Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging Research Articles

Novel systematic processing of cardiac magnetic resonance imaging identifies target regions associated with infarct-related ventricular tachycardia

Abstract Introduction In the clinic, complete characterization of reentrant ventricular tachycardia (VT) circuits using classical electrophysiological criteria and state-of-the-art high density mapping during VT is complex, and often cannot be completed because of hemodynamic instability. This common limitation has motivated the implementation of mapping strategies during sinus rhythm or ventricular pacing aiming to identify scar regions associated with VT isthmuses or potential arrhythmogenicity. Complementary imaging-based strategies including advanced analyses of scar tissue characteristics have been also proposed for procedure planning and identification of potential arrhythmogenic regions. However, the most recent expert consensus report on catheter ablation of ventricular arrhythmia highlights the lack of agreement on the preferable signal intensity (SI) cut-off values for assessment of tissue heterogeneity and scar areas on late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) images. The latter makes LGE-CMR imaging processing highly operator-dependent and potentially sensitive to selection bias. Purpose We aimed at developing and validating a systematic processing approach on LGE-CMR images to identify potential VT corridors that may include protected isthmuses associated with VT maintenance. Methods Translational study including 18 pigs with established myocardial infarction and inducible VT undergoing in vivo characterization of the anatomical and functional myocardial substrate associated with VT maintenance. Clinical validation was conducted in a multicenter series of 33 patients with ischemic cardiomyopathy undergoing VT ablation. Three-dimensional CMR-LGE images were processed using systematic scanning of 15 signal intensity cut-off ranges to obtain surface visualization of all potential VT corridors. Analysis and comparisons of imaging and electrophysiological data were performed in individuals with full electrophysiological characterization of the isthmus sites of at least one VT morphology. Results In both the experimental pig model and patients undergoing VT ablation, all the electrophysiologically-defined isthmus sites (n=11 and n=19, respectively) showed overlapping regions with CMR-based potential VT corridors. Such imaging-based VT corridors were less specific than electrophysiologically-guided ablation lesions at functionally relevant isthmus sites (Figure). However, in patients, decreasing from 15 to 7 the number of signal intensity cut-off ranges for systematic imaging processing significantly reduced the area of imaging-based potential VT corridors, without diminishing the capability to detect functionally relevant VT isthmus sites. Conclusions Systematic processing of 3D LGE-CMR images provides unbiased identification of imaging based potential VT corridors that contain functionally relevant protected isthmus sites.

An optimized multisource acquisition and registration workflow for imaging guided ventricular tachycardia ablation

Abstract Background Catheter ablation is a cornerstone treatment for scar-related ventricular arrhythmias arising in patients affected by structural heart disease. Imaging integration with electroanatomical mapping (EAM) suites for ventricular tachycardia (VT) ablation procedural guidance is an established step for advanced substrate characterization and treatment. Purpose To compare and validate different approaches for intraprocedural multisource imaging registration and integration with EAM suites for VT ablation guidance. Methods Thirty consecutive patients prospectively enrolled in the ongoing VOYAGE clinical trial for imaging guided/aided VT ablation at our center were retrospectively analyzed. Multidetector computed tomography (MDCT) and late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging was performed before procedure. MDCT and LGE-CMR images were both acquired during end-expiratory breath hold. Same cardiac cycle phase images were used. Wide band LGE-CMR was acquired in case of a cardiac implantable electronic device was present to reduce artifacts. Images were imported in ADAS3D software. MDCT and CMR images were manually registered using established anatomical landmarks (left ventricle outflow tract, left ventricle apex, papillary muscles, left and right ventricle junction), were then respectively processed for aortic/ventricular anatomical reconstruction and myocardial characterization and then imported in CARTO3 electroanatomical mapping suite for procedural guidance. Registration between EAM and imaging was either performed with ascending aorta fast anatomical mapping (FAM) and 3D landmark alignment with aortic MDCT or via intracardiac echocardiography (ICE) left ventricle (LV) chamber segmentation and 3D landmark alignment with ventricular MDCT. ICE segmentation was also obtained for every case regardless of aortic FAM. Surface match between ICE and MDCT LV chamber reconstructions was calculated for method comparison. Results All 30 patients had an ICE segmentation of the LV, with a mean of 15,66±4,89 contours. Aortic FAM was obtained and used for aortic MDCT registration in 10 subjects. LV ICE was instead used for imaging alignment in 20 subjects. When compared to aortic FAM, LV ICE to LV MDCT alignment achieved lower average surface distance (3,86±1,41 mm vs 8,884±6,77 mm; p<0,001), lower minimum surface distance (0,002±0,03 vs 0,07±0,06; p= 0,001) and lower maximum surface distance (14,16±4,37 vs 22,93±11,10; p<0,001). Conclusion An optimized workflow consisting of ICE LV chamber segmentation was superior in terms of 3D surface distance to aortic FAM reconstruction to obtain reliable multisource imaging registration for MDCT/CMR guided/aided VT ablation.

