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Background: Atrial fibrillation is a chronic, progressive disorder, and persistent forms of atrial fibrillation are associated with increased risks of thromboembolism and heart failure. Catheter ablation as initial therapy may modify the pathogenic mechanism of atrial fibrillation and alter progression to persistent atrial fibrillation., Methods: We report the 3-year follow-up of patients with paroxysmal, untreated atrial fibrillation who were enrolled in a trial in which they had been randomly assigned to undergo initial rhythm-control therapy with cryoballoon ablation or to receive antiarrhythmic drug therapy. All the patients had implantable loop recorders placed at the time of trial entry, and evaluation was conducted by means of downloaded daily recordings and in-person visits every 6 months. Data regarding the first episode of persistent atrial fibrillation (lasting ≥7 days or lasting 48 hours to 7 days but requiring cardioversion for termination), recurrent atrial tachyarrhythmia (defined as atrial fibrillation, flutter, or tachycardia lasting ≥30 seconds), the burden of atrial fibrillation (percentage of time in atrial fibrillation), quality-of-life metrics, health care utilization, and safety were collected., Results: A total of 303 patients were enrolled, with 154 patients assigned to undergo initial rhythm-control therapy with cryoballoon ablation and 149 assigned to receive antiarrhythmic drug therapy. Over 36 months of follow-up, 3 patients (1.9%) in the ablation group had an episode of persistent atrial fibrillation, as compared with 11 patients (7.4%) in the antiarrhythmic drug group (hazard ratio, 0.25; 95% confidence interval [CI], 0.09 to 0.70). Recurrent atrial tachyarrhythmia occurred in 87 patients in the ablation group (56.5%) and in 115 in the antiarrhythmic drug group (77.2%) (hazard ratio, 0.51; 95% CI, 0.38 to 0.67). The median percentage of time in atrial fibrillation was 0.00% (interquartile range, 0.00 to 0.12) in the ablation group and 0.24% (interquartile range, 0.01 to 0.94) in the antiarrhythmic drug group. At 3 years, 8 patients (5.2%) in the ablation group and 25 (16.8%) in the antiarrhythmic drug group had been hospitalized (relative risk, 0.31; 95% CI, 0.14 to 0.66). Serious adverse events occurred in 7 patients (4.5%) in the ablation group and in 15 (10.1%) in the antiarrhythmic drug group., Conclusions: Initial treatment of paroxysmal atrial fibrillation with catheter cryoballoon ablation was associated with a lower incidence of persistent atrial fibrillation or recurrent atrial tachyarrhythmia over 3 years of follow-up than initial use of antiarrhythmic drugs. (Funded by the Cardiac Arrhythmia Network of Canada and others; EARLY-AF ClinicalTrials.gov number, NCT02825979.)., (Copyright © 2022 Massachusetts Medical Society.)

Background: Outcome of ischemic VT ablation may differ between patients with previous myocardial infarction (MI) in relation to infarct localization., Methods: We analyzed procedural data, acute and long-term outcomes of 152 consecutive patients (139 men, mean age 67 ± 9 years) with previous anterior or inferior MI who underwent ischemic VT ablation at our institution between January 2010 and October 2015., Results: More patients had a history of inferior MI (58%). Mean ejection fraction was significantly lower in anterior MI patients (28 ± 10% vs. 34 ± 10%, p < 0.001). NYHA class and presence of comorbidities were not different between the groups. Indication for the procedure was electrical storm in 43% of patients, and frequent implantable cardioverter defibrillator (ICD) therapies in 57%, and did not differ significantly between anterior and inferior MI patients. A mean of 3 ± 2 VT morphologies were inducible, with a trend towards more VT in the anterior MI group (3.1 ± 2.2 vs. 2.6 ± 1.9, p = 0.18). Procedural parameters and acute success did not differ between the groups. During a mean follow-up of 3 ± 2 years, more anterior MI patients had undergone a re-ablation (49% vs. 33%, p = 0.09, Chi-square test). There was a trend towards more ICD shocks in patients with previous anterior MI (46% vs. 34%). After adjusting for risk factors and ejection fraction, multivariable Cox regression analyses showed no significant difference in mortality (p = 0.78) and cardiovascular mortality between infarct localizations (p = 0.6)., Conclusion: Clinical characteristics of patients with anterior and inferior MI are similar except for ejection fraction. Patients with inferior MI appear to have better outcome regarding survival, ICD shocks and re-ablation, but this appears to be related to better ejection fraction when compared with anterior MI.

