Bipolar endo-epicardial RF ablation: Animal feasibility study.

BACKGROUND: Bipolar radiofrequency ablation (B-RFA) is a method used to treat the arrhythmia substrate resistant to unipolar ablation. Few studies have addressed endo-epicardial B-RFA. OBJECTIVE: The aim of the study was to evaluate chronic lesions resulting from endo-epicardial B-RFA and to determine optimal settings for such procedures in an animal model. METHODS: In 7 pigs, up to 5 radiofrequency applications per animal were performed with 2 electrodes placed on both sides of the left ventricular free wall. Current was delivered for 60 seconds by a generator dedicated for B-RFA with power settings of 25, 30, 35, 40, and 50 W. RESULTS: At 12 weeks after ablation, 31 lesions were assessed. Their maximal cross-sectional area ranged from 7.2 to 68 mm2 and correlated with total power delivered (r = 0.53), with temperature increment at the endocardial catheter (r = 0.65), and inversely with temperature decrement at the epicardial catheter (r = 0.54). For power values between 30 and 40 W, the lesion area did not differ significantly (P = .92). Lesion depth ranged from 1.9 to 11 mm and correlated with impedance decrement (r = 0.5). Lesions were transmural in 8 cases. Lesion depth/wall thickness ratio was on average 0.6 ± 0.3, with the smallest value for 25 W (0.5 ± 0.3) and the largest for 50 W (0.8 ± 0.3). Steam pops occurred at a power range of 30-50 W, with an incidence of 1 in 5 applications, with 1 case of fatal tamponade at 40 W. Impedance decrement, endocardial catheter temperature increment, and endocardial electrogram amplitude decrement were greater during applications with steam pops. CONCLUSION: Chronic lesions resulting from endo-epicardial B-RFA appear smaller and less often transmural compared with acute lesions described in the literature. The incidence of steam pops during endo-epicardial B-RFA is relatively high even at low powers.

Cardiac Pulsed Field Ablation Lesion Durability Assessed by Polarization-Sensitive Optical Coherence Reflectometry.

BACKGROUND: Pulsed field ablation uses electrical fields to cause nonthermal cell death over several hours. Polarization-sensitive optical coherence reflectometry is an optical imaging technique that can detect changes in the tissue ultrastructure in real time, which occurs when muscular tissue is damaged. The objective of this study was to evaluate the ability of a polarization-sensitive optical coherence reflectometry system to predict the development of chronic lesions based on acute changes in tissue birefringence during pulsed field ablation. METHODS: Superior vena cava isolation was performed in 30 swine using a biphasic, bipolar pulsed field ablation system delivered with a nonirrigated focal tip catheter. Acute changes in tissue birefringence and voltage abatement were analyzed for each individual lesion. A high-resolution electroanatomical map was performed at baseline and 4 to 12 weeks after ablation to locate electrical gaps in the ablated area. RESULTS: A total of 141 lesions were delivered and included in the analysis. Acute electrical isolation based on the electroanatomical map was achieved in 96% of the animals, but chronic isolation was only seen in 14 animals (46%). The mean voltage abatement of lesions that showed recovery was 82.8%±14.6% versus 84.4%±17.4% for those that showed fibrosis (P=0.7). The mean acute reduction in tissue birefringence in points demonstrating fibrosis was 63.8%±11.3% versus 9.1%±0.1% in the points that resulted in electrical gaps. A threshold of acute reduction of birefringence of ≥20% could predict chronic lesion formation with a sensitivity of 96% and a specificity of 83%. CONCLUSIONS: Acute tissue birefringence changes assessed with polarization-sensitive optical coherence reflectometry during pulsed field ablation can predict chronic lesion formation and guide the ablation procedure although limited by the tissue thickness.

Cryoballoon ablation without use of contrast for the treatment of paroxysmal atrial fibrillation.

