Association of Left Atrial Local Conduction Velocity With Late Gadolinium Enhancement on Cardiac Magnetic Resonance in Patients With Atrial Fibrillation

Abstract

Background Prior studies have demonstrated regional left atrial late gadolinium enhancement (LGE) heterogeneity on magnetic resonance imaging. Heterogeneity in regional conduction velocities is a critical substrate for functional reentry. We sought to examine the association between left atrial conduction velocity and LGE in patients with atrial fibrillation (AF). Methods and Results LGE imaging and left atrial activation mapping were performed during sinus rhythm in 22 patients prior to pulmonary vein isolation. The locations of 1468 electroanatomic map points were registered to the corresponding anatomic sites on 469 axial LGE image planes. The local conduction velocity at each point was calculated using previously established methods. The myocardial wall thickness and image intensity ratio (IIR) defined as left atrial myocardial LGE signal intensity divided by the mean left atrial blood pool intensity was calculated for each mapping site. The local conduction velocity and IIR in the left atrium (mean ± standard deviation) were 0.98±0.46 m/sec and 0.95±0.26, respectively. In multivariable regression analysis, clustered by patient, and adjusting for left atrial wall thickness, conduction velocity was associated with the local IIR (0.20 m/sec decrease in conduction velocity per increase in unit IIR, P<0.001). Conclusions In this clinical in vivo study we demonstrate that left atrial myocardium with increased gadolinium uptake has lower local conduction velocity. Identification of such regions may facilitate the targeting of the substrate for reentrant arrhythmias.

The importance of integrated left atrial evaluation: From hypertension to heart failure with preserved ejection fraction

“…Chronically elevated LA volumes and decreased LA emptying fractions lead to structural changes in the left atrium; the progression of LA remodelling is independently associated with the incidence of AF in asymptomatic subjects . Recent studies have demonstrated the utility of CMR LGE to detect abnormal atrial tissue before catheter ablation; LA myocardium with increased LGE signal has lower local conduction velocity, and the identification of such regions may facilitate targeting of the substrate for re‐entrant arrhythmias . In recent years, CCT has emerged as a new technique to evaluate LA anatomy.…”

“…17 Recent studies have demonstrated the utility of CMR LGE to detect abnormal atrial tissue before catheter ablation; LA myocardium with increased LGE signal has lower local conduction velocity, and the identification of such regions may facilitate targeting of the substrate for re-entrant arrhythmias. [18][19][20] In recent years, CCT has emerged as a new technique to evaluate LA anatomy. It is the preferred tool to assess pulmonary vein anatomy, and it provides a real anatomical roadmap of left atrium before and…”

Characteristics of Residual Atrial Posterior Wall and Roof‐Dependent Atrial Tachycardias after Pulmonary Vein Isolation

“…Many reports could demonstrate that the atrial volume predicts the outcome of AF . A large left atrial volume might imply the progression of the arrhythmogenic substrates, including low‐voltage areas, multiple arrhythmogenic triggers, and a lower local conduction velocity in an enlarged and remodeled LA . We speculated that the remodeling‐induced atrial dilation could promote macro‐reentrant ATs by both increasing the circuit space and reducing the conduction velocity so that larger reentry circuits could be maintained.…”

Clinical impact of insulin resistance on pulmonary vein isolation outcome in patients with paroxysmal atrial fibrillation

“…Local conduction velocity was determined in the direction of the propagation. The local conduction velocity for each point was calculated according to a previously established methodology from prior studies . The local conduction velocity was defined using electroanatomical mapping points as the average of the conduction velocity calculated by using five different adjacent point pairs along the activation front, where the conduction velocity between each pair of points was defined as the linear distance between the points divided by the difference in activation times.…”

“…The local conduction velocity for each point was calculated according to a previously established methodology from prior studies. [16][17][18][19] The local conduction velocity was defined using electroanatomical mapping points as the average of the conduction velocity calculated by using five different adjacent point pairs along the activation front, where the conduction velocity between each pair of points was defined as the linear distance between the points divided by the difference in activation times. To avoid the inclusion of conduction velocity measurements in a different direction than that of activation propagation, points with a difference in local activation time of <5 ms from the index point were excluded from the conduction velocity calculation for that index point.…”