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Background: The inspIRE study (Study for Treatment of Paroxysmal Atrial Fibrillation [PAF] by Pulsed Field Ablation [PFA] System With Irreversible Electroporation [IRE]) evaluated safety and effectiveness of a fully integrated biphasic pulsed field ablation (PFA) system with a variable-loop circular catheter for the treatment of drug-refractory paroxysmal atrial fibrillation.Methods: Subjects underwent pulmonary vein (PV) isolation with the PFA system, using at least 12 applications per vein; adenosine/isoproterenol was administered to confirm entrance block. Wave I assessed initial safety, including for esophageal lesions, silent cerebral lesions, and PV stenosis. Wave II (pivotal phase) tested (1) primary safety, incidence of early-onset primary adverse events, and (2) primary effectiveness, confirmed PV isolation with freedom from documented atrial arrhythmia at 12 months. The study design specified an interim analysis to determine early success once 30 subjects reached the 12-month follow-up and all subjects reached 3-month follow-up.Results: Across 13 centers in Europe/Canada, 226 subjects were enrolled, met criteria for safety and effectiveness evaluations, and received PFA (Wave I, 40; Wave II, 186). Wave I demonstrated no esophageal thermal lesions or PV stenosis. Among 39 subjects with cerebral magnetic resonance imaging, silent cerebral lesions were detected in 4 of the first 6 subjects, after which workflow enhancements, including a 10-second pause between PFA applications, were implemented; subsequently, only 4 of 33 subjects had silent cerebral lesions. In the Wave II phase, no primary adverse events were reported. Upon declaring early success, 83 subjects reached 12-month follow-up. With 100% entrance block, PV isolation without acute reconnection was achieved in 97.1% of targeted veins. For Wave II, the primary effectiveness end point per Kaplan-Meier at the time of interim analysis was 70.9%; 12-month freedom from symptomatic atrial fibrillation/atrial flutter/atrial tachycardia recurrence and repeat ablation was 78.9% and 92.3%, respectively. Total procedure and transpired PFA times were 70.1 +/- 27.7 and 26.7 +/- 14.0 minutes, respectively.Conclusions: The inspIRE trial confirmed the safety and effectiveness of the novel mapping-integrated PFA system. The authors would like to express their deepest gratitude to all investigators, including coinvestigators and guest operating investigators. They wish to thank the following individuals for their support in trial design, execution, statistical analysis, medical writing, and additional value to developing the manuscript: Carmen Rousseeuw, Sarah Rabau, Liesbeth Vanderlinden, Lee Ming Boo, Christina Kaneko, Jaclyn Alcazar, Tara Gomez, Tiffany Tan, Melissa Mert, Guixia Huang, Xiaoxue Gu, Puneet Jatana, Rebecca Beals, and Dror Berman (all employees of Biosense Webster, Inc.). Michelle Hughes, Bsc, with Lumanity Communications Inc (Yardley, PA), provided medical writing and editorial support, in accordance with Good Publication Practice guidelines, which were funded by Biosense Webster, Inc, under direction of the authors.

Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.

BACKGROUND: Contact force (CF)-guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after 3 months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Our objective is to study recurrent atrial arrhythmia during 12-month follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA.METHODS: Patients were randomised 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥ 30 s within 12 months and documented in 12-lead ECG or Holter monitor recording.RESULTS: We included 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in final analysis. Recurrent arrhythmia was detected in 36 of 77 (47%) patients in the intervention group, and 32 of 73 patients (44%) in the control group (p = 0.51). Atrial fibrillation was detected in 23 (30%) and 29 (40%) patients in the intervention and control groups respectively. AFL was detected in 11 (14%) and 5 (7%) patients in the intervention and control groups respectively.CONCLUSIONS: Contact force-guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-month follow-up as compared with ablation blinded for contact force.

Contact force (CF)-guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after 3 months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Our objective is to study recurrent atrial arrhythmia during 12-month follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA.Patients were randomised 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥ 30 s within 12 months and documented in 12-lead ECG or Holter monitor recording.We included 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in final analysis. Recurrent arrhythmia was detected in 36 of 77 (47%) patients in the intervention group, and 32 of 73 patients (44%) in the control group (p = 0.51). Atrial fibrillation was detected in 23 (30%) and 29 (40%) patients in the intervention and control groups respectively. AFL was detected in 11 (14%) and 5 (7%) patients in the intervention and control groups respectively.Contact force-guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-month follow-up as compared with ablation blinded for contact force.

Background: Contact force (CF) guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after three months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Objective: To study recurrent atrial arrhythmia during 12-months follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA. Method: Patients were randomized 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥30 seconds within 12 months, symptomatic or asymptomatic and documented in 12-lead ECG or Holter monitor recording. We did intention-to-treat (ITT) analysis. Results: We included and randomized 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in ITT-analysis, in which recurrent arrhythmia was detected in 47 (31%) patients, 25 in the intervention group and 22 in the control group (p = 0.25). Atrial fibrillation was detected in 38 patients (18 versus 20 patients), and AFL in the remaining 9 patients (7 versus 2 patients). Conclusion: Contact force guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-months follow-up as compared with ablation blinded for contact force.

