Extra Mapping Research Articles

New mapping for determination of left atrial posterior wall isolation for non-paroxysmal atrial fibrillation

Abstract Background Recent studies have reported that the efficacy of posterior wall isolation(PWI) created by cryoballoon for non-paroxysmal atrial fibrillation. However, there are no clear criteria for determining whether or not to perform PWI, and it is left to the discretion of the operator. Then we evaluated the necessity of additional PWI by measuring non-passively activated ratios(%NP), the ratio of the form of rotors and multiple wavelets, using ExTRa mapping and verified its usefulness. Methods and Results 44 patients with non-paroxysmal atrial fibrillation who underwent cryoballoon ablation(CBA) were divided into two groups according to whether using ExTRa mapping(ExTRa group; 21 patients) or not(no-ExTRa group; 23 patients), and the long-term results were compared. In ExTRa group, ExTRa mapping was performed before PVI, after PVI, and after roof block(LA-RB) creation using cryoballoon. After creating LA-RB, if more than 50% of %NP remained in the left atrium, PWI was performed by creating a bottom block(LA-BB) using cryoballoon. After a median follow-up period of 12months(2 to 34 months), arrhythmia-free survival rate was higher in the ExTRa group than in the no-ExTRa group(95.2% vs 69.6%, p<0.05%). Conclusion Evaluation of %NP using ExTRa mapping is extremely useful in determining the additional PWI for non-paroxysmal atrial fibrillation.Voltage mapping & ExTRa mapping

Atrial fibrillation activation patterns predict freedom from arrhythmias after catheter ablation: utility of ExTRa mapping™.

Mechanisms underlying atrial fibrillation (AF) are widely complex and vary tremendously among individuals. This retrospective study aimed to investigate the association between AF activation patterns and clinical outcomes post-ablation. Fifty-five AF patients (64.0 ± 12.9 years; 41 men; 17 paroxysmal) underwent bi-atrial endocardial driver mapping during AF pre-ablation with a real-time phase mapping system (ExTRa Mapping). The nonpassively activated ratio (%NP) of meandering rotors and multiple wavelets relative to the recording time was evaluated in 26 atrial segments [15 in the left atrium (LA) and 11 in the right atrium]. Irrespective of the mapping results, all patients underwent standard AF ablation via cryoballoons and/or radiofrequency catheters. In a median follow-up interval of 27(14-30) months, 69.1% of patients were free from recurrent arrhythmias and antiarrhythmic drugs at one year post-procedure. Patients with recurrent AF were more likely to have non-paroxysmal AF, a significantly larger LA size, and higher LA maximal %NP(LAmax%NP) and LA anterior wall %NP(LAAW%NP) than those without recurrent AF. A multivariate Cox regression analysis showed that both an LAmax%NP (hazard ratio [HR] = 1.075; 95% confidence interval [CI] = 1.02-1.14, p = 0.012) and LAAW%NP (HR = 1.061; 95% CI = 1.01-1.11, p = 0.013) were independent predictors of atrial arrhythmia recurrence. The optimal cutoff points for the LAmax%NP and LAAW%NP for predicting AF recurrence were 64.5% and 60.0%, respectively. A Kaplan-Meier analysis demonstrated that both an LAmax%NP > 64.5% (p = 0.0062) and LAAW%NP > 60.0% (p = 0.014) were associated with more frequent AF recurrences. Baseline AF activation pattern mapping may aid in predicting freedom from arrhythmias after standard AF ablation procedures.

Association with the nonparoxysmal atrial fibrillation duration and outcome of ExTRa Mapping-guided rotor ablation.

Additional ablation strategies after pulmonary vein isolation (PVI) for patients with nonparoxysmal atrial fibrillation (non-PAF) lasting ≥2 years have not been fully effective. This is presumably because of insufficient identification of non-PAF maintenance mechanisms. In this study, we employed a novel online and real-time phase mapping system, ExTRa Mapping, to identify and modulate rotors as one of the non-PAF maintenance mechanisms in patients with non-PAF sustained after PVI. We investigated the relationship between outcomes of ExTRa Mapping-guided rotor ablation (ExTRa-ABL) and non-PAF duration prior to this procedure. This study consisted of 73 non-PAF patients (63 ± 8 years, non-PAF duration 31 ± 37 months) who underwent the first ExTRa-ABL in patients with non-PAF sustained after completion of PVI. Freedom from non-PAF/atrial tachycardia (AT) recurrence at 12 months after ExTRa-ABL was achieved in 50 (69%) of patients. The non-PAF duration prior to ExTRa-ABL was significantly longer in patients with non-PAF/AT recurrence after ExTRa-ABL compared with those without (56 ± 50 vs. 19 ± 22 months, p = .001). In patients with non-PAF duration of ≤60 months prior to ExTRa-ABL, compared with >60 months, non-PAF/AT-free rate was significantly higher (68.9% vs. 23.1%, p < .001), during the follow-up of 36 ± 18 months. A non-PAF duration of ≤60 months prior to ExTRa-ABL was associated with a better outcome. The effect of ExTRa-ABL was considered to be limited in patients with >60 months of non-PAF duration.