BACKGROUND: Cryoballoon ablation (CBA) for atrial fibrillation (AF) is usually preceded by demonstrating pulmonary vein (PV) occlusion using contrast. The aim of the study was to determine efficacy and safety of a simplified protocol for CBA performed without demonstrating PV occlusion and compare achieved results with conventional CBA. METHODS: Paroxysmal AF patients undergoing a first-time CBA were prospectively included. In the non-contrast (NC) group CBA was performed using standardized protocol without demonstrating PV occlusion. In the conventional contrast (CC) group ablations were performed after confirmation of PV occlusion. RESULTS: The NC and CC groups comprised 51 and 22 patients, respectively. PVI according to the group assignment was achieved in 34 (67%) and 21 (95.5%) patients from the NC and CC groups, respectively (p < 0.001). In the NC group, 184 (90%) out of 204 veins were isolated without venography. There were no differences between the NC and CC groups in terms of procedure duration (89.7 ± 22.6 vs. 90.0 ± 20.6 min; p = 0.7) and fluoroscopy time (15.3 ± 6.3 vs. 15 ± 4.5 min; p = 0.8). In the NC group, the use of contrast was significantly lower compared to the CC group (4.9 ± 10.1 vs. 19.4 ± 8.6 mL, p < 0.001). There were no serious adverse events in both groups. A 1-year freedom from AF was achieved in 73.5% and 71.5% of patients from the NC and CC groups, respectively (p = 1). CONCLUSIONS: Cryoballoon ablation without demonstrating vein occlusion with contrast is safe and feasible. Proposed simplified approach enables isolation of the vast majority of pulmonary veins with a significant reduction in the amount of contrast used.

Bipolar Endo-Epicardial Radiofrequency Ablation of Therapy-Resistant Ventricular Arrhythmias: A Brief Case Series.

Despite extensive conventional endoepicardial ablation, significant intramural arrhythmogenic substrate may remain out of reach of unipolar radiofrequency ablation (RFA). The authors present clinical findings and procedural workflow for bipolar radiofrequency ablation (B-RFA) with 1 catheter placed against the endocardium and the other in the pericardial sac to ablate refractory ventricular arrhythmias. No serious adverse events occurred during B-RFA procedures, and the short-term and midterm clinical results were satisfactory. Optimal catheter choice and ablation parameters settings for B-RFA remain to be determined.

Atrial electrogram amplitude variability during atrial fibrillation ablation.

INTRODUCTION: Variability of the bipolar atrial electrogram amplitude may affect voltage maps created during ablation procedures, and thus also the extent of ablations. Therefore, the aim of the study was to assess the beat-to-beat electrogram amplitude variability in the left atrium in patients undergoing atrial fibrillation ablation. METHODS: In 11 patients undergoing ablation for atrial fibrillation, 362 mapping points were collected in two series. At each point, three consecutive beats were recorded and verified including the bipolar electrogram amplitude, contact force (CF), and orientation of the catheter tip. The repeatability and reproducibility of obtained measurements between consecutive beats and series were assessed by the Pearson correlation coefficient (r), the Bland-Altman test, repeatability coefficient (RC), relative standard deviation (RSD), and concordance correlation coefficient (CCC). RESULTS: A total of 1086 beats were analyzed. The correlation coefficient for bipolar atrial electrogram amplitude for the first two beats, and for the first and the third beats were 0.94 and 0.86, respectively. The average of differences between the first two beats and between the first and the third beats were 0.06 and 0.13 mV with 95% limits of agreement (LoA) within ±0.98 and ±1.74 mV, respectively. For CF values ≤5 and ≥20 g, the 95% LoA were narrower compared to other CF ranges and were ±0.49 and ±0.71 mV from the average value, respectively. When the analyzes were performed within the predefined ranges of bipolar electrogram amplitude: 0.05-1; 1-2; 2-3 mV, the 95% LoA were within ±0.33, ±0.98, and ±0.84 mV from the average value, respectively. RC and RSD were 1.41 mV and 20.8%, respectively. For repeated measurement between series, CCC ranged from 0.67 to 0.71 and the 95% LoA were within ±2.7 to 2.9 mV from the average value. CONCLUSION: Bipolar atrial electrogram amplitude recorded at a given site during ablation procedures is variable to an extent that may be clinically relevant. The magnitude of the observed variability is greater during remapping.

