Multimodal Examination of Atrial Fibrillation Substrate: Correlation of Left Atrial Bipolar Voltage Using Multi-Electrode Fast Automated Mapping, Point-by-Point Mapping, and Magnetic Resonance Image Intensity Ratio.
Background
Bipolar voltage mapping, as part of atrial fibrillation (AF) ablation, is traditionally performed in a point-by-point (PBP) approach using single-tip ablation catheters. Alternative techniques for fibrosis-delineation include fast-anatomical mapping (FAM) with multi-electrode circular catheters, and late gadolinium-enhanced magnetic-resonance imaging (LGE-MRI). The correlation between PBP, FAM, and LGE-MRI fibrosis assessment is unknown.


Objective
In this study, we examined AF substrate using different modalities (PBP, FAM, and LGE-MRI mapping) in patients presenting for an AF ablation.


Methods
LGE-MRI was performed pre-ablation in 26 patients (73% males, age 63±8years). Local image-intensity ratio (IIR) was used to normalize myocardial intensities. PBP- and FAM-voltage maps were acquired, in sinus rhythm, prior to ablation and co-registered to LGE-MRI.


Results
Mean bipolar voltage for all 19,087 FAM voltage points was 0.88±1.27mV and average IIR was 1.08±0.18. In an adjusted mixed-effects model, each unit increase in local IIR was associated with 57% decrease in bipolar voltage (p<0.0001). IIR of >0.74 corresponded to bipolar voltage <0.5 mV. A total of 1554 PBP-mapping points were matched to the nearest FAM-point. In an adjusted mixed-effects model, log-FAM bipolar voltage was significantly associated with log-PBP bipolar voltage (ß=0.36, p<0.0001). At low-voltages, FAM-mapping distribution was shifted to the left compared to PBP-mapping; at intermediate voltages, FAM and PBP voltages were overlapping; and at high voltages, FAM exceeded PBP-voltages.


Conclusion
LGE-MRI, FAM and PBP-mapping show good correlation in delineating electro-anatomical AF substrate. Each approach has fundamental technical characteristics, the awareness of which allows proper assessment of atrial fibrosis.
['Zghaib|Tarek|T|', 'Keramati|Ali|A|', 'Chrispin|Jonathan|J|', 'Huang|Dong|D|', 'Balouch|Muhammad A|MA|', 'Ciuffo|Luisa|L|', 'Berger|Ronald D|RD|', 'Marine|Joseph E|JE|', 'Ashikaga|Hiroshi|H|', 'Calkins|Hugh|H|', 'Nazarian|Saman|S|', 'Spragg|David D|DD|']
D000368:Aged D001281:Atrial Fibrillation D017115:Catheter Ablation D022062:Electrophysiologic Techniques, Cardiac D005260:Female D006325:Heart Atria D006801:Humans D007090:Image Interpretation, Computer-Assisted D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D008955:Models, Cardiovascular D011446:Prospective Studies
Atrial Fibrillation Substrate Magnetic Resonance Imaging Voltage Mapping Fibrosis