The safety and efficacy of rotor ablation in right atrium after pulmonary vein isolation in patients with persistent atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background Phase mapping using software of ExTRa Mapping is a new tool to clarify the localization of rotor in atrial fibrillation (AF), but the spatial distribution of rotor in right atrium (RA) and the effect of ablation is not clear compared with left atrium (LA). Purpose This study sought to investigate the spatial distribution of rotor in RA and the safety and effectiveness of RA rotor ablation after pulmonary vein isolation (PVI) in patients with persistent AF. Methods ExTRa mapping with a 20-polar Reflexion catheter in RA was performed in 2nd or 3rd ablation for recurrent AF after PVI in 16 patients with persistent AF (including 4 patients with long standing &amp;gt;1 year AF, 15 men, mean age 67±7.7years old, mean LAD 42±5.4mm, mean EF 57±11%). Rotor was defined as NPAs (non-passively activated areas) in which the percentage of the non-passively activated period in the recording time of 5 seconds is over 50%. RA was divided into 5 areas of crista terminalis (CT), septum (Sept), free wall of RA appendage (fRAA), septal side of RAA (sRAA), behind aorta (Ao), and distribution of NPAs was investigated. RA minimal ablation to NPAs was performed to avoid sinus node and phrenic nerve. The outcomes of AF recurrence were analyzed. Results NPAs in RA were observed in 15 of 16 cases, and 67% of cases in CT, 75% in Sept, 80% in fRAA, 20% in sRAA, and 43% in Ao. RA minimal ablation was performed in 21 NPAs in 8 patients to avoid sinus node and phrenic nerve. In a mean follow-up of 307±204 days, freedom from any atrial tachyarrhythmias without antiarrhythmic drugs was achieved in 9 of 16 patients (56%). In 4 (80%) of 5 patients in whom more than 75% area of NPAs were eliminated, sinus rhythm was maintained. There was no serious complication. Conclusion Rotor in RA existed relatively frequently in septum, fRAA and CT. RA rotor ablation was safe and could be a new strategy after PVI for persistent AF.

Effect of pulmonary vein isolation on rotor/multiple wavelet dynamics in persistent atrial fibrillation, association with vagal response and implications for adjunctive ablation

Persistent atrial fibrillation (PeAF) may develop arrhythmogenic substrates of rotors/multiple wavelets. However, the ways in which pulmonary vein isolation (PVI) affects the dynamics of rotor/multiple wavelets in PeAF patients remain elusive. Real-time phase-mapping (ExTRa mapping, EXT) in the whole left atrium (LA) was performed during PeAF before and after PVI (n = 111). The percentage of time in which rotor/multiple wavelets (phase singularities) was observed during each 5-s phase-mapping recording (non-passive activation ratio, %NP) was measured as an index of its burden. The mapping areas showing %NP ≥ 50% were defined as rotor/multiple-wavelet substrates (RSs). Before PVI, RSs were globally distributed in the LA. After PVI, %NP decreased (< 50%) in many RSs (PVI-modifiable RSs) but remained high (≥ 50%) in some RSs, especially localized in the anterior/septum/inferior regions (PVI-unmodifiable RSs, 2.3 ± 1.0 areas/patient). Before PVI, vagal response (VR) to high-frequency stimulation was observed in 23% of RSs, especially localized in the inferior region. VR disappearance after PVI was more frequently observed in PVI-modifiable RSs (79%) than in PVI-unmodifiable RSs (55%, p < 0.05), suggesting that PVI affects autonomic nerve activities and rotor/multiple wavelet dynamics. PVI-unmodifiable RSs were adjunctively ablated in 104 patients. The 1-year AT/AF-free survival rate was 70% in those with PVI alone (n = 115), and 86% in patients with the adjunctive ablation (log-rank test = 7.65, p < 0.01). PVI suppresses not only ectopic firing but also rotor/multiple wavelets partly via modification of autonomic nerve activities. The adjunctive ablation of PVI-unmodifiable RSs improved the outcome in PeAF patients and might be a novel ablation strategy beyond PVI.

