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Kontext: Nasim cilem bylo zjistit, zda casově zavisle sniženi voltaže (dV/dt) na komorových elektrogramech (EGM) během katetrizacni ablace idiopatických arytmii z výtokoveho traktu prave komory (right ventricular outflow tract, RVOT) s použitim systemu Stereotaxis Niobe II představuje ucinný ukazatel dlouhodobe uspěsnosti výkonu. Metody: Do studie bylo zařazeno 26 po sobě nasledujicich pacientů s akutni uspěsnou ablaci RVOT pro předcasne komorove stahy (premature ventricular contractions, PVC) a/nebo komorove tachykardie (KT) s původem nejspise v RVOT. Pozdni uspěsnost byla definovana jako vymizeni komorových ektopii z RVOT po třiměsicnim sledovani bez antiarytmik (antiarrhythmic drug, AAD). Výsledky: Po třiměsicnim sledovani vymizely symptomy i arytmie u 20 (skupina 1) z 26 pacientů (77 %), přicemž k recidivě doslo u sesti pacientů (23 %) (skupina 2). Během RF ablace byl "warming up" fenomen pozorovan u 85 %, resp. 83,33 % pacientů (p = 0,46) po průměrne době (dt 2) 4,72 ± 9,42, resp. 10,75 ± 11,34 s (p = 0,045). Doba od zahajeni aplikace RF energie (t0) do významneho sniženi voltaže (> 90 %) nebo obraceni polarity EGM (t1) u obou skupin cinila 9,11 ± 5,11, resp. 32,16 ± 10,33 (p = 0,00006). Hodnota dV/dt1 byla 95,44 ± 87,6, resp. 23,5 ± 16,97 μV/s (p = 0,024). Zavěr: Casově zavisle sniženi voltaže na komorovem EGM spolu s dobou od zahajeni RF ablace do významneho sniženi voltaže (> 90 %) nebo obraceni polarity EGM a dobou od aplikace RF energie do vzniku "warming up" fenomenu představuji možne prediktory dlouhodobe uspěsnosti RF ablace idiopatických arytmii vychazejicich z RVOT. © 2021, CKS.

BACKGROUND: Cryoballoon technology (CB-A) has become a cornerstone of atrial fibrillation (AF) ablation in terms of safety and efficacy. Data regarding CB-A in octogenarians are still scarce and limited to single center experiences. The present study sought to analyze the performances of index CB-A in patients older than 80 years-old referring to 3 high-volume European centers. METHODS AND RESULTS: We retrospectively enrolled 95 patients with a median age of 81 [80, 83] years. 62 (65.3%) patients presented with paroxysmal AF and 33 (33.7%) with persistent AF. Mean procedure and fluoroscopy times were 73.8 ± 25.2 and 15.3 ± 7.5 min, respectively. At 12 months and 24 months of follow-up, the overall freedom from AF was 81.1% and 66.6%, respectively. When divided for AF type, freedom from AF was higher in patients with paroxysmal AF (p = 0.007). Cryoballoon ablation was able to significantly improve AF-related symptoms as proven by the significant decrease in EHRA score during the follow-up (p

Funding Acknowledgements Type of funding sources: None. Background Cardiac computed tomography (CCT) is an essential tool for an efficient ablation for atrial fibrillation. 3D mapping guided ablation could also deliver sufficient results in the setting of cryoballoon ablation (CBA) with additional advantages regarding total patient radiation exposure, fluoroscopy and procedural time. Purpose To compare the 3D mapping with the Achieve® catheter versus the CCT on the procedural characteristics and acute outcome during CBA. Methods Consecutive patients who underwent CBA with the second-generation cryoballoon (CB) were retrospectively enrolled from a single centre registry. Baseline and procedural characteristics of patients with pre-procedural CCT (CT-Group) were compared to those with peri-procedural 3D mapping (Ensite PrecisionTM ) with the 1st generation Achieve® catheter (3D-Group). Results A total of 696 patients were enrolled, 327 (47%) in the CT-Group and 369 (53%) in the 3D-Group. Baseline characteristics were comparable between the two groups. Similar pulmonary vein (PV) anatomical variations were identified in both groups and all PVs were acutely isolated. The mean CB temperature (T) at 60s, the nadir T, the time to PV isolation, the T of isolation and the mean thaw time did not differ significantly. However, the total procedural and fluoroscopy time were significantly shorter as well as the dose area product was significantly less in the 3D-Group. Conclusion 3D mapping guided CBA using the Achieve® catheter is associated with significantly shorter fluoroscopy and procedural time and less patient radiation exposure. The anatomical acquisition of the PVs and the acute ablation outcome is non inferior to the CCT guided CBA. Procedural characteristics CT-Group n = 327 3D- Groupn = 369 p-value Paroxysmal AF 214 244 0.87 Total procedure time (min) 73.3 ± 23.1 65.1 ± 18.9 < 0.01 Fluoroscopy time (min) 14.9 ± 7.7 12.6 ± 7 0.02 DAP (Gy·cm2) 5924 ± 4991 4890 ± 3790 0.04 LCPV 37 41 1.00 RMPV 20 21 0.87 Mean T at 60s(oC) -41.9 ± 8.5 -40.6 ± 10.7 0.10 Mean nadir T(oC) -49.5 ± 6.4 -48.4 ± 7.8 0.18 Mean PVI time(s) 42.4 ± 26.3 38.1 ± 24.3 0.11 Mean PVI temperature(oC) -33.4 ± 11.6 -31.1 ± 22 0.16 Mean thaws time(s) 51.5 ± 20.5 51.8 ± 20.3 0.85

