Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation for which the left atrium (LA) is usually accessed by the antegrade femoral venous route and transseptal puncture. However, in rare cases, alternative routes must be used to overcome anatomical challenges. A retrograde approach via the femoral artery and by subsequently passing the aortic and mitral valve is virtually impossible using conventional catheters. Purpose To investigate the feasibility of a retrograde approach for AF ablation by robotic magnetic navigation (RMN) using floppy radiofrequency ablation catheters. Methods Between June 2014 and December 2021, a total of 6 consecutive patients underwent a total of 8 ablation procedures for AF by retrograde approach using a RMN at tour center. A magnetic catheter was introduced through the right femoral artery and manually advanced retrogradely to the aortic arch. Thereafter, it was further advanced to the LA using RMN by switching the magnets to navigation mode, passing through both aortic and mitral valve (Figure 1). Circumferential PVI was performed by antral point-by-point radiofrequency ablation and additional atrial lines were targeted when deemed necessary. Bidirectional conduction block was proven by loss of pulmonary vein potentials on the ablation catheter which automatically moved in a radial manner collecting 16 mapping points. Results The patient group (Figure 2) consisted of 4 females and 2 males with a mean age of 58,0±10,8years. 4 patients (67%) presented with persistent AF. The mean time between diagnosis and catheter ablation was 5,3±3,5 years. 2 patients (33%) had an acquired mechanical obstruction of the conventional transseptal route. The other 4 patients (67%) had an anatomical abnormality precluding conventional access to the LA. These 4 patients all underwent an unsuccessful ablation attempt via conventional approach elsewhere, before referral to our center. Patients 3 and 4 also underwent an epicardial ablation for AF respectively 1,3 and 6,2 years before catheter ablation using RMN. Patient 3 also underwent a failed attempt on manual catheter ablation using the retrograde route in another center. AF catheter ablation via retrograde access using RMN was possible in all patients and no complications occurred. The mean follow-up was 3,4±3,3 years. Conclusion Our findings indicate that a retrograde transaortic approach for catheter ablation in AF using magnetic navigation system and electroanatomical mapping is technically feasible and safe in patients with anatomical challenges precluding the use of a conventional antegrade transseptal approach. This technique may serve as an indispensable component of the management of this subgroup of patients in experienced centers.

Background: Adding electroanatomical left atrial (LA) voltage mapping to cryoballoon ablation (CBA) improves validation of acute pulmonary vein isolation (PVI). Aims: To determine whether the addition of mapping can improve outcome and PVI durability. Methods: One-year outcome and PV reconnection (PVR) rate at first repeat ablation were studied in 400 AF patients in a propensity-matched analysis (age, AF type, CHA2DS2-VASc score) between Achieve catheter-guided CBA with additional EnSite LA voltage maps performed pre- and post-CBA (mapping group; N = 200) and CT- and Achieve catheter-guided CBA (control group; N = 200). Clinical success was defined as freedom of documented AF or atrial tachycardia (AT) > 30 s. PV reconnection patterns were characterized in repeat ablations. Results: At 1 year, 77 (19.25%) patients had recurrence of AF/AT, significantly lower than in the mapping group: 21 (10.5%) vs. 56 (28%), p < 0.001. Procedure time was shorter (72.2 ± 25.4 vs. 78.2 ± 29.3 min, p = 0.034) and radiation exposure lower (4465.0 ± 3454.6 Gy.cm2 vs. 5940.5 ± 4290.5 Gy.cm2, p = 0.037). Use of mapping was protective towards AF/AT recurrence (HR = 0.348; 95% CI 0.210–0.579; p < 0.001), independent of persistent AF type (HR = 1.723; 95% CI 1.034–2.872; p = 0.037), and LA diameter (HR = 1.055; 95% CI 1.015–1.096; p = 0.006). At repeat ablation (N = 90), persistent complete PVI was seen in 14/20 (70.0%) versus 23/70 (32.9%) in the mapping and conventional group, respectively (p = 0.03). Reconnection rate of the right inferior PV was lower with mapping (10.0% vs. 34,3%, p = 0.035). Conclusions: Adding electroanatomical LA voltage mapping to CBA improves 1-year clinical outcome and lowers both procedure time and radiation exposure. At repeat, use of mapping increases complete persistent PVI mainly by improving PVI durability of the RIPV.