Background: Poor outcome after atrial tachycardia (AT) radiofrequency catheter ablation (RFCA) in repaired congenital heart disease (CHD) has been attributed to CHD complexity. This may not apply to contemporary patients. The objective of our study was to assess outcome after RFCA for AT in contemporary patients with CHD according to prior atrial surgery and predefined procedural endpoints. Methods: Patients with CHD referred for AT RFCA to 3 European centers were classified as no atrial surgery/cannulation only, limited or extensive prior atrial surgery. Procedural success was predefined as termination and nonreinducibility for focal AT and bidirectional block across ablation lines for intra-atrial reentrant tachycardia and after empirical substrate ablation for noninducible patients. Patients were followed for AT recurrence and mortality. Results: Ablation was performed in 290 patients (41±17 years, 59% male; 3-dimensional mapping 89%, irrigated tip catheters 90%, transbaffle access 15%). In 197, 233 AT were targeted (196 intra-atrial reentrant tachycardia [64% cavotricuspid (mitral) isthmus–dependent, 33% systemic-venous incision–dependent] and 37 focal AT). In 93 noninducible patients, empirical substrate ablation was performed. Procedural success was achieved in 209 (84%) patients. AT recurred in 148 (54%) 10 (interquartile range, 0–25) months after RFCA. AT-free survival was significantly better in patients with no atrial repair/cannulation only and in patients with complete procedural success independently of CHD complexity. From 94 patients undergoing reablation, the initially targeted substrate had recovered in 64%. Conclusions: In contemporary patients with CHD, outcome after AT ablation is associated with presence of prior atrial surgery and achievement of predefined procedural endpoints rather than CHD complexity. Techniques to improve lesion durability are likely to further improve long-term outcome.

Objectives This study sought to evaluate the value of combined electrogram (EGM) information provided by simultaneous mapping using micro- and conventional electrodes in the identification of post–myocardial infarction ventricular tachycardia substrate. Background Ventricular tachycardias after myocardial infarction are related to scars with complex geometry. Scar delineation and ventricular tachycardia substrate identification relies on bipolar voltages (BV) and EGM characteristics. Early reperfusion therapy results in small, nontransmural scars, the details of which may not be delineated using 3.5 mm tip catheters. Methods Nine swine with early reperfusion myocardial infarction were mapped using Biosense Webster’s QDOT Micro catheter, incorporating 3 microelectrodes at the tip of the standard 3.5 mm electrode. Analysis of EGM during sinus rhythm, right ventricular pacing, and short-coupled right ventricular extrastimuli was performed. The swine were sacrificed and mapping data were projected onto the heart. Transmural biopsies (n = 196) corresponding to mapping points were obtained, allowing a head-to-head comparison of EGM recorded by micro- and conventional electrodes with histology. Results To identify scar areas using standard electrodes, unique cutoff values of unipolar voltage Conclusions The combined information provided by multisize electrode mapping increases the sensitivity with which areas of scar are identified. EGM from microelectrodes, with narrower spacing, allow identification of near-fields arising from thin subendocardial layer and layers activated with short delay obscured in EGM from conventional mapping catheter.

Aims Contact force (CF) between radiofrequency (RF) ablation catheter and myocardium and ablation index (AI) correlates with RF lesion depth and width in normal-voltage (>1.5 mV) myocardium (NVM). We investigate the impact of CF on RF lesion depth and width in low ( Methods and results Twelve weeks after myocardial infarction, 10 pigs underwent electroanatomical mapping and endocardial RF ablations were deployed in NVM, IVM, and LVM myocardium. In vivo ncMRI was performed before the heart was excised and subjected to gross anatomical evaluation. Ninety (82%) RF lesions were evaluated. Radiofrequency lesion depth and width were smaller in IVM and LVM compared with NVM (P Conclusions Radiofrequency lesions deployed by similar duration, power and CF are smaller in IVM and LVM than in NVM. Radiofrequency lesion depth and width correlated with CF, AI, and impedance drop in NVM and IVM but not in LVM. Native contrast magnetic resonance imaging may be useful to assess RF lesion depth and width in NVM, IVM, and LVM.

OBJECTIVES: Left atrial flutter has been reported in up to 10% of patients following pulmonary vein isolation or cardiac surgery. Left atrial flutter is typically highly symptomatic, responds poorly to medical antiarrhythmic treatment, and is often treated by catheter ablation. We aimed to investigate midterm freedom from recurrent arrhythmia after catheter ablation for left atrial flutter.DESIGN: In the National Danish Ablation Registry, we identified consecutive patients, who had undergone catheter ablation for left atrial flutter between 1 January 2014 and 1 April 2017 at our centre.RESULTS: A total of 53 patients (median age 68 years (IQR 60-71) 37 (70%) male) were included. Forty-two patients had prior left atrial catheter ablation procedures (79%), one patient prior ablation for classic atrial flutter (2%), four patients had prior surgery for congenital heart disease (8%), and six patients (11%) had no previous cardiac intervention. Acute procedural success, defined as non-inducibility of any atrial arrhythmia, was achieved in 45 of 53 patients (85%). During midterm follow-up (mean 20 ± 12 months), 26 patients experienced an episode of recurrent atrial arrhythmia. Median EHRA-score was 3 (range 2-4) before catheter ablation and reduced to median 1 (range 1-3) evaluated at follow-up visits after three and twelve months (both p CONCLUSION: Left atrial flutter is preceded by catheter ablation or cardiac surgery in 89% of patients. Acute procedural success is achieved in majority of patients and ablation reduces symptoms effectively. During midterm follow-up, almost half the patients experience recurrent atrial arrhythmia.