Forewarned Is Forearmed: Machine Learning Algorithms for the Prediction of Catheter-Induced Coronary and Aortic Injuries.

Catheter-induced dissections (CID) of coronary arteries and/or the aorta are among the most dangerous complications of percutaneous coronary procedures, yet the data on their risk factors are anecdotal. Logistic regression and five more advanced machine learning techniques were applied to determine the most significant predictors of dissection. Model performance comparison and feature importance ranking were evaluated. We identified 124 cases of CID in electronic databases containing 84,223 records of diagnostic and interventional coronary procedures from the years 2000-2022. Based on the f1-score, Extreme Gradient Boosting (XGBoost) was found to have the optimal balance between positive predictive value (precision) and sensitivity (recall). As by the XGBoost, the strongest predictors were the use of a guiding catheter (angioplasty), small/stenotic ostium, radial access, hypertension, acute myocardial infarction, prior angioplasty, female gender, chronic renal failure, atypical coronary origin, and chronic obstructive pulmonary disease. Risk prediction can be bolstered with machine learning algorithms and provide valuable clinical decision support. Based on the proposed model, a profile of 'a perfect dissection candidate' can be defined. In patients with 'a clustering' of dissection predictors, a less aggressive catheter and/or modification of the access site should be considered.

Simultaneous Entrainment Response Assessment at Multiple Sites.

BACKGROUND: The entrainment response, defined as the difference between the postpacing interval and the tachycardia cycle length (TCL) recorded from a mapping catheter, allows to track down the components of the tachycardia loop. OBJECTIVES: The aim of this study was to evaluate if the postpacing interval measured simultaneously from multiple sites that are remote from the pacing site (PPIR) could be clinically useful in mapping re-entrant circuits. METHODS: Ninety-two episodes of entrainment response in 29 patients with different macro-re-entrant tachycardias were evaluated using a standardized entrainment protocol. The spatial distribution of different values of PPIR-TCL in a simulation and a computational model of an entrained re-entrant tachycardia was also analyzed. RESULTS: The PPIR exceeded TCL by more than 20 milliseconds only if both pacing and recording sites were outside the tachycardia circuit. The PPIR-TCL at in-circuit sites was always ≤20 milliseconds. Sites with negative PPIR-TCL values were found either outside or inside the tachycardia circuit. CONCLUSIONS: Assessment of entrainment response from catheters remote from the pacing site may enhance spatial mapping of the tachycardia circuit. The PPIR-TCL above 20 milliseconds has an excellent positive predictive value in identifying sites outside the tachycardia circuit.

Safety and Efficacy of a Novel Blunt-Tip Concealed-Needle Epicardial Access Device: First-in-Human Feasibility Study.

Epicardial access is becoming increasingly important for various cardiovascular interventions. Access to dry pericardial space can be challenging and is often associated with significant complications. A novel concealed-needle blunt-tip device is designed to capture the parietal pericardium layer and retract it into the distal end of the device, which houses a fixated concealed needle, in a bid to minimize the likelihood of lacerating the visceral layer of the pericardium. This prospective single-arm study evaluated the feasibility of use of this device in 11 human subjects with successful access attained in 91% (10 of 11) of cases without adverse events. (Pericardial Access With ViaOne Device; NCT05006157).

A New Era in Epicardial Access for the Ablation of Ventricular Arrhythmias: The Epi-Co2 Registry.

