Early atrial fibrillation recurrence post catheter ablation: Analysis from insertable cardiac monitor in the era of optimized radiofrequency ablation

BACKGROUND

Early recurrence of atrial tachyarrhythmia (ERAT) is associated with ablation-induced proarrhythmogenic inflammation; however, existing studies used intermittent monitoring or nonoptimized radiofrequency (RF) applications (noncontiguous or without ablation index target value).

OBJECTIVE

The purpose of this study was to investigate the relationship between ERAT and late recurrence based on insertable cardiac monitor (ICM) data.

METHODS

We compiled data from Close-To-Cure and Close Maze studies, which enrolled patients who underwent RF ablation for paroxysmal or persistent atrial fibrillation (AF). All patients were implanted with an ICM 2-3 months before ablation.

RESULTS

We studied 165 patients (104 with paroxysmal AF, 61 with persistent AF). Over the 1-year follow-up period, 41 of the patients experienced late recurrence. The risk of late recurrence was higher in patients experiencing ERAT (hazard ratio [HR] 6.2; 95% confidence interval [CI] 3.0-13.0), with negative and positive predictive values of 90.5% and 45.7%, respectively. Median burden of AF during the blanking period was significantly higher in patients with late recurrence (7.9% [0.0%-99.6%]) compared to those without recurrence (0.0% [0.0%-6.0]; P <.001). For each 1% increase in AF burden during the blanking period, late recurrence increased by 4.6% (HR 1.046; 95% CI 1.035-1.059). The best tradeoff for predicting AF from ERAT occurrence was AF burden of 0.6% and last ERAT at 64 days.

CONCLUSION

In patients ablated for paroxysmal and persistent AF with a durable RF lesion set and implanted with a continuous monitoring device, postablation early AF recurrence and burden significantly predict late recurrence. The post-AF ablation blanking period should be reduced to 2 months.

Validation of a Machine Learning Algorithm to Identify Pulmonary Vein Isolation during Ablation Procedures for the Treatment of Atrial Fibrillation: Results of the PVISION Study

BACKGROUND AND AIMS

Pulmonary Vein Isolation (PVI) is the cornerstone of ablation for atrial fibrillation. Confirmation of PVI can be challenging due to far field electrograms and sometimes requires additional pacing maneuvers or mapping. This prospective multicenter study assessed the agreement between a previously trained automated algorithm designed to determine vein isolation status with expert opinion in real-world clinical setting.

METHOD

Consecutive patients scheduled for PVI were recruited at four centers. The ECGenius electrophysiology recording system (CathVision ApS, Denmark) was connected in parallel with the lab's existing system. Electrograms from a circular mapping catheter were annotated during sinus rhythm at baseline pre-ablation, time of isolation, and post-ablation. The ground truth for isolation status was based on operator opinion. The algorithm was applied to the collected PV signals off-line and compared to expert opinion. The primary endpoint was a sensitivity and specificity exceeding 80%.

RESULTS

Overall, 498 electrograms (248 at baseline and 250 at PVI) with 5,473 individual PV beats from 89 patients (32 females, 62 ±12 years) were analyzed. The algorithm performance reached an area under curve (AUC) of 92% and met the primary study endpoint with a sensitivity and specificity of 86% and 87%, respectively (p = 0.005; p = 0.004). The algorithm had an accuracy of 87% in classifying the time of isolation.

CONCLUSION

This study validated an automated algorithm using machine learning (ML) to assess the isolation status of pulmonary veins in patients undergoing PVI with different ablation modalities. The algorithm reached an AUC of 92% with both sensitivity and specificity exceeding the primary study endpoints.

Procedural performance and outcome after pulsed field ablation for pulmonary vein isolation: comparison with a reference radiofrequency database

Aims

Pulsed field ablation (PFA) is a promising ablation technique for pulmonary vein isolation (PVI) with appealing advantages over radiofrequency (RF) including speed, tissue selectivity, and the promise of enhanced durability. In this study, we determine the procedural performance, efficacy, safety, and durability of PFA and compare its performance with a dataset of optimized RF ablation.

Methods and results

After propensity score matching, we compared 161 patients who received optimized RF-guided PVI in the PowerPlus study (CLOSE protocol) with 161 patients undergoing PFA-guided PVI for paroxysmal or persistent atrial fibrillation (AF; pentaspline basket catheter). The median age was 65 years with 78% paroxysmal AF in the PFA group (comparable characteristics in the RF group). Pulsed field ablation-guided PVI was obtained in all patients with a procedure time of 47 min (vs. 71 min in RF, P < 0.0001) and a fluoroscopy time of 15 min (vs. 11 min in RF, P < 0.0001). One serious adverse event [transient ischaemic attack] occurred in a patient with thrombocytosis (0.6 vs. 0% in RF). During the 6-month follow-up, 24 and 27 patients experienced a recurrence with 20 and 11 repeat procedures in the PFA and the RF groups, respectively (P = 0.6 and 0.09). High-density mapping revealed a status of 4 isolated veins in 7/20 patients in the PFA group and in 2/11 patients in the RF group (35 vs. 18%, P = 0.3).

Conclusion

Pulsed field ablation fulfils the promise of offering a short and safe PVI procedure, even when compared with optimized RF in experienced hands. Pulmonary vein reconnection is the dominant cause of recurrence and tempers the expectation of a high durability rate with PFA.

Evaluation of a standardized approach using optimized and contiguous RF applications for electrical isolation of the superior vena cava

The superior vena cava (SVC) is well described as one of the most common non-pulmonary vein (PV)-triggers for atrial tachyarrhythmias (ATA). In our study we evaluated a standardized approach for electrical isolation of the SVC from the right atrium using a horseshoe-shaped lesion set with optimized and contiguous ostial RF lesions. The results are promising, demonstrating a very high rate of acute SVC isolation in a safe and time efficient manner (mostly less than 10 min).

Long-term clinical outcome of atrial fibrillation ablation in patients with history of mitral valve surgery

Aims

Atrial fibrillation (AF) occurs frequently after mitral valve (MV) surgery. This study aims to evaluate the efficacy and long-term clinical outcomes after the first AF ablation in patients with prior MV surgery.

Methods

Sixty consecutive patients with a history of MV surgery without MAZE referred to three European centers for a first AF ablation between 2007 and 2017 (group 1) were retrospectively enrolled. They were matched (propensity score match) with 60 patients referred for AF ablation without prior MV surgery (group 2).

Results

After the index ablation, 19 patients (31.7%) from group 1 and 24 (40%) from group 2 had no recurrence of atrial arrhythmias (ATa) (p = 0.3). After 62 (48-84) months of follow-up and 2 (2-2) procedures, 90.0% of group 1 and 95.0% of group 2 patients were in sinus rhythm (p = 0.49). In group 1, 19 (31.7%) patients had mitral stenosis, and 41 (68.3%) had mitral regurgitation. Twenty-seven (45.0%) patients underwent mechanical valve replacement and 33 (55.0%) MV annuloplasty. At the final follow-up, 28 (46.7%) and 33 (55.0%) patients were off antiarrhythmic drugs (p = 0.46). ATa recurrence was seen more commonly in patients with prior MV surgery (54 vs. 22%, respectively, p < 0.05). No major complication occurred.

Conclusion

Long-term freedom of atrial arrhythmias after atrial fibrillation catheter ablation is achievable and safe in patients with a history of mitral valve surgery. In AF patients without a history of mitral valve surgery, repeated procedures are needed to maintain sinus rhythm.

Clinical validation of an artificial intelligence algorithm offering cross-platform detection of atrial fibrillation using smart device electrocardiograms

Introduction

Multiple smart devices capable of “screening” for atrial fibrillation (AF) based on single-lead electrocardiogram (SL ECG) are presently available. Manufacturers' algorithm capabilities and accuracy for the automated detection of AF vary. Reliable artificial intelligence (AI) algorithms would be valuable to assist physicians with managing the large amount of data. We aimed to assess the clinical value of applying a smart device agnostic AI-based algorithm for the detection of AF from five different smart devices (four smartwatches, one handheld device) and compared the results to the cardiologist-interpreted 12-lead ECG in a real world cohort of patients.

Methods

This is a prospective, observational study enrolling patients presenting to a cardiology service at a tertiary referral center. Patients were prescribed a 12-lead ECG, followed by five consecutive smart device recordings from five different manufacturers. SL ECGs were exported as PDF files from the devices and analyzed by a deep neural network (DNN) based platform which allows automated AI assisted cardiac rhythm interpretation.