Introduction: Repetitive focal and rotational activation patterns are currently used as additional ablation targets for atrial fibrillation (AF). However, there is no evidence that all these detected targets are actual sources of AF. In this paper, we present an approach that detects and ranks AF activation patterns not only based on the degree of pattern repetitiveness but also on the extent to which they are able to entrain their vicinity. This new technique might enable selecting the site with the highest probability of being a source for AF. Methods: We retrospectively analyzed high-density bi-atrial sequential mapping in ablation-naive persistent AF patients (n = 13, PentaRay catheter, 30s recordings). Repetitive focal and rotational activation patterns were detected based on local activation time annotation of unipolar electrograms. The spatial stability was determined as local repetitive pattern duration. The entrainment capability was defined as the average time a directionally coherent repetitive activation pattern was observed in adjacent recordings. Results: A total of 459 recordings were analyzed (35 +/- 5 per patient). We detected 131 repetitive focal (10 +/- 4 per patient) and 56 rotational activation patterns (4 +/- 3 per patient) in total. Focal patterns were more repetitive than rotational patterns (median [IQR] 0.7 [0.4-1.3] seconds vs. 0.5 [0.4-0.6] seconds, p < 0.001 Mann-Whitney U test). By applying a 90th percentile threshold to both local and directionally coherent adjacent repetitiveness, we identified 10 sites (9 focal and 1 rotational) in 7 patients as the most probable sources. The majority of these sites were in the upper right atrium or left pulmonary vein region. Notably, in 6 patients (46 %), no probable sources were detected using this threshold. Conclusion: This study introduces a novel technique to select the repetitive focal or rotational pattern with the highest probability of being a source. We observed that only a minority of repetitive focal or rotational patterns seem to be able to entrain their vicinity and thereby are likely to serve as sources of AF.

Aims The added value of advanced practitioner nurse (APN) care after ablation of atrial fibrillation (AF) is unknown. The present study investigates the impact of APN-led care on AF recurrence, patient knowledge, lifestyle, and patient satisfaction. Methods and results Sixty-five patients undergoing AF ablation were prospectively randomized to usual care (N = 33) or intervention (N = 32) group. In addition to usual care, the intervention consisted of an educational session, three consultations spread over 6 months and telephone accessibility coordinated by the APN. Primary outcome was the AF recurrence rate at 6-month follow-up. Secondary outcomes were lifestyle factors (alcohol intake, exercise, BMI, smoking), patient satisfaction and AF knowledge measured at 1 and 6 months between groups and within each group. Study demographics at 1 month were similar, except AF knowledge was higher in the intervention group (8.6 vs. 7, P = 0.001). At 6 months, AF recurrence was significantly lower in the intervention group (13.5 vs. 39.4%, P = 0.014). Between groups, patient satisfaction and AF knowledge were significantly higher in the intervention group, respectively, 9.4 vs. 8.7 (P < 0.001) and 8.6 vs. 7.0 out of 10 (P < 0.001). Within the intervention group, alcohol intake decreased from 3.9 to 2.6 units per week (P = 0.031) and physical activity increased from 224.4 +/- 210.7 to 283.8 +/- 169.3 (P = 0.048). No changes occurred within the usual care group. Assignment to the intervention group was the only protective factor for AF recurrence [Exp(B) 0.299, P = 0.04] in multivariable-adjusted analysis. Conclusion Adding APN-led care after ablation of AF improves short-term clinical outcome, patient satisfaction and physical activity and decreases alcohol intake. Lay Summary The present study investigates the added value of advanced practitioner nurse (APN)-led care consisting of an educational session, three consultations spread over 6 months and telephone accessibility coordinated by the APN in patients after ablation of atrial fibrillation (AF). Main findings areThe addition of nurse-led care after ablation of AF improves short-term clinical outcome, patient satisfaction and physical activity and decreases alcohol intake.Our study shows that integrating nurse-led care in the post-AF ablation setting is a relatively simple to implement, low-cost intervention with a major impact on patient outcomes and quality of care. These findings encourage including nurse-led care into routine AF ablation follow-up.