Aims Vascular complications are the most common complications of atrial fibrillation (AF) ablation. Cryoballoon (CB) ablation for AF needs the insertion of a large 15 Fr sheath in the femoral vein. Our aim was to investigate the impact of vascular ultrasound (US) in guiding access and evaluating post-procedural subclinical complications in a large, multi-centre patient cohort that underwent CB ablation. Methods and results A total cohort of 1435 consecutive patients were subdivided in 870 US -/-, 265 US -/+, and 300 US +/+ patients depending on US performance for: venipuncture guidance/post-procedural evaluation. Major clinical complications (requiring intervention and/or prolonged stay) were assessed. Irrespective of the clinical status, major US events were systematically determined in the subgroups with US evaluation 1 day post-procedure, if evidence of inadvertent artery puncture/cannulation (communication between artery and collection or artery-vein, regardless of the thrombosis state). Major clinical events were encountered in 1.7% (15/870), 1.1% (3/265), and 0% of patients in US -/-, US -/+, and US +/+ group, respectively (P = 0.02 between US -/- and US +/+ group). In the US -/- group, 5/10 (50%) of pseudo-aneurysms were diagnosed during readmission after a mean of 24 ± 11 days post-procedure. No delayed presentation was seen in the US -/+ group. Major US events during the US protocol post-procedure were seen in 3.8% (10/265) vs. 0.3% (1/300) of patients in US -/+ vs. US +/+ group, respectively, P = 0.004. Conclusion US-guided venipuncture was associated with a near-to-zero risk of vascular complications in our patients undergoing CB ablation.

Aims To define predictors of complications of pulmonary vein isolation (PVI) and compare safety between different ablation techniques. Methods and results One thousand patients with atrial fibrillation (AF) (age 60 ± 10, 72% males, CHA2DS2-VASc score 1 ± 1) underwent PVI using various techniques: conventional PVI (CPVI) using mapping with irrigated point-per-point RF ablation (n = 576), multi-electrode RF ablation with the pulmonary vein ablation catheter (PVAC) (n = 272) or high density mesh ablator (HDMA) (n = 59) and cryoballoon (CB) ablation (n = 93). A complication was defined as any procedure-related adverse event resulting in permanent injury or death, requiring intervention or treatment, or prolonging/requiring hospitalization for >48 h. A total of 105 (10.5%) complications occurred in 101 (10.1%) patients. No periprocedural death occurred. Most frequent complications were vascular complications (4%) and pericarditis (3.1%). Seven patients experienced permanent deficit due to PV stenosis (n = 3, 1 CPVI, 2 PVAC) (n = 3) and phrenic nerve palsy (PNP) (n = 4, 3 CPVI, 1 PVAC). Independent predictors of complications were female sex [odds ratio (OR) = 1.73; 95% confidence interval (CI) 1.08-2.79; P = 0.023], CHA2DS2-VASc score (OR = 1.24; 95% CI 1.01-1.52; P = 0.039), and ablation technique (P = 0.006) in multivariable-adjusted analysis. Among the different techniques, CB (P = 0.047) and PVAC ablation (P = 0.003) had lowest overall complication rates. Complication profile (type/severity) differed between techniques (association between CB and PNP, CPVI and pericardial injury, PVAC and transient ischaemic attack/PV stenosis). Conclusion Overall complication rate of PVI with various techniques is 10.5%. Permanent deficit occurred only after PVAC and CPVI in 0.7% of patients. Female sex and a higher CHA2DS2-VASc score increase, while PVAC and CB-PVI decrease, overall risk. Differences in overall safety and individual complication profile make selection of the ablation technique in relation to clinical risk profile possible.

Patients with ischemic cardiomyopathy (ICM) are prone to scar-related ventricular tachycardia (VT). The success of VT ablation depends on accurate arrhythmogenic substrate localization, followed by optimal delivery of energy provided by constant electrode-tissue contact. Current manual and remote magnetic navigation (RMN)-guided ablation strategies aim to identify a reentry circuit and to target a critical isthmus through activation and entrainment mapping during ongoing tachycardia. The MAGNETIC VT trial will assess if VT ablation using the Niobe™ ES magnetic navigation system results in superior outcomes compared to a manual approach in subjects with ischemic scar VT and low ejection fraction. This is a randomized, single-blind, prospective, multicenter post-market study. A total of 386 subjects (193 per group) will be enrolled and randomized 1:1 between treatment with the Niobe ES system and treatment via a manual procedure at up to 20 sites. The study population will consist of patients with ischemic cardiomyopathy with left ventricular ejection fraction (LVEF) of ≤35% and implantable cardioverter defibrillator (ICD) who have sustained monomorphic VT. The primary study endpoint is freedom from any recurrence of VT through 12 months. The secondary endpoints are acute success; freedom from any VT at 1 year in a large-scar subpopulation; procedure-related major adverse events; and mortality rate through 12-month follow-up. Follow-up will consist of visits at 3, 6, 9, and 12 months, all of which will include ICD interrogation. The MAGNETIC VT trial will help determine whether substrate-based ablation of VT with RMN has clinical advantages over manual catheter manipulation. Clinicaltrials.gov identifier: NCT02637947

BACKGROUND: In the setting of second-generation cryoballoon (CB2) ablation, left atrial (LA) access is generally achieved using a standard sheath (SS) that is exchanged for the 15Fr cryoballoon delivery sheath (CBS) and dilator over a long wire (CBS over-the-wire technique, CBS-W). Our objective was to evaluate the direct use of the CBS to gain LA access, by advancing the latter over the trans-septal needle (CBS over-the-needle technique, CBS-N), under transesophageal echocardiographic (TEE) guidance. METHODS: Consecutive patients who underwent CB2 ablation with the CBS-N technique were evaluated for feasibility of gaining LA access using TEE guidance and fluoroscopy views. Complications related to the LA access were compared with a matched CBS-W control group. Subanalysis (30 CBS-W vs 30 CBS-N patients) evaluated time-to-LA of the CBS: time from superior vena cava (with SS vs CBS) to LA insertion of the CBS, after exchange or directly, respectively. RESULTS: LA access could be achieved in all 505 patients of the CBS-N group, without technique modification or additional equipment. Challenging interatrial septa were noted in 13% of these patients: previous atrial septal defect repair (1%), hypermobile (10%), aneurysmal (1%), and abnormally thickened/fibrotic (1%). Incidence of complications was similar to the CBS-W group. Subanalysis showed a shorter time-to-LA in the CBS-N versus CBS-W group, 72 ± 46 seconds versus 293 ± 180 seconds, P < .001. CONCLUSIONS: Our study showed that the CBS-N technique is feasible and safe under echocardiographic guidance. Without sheath exchange, it simplifies the CB2 procedure, is less costly, time sparing, and might reduce the risk of air embolism.

