Prospective evaluation of a novel catheter equipped with mini electrodes on a 10-mm tip for cavotricuspid isthmus ablation - The efficacy of a mini electrode guided ablation

Ablation of CTI-dependent flutter using different ablation technologies: acute and long-term outcome from the LEONARDO study

BACKGROUND

A novel ablation catheter has been released to map and ablate the cavo-tricuspid isthmus (CTI) in patients with atrial flutter (AFL), improving ablation efficiency.

METHODS

We evaluated the acute and long-term outcome of CTI ablation aiming at bidirectional conduction block (BDB) in a prospective, multicenter cohort study enrolling 500 patients indicated for typical AFL ablation. Patients were grouped on the basis of the AFL ablation method (linear anatomical approach, Conv group n = 425, or maximum voltage guided, MVG group, n = 75) and ablation catheter (mini-electrodes technology, MiFi group, n = 254, or a standard 8-mm ablation catheter, BLZ group, n = 246).

RESULTS

Complete BDB according to both validation criteria (sequential detailed activation mapping or mapping only the ablation site) was achieved in 443 patients (88.6%). The number of RF applications needed to achieve BDB was lower in the MiFi MVG group vs both the MiFi Conv group and the BLZ Conv group (3.2 ± 2 vs 5.2 ± 4 vs 9.3 ± 5, p < 0.0001 for all comparisons). Fluoroscopy time was similar among groups, whereas we observed a reduction in the procedure duration from the BLZ Conv group (61.9 ± 26min) to the MiFi MVG group (50.6 ± 17min, p = 0.048). During a mean follow-up of 548 ± 304 days, 32 (6.2%) patients suffered an AFL recurrence. No differences were found according to BDB achieved by both validation criteria.

CONCLUSIONS

Ablation was highly effective in achieving acute CTI BDB and long-term arrhythmia freedom irrespective of the ablation strategy or the validation criteria for CTI chosen by the operator. The use of an ablation catheter equipped with mini-electrodes technology seems to improve ablation efficiency.

CLINICAL TRIAL REGISTRATION

Atrial Flutter Ablation in a Real World Population. (LEONARDO).

CLINICALTRIALS

gov Identifier: NCT02591875.

The advantage of mini electrode-equipped catheter for the radiofrequency ablation of paroxysmal supraventricular tachycardia

INTRODUCTION

Novel ablation catheters equipped with mini-electrodes (ME) offer high resolution mapping for target tissue. This study aimed to evaluate the mapping performance and efficacy of ME catheters in radiofrequency ablation (RFA) of paroxysmal supraventricular tachycardias (PSVTs).

METHODS

We prospectively enrolled 136 patients undergoing RFA of PSVT including 76 patients with atrioventricular nodal reentrant tachycardia (AVNRT) and 60 patients with atrioventricular reentrant tachycardia (AVRT) or Wolff-Parkinson-White (WPW) syndrome. Patients were randomized to the ME group (ablation using ME catheters) or the control group (ablation using conventional catheters). The number of ablation attempt and cumulative ablation time to ablation endpoints, which was defined as an emergence of junctional rhythm in AVNRT or accessory pathway (AP) block in AVRT/WPW syndromes were compared.

RESULTS

During ablation procedures, discrete slow pathway or AP electrograms were found in 27 (39.7%) patients in the ME group and 13 (19.1%) patients in the control group. The primary study outcomes were significantly lower in the ME group (ablation attempt number: 2.0 [1-4] vs. 3.0 [2-7] in the ME and control group, p=0.032; ablation time: 23.5 [5.0-111.5] vs. 64.5 [16.0-185.0] seconds, p=0.013). According to the PSVT diagnosis, ablation time to junctional rhythm was significantly shorter in the ME group in AVNRT. In AVRT/WPW syndrome, both ablation attempt number and ablation time to AP block were non-significantly lower in the ME group.

CONCLUSION

The novel ME catheter was advantageous for identifying pathway potentials and reducing initial ablation attempt number and ablation time to reach acute ablation endpoint for PSVTs. (ClinicalTrials.gov number, NCT04215640) This article is protected by copyright. All rights reserved.

The Mini Electrode-equipped Catheter: Utility for Paroxysmal Supraventricular Tachycardia Ablation

The role of catheter ablation for paroxysmal supraventricular arrhythmias (PSVT) is well established given that it is often a simple, safe, and successful procedure. This article is protected by copyright. All rights reserved.

Ablation of typical atrial flutter using mini electrode measurements for maximum voltage‐guided ablation: A randomized, controlled trial

Background

Novel ablation catheters with mini electrode (ME) sensing have become available but their utility is unclear. We investigated whether ablation of the cavotricuspid isthmus (CTI) for atrial flutter (AFL) would be improved using ME signals.

Methods

Sixty‐one patients (76% male, 63 ± 10 years) with CTI‐dependent AFL underwent ablation using a maximum voltage‐guided approach, randomized to either standard 8 mm non‐irrigated catheter with bipolar signals or IntellaTip MiFi catheter using ME signals alone.

Results

Acute bidirectional block was achieved in 97%. Mean follow‐up was 16.7 ± 10 months. The median number of ablation lesions was 13 in both groups (range 3–62 vs. 1–43, p = .85). No significant differences were observed in AFL recurrences (17% vs. 11%, p = .7), median procedure durations (97 min [interquartile range (IQR), 71–121] vs. 87 min [IQR, 72–107], p = .55) or fluoroscopy times (31 min [IQR, 21–52] vs. 38 min [IQR, 25–70], p = .56). Amplitudes of ME signals were on average 160% greater than blinded bipolar signals. In 23.7% of lesions where bipolar signals were difficult to interpret, 13.6% showed a clear ME signal.