Introduction: Left atrial flutter predominantly occurs after surgical or ablation procedures but this entity has also been recently reported in individuals without previous interventions. The use of high-density electroanatomical mapping-systems (HDM) has improved the understanding of underlying mechanisms beyond entrainment maneuvers and substrate analyses. We aimed to evaluate the mechanism of left atrial (LA) flutters in preablated vs ablation-naïve individuals and sought to assess the efficacy of empiric ablations sets in these groups., Methods and Results: We included 55 patients admitted for ablation of LA flutter between July 2017 and August 2019. On the basis of HDM analyses the arrhythmia mechanism was determined with consecutive ablation targeting the suspected critical isthmus. Mean age was 69.8 ± 10.7 years, with 26 of 55 (47.3%) male patients. Thirty-nine (71%) patients had previously undergone LA ablation. Arrhythmia mechanisms differed between preablated and ablation-naïve patients as anatomical structure-related LA flutters (perimitral, roof-dependent, within-pulmonary veins) were more frequent in the preablated cohort compared to ablation-naïve individuals (74.4% vs 43.8%; P = .03). In ablation-naïve patients, most flutters (9 of 16, 56.3%) were related to low-voltage areas at the anterior/posterior wall. Acute termination rates were high (>90%) in both groups. Empirical mitral isthmus or roof lines showed a potential higher success rate in preablated patients., Conclusion: We identified different mechanisms of LA flutters in preablated vs ablation-naïve patients. In ablation-naïve patients, most tachycardias involved low-voltage areas rather than anatomical structures. Using HDM, acute success rates were high. Hypothetical linear ablations were less successful in ablation-naïve individuals, further highlighting the need to identify the specific individual tachycardia mechanism in these patients., (© 2020 Wiley Periodicals LLC.)

Atrial fibrillation and other atrial tachyarrhythmias are increasing with age and concomitant morbidity. First options in symptomatic patients are drug treatment and catheter ablation. Nevertheless, a considerable number of patients suffer from refractory atrial tachyarrhythmias despite treatment. Atrioventricular node ablation (AVNA) may be helpful in many of these patients. Therefore, we investigated AVNA patients with a long-term follow-up. We enrolled 82 patients with a follow-up longer than 1 year receiving AVNA for drug- and ablation-resistant atrial tachyarrhythmias (AA) in a retrospective manner. Mean follow-up duration was 48 ± 24 months. 50% of the patients initially received AVNA to optimize biventricular pacing in cardiac resynchronization therapy, the other 50% because of refractory symptomatic tachyarrhythmias. Persistent AV block was achieved in every patient. Symptom relief and patient satisfaction were high during follow-up. Due to system upgrades there were 63% of patients with a biventricular system during follow-up. In these patients, left-ventricular ejection fraction (LV-EF) increased by 7% (42-49%) after ablation. AVNA is effective in increasing biventricular pacing as well as for symptom relief in patients with refractory atrial tachyarrhythmias. AVNA should be considered as a valuable option in patients with refractory atrial tachyarrhythmias lacking other treatment options.

Background: Implantable loop recorders (ILR) may be used to detect occult atrial fibrillation (AF) in patients with cryptogenic stroke. At present, there has been no description on the incidental findings of stored episodes in these patients. Furthermore, no standard practice has been established with respect to the duration of continued ECG monitoring in these patients., Materials and Methods: In the prospective monocentric study (TRACK-AF), a total of 173 patients with cryptogenic stroke received an ILR for detection of AF between November 2010 and December 2014. Before implantation all patients had undergone recommended protocols for detection of stroke causes., Results: During a mean follow-up of 24.8 ± 11.5 months, atrial tachyarrhythmias were detected in n = 33 pts (19.1%). Diagnosis of AF was made after a mean of 10.7 ± 11.4 months, time to first AF detection ranged between 0.2 and 39.8 months. In 15 patients (8.7%), other incidental findings were stored in the ILR memory. Short episodes of sinus arrest at night not requiring a permanent pacemaker were present in 8 pts (4.6%). DDD-pacemaker implantation due to sinus arrest or symptomatic bradyarrhythmias occurred in 5 patients (2.9%) after a median monitoring period of 23.1 ± 7.4 months. Further incidental findings were atrial flutter and an AV-nodal-reentry tachycardia in one patient, respectively. Both patients underwent successful catheter ablation. So far, ILR were explanted in 111 pts, and 71 ILR were explanted before end of service status of the battery. Main reason for ILR explantation was patients' preference (51%), followed by battery depletion (24%) and diagnosis of AF (15%)., Conclusion: The present study revealed a significant number of ECG findings during continued ECG monitoring for AF in patients with cryptogenic stroke. Apart from AF (17.5% during the first 1.5 years), other clinical relevant arrhythmias requiring, e.g., pacemaker implantations, were observed. With respect to these findings, we recommend to extend ILR monitoring to the end of battery life. However, acceptance of continued ECG monitoring until battery depletion was poor; in 71 patients (64%), the ILR were explanted before the end of battery life., Trial Registration: Registered at ClinicalTrials.gov: NCT02641678.