OBJECTIVES: This multicenter registry aimed to assess the reproducibility and safety of intentional coronary vein exit and carbon dioxide insufflation to facilitate subxiphoid epicardial access in the setting of ventricular tachycardia ablation. BACKGROUND: Epicardial ablation for ventricular tachycardia is not a widespread technique due to the significant potential complications associated with subxiphoid puncture. The first experience in 12 patients showed that intentional coronary vein exit and carbon dioxide insufflation was technically feasible. METHODS: A branch of the coronary sinus was cannulated by means of a diagnostic JR4 coronary catheter. Intentional perforation at the distal portion of that branch was performed with a high tip load 0.014-inch angioplasty wire. A microcatheter was advanced over the wire into the pericardial space. Carbon dioxide was then insufflated into the pericardial space, allowing direct visualization of the anterior pericardial space to facilitate subxiphoid puncture. RESULTS: Intentional coronary vein exit was attempted in 102 consecutive patients in 16 different centers and successfully completed in 101 patients. Significant pericardial adhesions were confirmed in 3 patients, preventing carbon dioxide insufflation and epicardial ablation. None of the punctures were complicated with inadvertent right ventricular puncture or damage to a coronary artery. Significant bleeding (>80 ml) due to coronary vein exit occurred in 5 patients, without hemodynamic compromise. None of the patients required surgery. CONCLUSIONS: Coronary vein exit and carbon dioxide insufflation can be safely and reproducibly achieved to facilitate subxiphoid pericardial access in the setting of ventricular tachycardia ablation.

Results of a survey concerning atrial fibrillation ablation strategies in Poland.

BACKGROUND: Catheter ablation is an effective treatment for patients with atrial fibrillation (AF). Despite the increasing availability of the procedure, current treatment patterns of invasive AF treatment in Poland are unknown. AIMS: The aim of the study was to assess data on the contemporary approaches to AF ablation in Poland, such as: target population, patients' characteristics, ablation techniques, procedural results, and complication rates. METHODS: The survey including 36 questions was conducted among 38 representatives of Polish electrophysiology centers performing AF catheter ablation to test the methods and outcomes in their laboratories. RESULTS: The survey was conducted among 38 out of 69 Polish electrophysiology centers performing AF ablation. There were 88 ablation laboratories in 2018 in Poland. They have performed 16 566 ablations, of which 6680 were AF ablations, according to the Polish National Health Fund data. Therefore, 3745 AF ablations analyzed in this study constituted 22.6% of all ablations and 56% of AF ablations performed in Poland in 2018.Paroxysmal AF was the most common type of AF in all surveyed centers. In 69% of the centers, the preferred method was cryoballoon ablation and in 31%, radiofrequency point­by­point circumferential pulmonary vein isolation. The reported complication rate was low (6.4%), with localadverse events being the most frequent. The mean reported incidence of atrial flutter or tachycardia after ablation was low (5%). Repeated procedures were performed mainly with radiofrequency ablation (89%). Procedural techniques and the type of venous access did not vary between the centers. CONCLUSIONS: Paroxysmal AF was the most common indication for percutaneous ablation of that arrhythmia in Polish electrophysiology laboratories. The preferred method was cryoballoon ablation.

Distances between transseptal puncture site and anatomical landmarks.

The aim of the study was to provide quantitative data and to look for new landmarks useful during transseptal puncture (TSP) using a fluoroscopy-guided approach. METHODS AND RESULTS: A total of 104 patients at mean age 57 ± 12 years, of whom 92% underwent pulmonary vein isolation, were analysed. Before TSP catheters were placed in the coronary sinus (CS) and His bundle region. A guidewire running from femoral vein through great veins was left loose in superior vena cava. Before TSP X-ray images were taken in right anterior oblique (RAO) 45° and RAO 53° projections. Locations posterior to TSP site in RAO were described with negative values and those anterior with positive values. The measured distances in millimeters were as follows: (a) between TSP site and posterior atrial wall (RAO 45 = -21 ± 7 mm; RAO 53 = -19 ± 6 mm (b) between TSP site and free guidewire (RAO 45 = -5 ± 4 mm, RAO 53 = -3 ± 4 mm (c) between TSP site and CS ostium (RAO 45 = 9 ± 6 mm; RAO 53 = 8 ± 5 mm (d) between TSP site and His region (RAO 45 = 29 ± 8 mm; RAO 53 = 30 ± 8 mm). We observed correlations between measured distances and age, body mass index and sizes of cardiac chambers. The distance between TSP site and the line projected by the guidewire running between great veins, measured in mid-RAO projections, was very small. CONCLUSION: The distances between TSP site and standard anatomical landmarks used during TSP vary with regard to age, physique and cardiac chamber dimensions. TSP site, as assessed in mid RAO, is in direct vicinity to the line projected by a guidewire running between the great veins.