Cardiac magnetic resonance - aided ventricular tachycardia substrate ablation

Abstract Objectives To assess feasibility and reliability of Cardiac magnetic resonance (CMR)-derived pixel signal intensity (PSI) maps obtained by Three Dimensional (3D)- Late Gadolinium Enhancement (LGE) images for detecting potential targets for VT substrate ablation procedures. Background Parametric imaging with color-coded PSI maps obtained from pre-ablation 3D LGE -CMR imaging can be used for identification and characterization of arrhythmic abnormal substrate. Recent publications have shown that PSI maps permit visualization of border zone areas inside the scar. Specifically, corridors of viable tissue within the scar connecting healthy myocardium define VT corridors that may be the electrical equivalent of the abnormal conducting channels on the electroanatomical mapping (EAM). Methods 8 patients with scar-dependent monomorphic VTs who underwent 3D-LGE CMR imaging prior to substrate ablation were included in the study. The studies were performed at 1.5T scanner. We obtained two data sets of 3D whole heart LGE imaging with high resolution. Patients underwent two acquisitions: the conventional respiratory navigated, electrocardiographically-gated 3D fast gradient echo (1.3slice thickness, 256x256 matrix acquisition) and the image-navigated isotropic high resolution 3D GE with Dixon water-fat separation. 3D LGE-CMR images were processed with ADAS-VT software to produce a 3-dimensional model of the heart with 10 layers from the endocardium to epicardium and PSI maps color-coded from the LGE data projected to each of the shells (Figure 1). In the LGE-CMR PSI maps, VT corridors were obtained automatically by the ADAS VT software. Subsequently, data were given to the electrophysiologists and merged with the CARTO3 system EAM data obtained for the ablation (Figure2). CMR information was used to facilitate the identification of target ablation sites in the areas identified by CMR as abnormal substrate and radiofrequency was applied in the presence of both a pathological electrogram (EGM) and a VT corridor as identified by CMR. Results There was a 95% agreement between the abnormal conducting channels as detected by abnormal electrograms in the EAM and the VT corridors identified by 3D LGE CMR imaging. In two occasions, there was one VT corridor that did not correlate with abnormal electrograms and was not ablated. The two 3D LGE sequences used for ADAS-VT corridors analysis showed complete agreement in the number and location of VT corridors. Mean acquisition time for 3D LGE imaging was 11±4minutes for the conventional fast gradient echo sequence, and 5±2minutes for the novel 3D self-image navigated LGE sequence. The image quality of 3D LGE was superior with the Dixon fat-water separation. Overall CMR-aided VT ablation reduced the procedural and fluoroscopy time by 40%. Conclusions CMR-aided VT ablation is feasible, reliable and significantly reduces the procedural time.

Correlation Between Corrected TIMI Frame Count with the Extent of Myocardial Fibrosis on ST-Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention

Background: Microvascular injury after primary percutaneous coronary intervention (PPCI) reperfusion contributes to necrosis propagation. Corrected TIMI Frame Count (CTFC) is a surrogate marker of microvascular dysfunction and can stratify in-hospital mortality risk in patients with final TIMI flow 3. The extent of myocardial fibrosis after STEMI is associated with a higher incidence of major cardiovascular events. This study aimed to determine the relationship between CTFC in the infarct-related artery and myocardial fibrosis area based on cardiac magnetic resonance (CMR) in STEMI patients undergoing PPCI.Methods: This retrospective cohort study included 31 STEMI patients who had undergone PPCI and CMR examination between days 60 and 75 after STEMI as the sample. CTFC was measured in the infarct-related artery from post-PPCI angiogram recordings. Myocardial fibrosis area was measured from late gadolinium enhancement CMR (LGE-CMR) imaging results.Results: In this study, the mean age was 51.61±10.49 years, 90.3% were male, non-anterior infarction location was 58.1%, mean total ischemic time was 489.48±228.33 minutes, mean CTFC was 27.4±9.3 frames, and mean myocardial fibrosis was 18.33±7.87%. There was no significant correlation found between CTFC and myocardial fibrosis (p=0.530), however total ischemic time had a positive and significant correlation with myocardial fibrosis (p=0.025, r=0.403).Conclusion: CTFC in the infarct-related artery is not correlated with myocardial fibrosis area in STEMI patients undergoing PCI.