Background: The first-line therapy for atrioventricular nodal reentry tachycardia (AVNRT) is catheter-based slow pathway modulation. If AVNRT is not inducible during an electrophysiological study, an empirical slow pathway modulation (ESPM) may be considered in patients with dual atrioventricular nodal physiology and/or a typical electrocardiogram (ECG)., Methods: We screened 149 symptomatic patients who underwent ESPM in our department between 1993 and 2013. All patients fulfilled the following criteria: (1) either dual atrioventricular nodal (AVN) physiology with up to 2 AVN echo beats or characteristic ECG documentation or both, (2) noninducibility of AVNRT by programmed stimulation, and (3) completion of a telephone questionnaire for long-term follow-up. Out of this population we retrospectively investigated 13 patients who were primarily noninducible but in whom an AVNRT occurred during or after radiofrequency (RF) delivery., Results: When AVNRT occurred, the procedure lost its empirical character, and RF delivery was continued until the procedural endpoint of noninducibility of AVNRT. This endpoint was reached in all but one patient (92%). After a follow-up of 73 ± 15 months, this patient was the only one who reported no benefit from the procedure., Conclusions: Out of 149 initially noninducible patients, a considerable number (9%) exhibited AVNRT during or after RF delivery. These patients crossed over from empirical to controlled slow pathway modulation resulting in a good clinical outcome. Our observations should encourage electrophysiologists to repeat programmed stimulation even after initial empirical RF delivery to retest for inducibility., (© 2017 Wiley Periodicals, Inc.)

Objectives: This study sought to evaluate the spatial relationships of focal electrical sources (FSs) to complex fractionated atrial electrograms (CFAE) and continuous electrical activity (CEA)., Background: Fractionated atrial electrograms have been associated with atrial fibrillation (AF) drivers in computational studies and represent ablation targets in the management of persistent AF., Methods: We included a subset of 66 patients (age: 63 [56, 67] years, 69% persistent AF) with electroanatomic data from the SELECT AF (Selective complex fractionated atrial electrograms targeting for atrial fibrillation) randomized control trial that compared the efficacy of CFAE with CEA ablation in AF patients undergoing pulmonary vein antral ablation. Focal sources were identified based on bipolar electrogram periodicity and QS unipolar electrogram morphology., Results: A total of 77 FSs (median: 1 [1st quartile, 3rd quartile: 1, 2] per patient) were identified most commonly in the pulmonary vein antrum and left atrial appendage. The proportions of FSs inside CFAE and CEA regions were similar (13% vs. 1.3%, respectively; p = 0.13). Focal sources were more likely to be on the border zone of CFAEs than in CEAs (49% vs. 7.8%, respectively; p = 0.012). Following ablation, 53% of patients had ≥1 unablated extrapulmonary vein FS. The median number of unablated FS was higher in patients with AF recurrence post ablation than in patients without (median: 1 [0, 1] vs. 0 [0, 1], respectively; p = 0.026)., Conclusions: One-half of the FSs detected during AF localized to the border of CFAE areas, whereas most of the FSs were found outside CEA areas. CFAE or CEA ablation leaves a number of FS unablated, which is associated with AF recurrence. These findings suggest that many CFAEs may arise from passive wave propagation, remote from FS, which may limit their therapeutic efficacy in AF substrate modification., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Permanent AV-block is a recognized and feared complication of slow pathway modulation for AVNRT. We aimed to assess incidence of transient and permanent AV-block as well as consequences of transient AV-block in a large contemporary AVNRT ablation cohort., Methods: We searched our single center prospective ablation database for occurrence of transient and permanent AV-block during slow pathway modulation between January 2004 and October 2015. We analyzed patients' and procedural characteristics as well as outcome of patients in whom transient or permanent AV-block occurred., Results: Of 9170 patients who underwent a catheter ablation at our institution between January 2004 and October 2015, 2101 patients (64% women, mean age 50±18years) underwent slow pathway modulation. In three patients, permanent AV-block occurred during RF application. Additional two patients had transient AV-block that recovered (after a few minutes and 25min), but recurred within two days of the procedure. All five patients underwent dual chamber pacemaker implantation (0.2%). Transient AV-block related to RF delivery occurred in 44 patients (2%). Transient mechanical AV-block occurred in additional 17 patients (0.8%). In 12 patients, ablation was continued despite transient AV-block. One of these patients developed permanent AV-block., Conclusion: Permanent AV-block following slow pathway modulation is a rare event, occurring