Remote Navigation of Circular Mapping Catheters Introduction Circular mapping catheters (CMC) are an essential tool in most atrial fibrillation ablation procedures. The Vdrive™ with V-Loop™ system enables a physician to remotely manipulate a CMC during electrophysiology studies. Our aim was to compare the clinical performance of the system to conventional CMC navigation according to efficiency and safety endpoints. Methods and Results A total of 120 patients scheduled to undergo a CMC study followed by pulmonary vein isolation (PVI) were included. Treatment allocation was randomized 2:1, remote navigation:manual navigation. The primary effectiveness endpoint was assessed based on both successful navigation to the targeted pulmonary vein (PV) and successful recording of PV electrograms. All PVs were treated independently within and between patients. The primary safety endpoint was assessed based on the occurrence of major adverse events (MAEs) through seven days after the study procedure. Primary effectiveness endpoints were achieved in 295/302 PVs in the Vdrive arm (97.7%) and 167/167 PVs in the manual arm (100%). Effectiveness analysis indicates Vdrive non-inferiority (pnon-inferiority = 0.0405; δ = –0.05) per the Cochran–Mantel–Haenszel test adjusted for PV correlation. Five MAEs related to the ablation procedure occurred (three in the Vdrive arm—3.9%; two in the manual arm—2.33%). No device-related MAEs were observed; safety analysis indicates Vdrive non-inferiority (pnon-inferiority = 0.0441; δ = 0.07) per the normal Z test. Conclusion Remote navigation of a CMC is equivalent to manual in PVI in terms of safety and effectiveness. This allows for single-operator procedures in conjunction with a magnetically guided ablation catheter.

Aims: To define predictors of complications of pulmonary vein isolation (PVI) and compare safety between different ablation techniques. Methods and results: One thousand patients with atrial fibrillation (AF) (age 60 ± 10, 72% males, CHA2DS2-VASc score 1 ± 1) underwent PVI using various techniques: conventional PVI (CPVI) using mapping with irrigated point-per-point RF ablation (n = 576), multi-electrode RF ablation with the pulmonary vein ablation catheter (PVAC) (n = 272) or high density mesh ablator (HDMA) (n = 59) and cryoballoon (CB) ablation (n = 93). A complication was defined as any procedure-related adverse event resulting in permanent injury or death, requiring intervention or treatment, or prolonging/requiring hospitalization for >48 h. A total of 105 (10.5%) complications occurred in 101 (10.1%) patients. No periprocedural death occurred. Most frequent complications were vascular complications (4%) and pericarditis (3.1%). Seven patients experienced permanent deficit due to PV stenosis (n = 3, 1 CPVI, 2 PVAC) (n = 3) and phrenic nerve palsy (PNP) (n = 4, 3 CPVI, 1 PVAC). Independent predictors of complications were female sex [odds ratio (OR) = 1.73; 95% confidence interval (CI) 1.08-2.79; P = 0.023], CHA2DS2-VASc score (OR = 1.24; 95% CI 1.01-1.52; P = 0.039), and ablation technique (P = 0.006) in multivariable-adjusted analysis. Among the different techniques, CB (P = 0.047) and PVAC ablation (P = 0.003) had lowest overall complication rates. Complication profile (type/severity) differed between techniques (association between CB and PNP, CPVI and pericardial injury, PVAC and transient ischaemic attack/PV stenosis). Conclusion: Overall complication rate of PVI with various techniques is 10.5%. Permanent deficit occurred only after PVAC and CPVI in 0.7% of patients. Female sex and a higher CHA2DS2-VASc score increase, while PVAC and CB-PVI decrease, overall risk. Differences in overall safety and individual complication profile make selection of the ablation technique in relation to clinical risk profile possible.

Background Second generation cryoballoon (CB-A) ablation is highly effective in achieving pulmonary vein (PV) isolation and freedom from atrial fibrillation (AF). However, the ideal freezing strategy is still under debate. Our objective was to investigate the efficacy and outcome between different freezing strategies used with the CB-A in a multicenter, matched population. Methods From a total cohort of 1018 patients having undergone CB-A ablation for drug-refractory AF, 673 patients with follow-up ≥ 6 months were included and stratified according to the applied freezing strategy: bonus freeze (BF) versus single freeze (SF). Final population of 256 BF patients was compared with 256 propensity-score matched SF patients. Results BF strategy consisted of 3 different protocols: 3 cycles of 180 s; 2 cycles of 240 s; and cycles of 240 s followed by 180 s in 99/256 (39%); 42/256 (16%); and 115/256 (45%) patients, respectively. SF approach included cycles of 240 s in 23/256 (9%), and 180 s in 233/256 (91%) patients. Electrical isolation could be achieved in all PVs by both protocols, with shorter procedure and fluoroscopy times in the SF group (mean 106 vs 65 min, and 18 vs 14 min, respectively, P < 0.001). Phrenic nerve palsy persisted after discharge in a total of 11 patients (2.1%): 4 (1.6%) in the BF group vs 7 (2.7%) in the SF group, P = 0.5. AF-free survival was similar between the 2 groups during follow-up (mean 18 ± 10 months) (log rank, P = 0.6). Conclusions CB-A ablation showed equal efficacy and outcome between SF and BF strategy.

