Low voltage zones detected by omnipolar Vmax map accurately identifies the potential atrial substrate and predicts the AF ablation outcome after PV isolation

https://doi.org/10.1016/j.ijcard.2021.12.037Get rights and content

Highlights

  • The presence of bipolar low-voltage zone is a predictor of AF recurrence after pulmonary vein isolation.

  • Changes of wavefront and bipole directions may cause different electrogram characteristics.

  • The wavefront orientation-optimized voltage map by omnipolar technology may define the left atrium substrate more accurately.

Abstract

Introduction

The presence of bipolar low-voltage zone (LVZ) is a predictor of AF recurrence after PV isolation (PVI). However, changes of wavefront and bipole directions may cause different electrogram characteristics. We aimed to investigate whether using omnipolar maximum voltage (Vmax) map derived from high density (HD) Grid mapping catheter could assess LVZ and AF ablation outcome accurately.

Methods

Fifty paroxysmal AF patients (27 males, 57.8 ± 9.5 years old) who underwent 3D mapping guided PVI were enrolled. Left atrial voltage mapping during sinus rhythm before ablation was performed. The significant LVZ (<0.5 mV with area > 5 cm2) were defined as sites by omnipolar Vmax, bipolar HD wave map, conventional bipolar electrograms acquired from electrode pairs along to and across to the catheter shaft. The primary end point was the first documented recurrence of any AF during follow-ups.

Results

PVI was performed in all patients, and there were 2 patients (4%) who also received additional non-PV triggers ablation. After a follow-up of 11.4 ± 5.4 months, recurrence of AF occurred in 12 patients (24%). The presence of a significant LVZ was less detected by omnipolar Vmax map, compared to HD wave map (24.0% vs. 58.0%, p = 0.001). LVZ detected by omnipolar Vmax map independently predicted the AF recurrence (odds ratio 16.91; 95% CI, 3.17–90.10; p = 0.001).

Conclusion

LVZ detected by omnipolar Vmax map accurately predicts the AF recurrence following ablation in paroxysmal AF, compared to conventional bipolar and HD wave maps, suggesting the omnipolar Vmax map can precisely define the atrial substrate property.

Introduction

Catheter ablation is an established treatment for patients with drug-refractory atrial fibrillation (AF), and pulmonary vein isolation (PVI) is the cornerstone for AF ablation [1]. Apart from pulmonary vein reconnection, abnormal atrial substrate also contributes to AF recurrences after PVI [2]. Apart from persistent AF [[3], [4], [5], [6], [7]], recent studies also demonstrated the presence of left atrial low-voltage zone (LVZ) as an independent predictor of AF recurrence in paroxysmal AF [[8], [9], [10], [11]]. However, the VOLCANO study found LVZ based ablation in addition to PVI had no benefit on rhythm outcomes, despite the presence of LVZ was a strong predictor of paroxysmal AF recurrence [10].

Wong et al. have reported the variation in cycle length and directions of wavefront activation resulting in the significant changes in substrate maps [12], which may raise a concern for the accuracy of ablation over the static LVZ. The omnipolar technology (OT), which yields a wavefront direction-independent, orientation-optimized maximum voltage (OT Vmax) map [13], may provide a potential solution.

Here, we aimed to compare the paroxysmal AF recurrence after PVI in patients with and without LVZ, detected by OT Vmax, bipolar high-density (HD) wave and conventional bipolar maps, respectively.

Section snippets

Patient selection

A total of 50 patients who received catheter ablation for drug-refractory, symptomatic paroxysmal AF, and without previous AF ablation or ablation in the LA were enrolled. Paroxysmal AF was defined as recurrent AF episodes that terminated spontaneously within 7 days. Clinical characteristics, co-morbidities and medications were determined according to medical records. The left atrial (LA) diameter was measured by echocardiography. The study complied with the Declaration of Helsinki, and the

Patient characteristics

The study population consisted of 50 patients with paroxysmal AF (27 males, 57.8 ± 9.5 years old). The clinical characteristics of the patients are summarized in Table 1. The mean LA dimension was 36.4 ± 5.1 mm, mean CHA2DS2-VASc score was 1.46 ± 1.20, and the mean follow-up was 11.4 ± 5.4 months.

Index procedure details

All patients received PVI with HPSD setting. The average procedural and fluoroscopy times were 272.6 ± 49.0 and 92.5 ± 42.0 min respectively. PVI was achieved successfully in all patients. Forty-two

Main findings

In the present study, we found that: (1) The LVZ detected from OT Vmax was less than that measured by bipolar HD wave or conventional bipolar voltage maps in patients with paroxysmal AF; (2) The LVZ detected by omnipolar technology was an independent factor for AF recurrence after an index PVI in paroxysmal AF. Those findings indicate that conventional bipolar voltage map may overestimate the diseased atrial substrate, whereas the OT Vmax can accurately identify the critical substrates that

Conclusions

LVZ yielded by OT Vmax accurately predicts the AF recurrence following PVI in paroxysmal AF, compared to the conventional bipolar and HD wave maps, respectively. OT Vmax can precisely define the atrial substrate properly and is expected to be better in predicting the clinical outcome and possibly provide an insight to the critical atrial substrate that maintaining AF beyond PVI in patients with paroxysmal AF.

Funding sources

The present work was supported by grants from the Taipei Veterans General Hospital (V109C-001, V109C-005, V110C-024, V110-014), the Ministry of Science and Technology (MOST108-2314-B-010-051-MY3, MOST108-2811-B-010-542, MOST109-811-B-010-529, MOST109-2314-B-075-075-MY3), and Abbott research grant.

Declaration of Competing Interest

None.

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