in 0.2% of patients in a large contemporary single center cohort. Transient AV-block is more frequent (2%)., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Controversy exists about the impact of acute atrial fibrillation (AF) termination and prolongation of atrial fibrillation cycle length (AFCL) during ablation on long-term procedural outcome., Objective: The purpose of this study was to analyze the influence of AF termination and AFCL prolongation on freedom from AF in patients from the STAR AF II (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial-Part II) trial., Methods: Acute changes in AFCL and AF termination were collected during the index procedure of the STAR AF II trial and compared to recurrence of AF at 18 months. Recurrence was assessed by ECG, Holter (3, 6, 9, 12, 18 months), and weekly transtelephonic ECG monitoring for 18 months., Results: AF terminated in 8% of the pulmonary vein isolation (PVI) arm, 45% in the PVI+complex electrogram arm, and 22% of the PVI+linear ablation arm (P <.001), but freedom from AF did not differ among the 3 groups (P = .15). Freedom from AF was significantly higher in patients who presented to the laboratory in sinus rhythm (SR) compared to those without AF termination (63% vs 44%, P = .007). Patients with AF termination had an intermediate outcome (53%) that was not significantly different from those in SR (P = .84) or those who did not terminate (P = .08). AF termination was a univariable predictor of success (P = .007), but by multivariable analysis, presence of early SR was the strongest predictor of success (hazard ratio 0.67, P = .004). Prolongation of AFCL was not predictive of 18-month freedom from AF., Conclusion: Acute AF termination and prolongation in AFCL did not consistently predict 18-month freedom from AF. Presence of SR before or early during the ablation was the strongest predictor of better outcome., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Because of the unclear prognostic effects of ablation of atrial fibrillation (AF), oral anticoagulation (OAC) is often continued after ablation even in asymptomatic patients. We sought to determine the frequency of stroke and AF recurrence in patients on and off therapeutic OAC 1 year after a successful AF ablation., Methods and Results: Patients that underwent AF ablation and were free of AF 12 months after ablation were selected from our AF database. During follow-up (FU), patients were screened for recurrence of AF, changes in OAC or antiarrhythmic medication, and the occurrence of stroke or transient ischemic attack (TIA). A total of 398 patients (median age 60.7 years [50.8, 66.8], 25% female) were investigated. The median duration of FU was 529 (373, 111,3.5) days. OAC was discontinued in 276 patients (69.3%). During FU, 4 patients (1%) suffered from stroke and 55 patients (13.8%) experienced a recurrence of AF. Persistent AF was significantly associated with a greater chance of AF recurrence (49.1% vs. 26.8%; P = 0.001). Neither CHADS 2 nor CHA2DS2-VASc-Score nor recurrence of AF were significantly different in patients with or without stroke. There was a trend toward a higher percentage of coronary artery disease among patients that experienced stroke (50% vs. 10%; P = 0.057)., Conclusion: The overall risk of stroke and AF recurrence is low in patients with a recurrence free interval of at least 12 months after AF ablation. Of note, recurrence of AF was not associated with a higher risk of stroke in our study population., (© 2016 Wiley Periodicals, Inc.)

Background: Slow pathway modification (SPM) is the therapy of choice for AV-nodal reentry tachycardia (AVNRT). When AVNRT is not inducible, empirical ablation can be considered, however, the outcome in patients with two AV nodal echo beats (AVNEBs) is unknown., Methods: Out of a population of 3003 patients who underwent slow pathway modification at our institution between 1993 and 2013, we retrospectively included 32 patients with a history of symptomatic tachycardia, lack of paroxysmal supraventricular tachycardia (pSVT) inducibility but occurrence of two AVNEBs., Results: pSVT documentation by electrocardiography (ECG) was present in 20 patients. The procedural endpoint was inducibility of less than two AVNEBs. This was reached in 31 (97%) patients. Long-term success was assessed by a telephone questionnaire (follow-up time 63±9 months). A total 94% of the patients benefited from the procedure (59% freedom from symptoms; 34% improvement in symptoms). Among those patients in whom ECG documentation was not present, 100% benefited (58% freedom from symptoms, 42% improvement)., Conclusion: This is the first collective analysis of a group of patients presenting with symptoms of pSVT and inducibility of only two AVNEBs. Procedural success and clinical long-term follow-up were in the range of the reported success rates of slow pathway modification of inducible AVNRT, independent of whether ECG documentation was present. Thus, SPM is a safe and effective therapy in patients with two AVNEBs., (Copyright © 2016. Published by Elsevier Ltd.)