BACKGROUND: In patients with persistent atrial fibrillation (PersAF), catheter ablation aiming for pulmonary vein isolation (PVI) is associated with moderate clinical effectiveness. We investigated the benefit of continuing previously ineffective class 1C or 3 antiarrhythmic drug therapy (ADT) in the setting of a standardized PVI-only ablation strategy. METHODS: In this multicenter, randomized controlled study, patients with PersAF (≥7 days and <12 months) despite ADT were prospectively randomized 1:1 to PVI with ADT continued versus discontinued beyond the blanking period (ADT ON versus ADT OFF). Standardized catheter ablation was performed aiming for durable isolation with stable, contiguous, and optimized radio frequency applications encircling the pulmonary veins (CLOSE protocol). Clinical visits and 1-to-7-day Holter were performed at 3, 6, and 12 months. The primary end point was any documented atrial tachyarrhythmia lasting >30 seconds beyond 3 months. Prospectively defined secondary end points included repeat ablations, unscheduled arrhythmia-related visits, and quality of life among groups. RESULTS: Of 200 PersAF patients, 98 were assigned to ADT OFF and 102 to ADT ON. The longest atrial fibrillation episode qualifying for PersAF was 28 (10–90) versus 30 (11–90) days. Clinical characteristics and procedural characteristics were similar. Recurrence of atrial tachyarrhythmia was comparable in both groups (20% OFF versus 21.2% ON). No differences were observed in repeat ablations and unscheduled arrhythmia-related visits. Marked improvement in quality of life was observed in both groups. CONCLUSIONS: In patients with PersAF, there is no benefit in continuing previously ineffective ADT beyond the blanking period after catheter ablation. The high success rate of PVI-only might be explained by the high rate of durable isolation after optimized PVI and the early stage of PersAF (POWDER-AF2). REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03437356.

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. 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 < 0.0001). Phrenic nerve palsy occurred in 8 (8.5%) patients and always resolved during the procedure without affecting procedural outcome. Two major complications occurred (2.1%); one patient experienced pneumonia, successfully treated with antibiotics and non-invasive mechanical ventilation, the latter one experienced acute kidney failure secondary to urosepsis successfully treated by renal replacement therapy. The present study showed that CB-A is a feasible and effective procedure among octogenarians with a low complication rate. Contemporarily, CB-A can help to alleviate arrhythmia-related symptoms also among this group of subjects.

AIMSCatheter ablation of paroxysmal atrial fibrillation (AF) reduces AF recurrence, AF burden, and improves quality of life. Data on clinical and procedural predictors of arrhythmia recurrence are scarce and are flawed by the high rate of pulmonary vein reconnection evidenced during repeat procedures after pulmonary vein isolation (PVI). In this study, we identified clinical and procedural predictors for AF recurrence 1 year after CLOSE-guided PVI, as this strategy has been associated with an increased PVI durability.METHODS AND RESULTSPatients with paroxysmal AF, who received CLOSE-guided PVI and who participated in a prospective trial in our centre, were included in this study. Uni- and multivariate models were plotted to find clinical and procedural predictors for AF recurrence within 1 year. Three hundred twenty-five patients with a mean age of 63 years (CHA2DS2VASc 1 [1-3], left atrium diameter 41 ± 6 mm) were included. About 60.9% were male individuals. After 1 year, AF recurrence occurred in 10.5% of patients. In a binary logistic regression analysis, the diagnosis-to-ablation time (DAT) was found to be the strongest predictor of AF recurrence (P = 0.011). Diagnosis-to-ablation time ≥1 year was associated with a nearly two-fold increased risk for developing AF recurrence.CONCLUSIONThe DAT is the most important predictor of arrhythmia recurrence in low-risk patients treated with durable pulmonary vein isolation for paroxysmal AF. Whether reducing the DAT could improve long-term outcomes should be investigated in another trial.

