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The study explored the performance of hybrid and population rye (Secale cereale) cultivars under two different crop management intensities in Poland: moderateintensity and high-intensity management. The focus was grain yield, grain quality, yield components, and variety stability in two growing seasons (2018/2019 and 2019/2020) at three locations. Hybrid cultivars consistently yielded higher grain yields (9.81 t ha−1) than population cultivars (7.90 t ha−1), with increase of 24.9%. However, hybrid cultivars had lower protein content (8.94%) than population cultivars (9.77%). Spike number was the most influential factor on yield, followed by 1000-grain weight and grains per spike, regardless of cultivar type. Hybrid cultivars displayed a lower degree of stability as assessed using the ranking sum of the Shukla variance and the multi-trait stability index. Hybrid cultivars were strongly dependent on resistance to fungal diseases, including Septoria (Mycosphaerella graminicola), and increased stability under moderate-intensity management. Resistance to soil acidification became more important for cultivar stability under high-intensity management [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Catheter ablation (CA) is a preferred treatment for atrial fibrillation (AF), often outperforming antiarrhythmic medications in maintaining sinus rhythm and managing symptoms. One of the most important features of any treatment method, alongside its effectiveness, is its safety., Methods: This study evaluates 180-day all-cause mortality rates post-ablation using data from the National Health Fund in Poland (NHF-P), encompassing over 99% of AF CAs and 100% of deaths in Poland from 2012 to 2019., Results: Our analysis, which included 31,214 ablations on 26,767 patients (34.8% female), compared cryoballoon and radiofrequency (RF) ablation techniques and assessed mortality rates and risk factors. The study revealed a 180-day mortality rate of 0.56%, with the highest rate observed in patients over 80 years old (2.67%) and the lowest in those aged 18-34 years (0.29%). Mortality did not significantly differ between cryoballoon (0.48%) and RF ablation (0.65%; p = 0.072). The risk of mortality did not differ between patients undergoing a first-time ablation and those having subsequent procedures (p = 0.90, OR 0.92). Significant risk factors for increased mortality included male sex, kidney disease, heart failure, diabetes, prior myocardial infarction, and a history of malignancy., Conclusion: The 180-day mortality rate after AF ablation procedure reached 0.56%, with no significant difference between cryoballoon and RF ablation. Further research, including matched control groups and extended follow-up periods, is essential to better understand the benefits and risks of CA for AF, particularly in the oldest patient groups., (© 2025 Wiley Periodicals LLC.)

Introduction: Stability of catheter-tissue contact in the robotic magnetic navigation (RMN) system is one of the key features that distinguishes this system from manually guided catheters. Numerous studies have shown that contact force (CF) in manually controlled catheters is as crucial for forming an optimal lesion as the duration of application or power. Catheters used in the RMN system lack a quantitative method for intraoperative monitoring of this parameter. Our study aims to partially address this gap in scientific knowledge., Methods: We conducted a total of 1200 CF measurements using the RMN system (Stereotaxis, St. Louis, MO, USA), a magnetic-guided 8 Fr RF ablation catheter (THERMOCOOL RMT Catheter, Biosense Webster, Irvine, CA, USA) inserted through a long sheath (SR0, Abbott Cardiovascular, Nathan Lane North, Plymouth, MN, USA), and a precision jewelry scale (IKEME, Guangdong, CN). We analyzed the impact on the obtained CF values of four different magnetic field vectors (transverse, sagittal, caudal, and cranial), two field strengths (0.1T and 0.08T), and three catheter extension configurations from the long sheath (with Position 1 being the least extended and Position 3 the most extended)., Results: The contact force values varied significantly across the different magnetic field vectors, field strengths, and catheter extensions from the vascular sheath. The greatest differences in achieved values were observed across the different magnetic field vectors in the Position 1, ranging from 3.52 ± 0.1 g (caudal plane) to 15.15 ± 0.05 g (cranial plane) at 0.08 Tesla (T) field strength (p < 0.001), and from 4.10 ± 0.06 g (caudal) to 15.01 ± 0.07 g (cranial) at 0.1 T, p < 0.001. Differences in other vectors reached approximately 20%. The highest CF values were obtained in Position 1, intermediate values in Position 2, and the lowest in Position 3. An exception was the transverse vector, where, particularly with a magnetic field of 0.1 T, more similar values were observed across Positions 1-3, with respective values of 8.61 ± 0.14 g, 9.36 ± 0.06 g, and 8.31 ± 0.05 g. A stronger magnetic field (0.1 T compared to 0.08 T) resulted in higher CF values, especially during measurements in the transverse vector. This effect was most pronounced in the most extended catheter from the sheath - Position 3 (with respective values of 4.54 ± 0.09 g vs. 8.31 ± 0.05 g, p < 0.001). In the sagittal, cranial, and caudal vectors, the differences were less noticeable., Conclusion: Different magnetic field vectors, catheter extensions from the sheath, and magnetic field strengths result in varying contact force values. For effective radiofrequency ablation lesions, these factors should be considered alongside power, duration, and other established parameters., (© 2025 Wiley Periodicals LLC.)