Catheter ablation of parahisian premature ventricular complexes in patients with and without cardiac scar

BackgroundAblation of premature ventricular complexes (PVCs) originating from the parahisian area is challenging. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) scar may influence procedural outcomes; the impact of cardiac scar on parahisian PVCs has not been described. ObjectiveThe objective of this study was to examine the incidence and significance of LGE-CMR scarring in patients undergoing ablation for parahisian PVCs. MethodsConsecutive patients who underwent preprocedure LGE-CMR imaging and ablation of parahisian PVCs were included. Acute and long-term outcomes were examined. ResultsForty-eight patients were included (male, n = 37; age, 66 ± 10 years; ejection fraction, 50% ± 12%; preprocedure PVC burden, 21% ± 12%). Intramural LGE-CMR scar was present in 33 of 48 (69%) patients. Cryoablation was used in 9 patients; ablation in multiple chambers was required in 28 (58%) patients. The PVC site of origin (SOO) was intramural (n = 25 patients), left ventricular (n = 5), and right ventricular (n = 18). Patients with LGE-CMR scar were more likely to have intramural PVCs (64% vs 27%; P < .04) and to require ablation in multiple cardiac chambers (58% vs 13%; P < .02). Patients with intramural scar required longer duration of ablation delivery (31 ± 20 minutes vs 17 ± 8 minutes; P < .02). Acute procedural success was 69%; PVC burden on follow-up was 6% ± 9% and similar for those with and without scar. ConclusionAblation of parahisian PVCs often requires mapping and ablation of multiple cardiac chambers, with an intramural SOO identified in most patients. An intramural scar was associated with an intramural SOO of the PVCs requiring more extensive ablation procedures, with similar long-term outcomes compared with those without scar.

Myocardial infarct size for predicting improvements in cardiac function in patients with ischemic cardiomyopathy following coronary artery bypass grafting.

This study used late gadolinium enhancement-cardiac magnetic resonance (LGE-CMR) to assess myocardial infarct size, with the data being employed to predict whether patients with ischemic cardiomyopathy (ICM) would experience improvements in left ventricular function at 6 months following coronary artery bypass grafting (CABG). The data of patients with ICM with left ventricular ejection fraction (LVEF) ≤40% who underwent CABG were retrospectively analyzed. All patients underwent preoperative LGE-CMR imaging. Echocardiography results from 6 months post-CABG were used to assess improvements in LVEF, with improvement being defined as ΔLVEF ≥5%. The value of myocardial infarction segments and infarct size as predictors of improved cardiac function following CABG was analyzed. Of the included patients, 66.7% (52/78) exhibited improved cardiac function at 6 months post-CABG. LGE-CMR imaging data revealed that compared to improved group, the improved group had significantly more myocardial infarct segments [improved group: median 1.0, interquartile range (IQR) 0-3; nonimproved group: median 4.0, IQR 3.0-6.0; P<0.001] and significantly greater myocardial infarct size (improved group: 22.4%±8.2%; nonimproved group: 34.7%±5.9%; P<0.001). The area under the receive operating characteristic curve values for myocardial infarct size in predicting cardiac function improvement were significantly higher than those of myocardial infarct segments (0.88 vs. 0.81; P=0.041). The respective sensitivity and specificity values for using a myocardial infarct size cutoff of 26.4% in differentiating between these 2 patient groups were 92.3% and 71.2%, respectively. According to logistic regression analysis, myocardial infarct size was an independent predictor of nonimprovement in cardiac function [odds ratio (OR) =1.244; 95% confidence interval (CI): 1.114-1.389; P<0.001]. A median 1.6-year follow-up interval (range, 0.5-4.1 years) revealed that the incidences of major adverse cerebrovascular events and cardiovascular events were significantly higher in the nonimproved group (5.8% vs. 26.9%; P<0.001), with these individuals having a higher New York Heart Association grading than patients with improved cardiac function (P=0.019). Myocardial infarct size can be measured to reliably predict improvements in cardiac function in patients with ICM following CABG. These results can guide clinicians in their efforts to identify those patients most likely to achieve positive outcomes following CABG.

Scar conducting channel characterization to predict arrhythmogenicity during ventricular tachycardia ablation.