Abstract 14823: Atrial Electrical Substrates Associated With Atrial Fibrillation Drivers Analyzed With Real-Time Phase Mapping “ExTRa Mapping” in Patients With Persistent Atrial Fibrillation

Introduction: Elucidation of the mechanism of atrial fibrillation (AF) will lead to improved catheter ablation outcomes. However, the electrical substrates on which AF drivers such as meandering rotors and multiple wavelets are likely to appear are still unclear. Methods: Twenty-nine patients (age 68±10 years, eight females) with persistent AF were included in this study. Real-time phase mapping (ExTRa mapping) was performed in the left atrium during AF. After that, electroanatomical mapping such as voltage and activation mapping with HD-grid catheter was performed after conversion to sinus rhythm with cardioversion. According to the nonpassively activated ratio (%NP: the ratio of the form of rotors and/or multiple wavelets to the recording time), the recorded three highest %NP (Active-area) and three lowest %NP areas (Passive-area) were collected in each subject. Electrical property and overlapping with the low-voltage zone (LVZ, voltage amplitude &lt;0.5mV) or mid-voltage zone (MVZ, 0.5-1.0mV) within these areas were assessed and compared between the Active- and the Passive-areas. Results: We analyzed a total of 87 Active- and 84 Passive-areas and the mean %NP were 61±8% and 13±8%, respectively. Signals with ≥4 fractionated components (fractionated electrograms) were seen significantly more in the Active-areas than in the Passive-areas (53% vs. 26%, respectively; p&lt;0.001, Figure A ). However, there was no difference in the conduction velocity (0.70±0.34m/s vs. 0.73±0.30m/s; p=0.577), mean voltage amplitude (1.78±1.54mV vs. 1.71±1.53mV; p=0.794) and coinciding with LVA/MVA (43% vs. 41%; p=0.785) between the Active- and the Passive-areas ( Figure B-D ). Conclusion: AF drivers tended to appear in the area with fractionated electrograms. High %NP areas partly overlapped, but not always coincided with LVA/MVA, as much as low %NP areas.

Instability of rotational activation as atrial fibrillation drivers: Assessment by ExTRa Mapping system.

ExTRa Mapping™ has developed to visualize rotational activation as atrial fibrillation (AF) drivers. The current study was sought to evaluate the instability of AF drivers by ExTRa Mapping™. Variation of nonpassively activated ratio (%NP) among three-time repetitive recordings before and after pulmonary vein isolation (PVI) in left atrium was assessed in 26 persistent AF patients. The recoding time was set at 5 or 8 s for the respective patients. The outcome measures included %NP at each recording, mean value of the three-time recordings, and the instability index, which was defined as maximum difference per mean %NP × 100 (%). Total 683 sites 2049 recordings were assessed. Mean %NP was 33.3(23.3-42.7)%, and higher in sites with severe (≥50%) and patchy low voltage area than those without, but not in those with severe complex fractionated atrial electrogram area. There was significant correlation between actual and mean %NP (R=0.86, P< .001), but maximum difference among the repetitive recordings was 16(10-24)%. The instability index of %NP was 55.9(30.9-83.6)%, and significantly lower at the recordings of 8s compared with 5s (50.6[28.6-78.4]% vs. 60.4[35.0-90.0]%, P=.004). Furthermore, it was higher at sites with lower reliability of the recordings. After PVI, mean %NP significantly decreased (28.7[18.3-36.7]% vs. 37.7[28.7-45.7]%, P<.001), but the instability index significantly increased compared with those before PVI (60.0[35.0-92.7]% vs. 48.9[29.1-75.0]%, P=.001). Rotational activation as AF drivers assessed by ExTRa Mapping™ is unstable, and repetitive and longer recording is required for the reliable assessment even after PVI.

The impact of the atrial wall thickness in normal/mild late-gadolinium enhancement areas on atrial fibrillation rotors in persistent atrial fibrillation patients.