Bipolar ablation of epicardial posteroseptal accessory pathway.

We present a case of a 16-year-old male with WPW syndrome, referred for ablation after being resuscitated from cardiac arrest. Bipolar transseptal RF ablation successfully destroyed rapidly conducting epicardial posteroseptal accessory pathway after three failed attempts of endo- and epicardial ablation.

Clinical and echocardiographic parameters as risk factors for atrial fibrillation in patients with hypertrophic cardiomyopathy.

BACKGROUND: Atrial fibrillation (AF) is a common complication in patients with hypertrophic cardiomyopathy (HCM) and may contribute to high cardiovascular morbidity and mortality. Therefore, it is important to assess parameters associated with AF in HCM patients. HYPOTHESIS: The aim of the study was to evaluate AF prevalence in patients with HCM and to investigate risk factors for AF. METHODS: Five hundred and forty-six HCM patients aged below 65 were included into analysis. Clinical and echocardiographic parameters were analyzed. RESULTS: In 141 patients (25.8%) AF episodes were recorded. The following factors were identified as risk factors for AF in patients with HCM: age ≥ 45 years (OR 2.38, CI 1.40-4.05, P = 0.001), past history of presyncope or syncope (OR 2.25, CI 1.35-3.74, P = 0.002), non-sustained ventricular tachycardia (nsVT) (OR 2.70, CI 1.60-4.57, P < 0.001), left atrium diameter during first assessment (OR 1.065, CI 1.03-1.11, P = 0.001), left atrium diameter at the last assessment before AF occurrence (OR 1.10, CI 1.06-1.14, P < 0.001) and left ventricular ejection fraction at the last assessment before AF occurrence (CI 0.96, CI 0.94-0.98, P = 0.001). CONCLUSIONS: We confirm that AF is a common complication for patients with HCM. Identification of patients with high risk for AF and implementation of preventive strategies may reduce AF occurrence and its complications.

Ventricular fibrillation induced by radiofrequency energy delivery for premature ventricular contractions arising from the right ventricular outflow tract: is implantablecardioverterdefibrillator indicated?

INTRODUCTION    Inadvertently induced ventricular fibrillation (VF) by radiofrequency (RF) energy delivery for premature ventricular complexes (PVCs) is a rare phenomenon; nevertheless, it is crucial to assess long­term risk of sudden cardiac death in these patients. OBJECTIVES    The aim of our study was to define the long­term prognosis in patients with normal ejection fraction (EF), in whom VF was inadvertently induced by RF energy application during ablation of symptomatic idiopathic PVCs originating from the right ventricular outflow tract (RVOT). PATIENTS AND METHODS    Among over 20 000 RF catheter ablations performed at 5 tertiary centers (2008-2016), 6 patients (5 men) had VF induced by RF application to the RVOT. The mean (SD) age of patients was 35.2 (16.8) years. All patients had normal EF (≥60%). We analyzed the risk of malignant ventricular arrhythmias and assessed heart function during follow­up. RESULTS    After ablation, baseline contrast­enhanced magnetic resonance imaging was performed in 4 of the 6 patients; no area of late gadolinium enhancement was observed. One patient received an implantable cardioverter­defibrillator (ICD). Exercise tests revealed only rare PVCs. All patients completedthe follow­up (mean [SD] duration of follow­up, 64.0 [34.9] months). All patients were alive, with no cases of syncope, documented ventricular tachycardia, or VF. The patient with an ICD received 2 inappropriate high­voltage therapies. CONCLUSIONS    Patients with inadvertently induced VF via RF energy application during ablation of PVCs from the RVOT, who have normal left ventricular function and no electrocardiography abnormalities have good prognosis and low VF risk during long­term follow­up. Therefore, ICD placement seems to be not indicated for these patients.