Background: Success rates of atrial fibrillation (AF) ablation have been shown to be significantly lower for patients with persistent AF. However, little is known about the risk factors predicting progression to persistent AF in patients awaiting AF ablation., Methods: We performed a retrospective, single-centre investigation of patients with paroxysmal AF at the time of placement on the ablation waiting list. Patients were defined as having progressed if they had developed self-reported or electrocardiogram-recorded AF durations more than 7 days while awaiting ablation. After ablation, clinical visits at 3, 6, 9, 12, and 18 months were performed with a minimum of a 48-hour-Holter and electrocardiogram. Baseline characteristics including left atrial diameter (LA) and the HATCH score were analyzed by univariable and multivariable analysis for predicting progression to persistent AF., Results: During a median waiting time of 9.7 (6.1, 14.2) months, 60 of 564 patients (11%) progressed to persistent AF. In patients who progressed, ablation took longer (180 [150, 249] minutes vs 157 [125, 210] minutes; P = 0.009) and was associated with a higher rate of recurrence after a median of 12 months (53.3% vs 39.1%; P < 0.001). The HATCH score was a poor predictor of AF progression (area under the curve 0.54), whereas an LA diameter of more than 45 mm (odds ratio 3.46, P < 0.001) and heart failure (odds ratio 3.11, P = 0.036) were strong and independent predictors of AF progression in multivariable analysis., Conclusions: Patients with an increased LA diameter or heart failure have a significantly increased risk of progression to persistent AF. These characteristics may define patients who should undergo earlier catheter ablation to optimize outcome., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Assumption of different substrates is the basis for different ablation strategies in patients with paroxysmal and persistent atrial fibrillation (AF). We aimed to investigate pulmonary vein reconnection and influence on progression of initial paroxysmal (pAF) versus persistent atrial fibrillation (perAF)., Methods: Between January 2010 and November 2012, 149 patients (117 men, mean age 59 ± 11 years, range 27-80 years) underwent at least one redo antral pulmonary vein isolation (PVI) using NavX-guided irrigated-tip radiofrequency catheter ablation. We analyzed whether and where reconnection of pulmonary veins was detected, and whether there were differences between patients with pAF and perAF., Results: Of the 149 patients who underwent a redo antral PVI, 80 patients had pAF and 69 had perAF. One, two and three redo PVIs were performed in 149, 26 and 6 patients, respectively. Reconnection of at least one PV was detected in all patients at the second PVI, in 19 of 26 patients (73 %) at the third PVI and 5 of 6 patients (83 %) at the fourth PVI. 20 (29 %) patients with perAF prior to the first PVI had pAF at the second PVI, whereas 15 (19 %) patients with initial pAF had persistent AF at the time of the first redo procedure. From the second to the third PVI, four patients had developed perAF after previous pAF and two with per AF now had pAF. PV reconnection was observed independent of underlying AF type. At the second redo procedure, of those with reconnected veins 12 had pAF and 13 perAF. At the third redo procedure, four patients had pAF and four perAF., Conclusion: Most patients with recurrent AF after PVI showed at least one reconnected vein during redo procedures. Reconnection was identified irrespective of the underlying AF type. Progression from pAF to perAF and vice versa was observed irrespective of the initial AF type.

