AUTHOR=Ali Rheeda L. , Qureshi Norman A. , Liverani Silvia , Roney Caroline H. , Kim Steven , Lim P. Boon , Tweedy Jennifer H. , Cantwell Chris D. , Peters Nicholas S. 

TITLE=Left Atrial Enhancement Correlates With Myocardial Conduction Velocity in Patients With Persistent Atrial Fibrillation

JOURNAL=Frontiers in Physiology

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.570203

DOI=10.3389/fphys.2020.570203

ISSN=1664-042X

ABSTRACT=Background: Conduction velocity (CV) heterogeneity and myocardial fibrosis both promote re-entry, but the relationship between fibrosis as determined by left atrial (LA) late-gadolinium enhanced cardiac magnetic resonance imaging (LGE-CMRI) and CV remains uncertain.  
Objective: Although average CV has been shown to correlate with regional LGE-CMRI in patients with persistent AF, we test the hypothesis that a localized relationship exists to underpin LGE-CMRI as a minimally invasive tool to map myocardial conduction properties for risk stratification and treatment guidance.
Method: 3D LA electroanatomic maps during LA pacing were acquired from eight patients with persistent AF following electrical cardioversion. Local CVs were computed using triads of concurrently acquired electrograms and were co-registered to allow correlation with LA wall intensities obtained from LGE-CMRI, quantified using normalized intensity (NI) and image intensity ratio (IIR). Association was evaluated using multilevel linear regression.
Results: An association between CV and LGE-CMRI intensity was observed at scales comparable to the size of a mapping electrode:-0.11m/s per unit increase in NI (P<0.001) and -0.96m/s per unit increase in IIR (P<0.001). The magnitude of this change decreased with larger measurement area. Reproducibility of the association was observed with NI, but not with IIR.
Conclusion: At clinically relevant spatial scales, comparable to the area of a mapping catheter electrode, LGE-CMRI correlates with CV. The measurement scale is important in accurately quantifying the association of CV and LGE-CMRI intensity. Importantly, NI, but not IIR, account for changes in the dynamic range of CMRI and enables the quantitative reproducibility of the association.