Heterogeneous tissue channels (HTCs) detected by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) are related to ventricular arrhythmias, but there are few published data about their arrhythmogenic characteristics. We enrolled 34 consecutive patients with ischaemic and non-ischaemic cardiomyopathy who were referred for ventricular tachycardia (VT) ablation. LGE-CMR was performed prior to ablation, and the HTCs were analyzed. Arrhythmogenic HTCs linked to induced VT were identified during the VT ablation procedure. The characteristics of arrhythmogenic HTCs were compared with those of non-arrhythmogenic HTCs. Three patients were excluded due to low-quality LGE-CMR images. A total of 87 HTCs were identified on LGE-CMR in 31 patients (age:63.8 ± 12.3 years; 96.8% male; left ventricular ejection fraction: 36.1 ± 10.7%). Of the 87 HTCs, only 31 were considered arrhythmogenic because of their relation to a VT isthmus. The HTCs related to a VT isthmus were longer [64.6 ± 49.4 vs. 32.9 ± 26.6 mm; OR: 1.02; 95% CI: (1.01-1.04); P < 0.001] and had greater mass [2.5 ± 2.2 vs. 1.2 ± 1.2 grams; OR: 1.62; 95% CI: (1.18-2.21); P < 0.001], a higher degree of protectedness [26.19 ± 19.2 vs. 10.74 ± 8.4; OR 1.09; 95% CI: (1.04-1.14); P < 0.001], higher transmurality [number of wall layers with CCs: 3.8 ± 2.4 vs. 2.4 ± 2.0; OR: 1.31; 95% CI: (1.07-1.60); P = 0.008] and more ramifications [3.8 ± 2.0 vs. 2.7 ± 1.1; OR: 1.59; 95% CI: (1.15-2.19); P = 0.002] than non-arrhythmogenic HTCs. Multivariate logistic regression analysis revealed that protectedness was the strongest predictor of arrhythmogenicity. The protectedness of an HTC identified by LGE-CMR is strongly related to its arrhythmogenicity during VT ablation.

Septal myocardial scar burden predicts the response to cardiac contractility modulation in patients with heart failure

We hypothesized that myocardial septal scarring, assessed by cardiac magnetic resonance (CMR) using late gadolinium enhancement (LGE), at the site of cardiac contractility modulation (CCM) lead placement may predict treatment response. Eligible heart failure (HF) patients underwent LGE CMR imaging before CCM device implantation. The response to CCM therapy at follow-up was determined by a change in NYHA class and echocardiographic left ventricular ejection fraction (LVEF) assessment. Patients were classified as responders, if they showed an improvement in either NYHA class or improvement of LVEF by ≥ 5%. 58 patients were included. 67% of patients were classified as responders according to improved NYHA; 55% according to LVEF improvement. 74% of patients were responders if either NYHA class or LVEF improvement was observed. 90% of responders (according to NYHA class) showed septal LGE < 25% at septal position of the leads, while 44% of non-responders showed septal LGE > 25% (p < 0.01). In patients treated with CCM, an improvement of NYHA class was observed when leads were placed at myocardial segments with a CMR- LGE burden less than 25%.

Abstract 11483: Rationale and Design of Randomized Controlled Trial Evaluating an Atrial Appendage Micrograft Transplantation in Conjunction With Coronary Artery Bypass Surgery

Introduction: In addition to the revascularization therapies for ischemic heart disease (IHD), such as coronary artery bypass grafting (CABG), tissue-engineered cell therapies can help further improve myocardial repair. First clinical results on autologous right atrial appendage-derived micrograft (AAM) transplantation have demonstrated excellent safety and feasibility profiles and suggested a therapeutic effect on myocardial viability. This randomized clinical trial aims to extend the evaluation of efficacy of AAMs transplantation when combined with CABG surgery. Methods and objectives: This double-blinded randomized controlled AAMS2 trial will assess the benefits, safety, and feasibility of the perioperatively assembled and epicardially transplanted AAMs-patch in conjunction with CABG. The trial recruits a total of 50 patients, half of which are randomized to receive the AAMs-patch (CABG+AAMs) and the other half to undergo a standard CABG. Prior to surgery, cardiac structure and function are assessed with late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMRI), electrocardiogram, and transthoracic echocardiography (TTE). LGE-CMRI, electrocardiogram, and TTE are repeated at 6-month follow-up for structural and functional comparisons to baseline. The primary endpoints focus on the efficacy of the AAMs patch as evaluated by LGE-CMRI and TTE as well as changes in health-related quality of life assessments, 6-minute walk test or N-terminal-pro-BNP levels. The secondary endpoints centre on feasibility and safety. For molecular and especially RNA-level analysis of the response to therapy in blood, RNA-stabilized whole blood and plasma samples are collected. Conclusions: The AAMS2 trial is expected to provide further feasibility and safety data as well as insights for efficacy of epicardial AAMs-patch transplantation when administered during CABG surgery.