Results

We prospectively enrolled 157 patients (32% female, median age 66 years). AF was present in 48 patients (31%) at time of recording, as documented by the 12-lead ECG. Accuracy for the detection of AF by the DNN-based algorithm was 96.6% for the Apple Watch 6, 95.2% for the AliveCor Kardia Mobile, 96.0% for the Fitbit Sense, 95.7% for the Samsung Galaxy Watch 3 and 93.8% for the Withings Scanwatch, respectively (Figure 1, left). While diagnostic accuracy of the DNN-based algorithm was similar compared to each manufacturer's individual algorithm, the proportion of SL ECGs with a conclusive diagnosis was significantly higher for all smart devices when using the DNN-based algorithm, p&lt;0.001 (Figure 1, right). As complementary analysis, we assessed sensitivity and specificity detection capabilities in both algorithms (Figure 2).

Conclusion

In this clinical validation, a DNN-based algorithm reported significantly more conclusive diagnoses for each smart device compared to the manufacturers' algorithms, whilst showing similarly high accuracy in the detection of AF compared to the cardiologist-interpreted standard 12-lead ECG. Given further validation, SL ECG assisted rhythm interpretation through a cross-platform AI-algorithm presents a promising clinical value for AF detection and offers a possible solution for managing the data surge for smart device-acquired ECGs.

Funding Acknowledgement

Type of funding sources: None.

Echocardiographic pattern of left ventricular function recovery in tachycardia-induced cardiomyopathy patients

Background

Tachycardia-induced Cardiomyopathy (TIC) represents a reversible type of cardiomyopathy (CM) that is underdiagnosed. Prior pilot studies suggested a specific left ventricular (LV) function recovery pattern in TIC patients. Cardiac chamber remodeling in TIC, however, remains incompletely understood.

Purpose

We aimed to explore differences in LV dimensions and functional recovery in TIC patients when compared to a control group of patients with other forms of CM and functional recovery.

Methods

We identified patients with reduced left ventricular ejection fraction (≤50%) and/or atrial fibrillation or flutter treated between 2015 and 2022. Patients had at least two serial transthoracic echocardiographies (TTE). The minimal interval between the TTEs had to be at least 3 months, and the left ventricular ejection fraction (LVEF) had to either improve (≥15% in absolute value) or normalize (LVEF at follow-up ≥50%). Patients were then divided into two groups: A) patients with atrial fibrillation or atrial flutter at baseline and sinus rhythm at follow-up. These patients were assumed to have TIC. B) Patients with sinus rhythm at both baseline and follow-up, consisting of patients with other forms of CM. The change in ventricular dimensions and function (indexed left ventricular end-systolic – LVESDI, end-diastolic diameters – LVEDDI – and volumes – LVEDVI, LVEF, and fractional shortening – FS) were compared within and across group A and B at baseline and at follow-up. The groups were compared using Kruskal (for independent data) and Wilcoxon (for paired data) tests. A p&lt;0.05 was considered significant.

Results

A total of 261 patients were included (34% female, median age 68 years). The median time between TTEs was 25 months. 104 (39.8%) patients were considered to suffer from TIC and 157 (60.2%) patients were considered to suffer from other forms of CM. The changes in ventricular dimensions and function in both groups are shown in Figure 1 and Table 1. The TIC group showed no improvement in LVEDVI from baseline to the follow-up examination, while the control group showed significant improvement in LVEDVI (1.7% [−24.7, 22.8] vs. 12.4% [−7.1, 29.3], p=0.008). There was no difference in LVEDDI recovery between TIC and control patients (1.7% [−7.3, 10.3] versus 3.1% [−5.4, 10.2], p=0.578).

Conclusions

TIC patients have a specific pattern of functional recovery with similar improvements in systolic function and diameters compared with patients with other CMs, while diastolic parameters remained impaired.

Funding Acknowledgement

Type of funding sources: None.

Bone morphogenetic protein 10 as predictor for adverse outcomes in patients with atrial fibrillation

Background

Patients with atrial fibrillation (AF) face an increased risk of death and major adverse cardiovascular events (MACE). Bone morphogenetic protein 10 (BMP10) is a novel atrial-specific biomarker, but data about its prognostic value in AF patients are lacking.

Purpose

We aimed to assess the predictive value of BMP10 for death and MACE in AF patients in comparison to N-terminal prohormone of B-type natriuretic peptide (NT-proBNP).

Methods

Baseline concentrations of BMP10 and NT-proBNP were measured in stable patients with AF enrolled in Swiss-AF, a prospective multicenter observational cohort study. Primary outcomes were all-cause death and MACE (composite of heart failure hospitalization, cardiovascular death, stroke, systemic embolism, myocardial infarction). Measures of discriminative power were used to compare multivariable Cox proportional hazard models using the different biomarkers.

Results

A total of 2219 AF patients were included with a median follow-up of 4.3 years (IQR 3.9, 5.1). Mean age was 73±9 years and 27% were women. Incidence rate per 100 patient-years of all-cause death and MACE increased across BMP10 quartiles (Figure 1). In the multivariable adjusted Cox proportional hazard model, the hazard ratio (HR) and 95% confidence interval (CI) of BMP10 was 1.60 (1.37; 1.87) to predict all-cause death, and 1.54 (1.35; 1.76) to predict MACE. For all-cause death, the C-index (95% CI) was 0.783 (0.763; 0.809) for BMP10, 0.784 (0.765; 0.810) for NT-proBNP, and 0.789 (0.771; 0.815) for both biomarkers combined. For MACE, the C-index (95% CI) was 0.732 (0.715; 0.754) for BMP10, 0.747 (0.731; 0.768) for NT-proBNP, and 0.750 (0.734; 0.771) for both biomarkers combined. When grouping patients according to clinical used NT-proBNP categories (&lt;300, 300–900, &gt;900 ng/l), higher incidence rates and adjusted HRs were observed for the primary outcomes in patients with high BMP10 in the categories of low NT-proBNP (all-cause death aHR 2.28 [1.15; 4.52], MACE aHR 1.88 [1.07; 3.28]) and high NT-proBNP (all-cause death aHR 1.61 [1.14; 2.26], MACE aHR 1.38 [1.07; 1.80]) (Figure 2).

Conclusion

The novel atrial-specific biomarker BMP10 strongly predicts all-cause death and MACE in patients with AF. BMP10 provides additional prognostic information in low- and high-risk patients according to NT-proBNP stratification.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation, Swiss Heart Foundation

Comparison of the accuracy of contact force measurement in four commercially available force-sensing ablation catheters

Funding Acknowledgements

Type of funding sources: None.

Background

Contact force-sensing catheters are widely used for ablation of cardiac arrhythmias. They allow precise quantification of catheter-to-tissue contact, which is an important determinant of lesion size and durability. Moreover, contact force information reduces the risk for cardiac perforation and is used for estimation of lesion size. However, the accuracy of contact force sensors across different manufacturers has not been validated independently.

Objective

To compare the accuracy and reproducibility of different force sensing catheters used in cardiac electrophysiology procedures.

Methods

A force measurement setup containing a heated saline water bath and a catheter fixation mechanism was constructed. The setup allows to accurately measure forces applied to a platform with the catheter. We studied four different catheter models, equipped with the following, unique force-measurement technologies (figure 1): 1) multiple-fiber optical sensor; 2) single-fiber optical sensor; 3) inductive sensor; and 4) magnetic field sensors. For each model, we assessed three catheters. Repeated measurements within the force range of 0g to 60g and at electrode-tissue contact angles of 0°, 45°, and 90° were performed and validated against the force measurement unit of our measurement setup.

Results

For each catheter, at least 500 measurements at different contact forces (equally distributed across the measurement range of 0 to 60 grams) were performed. Correlation of measured-force to real-force was ρSpearman=0.99 for MFOS, ρSpearman=0.98 for SFOS, ρSpearman=0.99 for IS, and ρSpearman=0.98 for MFS. MFS and SFOS showed a higher variance for high forces and increased intra-catheter variability compared to MFOS and IS. IS overestimated higher contact force at 0° and 30°. MFS and SFOS underestimated contact force for higher forces at 30° and 45° (figure 2). Within a clinical range of 5g to 40g, the catheters reached the following root-mean-square-error, independent of contact angle: MFOS 0.88g ±0.68g, SFOS 2.15g ±1.74g, IS 0.88g ±0.72g, and MFS 1.13g ±1.01g.