Aims Atrial tachycardias (ATs) frequently develop in patients with congenital heart defects (CHDs). This study aimed to evaluate the effects of extensive atrial scar formation on the total atrial activation time (TAAT) and its relation to the tachycardia cycle length (CL) to classify AT. Methods and results Seventy-one patients were included and divided into two groups: patients without CHD (Group I, 35 patients) and with CHD (Group II, 36 patients). All patients underwent CARTO electroanatomical activation mapping. Two subgroups were created: centrifugal (CAT) or macroreentrant AT (MRAT). Total atrial activation time, CL, and mean bipolar signal amplitude (BiSA) were analysed. In Group I, 18 patients (51.4%) had CAT and 17 (48.6%) MRAT. The mean BiSA for Group I was 1.30 ± 0.32 mV. Total atrial activation time/CL ratios were different between CAT and MRAT (28.4 ± 16.9 vs. 66.6 ± 14.3%, P < 0.001). In Group II, 18 patients (50%) had CAT and 18 patients (50%) MRAT. The mean BiSA was 0.94 ± 0.50 mV and was not different for CAT and MRAT subgroups (1.04 ± 0.64 vs. 0.85 ± 0.29, P = 0.243). Total atrial activation time/CL ratios were comparable between CAT and MRAT patients (69.0 ± 40.4 vs. 83.6 ± 8.3%, P = 0.243). A significant lower BiSA was found for CAT with TAAT/CL ratios above 40% (0.62 ± 0.11 vs. 1.90 ± 0.18 mV, P < 0.001). A strong negative correlation was identified between the BiSA and the TAAT/CL ratio in patients with CAT in Group II (−0.742; P < 0.001). Conclusion Low mean BiSA values in CHD patients are associated with altered impulse propagation, making TAAT- and CL-based diagnostic tools inaccurate. Further diagnostic tests are needed to determine the correct mechanism of ATs.

Aims The aim of the study is to define long-term outcome of pulmonary vein isolation (PVI) in atrial fibrillation (AF) and to determine whether time window between AF diagnosis and PVI affects outcome. Methods and results Consecutive AF patients undergoing PVI (2006-14) were followed for 5 years. Primary outcome was clinical success, defined as freedom of documented AF without anti-arrhythmic drugs respecting a 1-month blanking period. A 1000 patients were included (age 60 ± 10 years, CHA 2 DS 2 -VASc score 1 ± 1). The cohort was divided in four quartiles (Q) according to the diagnosis-to-ablation time (DAT): Q1 DAT 0-11 months (N = 244), Q2 DAT 12-≤33 months (N = 254), Q3 DAT 34-≤70 months (N = 252) and Q4 DAT 71-360 months (N = 250). Mean follow-up was 44.3±21.0 months. At 5 years, clinical success was achieved in 45.2 ± 2.0% of patients. Independent predictors of clinical success were AF type (HR = 0.61; 95%CI 0.50-0.74; P < 0.0001), left atrial size (HR = 1.03; 95%CI 1.02-1.05; P < 0.0001), DAT (HR = 1.00; 95%CI 1.00-1.00; P = 0.001), ablation technique (P = 0.012), and year of ablation (HR = 0.93; 95%CI 0.86-1.00; P = 0.045) in multivariable-adjusted analysis. The highest clinical success was achieved when PVI was performed within the first year, and gradually declined with increasing DAT: 55.9 ± 4.6% for Q1, 46.9 ± 4.0% for Q2, 45.5 ± 3.6% for Q3, and 35.5 ± 3.6% for Q4 (P < 0.001). Conclusion Long-term success rate of PVI is 45.2 ± 2.0%. Shorter diagnosis-to-ablation times are associated with better clinical success. Our data advocate for early PVI following diagnosis of AF.

Objective Atrial fibrillation (AF) is a common arrhythmia in clinical practice. AF fulfils many of the criteria for a screening programme. No data about the prevalence of AF in non-hospitalized patients are available in Belgium. The aim of the study was to assess feasibility and effectiveness of a nationwide-organized voluntary screening programme in the general population in Belgium. Methods A total of 13.564 participants were screened, of whom 10,758 were older than 40 years (GSP group). Participants filled in stroke risk stratification questionnaires (CHADS2 and CHA2DS2-VASc). A one-lead electrocardiogram was performed. Results 228 participants had AF at the time of screening (AF group), with 125 women and 103 men (i.e. 1.9% and 2.6% of total women and men), representing a prevalence of 2.2% (95% Cl 1.3% and 3.0%) of the screened population. Age of the AF group was 67 +/- 12 y (range 40-87 y). Using the CHADS2-score, 58% of participants with a positive AF screening had a high risk score, and 21% had an intermediate risk score. Using the CHA2DS2-VASc-score, 72% of the participants had a high risk score, and 21% had an intermediate risk score. Conclusion AF was present in 2.2% of the respondents. At least 60% of AF group had an increased risk for thrombo-embolism. Although substantial methodological issues limit the exact interpretation of these results, the present study shows that a volunatry screening programme with a simple screening protocol is able to detect an important number of patients with previously undetected AF.