Predictors and clinical consequences of heart damage in CMR in patients after COVID-19

Abstract Methods Out-hospital clinic patients (pts) recovered from COVID-19 were prospectively recruited and underwent cardiac magnetic resonance (CMR) examination with a protocol including: edema, hyperemia, and necrosis or scar-derived from signal intensity assessment in T2-weighted, early gadolinium enhancement (EGE) and late gadolinium enhancement (LGE) CMR images. Results A total of 702 patients (mean age 50±12 years, 62% female) were included. The median (IQR) time interval between COVID-19 diagnosis and CMR was 13 (8–22) weeks. In none pts signs of edema, hyperemia and necrosis derived from signal intensity assessment in T2-weighted and early gadolinium enhancement was found. LGE was found in 152 (22%). LGE+ patients had significantly lower left ventricular (LV) ejection fraction (58.5±7.7 vs 61.1±7.9%, p&amp;lt;0.001) and greater LV end-diastolic (117.0±52.2 vs 103,0±36.3 ml, p=0.023) and end-systolic (50.3±28.0 vs 41.0±17.5 ml, p=0.010) volumes when compared with LGE− patients. In the resting electrocardiogram (ECG) fragmented QRS was observed significantly more frequently (46% vs 25%, p&amp;lt;0.001) in LGE+ group, whereas in 24h Holter ECG neither single premature, nor complex ventricular extrasystole burden did not differ between groups (p&amp;gt;0.05). There were observed no differences between symptoms of COVD-19 and comorbidities between LGE+ and LGE− pts. In the multivariable logistic regression analysis: fragmented QRS [OR and 95% CI: 2.85 (1.93–4.21)] and any ST-T segment deviation in resting ECG [OR: 1.93 (1.15–3.25)] were identified as independent predictors of LGE, even after adjustment for comorbidities and COVID-19 symptoms. Conclusions 1. In patients with fibrosis after COVID-19 reduced left ventricular ejection fraction and greater volume of the heart was found. 2. Fragmented QRS and ST-T abnormalities were independent predictors for LGE in patients after COVID-19. Funding Acknowledgement Type of funding sources: None.

Predicting arrhythmia recurrence following catheter ablation for ventricular tachycardia using late gadolinium enhancement magnetic resonance imaging: Implications of varying scar ranges.

Thresholding-based analysis of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) can create scar maps and identify corridors that might provide a reentrant substrate for ventricular tachycardia (VT). Current recommendations use a full-width-at-half-maximum approach, effectively classifying areas with a pixel signal intensity (PSI) >40% as border zone (BZ) and >60% as core. The purpose of this study was to investigate the impact of 4 different threshold settings on scar and corridor quantification and to correlate this with postablation VT recurrence. Twenty-seven patients with ischemic cardiomyopathy who had undergone catheter ablation for VT were included for retrospective analysis. LGE-CMR images were analyzed using ADAS3D LV. Scar maps were created for 4 PSI thresholds (40-60, 35-65, 30-70, and 45-55), and the extent of variation in BZ and core, as well as the number and weight of conduction corridors, were quantified. Three-dimensional representations were reconstructed from exported segmentations and used to quantify the surface area between healthy myocardium and scar (BZ + core), and between BZ and core. A wider PSI threshold was associated with an increase in BZ mass and decrease in scar (P <.001). No significant differences were observed for the total number of corridors and their mass with increasing PSI threshold. The best correlation in predicting arrhythmia recurrence was observed for PSI 45-55 (area under the curve 0.807; P = .001). Varying PSI has a significant impact on quantification of LGE-CMR parameters and may have incremental clinical value in predicting arrhythmia recurrence. Further prospective investigation is warranted to clarify the functional implications of these findings for LGE-CMR-guided ventricular ablation.

Magnetic resonance imaging and histopathology of catheter ablation lesions after ventricular tachycardia ablation in patients with nonischemic cardiomyopathy.

Late gadolinium enhanced cardiac magnetic resonance (LGE-CMR) imaging may help identify radiofrequency ablation lesions, which have been poorly described in patients with nonischemic cardiomyopathy (NICM). The purpose of this study was to describe LGE-CMR characteristics of ablation lesions in patients with NICM and correlate them with histopathology. Twenty-six patients (24 men; ejection fraction 38% ± 14%; age 61 ± 9 years) who had undergone CMR imaging after ventricular tachycardia (VT) ablation were included. Areas of both dark and bright core lesions correlating with previous radiofrequency ablation lesions were identified. Histology was performed on an explanted heart. Mean time between the ablation procedure and the LGE-CMR study was 8 [2-20] months. Twenty-three of 26 patients demonstrated dark core lesions (volume 2.16 ± 1.8 cm3; thickness 3.6 ± 1.3 mm) with transmurality of 42% ± 16% overlaying areas of intramural or transmural LGE. Fourteen of 26 patients demonstrated bright core lesions (volume 0.8 ± 0.6 cm3; depth 4.15 ± 1.76 mm) with transmurality of 34% ± 14%, which was located in areas without underlying LGE in 11 of 13 patients. Both dark and bright core lesions were visualized on standard clinical LGE-CMR imaging obtained in the acute setting and chronic settings (within 3 days and up to 2090 days postablation). Histopathologic analysis demonstrated coagulation necrosis in the area that corresponded to dark core lesions in the postablation CMR. Ablation lesions can be detected by LGE-CMR after VT ablation in NICM patients and have a different appearance than scar tissue. These lesions can be observed in the acute and chronic settings after ablations.

