cm2, p = 0.39), and AT/AF recurrence rates were comparable between the two groups (38% vs. 63%, p = 0.62) during a mean follow-up period of 14±8 months. LVA ablation was efficacious to some extent for the elimination of unmappable ATs refractory to conventional ablation.

Catheter ablation of atrial arrhythmias in patients after thoracoscopic ablation of persistent atrial fibrillation

Aim. To determine the mechanisms of development and approaches to interventional treatment of postoperative atrial tachycardia in patients after thoracoscopic ablation (TA) of atrial fibrillation (AF). Material and methods . The results of thoracoscopic ablation of AF in 46 patients were analyzed, of which 19,5% (n=9) had atrial tachycardia after the procedure. Radiofrequency ablation (RFA) was conducted in these patients after a 3-month blanking period. Regardless of tachycardia type, the threedimensional reconstruction including high-density right and left atrial (LA) voltage mapping was performed in order to visualize the lesions, pulmonary veins and LA posterior wall isolations. After RFA and sinus rhythm restoration, re-mapping was performed to assess conduction block and absence of electrical activity in the lesion zones. Results. Complete pulmonary vein (PV) isolation was verified in 55,5% of patients (n=5). In 44,4% (n=4), there were residual PV fractionated potentials without conduction with LA. In 22,2% of subjects (n=2), we identified typical atrial flutter (AFL), which was terminated by RFA in cavotricuspid isthmus (CTI). There were 77,7% (n=7) of patients who were diagnosed with atypical LA flutter; 66,6% (n=6) of them had conduction reconnection at the thoracoscopic box-lesion line. Perimitral AFL with slow conduction zone which was located on the anterior wall of LA was verified in 11,1% of patients (n=1). The effective RFA was performed in these areas. Two main factors affecting failed ablation were LA volume and body mass index (BMI). In patients with arrhythmias after TA, LA volume was 180,2±35,6 ml vs 158,34±38,5 ml in patients with sinus rhythm. BMI was 30,8±3,1 kg/m2 and 28,9±3,9 kg/m2, respectively. The mean follow-up was 9,8±2,7 months. All patients after catheter ablation maintained a stable sinus rhythm. Conclusion. Atrial tachycardia after TA is caused by the gaps in box-lesion lines. The main predictors of gaps are high values of LA volume and BMI. The high-density mapping increases the effectiveness of RFA. Combination of epicardial and endocardial accesses is the most effective approach to treatment of patients with persistent AF.