Conclusions

There was no difference in the effectiveness of CTI ablation guided by ME signals, compared with using bipolar signals from a standard 8 mm ablation catheter. While ME signal amplitudes were larger and sometimes present when the bipolar signal was unclear, this did not improve procedural characteristics or outcomes. The results suggest future research should focus on lesion integrity rather than signal sensing.

Minielectrode catheter technology for near zero-fluoroscopy substrate-guided ablation of typical atrial flutter

Background

MicroFidelity catheter technology may facilitate voltage-guided ablation by high-resolution electroanatomic mapping (HR-EAM) and precisely targeted energy application.

Objective

To evaluate the performance of minielectrode (ME) technology for zero-fluoroscopy substrate-guided cavotricuspid isthmus (CTI) ablation.

Methods

Eighty-two patients underwent near zero-fluoroscopy substrate-guided CTI ablation using a nonirrigated large-tip catheter with 3 MEs. The CTI was subdivided into 15 electroanatomic segments. Bipolar voltage maps were compared with ME signals. The outcome was compared with a historic cohort of 92 patients who underwent linear ablation.

Results

Compared with linear ablation, the substrate-guided approach was associated with an almost halved ablation duration (336 ± 228 vs 649 ± 409 seconds, P < .001), halved radiofrequency energy applied (14.2 ± 10.6 vs 28.6 ± 19.6 kJ, P < .001), and shorter procedure duration (60.8 ± 33.8 vs 76.3 ± 40.9 minutes, P = .008) limiting the extent of energy delivery to 22.7% of the CTI area. HR-EAM visualized 2.03 ± 0.88 conductive pathways with a diameter of 5.35 ± 1.98 mm. A higher number of ME-detected bundles and a larger channel diameter correlated with increased ablation requirements. In 97.6% of the voltage-guided and 88.0% of the linear procedures, fluoroscopy was not used.

Conclusion

HR-EAM-based substrate-guided CTI ablation may improve procedural outcome compared with the linear approach. Enhanced identification of discrete conductive pathways correlates with ablation efficacy. The electroanatomic subdivision of the CTI into 15 segments was feasible and may improve the understanding and comparability of anatomic variants and ablation results. Independent of the ablation strategy, modern EAM technology enables safe zero-fluoroscopy procedures in the majority of cases.

Additional Diagnostic value of Mini Electrodes in an 8-mm Tip in Cavotricuspid Isthmus Ablation

Background

Eight-mm ablation catheters are widely used in cavotricuspid isthmus ablation (CTI) for treatment of right sided atrial flutter. However a high success rate, these large ablation tips comes with adisadvantage of lower resolution of fractionated signals.

Purpose

The aim of this study was to evaluate the additional diagnostic value of the electrograms recordedfrom mini electrodes (MEs) in an 8-mm ablation catheter tip during CTI.

Methods

CTI-ablation procedures were compared retrospectively in two groups, namely, group A: the Abbott Safire 8-mm tip with a 3D mapping system (n =37) and group B: the Boston Scientific MiFi IntellaTip XP 8-mm tip without a 3D mapping system (n=13). We analyzedacute procedural success, ablation characteristics and recurrence rate at one-year follow-up. Electrograms from MEs were analyzedright before the onset of the critical ablation application that resulted in acute CTI-block. We determined whether these ME electrograms had additional diagnostic value in addition to of the 8-mm tip derivedelectrogram.

Results

At the onset of the critical ablation application, the MEs had an important additional value in 3 out of 13 cases as local signals were sensed on the MEs that were not recorded by the 8-mm tip electrode. In 2cases the ME did not show local electrogramsalthough the ablationwas still effective. Acute procedural and long-term success wereobserved in all patients. No differences were found in time to bidirectional block, procedure time or fluoroscopic exposure.

Conclusion

Our data show that signals recorded from the MEs had additional diagnostic value, but only in asmall percentage of the patients. We did not observe, although omitting 3D-mapping in the ME group, any differencebetween groups with regard to procedural or ablation characteristicsduring CTI-ablation.

The combination of electroanatomic mapping and minielectrodes in a series of cases of redo procedures

Background

In patients with supraventricular tachycardia, catheter ablation is an important treatment option. However, approximately one quarter of these patients remain symptomatic, so sustainable strategies for the treatment of those patients who do not benefit from the first catheter ablation are required.

Methods

In a series of redo procedures, we investigated the combined use of an electro-anatomic mapping system and an ablation catheter with mini-electrodes.

Results

Catheter ablation was successful in two patients with recurrent common type atrial flutter and one patient with recurrent ectopic atrial tachycardia. In a patient with recurrent perimitral flutter, the ablation procedure had to be stopped early, due to pericardial effusion.

Conclusion

The combination of electro-anatomic mapping and mini-electrodes might be useful, especially in the treatment of ectopic atrial tachycardias, but also in redo procedures of CTI ablations, that require not only the visualization of the tachycardia, but also the detection of a local focus or a local gap. For an optimal use of the ME ablation catheter, the generator settings should be evaluated in further studies.