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High-Throughput Analysis of Optical Mapping Data Using ElectroMap
Published on: June 4, 2019
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Detailed analysis of electrogram peak frequency to guide ventricular tachycardia substrate mapping
Joseph Mayer1,2, Jaffar Al-Sheikhli1,3, Maria Niespialowska-Steuden1
1Department of Cardiology, University Hospital Coventry and Warwickshire NHS Trust, CV2 2DX Coventry, UK.
Summary
Low-voltage area peak frequency mapping effectively identifies critical components of ventricular tachycardia circuits. An optimal threshold of ≥200 Hz aids in VT ablation success.
Area of Science:
- Electrophysiology
- Cardiac Arrhythmias
- Signal Processing
Background:
- Differentiating near-field (NF) and far-field (FF) electrograms (EGMs) is crucial for identifying critical arrhythmogenic substrate during ventricular tachycardia (VT) ablation.
- Novel algorithms can annotate NF-fractionated signals and determine EGM peak frequency (PF) using wavelet transformation.
Purpose of the Study:
- To evaluate the effectiveness of a novel algorithm in identifying critical components of the VT circuit during substrate mapping.
- To assess the diagnostic performance of low-voltage area (LVA) PF substrate mapping for VT ablation.
Main Methods:
- Investigated a multicentre, international cohort undergoing VT ablation, using VT activation maps to demarcate the isthmus zone (IZ).
- Performed offline analysis to evaluate LVA PF substrate mapping diagnostic performance.
- Included 30 patients and 198,935 EGMs, analyzing PF in sinus rhythm (SR) and right ventricular paced (RVp) conditions.
Main Results:
- Isthmus zone (IZ) PF was significantly higher in SR compared to RVp substrate maps (234 Hz vs. 197 Hz; P = 0.010).
- IZ PF was significantly higher than LVA PF in both SR and RVp maps (AUC: 0.74 and 0.70, respectively).
- An LVA PF threshold of ≥200 Hz was optimal for identifying the VT isthmus in SR and RVp maps (sensitivity 60-69%; specificity 64%).
- In amiodarone-treated patients, SR substrate map IZ PF was significantly lower compared to amiodarone-naïve patients (222 Hz vs. 303 Hz; P = 0.009).
- The ≥200 Hz LVA PF threshold correlated with 80% freedom from VT, with trends towards reduced ablation lesions and radiofrequency times.
Conclusions:
- Low-voltage area (LVA) PF substrate mapping effectively identifies critical components of the VT circuit with an optimal threshold of ≥200 Hz.
- Isthmus PF is influenced by chronic amiodarone therapy and is lower during RV pacing.
- This mapping approach shows promise for improving VT ablation outcomes.
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