Ablation of atrial tachyarrhythmias late after surgical correction of tetralogy of Fallot: long-term follow-up.

BACKGROUND: After the surgical correction of tetralogy of Fallot, surgical scars and natural obstacles form pathways capable of supporting an atrial tachyarrhythmia (AT). Radiofrequency (RF) ablation is effective, although the few studies published on this topic had relatively short follow-up periods. AIM: The aims of the study were to evaluate the acute and long-term effects of RF ablation of AT and examine the charac-teristics of arrhythmia recurrence. METHODS: Tetralogy of Fallot patients (n = 16, age 44.7 ± 10.7 years) referred for ablation of ATs, appearing 25.7 ± 9.6 years after repair, were studied. RESULTS: Twenty-five ATs were ablated, including 16 cavo-tricuspid isthmus atrial flutters (CTI-AFLs) and nine intraatrial reentrant tachycardia (IART). In one patient with paroxysmal atrial fibrillation (PAF), pulmonary vein isolation was also performed. Ten patients had permanent, and six had paroxysmal arrhythmia prior to the first ablation. Four patients had PAF. Regardless of the type of first ablated arrhythmia, all 16 patients required CTI-AFL ablation. The effectiveness of the first RF ablation reached 88%. The acute efficacy of RF ablation was 100% for CTI-AFL and 78% for IART. Long-term follow-up was possible in 15 out of 16 patients (mean follow-up 68.8 ± 36.6 months). Four patients were free of sustained arrhythmia, nine (60%) had AF. After the last RF ablation, an episode suggestive of CTI-AFL/IART was documented only in one patient. CONCLUSIONS: Ablation of CTI-AFL/IART in tetralogy of Fallot patients is safe and effective. AF was observed in most patients during the long-term follow-up. Regardless of the type of the first ablated arrhythmia, all patients required CTI-AFL ablation.

Characteristic features of patients with multiple accessory pathways.

Objective Only limited clinical and electrophysiological data concerning patients (pts) with multiple accessory pathways (MAP) in comparison to large control groups are available. The aim of our study was to analyse these data from the largest cohort of patients with multiple accessory pathways and a large control group. Method and results We analysed data from pts with MAP (group 1) and pts with a single accessory pathway (AP) (group 2) referred for radiofrequency catheter ablation (RFCA) at our tertiary centre. Group 1 consisted of 124 pts (M 62.10%, mean age 33.00 ± 5.26) with MAP and RFCA. Group 2 consisted of 376 pts (M 51.20%, mean age 35.87 ± 16.15) with a single accessory pathway and RF ablation. Group 1 exhibited a higher incidence of overt APs (P < 0.0001), Ebstein anomaly (P = 0.001), ventricular fibrillation (P = 0.012), antidromic atrioventricular re-entrant tachycardia (A AVRT) (P = 0.025) and male gender (P = 0.038). The mean age at the first documented atrioventricular re-entrant tachycardia (AVRT) episode was lower in pts with MAP than in pts with single APs: 16.79 ± 13.41 vs 20.84 ± 14.29, respectively (P = 0.001). Concealed accessory pathways (P < 0.0001) occurred more frequently in the control group. Group 1 had more right-lateral (P = 0.0001), mid-septal (P = 0.0001), left-posterior (P = 0.01), left-anterior (P = 0.013) and left-lateral localizations of AP (P < 0.037). Conclusions The MAP group included statistically significantly more men, Ebstein anomaly and overt APs. The mean age of the first episode of atrioventricular re-entrant tachycardia was lower in pts with MAP. Certain distribution patterns are apparent for single and MAP. Pts with MAP are at higher risk of VF and antidromic atrioventricular re-entrant tachycardia.

