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.

Abstract

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.

• Authors: Tarek Zghaib, Ali Keramati, Jonathan Chrispin, Dong Huang, Muhammad A Balouch, Luisa Ciuffo, Ronald D Berger, Joseph E Marine, Hiroshi Ashikaga, Hugh Calkins, Saman Nazarian, David D Spragg
• Journal: JACC. Clinical electrophysiology (JACC Clin Electrophysiol) Vol. 4 Issue 1 Pg. 59-68 (01 2018) ISSN: 2405-500X [Print] United States
• PMID: 29520376 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Topics

• Aged
• Atrial Fibrillation (diagnostic imaging, physiopathology, surgery)
• Catheter Ablation
• Electrophysiologic Techniques, Cardiac
• Female
• Heart Atria (diagnostic imaging, physiopathology)
• Humans
• Image Interpretation, Computer-Assisted
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Models, Cardiovascular
• Prospective Studies