Background: Atrial fibrillation ablation–related atrial tachycardia (AT) is complex and may demonstrate several forms: anatomic macroreentrant AT (AMAT), non-AMAT, and focal AT. We aimed to elucidate the recurrence rate and mechanisms of atrial fibrillation ablation–related AT recurrence. Methods: Among 147 patients with ATs treated with the Rhythmia system, 68 (46.3%) had recurrence at mean 4.2 (2.9–11.6) months, and 44 patients received a redo procedure. AT circuits in the first procedure were compared with those in the redo procedure. Results: Although mappable ATs were not observed in 7 patients, 68 ATs were observed in 37 patients during the first procedure: perimitral flutter (PMF) in 26 patients, roof-dependent macroreentrant AT (RMAT) in 18, peritricuspid flutter in 10, non-AMAT in 14, and focal AT in 3. During the redo AT ablation procedure, 54 ATs were observed in 41/44 patients: PMF in 24, RMAT in 14, peritricuspid flutter in 1, non-AMAT in 14, and focal AT in 1. Recurrence of PMF and RMAT was observed in 15 of 26 (57.7%) and 8 of 18 (44.4%) patients, respectively, while peritricuspid flutter did not recur. Neither the same focal AT nor the same non-AMAT were observed except in 1 case with septal scar–related biatrial AT. Epicardial structure–related ATs were involved in 18 of 24 (75.0%) patients in PMF, 4 of 14 (28.6%) in RMAT, and 4 of 14 (28.6%) in non-AMAT. Of 21 patients with a circuit including epicardial structures, 6 patients treated with ethanol infusion in the vein of Marshall did not show any AT recurrence, although 8 of 15 (53.3%) treated with radiofrequency showed AT recurrence ( P =0.04). Conclusions: Although high-resolution mapping may lead to correct diagnosis and appropriate ablation in the first procedure, the recurrence rate is still high. The main mechanism of atrial fibrillation ablation–related AT is the recurrence of PMF and RMAT or non-AMAT different from the first procedure. Epicardial structures (eg, coronary sinus/vein of Marshall system) are often involved, and ethanol infusion in the vein of Marshall may be an additional treatment.

AIMS We hypothesized that an epicardial approach using ethanol infusion in the vein of Marshall (EIVOM) may improve the result of ablation for perimitral flutter (PMF). METHODS AND RESULTS  We studied 103 consecutive patients with PMF undergoing high-resolution mapping. The first 71 were treated with radiofrequency (RF) ablation alone (RF-group), and the next 32 underwent EIVOM followed by RF on the endocardial and epicardial mitral isthmus (EIVOM/RF-group). Contact force was not measured during ablation. Acute and 1-year outcomes were compared. Flutter termination rates were similar between the RF-group (63/71, 88.7%) and EIVOM/RF-group (31/32, 96.8%, P = 0.27). Atrial tachycardia (AT) terminated with EIVOM alone in 22/32 (68.6%) in the EIVOM/RF-group. Bidirectional block of mitral isthmus was always achieved in the EIVOM/RF-group, but significantly less frequently achieved in the RF-group (62/71, 87.3%; P = 0.05). Median RF duration for AT termination/conversion was shorter [0 (0-6) s in the EIVOM/RF-group than 312 (55-610) s in the RF-group, P < 0.0001], as well as for mitral isthmus block in the EIVOM/RF-group [246 (0-663) s] than in the RF-group [900 (525-1310) s, P < 0.0001]. Pericardial effusion was observed in 1/32 (3.2%) in EIVOM/RF-group and 5/71 (7.0%) in RF-group (P = 0.66); two in RF-group required drainage and one of them developed subsequent ischaemic stroke. One-year follow-up demonstrated fewer recurrences in the EIVOM/RF-group [6/32 (18.8%)] than in the RF-group [29/71 (40.8%), P = 0.04]. By multivariate analysis, only EIVOM was significantly associated with less AT recurrence (hazard ratio = 0.35, P = 0.018). CONCLUSION Ethanol infusion in the vein of Marshall may reduce RF duration required for PMF termination as well as for mitral isthmus block without severe complications, and the mid-term outcome may be improved by this approach.

BACKGROUND Few studies evaluated the impact of catheter ablation (CA) on atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF). OBJECTIVE In the prospective, patient-controlled CLOSE to CURE study, we determined the longer-term impact of optimized CA on ATA burden by using an insertable cardiac monitor (ICM). METHODS A total of 105 patients with paroxysmal AF were implanted with an ICM 65 (interquartile range [IQR] 61-78) days before CA. CA consisted of contact force-guided pulmonary vein isolation targeting an intertag distance of <= 6 mm and a region-specific ablation index. The primary end point was reduction in ICM-detected ATA burden; secondary end points were single-procedure freedom from ATA, quality of life, and adverse events. RESULTS The mean age was 62 6 8 years; the median CHA(2)DS(2)-VASc score was 1 (IQR 1-2); and the median left atrial diameter was 43 (IQR 39-43) mm. After pulmonary vein isolation (1.13 +/- 0.39 procedures per patient), median ATA burden decreased from 2.68% (IQR 0.09%-15.02%) at baseline to 0% (IQR 0%-0%) during the first year and to 0% (IQR 0%-0%) during the second year (reduction in ATA burden 100% [IQR 100%-100%]; P<.001). Single-procedure freedom from any ATA was 87% at 1 year and 78% at 2 years. Quality of life improved significantly across all scores. Adverse events occurred in 5 patients (4.8%). CONCLUSION CA has become an effective procedure in paroxysmal AF, with a major impact on ICM-detected ATA burden. Whereas conventional survival analysis suggests a progressive decline in efficacy, we observed that burden reduction is maintained at longer follow-up. These data imply that ATA burden is a more optimal end point for assessing ablation efficacy.

