Pulmonary vein reconnection mapping with Advisor HD Grid demonstrating local EGM which were not visible on Tacticath ablation catheter

Recurrences of Atrial Fibrillation Despite Durable Pulmonary Vein Isolation: The PARTY-PVI Study

BACKGROUND

Recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI) are mainly due to pulmonary vein reconnection. However, a growing number of patients have AF recurrences despite durable PVI. The optimal ablative strategy for these patients is unknown. We analyzed the impact of current ablation strategies in a large multicenter study.

METHODS

Patients undergoing a redo ablation for AF and presenting durable PVI were included. The freedom from atrial arrhythmia after pulmonary vein-based, linear-based, electrogram-based, and trigger-based ablation strategies were compared.

RESULTS

Between 2010 and 2020, 367 patients (67% men, 63±10 years, 44% paroxysmal) underwent a redo ablation for AF recurrences despite durable PVI at 39 centers. After durable PVI was confirmed, linear-based ablation was performed in 219 (60%) patients, electrogram-based ablation in 168 (45%) patients, trigger-based ablation in 101 (27%) patients, and pulmonary vein-based ablation in 56 (15%) patients. Seven patients (2%) did not undergo any additional ablation during the redo procedure. After 22±19 months of follow-up, 122 (33%) and 159 (43%) patients had a recurrence of atrial arrhythmia at 12 and 24 months, respectively. No significant difference in arrhythmia-free survival was observed between the different ablation strategies. Left atrial dilatation was the only independent factor associated with arrhythmia-free survival (HR, 1.59 [95% CI, 1.13-2.23]; P=0.006).

CONCLUSIONS

In patients with recurrent AF despite durable PVI, no ablation strategy used alone or in combination during the redo procedure appears to be superior in improving arrhythmia-free survival. Left atrial size is a significant predictor of ablation outcome in this population.

High-density electroanatomic mapping with grid catheter in pediatrics and congenital heart disease

BACKGROUND

The Advisor™ HD Grid mapping catheter (Abbott Laboratories; Chicago, IL) allows for bipolar electrogram collection in both orthogonal and perpendicular planes, unique when compared to traditional and branch catheters. Experience in pediatric patients and congenital heart disease (CHD) is limited. The purpose of this work was to evaluate the utility and safety of the Advisor™ HD Grid mapping catheter in pediatric and CHD populations.

METHODS

Retrospective review of all pediatric patients and those with CHD (regardless of age) at Children's Hospital Colorado and University of Colorado undergoing electrophysiologic study in which the Advisor™ HD Grid mapping catheter was utilized.

RESULTS

Sixty-five procedures in 60 patients (N = 31 female (47.6%), median age 17 years (15-24.1)) were included. Patients had CHD in 30 procedures (46.1%). Eight-eight arrhythmia substrates were mapped including atrial flutter/intra-atrial reentrant tachycardia (N = 33), focal atrial tachycardia (N = 20), isolated PVCs (N = 10), accessory pathways (N = 9), atrioventricular nodal reentrant tachycardia (N = 7), right ventricular substrate mapping (N = 7), and ventricular tachycardia (N = 2). Median time per map was 11.8 (7.5-20.1) min with 3.2 (± 1.7) maps per procedure and a median of 2634 (1767-7654) points used per map. Patients with CHD required more maps (p < 0.001) and points per map (p < 0.001). Ablation was successful in 92.4% of procedures.

CONCLUSIONS

The Advisor™ HD Grid mapping catheter is safe and effective in the pediatric and congenital heart disease population. A wide variety of arrhythmia substrates can be mapped with high point density and low mapping time.

Omnipolar activation EGM to identify the earliest breakout site of atrial tachycardia

AT was mapped with Advisor HD Grid for earliest breakout site via local activation timing (LAT) map and Omnipolar map. While both maps point to earliest breakout site from low anterior right atrium, omnipolar map localised it to a more precise location compared to the earliest breakout site from LAT map. Ablation in this same spot rendered AT non inducible.

Koch's triangle voltage mapping for cryoablation of slow pathway in children: preliminary data of a novel high-density technique

PURPOSE

Different authors have described three-dimensional (3D) voltage mapping of the Koch's triangle (KT) in order to find low-voltage bridges (LVB) as targets for a successful transcatheter ablation (TCA) of the slow pathway (SP) in children. Recently, the Advisor High Density (HD) Grid™ mapping catheter was introduced as new multipolar catheter for HD mapping. The aim of the study was to describe our preliminary experience with the use of HD Grid™ catheter in LVB and electrophysiologically guided cryoablation of SP in children.

METHODS

Twenty-one children (mean age 13±3 years) with atrioventricular nodal re-entrant tachycardia (AVNRT) underwent cryoablation of SP guided by voltage HD mapping of the KT using HD Grid™ catheter. In order to better highlight the differences with conventional mapping, point collection was performed in each patient with this new multipolar catheter and with a quadripolar catheter.