Remote Magnetic Navigation for VT Ablation. Background: This study aimed to compare acute and late outcomes of VT ablation using the magnetic navigation system (MNS) to manual techniques (MAN) in patients with (SHD) and without (NSHD) structural heart disease. Methods: Ablation data of 113 consecutive patients (43 SHD, 70 NSHD) with ventricular tachycardia treated with catheter ablation at our center were analyzed. Success rate, complications, procedure, fluoroscopy, and ablation times, and recurrence rates were systematically recorded for all patients. Results: A total of 72 patients were included in the MNS group and 41 patients were included in the MAN group. Patient age, gender, and right ventricular and left ventricular VT were equally distributed. Acute success was achieved in 59 patients in the MNS group (82%) versus 27 (66%) patients in the MAN group (P = 0.046). Overall procedural time (177 +/- 79 vs 232 +/- 99 minutes, P < 0.01) and mean patient fluoroscopy time (27 +/- 19 vs 56 +/- 32 minutes, P < 0.001) were all significantly lower using MNS. In NSHD pts, higher acute success was achieved with MNS (83,7% vs 61.9%, P = 0.049), with shorter procedure times (151 +/- 57 vs 210 +/- 96, P = 0.011), whereas in SHD-VT these were not significantly different. No major complications occurred in the MNS group (0%) versus 1 cardiac tamponade and 1 significantly damaged ICD lead in the MAN group (4.9%, NS). After follow-up (20 +/- 11 vs 20 +/- 10 months, NS), VT recurred in 14 pts (23.7%) in the MNS group versus 12 pts (44.4%) in the MAN group (P = 0.047). Conclusions: The use of MNS offers advantages for ablation of NSHD-VT, while it offers similar efficacy for SHD-VT. ((J Cardiovasc Electrophysiol, Vol. 23, pp. 948-954, September 2012)

Pulmonary vein isolation (PVI) has established itself as a standard therapy for paroxysmal atrial fibrillation (AF). Still, the most widely performed procedure of point-by-point distal-tip ablation using a 3-dimensional mapping system and a circular catheter to validate PVI remains a complex, elaborative, and time-consuming procedure. This explains the many efforts being made over the recent years to simplify and shorten PVI procedures without compromising the efficacy or the safety. The cryoballoon (Ablation Frontiers, Medtronic, Inc., Minneapolis, MN, USA) is a recently introduced “single shot ablation tool” to facilitate PVI. Initial studies on efficacy and safety of this device are encouraging in patients with paroxysmal AF. However, several controversies remain, such as the need for an additional circular mapping catheter to validate PVI and the lack of on-line PV recording during freezes. One of the most recent developments in this field is the Achieve circular mapping catheter (Ablation Frontiers, Medtronic, Inc.). We describe an apparent case in which this tool is used in conjunction with the cryoballoon. (PACE 2012; 35:e337–e340)

Introduction Remote magnetic navigated ablation has proven its feasibility in a large group of arrhythmias. Until now only scarce data are available on the use for atrial flutter. In this study we compared remote magnetic navigation (RMN), using non-irrigated and irrigated tip catheters, to manual radiofrequency ablation for ablating typical atrial flutter. Methods The 3 study groups consisted of 17 patients treated with RMN 8-mm tip; 14 patients with RMN irrigated tip; and 24 patients with a manual 8-mm tip. The primary outcome was the number of patients in whom bidirectional isthmus block could be obtained with 15 applications. Secondary end points were the median number of applications needed, the need to switch to a manual irrigated tip catheter, the procedural and fluoroscopy times. Results There was no significant difference in the primary end point (RMN 8 mm-tip group: 59%, RMN irrigated tip group: 64% and manual group: 83%). The median number of applications needed to obtain block was higher in the RMN groups compared to the manual group. In 5 patients from the RMN 8-mm tip group, 1 in the RMN irrigated tip group and 1 in the manual group, a switch to a manually irrigated tip catheter was performed. There was no difference in fluoroscopy time, but procedural time was significantly longer in the RMN groups compared to the manual group (P = 0.03). Conclusions The use of magnetic navigation for the ablation of atrial flutter is feasible but not superior to a manual approach. There was no difference concerning the primary end point of acute success within 15 applications. Overall, more applications were needed and procedure times were longer with RMN but RMN with the irrigating tip is promising.

Aims We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities. Methods and results In this study, 610 consecutive patients underwent ablation. Patients were divided into two age-and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15 +/- 9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P = 0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P = 0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P = ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P < 0.05). Less fluoroscopy was used in group MNS (30 +/- 20 vs. 35 +/- 25 min, P < 0.01). There were no differences in procedure times and recurrence rates for the overall groups (168 +/- 67 vs. 159 +/- 75 min, P = ns; 14 vs. 11%, P = ns; respectively). Conclusions Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs.

Background Radiofrequency (RF) catheter ablation for atrioventricular nodal reentrant tachycardia (AVNRT) is highly successful but carries a risk for inadvertent atrioventricular block. Cryoablation (cryo) has the potential to assess the safety of a site before the energy is applied. Purpose The aim of this study was to evaluate the long-term efficacy and safety of cryothermal ablation in a large series of patients and compare it to RF. Methods All consecutive routinely performed AVNRT ablations from our centre between 1999 and 2007 were retrospectively analysed. Results In total, 274 patients were elegible: 150 cryoablations and 124 RF. Overall procedural success was 96% (262/274), and equal in both groups, but nine patients were crossed to another arm. Mean fluoroscopy time was longer in the group treated with RF (27 ± 22 min vs. cryo 19 ± 15 min; p = 0.002). Mean procedure time was not different (RF 138 ± 71 min vs. cryo 146 ± 60 min). A permanent pacemaker was necessary in two RF patients. The questionnaire revealed a high incidence of late arrhythmia related symptoms (48%), similar in both groups, with improved perceived quality of life. The number of redo procedures for AVNRT over 4.3 ± 2.5-years follow-up was not statistically different (11% after cryo and 5% after RF). Conclusions Our data confirm that cryo and RF ablation with 4-mm tip catheters for AVNRT are equally effective, even after long-term follow-up.

