Left Atrial Late Gadolinium Enhancement Research Articles

The association of baseline left atrial structure and function measured with cardiac magnetic resonance and pulmonary vein isolation outcome in patients with drug-refractory atrial fibrillation

Prognostic significance of left atrial (LA) function in patients with atrial fibrillation (AF) is poorly defined. To examine the association of LA function measured with cardiac magnetic resonance (CMR) feature-tracking and AF recurrence following catheter ablation. One hundred and twenty-one AF patients (72% paroxysmal, mean age 59 ± 10 years) were enrolled. Baseline LA function was measured by calculating passive, active, and total emptying fractions (LAEF) and analysis of global longitudinal strain and strain rates. Patients were followed up for recurrence of AF or atrial tachycardia (AT). Hazard ratios for recurrence were calculated using Cox proportional models adjusted for potential clinical confounders, type of AF, left ventricular ejection fraction, AF duration, LA volume, and late gadolinium enhancement (LGE). During a mean follow-up of 18 ± 9 months, 52 patients (43%) experienced recurrent AF/AT. Patients with recurrent AF/AT had higher baseline LA volume index and lower LA passive, and total LAEF (P < .05 for all). The baseline peak LA strain and strain rates in all phases of LA function were lower in the AF/AT recurrence group (P < .01 for all). In multivariable analysis total LAEF, peak LA strain, and systolic and late diastolic strain rates were associated with recurrence. Both peak LA strain and total LAEF improved prediction of recurrent AT/AF compared to the baseline clinical model, including LA LGE (C statistic 0.82 vs 0.77, P < .05 for both total LAEF and peak LA strain). LA reservoir function was independently associated with recurrent AF/AT after PVI and can additionally improve risk stratification in patients undergoing PVI.

Left Atrial LGE and Arrhythmia Recurrence Following Pulmonary Vein Isolation for Paroxysmal and Persistent AF

ObjectivesThe aims of this study were to: 1) use a novel method of late gadolinium enhancement (LGE) quantification that uses normalized intensity measures to confirm the association between LGE extent and atrial fibrillation (AF) recurrence following ablation; and 2) examine the presence of interaction and effect modification between LGE and AF persistence. BackgroundRecurrent AF after catheter ablation has been reported to associate with the baseline extent of left atrial LGE on cardiac magnetic resonance. Traditional methods for measurement of intensity lack an objective threshold for quantification and interpatient comparisons of LGE. MethodsThe cohort included 165 participants (mean age 60.0 ± 10.2 years, 77% men, 57% with persistent AF) who underwent initial AF ablation. The association of baseline LGE extent with AF recurrence was examined using multivariable Cox proportional hazards models. Multiplicative and additive interactions between AF type and LGE extent were examined. ResultsDuring 10.2 ± 5.7 months of follow-up, 63 patients (38.2%) experienced AF recurrence. Baseline LGE extent was independently associated with AF recurrence after adjusting for confounders (hazard ratio: 1.5 per 10% increased LGE; p < 0.001). The hazard ratio for AF recurrence progressively increased as a function of LGE. The magnitude of association between LGE >35% and AF recurrence was greater among patients with persistent AF (hazard ratio: 6.5 [p = 0.001] vs. 3.6 [p = 0.001]); however, there was no evidence for statistical interaction. ConclusionsRegardless of AF persistence at baseline, participants with LGE ≤35% have favorable outcomes, whereas those with LGE >35% have a higher rate of AF recurrence in the first year after ablation. These findings suggest a role for: 1) patient selection for AF ablation using LGE extent; and 2) substrate modification in addition to pulmonary vein isolation in patients with LGE extent exceeding 35% of left atrial myocardium.

Lack of regional association between atrial late gadolinium enhancement on cardiac magnetic resonance and atrial fibrillation rotors