Conclusion

Measured contact by force-sensing catheters correlates well with true exerted electrode-tissue force. Despite an excellent overall correlation, some technologies may be prone to significant errors at higher forces (&gt;10g under-/overestimation of true contact force) with potential clinical consequences related to increased risk of perforation.

An automatic single beat algorithm to discriminate farfield from nearfield bipolar voltage electrograms from the pulmonary veins

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): “Stiftung für Herzschrittmacher und Elektrophysiologie” Basel, Switzerland

Background

Confirmation of pulmonary vein (PV) isolation (PVI) during ablation of atrial fibrillation can be challenging due to superimposition of nearfield (NF) PV and farfield (FF) atrial bipolar voltage electrograms (BVE).

Purpose

To develop an automatic algorithm allowing to discriminate PV nearfield (PV-NF) from atrial farfield (atrial-FF) BVE from a circular mapping catheter during cryoballoon (CB) PVI based on a single-heartbeat analysis.

Methods

BVEs from a decapolar inner-lumen diagnostic catheter (Achieve, Medtronic) during CB PVI were manually classified as PV-NF, atrial-FF and combined FF-NF signal based on the characteristics and disappearance of the PV signal during isolation (Figure, upper row). BVE power spectra were computed using the fast Fourier transform (FFT) and the automatic classification of PV-NF, atrial-FF and combined FF-NF signals was performed using the power in different frequency bands (Figure, lower row). Support vector machine classifier was used to identify PV-NF BVE due to its highest predictive accuracy for the two classes PV-NF+ (PV-NF only and combined FF-NF) and PV-NF- (atrial-FF only). Validation of the approach was performed by comparison of a subset of 80 random samples, which were classified in addition by five experienced electrophysiologists.

Results

We analysed a dataset of 355 BVEs from 57 patients. The examples were balanced between the two classes PV-NF+ and PV-NF-. The mean duration (95% CI) of the BVE was 58 ms (26 to 86), 70 ms (50 to 100) and 94 ms (71 to 139) for PV NF, atrial-FF and combined FF-NF, respectively. The overall balanced accuracy including BVE from all PVs was 82.7% (95% CI: 80.3% to 85.1%). The analysis on individual PVs showed an accuracy of 96.6%, 85.2%, 80.8%, and 76.9% for the right inferior, right superior, left inferior and left superior PV, respectively. Validation of the algorithm in the subset of 80 patients showed a comparable accuracy, sensitivity and specificity in PV-NF detection between the automatic algorithm and the experienced electrophysiologists (82.8%, 89.2%, and 76.3%, compared to 85.2%, 91.9%, and 78.5%, respectively).

Conclusion

A reliable automatic based classification algorithm to identify PV-NF BVE could be developed based on a single-beat analysis. Real-time applications as well as using other electrode configurations may improve local signal interpretation.

Management of conduction disorders after transcatheter aortic valve implantation: results of an EHRA survey

Funding Acknowledgements

Type of funding sources: None.

Background

Left bundle branch block (LBBB) is common after transcatheter aortic valve implantation (TAVI) and is an indicator of subsequent high-grade atrioventricular block. Consensus regarding a reasonable strategy to manage cardiac conduction disturbances after TAVI has been elusive

Methods

The European Heart Rhythm Association (EHRA) conducted a survey to capture contemporary clinical practice for conduction disorders after TAVI. A 25-item online questionnaire was developed and distributed among the EHRA electrophysiology research network centres.

Results

Of 117 respondents, 44% were affiliated with university hospitals. This survey has revealed that a standardized management protocol for advanced conduction disorders such as LBBB or AVB after TAVR is available in 63% of participating centres. Telemetry was chosen by most participants as the most frequent management strategy for patients with new or preexisting LBBB after TAVI (79%, 70%, respectively, Figure 1). Duration of telemetry in patients with new LBBB varied: 18% chose 24 hours, 35% 48 hours, 27% 72 hours and 20% ≥ 72 hours. Similarly, in patients with new LBBB after TAVI undergoing EP study, the cut-off for a prolonged HV interval for PM implantation was heterogenous among European centers (7.4% ≥ 55ms and 44% ≥ 75ms). Conduction system pacing was chosen as preferred device therapy in patients with LBBB and normal LVEF in 3.7% and in patients with LBBB and reduced LVEF in 5.6%.

Conclusions

The management of conduction disorders after TAVI is very heterogeneous across European centres. Risk stratification strategies vary substantially. The role of conduction system pacing in patients with LBBB after TAVI needs to be defined. There is a considerable room for better uniformity in clinical practice.

Healthy lifestyle and atrial fibrillation recurrence after pulmonary vein isolation

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Data on the relationship of a healthy lifestyle at the time of atrial fibrillation (AF) ablation with AF recurrence is limited.

Purpose

We investigated the association of healthy lifestyle markers with AF recurrence after ablation.

Methods

In 1439 patients undergoing AF ablation at a tertiary university hospital, a lifestyle score was built. The score included categories of BMI, smoking, blood pressure, fish intake, fruits/vegetable intake, alcohol consumption and physical activity. A higher score indicated a healthier lifestyle and patients were grouped into tertiles. Follow-up included 24h-Holter ECGs at 3 and 6 months and 7d-Holter ECGs at 12 months. Survival analyses and Cox-regression models were used to assess associations of individual factors and score-tertiles with AF recurrence.

Results

Mean age was 61.5 years, 25.9% were female and 59.1% had paroxysmal AF. In 941 patients all lifestyle score variables were available: 129, 675 and 137 patients were in the low, intermediate and high lifestyle group, respectively. Over increasing lifestyle groups, patients were more often female (9.3, 23.3, 38.7%; p&lt;0.0001), had less hypertension (70.5, 53.3, 32.9%; p&lt;0.0001), diabetes (15.5, 6.2, 3.7%; p=0.0002), a smaller left atrial diameter (44.1, 41.0, 37.6mm; p&lt;0.0001) and numerically more paroxysmal AF (56.6, 62.4, 69.4%; p=0.32) with no differences in anti-arrhythmic drugs. In survival analyses (Figure), we saw a trend of more recurrences in the healthiest group compared to the unhealthiest group (logrank p=0.06 for low vs high group). Individually, higher fish intake (logrank p=0.04) and lower blood pressure (logrank p=0.02) were associated with AF recurrence. In Cox-regression models the HR (95% CI) for increasing lifestyle groups was 1.21 (0.98; 1.50, p=0.07). In individual models only higher fish intake (1.25 [1.01; 1.55], p=0.045) was associated with AF recurrence.

Conclusion(s): AF recurrence was numerically more frequent in patients with a healthier lifestyle, despite less comorbidities and smaller LA diameters. This paradoxical relationship might be due to lifestyle changes after PVI, differences in PVI efficacy or residual confounding. Further studies are needed to better understand this association.

Amplitude of fibrillatory wave correlates with long-term maintenance of sinus rhythm after ablation in persistent atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Commission for Technology and Innovation (CTI), Switzerland

Background

Amplitude of fibrillatory wave (fWA) on surface ECG is regarded as a predictor of ablation outcome for atrial fibrillation (AF).

Purpose

We sought to investigate whether fWA and its changes during ablation predicts long-term maintenance of sinus rhythm (SR) after wide circumferential isolation of pulmonary veins (WPVI) in persistent AF (peAF).

Methods

41 patients (63±10 y, sustained AF 11±7 months) underwent a de-novo WPVI. A second WPVI was performed in patients with recurrent AF in order to provide complete PV disconnection. We defined "success" as patients who remained in SR after one or two procedures, and "failure" otherwise. 60-sec ECG signals devoid of QRST waves were recorded during the index ablation at baseline and at the end of ablation (end_WPVI, before cardioversion or conversion of AF into SR). fWA was computed on leads V1 and V6b (placed on the pts’ back) as the average difference between the upper and lower envelope of atrial ECG signals.

Results

Over a mean follow-up of 33±9 months, 30 patients remained free from AF (success group), while 11 patients had AF recurrence after 2 WPVIs (failure group). The clinical characteristics (e.g. age, body mass index, left atrial volume or duration in sustained AF) were similar between groups (p &gt; 0.05). The success group displayed significantly higher fWA values at baseline and end_WPVI than that of the failure group (p&lt;0.05, Panel A and B). No significant difference was found between baseline fWA values and those measured at end_WPVI (p &gt; 0.05).

Conclusion

As fWA is independent of PVs contribution, it is a marker of atrial body remodelling. Low fWA values identify patients with peAF unresponsive to WPVI.