OBJECTIVES: We aimed to investigate the predictors of recurrent arrhythmia after repeated pulmonary vein isolation (PVI) performed in the era of contact force without additional substrate ablation. One of the predictors studied, ablation index (AI), incorporates power, contact force, and time in a weighted formula and is reported to predict lesion size in animals. Design. Consecutive patients (n = 108) undergoing repeat PVI without additional substrate modification using a contact force sensing catheter were included retrospectively at a tertiary center. All ablation points were analyzed offline. A new variable, normalized AI (AI corrected for the location of the lesion-anterior vs. posterior) was calculated. The patients were systematically followed with clinical visit and 12-lead ECG as well as review of the regional electronic patient files at 3 and 12 months after the procedure with 5-day Holter at 12 months. Results. Electrical reconnection to at least one pulmonary vein (PV) was seen in 97% of the patients. The recurrence rate was 35%. There was no recurrence in patients with nAI above 1.15 (n = 26). Patients with electrical reconnection of up to two PVs had a higher risk of recurrence compared with patients having electrical reconnection of three or four PVs (p = .003), and this risk was especially high in patients with persistent atrial fibrillation (69 [39-91]%). Conclusions. The risk of recurrence is higher in patients with ablations performed with low levels of AI and in patients with reconnection to up to two PVs. Our data may indicate the need for higher target levels of AI during repeat PVI than normally used during de-novo PVI.

Background: A novel QDOT MICRO (Biosense Webster, Inc., Irvine, CA) catheter with optimized temperature control and microelectrodes was designed to incorporate real-time temperature sensing with contact force detection and microelectrodes to streamline ablation workflow. The QDOT-MICRO feasibility study evaluated the workflow, performance, and safety of temperature-controlled catheter ablation in patients with symptomatic paroxysmal atrial fibrillation with conventional ablation setting.Methods: This was a non-randomized, single-arm, first-in-human study. The primary outcome was pulmonary vein isolation (PVI), confirmed by entrance block after adenosine and/or isoproterenol challenge. Safety outcomes included incidences of early-onset primary adverse events (AEs) and serious adverse device effects (SADEs). Device performance was evaluated via physician survey.Results: All evaluated patients (n = 42) displayed 100% PVI. Two primary AEs (4.8%) were reported: 1 pericarditis and 1 vascular pseudoaneurysm. An additional SADE of localized infection was reported in 1 patient. No stroke, patient deaths, or other unanticipated AEs were reported. Average power delivered was 32.1±4.1 W, with a mean temperature of 40.8°C±1.6°C. Mean procedure (including 20-minute wait), fluoroscopy, and radiofrequency application times were 129.8, 6.7, and 34.0 minutes, respectively. On device performance, physicians reported overall satisfactory performance with the new catheter, with highest scores for satisfaction and usefulness of the temperature indicator.Conclusions: Initial clinical experience with the novel catheter showed 100% acute PVI success and acceptable safety and device performance in temperature-controlled ablation mode. There were no deaths, stroke, or unanticipated AEs. Fluoroscopy and procedural times were short and similar or better than reported for prior generation catheters.

OBJECTIVES: Recurrent arrhythmia after pulmonary vein isolation (PVI) by radiofrequency (RF) ablation in patients with atrial fibrillation (AFIB) remains a significant challenge. Using contact force (CF) sensing ablation catheters, we aimed to identify procedure related parameters associated with recurrence after de-novo PVI in patients with AFIB.METHODS: Consecutive patients undergoing a de-novo PVI procedure (n = 120, 63% paroxysmal and 37% persistent AFIB) employing a force-sensing ablation catheter were included. A clinical control including electrocardiogram and 120 hour of Holter-recording at 12-months was performed in all patients. Recurrence was defined as any documented AFIB or atrial flutter more than 30 seconds on Holter-recording after an initial blanking period of three months.RESULTS: Recurrence occurred in 44 patients (37%). Mean CF was lower in patients with recurrent arrhythmia (22.2 ± 9.5 vs. 28.8 ± 9.3 g, p CONCLUSIONS: Low CF and dragging during ablation as compared with point-by-point ablation technique were associated with recurrent arrhythmia in patients with AFIB undergoing de-novo PVI by RF ablation.

