High-density mapping in patients undergoing ablation of atrial fibrillation with the fourth-generation cryoballoon and the new spiral mapping catheter

Analysis of the effectiveness of the latest 4th-generation cryoballoon catheters in pulmonary vein isolation using high-resolution mapping

BACKGROUND

Long-term data showed that up to 27% of pulmonary veins are reconnected using cryoballoon ablation. This study aimed to evaluate the efficacy of the latest 4th-generation cryoballoon catheters using ultra high-resolution mapping.

METHODS

In patients with atrial fibrillation, a standard pulmonary vein isolation (PVI) with the latest 4th-generation cryoballoon catheter (Arctic Front Advance PRO, Medtronic Minneapolis, USA) and the spiral mapping catheter (Achieve Advance, Medtronic, Minneapolis, MN, USA) was performed. Subsequently, high-resolution mapping was achieved using the novel multipolar grid mapping catheter (Advisor HD Grid SE, Abbott Laboratories, USA). Follow-up was obtained after 6 months by means of a 7-day Holter electrocardiogram.

RESULTS

In our study, acute PVI was successfully achieved in all 31 patients. The latest 4th-generation cryoballoon catheter is safe in the acute phase of PVI. Additional high-resolution mapping (mean points per map 21,001 ± 4911) using the multipolar grid mapping catheter enabled us to identify residual gaps only in the carina pulmonary vein region; therefore, no additional ablation was performed. Three of 31 patients (10%) presented with atrial arrhythmia recurrence always related with pulmonary vein reconnection; using high-resolution mapping had no additional benefit in identifying pulmonary veins in which reconnection will occur.

CONCLUSION

The utility of additional high-density mapping, facilitated by the HD Grid catheter after PVI with the 4th-generation cryoballoon catheter do not substantiate a discernible advantage over conventional mapping methodologies, particularly, the spiral mapping catheter. Residual carinal conduction was observed in a substantial cohort of patients (48%), highlighting a persistent challenge in achieving complete electrical isolation.

Use of the advisor™ HD Grid mapping catheter in transcatheter ablation of atrial arrhythmias in palliated CHD and children without CHD

OBJECTIVE

In this study, we describe our experience utilising Advisor™ High Density (HD) Grid mapping catheter in transcatheter ablation of intraatrial re-entrant and focal atrial tachycardias with or without CHD.

METHODS

Forty-five consecutive patients with intraatrial re-entrant and focal atrial tachycardia who underwent a transcatheter ablation procedure by using Advisor™ HD Grid mapping catheter and high-density mapping system in our hospital from January 2017 to January 2023 were included into the study.

RESULTS

The mean age of the patients was 14.2 ± 7.3 years (6-32 years), and the mean weight was 48.3 ± 16.2 kg (22-83 kg). Of the total 45 patients, 21 were intraatrial re-entrant tachycardia and 25 were focal atrial tachycardia. Of the 21 re-entrant circuits, 15 were classified as cavotricuspid isthmus-dependent and 5 were non-cavotricuspid isthmus-dependent. In one patient, two re-entrant circuits were identified. A transbaffle ablation was successfully performed from the left atrium in one patient. Of the 25 focal atrial tachycardia, 19 were from right atrium and 6 were from left atrium. A cryoablation was performed in only one patient and radiofrequency ablation in others. The mean procedure time was 180 ± 64 minutes. The mean follow-up period was 69.3 ± 35.3 months. Acute success was 95.5%. Recurrence was noted in two patients (4.4%).

CONCLUSION

Advisor™ HD Grid mapping catheter was found to be safe and achieved an acceptable success in transcatheter ablation of patients with intraatrial re-entrant tachycardia and focal atrial tachycardias.

The absence of real-time pulmonary vein isolation during cryoballoon ablation is associated with atrial fibrillation recurrence and pulmonary vein reconnection : Insights from the Middelheim-PVI Registry 2

BACKGROUND

Absence of real-time pulmonary vein (PV) isolation (PVI) occurring in 15-40% of PVs during cryoballoon ablation (CBA) of atrial fibrillation (AF) raises doubt about adequate PVI. Aim of the present study is to determine whether real-time PVI during CBA is predictive of long-term clinical outcome and durability of PVI.

METHODS

Eight hundred three AF patients (64 ± 10 years, 68% males) undergoing CBA were studied. The cohort was divided in 4 groups according to the number of PVs without real-time PVI: none (N = 252 [31.4%]), 1 (N = 255 [31.8%]), 2 (N = 159 [19.8%]), and 3-4 (N = 137 [17.1]).

