Key result
Optimized AF voltage threshold yields ~69% accuracy for identifying sinus rhythm low voltage substrate.
Why the study?
It is not clear how the location and extent of low voltage substrate correlate between electroanatomical mapping in sinus rhythm and AF.
What are the optimal regional voltage thresholds during atrial fibrillation to accurately identify low voltage substrate mapped during sinus rhythm?
Observational (n=41)
No
What are the optimal regional voltage thresholds during atrial fibrillation to accurately identify low voltage substrate mapped during sinus rhythm?
Specific regional voltage thresholds during atrial fibrillation can accurately identify low voltage substrate mapped during sinus rhythm, facilitating substrate-based ablation irrespective of the underlying rhythm.
Answers are grounded in this paper and cite their sources.
AF voltage thresholds may aid LVS identification irrespective of rhythm; leaves open prospective validation before guiding ablation.
Background Low voltage substrate (LVS) identified during electroanatomical mapping is a potential target for atrial fibrillation (AF) ablation. However, it is not clear how the location and extent of LVS correlate between mapping in sinus rhythm (SR) and AF. Objectives (1) Identify voltage dissimilarities between mapping in SR and AF. (2) Identification of regional voltage thresholds that improve cross-rhythm sub-strate detection. (3) Comparison of LVS between SR and native vs. induced AF. Methods Forty-one ablation-naive persistent AF patients underwent high-density voltage mapping in SR and AF. Each patient’s voltage information was mapped to a joint geometry for analysis. Global and regional voltage thresholds in AF were identified which best match LVS<0.5mV and <1.0mV in SR. Additionally, the correlation between SR-LVS with induced vs. native AF LVS was assessed. Results Substantial voltage differences (median: 0.52, IQR: 0.33-0.69, max: 1.19mV) with predominance of the posterior/inferior LA wall exist between the rhythms. An AF threshold of 0.34mV for the entire atrium provides an accuracy, sensitivity and specificity of 69%, 67% and 69% to identify SR-LVS<0.5mV, respectively. Lower thresholds for the posterior wall (0.27 mV) and inferior wall (0.3mV) result in higher spatial concordance to SR-LVS (4% and 7% increase). Concordance with SR-LVS was higher for induced AF compared to native AF (AUC: 0.80 vs. 0.73). AF-LVS<0.5mV corresponds to SR-LVS<0.97mV using high-definition mapping (AUC: 0.73). Conclusion The proposed voltage thresholds during AF maximise the consistency of LVS identification as determined during SR. Regional thresholds can further improve concordance.
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Nairn et al. (2022) conducted an observational in Persistent atrial fibrillation (n=41). Voltage mapping during atrial fibrillation vs. Voltage mapping during sinus rhythm was evaluated on Optimal AF voltage threshold to identify SR-LVS <0.5 mV. An atrial fibrillation voltage threshold of 0.34 mV provides 69% accuracy, 67% sensitivity, and 69% specificity for identifying low voltage substrate defined as <0.5 mV in sinus rhythm.
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