Clinical validation of a novel smartwatch for automated detection of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

The Withings Scanwatch is a novel smartwatch able to record an intelligent (i)ECG with automated detection of AF. While the iECG function from three major manufacturers have been extensively investigated, there is a paucity of data regarding the performance of the iECG function of the Withings Scanwatch.

Methods

We performed a prospective, observational study enrolling consecutive patients presenting to a cardiology service at a tertiary referral center. The aim was to assess the diagnostic performance of the iECG function of the Withings Scanwatch to detect AF compared to a simultaneously acquired cardiologist-interpreted 12-lead ECG. All iECG rhythm strips and 12-lead ECGs were anonymized and distributed to two blinded cardiologists who independently interpreted each tracing and assigned a diagnosis of sinus rhythm, AF or unclassified.

Results

iECGs and 12-lead ECGs were simultaneously recorded in 319 patients (67 yo (IQR 54-76), 48% female, Figure 1). Using the automated algorithm, rhythm was deemed inconclusive in 44 patients (14%). Overall, AF was present in 34 patients (11%). Among the tracings where the algorithm provided a diagnosis, it correctly identified AF with 76% (95%CI 55-91%) sensitivity, 99% (95%CI 97-100%) specificity, and a Kappa (K) coefficient of 0.72 when compared with cardiologist-interpreted 12-lead ECGs. Among patients in sinus rhythm, 3 were labeled AF (false-positive). From the 44 unclassified recordings, blinded cardiologists were able to correctly diagnose AF with 100% (95%CI 59-100%) sensitivity, 93% (95%CI 77-99%) specificity, and a K coefficient of 0.49. A total of 13 iECG recordings (4.1%) were determined to be noninterpretable by the cardiologists. Of the remaining 306 patients with simultaneous recordings, cardiologist interpretation of the iECG tracings demonstrated 97% (95%CI 84-100%) sensitivity, 99% (95%CI 96-100%) specificity and a K coefficient of 0.75.

Conclusion

Automatic rhythm classification was inferior to manual interpretation of iECGs. We found a lower sensitivity for the detection of AF using the Withings iECG function compared to data published on other devices. Cardiologist-iECG interpretation, however, was highly reliable with a diagnostic accuracy of 98% (95%CI 96-100%). Clinical interpretation of iECG readings by a cardiologist is therefore strongly encouraged

Magnetic field interactions of smartwatches and portable electronic devices with cardiovascular implantable electronic devices

Funding Acknowledgements

Type of funding sources: None.

Introduction

Magnetic interference of portable electronic devices (PEDs), such as state-of-the-art mobile phones, with cardiovascular implantable electronic devices (CIEDs) has been reported.

Purpose

The aim of the study was to quantify the magnetic fields of latest generation Smartwatches and other PEDs and to evaluate and predict their risk of CIED interactions.

Method

High resolution magnetic field characterization of five smartwatches able to record an ECG Apple Watch, Series 6 and 7, Fitbit Sense, Samsung Galaxy Watch 3, and Withings Move ECG Watch was performed using a magnetic field camera consisting of 1024 calibrated three axis Hall sensors. Maximal distance of 1 mT (10 Gauss) field strength and 1 mT volume was calculated. Ex vivo measurements of the minimal safety distance (MSD) at which no mode switch can be observed between six representative CIEDs and the PEDs was performed. Results were compared to other PEDs, such as digital pens, headsets and their cases, and a Smartphone.

Result

Maximal 1 mT distances ranged between 10 mm and 19 mm, and 1 mT volumes between 6 cm3 and 19 cm3. The smartwatches and PEDs with measured 1 mT distance 15 mm (B: Microsoft surface pen, C: Airpods Pro case) showed device interaction up to &gt; 15 mm (Figure). Linear regression analysis showed an inverse linear relationship of the MSD with 1 mT distance (B coefficient: 0.459; 95% CI: 0.246-0.672; p&lt;0.001) but not with the volume (p=0.842)

Conclusions

Standardized measurements of the 1 mT field distance and volume is feasible and has the potential to assess the risk of CIED interaction. Smartwatches seem to be safe in contrast to other PEDs such as the Microsoft surface pen or Airpods Pro case with high 1mT volumes and maximal distances with regards to CIED interaction.

Left bundle branch area pacing guided by continuous uninterrupted monitoring of unipolar pacing characteristics

INTRODUCTION

During left bundle branch area pacing (LBBAP) lead implantation, intermittent monitoring of unipolar pacing characteristics confirms LBB capture and can detect septal perforation. We aimed to demonstrate that continuous uninterrupted unipolar pacing from an inserted lead stylet (LS) is feasible and facilitates LBBAP implantation.

METHODS

Thirty patients (mean age 76 ± 14 years) were implanted with a stylet-driven pacing lead (Biotronik Solia S60). In 10 patients (comparison-group) conventional implantation with interrupted unipolar pacing was performed, with comparison of unipolar pacing characteristics between LS and connector-pin (CP)-pacing after each rotation step. In 20 patients (uninterrupted-group) performance and safety of uninterrupted implantation during continuous pacing from the LS were evaluated.

RESULTS

In the comparison group, LS and CP-pacing impedances were highly correlated (R²  = 0.95, p < .0001, bias 12 ± 37 Ω) with comparable sensed electrograms and paced QRS morphologies. In the uninterrupted group, continuous LS-pacing allowed beat-to-beat monitoring of impedance and QRS morphology to guide implantation. This resulted in successful LBBAP in all patients, after a mean of 1 ± 0 attempts, with mean threshold 0.81 ± 0.4 V, median sensing 6.5 mV [IQR 4.4-9.5], and mean impedance 624 ± 101 Ω. Positive LBBAP-criteria were seen in all patients with median paced QRS duration of 120 ms [IQR 112-152 ms] and median pLVAT 73 ms [IQR 68-80.5 ms]. No septal perforation occurred.

CONCLUSION

Unipolar pacing from the LS allows accurate determination of pacing impedance and generates similar paced QRS morphologies and sensed electrograms to CP pacing. Continuous LS pacing allows real-time monitoring of impedance and paced QRS morphology, which facilitates safe and successful LBBAP lead implantation.

Safety of very high-power short-duration radiofrequency ablation for pulmonary vein isolation: a two-centre report with emphasis on silent oesophageal injury

AIMS

Very high-power short-duration (vHPSD) via temperature-controlled ablation (TCA) is a new modality to perform radiofrequency pulmonary vein isolation (PVI), conceivably at the cost of a narrower safety margin towards the oesophagus. In this two-centre trial, we aimed to determine the safety of vHPSD-based PVI with specific emphasis on silent oesophageal injury.

METHODS AND RESULTS

Ninety consecutive patients with atrial fibrillation (AF) underwent vHPSD-PVI (90 W, 3-4 s, TCA) using the QDOT MICRO catheter, in conjunction with the nGEN (Bad Neustadt, n = 45) or nMARQ generator (Bruges, n = 45). All patients underwent post-ablation oesophageal endoscopy. Procedural parameters and complications were recorded. A subgroup of 21 patients from Bad Neustadt underwent cerebral magnetic resonance imaging (cMRI) to detect silent cerebral events (SCEs). Mean age was 67 ± 9 years, 59% patients were male, and 66% patients had paroxysmal AF. Pulmonary vein isolation was obtained in all cases after 96 ± 29 min. No steam pop, cardiac tamponade, stroke, or fistula was reported. None of the 90 patients demonstrated oesophageal ulceration (0%). Charring was not observed in the nMARQ cohort (0% vs. 11% in the nGEN group). In 5 out of 21 patients (24%), cMRI demonstrated SCE (exclusively nGEN cohort).

CONCLUSION

Temperature-controlled vHPSD catheter ablation allows straightforward PVI without evidence of oesophageal ulcerations or symptomatic complications. Catheter tip charring and silent cerebral lesions when using the nGEN generator have led to further modification.

Predictors of recurrence after durable pulmonary vein isolation for paroxysmal atrial fibrillation

AIMS

Catheter 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 RESULTS

Patients 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.

CONCLUSION

The 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.

Paroxysmal atrial fibrillation with high vs. low arrhythmia burden: atrial remodelling and ablation outcome

AIMS

The relation between atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF), atrial remodelling, and efficacy of catheter ablation (CA) is unknown. We investigated whether high vs. low-burden paroxysmal AF patients have distinct clinical characteristics or electro-mechanical properties of the left atrium (LA) and whether burden impacts outcome of CA.