Background: Atrial fibrillation ablation-related atrial tachycardia (AT) is complex and may demonstrate several forms: anatomic macroreentrant AT (AMAT), non-AMAT, and focal AT. We aimed to elucidate the recurrence rate and mechanisms of atrial fibrillation ablation-related AT recurrence. Methods: Among 147 patients with ATs treated with the Rhythmia system, 68 (46.3%) had recurrence at mean 4.2 (2.9-11.6) months, and 44 patients received a redo procedure. AT circuits in the first procedure were compared with those in the redo procedure. Results: Although mappable ATs were not observed in 7 patients, 68 ATs were observed in 37 patients during the first procedure: perimitral flutter (PMF) in 26 patients, roof-dependent macroreentrant AT (RMAT) in 18, peritricuspid flutter in 10, non-AMAT in 14, and focal AT in 3. During the redo AT ablation procedure, 54 ATs were observed in 41/44 patients: PMF in 24, RMAT in 14, peritricuspid flutter in 1, non-AMAT in 14, and focal AT in 1. Recurrence of PMF and RMAT was observed in 15 of 26 (57.7%) and 8 of 18 (44.4%) patients, respectively, while peritricuspid flutter did not recur. Neither the same focal AT nor the same non-AMAT were observed except in 1 case with septal scar-related biatrial AT. Epicardial structure-related ATs were involved in 18 of 24 (75.0%) patients in PMF, 4 of 14 (28.6%) in RMAT, and 4 of 14 (28.6%) in non-AMAT. Of 21 patients with a circuit including epicardial structures, 6 patients treated with ethanol infusion in the vein of Marshall did not show any AT recurrence, although 8 of 15 (53.3%) treated with radiofrequency showed AT recurrence (P=0.04). Conclusions: Although high-resolution mapping may lead to correct diagnosis and appropriate ablation in the first procedure, the recurrence rate is still high. The main mechanism of atrial fibrillation ablation-related AT is the recurrence of PMF and RMAT or non-AMAT different from the first procedure. Epicardial structures (eg, coronary sinus/vein of Marshall system) are often involved, and ethanol infusion in the vein of Marshall may be an additional treatment.

BACKGROUND The incidence of endoscopically detected esophageal lesions after pulmonary vein isolation (PVI) is as high as 18%. Intraesophageal temperature rise (ITR) during ablation is a predictor of esophageal injury. OBJECTIVE The purpose of this study was to describe an ablation strategy aiming to enclose the pulmonary veins with contiguous, stable, and optimized radiofrequency applications (referred to as CLOSE-PVI). We evaluated esophageal and periesophageal injury with endoscopy in patients revealing ITR during CLOSE-PVI. METHODS Eighty-five patients with ITR during CLOSE-PVI underwent endoscopy of the esophagus (with ultrasound in 38 patients). PVI consisted of contact force (CF)-guided encircling of the veins using 35-W applications, respecting strict criteria of intertag distance (<= 6 mm) and ablation index (AI; 550 arbitrary unit [au] anterior wall, 400 au posterior wall, 300 au if ITR >38.5 degrees C). RESULTS Endoscopy was performed 9 +/- 4 days after PVI. At the posterior wall, median power was 35 W [interquartile range (IQR) 35-35], application time 18 +/- 5 seconds, CF 13 +/- 6g, and AI 403 +/- 38 au. A median of 5 applications [IQR 4-7] per patient over a length of 21.8 +/- 6.8 mm resulted in ITR >38.5 degrees C (median 39.9 degrees C, IQR 39.2 degrees C-41.2 degrees C, range 38.6 degrees C-50.0 degrees C). For these applications, median power was 35 W [IQR 30-35], application time 14 +/- 3 seconds, CF 12 +/- 5g, and AI 351 +/- 38 au. The incidence of esophageal erythema/erosion on endoscopy was 1 of 85 (1.2%) and of ulceration was 0 of 85 (0%). The incidence of mediastinal or esophageal injury on ultrasound was 0 of 38 (0%). CONCLUSION The occurrence of esophageal or periesophageal injury after CLOSE-PVI is markedly low (1.2%). Absence of esophageal ulceration in patients with ITR suggests that this strategy of delivering contiguous, relatively high-power, and short-duration radiofrequency applications at the posterior wall is safe.