The extent of left atrial (LA) late gadolinium enhancement (LGE), as a surrogate for fibrosis, has been associated with atrial fibrillation (AF) recurrence after catheter ablation. Furthermore, there is ex vivo evidence that islands of fibrosis may anchor fibrillatory rotors. The purpose of this study was to examine the anatomical association of AF rotors with LA and right atrial (RA) LGE on cardiac magnetic resonance. The cohort included 9 patients with persistent AF (mean age 61.1 ± 9.7 years) who underwent LGE cardiac magnetic resonance before AF ablation using the focal impulse and rotor modulation system. The extent of LA and RA LGE was quantified globally and in each of the 7 sectors: LA posterior/inferior wall, anterior wall, roof, left and right pulmonary vein antra, and RA lateral and septal regions. The multivariable association of rotor incidence with global and per sector LGE extent was examined using multivariable Bernoulli logistic regression estimated by generalized estimating equations. The mean RA and LA volumes were 113.2 ± 37.31 and 143.03 ± 58.25 mL, respectively. The mean RA and LA LGE burden was 17.2% ± 11.0% and 17.4% ± 14.4%, respectively. A total of 18 LA rotors and 9 RA rotors were identified in all patients. No univariable or multivariable association was observed between global or per sector LGE extent and focal impulse and rotor modulation rotor incidence. In this cohort of patients, there was no association between AF rotor incidence and the global or regional extent of RA and LA LGE.

Characterization of Cardiac Amyloidosis by Atrial Late Gadolinium Enhancement Using Contrast-Enhanced Cardiac Magnetic Resonance Imaging and Correlation With Left Atrial Conduit and Contractile Function

The diagnosis of cardiac amyloidosis (CA) often necessitates invasive myocardial biopsy. We sought to evaluate whether late gadolinium enhancement (LGE) of the atrial myocardium by cardiac magnetic resonance imaging was associated with impaired left atrial (LA) function and whether the extent of LA LGE may enhance diagnostic differentiation of CA from other cardiomyopathies. Twenty-two patients with biopsy-proven CA, 37 with systemic hypertension (SH), and 22 with nonischemic dilated cardiomyopathy (NIDC) underwent cardiac magnetic resonance imaging and echocardiographic evaluation. Patients with CA had greater minimal LA volume (57 ± 53 vs 24 ± 18 in SH and 19 ± 25% in NIDC, p= 0.003), and significantly lower total LA emptying function (19 ± 14 vs 40 ± 14 in SH and 33 ± 20% in NIDC, p= 0.0006). The mean proportion of atrial enhancement (LGELA%) was significantly greater in patients with CA than with SH and NIDC (59 ± 36% vs 7.4 ± 2.1 and 2.9 ± 9.0%, p <0.0001, respectively). There was also a strong inverse correlation between both active and total atrial emptying (r=-0.69, p= 0.001; r=-0.67, p= 0.01, respectively) with LGELA% for patients with CA. In multivariate regression analysis, LGELA% was the strongest adjusted predictor for CA diagnosis. Using receiver operating characteristic analysis, LGELA% ≥33% produced the greatest diagnostic utility for CA (sensitivity 76%, specificity 94%). Patients with CA may have extensive LGE of the LA myocardium, which is associated with marked reduction in LA emptying function. The extent of LA LGE was highly predictive for the diagnosis of CA.

Left atrial late gadolinium enhancement and mitral regurgitation in subjects with atrial fibrillation

Background Late gadolinium enhancement (LGE) is used to evaluate fibrosis of the left atrium (LA) in subjects with atrial fibrillation (AF). LA fibrosis by LGE has been shown to correlate with LA volumes. However, within AF subjects, the association of mitral regurgitation (MR) with LA LGE is not well described. Pathological studies have demonstrated atrial fibrosis and tissue disorganization in cardiac diseases, including valvular disease. The current study evaluates the relationship between LA LGE, LA volumes, and MR in subjects with AF.

Comparison of preexisting and ablation-induced late gadolinium enhancement on left atrial magnetic resonance imaging.

Postablation atrial fibrillation recurrence is positively associated with the extent of preexisting left atrial (LA) late gadolinium enhancement (LGE) on magnetic resonance imaging (MRI), but negatively associated with the extent of postablation LGE regardless of proximity to the pulmonary vein antra. The characteristics of pre- vs postablation LA LGE may provide insight into this seeming paradox and inform future strategies for ablation. The purpose of this study was to define the characteristics of preexisting vs ablation-induced LA LGE. LGE-MRI was prospectively performed before and ≥3 months after initial ablation in 20 patients. The intracardiac locations of ablation points were coregistered with the corresponding sites on axial planes of postablation LGE-MRI. The image intensity ratio (IIR), defined as the LA myocardial MRI signal intensity divided by the mean LA blood pool intensity, and LA myocardial wall thickness were calculated on pre- and postablation images. Imaging data from 409 pairs of pre- and postablation axial LGE-MRI planes and 6961 pairs of pre- and postablation image sectors were analyzed. Ablation-induced LGE revealed a higher IIR, suggesting greater contrast uptake and denser fibrosis, than did preexisting LGE (1.25 ± 0.25 vs 1.14 ± 0.15; P < .001). In addition, ablation-induced LGE regions had thinner LA myocardium (2.10 ± 0.67 mm vs 2.37 ± 0.74 mm; P < .001). Regions with ablation-induced LGE exhibit increased contrast uptake, likely signifying higher scar density, and thinner myocardium as compared with regions with preexisting LGE. Future studies examining the association of postablation LGE intensity and nonuniformity with ablation success are warranted and may inform strategies to optimize ablation outcome.