Background/Objectives: Electrographic flow (EGF) mapping allows for the visualization and quantification of atrial fibrillation (AF) wavefront propagation patterns. EGF-identified sources were shown in the randomized controlled FLOW-AF trial to significantly increase the likelihood of AF recurrence within 1 year if left unablated. Electrographic flow consistency (EGFC) additionally measures the stability of observed wavefront patterns, such that patients with more organization have a healthier substrate and lower recurrence. Source presence and EGFC can be used collectively to assign mechanistic phenotypes to AF patients. Methods: The patient phenotypes, treatment modalities, and outcomes in FLOW-AF were compared with those of patients in the ensuing AF-FLOW Global Registry , which was conducted by separate physicians at discrete clinical centers. Results: Patients with low EGFC (≤0.62) had a 12-month freedom from AF (FFAF) of 46%, while those with a high mean EGFC (>0.62) had a FFAF of 81%. Right atrial EGFC was correlated with left atrial EGFC, and the highest recurrence occurred in those with biatrial low EGFC. Source presence also affected the recurrence rates in both trials, such that the presence of EGF-identified sources in PVI-only patients lowered the FFAF from 65% to 36%, but the elimination of sources produced a 30% absolute increase in FFAF from 36% to 66%. Conclusions: Patient outcomes by EGF-based AF phenotype were consistent across two cohorts of patients from separate clinical trials at distinct centers. Patients with a high EGFC and no sources post-procedure had the best outcomes. EGF mapping provides insights into underlying disease pathophysiology and may be employed prospectively to predict recurrence.