To investigate the effect of the operator knowing the real-time contact force (CF) on the efficacy of pulmonary vein antrum isolation (PVAI).Fifty patients with paroxysmal atrial fibrillation (AF) or short lasting persistent AF were randomized to CF guided PVAI (n = 25) or conventional PVAI (n = 25). In the CF guided group, CF between 10 and 40 g was aimed at. Efficacy of PVAI was measured as reduction in AF burden (AFB) and time to AF recurrence detected by implantable cardiac monitor (ICM), inserted three months before PVAI. Blanking period was three months and follow-up 12 months.All pulmonary veins were isolated in the CF guided group and all but one in the conventional group. Mean CF was 25 g in the CF guided group and 24 g in the conventional group (p = 0.75). Compared to pre-ablation, median [IQR] relative reduction in AFB 3-12 months after ablation was 100 [99-100]% in the CF guided group (p 0.001) and 99.4 [25-100]% in the conventional group (p 0.001), not different between groups (p = 0.09). Nine patients (36%) had AF recurrence in the CF guided group and 13 (52%) in the conventional group (p = 0.21, log-rank test). CF differed between operators. When adjusted for operator by regression analysis, patients without recurrent AF had lower proportion of ablation time with CF10 g than recurrent patients (p = 0.034). No complications occurred.Operator knowledge of real-time CF had no significant effect on AFB reduction or time to AF recurrence. Larger trials should be done to study benefit of real-time CF.

Aims Contact force (CF) sensing has emerged as a tool to guide and improve outcomes for catheter ablation (CA) for cardiac arrhythmias. The clinical benefit on patient outcomes remains unknown. To study whether CF-guided CA for typical atrial flutter (AFL) is superior to CA not guided by CF. Methods and results In a double-blinded controlled superiority trial, we randomized patients 1:1 to receive CA for typical AFL guided by CF (intervention group) or blinded to CF (control group). In the intervention group, a specific value of the lesion size index (LSI), estimating ablation lesions size was targeted for each ablation lesion. Patients underwent electrophysiological study (EPS) after 3 months to assess occurrence of the primary endpoint of re-conduction across the cavo-tricuspid isthmus (CTI). We included 156 patients with typical AFL, median age was 68 [interquartile range (IQR) 61–74] years and 120 (77%) patients were male. At index procedure median LSI was higher in the intervention group [6.4 (IQR 5.1–7) vs. 5.6 (IQR 4.5–6.9), P Conclusion Contact force-guided ablation does not reduce re-conduction across the CTI after 3 months, nor does CF-guided ablation shorten fluoroscopy, ablation, or total procedure times.

Background/Introduction The novel catheter with 6 thermocouples for real-time temperature monitoring during irrigated radiofrequency ablation was designed to potentially enhance safety and effectiveness of the Smart Touch Surround Flow (STSF) catheter by incorporating real-time temperature sensing. A supplementary, novel algorithm was developed to modulate power to maintain target temperature during high power/short duration ablation (90W, 4s). Purpose This sub-analysis was performed to examine consistency and reproducibility of the procedural efficiencies and acute success of the novel catheter with optimized temperature control and microelectrodes in treating paroxysmal atrial fibrillation (PAF) across multiple sites from two initial feasibility studies, in standard (QMODE) and high power/short duration (QMODE+) temperature-control ablation modes. Methods The QDOT-MICRO (QMODE, NCT02944968; N=42) and QDOT-FAST (QMODE+, NCT03459196; N=52) studies were both prospective, non-randomized multi-center, clinical investigations completed across 6 and 7 centers, respectively, in Europe. Procedural efficiencies and acute success (PVI via entrance block) was examined across sites within the study. Results In the QDOT-MICRO study, median procedure time (105–155 min), RF ablation time (27.7–39.5 min), and fluoroscopy times (2.2–8 min) during QMODE ablation were similar across the 6 sites. In QMODE+ ablation, median procedure time, RF ablation time, and fluoroscopy times all fall within (84–134 min), (4.8–9.7 min) and (1.1–9.6 min), respectively, across the 7 sites. Fluid delivery by the study catheter was low in both studies: QDOT-MICRO 547±278mL (mean ± SD); QDOT-FAST 382±299. mL (mean ± SD); which is 39.1 and 57.4% lower, respectively, than reported in the SMART SF trial. Esophageal temperature probe was used in the majority of patients (30/42 for QDOT MICRO and 51/52 for QDOT-FAST). Acute PVI was successful in 100% of patients in both studies with no deaths or unanticipated AEs. Conclusion(s) In both feasibility studies, procedural efficiencies were reproducible across study sites in both QMODE and QMODE+, with 100% acute success and good safety outcomes. Efficiencies are likely to improve with further experience. These results need to be confirmed in larger trials. Acknowledgement/Funding Both Studies are Company Sponsored Studies funded by Biosense Webster, Inc.

Introduction Cavo tricuspid isthmus ablation (CTIA) is an effective first-line treatment for typical atrial flutter (AFL). However, many patients develop atrial fibrillation (AF) after successful CTIA. Knowledge about recurrent arrhythmia after CTIA mainly comes from small cohort studies with limited follow-up. Purpose To describe incidences of AFL re-ablation and AF-ablation after first-time CTIA in a nation-wide cohort. Method In the Danish National Ablation Registry we identified patients undergoing first-time CTIA during 2010–2016. Subsequent CTIA and AF-ablation procedures were identified until March 1st, 2018. We gathered information on patient comorbidities in the Danish National Patient Registry. Results We identified 2409 patients undergoing first-time CTIA. Median age was 66 (IQR 58–72) years, and 1952 (81%) were men. 78 (3%) had a history of AF. Acute procedural succes was achieved in 2288 (95%) patients. During mean follow-up of 4±1.7 years, 242 (10%) patients underwent CTI re-ablation and 326 (13.5%) ablation for AF. Baseline characteristics associated with CTI re-ablation included prolonged procedural time, unsuccessful first CTIA, age Predictive characteristics Characteristics associated with CTI re-ablation HR 95% CI p-value Procedural time 1.003 (1.001–1.006) 0.01 Unsuccesful first CTIA procedure 3.42 (2.10–5.55) Conclusion In a nation-wide cohort undergoing CTIA for AFL, 10% of patients underwent CTI re-ablation and 13.5% were ablated for AF during mean follow-up of 4±1.7 years. Probability of undergoing a second ablation procedure was higher in younger patients with less comorbidity.

