A comparison of late gadolinium enhancement magnetic resonance imaging and left atrial endocardial voltage

Abstract

Background Following catheter ablation for atrial fibrillation (AF), late gadolinium enhancement magnetic resonance imaging (LGE MRI) may be able to visualise areas of fibrosis and therefore reduced endocardial voltage. Unlike previous studies describing qualitative visual comparisons, we have developed a new quantitative technique for comparison of left atrial (LA) endocardial voltage with 3D LGE MRI signal intensity and have applied it in patients undergoing repeat left atrial ablation. Methods Ten patients who had undergone previous catheter ablation for AF, and who represented with either paroxysmal AF (n=4) or atrial tachycardia (AT) (n=6) underwent pre-ablation LGE MRI. A 3D LA reconstruction was created by projecting the LGE data on to a segmented LA shell (signal intensities were displayed as the number of standard deviations (SD) from the mean signal intensity of the atrial blood pool). During the ablation procedure, high density (mean number of points: 368 ± 127) LA endocardial voltage maps were acquired in either sinus rhythm or AT using CARTO 3 (Biosense Webster). The 3D LGE MRI reconstructions and endocardial voltage maps were manually segmented into LA regions (left and right WACA, roof, mitral line, anterior, posterior, inferior, septum and lateral) using custom-written software to derive the mean signal intensity and endocardial voltage for each segment. Results