Accuracy of left atrial fibrosis detection with cardiac magnetic resonance: correlation of late gadolinium enhancement with endocardial voltage and conduction velocity

Abstract

Aims Myocardial fibrosis is a hallmark of atrial fibrillation (AF) and its characterization could be used to guide ablation procedures. Late gadolinium enhanced-magnetic resonance imaging (LGE-MRI) detects areas of atrial fibrosis. However, its accuracy remains controversial. We aimed to analyse the accuracy of LGE-MRI to identify left atrial (LA) arrhythmogenic substrate by analysing voltage and conduction velocity at the areas of LGE. Methods and results Late gadolinium enhanced-magnetic resonance imaging was performed before ablation in 16 patients. Atrial wall intensity was normalized to blood pool and classified as healthy, interstitial fibrosis, and dense scar tissue depending of the resulting image intensity ratio. Bipolar voltage and local conduction velocity were measured in LA with high-density electroanatomic maps recorded in sinus rhythm and subsequently projected into the LGE-MRI. A semi-automatic, point-by-point correlation was made between LGE-MRI and electroanatomical mapping. Mean bipolar voltage and local velocity progressively decreased from healthy to interstitial fibrosis to scar. There was a significant negative correlation between LGE with voltage (r = −0.39, P < 0.001) and conduction velocity (r = −0.25, P < 0.001). In patients showing dilated atria (LA diameter ≥45 mm) the conduction velocity predictive capacity of LGE-MRI was weaker (r = −0.40 ± 0.09 vs. –0.20 ± 0.13, P = 0.02). Conclusions Areas with higher LGE show lower voltage and slower conduction in sinus rhythm. The enhancement intensity correlates with bipolar voltage and conduction velocity in a point-by-point analysis. The performance of LGE-MRI in assessing local velocity might be reduced in patients with dilated atria (LA diameter ≥45).

Circulating intermediate monocytes and atrial structural remodeling associated with atrial fibrillation recurrence after catheter ablation

“…The authors speculated that far‐field potentials might conceal small local electrograms. Therefore, atrial fibrosis might remain undetected by conventional electroanatomical mapping, and LGE‐MRI might be a more sensitive technique than SR bipolar voltage to characterize atrial fibrosis 19 . Although the data were not shown, the distribution of the low‐voltage area, defined as an atrial voltage less than 0.5 mV, in the SR was not completely consistent with that of the LGE.…”

“…The accuracy of the voltage mapping during SR was limited after multiple DC shocks in the non‐PAF patients. Caixal et al 19 demonstrated that LGE intensity was associated with log‐transformed bipolar voltage and conduction velocity in SR. The authors speculated that far‐field potentials might conceal small local electrograms.…”

Non-Invasive and Quantitative Estimation of Left Atrial Fibrosis Based on P Waves of the 12-Lead ECG—A Large-Scale Computational Study Covering Anatomical Variability

“…High intensity areas on late Gadolinium enhancement magnetic resonance images (LGE-MRI) as well as low bi- and unipolar electrogram voltages [ 7 , 8 , 9 ] during electrophysiological studies are currently drawn on to identify the amount and spatial location of scars and fibrosis on the atrial wall. However, LGE-MRI is a cost-intensive imaging technique for which technical parameters have to be carefully selected and the segmentation of MR images is cumbersome and challenging [ 10 ].…”

Using Machine Learning to Characterize Atrial Fibrotic Substrate from Intracardiac Signals using a Hybrid in silico and in vivo Dataset

“…Substrate ablation strategies guided by a voltage map derived from the amplitude of intracardiac electrograms define areas based on a cut-off value (frequently < 0.5 mV during sinus rhythm) as pathological tissue and target them for ablation [4][5][6] . Several clinical studies have shown a correlation of fibrosis identified through late gadolinium enhancement magnetic resonance imaging (LGE-MRI) with reduced local signal amplitude ("voltage") in atrial electrograms 7,8 . Using low voltage areas as targets for ablation has not yet shown an optimal and consistent reduction in the rate of recurrent atrial fibrillation [9][10][11] .…”