METHODS AND RESULTS

Atrial tachyarrhythmia burden, defined as the percentage of time spent in ATA, was assessed by insertable cardiac monitors in 105 patients before and after CA. Clinical characteristics and electro-mechanical properties of LA were compared between patients with high vs. low ATA burden. Catheter ablation efficacy was assessed by reduction in ATA burden and 1-year freedom from any ATA. Median ATA burden was 2.7% (highest tertile 9.3%). Clinical characteristics and electrical properties of LA (refractoriness, conduction velocity, low voltage) did not differ between high (≥9.3%) vs. low ATA burden (<9.3%) patients. High ATA burden patients had larger LA diameter (46.5 ± 6 vs. 42.5 ± 6mm, P < 0.01), volume (93.8 ± 22 vs. 80.4 ± 21mL, P = 0.01), and lower LA reservoir and contractile strain (19.7 ± 6 vs. 24.7 ± 6%, P < 0.01; 10.3 ± 3 vs. 12.8 ± 4%, P = 0.01). Catheter ablation reduced ATA burden by 100% (100-100) in both groups (P = 1.0). Freedom from ATA after CA was equally high (83% vs. 89%, P = 0.38).

CONCLUSION

Paroxysmal AF patients with high ATA burden have altered LA mechanical properties, reflected by larger size and impaired function. Despite mechanical remodelling of the atria, they are excellent responders to CA. Most likely the lack of fibrosis and/or advanced electrical remodelling explain why pulmonary veins remain the dominant trigger for AF in this patient cohort.

Non-invasive predictors for infranodal conduction delay in patients with left bundle branch block after transcatheter aortic valve replacement

Funding Acknowledgements

Type of funding sources: None.

Introduction

Left bundle branch block (LBBB) is the most common conduction disorder after transcatheter aortic valve replacement (TAVR) with an increased risk of atrioventricular (AV) block. The aim of the current study was to identify non-invasive predictors for infranodal conduction delay in patients with LBBB.

Methods

We analyzed consecutive patients undergoing TAVR with pre-existing or new-onset LBBB between August 2014 and August 2020. His ventricular (HV) interval measurement was performed on day 1 after TAVR. Baseline, procedural, as well as surface and intracardiac electrocardiographic parameters were included. Infranodal conduction delay was defined as HV interval &gt;55 ms.

Results

Of 825 patients screened after TAVR, 151 patients (82 ± 6 years, 39% male) with LBBB were included. Among these, infranodal conduction delay was observed in 25%. ΔPR (difference in PR interval after and before TAVR), PR and QRS duration after TAVR were significantly longer in the group with HV prolongation. In a multivariate analysis in patients with sinus rhythm (n = 131), ΔPR (OR per 10 ms increase: 1.52; 95% CI: 1.19-2.01; p = 0.002) was the only independent factor associated with infranodal conduction delay. The AUC of the ROC curve was 0.724 (95% CI) for ΔPR. A change in PR interval by 20 ms yielded a sensitivity of 26% and specificity of 83% with a positive predictive value of 45% and a negative predictive value of 84% to predict HV prolongation.

Conclusions

Simple analysis of surface ECG and a calculated ΔPR &lt;20ms can be used as predictor for the absence of infranodal conduction delay in post-TAVR patients with LBBB. Abstract Figure HV

Efficacy and safety of a high power short duration ablation-index guided protocol for pulmonary vein isolation using a single catheter

Funding Acknowledgements

Type of funding sources: None.

Background

Catheter ablation for atrial fibrillation (AF) is the most common performed electrophysiological procedure. The cost of this procedure remains high.

Purpose

To improve health care utilization, we aimed to compare the efficacy and safety of a minimalistic, streamlined single radiofrequency catheter ablation approach using high power short duration ablation-index guided protocol (HPSD) vs. a standard single catheter protocol.

Methods

A circular mapping catheter free PVI with a single transseptal puncture was performed in 91 patients. A CARTO fast anatomical map was performed with the ablation catheter. Pacing maneuvers were used to confirm exit block. Procedural characteristics and success rates were compared using HPSD- vs. a standard ablation-protocol. Freedom from recurrence was defined as a 1-year absence of AF episodes &gt; 30 s, beyond the 3-month-blanking-period.

Results

Using the HPSD-protocol the median procedure, map and RF ablation time were significantly shorter in the HPSD group compared to the standard group, 84 (IQR 76-100) vs. 118 minutes (IQR 104-141), 12 (IQR 10-16) vs. 18 minutes (IQR 15-21) and 1036 (898-1184) vs. 1949 seconds (IQR 1693-2261), respectively, P &lt; .001 for all. First-pass-PVI was achieved using the HPSD-protocol in 23 patients (74%) and the standard-protocol in 30 patients (53%), p = 0.08. Localization of conduction gaps are illustrated for the HPSD-protocol and the standard-protocol in Figure 1. The residual gap was identified using the ablation catheter only in all patients. No procedural complication were observed. At 12 months follow-up, 60 (89.6%) patients remained free from AF with no differences between groups.

Conclusions

A minimalistic, CMC-free HPSD-guided PVI approach is very efficient, safe, likely cost-saving, and associated with excellent clinical outcomes at 1 year. Abstract Figure 1

Biosense Webster's QDOT Micro™ radiofrequency ablation catheter

The QDOT Micro™ catheter (Biosense Webster, Inc., CA, USA) is a new radiofrequency ablation catheter based on the SmartTouch SF™ (Biosense Webster, Inc.). It combines diffuse external irrigation with six thermocouples located within the outer metal shell and three additional microelectrodes in a 3.5 mm-tip contact force radiofrequency catheter. This article focuses on the different characteristics of the catheter, which incorporates the ability of high power delivery, irrigation flow control based on temperature sensing through the six thermocouples and the generation of microelectrograms. An outline of its performance in preclinical and clinical setting is presented, showing promising results, especially concerning procedural efficiency and short-term safety. Additional studies need to confirm long-term effectiveness, and durability studies should evaluate whether superiority on a lesion quality level can be achieved.

Repositioning and extraction of stylet-driven pacing leads with extendable helix used for left bundle branch area pacing

Conventional stylet-driven leads with extendable helix can be implanted successfully for left bundle branch area pacing (LBBAP) with a low acute complication rate. We report two cases in which lead repositioning after a first unsuccessful attempt to LBBAP was associated with fracture of the helix rotating mechanism and failure to fully extract the pacing lead.

Singlet-Contrast Magnetic Resonance Imaging: Unlocking Hyperpolarization with Metabolism*

Hyperpolarization-enhanced magnetic resonance imaging can be used to study biomolecular processes in the body, but typically requires nuclei such as 13 C, 15 N, or 129 Xe due to their long spin-polarization lifetimes and the absence of a proton-background signal from water and fat in the images. Here we present a novel type of 1 H imaging, in which hyperpolarized spin order is locked in a nonmagnetic long-lived correlated (singlet) state, and is only liberated for imaging by a specific biochemical reaction. In this work we produce hyperpolarized fumarate via chemical reaction of a precursor molecule with para-enriched hydrogen gas, and the proton singlet order in fumarate is released as antiphase NMR signals by enzymatic conversion to malate in D2 O. Using this model system we show two pulse sequences to rephase the NMR signals for imaging and suppress the background signals from water. The hyperpolarization-enhanced 1 H-imaging modality presented here can allow for hyperpolarized imaging without the need for low-abundance, low-sensitivity heteronuclei.

Empirical superior vena cava isolation in patients undergoing redo- catheter ablation procedure after recurrence of atrial fibrillation

Background/Introduction

Extra pulmonary vein (PV) foci may trigger AF recurrence after an initially successful PVI. Superior vena cava (SVC) catheter ablation (CA) may therefore offer a treatment target in order to improve success rates.

Purpose

The purpose of this study was to evaluate the potential benefit of empirical SVC isolation in addition to PVI in patients undergoing a second CA after index PVI.

Methods

We retrospectively analyzed consecutive patients scheduled for a second CA because of a recurrence of symptomatic AF. Redo-CA was performed with a 3D electroanatomic mapping system and point-by-point ablation using RF energy in the range between 25 W and 30 W. In case of persistent isolation of all PVs, only SVCI was performed. In case of reconnection of vein(s), a wider antral re-isolation was performed. Redo-PVI (PVI-group) or Redo-PVI plus SVC isolation (SVCI) (PVIplusSVCI-group) were performed at the discretion of the operator. No additional targets were allowed. The endpoint of all procedures was elimination of the PV signals confirmed by a circular mapping catheter at the level of the PV ostium and elimination of all signals in the SVC in case of SVCI. Recurrence of AF during a follow-up of 12 months is presented.

