Detection and Quantification of Left Atrial Structural Remodeling With Delayed-Enhancement Magnetic Resonance Imaging in Patients With Atrial Fibrillation

Abstract

Background Atrial fibrillation (AF) is associated with diffuse left atrial (LA) fibrosis and a reduction in endocardial voltage. These changes are indicators of AF severity and appear to be predictors of treatment outcome. In this study we report the utility of delayed enhancement MRI (DE-MRI) in detecting abnormal atrial tissue prior to radiofrequency ablation and in predicting procedural outcome. Methods and Results Eighty-one patients presenting for pulmonary vein antrum isolation (PVAI) for treatment of AF underwent 3D DE-MRI of the LA prior to the ablation. Six healthy volunteers were also scanned. DE-MRI images were manually segmented to isolate the LA and custom software was implemented to quantify the spatial extent of delayed enhancement, which was then compared to the regions of low voltage from electroanatomical maps from the PVAI procedure. Patients were assessed for AF recurrence at least six months following PVAI with average follow-up of 9.6 ± 3.7 months (range = 6 to 19 months). Based on the extent of pre-ablation enhancement, 43 patients were classified as having minimal enhancement (average enhancement = 8.0% ± 4.2%), 30 as moderate (enhancement = 21.3% ± 5.8%), and 8 as extensive (enhancement = 50.1% ± 15.4%). The rate of AF recurrence was 6 patients (14.0%) with minimal enhancement, 13 (43.3%) with moderate and 6 (75%) patients with extensive enhancement (p <0.001). Conclusion DE-MRI provides a non-invasive means of assessing LA myocardial tissue in patients suffering from AF and might provide insight into the progress of the disease. Pre-ablation DE-MRI holds promise to predict responders to AF ablation and may provide a metric of overall disease progression.

Atrial remodelling in heart failure: recent developments and relevance for heart failure with preserved ejection fraction

“…Cardiac magnetic resonance late gadolinium enhancement regions are used to characterize atrial fibrous remodelling 11. Magnetic resonance imaging (MRI) T1 mapping allows to assess the degree of fibrosis in ventricular remodelling; however, it has failed to convincingly do so in the LA 12.…”

Automatic Segmentation of Left Atrial Geometry from Contrast-Enhanced Magnetic Resonance Images Using a Probabilistic Atlas

“…7). Studying the temporal process of scar formation is pro-viding new insights into the progression and recovery of the disease process [11]. With a better atlas, the method is promising and has the potential of being applied to other imaging modalities such as free-breathing non-contrast MRA, a new recent technique in imaging.…”

“…AF recurrence is not uncommon in patients who underwent ablation treatment and is generally caused by the rejuvenation of scarred tissues. Understanding the temporal process of scar formation and whether scar reduces or expands over time has become important in determining whether some patients are more susceptible to AF recurrence than others [11].…”

Economic Incentives and Use of the Intensive Care Unit

“…Increased ICU bed availability could only cause increased harm in the presence of supplier-induced demand; eg, when a clinician or hospital system profits by advising a less-informed patient to consume services the patient would not want if he or she knew all the facts. 2 Demonstrating the existence of induced demand is controversial and requires cautious investigation of a change in profitability, causing a change in the volume of care consumed. 3 In addition, for demand to be induced, the evaluating physician must be concerned with the hospital's profit from maintaining full ICU capacity.…”

“…Evidence validating left atrial fibrosis quantification on MRI is mounting with compelling histological, electrical, and clinical data. [1][2][3] Detection of myocardial injury and remodeling using delayed enhancement MRI sequences is a well-validated technique dating back to the landmark histological study by Kim et al, 4 which helped launch delayed enhancement MRI as the criterion standard for tissue viability testing.…”