Objectives: Radiofrequency catheter ablation of left-sided accessory pathways (APs) can be performed either by a transseptal (TS) or transaortic (TA) approach. When performed manually, these techniques are equally effective. The aim of this prospective randomized study was to compare these approaches using a magnetic navigation system (MNS) (Niobe, Stereotaxis, St. Louis, MO, USA). Methods: Twenty-two consecutive patients were randomized to undergo ablation of a left-sided AP by either a TS or a TA approach. The MNS was used in all patients for catheter navigation and eventual ablation, after electrophysiology study (EPS) confirmed the presence of left-sided APs. Crossover was allowed after failure of the initial approach. Success rates, procedure, fluoroscopy, and ablation times were compared. Results: Of 11 procedures, 10 (91%) were successful in the TS group. The patient crossed over to the TA approach remained unsuccessful. Successful elimination of the AP was obtained in nine (82%) of 11 of the TA procedures. Of the two patients who crossed over to a TS procedure in the same session, one was successful and one remained unsuccessful. Total procedure time did not differ in both groups (87.1 ± 30.8 vs 90.9 ± 26.5 minutes). When total procedure and patient fluoroscopy times were divided into EPS time, time to first application, to successful application, and time to perform TS puncture or to retrogradely cross the aortic valve, only the last measurement differed significantly for both groups (P < 0.01). Ablation times were comparable in both groups. No major complications occurred. Conclusions: Our data show that TS and TA approaches are equal in success rate and total procedure, patient fluoroscopy, and ablation time when using the MNS for left-sided AP ablation. However, crossing the aortic valve with the MNS is faster than completing a TS puncture. (PACE 2010; 1298–1303)

Transcatheter ablation is an effective method to eliminate the arrhythmogenic substrate in symptomatic children with various types of arrhythmias. A reduction in the procedure and fluoroscopy time would decrease the hazardous effects of the ablation procedures. The magnetic navigation system (MNS) uses atraumatic catheters and facilitates accurate catheter placement in all regions of the heart for mapping and therapy delivery. We compared the efficacy and safety between a manual and MNS-guided approach for mapping and ablation of arrhythmias in a general pediatric arrhythmia population and in a subgroup of young children aged

An 18-year-old female patient with tricuspid atresia, discordant ventriculo-arterial connections, a total cavo-pulmonary connection, and a Damus-Kaye-Stansel suffered with atrial tachycardia. Use of a magnetically navigated catheter made it possible to create an electro-anatomical map of both atriums using a retrograde approach. It then proved possible to ablate successfully the tachycardia in the left atrium thanks to the unique capabilities of the magnetic navigation system.

A baffle puncture is a challenging procedure but can be safely done using direct visualization of the region of interest. To our knowledge, however, it has never been performed in a patient with dextrocardia. We present a 62-year-old male with dextrocardia, right isomerism, congenitally corrected transposition of the great arteries, persistent left-sided superior and inferior caval veins, atrial septum defect, and pulmonary valve stenosis. The atrial septum defect was surgically closed with a Teflon((R)) patch, a variant Mustard operation was performed, and also a prosthetic tricuspid valve was implanted. The patient developed multiple episodes of atrial tachycardia leading to acute heart failure on many occasions. An electrophysiological study was undertaken in order to create a bi-atrial electro-anatomical map. Owing to the presence of a prosthetic tricuspid valve, the femoral venous access was used and a baffle puncture was performed using continuous monitoring with fluoroscopy and transoesophageal echocardiography (TEE). The baffle puncture was successful and the tachycardia was ablated in the systemic venous atrium. To our knowledge, we present the very first case report demonstrating a successful baffle puncture in a patient with dextrocardia and Mustard correction. Direct imaging using TEE seems to be a very useful tool for guiding the puncture.

Background: The improved outcomes and increased availability of surgery for congenital heart disease (CHD) over the last three decades have created a small but steadily increasing subset of patients with unique needs: children and adults with complex arrhythmias in the setting of structural cardiac abnormalities. Radiofrequency catheter ablation (RFCA) in these patients, and in small children with normal cardiac anatomy, is effective but challenging. An understanding of specific anatomical and electrophysiological characteristics of these patients and the technical challenges in addressing them are critical to the success of this therapy. Tools specifically designed for intracardiac diagnosis and therapy in anatomically complex and/or small hearts remain scarce. Aims: We report single-center results from an ongoing registry of all patients with congenital heart disease and all children with complex arrhythmias in which the Magnetic Navigation System (MNS) was used. Results: Included in this report are 12 patients with CHD in whom 17 tachyarrhythmias were treated, and 11 pediatric patients with normal cardiac anatomy who each had a single arrhythmia. The procedures' duration and the duration of fluoroscopy time as well as arrhythmia recurrence rates were comparable to those found in previous reports of procedures performed in adults with structurally normal hearts, and the incidence of complications was quite low. Discussion: In patients with complex congenital malformations, retrograde mapping of the pulmonary venous atrium was feasible, eliminating the need for puncture of the atrial septum, or surgically placed baffle in many cases. Moreover, the design of the catheter eliminated the need for multiple mapping and ablation catheters. Conclusion: Our findings suggest that RFCA using the MNS for arrhythmias after surgery for congenital heart disease and in pediatric patients is safe and effective.

To identify cTnI rise after percutaneous ISD closure and to determine its prognostic significance.Cardiac troponin-I (cTnI) is a very specific and sensitive marker of myocardial injury. A significant increase of cTnI levels after percutaneous interatrial septal defect (ISD) closure has been reported.Patients admitted for transcatheter atrial septal defect (ASD) and patent foramen ovale (PFO) closure, were enrolled in this prospective study. Standard protocol was unchanged, except for blood sampling, to which serial cTnI before, 6, and 24 hours after the procedure was added.Seventy-eight patients (female/male 37/41, mean age 55 +/- 13 y, 14 ASD and 64 PFO) were included. In none of the patients cTnI was elevated before the procedure and in no patients a cTnI rise above the WHO-criteria for myocardial infarction (= 0.4 ng/ml) was seen. However, in 32 patients (41%) minimal cTnI rise (range from 0.04 ng/ml to 0.37 ng/ml) was present within a time frame of 24 hours. The increase in cTnI was not related to peri-procedural complications and to short-term outcome (mean follow-up time of 7 +/- 5 months). In addition, cTnI rise was significantly related with the presence of hyperlipideamia (P = 0.004), device size (P = 0.008), and the absence of balloon sizing (P = 0.017).Transcatheter closure of ISD seems to be a safe procedure. A minimal but significant increase of cTnI is noted in some patients after the procedure, but it seems not to be related to short-term prognosis. However, cTnI rise is clearly associated with patients' characteristics and peri-procedural variables.