Background: Electrographic flow (EGF) mapping allows for the visualization of global atrial wavefront propagations. One mechanism of initiation and maintenance of atrial fibrillation (AF) is stimulation from EGF-identified focal sources that serve as driver sites of fibrillatory conduction. Electrographic flow consistency (EGFC) further quantifies the concordance of observed wavefront patterns, indicating that a healthier substrate shows more organized wavefront propagation and higher EGFC. Freedom from AF (FFAF) recurrence has accordingly been shown to be higher in patients with ablated vs. unablated sources and with high vs. low EGFC., Objectives: (1) Measure FFAF across EGF-derived phenotypes in patients enrolled in the AF-FLOW Global Registry; (2) determine if a relationship exists between EGFC and percentage of healthy voltage as measured from bipolar voltage maps., Methods: The AF-FLOW Global Registry is a multicenter, prospective study of 25 all-comer AF patients who underwent concomitant high-density bipolar voltage mapping with a 16-electrode grid mapping catheter and EGF mapping with a 64-pole basket catheter. The EGF algorithm detects extra-pulmonary vein sources as origins of excitation from a singularity of divergent flow vectors and was used to localize RF ablation targets. Overall, EGFC per atrium was also computed as the average of the modulus of individual EGF vectors, where the vector length represents the consistency of flow patterns. Patients were then assigned phenotypes on the basis of source presence or absence and EGFC, and rates of FFAF at 1-year were compared across the four resulting phenotypes. Atrial EGFC was also compared to the percentage of healthy tissue determined by bipolar voltage mapping., Results: Patients with paroxysmal AF had higher FFAF than persistent AF (PeAF) and long-standing PeAF patients; patients receiving de novo ablation had higher FFAF than those receiving redo ablation. Patient phenotyping revealed that those with high EGFC had higher FFAF than those with low EGFC (p = 0.015). Atrial EGFC was also correlated to the percent of high voltage tissue across all patients (r = 0.651, p < 0.0001)., Conclusions: EGF mapping provides insights into the mechanistic nature of AF and the atrial health of the underlying substrate. Therefore, further studies are needed to develop phenotype-specific treatments for the disease., Trial Registration: ClinicalTrials.gov identifier: NCT05481359., (© 2025 The Author(s). Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Introduction: Atrial fibrillation (AF) is the most common sustained arrhythmia, and catheter ablation (CA) is a primary therapeutic option. However, the 30-day all-cause mortality risk associated with CA for AF may be underestimated due to selection bias. Our study aimed to assess 30-day mortality in an unselected cohort of patients., Methods: Data from the National Health Fund-Poland covered over 99% of nationwide radiofrequency ablation (RF) or cryoballoon ablation for AF, with 100% recorded deaths. The study included consecutive CA procedures in adult patients between 2012 and 2019. Thirty-day mortality rates were calculated for each age group., Results: A total of 31 214 CAs for AF were performed on 26 767 patients (34.8% female). Forty-four percent of patients had hypertension, 31.2% had coronary artery disease, 14.4% had heart failure, 11% had diabetes mellitus, 5.6% had malignant neoplasms, 2.7% had a previous myocardial infarction, 2.5% had a previous stroke, and 2.2% had kidney disease. Thirty-two deaths (0.1%) occurred within 30 days, with the highest mortality in the oldest age group (>80 years). Statistical analysis revealed higher incidences of kidney disease (p < 0.001) and heart failure (p = 0.001) in patients who died within 30 days. Mortality risk did not significantly differ between cryoballoon and RF ablation, as well as first and subsequent ablation for AF. The risk of death within 7 days postablation for AF was 1 in 2750 procedures, while the risk of death on the same day postablation was 1 in 6250 procedures., Conclusions: The 30-day mortality rate in a large, unselected AF ablation cohort, covering 99% of procedures in the country, is low except for the oldest patients. This factor should be taken into consideration when offering CA for AF., (© 2024 Wiley Periodicals LLC.)

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.

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., (© 2022 Wiley Periodicals LLC.)

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.

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 point‑by‑point 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.

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., (© 2019 Wiley Periodicals, Inc.)

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., (© 2019 Wiley Periodicals, Inc.)

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., (© 2018 Wiley Periodicals, Inc.)

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 long‑term risk of sudden cardiac death in these patients. OBJECTIVES    The aim of our study was to define the long‑term 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 follow‑up. RESULTS    After ablation, baseline contrast‑enhanced magnetic resonance imaging was performed in 4 of the 6 patients; no area of late gadolinium enhancement was observed. One patient received an implantable cardioverter‑defibrillator (ICD). Exercise tests revealed only rare PVCs. All patients completedthe follow‑up (mean [SD] duration of follow‑up, 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 high‑voltage 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 long‑term follow‑up. Therefore, ICD placement seems to be not indicated for these patients.

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.

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.

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.