Cardiac segmentation on late gadolinium enhancement MRI: A benchmark study from multi-sequence cardiac MR segmentation challenge.

Accurate computing, analysis and modeling of the ventricles and myocardium from medical images are important, especially in the diagnosis and treatment management for patients suffering from myocardial infarction (MI). Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) provides an important protocol to visualize MI. However, compared with the other sequences LGE CMR images with gold standard labels are particularly limited. This paper presents the selective results from the Multi-Sequence Cardiac MR (MS-CMR) Segmentation challenge, in conjunction with MICCAI 2019. The challenge offered a data set of paired MS-CMR images, including auxiliary CMR sequences as well as LGE CMR, from 45 patients who underwent cardiomyopathy. It was aimed to develop new algorithms, as well as benchmark existing ones for LGE CMR segmentation focusing on myocardial wall of the left ventricle and blood cavity of the two ventricles. In addition, the paired MS-CMR images could enable algorithms to combine the complementary information from the other sequences for the ventricle segmentation of LGE CMR. Nine representative works were selected for evaluation and comparisons, among which three methods are unsupervised domain adaptation (UDA) methods and the other six are supervised. The results showed that the average performance of the nine methods was comparable to the inter-observer variations. Particularly, the top-ranking algorithms from both the supervised and UDA methods could generate reliable and robust segmentation results. The success of these methods was mainly attributed to the inclusion of the auxiliary sequences from the MS-CMR images, which provide important label information for the training of deep neural networks. The challenge continues as an ongoing resource, and the gold standard segmentation as well as the MS-CMR images of both the training and test data are available upon registration via its homepage (www.sdspeople.fudan.edu.cn/zhuangxiahai/0/mscmrseg/).

Assessment of left atrial fibrosis progression in canines following rapid ventricular pacing using 3D late gadolinium enhanced CMR images.

BackgroundAtrial fibrillation (AF) is associated with extracellular matrix (ECM) remodelling and often coexists with myocardial fibrosis (MF); however, the causality of these conditions is not well established.ObjectiveWe aim to corroborate AF to MF causality by quantifying left atrial (LA) fibrosis in cardiac magnetic resonance (CMR) images after persistent rapid ventricular pacing and subsequent AF using a canine model and histopathological validation.MethodsTwelve canines (9 experimental, 3 control) underwent baseline 3D LGE-CMR imaging at 3T followed by insertion of a pacing device and 5 weeks of rapid ventricular pacing to induce AF (experimental) or no pacing (control). Following the 5 weeks, pacing devices were removed to permit CMR imaging followed by excision of the hearts and histopathological imaging. LA myocardial segmentation was performed manually at baseline and post-pacing to permit volumetric %MF quantification using the image intensity ratio (IIR) technique, wherein fibrosis was defined as pixels > mean LA myocardium intensity + 2SD.ResultsVolumetric %MF increased by an average of 2.11 ± 0.88% post-pacing in 7 of 9 experimental dogs. While there was a significant difference between paired %MF measurements from baseline to post-pacing in experimental dogs (P = 0.019), there was no significant change in control dogs (P = 0.019 and P = 0.5, Wilcoxon signed rank tests). The median %MF for paced animals was significantly greater than that of non-paced dogs at the 5-week post-insertion time point (P = 0.009, Mann Whitney U test). Histopathological imaging yielded an average %MF of 19.42 ± 4.80% (mean ± SD) for paced dogs compared to 1.85% in one control dog.ConclusionPersistent rapid ventricular pacing and subsequent AF leads to an increase in LA fibrosis volumes measured by the IIR technique; however, quantification is limited by inherent image acquisition parameters and observer variability.

Simple Predictors for Cardiac Fibrosis in Patients with Type 2 Diabetes Mellitus: The Role of Circulating Biomarkers and Pulse Wave Velocity.