RESULTS

At 3 years, 279 (34.7%) patients had recurrence of AF of which 188 underwent repeat ablation. A vein without real-time PVI was associated with AF recurrence (HR = 1.275; 95% CI 1.134-1.433; p < 0.01), independent of persistent AF type (HR = 2.075; 95% CI 1.584-2.738; p < 0.01), left atrial diameter (HR = 1.050; 95% CI 1.028-1.072; p < 0.01), and diagnosis-to-ablation time (HR = 1.002; 95% CI 1.000-1.005; p = 0.04). Highest success was achieved with present real-time PVI in all veins (77.4%), gradually decreasing per increasing number of absent real-time PVI: 66.3% for 1 vein, 58.5% for 2, and 48.9% for 3-4 veins (p < 0.001). At repeat ablation (N = 188), PV reconnection was seen in 99/430 (23.0%) versus 83/288 (28.8%) veins with and without real-time PVI, respectively (p = 0.08). Right inferior PVs (RIPVs) with real-time PVI were less reconnected than RIPVs without real-time PVI: 29.7% versus 43.7% (p = 0.047).

CONCLUSION

The absence of real-time PVI during CBA independently predicts AF recurrence with a 30% gradual decrease in outcome per increase in veins without real-time PVI. Real-time PVI is particularly important for the RIPV to achieve durable PVI.

Delineation of conduction gaps of linear lesions during atrial fibrillation ablation using ultra-high-density mapping

AIMS

Linear lesions are routinely created by radiofrequency catheter ablation. Unwanted electrical conduction gaps can be produced and are often difficult to ablate. This study aimed to clarify the characteristics of conduction gaps during atrial fibrillation ablation by analysing bidirectional activation maps using a high-density mapping system (RHYTHMIA).

METHODS AND RESULTS

This retrospective study included 31 patients who had conduction gaps along pulmonary vein (PV) isolation or box ablation lesions. Activation maps were sequentially created during pacing from the coronary sinus and PV to reveal the earliest activation site, defined by the entrance and exit. The locations, length between the entrance and exit (gap length), and direction were analysed. Thirty-four bidirectional activation maps were drawn: 21 were box isolation lesions (box group), and 13 were PV isolation lesions (PVI group). Among the box group, nine conduction gaps were present in the roof region and 12 in the bottom region, while nine in right PV and four in left PV among the PVI group. Gap lengths in the roof region were longer than those in the bottom region (26.8 ± 11.8 vs. 14.5 ± 9.8 mm; P = 0.022), while those in right PV tended to longer than those in left PV (28.0 ± 15.3 vs. 16.8 ± 8.0 mm, P = 0.201).

CONCLUSION

The entrances and exits of electrical conduction gaps were separated, especially in the roof region, indicating that epicardial conduction might contribute to gap formation. Identifying the bidirectional conduction gap might indicate the location and direction of epicardial conduction.

Ultra-high-resolution assessment of lesion extension after cryoballoon ablation for pulmonary vein isolation

INTRODUCTION

Unrecognized incomplete pulmonary vein (PV) isolation during the index procedure, can be a major cause of clinical recurrences of atrial fibrillation (AF) after cryoballoon (CB) ablation. We aimed to characterize the extension of the lesions produced by CB ablation and to assess the value of using an ultra-high resolution electroanatomic mapping (UHDM) system to detect incomplete CB lesions.

MATERIALS AND METHODS

Twenty-nine consecutive patients from the CHARISMA registry undergoing AF ablation at four Italian centers were prospectively evaluated. The Rhythmia™ mapping system and the Orion™ (Boston Scientific) mapping catheter were used to systematically map the left atrium and PVs before and after cryoablation.

RESULTS

A total of 116 PVs were targeted and isolated. Quantitative assessment of the lesions revealed a significant reduction of the antral surface area of the PV, resulting in an ablated area of 5.7 ± 0.7 cm2 and 5.1 ± 0.8 cm2 for the left PV pair and right PV pair, respectively (p = 0.0068). The mean posterior wall (PW) area was 22.9 ± 2 cm2 and, following PV isolation, 44.8 ± 6% of the PW area was ablated. After CB ablation, complete isolation of each PV was documented by the POLARMap™ catheter in all patients. By contrast, confirmatory UHDM and the Lumipoint™ tool unveiled PV signals in 1 out of 114 of the PVs (0.9%). Over 30-day follow-up, no major procedure-related adverse events were reported. After a mean follow-up of 333 days, 89.7% of patients were free from arrhythmia recurrence.

CONCLUSION

The lesion extension achieved by the new CB ablation system involved the PV antrum, with less than 50% of the PW remaining untouched. The new system, with short tip and circular mapping catheter, failed to achieve PV isolation in only 0.9% of all PVs treated.

CLINICAL TRIAL REGISTRATION

[http://clinicaltrials.gov/], identifier [NCT03793998].