Results

We analyzed 191 patients (age 61±10 years, 30% female, BMI 27±5 kg/m2, LVEF 56±9%, PLAX 41±7 mm, paroxysmal 61%). Whereas 148 (78%) patients underwent Redo-PVI only, 31 patients (16%) underwent PVI plus SVCI, and in 12 patients (6%) SVCI only was performed. Baseline characteristics did not differ significantly between the two groups. In the PVI-group, 79% were recurrence-free compared to 65% (see Kaplan-Meier curve: log rank p=0.011) in the PVIplusSVCI-group. The RF time of the PVI group focusing on the wide antral re-isolation of vein(s) was significantly higher than for the PVIplusSVCI-group (819±494 s versus 458±444 s; p&lt;0.001).

Conclusion

Additional empirical SVCI at redo-PVI in patients with symptomatic AF recurrence does not lead to an increase in freedom from AF recurrence. Focusing on an additional “wider antral” re-isolation may be more effective.

Kaplan-Meier Survival Curves for Recurre

Funding Acknowledgement

Type of funding source: None

A simple method to detect phrenic nerve impairment during cryoballoon ablation of atrial fibrillation using aVF in the standard surface ECG

Background

Phrenic nerve palsy (PNP) is the most common complication in cryoballoon ablation of atrial fibrillation. Monitoring techniques such as compound motor action potential (CMAP) measurements using additional leads, or catheters positioned in the subdiaphragmatic hepatic vein or the esophagus have demonstrated to be effective to prevent PNP.

Purpose

This study investigates the safety and feasibility of a simple monitoring strategy using the lead aVF of the standard surface 12 lead ECG for CMAP monitoring to prevent PNP.

Methods

In 263 continuous patients undergoing cryoballoon ablation, a decapolar catheter was placed in the right subclavian vein to stimulate the phrenic nerve during ablation of the right sided pulmonary veins (12V@2.9 ms at 60 bpm). Capture was continuously monitored using the CMAP potential in the inferior aVF lead of the surface ECG and manually by palpation of the abdominal movement. The freeze was terminated early if the amplitude of the aVF signal decrease by &gt;25% in three consecutive beats or if the diaphragmatic contraction decreased.

Results

Phrenic nerve injury documented by a reduction of the signal in aVF was observed in 13 of the 263 patients (5%) during freezes of the right superior pulmonary vein. Reduced diaphragmatic contraction detected by palpation of the abdomen was never observed without previous reduced amplitude in the surface aVF signal and was therefore never the trigger to stop a freeze. In patients with phrenic nerve injury, the mean initial amplitude was 1mV (SD ±0.3mV) and the mean minimal amplitude was 0.3mV (SD ±0.2mV). Mean time to recovery of the aVF amplitude was 160 seconds. Twelve patients (4.6%) showed complete recovery whereas one patient (0.4%) showed only partial recovery, as demonstrated in a sniff test at the end of the procedure. This patient showed no clinical signs of phrenic nerve palsy the following day, and full recovery was demonstrated in a sniff test 3 months later.

Conclusion

Monitoring of CMAP using the aVF signal from a standard 12-lead ECG during phrenic nerve stimulation to reduce the incidence of phrenic nerve palsy is safe and feasible. This technique is readily available during every standard ablation without placing additional electrodes and more sensitive than manual palpation.

aVF signal before and during ablation

Funding Acknowledgement

Type of funding source: None

P956Improved quality of life and symptomatic atrial fibrillation reduction in patients treated with a standardized ablation index workflow

Background/Introduction

The use of a standardized ‘CLOSE’ ablation workflow for pulmonary vein isolation (PVI), with defined inter-tag distance (ITD) with targeted ablation index (AI) values, has been shown in single centre reports to result in good outcomes. The effect of this approach on patients’ quality of life (QoL) has not been studied.

Purpose

To evaluate the effects of paroxysmal atrial fibrillation (PAF) ablation by the CLOSE workflow on QoL and symptomatic AF reduction in the multicenter VISTAX study.

Methods

329 patients with PAF (61.5% male, 61.3 ± 10.1 year) were treated at 17 European centres by point-by-point radiofrequency ablation using the CLOSE protocol to achieve PVI.  An ITD ≤6mm and AI values of ≥400 on the posterior wall and ≥550 on the anterior wall were targeted. The AI value on the posterior wall was lowered as per investigator discretion in case of safety concerns. Patients were monitored for atrial arrhythmia recurrences via weekly and symptom-activated transtelephonic monitoring (TTM), for 12 months post procedure. Patients completed an Atrial Fibrillation Effect on Quality-of-life (AFEQT) questionnaire at their baseline and 12-month follow up visits.

Results

Majority (83.3% [274/329]) of patients experienced freedom from symptomatic atrial recurrence through 12 months. Of the 70 documented recurrences, 34 (49%) were documented by trans-telephonic monitoring only. All domains captured on the AFEQT questionnaire showed improvement with the overall score improving by 25.7, which exceeded the threshold of clinically meaningful improvement (±5) (Table). Patient reported most improvements in PAF control and symptoms relieved. The overall AFEQT score improvement was seen both in patients with or without documented atrial arrhythmia recurrence, with improvement by 21.5 and 26.8, respectively.

Conclusion

PAF ablation using a standardized CLOSE workflow resulted in consistent improvements in QoL. The improved QoL was observed regardless of atrial arrhythmia recurrence likely reflecting the low residual arrhythmia burden in patients with documented recurrence identified only on TTM.

AFEQT Scores Through 12 Months AFEQT Domain Baseline 12 Months Change from Baseline* Daily Activities 59.2 85.3 26.0 Treatment Concerns 62.2 88.1 26.0 Controlling PAF 50.2 87.8 37.5 Symptoms 63.7 89.0 25.1 Symptoms Relieved 52.0 88.4 36.3 Overall AFEQT Score 61.3 87.2 25.7 *only includes patients who completed both baseline and 12 month AFEQT questionnaire

1242The flexibility, ease of using, and leaving curve of a standardized ablation index workflow for catheter ablation of paroxysmal atrial fibrillation

Background/Introduction

The ‘CLOSE’ protocol, incorporating standardized ablation index (AI) targets in conjunction with defined inter-tag distance (ITD) has been shown to improve the acute and long-term success of pulmonary vein isolation (PVI) when treating paroxysmal atrial fibrillation (PAF). The reproducibility and learning curve for this protocol has not been studied.

Purpose

To assess the acute and long-term efficacy of CLOSE PVI across multiple operators (n = 37) in the 17-centre European study ‘VISTAX’.

Methods

329 patients with PAF (61.8% male, 61.3 ± 10.1 years) underwent PVI according to the CLOSE protocol, with target AI values for each lesion of ≥400 on the posterior wall and ≥550 on the anterior wall, and target ITD of ≤6mm. Each 3-dimensional electroanatomic map was evaluated at a core lab where adherence to each of these criteria was assessed. 281/329 patients (85.1%) fulfilled all standardized workflow requirements and were adjudicated as having their PVI per-protocol (PP). First pass PVI and acute effectiveness (adenosine-proof first pass PVI at 30-minute challenge) were recorded. Clinical effectiveness was assessed as freedom from atrial arrhythmia recurrence through 12 months recorded via transtelephonic monitoring (weekly and symptomatically), in addition to holter and electrocardiogram monitoring during 3,6,12 month follow up visits. Learning curve analysis was evaluated on all investigators.

Results

First pass PVI rates were similar in the overall (86%) and PP cohorts (85%), as was acute effectiveness (82% in both cohorts). Freedom from atrial arrhythmia at 12 months too was identical for both cohorts (79%). Total procedure time and total ablation time decreased by an average 8 minutes and 10 minutes respectively after the first procedure and then showed further steady decreases over the number of ablations performed by the investigator (Figure).  The procedural efficiencies and clinical success were reproducible across different centers. No significant deviations were found from individual sites.

Conclusion

The standardized CLOSE workflow is reproducible across centres, and is ‘forgiving’ without impacting on high efficacy of almost 80%. The learning curve is short, suggesting that the excellent clinical results can be replicated widely and easily.

Abstract Figure. Learning Curves- Procedure & Ablation

Identification of repetitive atrial activation patterns in persistent atrial fibrillation by direct contact high-density electrogram mapping

INTRODUCTION

Recent studies have characterized drivers in persistent atrial fibrillation using automated algorithm detection with panoramic endocardial mapping by means of basket catheters. We aimed to identify repetitive atrial activation patterns (RAAPs) during ongoing atrial fibrillation (AF) based upon automated annotation of unipolar electrograms (EGMs) recorded with a high-density regional endocardial contact mapping catheter.