We present an approach for improving DNN solution by running multiple instances of the same training (where everything is the same except different seed for weight initialization). We show that significant improvements in accuracy can be achieved by using proposed approach. Additionally, we tested two simple stopping criteria that aim to identify best performing networks in the early stage of the training. This allows us to save majority of computational resources as we fully train only one network while terminating other instances of the training in an early phase. We tested combination of 20 repetitions in repeated training with global and gradual stopping rule. Repeated training with global stopping at approx. 1% of average training time can beat average performing network and stopping at approx. 10% of average training time can significantly outperform average network. Furthermore, this approach does not involve additional manual work and requires only small amount of additional computation.

This study sought to evaluate the value of combined electrogram (EGM) information provided by simultaneous mapping using micro- and conventional electrodes in the identification of post-myocardial infarction ventricular tachycardia substrate.Ventricular tachycardias after myocardial infarction are related to scars with complex geometry. Scar delineation and ventricular tachycardia substrate identification relies on bipolar voltages (BV) and EGM characteristics. Early reperfusion therapy results in small, nontransmural scars, the details of which may not be delineated using 3.5 mm tip catheters.Nine swine with early reperfusion myocardial infarction were mapped using Biosense Webster's QDOT Micro catheter, incorporating 3 microelectrodes at the tip of the standard 3.5 mm electrode. Analysis of EGM during sinus rhythm, right ventricular pacing, and short-coupled right ventricular extrastimuli was performed. The swine were sacrificed and mapping data were projected onto the heart. Transmural biopsies (n = 196) corresponding to mapping points were obtained, allowing a head-to-head comparison of EGM recorded by micro- and conventional electrodes with histology.To identify scar areas using standard electrodes, unique cutoff values of unipolar voltage 5.44 mV, BV 1.27 mV (conventional), and BV 2.84 mV (microelectrode) were identified. Combining the information provided by unipolar voltage and BV mapping, the sensitivity of scar identification was increased to 93%. Micro-EGM were better able to distinguish small near-fields corresponding to a layer of viable subendocardium than conventional EGM were.The combined information provided by multisize electrode mapping increases the sensitivity with which areas of scar are identified. EGM from microelectrodes, with narrower spacing, allow identification of near-fields arising from thin subendocardial layer and layers activated with short delay obscured in EGM from conventional mapping catheter.

OBJECTIVES: The authors conducted a multicenter study of decrement-evoked potential (DEEP)-based functional ventricular tachycardia (VT) substrate modification to evaluate if such a mechanistic and physiological strategy is feasible and efficient in clinical practice and provides reduction in the VT burden.BACKGROUND: Only a fraction of the myocardium targeted in current VT substrate modification procedures is involved in the initiation and perpetuation of VT. The physiological basis of the DEEP strategy for identification of areas of initiation and maintenance of VT was recently established.METHODS: We included 20 consecutive patients with ischemic cardiomyopathy. During substrate mapping, fractionated and late potentials (LPs) were tagged, and an extra stimulus was performed to determine which LPs displayed decrement (DEEPs). All patients underwent DEEP-focused ablation: elimination of DEEP + further radiofrequency (RF) if VT was still inducible. Patients were followed during 6 months.RESULTS: Patients were predominantly male (95%), and their mean age was 64.6 ± 17.1 years. Mean left ventricular ejection fraction was 33.4 ± 11.4%. Mean ablation time was 30.6 ± 20.4 min. Specificity of DEEPs to detect the isthmus of VT was better than that of LPs (0.97 [95% confidence interval [CI]: 0.95 to 0.98] vs. 0.82 [95% CI: 0.73 to 0.89]), without significant differences in terms of sensitivity (0.61 [95% CI: 0.52 to 0.69] vs. 0.60 [95% CI: 0.44 to 0.74], respectively). Fifteen of 20 (75%) patients were free of any VT after DEEP-RF at 6 months of follow-up and there was a strong reduction in VT burden compared to 6 months pre-ablation.CONCLUSIONS: In a multicenter prospective study, DEEP substrate mapping identified the functional substrate critical to the VT circuit with high specificity. DEEP-guided VT ablation, by its physiological nature, may enable greater access to focused ablation therapy for patients requiring VT treatment.