RESULTS

The conventional mapping collected 871±262 points and used 211±80 points in 887±275 s, whereas HD mapping collected 7468±2947 points, using 604±165 points in 513±181 s (p<0.001). Moreover, the LVB area mapped with HD Grid™ was about one-half smaller and clearly delineated. Cryoablation acute success rate was 100%. Overall median fluoroscopy exposure was 0.08 (0.01-5.42) μGy/m2, with a median fluoroscopy time of 0.1 (0.0-0.6) min. During the follow-up (4.8 ± 3.7 months), there were no recurrences. No complications occurred.

CONCLUSIONS

Our preliminary experience shows that HD mapping is faster and offers higher spatial resolution and definition. Procedural time can be reduced maintaining the TCA safe, with reduced fluoroscopy use and success.

Next-generation mapping with HD Grid and HD Wave

High-definition (HD) mapping with the Advisor HD Grid and HD Wave Solution software offers unparalleled resolution in mapping complex arrhythmias. The unique shape of a HD Grid (16 electrodes in a 4 × 4 pattern) allows for the mapping of orthogonal electrograms (EGMs). In so doing, the HD Grid catheter virtually eliminates the issue of 'bipolar blindness', a phenomenon seen when a wavefront of propagation is traveling perpendicular to a bipole pair. By improving the accuracy of the 3D electroanatomical map, HD Grid offers the potential of shorter procedure times, safer ablations and higher success rates. The following article explores the role of HD Grid in mapping a variety of arrhythmias including supraventricular tachycardias, atrial fibrillation and ventricular tachycardia. In addition, the authors explore the role of HD Grid in more recently described substrate-based advanced mapping techniques.

Quantitative evaluation of different high-density 3D mapping modes for atrial and ventricular substrate assessment of cardiac arrhythmias with the HD grid catheter

BACKGROUND

Atrial and ventricular arrhythmias significantly contribute to morbidity and mortality of patients with cardiac disease. Ablation of these arrhythmias has shown to improve clinical outcomes, yet targeted ablation strategies rely on proper mapping capabilities. In the present study, we compare different modes of high-resolution mapping in clinically relevant arrhythmias using HD grid.

METHODS AND RESULTS

Using the Advisor™ HD Grid Mapping Catheter in either the standard, the wave (bipolar along spline and bipolar orthogonal) or the wave diagonal setting, low-voltage areas were determined. Low-voltage was defined as local electrograms with an amplitude <0.5 mV (bipolar; atria/ventricle) or <4 mV (unipolar; ventricle). Ultra high-density mapping in 47 patients with ventricular tachycardia, ventricular premature beats, atrial fibrillation and atrial tachycardia provided reliable information for the understanding of the arrhythmia mechanism resulting in safe ablation procedures. Regions of low voltage were significantly decreased by 14 ± 2% and 31 ± 3% with wave and wave diagonal settings as compared to standard settings, respectively.

CONCLUSION

Substrate mapping and risk stratification relies on proper low voltage discrimination. Even though the Advisor™ HD Grid Mapping Catheter was safely used in all cases, the extent of low voltage areas was mapping-mode dependent.

Confirmation of Pulmonary Vein Isolation with High-Density Mapping: Comparison to Traditional Workflows

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Yet tools and techniques used for confirmation of PVI vary greatly, and it is unclear whether the use of any particular combination of tools and techniques provides greater sensitivity for identifying gaps periprocedurally. It has been suggested the use of a high-density mapping catheter, which enables simultaneous recording of adjacent bipolar EGMs in two directions, may provide improved sensitivity for gap identification. Anonymized, acute procedural data was prospectively collected in AF ablation cases utilizing various workflows for confirmation of PVI. Post-hoc analysis was performed to evaluate the incidence of gaps detected by different diagnostic catheter technologies, including a high-density mapping catheter and circular mapping catheters (CMCs), and common techniques such as pacing the ablation lines. A total of 139 cases were included across three subgroup analyses: 99 cases were included in an indirect comparison of three mapping catheter technologies, revealing gaps in 36.7%, 38.9%, and 81.8% of cases utilizing a 10-pole CMC, 20-pole CMC, and a high-density mapping catheter, respectively; a direct comparison of diagnostic catheter technologies in 18 cryoballoon ablation cases revealed residual gaps in 22.2% of patients identified by high-density mapping which were missed previously with the use of a 3.3F CMC; in 22 cases utilizing a technique of pacing the ablation lines, high-density mapping identified residual gaps in 68.2% of patients. This proof of concept analysis demonstrated that the use of a high-density catheter which records orthogonal bipoles simultaneously, appears to improve acute detection of gaps in PVI lines relative to other commonly utilized techniques and technologies. The long-term impact of ablating these concealed gaps remains unclear. Further study, including direct comparison of diagnostic catheter technologies in a randomized setting with long-term followup, is warranted.