Aims: The second-generation multi-electrode-phased radiofrequency pulmonary vein ablation catheter (PVAC GOLD(®)) was redesigned with the intent to improve its safety and efficacy., Methods and Results: Using a prospectively designed single-centre database, we retrospectively analysed 128 consecutive patients (102 paroxysmal and 43 female) who underwent their first pulmonary vein isolation with the PVAC GOLD(®). The analysis focused on procedural data as well as in-hospital complications. Baseline characteristics of the patient collective were as follows: mean age 57.9 years, mean CHA2DS2-VASC was 1.73 ± 1.30; structural heart disease was present in seven patients. The PVAC GOLD(®) exhibited procedure durations of 123.1 min ± 27.9, duration of energy delivery was 18.3 min ± 11.4, and fluoroscopy duration was 16.0 min ± 7.7. The redesigned catheter shows major complication [major bleeding, transitory ischaemic attack (TIA), and pericardial tamponade] rates of 2.3% (n = 3). The overall rate of adverse events was 5.4% (n = 7). Bleeding complications were observed in three patients (2.3%), in particular there were two cases (1.6%) of minor bleeding and one case (0.8%) of major bleeding. Two patients suffered pericardial effusion, but there was no need for pericardiocentesis. Besides one TIA, there was no other thrombo-embolic event. Furthermore, one case of post-procedural fever was observed. No deaths, stroke, or haemorrhagic shock occurred. Of the 510 pulmonary veins, 508 could be reached with the PVAC GOLD(®) device using a non-steerable long sheath., Conclusion: The PVAC GOLD(®) seems to have an acceptable safety profile. The handling is comparable with the previous generation PVAC(®)., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Objective: Catheter-based modulation of the slow pathway is the first-line therapy of atrioventricular nodal reentrant tachycardia (AVNRT), the most common supraventricular tachycardia (SVT). In patients with a typical history, in whom AVNRT is not inducible during an electrophysiological study, the current guidelines allow consideration of empirical slow pathway modulation (ESPM) under the precondition that both, dual nodal pathway physiology (DNPP) and an ECG documentation compatible with AVNRT exist. This recommendation is based on small series. Furthermore, it is unknown whether ESPM is beneficial in the presence of ECG documentation but the absence of DNPP or vice versa in the presence of DNPP but absence of ECG documentation., Methods: Out of 3003 patients who underwent slow pathway modulation from 1993 to 2013, we included 116 patients (68 female; median age 47.0 years) with symptomatic tachycardia who had non-inducible SVT. All patients either had ECG documentation of SVT (66 %) or DNPP (89 %) or both (54 %). All patients underwent ESPM. No severe complications occurred., Results: After a follow-up time of 64 ± 5.3 months, 81 % of all patients had benefited from ESPM (49 % freedom of symptoms, 32 % improvement). In patients with ECG documentation but absence of DNPP 100 % benefited (85 % freedom of symptoms; 15 % improvement). In patients with DNPP but absence of ECG documentation 75 % benefited (40 % freedom of symptoms, 35 % improvement)., Conclusion: In a large cohort of patients, ESPM is a safe procedure that improves clinical symptoms in the majority of patients during long-term follow-up. We show for the first time that this also applies for cases where there is no DNPP but a characteristic ECG documentation, and vice versa.

Background: Clinically silent lesions on cerebral magnet resonance imaging have been found in larger numbers after pulmonary vein isolation (PVI) especially with phased radio frequency (pRF) using all ten electrodes. However, the neuropsychological effects of cerebral microembolism during the procedure remain unclear and data regarding this issue so far are inconsistent., Methods: Between August 2011 and June 2012, 76 patients undergoing their first PVI were randomized to ablation with either phased (40) or irrigated (36) radio frequency (iRF). A comprehensive neuropsychological test battery was performed the day before and after PVI as well as 6 months after ablation. The occurrence of cerebral microemboli during the procedure was performed via a transcranial Doppler ultrasound device., Results: PVI using pRF was associated with increased number of microembolic signals (MES) compared to iRF (1530.0 ± 979.8 vs. 645.7 ± 448.7; p < 0.001). Neuropsychological assessment did not reveal any changes in correlation with the used ablation technique. Besides an age-related effect there was a diffuse, sub-clinical impairment of neurologic function depending on age and the number of MES., Conclusions: There was no clinical overt cognitive deficit and no significant difference in cognitive function correlating with the used ablation technique. The number of MES correlated with a subtle, diffuse post-procedural impairment of neuropsychological function highlighting the need to reduce microemboli during ablation.

Ablation therapy for atrial fibrillation (AF) has been shown to be more efficient than medical treatment alone. Long-term success of AF ablation is still around 50% after one ablation and higher after two, with a substantial amount of asymptomatic recurrences in formerly symptomatic patients. Given the lack of evidence for superiority of rhythm control over rate control in terms of stroke reduction and mortality, AF ablation remains a treatment for symptom reduction only, although ablation has never been a part of these studies. There is early evidence that ablation could decrease the long-term risk of stroke; however, prospective studies are needed to assess whether this is the case and how patients with a successful ablation can be identified. If AF ablation can be shown to improve long-term morbidity, it could also become a reasonable treatment for patients with asymptomatic AF.