AIMS: To assess the long-term mortality and occurrence of post-ablation atrial fibrillation in patients undergoing a radiofrequency ablation for the Wolff-Parkinson-White (WPW) syndrome.METHODS AND RESULTS: A retrospective cohort study of patients (N = 362) subjected to radiofrequency ablation of the WPW syndrome at Aarhus University Hospital from 1990 to 2011. A comparison cohort (N = 3619) was generated from the Danish National Board of Health Central Population Registry. We found no significant difference in all-cause mortality when comparing the WPW group with the control group [hazard ratio (HR): 0.77 and confidence interval (CI): 0.47-1.25]. After radiofrequency ablation, the WPW group had a significantly higher risk of atrial fibrillation than the control group (HR: 4.77 and CI: 3.05-7.43). Atrial fibrillation prior to ablation (HR: 4.66 and CI: 2.09-10.41) and age over 50 years (HR: 9.79 and CI: 4.29-22.36) at the time of ablation were independent risk factors for post-ablation atrial fibrillation in the WPW group.CONCLUSION: Patients with radiofrequency ablation-treated WPW syndrome have a post-ablation mortality that is similar to the background population. The risk of atrial fibrillation remains high after radiofrequency ablation of the WPW syndrome.

Objectives The aim of this study was to evaluate irrigated-tip catheter for ablation of intraatrial reentrant tachycardias late after surgical repair of congenital heart disease. Background In congenital heart disease patients, the right atrium can be markedly enlarged with areas of low blood flow. Radiofrequency (RF) lesion creation may be hampered by insufficient electrode cooling at sites with low blood flow. Methods Thirty-six consecutive patients with intraatrial reentrant tachycardia refractory to antiarrhythmic therapy from two centers were included in the study. Entrainment pacing and electroanatomic mapping (CARTO®) were used to delineate reentrant circuits and critical isthmus sites. RF ablation was performed using an irrigated-tip catheter (Navistar Thermocool®). Results Fifty-two intraatrial reentrant tachycardia circuits were identified, and 48 were targeted with RF ablation. RF ablation was performed using a mean of 13 ± 11 irrigated RF applications per tachycardia isthmus with a mean power of 36 ± 8 W. In a historical control group of congenital heart disease patients managed with conventional catheter ablation, the number of lesions per isthmus was higher (23 ± 11) and mean power was lower (27 ± 14 W). Acute success was achieved in 45 intraatrial reentrant tachycardias (94% of targeted tachycardias and 87% of all tachycardias). After a mean follow-up of 17 ± 7 months, 33 (92%) of 36 patients were free of recurrence. Five patients (14%) developed paroxysmal atrial fibrillation. Conclusions The combination of modern techniques including electroanatomic mapping and catheter irrigation allows safe and highly effective ablation of intraatrial reentrant tachycardia in patients with surgically repaired congenital heart disease.

Objectives: We conducted a study to assess the procedural success and long-term freedom from arrhythmia in patients treated with radiofrequency ablation (RFA) for idiopathic ventricular arrhythmia (VA) with and without arrhythmia-induced cardiomyopathy (AIC). Design: We identified 131 patients treated with RFA for idiopathic VA in our institution; sixteen of whom had AIC. Data were obtained from patient files. A questionnaire was used to assess improvement in subjective symptoms late after RFA. Results: At the initial RFA, any VA was abolished in 93 patients (71%), non-targeted VA still was observed in 5 patients (4%), and the targeted VA remained present in 29 (22%). In 4 patients (3%) procedural success was undeterminable. During a median follow-up time of 8 months after latest RFA, 100 patients (76%) stayed free from recurrence. We observed no difference in procedural or long-term success between patients with and without AIC. When excluding patients with fascicular VT, a significantly higher proportion of patients with AIC had VA originating from the left ventricle (p=0.027). Patients with AIC had a significant improvement of EF after RFA (p

Aim Post-operative atrial tachyarrhythmias (AT) in patients with tetralogy of Fallot (ToF) are associated with congestive heart failure, stroke, and cardiac death. Effective treatment is therefore essential. The aim of the study is to evaluate long-term outcome of ablative therapy of AT in ToF patients and to study characteristics of AT recurrences. Methods and results Tetralogy of Fallot patients ( N = 38, age 43 ± 12 years) referred for ablation of post-operative AT, appearing 26 ± 10 years after complete repair, were studied. Electro-anatomical/entrainment mapping was performed prior to ablation. Successful ablation was defined as (i) achievement of bi-directional conduction block for isthmus-dependent atrial flutter (IDAF), (ii) termination during ablation for intra-atrial reentrant tachycardia (IART) and focal atrial tachycardia (FAT). Fifty-two AT were ablated, including 37 IDAF [cycle length (CL) 294 ± 70 ms], 11 IART (CL 295 ± 46 ms), and 4 FAT (CL 371 ± 93 ms). Ablation was successful in 98%. Fifty-one of 52 AT involved the cavo-tricuspid isthmus and/or the area between scar tissue related to prior atriotomy incisions and the inferior caval vein. Multiple AT developed in 11 patients, with different mechanisms in 9. After 45 ± 24 months, 32 patients were in sinus rhythm; 5 used anti-arrhythmic drugs. Conclusion Ablative therapy of AT in ToF patients is an effective curative treatment modality with a high procedural success rate. Sinus rhythm during long-term follow-up was obtained in the majority of patients. Fifty-one of 52 AT originated from sites related to surgical incisions created at complete repair, suggesting that extending the atriotomy incision towards the inferior caval vein during cardiac surgery combined with surgical ablation of the cavo-tricuspid isthmus will be effective in preventing development of AT.