Cardiac fibrosis is the basis of structural and functional disorders in patients with diabetes mellitus (T2DM). A wide range of laboratory and instrumental methods is used for its prediction. The study aimed to identify simple predictors of cardiac fibrosis in patients with T2DM based on the analysis of circulating fibrosis biomarkers and arterial stiffness. The study included patients with T2DM (n = 37) and cardiovascular risk factors (RF, n = 27) who underwent ECHO, cardiac magnetic resonance imaging (MRI), pulse wave analysis (PWV), reactive hyperemia (RH), peripheral arterial tonometry, carotid ultrasonography, and assessment of serum fibrosis biomarkers. As a control group, 15 healthy subjects were examined. Left ventricular concentric hypertrophy was accompanied by an increased serum galectin-3 level in T2DM patients. There was a relationship between the PICP and HbA1c levels in both main groups (R2 = 0.309; p = 0.014). A negative correlation between PICP level and the global longitudinal strain (GLS) was found (r = −0.467; p = 0.004). The RH index had a negative correlation with the duration of diabetes (r = −0.356; p = 0.03), the carotid-femoral PWV (r = −0.371; p = 0.024), and the carotid intima-media thickness (r = −0.622; p < 0.001). The late gadolinium-enhanced (LGE) cardiac MRI was detected in 22 (59.5%) T2DM and in 4 (14.85%) RF patients. Diabetes, its baseline treatment with metformin, HbA1c and serum TIMP-1 levels, and left ventricle hypertrophy had moderate positive correlations with LGE findings (p < 0.05). Using the multivariate regression analysis, increased TIMP-1 level was identified as an independent factor associated with cardiac fibrosis.

Evaluation of combined late gadolinium-enhancement and functional cardiac magnetic resonance imaging using spiral real-time acquisition.

The purpose of the current study was to implement and validate joint real-time acquisition of functional and late gadolinium-enhancement (LGE) cardiac magnetic resonance (MR) images during free breathing. Inversion recovery cardiac real-time images with a temporal resolution of 50 ms were acquired using a spiral trajectory (IR-CRISPI) with a pre-emphasis based on the gradient system transfer function during free breathing. Functional and LGE cardiac MR images were reconstructed using a low-rank plus sparse model. Late gadolinium-enhancement appearance, image quality, and functional parameters of IR-CRISPI were compared with clinical standard balanced steady-state free precession breath-hold techniques in 10 patients. The acquisition of IR-CRISPI in free breathing of the entire left ventricle took 97 s on average. Bland-Altman analysis and Wilcoxon tests showed a higher artifact level for the breath-hold technique (p = 0.003), especially for arrhythmic patients or patients with dyspnea, but an increased noise level for IR-CRISPI of the LGE images (p = 0.01). The estimated transmural extent of the enhancement differed by not more than 25% and did not show a significant bias between the techniques (p = 0.50). The ascertained functional parameters were similar for the breath-hold technique and IR-CRISPI, that is, with a minor, nonsignificant (p = 0.16) mean difference of the ejection fraction of 2.3% and a 95% confidence interval from -4.8% to 9.4%. IR-CRISPI enables joint functional and LGE imaging in free breathing with good image quality but distinctly shorter scan times in comparison with breath-hold techniques.

Late gadolinium enhancement cardiac magnetic resonance imaging of ablation lesions after postinfarction ventricular tachycardia ablation: Implications for ventricular tachycardia recurrence.

Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging distinguishes between intrinsic postinfarction scar and radiofrequency ablation lesion related scar (dark core lesions [DCLs]) in patients with prior ventricular tachycardia (VT) ablation procedures. To combine LGE-CMR and electroanatomic mapping data to describe the relationship between DCLs and recurrent VT among patients undergoing repeat ablations for postinfarction VT. Consecutive patients with repeat ablation for postinfarct VT with LGE-CMR before the repeat procedures were studied. Prior ablation procedures and implantable cardiac defibrillator electrograms were analyzed to determine new versus previously documented VT. DCLs were identified on preprocedure LGE-CMR and registered to electroanatomic maps. A control group of patients undergoing repeat ablation procedures without imaging was included. Nineteen study patients and 14 control patients were followed for 2.6 (1.6-5.6) years (31 [94%] men, age 65.8 ± 8.4 years, ejection fraction 24.7 ± 10.3, p > 0.10 for all). DCLs corresponded to unexcitable tissue during repeat procedures (area 22.4 ± 15.1 vs. 22.9 ± 16.8 cm3 , correlation coefficient = .93). Most VT target sites (39/50 [78%]) were in close proximity (<1 cm) to DCLs. Most DCL related VTs 32/39 (82%) were new VTs. Patients with LGE-CMR imaging incorporated into their ablation procedures had improved 24-month survival from VT (64% vs. 38%, log rank p < 0.02). LGE-MRI can identify prior ablation lesions corresponding to nonexcitable tissue during repeat ablation procedures for postinfarction VT. VT target sites are often located in close proximity to the DCL area that may function as a fixed border for reentry circuits. Registration of DCL from prior ablation may facilitate repeat ablation procedures.

Effect of scar and pacing location on repolarization in a porcine myocardial infarction model.