Background: There is a paucity of data that compare traditional vitamin K antagonist (VKA) with novel oral anticoagulant regimens in periprocedural management of cardioversion or ablation of atrial fibrillation (AF). We sought to compare outcomes of use of VKA, dabigatran (DABI), and rivaroxaban (RIVA) anticoagulation around the time of intervention., Methods: We studied consecutive patients undergoing cardioversion or ablation of AF at our centre from October 2010 to October 2013. There were 3 different anticoagulation groups: warfarin (VKA), DABI, and RIVA. Safety was assessed according to number of strokes, transient ischemic attacks (TIAs), and clinically important and not important bleeding events., Results: Baseline characteristics were well balanced between the groups. Average follow-up was 6 months (± 4 months). A total of 901 patients who underwent cardioversion were studied (VKA [n = 471], DABI [n = 288] and RIVA [n = 141]). In these patients there were no strokes seen during follow-up and 2 TIAs in the DABI group. Bleeding rates were low, with no significant difference between the 3 groups. A total of 680 patients who underwent ablation were studied (VKA [n = 319], DABI [n = 220] and RIVA [n = 171]). There were no strokes reported during follow-up and 3 TIAs: 2 in the VKA group and 1 in the DABI group not resulting in a significant difference between the groups. Bleeding rates were low, with no significant difference between the groups., Conclusions: Overall, there was a low incidence of adverse events for all anticoagulation regimens. Warfarin, DABI, and RIVA use around the time of the procedure are safe and reasonable options for patients who undergo cardioversion or AF ablation., (Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Electrical storm is an increasingly recognized clinical entity. It is generally defined as the occurrence of ≥ 3 episodes of potentially life-threatening ventricular arrhythmias during a time span of 24 h. Apart from pharmacological treatment options, catheter ablation remains a relatively novel, promising addition to the armamentarium of the cardiologist. Here, we will review the study data on ablation of patients with electrical storm.

Aims: Phased radiofrequency (RF) ablation for atrial fibrillation is associated with an increased number of silent cerebral lesions on magnetic resonance imaging and cerebral microembolic signals (MESs) on transcranial Doppler ultrasound imaging compared with irrigated RF. The increased rate of embolic events may be due to a specific electrical interference of ablation electrodes attributed to the catheter design. The purpose of this study was to elucidate the effect of deactivating the culprit electrodes on cerebral MESs., Methods and Results: Twenty-nine consecutive patients (60 ± 11 years, 10 female) underwent their first pulmonary vein isolation using phased RF energy. Electrode pairs 1 or 5 were deactivated to avoid electrical interference between electrodes 1 and 10 ('modified'). Detection of MESs by transcranial Doppler ultrasound was performed throughout the procedure to assess cerebral microembolism. Results were compared with the numbers of MESs in 31 patients ablated using all available electrodes ('conventional') and to 30 patients undergoing irrigated RF ablation of a previous randomized study. Ablation with 'modified' phased RF was associated with a marked decrease in MESs when compared with 'conventional' phased RF (566 ± 332 vs. 1530 ± 980; P < 0.001). This difference was mainly triggered by the reduction of MES during delivery of phased RF energy, resulting in MES numbers comparable to irrigated RF ablation (646 ± 449; P = 0.7). Total procedure duration as well as time of RF delivery was comparable between phased RF groups. Both times, however, were significantly shorter compared with the irrigated RF group (123 ± 28 vs. 195 ± 38; 15 ± 4 vs. 30 ± 9; P < 0.001, respectively)., Conclusion: Pulmonary vein isolation with 'modified' phased RF is associated with a decreased number of cerebral microembolism especially during the delivery of ablation impulses, supporting the significance of electrical interference between ablation electrodes 1 and 10. Deactivation of electrode pairs 1 or 5 might increase the safety of this approach without an increase in procedure duration or RF delivery time.