Background: Re-entrant atrial arrhythmias are common in patients after cardiac surgery. To date, however, no studies have reported the safety and efficacy of radiofrequency (RF) ablation of macro-re-entrant atrial arrhythmias in a unique, homogeneous group of patients after surgical replacement of the aortic valve and single right atriotomy., Methods: Among over 4,000 RF catheter ablations performed at the authors' center between 2008 and 2014, eight patients (seven males, one female; mean age 55.1 ± 19.9 years) after aortic valve replacement (AVR) and without history of any other cardiosurgical procedures were identified with documented macro-re-entrant atrial arrhythmia. The mechanism of macro-re-entrant arrhythmia was analyzed, as well as the safety and efficacy of RF ablation in a group of patients after AVR and single right atrial free wall atriotomy., Results: The average time from surgery to RF catheter ablation was 11.3 ± 11.3 years (range: 4-35 years). In five patients with permanent arrhythmia, entrainment mapping proved these arrhythmias to be cavotricuspid isthmus- dependent, in three patients with paroxysmal atrial arrhythmia cavotricuspid isthmus-dependent atrial flutter was induced during the electrophysiological study. Intra-atrial re-entrant tachycardia was neither recorded nor induced in any patient. Successful ablation of cavotricuspid isthmus is defined as the termination of arrhythmia, and bidirectional block in cavotricuspid isthmus was achieved in all patients. A long-term follow up, based on a seven-day Holter monitoring, was conducted in all patients, with a mean observation time of 40.1 ± 28.6 months after the procedure. Among the patients, ablated arrhythmia (cavotricuspid isthmusdependent atrial flutter) recurred in one patient, atrial fibrillation occurred in three patients, and an atrial tachycardia in one patient., Conclusions: In the presented series of patients, cavotricuspid isthmus-dependent atrial flutter was shown to be the mechanism of post-cardiosurgical macro-re-entrant clinical arrhythmia in all subjects. Atrial fibrillation was frequently observed among those patients during follow up.

Background: Atrial tachyarrhythmias are a leading source of morbidity and mortality after Fontan-type procedures and antiarrhythmic drug therapy is often ineffective in these patients., Aim: To evaluate short- and long-term outcomes of radiofrequency current ablation for atrial tachycardia (AT) in patients after the Fontan procedure, and to report clinical, electrophysiological and electroanatomical characteristics of these arrhythmias., Methods: We retrospectively analysed data obtained in 8 patients (5 males, 3 females) after the Fontan procedure who underwent ablation for AT between 2002 and 2013. In order to compare the clinical impact of arrhythmia before and after ablation, we used the modified arrhythmia score, ranging from 0 (no arrhythmia activity) to 12 (very severe arrhythmia). In all patients, electroanatomical mapping using the CARTO system was performed, allowing semiquantification of low-voltage (< 0.5 mV) areas and scars., Results: Seven patients had an atriopulmonary connection and 1 patient had an extracardiac conduit. The mean patient age was 9.4 ± 3.1 years at the time of the Fontan procedure and 26.2 ± 4.6 years at the time of the first ablation. A total of 18 ablations were performed with no complications, 1 to 4 (median 2.5) procedures per patient. In patients who had more than 1 ablation, the mean time from the first to the last procedure was 34.8 months (range 1-64 months). In individual patients, 1 to 4 (median 2.5) different ATs were observed, with the mean tachycardia cycle length of 334 ± 95 ms. In 6 patients, low-voltage area (< 0.5 mV) comprised 25-50% of the right atrium, and in two others it comprised 10-25% and < 10% of the right atrium, respectively. Seven procedures were fully successful (ablation of all ATs), 7 were partially successful (ablation of only some AT, including clinical arrhythmia, but not of all ATs) and 4 were unsuccessful (failed ablation of clinical AT). The mean procedural, fluoroscopy and ablation times were 176 ± 54.6, 13.7 ± 5.7 and 21.7 ± 11.9 min, respectively. Freedom from arrhythmia during the mean follow-up of 58.6 ± 46 months (range 11-127 months) since the last procedure was obtained in 4 patients. The median arrhythmia score after the last ablation was significantly reduced compared to baseline (4.5 vs. 8; p < 0.05)., Conclusions: Catheter ablation of AT in patients after the Fontan procedure is safe but its acute and long-term efficacy is limited. Due to complex and extensive substrate, along with complex anatomy, recurrences are frequent and patients may require repeat ablation procedures. Suppression of arrhythmia is associated with an improved clinical status of the patients.