BackgroundThe effect of chronic ischemic scar on repolarization is unclear, with conflicting results from human and animal studies. An improved understanding of electrical remodeling within scar and border zone tissue may enhance substrate-guided ablation techniques for treatment of ventricular tachycardia. Computational modeling studies have suggested increased dispersion of repolarization during epicardial, but not endocardial, left ventricular pacing, in close proximity to scar. However, the effect of endocardial pacing near scar in vivo is unknown.ObjectiveThe purpose of this study was to investigate the effect of scar and pacing location on local repolarization in a porcine myocardial infarction model.MethodsSix model pigs underwent late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging followed by electroanatomic mapping of the left ventricular endocardium. LGE-CMR images were registered to the anatomic shell and scar defined by LGE. Activation recovery intervals (ARIs), a surrogate for action potential duration, and local ARI gradients were calculated from unipolar electrograms within areas of late gadolinium enhancement (aLGE) and healthy myocardium.ResultsThere was no significant difference between aLGE and healthy myocardium in mean ARI (304.20 ± 19.44 ms vs 300.59 ± 19.22 ms; P = .43), ARI heterogeneity (23.32 ± 11.43 ms vs 24.85 ± 12.99 ms; P = .54), or ARI gradients (6.18 ± 2.09 vs 5.66 ± 2.32 ms/mm; P = .39). Endocardial pacing distance from scar did not affect ARI gradients.ConclusionOur findings suggest that changes in ARI are not an intrinsic property of surviving myocytes within scar, and endocardial pacing close to scar does not affect local repolarization.

QRS score: A simple marker to quantify the extent of myocardial scarring in patients with chronic total arterial occlusion

BackgroundChronic total occlusion (CTO) is a critical and unique subgroup of coronary lesions. This study aimed to investigate the correlation between the Selvester QRS score and late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMRI) in quantifying myocardial scarring to provide a simple and feasible method for treating CTO. MethodsThe medical records of 134 patients with absolute CTO who underwent coronary angiography between May 1, 2014 and December 30, 2017 were retrospectively reviewed. All patients were grouped according to the CTO location (RCA CTO, LAD CTO, LCX CTO, and multi-vessel CTO groups). The degree of myocardial scarring was determined according to the Selvester QRS score and using the LGE-CMRI. All patients were followed up for at least 12 months. ResultsAmong the 62 CTO patients, 55 had occlusion of a single vessel and seven had occlusion of multiple vessels, of which 27 (43.55%) were in the RCA CTO group, 16 (25.81%) in the LAD CTO group, 12 (19.35%) in the LCX CTO group, and 7 (11.29%) in the multi-vessel CTO group. The area under the receiver operating characteristic curve for the QRS score that was used to determine the degree of myocardial scarring was 0.806, with a sensitivity and specificity of 94.7% and 42.1%, respectively. The Selvester QRS score and LGE-CMRI measures of scar size were correlated in the RCA CTO, LCX CTO, and multi-vessel CTO groups (r = 0.466, 0.593, and 0.775, respectively). ConclusionThe Selvester QRS score was feasible for detecting myocardial scarring in patients with CTO.

Nonculprit Artery Myocardial Infarction and Complex Coronary Lesions in Anterior ST-Elevated Myocardial Infarction Patients: Data from the CIRCUS Study

Aims: Periprocedural myocardial infarctions have been reported in the setting of planned percutaneous coronary intervention (PCI). We assessed the prevalence of nonculprit artery acute myocardial infarction (NCAMI) and its relationship with coronary artery characteristics, final infarct size, and 1-year adverse clinical outcomes in a population of anterior ST-elevated myocardial infarction (STEMI) patients. Methods and Results: Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) studies were performed within 7 days of admission in 129 anterior STEMI patients from the CIRCUS trial treated by primary PCI. Infarct in the noninfarct artery territory (circumflex, right coronary) was assessed on LGE-CMR and T2-weighted images. Eleven (8.5%) patients exhibited NCAMI. The only independent characteristic significantly associated with NCAMI was the presence of multiple complex coronary lesions (odds ratio = 12.9, 95% confidence interval [3.1–53.4]; p < 0.001). There was a significantly increased infarct size in NCAMI patients compared to patients without NCAMI (45.8 ± 20.4% of the left ventricle [LV] vs. 31.0 ± 15.1% of LV, respectively; p = 0.02), with lower LV ejection fraction (46 ± 10% vs. 34 ± 8%, respectively; p < 0.001). Conclusion: NCAMIs are present in 8.5% of anterior STEMI patients and are significantly associated with multiple complex coronary lesions without significant relationship to any revascularization procedural technique. NCAMI was associated with a greater infarct size and reduced LVEF but not worse clinical outcomes at 1 year.