Image segmentation is first and very important step in image analysis. The main idea of image segmentation is to simplify and change image into easier and meaningful form to analyze. Image segmentation is process, which locate objects in image. Many segmentation algorithms have been created for different applications. The algorithms are used in traffic applications, army applications, web applications, medical applications, studying and many others. In present time, do not exist restful objective methods to evaluate segmentation algorithms. This paper presents evaluation criterion based on measurement of precision of boundary segmentation. Moreover, the automatic segmentation algorithms in comparison with human segmentation results were tested. Four most used image segmentation algorithms, namely, Efficient graph based, K-means, Mean shift and Belief propagation are compared by designed criterion. The criterion computes three evaluation parameters like precision, recall and F1 and the results are presented in the tables and graphs at the end of the paper. K e y w o r d s: image, segmentation, algorithm, evaluation criterion

In this paper, a stereo matching algorithm based on image segments is presented. We propose the hybrid segmentation algorithm that is based on a combination of the Belief Propagation and Mean Shift algorithms with aim to refine the depth map by using a stereo pair of images. Firstly, a color based segmentation method is applied for segmenting the left image of the input stereo pair (reference image) into regions. The aim of the segmentation is to simplify representation of the image into the form that is easier to analyze and is able to locate objects in images. Secondly, results of the segmentation are used as an input of the local window-based matching method to determine the disparity estimate of each image pixel. The obtained experimental results demonstrate that the final depth map can be obtained by application of segment disparities to the original images.

In the image analysis, image segmentation is the operation that divides image into set of different segments. The paper deals about common color image segmentation techniques and methods. The advantages and disadvantage of each one will be described in this paper. At the end of the paper, the evaluation criterion will be introduced and applied on the algorithms results. Five most used image segmentation algorithms, namely, Efficient graph based, K-means, Mean shift, Expectation maximization and hybrid method are compared by designed criterion.

Background— Catheter ablation has evolved as a possible curative treatment modality for supraventricular tachycardias (SVT) in patients with univentricular heart. However, the long-term outcome of ablation procedures is unknown. We evaluated the procedural and long-term outcome of ablative therapy of late postoperative SVT in patients with univentricular heart. Methods and Results— Patients with univentricular heart (n=19, 11 male; age, 29�9 years) referred for ablation of SVT were studied. Ablation was guided by 3D electroanatomic mapping in all but 2 procedures. A total of 41 SVT were diagnosed as intra-atrial reentrant tachycardia (n=30; cycle length, 310�68 ms), typical atrial flutter (n=4; cycle length, 288�42 ms), focal atrial tachycardia (n=6; cycle length, 400�60 ms), and atrial fibrillation (n=1). Ablation was successful in 73% of intra-atrial reentrant tachycardia, 75% of atrial flutter, and all focal atrial tachycardia and focal atrial fibrillation. During the follow-up period of 53�34 months, 2 patients were lost to follow-up, 3 died of heart failure, 2 underwent heart transplantation, and 1 underwent conduit replacement. Of the remaining group, 8 had sinus rhythm and 3 had SVT. Conclusions— Focal and reentrant mechanisms underlie postoperative SVT in patients with univentricular heart. Successive SVT developing over time may be caused by different mechanisms. Ablative therapy is potentially curative, with a procedural success rate of 78%. In patients who had multiple ablation procedures, the SVT originated from different atrial sites, suggesting that these new SVT were caused by progressive atrial disease. Despite recurrent SVT, sinus rhythm at the end of the follow-up period was achieved in 72%.

BACKGROUND: Atrial flutter is a serious problem after surgery for congenital heart disease. METHODS: We performed an intraoperative linear one-minute cryolesion between a right atriotomy and the tricuspid annulus to prevent atrial flutter in 17 consecutive adult patients undergoing surgery for congenital heart disease. Coronary angiography and electrophysiology study using an electroanatomic mapping system to assess the conduction across the line and to try to induce atrial flutter were performed three months after the operation in 15 patients. RESULTS: Eleven patients had bidirectional block in the cryolesion, four patients did not, and two patients refused the electrophysiology study and coronary angiography. All patients with terminal temperature below -151 degrees C had bidirectional block, while only one patient with terminal temperature above -151 degrees C had bidirectional block. No patient with bidirectional block and all patients without bidirectional block had inducible or spontaneous atrial flutter (p = 0.0007). No lesion of the right coronary artery was detected at coronary angiography. CONCLUSIONS: The success rate was suboptimal and the intervention is potentially proarrhythmogenic in patients without block. Preventive strategies targeting atrial flutter should be validated with regard to the block rate achieved. Udgivelsesdato: 2007-May

