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