BACKGROUND:Atrial fibrillation (AF) is the most common clinical arrhythmia and one of the major causes of stroke, heart failure, sudden death, and cardiovascular morbidity. Despite substantial advances in (interventional) rhythm control treatment during the last decade, anticoagulation for stroke prevention remains a major component of AF treatment.HYPOTHESIS:There are important sex-specific differences in AF-related stroke, resulting from sex-specific mechanisms and therapeutic differences.METHODS:This review summarizes available data on sex differences in risk assessment and prevention of stroke and highlights current knowledge gaps in AF-related stroke mechanisms, prevention and management that warrant further research.RESULTS:Increased thrombotic risk in women is multifactorial, involving hormonal changes after menopause, structural, endocrine and lifestyle/social factors and their interactions. It is clear from randomized studies that women benefit from anticoagulant treatment and that their bleeding risk is similar to men. Women should therefore receive equivalent treatment to men, based on the validated criteria for anticoagulation therapy. However, women are not represented equally in the large randomized studies and sex-related information in many fields is lacking.CONCLUSIONS:Female sex is an established risk factor for stroke in AF patients. The evidence for sex-specific differences in stroke risk assessment and stroke prevention is accumulating. However, the underlying biological mechanisms remain incompletely understood and further studies are required in order to decrease AF-related morbidity and mortality.

BACKGROUND A novel "LUMIPOINT" software in the Rhythmia system (Boston Scientific) displays a histogram of activated area over the entire atrial tachycardia (AT) cycle length (CL) with a normalized score. OBJECTIVE The purpose of this study was to examine whether the pattern of this global activation histogram (GAH) identified reen-trant vs focal AT and whether a decrease in atrial activation area, shown as valleys in the GAH, identifies isthmuses. METHODS One hundred eight activation maps of ATs (17 focal, 57 macroreentrant, 21 localized, 13 multiple loop) in 67 patients were reviewed retrospectively with the LUMIPOINT software. The ACTIVATION SEARCH feature highlighted the activated area in a given time period irrespective of the activation map. A 30-ms unit time interval was set, and the GAH patterns and electrophysiological properties of highlighted areas were examined. RESULTS Focal ATs systematically displayed a plateau with GAH-Score <0.1 for at least 30% of the CL. Most reentrant ATs (90/91 [98.9%]) lacked this plateau and displayed activity covering the entire CL, with 2 [1-2] GAH-Valleys per tachycardia. Each GAH-Valley highlighted 1 [1-2] areas in the map. Among 264 highlighted areas, 198 (75.0%) represented slow conduction, 19 (7.2%) lines of block, 27 (10.2%) wavefront collision, 3 (1.1%) unknown, and 17 (6.4%) absence of activation in focal ATs. Practical ablation sites all matched one of the highlighted areas based on GAH-Valleys, and they corresponded better with areas highlighted by GAH-Score <= 0.2 (P <.0001). CONCLUSION GAH shows focal vs reentrant mechanisms at first glance. Decrease in activated areas (displayed by GAH-Valleys) is mostly due to slow conduction and highlights areas of special interest, with 100% sensitivity for isthmus identification.

OBJECTIVES A new etectroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD). BACKGROUND The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit. METHODS Mapping and ablation data of 61 patients with CHD (35 mates, age 45 +/- 14 years) from 8 tertiary centers were reviewed. RESULTS Causes were as follows: Transposition of Great Arteries (atrial switch) (n = 7); univentricutar physiology (Fontans) (n = 8); Tetralogy of Fattot (n = 10); atrial septat defect (ASD) repair (n = 15); tricuspid valve (TV) anomalies (n = 10); and other (n = 11). The total number of atrial arrhythmias was 86. Circuits were predominantly around the tricuspid valve (n = 37), atriotomy scar (n = 10), or ASD patch (n = 4). Although the majority of peri-tricuspid circuits were cavo-tricuspid-isthmus dependent (n = 30), they could follow a complex route between the annulus and septat resection, ASD patch, coronary sinus, or atriotomy. Immediate ablation success was achieved in all but 2 cases; with follow-up of 12 +/- 8 months, 7 patients had recurrence. CONCLUSIONS We demonstrate the feasibility of the basket catheter for mapping complex CHD arrhythmias, including with transbaffle and transhepatic access. Although the circuits often involve predictable anatomic landmarks, the precise critical isthmus is often difficult to predict empirically. Ultra-high-density mapping enables elucidation of circuits in this complex anatomy and allows successful treatment at the isthmus with a minimal lesion set. (C) 2019 by the American College of Cardiology Foundation.