Risk factors of atrial fibrillation recurrence despite successful radiofrequency ablation of accessory pathway: At 11 years of follow-up.

BACKGROUND: Previous reports on patients with radiofrequency catheter ablation (RFCA) of accessory pathway (AP) and atrial fibrillation (AF) include only short follow-up periods. The aim of this study was to analyze predictors of recurrence of AF in patients after successful RFCA of APs over long term follow-up periods. METHODS: Of the 1,007 patients who underwent non-pharmacological treatment of APs (between the years 1993-2008), data of 100 consecutive patients were retrospectively analyzed (75 men, mean age 43.6 ± 14.7), with the longest period of follow-up (mean 11.3 ± 3.5 years) after successful RFCA of AP. In Group 1, there were 72 patients (54 men, mean age 40.66 ± 13.85 years) without documented episodes of AF after RFCA of AP. Group 2 consisted of 28 patients (21 men, mean age 50.79 ± 14.49 years) with AF episodes despite successful elimination of AP. RESULTS: In univariate analysis, patients from Group 1 were significantly younger at the time of abla-tion than patients from Group 2 (40.66 ± 13.85 vs. 50.79 ± 14.49 years; p = 0.002), had shorter his¬tory of AF episodes (4.11 ± 4.07 vs. 8.25 ± 7.50 years; p = 0.024) and had less frequently documented atrial tachycardia (AT) prior to ablation (3.39 vs. 20.00% years; p = 0.022). In multivariate analysis, the history of AF in years (p = 0.043), was an independent risk factor for AF recurrences. CONCLUSIONS: Older patient age, longer history of AF and AT prior to RFCA of APs identified a sub-group of patients who required additional treatment. In the multivariate analysis, the history of AF in years (p = 0.043) was a risk factor for AF recurrence.

Radiofrequency catheter ablation of accessory pathways in patients with Ebstein's anomaly: At 8 years of follow-up.

BACKGROUND: Data regarding long-term follow-up of radiofrequency catheter ablation (RFCA) of accessory pathways (APs) in patients with Ebstein's anomaly (EA) are limited. The procedures are challenging due to multiple or wide APs. METHODS: Analysis was performed on clinical and periprocedural data of patients with EA referred to the centre in order to perform catheter ablation of AP. The group consisted of 22 patients (female 40.9%, mean age 33.6 ± 19.1 years). The follow-up utilized electrocardiogram and Holter monitoring. RESULTS: Twenty-two patients had 33 accessory pathways (8 patients had multiple APs, 11 patients broad AP). Twenty-nine different arrhythmias were ablated: 20 orthodromic atrioventricular reciprocating tachycardia (O-AVRT), 5 antidromic atrioventricular reciprocating tachycardia (A-AVRT), 3 slow/ fast atrioventricular nodal reentry tachycardia (s/f AVNRT) and 1 cavotricuspid-isthmus-dependent atrial flutter (CTI-AFL). In 3 (13.6%) patients multiple ablation targets for RFCA ablation were observed. The acute procedural success rate after the first RFCA performed was: 100% for AVNRT, 77.3% for APs and 50.0% for CTI-AFL ablation. Follow-up (mean 95.7 ± 49.8 months) was completed in 86.4% of patients. One patient had paroxysmal atrial fibrillation not targeted during ablation. One patient died due to heart failure 12 years after RFCA. Three patients who underwent RFCA of accessory pathways in the mid-1990s were lost in follow-up. CONCLUSIONS: Radiofrequency ablation in patients with EA is challenging but safe and have a high short-term as well as long-term success rate.