METHODS

In 14 persistent AF patients, high-resolution EGMs were recorded for 30 seconds at sequential PentaRay (Biosense Inc) positions covering the entire biatrial surface. All recordings were reviewed off-line with dedicated software allowing automated annotation of the local activation time of the unipolar fibrillatory EGMs (CARTOFINDER; Biosense Inc). RAAPs were defined as a consistent activation pattern (for ≥3 consecutive beats) of either focal activity with centrifugal spread (RAAP_focal ) or rotational activity across the PentaRay splines spanning the AF cycle length (RAAP_rotational ).

RESULTS

A total of 498 PentaRay recordings were analyzed (35.6 ± 7.6 per patient). The number of PentaRay recordings displaying RAAP was 9.8 ± 3.1 per patient (range = 3-15), of which 2.4 ± 2.4 RAAP_rotational (range = 0-7), and 7.4 ± 4.4 RAAP_focal (range = 1-13). 77% of RAAPs portrayed focal firing. The median number of repetitions per 30 second recording was 11 (range = 3-225) per recording. RAAPs were observed both in the right atrium (RA) (35%) and left atrium (LA) (65%), with the majority being near the left PVs/appendage (35% of all RAAPs) and the superior vena cava/right appendage (23% of all RAAPs).

CONCLUSION

High-resolution, sequential endocardial EGM-based mapping allows identification of RAAPs in persistent AF. In our series, focal firing was the most frequently observed pattern.

P5691Independent assessment if an image-processing service for the treatment of patients with ventricular tachycardias

Background/Introduction

Substrate-based radiofrequency ablation (RFA) in combination with pre-procedural computed tomography (CT) or cardiac Magnetic Resonance Imaging (cMRI) emerged as a promising approach to treat ventricular tachycardias (VT). However, image-processing and 3D reconstruction of the relevant structures to embed them into a 3D electroanatomical mapping (EAM) system is time consuming and requires highly experienced personal and a dedicated software.

Purpose

The aim of the study was to present the first independent experience with a commercially available service of a internet platform in patients referred for RFA of VTs.

Methods

Seven consecutive patients (pts) with ischemic cardiomyopathy (ICM), non- ischemic cardiomyopathy (NICM) and dilated cardiomyopathy (DCM) referred for VT RFA underwent contrast-enhanced dual-energy CT. The anonymized DICOM dataset was uploaded to the internet platform. After processing by the specialists, the dataset was downloaded and exported in a format compatible with the 3D EAM System. The EAM was performed in sinus rhythm using a 3.5mm open-irrigated tip catheter or a magnetic remote 3.5mm open-irrigated tip catheter in combination with the remote magnetic navigation-system. A multipolar high-density mapping catheter was used in 6 pts. Scar was defined as bipolar voltage <0.5 mV, and scar border zone ≥0.5mV and <1.5 mV.

Results of the internet platform-derived wall thinning (WT), scars and the defined substrate based on 3d EAM voltage maps were transferred into a 17-segment model, and the filling of every single segment was rated as 0%, 25%, 50%, 75% and 100%. For analysis, agreement of the filling (percentage) of the individual segments was quantified.

Results

Mean age was 67±8 year, BMI was 28±5 kg/m2 and 86% were males. File transfers and image processing was feasible in all patients. Agreement between the defined substrate (<0,5mV) and WT of 4mm was very good (≥90%) in 3 pts, good (≥75% & <90%) in one patient, moderate (≥50% & <75%) in one patient and poor (<50%) in one patient.

Patient #1 #2 #3 #4 #5 #6 #7 Sex male male male female male male male Age 63y 56y 71y 65y 60y 69y 81y BMI 31kg/m2 32kg/m2 19kg/m2 25kg/m2 28kg/m2 34kg/m2 29kg/m2 LVEF 25% 60% 25% 25% 25% 31% 34% EDVI 123ml/m2 184ml/m2 69ml/m2 114ml/m2 142ml/m2 105ml/m2 75ml/m2 Catheter multipolar high-density + 3.5mm open-irrigated tip 3.5mm open-irrigated tip multipolar high-density + 3.5mm open-irrigated tip multipolar high-density + 3.5mm open-irrigated tip multipolar high-density + magnetic remote 3.5mm open-irrigated tip multipolar high-density + magnetic remote 3.5mm open-irrigated tip multipolar high-density + magnetic remote 3.5mm open-irrigated tip Quality 98% 96% 91% 66% 89% no match 53% Quality = Percentage match between defined substrate and WT.

Superimpose – wall thinning and FAM

Conclusion(s)

Integration of substrate-based segmentation using the service of the internet platform is feasible in daily practice. Agreement between voltage-map based substrate definition and internet platform-based WT was satisfactory in the majority of patients.

P2844Novel temperature guided irrigated ablation catheter: reproducibility of procedural efficiencies and acute success to isolate the pulmonary veins from two multicenter, feasibility studies

Background/Introduction

The novel catheter with 6 thermocouples for real-time temperature monitoring during irrigated radiofrequency ablation was designed to potentially enhance safety and effectiveness of the Smart Touch Surround Flow (STSF) catheter by incorporating real-time temperature sensing. A supplementary, novel algorithm was developed to modulate power to maintain target temperature during high power/short duration ablation (90W, 4s).

Purpose

This sub-analysis was performed to examine consistency and reproducibility of the procedural efficiencies and acute success of the novel catheter with optimized temperature control and microelectrodes in treating paroxysmal atrial fibrillation (PAF) across multiple sites from two initial feasibility studies, in standard (QMODE) and high power/short duration (QMODE+) temperature-control ablation modes.

Methods

The QDOT-MICRO (QMODE, NCT02944968; N=42) and QDOT-FAST (QMODE+, NCT03459196; N=52) studies were both prospective, non-randomized multi-center, clinical investigations completed across 6 and 7 centers, respectively, in Europe. Procedural efficiencies and acute success (PVI via entrance block) was examined across sites within the study.

Results

In the QDOT-MICRO study, median procedure time (105–155 min), RF ablation time (27.7–39.5 min), and fluoroscopy times (2.2–8 min) during QMODE ablation were similar across the 6 sites. In QMODE+ ablation, median procedure time, RF ablation time, and fluoroscopy times all fall within (84–134 min), (4.8–9.7 min) and (1.1–9.6 min), respectively, across the 7 sites. Fluid delivery by the study catheter was low in both studies: QDOT-MICRO 547±278mL (mean ± SD); QDOT-FAST 382±299. mL (mean ± SD); which is 39.1 and 57.4% lower, respectively, than reported in the SMART SF trial. Esophageal temperature probe was used in the majority of patients (30/42 for QDOT MICRO and 51/52 for QDOT-FAST). Acute PVI was successful in 100% of patients in both studies with no deaths or unanticipated AEs.

Conclusion(s)

In both feasibility studies, procedural efficiencies were reproducible across study sites in both QMODE and QMODE+, with 100% acute success and good safety outcomes. Efficiencies are likely to improve with further experience. These results need to be confirmed in larger trials.

Acknowledgement/Funding

Both Studies are Company Sponsored Studies funded by Biosense Webster, Inc.

P979Persistent atrial fibrillation terminated within the left atrium without recurrence at follow-up demonstrates a gradual intracardiac organization during stepwise ablation

Introduction

We previously reported that patients (pts) with recurrence (Rec) after stepwise catheter ablation (step-CA) of persistent atrial fibrillation (pAF) exhibit high bi-atrial intracardiac dominant frequencies (DF) values before ablation, indicative of a severe bi-atrial electro-anatomical remodeling.

Purpose

Herein, we hypothesized that a gradual decrease in DF values during step-CA is associated with pAF termination and maintenance of sinus rhythm (SR) on the long term.

Method

In 40 consecutive pts (61±8 yo, sustained AF duration 19±11 months), pulmonary vein isolation (PVI) and left atrium (LA) ablation were performed until pAF termination or cardioversion. 10-sec intracardiac electrograms (EGMs) epochs were recorded before ablation (BL), during PVI and during complex fractionated atrial electrograms (CFAEs) and linear ablation (post_PVI) in the right atrial (RAA) and left atrial (LAA) appendages and in the coronary sinus (CS). DF was defined as the highest peak within the [3–15] Hz EGM spectrum. Rec was defined as any atrial arrhythmia lasting >30 sec during follow-up (FU).