Utility of directional high-density mapping catheter (AdvisorTM HD Grid) in complex scar-related atrial tachycardia

Mapping of scar-related atrial tachycardias (AT) can be challenging even with the use of high-density (HD) mapping catheter. AdvisorTM HD Grid is the only directional HD mapping catheter which not only identify local electrical signal but more importantly capture the direction of wave front propagation especially in low voltage zone. Accordingly, we present a case of complex scar-related AT with the use of AdvisorTM HD Grid which showed clear fractionated signal at isthmus area as compare to the absence of signal on ablation catheter at the same area despite adequate contact force. Ablation at this area terminated the tachycardia.

Identifying a Gap in a Cavotricuspid Isthmus Flutter Line Using the Advisor™ HD Grid High-Density Mapping Catheter

This report discusses the mapping of an incomplete cavotricuspid isthmus flutter line with a high-density mapping catheter to visualize the arrhythmogenic substrate responsible for incomplete block. The relevant signals were unapparent when using a traditional ablation catheter but were evident with application of a high-density mapping catheter. High-density mapping holds promise for recording electrograms in gaps in other ablation lesion sets that may not be able to be easily identified using more traditional equipment alone.

Left atrial voltage mapping with a direction-independent grid catheter: Comparison with a conventional circular mapping catheter

INTRODUCTION

A recently introduced grid mapping catheter (GMC) is designed for better electrode-tissue contact and can collect bipolar signals both along and across the splines, which may allow more efficient voltage map generation independent of propagation direction. We compared the GMC with a conventional circular mapping catheter (CMC) for left atrial (LA) voltage mapping.

METHODS

This study included 20 consecutive patients undergoing repeat ablation for recurrent atrial fibrillation who had demonstrated LA low-voltage areas (LVAs, <0.10 mV). Following pulmonary vein isolation, LA voltage mapping was performed twice, once using the GMC and once using the CMC.

RESULTS

Voltage mapping was more efficient using the GMC than the CMC in terms of mapping time (459 [404, 543] vs 602 [496, 814] seconds; P = .014) and the number of mapping points (2446 [2099, 3104] vs 1841 [1494, 2314]; P = .002). The incidence of catheter-induced ectopies was lower (44 [28, 62] vs 114 [74, 188]; P < .0001) using the GMC. The GMC utilizing all bipoles detected LVAs in 85% of patients with LVAs detected by CMC. LVA measurements were significantly smaller on maps generated by the GMC using bipoles along or across the splines than those measured with the CMC (11.1 [4.6, 17.2] or 9.7 [2.5, 16.0] vs 16.4 [6.8, 26.8] cm² ; P = .008 and P = .001, respectively), and were even smaller when using all bipoles (7.9 [1.1, 13.5] cm² , P = .0001).

CONCLUSION

The GMC allowed a more efficient mapping procedure and enabled more selective identification of LVAs with smaller LVA size.

Enhanced ventricular tachycardia substrate resolution with a novel omnipolar high-density mapping catheter: the omnimapping study

BACKGROUND

Defining diastolic slow-conduction channels within the borderzone (BZ) of scar-dependent re-entrant ventricular tachycardia (VT) is key for effective mapping and ablation strategies. Understanding wavefront propagation is driving advances in high-density (HD) mapping. The newly developed Advisor™ HD Grid Mapping Catheter (HD GRID) has equidistant spacing of 16, 1 mm electrodes in a 4 × 4 3 mm interspaced arrangement allowing bipolar recordings along and uniquely across the splines (orthogonal vector) to facilitate substrate mapping in a WAVE configuration (WAVE). The purpose of this study was to determine the relative importance of the WAVE configuration compared to the STANDARD linear-only bipolar configuration (STANDARD) in defining VT substrate.

METHODS

Thirteen patients underwent VT ablation at our institution. In all cases, a substrate map was constructed with the HD GRID in the WAVE configuration (conWAVE) to guide ablation strategy. At the end of the procedure, the voltage map was remapped in the STANDARD configuration (conSTANDARD) using the turbo-map function. Detailed post-hoc analysis of the WAVE and STANDARD maps was performed blinded to the configuration. Quantification of total scar area, BZ and dense scar area with assessment of conduction channels (CC) was performed.

RESULTS

The substrate maps conSTANDARD vs conWAVE showed statistically significant differences in the total scar area (56 ± 32 cm² vs 51 ± 30 cm²; p = 0.035), dense scar area (36 ± 25 cm² vs 29 ± 22 cm²; p = 0.002) and number of CC (3.3 ± 1.6 vs 4.8 ± 2.5; p = 0.026). conWAVE collected more points than the conSTANDARD settings (p = 0.001); however, it used fewer points in map construction (p = 0.023).

CONCLUSIONS

The multipolar Advisor™ HD Grid Mapping Catheter in conWAVE provides more efficient point acquisition and greater VT substrate definition of the borderzone particularly at the low-voltage range compared to conSTANDARD. This greater resolution within the low-voltage range facilitated CC definition and quantification within the scar, which is essential in guiding the ablation strategy.