Circular mapping catheters (CMC) are an essential tool in most atrial fibrillation ablation procedures. The Vdrive™ with V-Loop™ system enables a physician to remotely manipulate a CMC during electrophysiology studies. Our aim was to compare the clinical performance of the system to conventional CMC navigation according to efficiency and safety endpoints.A total of 120 patients scheduled to undergo a CMC study followed by pulmonary vein isolation (PVI) were included. Treatment allocation was randomized 2:1, remote navigation:manual navigation. The primary effectiveness endpoint was assessed based on both successful navigation to the targeted pulmonary vein (PV) and successful recording of PV electrograms. All PVs were treated independently within and between patients. The primary safety endpoint was assessed based on the occurrence of major adverse events (MAEs) through seven days after the study procedure. Primary effectiveness endpoints were achieved in 295/302 PVs in the Vdrive arm (97.7%) and 167/167 PVs in the manual arm (100%). Effectiveness analysis indicates Vdrive non-inferiority (pnon-inferiority = 0.0405; δ = -0.05) per the Cochran-Mantel-Haenszel test adjusted for PV correlation. Five MAEs related to the ablation procedure occurred (three in the Vdrive arm-3.9%; two in the manual arm-2.33%). No device-related MAEs were observed; safety analysis indicates Vdrive non-inferiority (pnon-inferiority = 0.0441; δ = 0.07) per the normal Z test.Remote navigation of a CMC is equivalent to manual in PVI in terms of safety and effectiveness. This allows for single-operator procedures in conjunction with a magnetically guided ablation catheter.

Catheter ablation is nowadays the first therapeutic option for AVNRT, the most common benign supraventricular tachycardia. Both cryotherapy and radiofrequency energy may be used to ablate the slow pathway. This paper compares both techniques, evaluates results published in literature and gives feedback on some typical aspects of cryo- and RF ablation. Although both techniques have satisfying success rates in AVNRT ablation, with a higher safety profile of cryoablation towards creation of inadvertent atrioventricular block, it remains paramount that the operator respects the distinctive traits of each technique in order to obtain an optimal result in every patient.

Transseptal puncture is the most commonly used technique to perform electrophysiological procedures in the left atrium. This case report describes a pulmonary vein isolation in a patient with a paroxysmal atrial fibrillation, complicated by the presence of an oversized Amplatzer device (AGA Medical Corp., Golden Valley, MN). A retrograde approach using the magnetic navigation system (Niobe, Stereotaxis Inc., St Louis, USA) was performed, and showed to provide a feasible, safe and successful alternative for catheter ablation of cardiac arrhythmias in patients in whom the classic transseptal approach is impossible.

Aims Pulmonary vein isolation (PVI) is an accepted treatment to relieve symptoms in patients with atrial fibrillation (AF). We studied 3 year outcome after PVI guided by duty-cycled multi-electrode radiofrequency (RF) ablation (pulmonary vein ablation catheter, PVAC) and provided comparative data to outcome after conventional PVI (CPVI) using mapping with irrigated, point-per-point RF ablation. Methods and results One hundred and sixty-one consecutive patients with symptomatic paroxysmal or persistent AF and minimal heart disease underwent PVI (PVAC, n = 79 vs. CPVI, n = 82). Follow-up (with symptom-guided rhythm monitoring) was truncated at 3 years in all patients. Success was defined as freedom of documented arrhythmia after a single procedure and without antiarrhythmic drug treatment (ADT). Baseline characteristics did not differ between both groups. At 3 years follow-up, single-procedure success without ADT was comparable between PVAC and CPVI (65% vs. 55%, P = NS). The majority of recurrences occurred during the first year (PVAC 79% vs. CPVI 70%, P = NS). The annual rate of very late recurrence (i.e. beyond 1 year) was similar in both groups (10.5% vs. 15%, P = NS). Conclusion At 3 years follow-up, outcome after PVAC-guided PVI is comparable to conventional isolation by irrigated point-by-point RF ablation. In both strategies, the majority of recurrences occurred in the first year of ablation.

Ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) is a highly effective procedure both with radiofrequency (RF) and cryoenergy (CE). Conventionally, it requires several diagnostic catheters and hospital admission. This study assessed the safety and efficacy of a highly simplified approach using the magnetic navigation system (MNS) compared to CE and manual RF ablation (MAN).In the MNS group a single magnetic-guided quadripolar catheter was inserted through the internal jugular vein to perform ablation. In the CE group cryomapping preceded ablation and for MAN procedures conventional ablation was performed. The following parameters were analysed: success- and recurrence rate, procedure-, fluoroscopy- and total application time. In total 69 eligible patients were treated with MNS (n = 26), CE (n = 25) and MAN (n = 16). The success rates were 100%, 100% and 94%, respectively (p = ns). The mean procedural time was 83 +/- 25 min for MNS, 117 +/- 47 min for CE and 117 +/- 55 min for MAN (P0.01). Total radiation time was significantly lower for MNS [0.0 min (IQR 0.0-0.0)] compared to CE [15.1 min (IQR 9.1-23.8), P0.001] and MAN [17.5 min (IQR 7.0-31.3), P0.001]. The total application time was comparable for both RF groups: 357 +/- 315 s (MNS) vs 204 +/- 177 s (MAN) (P = 0.14). No major adverse events occurred. After 3 months follow-up similar PR intervals were recorded for all patients. During a follow-up of 26 +/- 5 months recurrence rates were 3.8%, 4.0% and 6.3%, respectively, for each group.The MNS-guided single-catheter approach is a feasible and safe technique for the treatment of patients with typical AVNRT.

