High density evaluation of the arrhythmogenic substrate in atrial fibrillation (HEAT-AF)
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Type
Journal Article
Abstract
Background: Left atrial (LA) fibrosis is a key component of arrhythmogenic remodelling in atrial fibrillation (AF). LA low-voltage areas (LVAs) are considered surrogates for fibrosis and novel targets for ablation. However, there are no established criteria for identifying such potential pathogenic areas, particularly when utilising omnipolar mapping (OT).
Objective: To evaluate the correlation between OT and conventional bipolar voltage (BiV) in AF and regular rhythms.
Methods: Bipolar and OT mapping was performed in 17 patients undergoing de novo ablation for persistent AF. Mapping was performed in AF and coronary sinus pacing (CSP) at 600ms. BiV <0.5mV were defined as low voltage.
Results: LA voltage in AF correlated poorly with CSP using either BiV (r=0.15), or OT (r=0.16). OT yielded higher voltages than BiV in AF (0.62±0.24 vs. 0.49±0.18mV, p<0.050) and during CSP (1.85±0.78 vs. 1.60±0.80mV, p<0.050). LVA burden, as percentage of LA surface area, varied significantly depending on the atrial rhythm and mapping approach (AF bipolar: 65.0 ± 15.6%, AF OT: 56.2 ± 17.0%, CSP bipolar: 34.2±18.9%, CSP OT: 24.56±13.5%, p<0.050). BiV thresholds of 0.5mV during CSP and 0.3mV in AF corresponded to an OT voltage of 0.84mV and 0.40mV, respectively.
Conclusion: The mapping tool and atrial rhythm significantly influence LA voltage and LVA burden for both bipolar and OT mapping. Applying a universal bipolar or OT cut-off for low voltage in AF and sinus rhythm will not accurately reflect the arrhythmogenic substrate. OT yields higher voltage than corresponding bipolar measurements, thus adjustments in thresholds are required when using OT.
Objective: To evaluate the correlation between OT and conventional bipolar voltage (BiV) in AF and regular rhythms.
Methods: Bipolar and OT mapping was performed in 17 patients undergoing de novo ablation for persistent AF. Mapping was performed in AF and coronary sinus pacing (CSP) at 600ms. BiV <0.5mV were defined as low voltage.
Results: LA voltage in AF correlated poorly with CSP using either BiV (r=0.15), or OT (r=0.16). OT yielded higher voltages than BiV in AF (0.62±0.24 vs. 0.49±0.18mV, p<0.050) and during CSP (1.85±0.78 vs. 1.60±0.80mV, p<0.050). LVA burden, as percentage of LA surface area, varied significantly depending on the atrial rhythm and mapping approach (AF bipolar: 65.0 ± 15.6%, AF OT: 56.2 ± 17.0%, CSP bipolar: 34.2±18.9%, CSP OT: 24.56±13.5%, p<0.050). BiV thresholds of 0.5mV during CSP and 0.3mV in AF corresponded to an OT voltage of 0.84mV and 0.40mV, respectively.
Conclusion: The mapping tool and atrial rhythm significantly influence LA voltage and LVA burden for both bipolar and OT mapping. Applying a universal bipolar or OT cut-off for low voltage in AF and sinus rhythm will not accurately reflect the arrhythmogenic substrate. OT yields higher voltage than corresponding bipolar measurements, thus adjustments in thresholds are required when using OT.
Date Acceptance
2025-06-25
Citation
Heart Rhythm O2
ISSN
2666-5018
Publisher
Elsevier
Journal / Book Title
Heart Rhythm O2
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
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Publication Status
Accepted