BackgroundSome of atrial fibrillation (AF) drivers are found in normal/mild late‐gadolinium enhancement (LGE) areas, as well as moderate ones. The atrial wall thickness (AWT) has been reported to be important as a possible AF substrate. However, the AWT and degree of LGEs as an AF substrate has not been fully validated in humans.ObjectiveThe purpose of this study was to evaluate the impact of the AWT in normal/mild LGE areas on AF drivers.MethodsA total of 287 segments in 15 persistent AF patients were assessed. AF drivers were defined as non‐passively activated areas (NPAs), where rotational activation was frequently observed, and were detected by the novel real‐time phase mapping (ExTRa Mapping), mild LGE areas were defined as areas with a volume ratio of the enhancement voxel of 0% to <10%. The AWT was defined as the minimum distance from the manually determined endocardium to the epicardial border on the LGE‐MRI.ResultsNPAs were found in 20 (18.0%) of 131 normal/mild LGE areas where AWT was significantly thicker than that in the passively activated areas (PAs) (2.5 ± 0.3 vs. 2.2 ± 0.3 mm, p < .001). However, NPAs were found in 41 (26.3%) of 156 moderate LGE areas where AWT was thinner than that of PAs (2.1 ± 0.2 mm vs. 2.23 ± 0.3 mm, p = .02). An ROC curve analysis yielded an optimal cutoff value of 2.2 mm for predicting the presence of an NPA in normal/mild LGE areas.ConclusionThe location of AF drivers in normal/mild LGE areas might be more accurately identified by evaluating AWT.

Late-gadolinium enhancement properties associated with atrial fibrillation rotors in patients with persistent atrial fibrillation.

A computational model demonstrated that atrial fibrillation (AF) rotors could be distributed in patchy late-gadolinium enhancement (LGE) areas and play an important role in AF drivers. However, this was not validated in humans. The purpose of this study was to evaluate the LGE properties of AF rotors in patients with persistent AF. A total of 287 segments in 15 patients with persistent AF (long-standing persistent AF in 9 patients) that underwent AF ablation were assessed. Non-passively activated areas (NPAs), where rotational activation (AF rotor) was frequently observed, were detected by the novel real-time phase mapping (ExTRa Mapping). The properties of the LGE areas were assessed using the LGE heterogeneity and the density which was evaluated by the entropy (LGE-entropy) and the volume ratio of the enhancement voxel (LGE-volume ratio), respectively. NPAs were found in 61 (21%) of 287 segments and were mostly found around the pulmonary vein antrum. A receiver operating characteristic curve analysis yielded an optimal cutoff value of 5.7% and 10% for the LGE-entropy and LGE-volume ratio, respectively. The incidence of NPAs was significantly higher at segments with an LGE-entropy of >5.7 and LGE-volume ratio of >10% than at the other segments (38 [30%] of 126 vs. 23 [14%] of 161 segments; p = .001). No NPAs were found at segments with an LGE-volume ratio of >50% regardless of the LGE-entropy. Of five patients with AF recurrence, NPAs outside the PV antrum were not ablated in three patients and the remaining NPAs were ablated, but their LGE-entropy and LGE-volume ratio were low. AF rotors are mostly distributed in relatively weak and much more heterogenous LGE areas.

MRSaiFE: An AI-based Approach Towards the Real-Time Prediction of Specific Absorption Rate.

The purpose of this study is to investigate feasibility of estimating the specific absorption rate (SAR) in MRI in real time. To this goal, SAR maps are predicted from 3T- and 7T-simulated magnetic resonance (MR) images in 10 realistic human body models via a convolutional neural network. Two-dimensional (2-D) U-Net architectures with varying contraction layers and different convolutional filters were designed to estimate the SAR distribution in realistic body models. Sim4Life (ZMT, Switzerland) was used to create simulated anatomical images and SAR maps at 3T and 7T imaging frequencies for Duke, Ella, Charlie, and Pregnant Women (at 3, 7, and 9 month gestational stages) body models. Mean squared error (MSE) was used as the cost function and the structural similarity index (SSIM) was reported. A 2-D U-Net with 4 contracting (and 4 expanding) layers and 64 convolutional filters at the initial stage showed the best compromise to estimate SAR distributions. Adam optimizer outperformed stochastic gradient descent (SGD) for all cases with an average SSIM of 90.5∓3.6 % and an average MSE of 0.7∓0.6% for head images at 7T, and an SSIM of >85.1∓6.2 % and an MSE of 0.4∓0.4% for 3T body imaging. Algorithms estimated the SAR maps for 224×224 slices under 30 ms. The proposed methodology shows promise to predict real-time SAR in clinical imaging settings without using extra mapping techniques or patient-specific calibrations.