BACKGROUND: Several studies suggest that the superior transseptal approach to mitral valve surgery leads to sinus node dysfunction. The clinical consequences are not known. METHODS: Consecutive patients undergoing surgery for mitral valve disease from November 16, 1994 through January 26, 2004 were retrospectively evaluated. The surgeons used either the superior transseptal (group A) or left atrial approach (group B). The risk of pacemaker implantation associated with the superior transseptal approach as compared with the left atrial approach was estimated using the multivariate Cox regression analysis to adjust for possible confounders. RESULTS: We included 577 patients, 150 in group A and 427 in group B. Forty-four patients had a pacemaker implanted after the surgery; 17 in group A and 27 in group B (p = 0.010). The superior transseptal approach was an independent risk factor of pacemaker implantation in multivariate analysis (hazard ratio 2.2 [1.2 to 4.1], p = 0.014). Nineteen patients had a pacemaker implanted because of sinus node dysfunction; 9 in group A and 10 in group B (p = 0.017). Group A was an independent predictor of pacemaker implantation because of sinus node dysfunction in bivariate analyses. The risk of pacemaker implantation because of atrioventricular conduction disturbances was not different between the groups (p = 0.178). CONCLUSIONS: The superior transseptal approach has a higher risk of clinically significant sinus node dysfunction than the left atrial approach. Udgivelsesdato: 2007-Jan

Atrial fibrillation is common after mitral valve surgery. We do not know the incidence of atrial tachycardia and how it depends on the surgical approach used.The subjects of the study were 213 consecutive patients who had surgery for mitral valve disease from January 1, 2001, through January 26, 2004. The surgeons used either the superior transseptal approach (69 patients, group A) or left atrial approach (144 patients, group B). An investigator, blinded for the approach used, analyzed all 12-lead electrocardiograms taken during the admission after the operation. The data were analyzed using the Cox regression analysis as time from the operation until documentation of atrial tachycardia or atrial fibrillation on a 12-lead electrocardiogram. Hazard ratio (95% confidence interval) is reported.The superior transseptal approach (2.0 [1.1 to 3.5], p = 0.023), age 60 years or more (2.3 [1.2 to 4.6], p = 0.015), and male sex (2.6 [1.3 to 5.2], p = 0.007) were independent predictors of atrial tachycardia. Age 60 years or more was the only independent predictor of atrial fibrillation (2.0 [1.2 to 3.3], p = 0.007). Although atrial tachycardia was less frequent than atrial fibrillation in group B (p0.001), atrial tachycardia was as common as atrial fibrillation in group A (p = 0.149).The superior transseptal approach has a higher risk of atrial tachycardia than the left atrial approach. Atrial tachycardia has different predictors than atrial fibrillation and constitutes a significant problem, especially after the superior transseptal approach. These results emphasize the need to distinguish between atrial tachycardia and atrial fibrillation-two entities with different pathophysiology, therapy, and also epidemiology.

Objectives The purpose of this study was to compare atrial tachycardia circuits after a range of cardiac operations. Background Knowledge of circuits occurring in a given postsurgical substrate should help to ablate these challenging tachycardias and develop potential preventive strategies. Methods We analyzed tachycardia circuits in 83 consecutive patients (60 males; median age 47 years, range 9–73) after atrial incisions undergoing ablation of atrial tachycardias. A combined strategy of electroanatomic (CARTO) and entrainment mapping was used. Fifty-two patients (63%) underwent operation for congenital and 31 (37%) for acquired heart disease. Patients were divided into subgroups based on the intervention performed in the atria: right lateral atriotomy (39 patients), left atrial (11) and superior transseptal (10) approach to the mitral valve, biatrial heart transplantation (8), Mustard (8) and Fontan (4) procedure, and other interventions (3). Results Most of the 119 tachycardias mapped were isthmus-dependent atrial flutter (66) and incisional tachycardia (30). Isthmus-dependent atrial flutter was the most frequent arrhythmia in all subgroups except for Fontan patients, in whom incisional tachycardia was most frequent. The distribution of tachycardia circuits did not differ significantly among groups. Conclusions The observed circuits did not differ among the postsurgical substrates. Isthmus-dependent atrial flutter should be the first circuit considered in patients after atrial incisions.

LUKAC, P., et al.: Determination of Repetitive Slow Pathway Conduction for Evaluation of the Efficacy of Radiofrequency Ablation in AVNRT.Aims: To determine whether the loss of repetitive slow pathway conduction identifies a successful radiofrequency ablation of atrioventricular nodal reentry tachycardia (AVNRT). Methods and results: Thirty nine consecutive patients undergoing ablation of AVNRT using the slow pathway approach were included. At baseline and after each radiofrequency application with an episode of junctional rhythm, repetitive slow pathway conduction was assessed as follows: Effective refractory period of the fast pathway was determined. The coupling interval of the first atrial extrastimulus (A2) was set at 30 ms below the effective refractory period of the fast pathway to ensure its conduction via the slow pathway. The second atrial extrastimulus (A3) was introduced at progressively longer coupling intervals starting from 200 ms until: (1) it propagated to the His bundle or (2) an anterogradely blocked AV nodal echo of A2 appeared before a conducted A3 depolarized the atrium in the His bundle electrogram. The response was termed repetitive slow pathway conduction if A3 was conducted with anAH > 200 ms. Application was considered successful if no AVNRT could be induced. Repetitive slow pathway conduction was present after 1 of 39 successful and after 34 of 40 ineffective applications(P < 0.0001). Repetitive slow pathway conduction identified a successful application with 97% sensitivity, 86% specificity, 86% positive predictive value, and 97% negative predictive value. Conclusion: The presence of repetitive slow pathway conduction identifies an unsuccessful application with a clinically meaningful negative predictive value. (PACE 2003; 26[Pt. I]:827–835)