BACKGROUND Wall thickness (WT) in post-myocardial infarction scar is heterogenous, with channels of relatively preserved thickness bordered by thinner scar. OBJECTIVE This study sought to determine whether 3-dimensionallyreconstructed computed tomography (CT) channels correlate with electrophysiological isthmuses during ventricular tachycardia (VT). METHODS We retrospectively studied 9 postinfarction patients (aged 57 +/- 15 years, 1 female) with 10 complete VT activation maps (cycle length 429 +/- 77ms) created using high-resolution mapping. Three-dimensionally-reconstructed WT maps from CT were merged with the activation map during sinus rhythm (SR) and VT. The relationship between WT and electrophysiological characteristics was analyzed. RESULTS A total of 41 CT channels were identified (median 4 per patient), of median (range) length 21.2 mm (17.3-36.8 mm), width 9.0 mm (6.7-16.5 mm), and area 1.49 cm(2) (1.00-1.75 cm(2)). WT in the channel was significantly thicker in the center than in the edge (median 2.4 mm vs 1.5 mm, P < .0001). Of 3163 (2493-5960) mapping points in SR, 382 (191-1115) local abnormal ventricular activities (LAVAs) were identified. One patient had a maximal proportion of LAVAs in 3-4 mm, 3 patients in 2-3 mm, 2 in 1-2 mm, and 2 in 0-1 mm. The VT isthmuses of all 10 VTs corresponded with 1-4 CT channels. Twenty-one of the 41 CT channels (51.2%) corresponded to a VT isthmus (entrance, mid, or exit). Electrophysiological VT isthmuses were more likely to be associated with CT channels that were longer (P = .04, odds ratio [OR] 1.05/mm), thinner (but not less than 1 mm) (P = .03, OR 0.36/mm), or parallel to the mitral annulus (P = .07, OR 3.93). CONCLUSION VT isthmuses were always found in CT channels (100% sensitivity), and half of CT channels hosted VT isthmuses (positive predictive value 51%). Longer and thinner (but >1 mm) CT channels were significantly associated with VT isthmuses.

BACKGROUND:Pulmonary vein isolation (PVI) modulates the intrinsic cardiac autonomic nervous system (ANS). We evaluated the impact of PVI on 5 non-invasive autonomic tests. METHODS:Thirty patients (76% male, mean age 60.37 ± 9.02 years) with paroxysmal atrial fibrillation (AF) underwent cryoballoon-guided PVI. Five autonomic tests were performed 24hrs before and after PVI (N = 30) and repeated after 6months (N = 22). Parasympathetic function was measured by heart rate (HR) variability during deep breathing (E/I ratio, I-E difference), Valsalva maneuver (Valsalva-ratio) and head-up tilt test (30/15 ratio). Sympathetic function was measured by systolic BP response to sustained handgrip and 10' tilting and by diastolic BP response to cold water. RESULTS:24hrs after PVI, baseline HR increased from 57.93 ± 9.06 bpm to 71.10 ± 12.75 bpm (p < 0.001). At 6 months, baseline HR was lower than immediately post-PVI (62.59 ± 7.89 vs 71.36 ± 13.58 bpm, p = 0.032) but still higher in comparison to pre-PVI (62.59 ± 7.89 vs 57.09 ± 8.80 bpm, p < 0.001). No differences were seen in baseline BP and parasympathetic tests acutely and at 6months. Besides an acute lowering in systolic BP increase during handgrip test, all sympathetic tests remained unchanged. CONCLUSIONS:An acute HR increase attenuated at 6months and an acute lowered systolic BP response to sustained handgrip were the only changes after cryoballoon-guided PVI. Non-invasive autonomic tests seem therefore not appropriate to evaluate the autonomic modulatory effect of PVI, either due to a too limited sensitivity or a too localized effect of PVI to influence test results.