Abstract 15553: The Long-term Outcome Beyond Pulmonary Vein Isolation of Ablation Guided by the Online and Real-time Atrial Fibrillation Imaging System: Extra Mapping Project

Introduction: Although modulation of atrial fibrillation (AF) drivers and/or substrates has been proposed as one of the effective ablation strategies for non-paroxysmal AF (Non-PAF), previous meta-analyses showed that ablation, targeting complex fractionated atrial electrogram (CFAE) indirectly-reflecting Non-PAF drivers, had no additional benefit for post-pulmonary vein isolation (PVI) Non-PAF. As an alternative ablation strategy for Non-PAF, rotor ablation has been proposed as one of the potentiated ablation strategies for Non-PAF. However, the optimal ablation strategy is still unclear because reliable method detecting AF drivers remain unsettled in clinical practice. Hypothesis: Because rotors are known as key mechanisms for Non-PAF, we might open the possibility of Non-PAF control by the real-time visualization of wave dynamics during AF ablation. Methods: Consecutive 140 Non-PAF patients were enrolled in this study. The clinically-available online and real-time AF imaging system with high-spatiotemporal density (ExTRa Mapping TM ) developed by our group was applied in case Non-PAF was remained after PVI. Then, we detected and ablated non-passively-activated areas where rotational activations in the form of meandering rotors and/or multiple wavelets assumed to contain Non-PAF drivers were frequently observed (figure, top). The recurrence rate of Non-PAF or atrial tachycardia (AT) after the ablation was compared to that in patients underwent PVI-alone at our hospital. Results: The propensity scores selected each 34 people from ExTRa-strategy group and PVI-alone group (figure, middle). The 24-month freedom ratio from Non-PAF/AT in the matched-ExTRa-strategy group was higher than the matched-PVI-alone group, which was close to significance (p = 0.056) (figure, bottom). Conclusion: The ExTRa Mapping-guided ablation for PVI-refractory Non-PAF might be superior to PVI-alone.

Impact of Box Isolation on Rotors and Multiple Wavelets in Persistent Atrial Fibrillation.

Additional benefits of posterior left atrial (LA) box isolation (BOXI) over pulmonary vein isolation (PVI) in persistent atrial fibrillation (perAF) have been reported, but the mechanism is still unclear. We evaluated the effects of BOXI on rotors and multiple wavelets in the whole LA.Methods and Results:Twenty patients with perAF (including 12 cases of longstanding perAF) underwent PVI. Real-time phase mapping (ExTRa Mapping) was performed in the whole LA during AF. Subsequently, BOXI was added and re-ExTRa Mapping was performed again at the same site. The nonpassively activated ratio (%NP), the ratio of the form of rotors and multiple wavelets to the recording time, was compared before and after BOXI. After BOXI, the %NP significantly decreased in the anterior wall (from 53±22% to 39±23%, P=0.010), inferior wall (from 51±16% to 34±19%, P=0.001), and LA appendage (from 23±27% to 16±19%, P=0.049). However, there were no significant differences in the septum (49±19% vs. 49±18%, P=0.562) or lateral wall (41±19% vs. 38±15%, P=0.526). BOXI not only reduced the critical mass for maintenance of AF, but also decreased the rotors and multiple wavelets in the anterior wall, inferior wall and LA appendage during perAF.

A mapping-function-free WENO-M scheme with low computational cost

The classical WENO-JS scheme developed by Jiang and Shu [5] suffers accuracy loss near a critical point in smooth region. An extra mapping process was introduced by Henrick et al. [6] to overcome this problem with significantly increased computational cost, known as WENO-M scheme. In order to reduce the cost brought by the mapping process, a pre-discrete mapping method is proposed in this article. The cost of this new method is not only low, but also independent of the complexity of mapping function. Numerical experiments with one- and two- dimensional benchmark problems are conducted to demonstrate the effectiveness of this new method. Compared to the original method, the cost is reduced by 52%.