Clinical value of assessment of left atrial late gadolinium enhancement in patients undergoing ablation of atrial fibrillation

BackgroundLeft atrial (LA) fibrosis begets atrial fibrillation (AF). Cardiovascular magnetic resonance (CMR) using the late gadolinium enhancement (LGE) technique might visualize the LA fibrosis and thus help to choose an appropriate strategy for treatment of AF. In this regard, we investigated whether the extent of preablation LA LGE would predict AF recurrence after ablation in a non-selected patient population. MethodsCMR was performed in 95 patients before radiofrequency ablation of AF. An interpretable scan was available in 73 patients (age, 59±8years; men, 71%; persistent/paroxysmal AF, 55/45%). The extent of LA LGE was quantified by three established thresholding techniques. In addition, CMR was used to quantify LA volume and reservoir function. The patients were followed for AF recurrence for 1.3±0.8years. ResultsThe arrhythmia recurred in 29 (40%) of the patients. The extent of LA LGE did not differ between paroxysmal and persistent AF and it did not predict the AF recurrence. Moreover, the extent of LA LGE did not correlate with LA volume, reservoir function and bipolar voltage. ConclusionsOur data indicate a limited value of a routine assessment of LA LGE before ablation of AF. Further experimental and clinical researches should be done before applying the method to a wide clinical practice.

Left atrial remodeling by MRI: comparison in patients with and without cardiovascular disease

Background Pre-existent scar in the left atrium (LA) is hypothesized to be the arrhythmic substrate of atrial fibrillation (AF) [1,2], and has been characterized in cardiac MR studies [3] using high resolution late gadolinium enhancement (LGE) [4]. Recent pathology studies show that LA fibrosis extent is similar in patients with AF vs. other cardiovascular disease (CVD) [5], e.g. valvular disease, ischemic and non-ischemic cardiomyopathies. Our aim was replicate these pathology findings by comparing patterns of enhancement on LGE in patients with and without CVD. Methods Forty-eight patients were imaged at our center on a 1.5T scanner (MAGNETOM Espree, Siemens Healthcare, Erlangen), having good-quality LGE studies with visibly enhanced mitral valves, and no prior pulmonary vein isolation. Left atrial LGE was obtained using an ECG-triggered, navigator-gated 3D GRE inversion recovery (IR) sequence obtained 10-20 minutes after the administration of 0.2 mmol/kg of Gadobutrol, with spatial resolution of 1.5 × 1.4 × 3 mm3. A blinded assessment of enhancement/scar (0 = absent, 1 = present) was performed in an 18 segment

Optimal Techniques for Late Gadolinium-Enhanced MRI: Comparison of Delay Time, Slice Thickness, and Multiplanar Reconstruction vs Maximum Intensity Projection for Assessment of Fibrosis in Atrial Fibrillation

Background Left atrial (LA) late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) has varying protocols, which may limit interstudy comparisons. This study evaluates whether changes in image acquisition and reconstruction parameters affect quantification of LA LGE MRI. Methods A total of 200 LGE MRI scans were prepared using various techniques from 5 subjects. 3D respiratory and ECG-gated LGE images were acquired at 15, 20, 25, and 30 minutes after contrast. Multiplanar reconstructions (MPR) and maximum intensity projections (MIP) were created from 3D data at various slice thicknesses. LA LGE was quantified with image intensity ratio (IIR, atrial wall signal intensity divided by blood pool). Mean IIR was calculated for the entire LA as a metric of LGE burden. Additionally, in 42 consecutive preablation patients, local IIR values from 3.5-mm MPR and MIP reconstructions were separately registered to LA electroanatomic voltage maps (EAM) obtained prior to ablation procedure. Results Multitime point LGE-MRI showed a rise in baseline mean IIR of 0.5% ± 0.1% per minute ( P P P P Conclusions Variations in timing of acquisition, image reconstruction methods, and slice thickness result in changes in LA LGE quantity.