Results

pAF was terminated within the LA in 70% (28/40, LT) of the pts, while 30% (12/40, NLT) were not. After a mean FU of 34±14 months, all NLT pts had a Rec, while LT pts presented a Rec in 71% (20/28, LT_rec) and remained in SR in 29% (8/28, LT_norec). Figure 1 shows: 1) a gradient in DF values measured in the LAA (panel A), RAA (panel B) and CS (panel C) with the highest values in NLT pts (red), intermediate values in LT_rec pts (yellow) and lowest DF values in LT_norec pts (green); 2) all three groups displayed a gradual intracardiac organization during LA ablation as shown by decreasing DF values (p<0.05, BL vs post_PVI), but the LT_norec pts (green) exhibited the highest relative changes in DF from BL (p<0.05, LT_norec vs NLT, Δ range: −5.31 to −9.69%).

Figure 1. Effect of ablation on DF

Conclusion

Low DF values before ablation and gradual intracardiac organization until pAF termination are associated with maintenance of SR on the long term.

Improving procedural and one-year outcome after contact force-guided pulmonary vein isolation: the role of interlesion distance, ablation index, and contact force variability in the 'CLOSE'-protocol

Aims

We have recently shown that a contact force (CF)-guided ablation protocol respecting region-specific criteria of lesion contiguity and lesion depth ('CLOSE' protocol) is associated with high incidence of acute durable pulmonary vein (PV) isolation (PVI) and a high single-procedure arrhythmia-free survival at 1 year. In the present study, we compared efficiency, safety, and efficacy of 'CLOSE'-guided PVI to conventional CF-guided PVI (CONV-CF).

Methods and results

Fifty consecutive paroxysmal atrial fibrillation (AF) patients underwent PV encircling using a CF-sensing catheter targeting an interlesion distance (ILD) ≤6 mm and ablation index (AI) ≥400 and ≥550 at posterior and anterior wall ('CLOSE' group). Results were compared to the last 50 patients undergoing 'CONV-CF'. All patients underwent adenosine testing after PVI. Arrhythmia recurrence was defined as any atrial tachyarrhythmia (ATA) >30 s on Holter at 3, 6, and 12 months. Clinical characteristics did not differ. Contact force variability was comparable in between both groups (proportion of applications with intermittent contact 2% in 'CLOSE' vs. 1% in CONV-CF, P = 0.67). In the 'CLOSE' group, procedure time and radiofrequency (RF) time per circle were shorter (respectively 149 ± 33 min vs. 192 ± 42 min, P < 0.0001 and 18 ± 4 min vs 28 ± 7.5 min, P < 0.0001) and incidence of adenosine-proof isolation was higher (97% vs. 82%, P < 0.001). No complications were observed in the 'CLOSE' group, one tamponade in the 'CONV-CF' group. At 12 months, single-procedure freedom from ATA was 94% in 'CLOSE' vs. 80% in 'CONV-CF' group (P < 0.05). In both groups, the majority of reconnections at repeat were associated with either ILD > 6 mm and/or AI < 400/550 (100% vs. 83%, P = 0.99).

Conclusion

'CLOSE'-guided PVI improves procedural and 1 year outcome in CF-guided PVI while shortening procedure time. Improvement cannot be explained by differences in CF variability and is most likely due to the strict application of criteria for contiguity and ablation index. A randomized controlled trial is needed to exclude the possible contribution of a learning curve.

Evaluation of left atrial linear ablation using contiguous and optimized radiofrequency lesions: the ALINE study

Aims

Achieving block across linear lesions is challenging. We prospectively evaluated radiofrequency (RF) linear ablation at the roof and mitral isthmus (MI) using point-by-point contiguous and optimized RF lesions.

Methods and results

Forty-one consecutive patients with symptomatic persistent AF underwent stepwise contact force (CF)-guided catheter ablation during ongoing AF. A single linear set of RF lesions was delivered at the roof and posterior MI according to the 'Atrial LINEar' (ALINE) criteria, i.e. point-by-point RF delivery (up to 35 W) respecting strict criteria of contiguity (inter-lesion distance ≤ 6 mm) and indirect lesion depth assessment (ablation index ≥550). We assessed the incidence of bidirectional block across both lines only after restoration of sinus rhythm. After a median RF time of 7 min [interquartile range (IQR) 5-9], first-pass block across roof lines was observed in 38 of 41 (93%) patients. Final bidirectional roof block was achieved in 40 of 41 (98%) patients. First-pass block was observed in 8 of 35 (23%) MI lines, after a median RF time of 8 min (IQR 7-12). Additional endo- and epicardial (54% of patients) RF applications resulted in final bidirectional MI block in 28 of 35 (80%) patients. During a median follow-up of 396 (IQR 310-442) days, 12 patients underwent repeat procedures, with conduction recovery in 4 of 12 and 5 of 10 previously blocked roof lines and MI lines, respectively. No complications occurred.

Conclusion

Anatomical linear ablation using contiguous and optimized RF lesions results in a high rate of first-pass block at the roof but not at the MI. Due to its complex 3D architecture, the MI frequently requires additional endo- and epicardial RF lesions to be blocked.

Evaluation of a simple technique aiming at optimizing point-by-point isolation of the left pulmonary veins: a randomized study

Aims

We sought to evaluate the efficacy and the safety of a simple technique for stabilizing the ablation catheter during anterior pulmonary vein (PV) encirclement in patients ablated for paroxysmal atrial fibrillation. This consisted of bending the ablation catheter in the left atrium, creating a loop that was cautiously advanced together with the long sheath at the ostium and then within the left superior PV. The curve was then progressively released to reach a stable contact with the anterior part of the left PVs.

Methods and results

Eighty consecutive patients (age 64 ± 11 years, left atrial diameter 43 ± 8 mm) undergoing ‘CLOSE’-guided PV isolation were prospectively randomized into two groups depending on whether the loop technique was used or not. When using the loop technique, the encirclement of the left PVs was shorter [20 min (interquartile range, IQR 17–24) vs. 26 min (IQR 18–33), P < 0.01] with a high rate of first pass isolation [(100%) vs. (97%), P = 0.9] and adenosine proof isolation [(93%) vs. (95%), P = 0.67]. Most specifically, at the anterior part of the left PVs, there were less dislocations [0 (IQR 0–0) vs. 1 (IQR 0–4), P < 0.001], radiofrequency duration was shorter (272 ± 85 s vs. 378 ± 122 s, P < 0.001), force-time integral was higher [524 gs (IQR 427–687) vs. 398 gs (IQR 354–451), P < 0.001], average contact force was higher [20 g (IQR 13–27) vs. 11g (IQR 9–16), P < 0.001], and impedance drop was higher [12 Ω (IQR 9–19) vs. 10 Ω (IQR 7–14), P < 0.001].

Conclusion

This study describes a simple technique to facilitate catheter stability at the anterior part of the left PVs, resulting in more efficient left PV encirclement without compromising safety.

Failure to detect life-threatening arrhythmias in ICDs using single-chamber detection criteria

BACKGROUND

There are anecdotal reports of sudden death despite a functional implantable cardioverter defibrillator (ICD). We sought to describe scenarios leading to fatal or near-fatal outcome due to inappropriately inhibited ICD therapy in devices programmed with single-chamber detection criteria.

METHODS

Programmed settings, episode lists, and intracardiac electrograms from 24 patients with a life-threatening event (n = 12) or fatal outcome (n = 12) related to failed ventricular arrhythmia detection were used to clarify the underlying scenario.

RESULTS

Fifty episodes of failed ventricular arrhythmia detection were identified and categorized into six scenarios: (1) spontaneous ventricular tachycardia (VT) or ventricular fibrillation (VF) with a rate below the detection limits, (2) misclassification of polymorphic VT (PVT) or VF as supraventricular tachycardia (SVT), (3) misclassification of VT/VF as cluster of nonsustained VT episodes, (4) misclassification of monomorphic VT (MVT) as SVT, (5) inappropriate shock abortion, and (6) false termination detection. These scenarios occurred respectively 6, 9, 3, 9, 8, and 15 times. In 9/9 (100%) patients with PVT/VF classified as SVT, rate stability was active for rates ranging from 222 to 250 beats/min. MVT detected as SVT was due to the sudden onset criterion in 7/9 (78%) patients and twice a consequence of the rate stability criterion active for rates ranging from 200 to 250 beats/min.

CONCLUSION

We describe six scenarios leading to failure of ventricular arrhythmia detection in a single-chamber detection setting withholding life-saving therapy. These scenarios are more likely to occur with high-rate programming and long detection times, especially if combined with rate stability and sudden onset.