CMR Prediction of Voltage and Gaps Before Repeat Ablation | Journal Scan
Can cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) predict atrial voltage recordings and electrical reconnection in patients undergoing repeat ablation procedures for atrial fibrillation and atrial tachycardia?
This study evaluated 20 patients with prior left atrial (LA) catheter ablation for atrial fibrillation or atrial tachycardia planned for a clinically indicated repeat procedure. CMR with LGE was performed to characterize LA tissue. CMR LGE patterns were compared to atrial voltage recordings to assess their relationship and to determine whether CMR can predict electrical reconnection in patients undergoing repeat ablation procedures.
A total of 6,767 data points from 20 patients were compared, and only 119 points (1.8%) had a low voltage of ≤0.05 mV. There was a weak correlation between voltage (r = -0.18 to -0.17) and LGE CMR signal. When signal intensities within a 5 mm radius of each voltage point were considered, the correlations remained weak (r = -0.21 to -0.19). There was no significant difference in mean or minimum LGE CMR signal intensity between electrically isolated and reconnected sites (p = 0.13-0.73).
LGE by CMR is an unreliable method to predict endocardial voltage and identify electrically reconnected sites in patients undergoing repeat LA ablation procedures for atrial fibrillation and atrial tachycardia.
In contrast to some (but not all) earlier studies, this paper finds that LGE by CMR is not able to reliably distinguish electrically isolated versus reconnected sites in patients undergoing repeat ablation procedures for atrial fibrillation or atrial tachycardia. Significant challenges remain for LGE CMR of the atria: significant and variable artifacts can be present, there is no consensus for imaging timing after contrast and specific contrast agent and dose, image signal varies significantly between patients and prevents reliable quantification, CMR has limited spatial resolution for imaging the thin-walled atria, and co-registration of CMR and endocardial voltage maps remain challenging. Despite initial studies that were promising, this manuscript suggests that we need to go back to the drawing board and address these limitations, or try an alternative approach.
Keywords: Artifacts, Arrhythmias, Cardiac, Atrial Appendage, Atrial Fibrillation, Catheter Ablation, Contrast Media, Endocardium, Gadolinium, Heart Atria, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Tachycardia, Supraventricular
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