Background: Symptomatic, premature ventricular contractions (PVCs) frequently originate in the right ventricular outflow tract, less frequently in the left ventricular outflow tract, aortic root, or mitral annulus (MA). Little is known about the patient population presenting with MA PVC and/or ventricular tachycardia (VT)., Objective: To characterize the subgroup of ventricular arrhythmias arising from the MA., Methods: Among 404 consecutive patients who presented for catheter ablation of idiopathic PVC/VT over a period of 9 years, patients who were found to have an ablation site at the MA were analyzed for clinical and electrophysiological parameters., Results: Twenty-two (5%) patients (mean age 45 ± 18 years; range 16-76 years; 14 [64%] men) had PVC/VT arising from the MA. History of PVC ranged from 2 days in a case with suspected focal myocarditis to 19 years. No patient had severely depressed left ventricular function or significant heart disease, which was determined by echocardiogram, magnetic resonance imaging, and/or coronary angiogram. Sites of origin were distributed around the MA with no preferential area. Ablation was successful in 13 of 16 (81%) patients. One 28-year-old female patient with normal magnetic resonance imaging and no structural heart disease died suddenly 3 months after ablation., Conclusions: Ventricular arrhythmias from the MA represent a rare subgroup of idiopathic PVC/VT. They appear to occur at any age and do not indicate underlying structural heart disease. Catheter ablation has a success rate comparable to that of outflow tract tachycardia. Prognosis remains unclear., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Recent evidence suggests that cardiac sarcoidosis (CS) and arrhythmogenic right ventricular cardiomyopathy (ARVC) can manifest very similarly., Objective: To investigate whether there are significant demographic and electrophysiological differences between patients with CS and ARVC., Methods: We prospectively compared patients with proven CS or ARVC who underwent radiofrequency catheter ablation of ventricular tachycardias by using 3-dimensional electroanatomical mapping. Furthermore, we evaluated whether the diagnostic criteria for ARVC would have excluded ARVC in patients with CS., Results: Eighteen patients (13 men; mean age 44.9 years) were included. All 18 patients had mild to moderately reduced right ventricular ejection fraction. Patients with cardiac sarcoidosis (n = 8) had a significantly lower mean left ventricular ejection fraction (35.6±19.3 vs 60.6±9.4; P = .002). Patients with CS had a significantly wider QRS (0.146 vs 0.110s; P = .004). Five of 8 (63%) patients with CS fulfilled the diagnostic ARVC criteria. Ventricular tachycardias (VTs) with a left bundle branch block pattern were documented in all but one patient (with CS). Programmed ventricular stimulation induced an average of 3.7 different monomorphic VTs in patients with CS vs 1.8 in patients with ARVC (P = .01). VT significantly more often originated in the apical region of the right ventricle in CS vs ARVC (P = .001), with no other predilection sites. Ablation success and other electrophysiological parameters were not different., Conclusions: The current diagnostic ARVC guidelines do not reliably exclude patients with CS. Clinical and electrophysiological parameters that were characteristic of CS in our patients include reduced left ventricular ejection fraction, a significantly wider QRS, right-sided apical VT, and more inducible forms of monomorphic VT., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Electrophysiologic characteristics, mapping strategies, and acute success rates of radiofrequency catheter ablation of atriofascicular accessory pathways are well described. However, data on long-term prognosis and predictors for freedom from arrhythmias are lacking., Objective: To report our 20-year single-center experience on ablation of atriofascicular fibers., Method: Between 1992 and 2010, 34 patients with atriofascicular accessory pathways underwent catheter ablation at our institution because of symptomatic antidromic atrioventricular reentrant tachycardias. Radiofrequency procedures were retrospectively analyzed, and patients were followed for recurrences of tachyarrhythmias. Electrocardiograms (before and after ablation and at follow-up) were analyzed for each patient., Results: Successful catheter ablation of the atriofascicular fiber was achieved in 23 (68%) patients. Mechanical block during mapping occurred in 3 (9%) patients, and in 2 of them ablation was performed at the site of mechanical block. Mere modification of conduction properties of the pathway without complete block was achieved in 5 patients (15%). Fast pathway ablation was performed in 2 (6%) of the patients ablated in the early 1990s. During follow-up of 9.3 ± 5.5 years, 24 patients (71%) remained free of tachyarrhythmias, 7 reported significant improvement, and 3 (9%) had no change in symptoms after ablation. Long-term success was identical between patients from the first (1992-1999) and second (2000-2010) decade (12 of 17 [71%] vs 12 of 17 [71%]). It was 87% in those with complete block of the atriofascicular fiber while all patients with mechanical block during mapping reported recurrences. Fast pathway ablation was complicated by complete atrioventricular block in 1 patient, who required pacemaker implantation 18 years after ablation owing to loss of conduction properties of the atriofascicular fiber over the years. On analyzing patients with preexcitation before ablation (n = 16; 47%), we found that the PR interval after ablation was significantly longer only in those without recurrence (162 ± 21 ms vs 134 ± 21 ms; P = .042). None of the other analyzed electrocardiographic parameters, including PR, QRS duration, and preexcitation, had prognostic impact., Conclusion: Acute success of complete ablation of atriofascicular pathways is associated with excellent long-term success (87%). Mere modification of conduction properties of atriofascicular fibers or ablation at the sites of mechanical block are less promising end points of ablation with high recurrence rates. Technical innovations during decades may not further improve long-term outcome in these patients., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)