Left atrial late gadolinium enhancement with water–fat separation: The importance of phase‐encoding order

To compare two late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) methods: a Dixon LGE sequence with sequential phase-encoding order, reconstructed using water-fat separation, and standard fat-saturated LGE. We implemented a dual-echo Dixon LGE method for reconstructing water-only images and compared it to fat-saturated LGE in 12 patients prior to their first pulmonary vein isolation (PVI) procedure. Images were analyzed for quality and fat-suppression. Regions of the left atrium were evaluated by a blinded observer (1 = prominent enhancement, 0 = mild or absent enhancement) on two sets of images (fat-saturated and water-only LGE) and agreement was assessed. Water-only LGE showed a trend toward better fat-suppression (P = 0.06), with a significantly more homogeneous blood pool signal and reduced inflow artifacts (both P < 0.01). Agreement between fat-saturated LGE and water-only methods was found in 84% of regions, significantly correlated by chi-squared test (P < 0.001). The kappa value was 0.52 (moderate). The average number of enhancing segments was higher for fat-saturated LGE than water-only LGE (4.2 ± 2.7 vs. 3.2 ± 2.9, P = 0.03). The two-point Dixon LGE technique reduces artifacts due to a centric k-space order. A similar enhancement pattern was observed irrespective of the LGE technique, with more enhancement detected by fat-saturated LGE.

Accelerated Late Gadolinium Enhancement Cardiac MR Imaging with Isotropic Spatial Resolution Using Compressed Sensing: Initial Experience

To evaluate the use of low-dimensional-structure self-learning and thresholding (LOST) compressed sensing acquisition and reconstruction in the assessment of left atrial (LA) and left ventricular (LV) scar by using late gadolinium enhancement (LGE) magnetic resonance (MR) imaging with isotropic spatial resolution. The study was approved by the local institutional review board and was compliant with HIPAA. All subjects provided written informed consent. Twenty-eight patients (eight women; mean age, 58.0 years ± 10.1) with a history of atrial fibrillation were recruited for the LA LGE study, and 14 patients (five women; mean age, 54.2 years ± 18.6) were recruited for assessment of LV myocardial infarction. With use of a pseudorandom k-space undersampling pattern, threefold accelerated three-dimensional (3D) LGE data were acquired with isotropic spatial resolution and reconstructed off-line by using LOST. For comparison, subjects were also imaged by using standard 3D LGE protocols with nonisotropic spatial resolution. Images were compared qualitatively by three cardiologists with regard to diagnostic value, presence of enhancement, and image quality. The signed rank test and Wilcoxon unpaired two-sample test were used to test the hypothesis that there would be no significant difference in image quality ratings with different resolutions. Interpretable images were obtained in 26 of the 28 patients (93%) in the LA LGE study. LGE was seen in 17 of 30 cases (57%) with nonisotropic resolution and in 18 cases (60%) with isotropic resolution. Diagnostic quality scores of isotropic images were significantly higher than those of nonisotropic images with coronal views (median, 3 vs 2, respectively [25th and 75th percentiles: 3, 3 vs 2, 3]; P < .001) and sagittal views (median, 3 vs 2 [25th and 75th percentiles: 3, 4 vs 2, 3]; P < .001) but lower with axial views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 3, 3]; P < .001). For the LV LGE study, all patients had interpretable images. LGE was seen in six of 14 patients (43%), with 100% agreement between both data sets. Diagnostic quality scores of high-isotropic-resolution LV images were higher than those of nonisotropic images with short-axis views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 2, 3]; P = .014) and two-chamber views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 2, 3]; P = .001). An accelerated LGE acquisition with LOST enables imaging with high isotropic spatial resolution for improved assessment of LV, LA, and pulmonary vein scar.

Left atrial late gadolinium enhancement following external beam radiation for lymphoma: a potential model for exploring radiation-related heart disease

We are able to detect subclinical post-irradiation changes to the heart with left atrial late gadolinium enhanced magnetic resonance imaging (LGE-MRI).