P4764Relationship of the duration of pulmonary vein isolation-refractory non-paroxysmal atrial fibrillation to the middle- to long-term outcome of the ExTRa Mapping-guided ablation

Abstract Introduction It is reported that for patients with non-paroxysmal (persistent or long-standing persistent) atrial fibrillation (Non-PAF), extended ablation to atrial walls in addition to pulmonary vein isolation (PVI) did not improve the long-term outcome. On the other hand, modulation of Non-PAF drivers (or perpetuators) has been proposed as one of the alternative effective ablation strategies for Non-PAF. Purpose To clarify whether the rotor ablation under online real-time high-density phase mapping system is effective for PVI-refractory Non-PAF ablation. Methods Under such circumstances, our academic group had recently developed the online real-time high-density phase mapping system (ExTRa Mapping™) by industrial alliance. The phase map moving images were based on 41 intra-atrial bipolar signals recorded by a 20-pole spiral-shaped catheter (2.5 cm in diameter) and on in silicorapid prediction of spatio-temporal atrial excitations (artificial intelligence system). Then we applied the ExTRa Mapping to clinical practice in order to directly visualize rotors in patients with Non-PAF, and investigated the middle- to long-term outcome of the ExTRa Mapping-guided rotor ablation (ExTRa-ABL). Results Thirty-eight patients (63±8 y/o, 30 males) with Non-PAF demonstrating refractoriness to PVI were enrolled in this study. Ablation for cavo-tricuspid isthmus and/or superior vena cava isolation was additionally performed at physicians' discretion. After these procedures, the ExTRa-ABL was performed in order to modify Non-PAF substrates, causing rotor control. The modification of the rotors was evaluated by re-mapping with the use of the ExTRa Mapping at the end of each ablation session. Patients were followed at 1, 3, 6 months and every year after the procedure. All of them were followed for 21±8 months. During the follow-up period, Non-PAF was recurred in only 8 of 38 (21%). Furthermore, we found if PVI-refractory Non-PAF duration was shorter than 6 years, the non-recurrence rate remained ≥80% (see Figure), which was markedly better outcome comparing with previous reports with regard to Non-PAF ablation. Figure 1 Conclusion Comparing with conventional Non-PAF ablation strategies, our novel approach with the use of the online real-time high-density phase mapping system might improve medium- to long-term outcome of PVI-refractory Non-PAF treatment.

Not all rotors, effective ablation targets for nonparoxysmal atrial fibrillation, are included in areas suggested by conventional indirect indicators of atrial fibrillation drivers: ExTRa Mapping project.

BackgroundEffects of nonparoxysmal atrial fibrillation (non‐PAF) ablation targeting complex fractionated atrial electrogram (CFAE) areas and/or low voltage areas (LVAs) are still controversial.Methods and ResultsA recently developed online real‐time phase mapping system (ExTRa Mapping) was used to conduct LVA mapping and simultaneous ExTRa and CFAE mapping in 28 non‐PAF patients after pulmonary vein isolation (PVI). Nonpassively activated areas, in the form of meandering rotors and/or multiple wavelets assumed to contain non‐PAF drivers, partly overlapped with CFAE/LVAs but not always coincided with them.ConclusionReal‐time rotor imaging, rather than conventional indirect indicators only, might be very useful for detecting non‐PAF drivers.

Mechanisms of non-paroxysmal atrial fibrillation persistency uncovered by the ExTRa Mapping

Mechanisms of non-paroxysmal atrial fibrillation persistency uncovered by the ExTRa Mapping

非発作性心房細動に対するExTRa Mappingガイド下アブレーションの有用性：ExTRa Mapping Project

非発作性心房細動に対するExTRa Mappingガイド下アブレーションの有用性：ExTRa Mapping Project

P1718Non-paroxysmal atrial fibrillation wave dynamics were determined by age rather than echocardiographic measurements and BNP: A clinical study using the ExTRa Mapping system

P1718Non-paroxysmal atrial fibrillation wave dynamics were determined by age rather than echocardiographic measurements and BNP: A clinical study using the ExTRa Mapping system

P2649Not all non-paroxysmal atrial fibrillation drivers are included in complex fractionated electrogram area or low-voltage area: ExTRa Mapping project

P2649Not all non-paroxysmal atrial fibrillation drivers are included in complex fractionated electrogram area or low-voltage area: ExTRa Mapping project

慢性心房細動アブレーションに向けたオンラインリアルタイム位相マッピングの意義：ExTRa Mapping研究

慢性心房細動アブレーションに向けたオンラインリアルタイム位相マッピングの意義：ExTRa Mapping研究