We present a case report of a 78-year-old male patient, with a left arteriovenous haemodialysis fistula and left subclavian vein thrombosis treated with 2 Cordis SMART stents. Stents were implanted 2 years ago in the left subclavian vein and left innominate vein …

Background— The risk of pulmonary vein narrowing (PVN) after pulmonary vein isolation, using a novel multi-electrode ablation catheter, is unknown. Methods and Results— Left atrial volume and PV diameters were compared by computed tomography (CT) before and 3 months after pulmonary vein isolation using duty-cycled phased radio frequency energy (2:1 or 4:1 bipolar/unipolar ratio) in 50 patients. Pulmonary vein diameter was measured in a coronal and axial view at 3 levels (A, ostium; B, 1 cm more distal; C, 2 cm more distal). Moderate PVN was defined as a pulmonary vein diameter reduction of 25 to 50%, and severe PVN as >50%. Left atrial volume decreased by 12±12% ( P P P Conclusions— Isolation of the pulmonary veins using a multielectrode ablation catheter and duty cycled phased radiofrequency energy delivery results in a consistent moderate reduction of the PV diameters predominantly at the ostium. Severe PVN in 15% of patients raises concerns about the risk for clinical PV stenosis.

Pulmonary vein isolation (PVI) has established itself as a standard therapy for paroxysmal atrial fibrillation (AF). Still, the most widely performed procedure of point-by-point distal-tip ablation using a 3-dimensional mapping system and a circular catheter to validate PVI remains a complex, elaborative, and time-consuming procedure. This explains the many efforts being made over the recent years to simplify and shorten PVI procedures without compromising the efficacy or the safety. The cryoballoon (Ablation Frontiers, Medtronic, Inc., Minneapolis, MN, USA) is a recently introduced "single shot ablation tool" to facilitate PVI. Initial studies on efficacy and safety of this device are encouraging in patients with paroxysmal AF. However, several controversies remain, such as the need for an additional circular mapping catheter to validate PVI and the lack of on-line PV recording during freezes. One of the most recent developments in this field is the Achieve circular mapping catheter (Ablation Frontiers, Medtronic, Inc.). We describe an apparent case in which this tool is used in conjunction with the cryoballoon.

Radiofrequency catheter ablation of left-sided accessory pathways (APs) can be performed either by a transseptal (TS) or transaortic (TA) approach. When performed manually, these techniques are equally effective. The aim of this prospective randomized study was to compare these approaches using a magnetic navigation system (MNS) (Niobe, Stereotaxis, St. Louis, MO, USA).Twenty-two consecutive patients were randomized to undergo ablation of a left-sided AP by either a TS or a TA approach. The MNS was used in all patients for catheter navigation and eventual ablation, after electrophysiology study (EPS) confirmed the presence of left-sided APs. Crossover was allowed after failure of the initial approach. Success rates, procedure, fluoroscopy, and ablation times were compared.Of 11 procedures, 10 (91%) were successful in the TS group. The patient crossed over to the TA approach remained unsuccessful. Successful elimination of the AP was obtained in nine (82%) of 11 of the TA procedures. Of the two patients who crossed over to a TS procedure in the same session, one was successful and one remained unsuccessful. Total procedure time did not differ in both groups (87.1 ± 30.8 vs 90.9 ± 26.5 minutes). When total procedure and patient fluoroscopy times were divided into EPS time, time to first application, to successful application, and time to perform TS puncture or to retrogradely cross the aortic valve, only the last measurement differed significantly for both groups (P0.01). Ablation times were comparable in both groups. No major complications occurred.Our data show that TS and TA approaches are equal in success rate and total procedure, patient fluoroscopy, and ablation time when using the MNS for left-sided AP ablation. However, crossing the aortic valve with the MNS is faster than completing a TS puncture.

Ablation for atrioventricular nodal reentry tachycardia is very effective, with a potential for damage to the normal conduction system. Cryoablation is an alternative, as it allows cryomapping, which permits assessment of slow pathway elimination at innocent freezing temperatures, avoiding permanent damage to the normal conduction system. It is associated with shorter radiation times and the absence of heart block in all published data. We discuss in this overview different approaches of cryoenergy delivery (focusing on spot catheter ablation), and how lesion formation is influenced by catheter tip size, application duration, and freezing rate. Some advantages of cryoenergy are explained. Whether these features also apply for an approach with a cryoballoon, e.g. for atrial fibrillation is unclear.

Monomorphic ventricular tachycardia (VT) and symptomatic monomorphic PVCs originating from the region of the right mid left outflow tracts are increasingly treated by radiofrequency (RF) catheter ablation. Technical difficulties in catheter manipulation to access these outflow tract areas, very accurate mapping and reliable catheter stability are key issues for a successful treatment in this vulnerable region. VT ablation from the aortic sinus cusp (ASC) in particular carries a significant risk of perforation, of creating left coronary artery injury mid of damage to the aorta and the aortic valve. This case series describes RF ablation of VT originating in the outflow region using the remote magnetic navigation system (MNS). Potential advantages of the MNS are catheter flexibility, steering accuracy and reproducibility to navigate to a desired location with a low probability of perforating the myocardium. This report supports the idea of using advanced MNS technology during P,F ablation in regions which are difficult to reach and thin walled, such as parts of the outflow tract and the ASC. (Neth Heart J 2009; 17:245-9.)