Abstract 16972: Abnormalities of the Aorta Are Common Following Pulmonary Vein Isolation: A Cardiac Magnetic Resonance Imaging Study

BACKGROUND: Esophageal injury has been reported following pulmonary vein isolation (PVI), but few data are known regarding involvement of other mediastinal structures such as the aorta. Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMR) has been used to identify myocardial fibrosis and inflammation, and may provide a way of identifying extramyocardial involvement. We sought to determine the frequency of aortic wall LGE post-PVI to examine potential aortic involvement. METHODS: Consecutive patients who underwent their first PVI with pre and post-LGE CMR at our institution between 2009-2011 were retrospectively identified. Left atrial (LA) and aortic wall hyperenhancement were analyzed using a commercial workstation (QMass MR). LA and aortic hyperenhancement were defined as any evidence of LGE at 10 standard deviations (SD) greater than the mean signal intensity of the aortic blood pool. Studies were visually assessed for geometric contact between the LA and aorta. RESULTS: Of 46 patient datasets meeting entry criteria, 9 were excluded due to poor quality CMR, leaving 37 patients (age 60.5 + 8.6 years, 68% male) and 74 studies for analysis. No patient had evidence of a clinical aortic complication. Aortic wall LGE was seen in 35% (13/37) pre-PVI and in 57% (21/37) post-PVI (p= 0.068). All (100%) patients with post-PVI aortic wall enhancement also had post-PVI LA hyperenhancement (Figure 1). The vast majority (85%) of patients with aortic wall LGE post-PVI had direct contact of the LA and aortic wall on the pre-PVI CMR study. CONCLUSION: Aortic wall LGE is common post-PVI, with a universal finding of concomitant LA LGE in all patients with aortic enhancement. The vast majority of those with aortic LGE had direct contact of the left atrium and aorta. These data suggest that LGE CMR evidence of aortic involvement post-PVI is common. The clinical implications of this imaging abnormality remain to be defined.

CMR findings in patients with hypertrophic cardiomyopathy and atrial fibrillation.

ObjectivesWe sought to evaluate the relation between atrial fibrillation (AF) and the extent of myocardial scarring together with left ventricular (LV) and atrial parameters assessed by late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM).BackgroundAF is the most common arrhythmia in HCM. Myocardial scarring is also identified frequently in HCM. However, the impact of myocardial scarring assessed by LGE CMR on the presence of AF has not been evaluated yet.Methods87 HCM patients underwent LGE CMR, echocardiography and regular ECG recordings. LV function, volumes, myocardial thickness, left atrial (LA) volume and the extent of LGE, were assessed using CMR and correlated to AF. Additionally, the presence of diastolic dysfunction and mitral regurgitation were obtained by echocardiography and also correlated to AF.ResultsEpisodes of AF were documented in 37 patients (42%). Indexed LV volumes and mass were comparable between HCM patients with and without AF. However, indexed LA volume was significantly higher in HCM patients with AF than in HCM patients without AF (68 ± 24 ml·m-2 versus 46 ± 18 ml·m-2, p = 0.0002, respectively). The mean extent of LGE was higher in HCM patients with AF than those without AF (12.4 ± 14.5% versus 6.0 ± 8.6%, p = 0.02). When adjusting for age, gender and LV mass, LGE and indexed LA volume significantly correlated to AF (r = 0.34, p = 0.02 and r = 0.42, p < 0.001 respectively). By echocardiographic examination, LV diastolic dysfunction was evident in 35 (40%) patients. Mitral regurgitation greater than II was observed in 12 patients (14%). Multivariate analysis demonstrated that LA volume and presence of diastolic dysfunction were the only independent determinant of AF in HCM patients (p = 0.006, p = 0.01 respectively). Receiver operating characteristic curve analysis indicated good predictive performance of LA volume and LGE (AUC = 0.74 and 0.64 respectively) with respect to AF.ConclusionHCM patients with AF display significantly more LGE than HCM patients without AF. However, the extent of LGE is inferior to the LA size for predicting AF prevalence. LA dilation is the strongest determinant of AF in HCM patients, and is related to the extent of LGE in the LV, irrespective of LV mass.

Baby boom, population aging, and capital markets : Gudrip S. Bakshi (University of New Orleans) and Zhiwu Chen (University of Winconsin-Madison)

&#x0D; &#x0D; &#x0D; This article tests how demographic changes affect capital markets. The life-cycle investment hypothesis states that at an early stage an investor allocates more wealth in housing and then switches to financial assets at a later stage. Consequently, the stock market should rise but the housing market should decline with the average age, a prediction supported in the post-1945 period. The second hypothesis that an investor’s risk aversion increases with age is tested by estimating the resulting Euler equation and supported in the post 1945 period. A rise in average age is found to predict a rise in risk premiums. Journal ofBusiness, 1994,67(2): 165-202. (Reprinted with permission of the Journaf of Business.)&#x0D; &#x0D; &#x0D;