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Aims To non-invasively characterize, by means of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR), scar differences, and potential variables associated with ventricular tachycardia (VT) occurrence in chronic post-myocardial infarction (MI) patients. Methods and results A case–control study was designed through retrospective LGE-CMR data analysis of chronic post-MI patients (i) consecutively referred for VT substrate ablation after a first VT episode (n = 66) and (ii) from a control group (n = 84) with no arrhythmia evidence. The myocardium was characterized differentiating core, border zone (BZ), and BZ channels (BZCs) using the ADAS 3D post-processing imaging platform. Clinical and scar characteristics, including a novel parameter, the BZC mass, were compared between both groups. One hundred and fifty post-MI patients were included. Four multivariable Cox proportional hazards regression models were created for total scar mass, BZ mass, core mass, and BZC mass, adjusting them by age, sex, and left ventricular ejection fraction (LVEF). A cut-off of 5.15 g of BZC mass identified the cases with 92.4% sensitivity and 86.9% specificity [area under the ROC curve (AUC) 0.93 (0.89–0.97); P Conclusions The mass of BZC is the strongest independent variable associated with the occurrence of sustained monomorphic ventricular tachycardia in post-MI patients after adjustment for age, sex, and LVEF. Border zone channel mass measurement could permit a more accurate VT risk stratification than LVEF in chronic post-MI patients.

Aims Ventricular tachycardia (VT) substrate-based ablation has an increasing role in patients with structural heart disease-related VT. VT is linked to re-entry in relation to myocardial scarring with areas of conduction block (core scar) and areas of slow conduction [border zone (BZ)]. VT substrate can be analysed by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Our study aims to analyse the role of LGE-CMR in identifying predictors of VT recurrence after ablation. Methods and results We analysed 110 consecutive patients who underwent VT ablation from 2013 to 2018. All patients underwent a preprocedural LGE-CMR, and in 94 patients (85.5%), the CMR was used to aid the ablation. All LGE-CMR images were semi-automatically processed using dedicated software to detect scarring and conducting channels. After a median follow-up of 2.7 ± 1.6 years, the overall VT recurrence was 41.8% with an implantable cardioverter-defibrillator shock reduction from 43.6% to 28.2% before and after ablation, respectively. The amount of BZ (26.6 ± 13.9 vs. 19.6 ± 9.7 g, P = 0.012), the total amount of scarring (37.1 ± 18.2 vs. 29 ± 16.3 g, P = 0,033), and left ventricular (LV) mass (168.3 ± 53.3 vs. 152.3 ± 46.4 g, P Conclusion Pre-procedural LGE-CMR is a helpful and feasible technique to identify patients with high risk of VT recurrence after ablation. LV mass, septal LGE distribution, and transmural channels were predictive factors of post-ablation VT recurrence.

Aims Ventricular tachycardia (VT) substrate-based ablation has become a standard procedure. Electroanatomical mapping (EAM) detects scar tissue heterogeneity and define conduction channels (CCs) that are the ablation target. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is able to depict CCs and increase ablation success. Most patients undergoing VT ablation have an implantable cardioverter-defibrillator (ICD) that can cause image artefacts in LGE-CMR. Recently wideband (WB) LGE-CMR sequence has demonstrated to decrease these artefacts. The aim of this study is to analyse accuracy of WB-LGE-CMR in identifying the CC entrances. Methods and results Thirteen consecutive ICD-patients who underwent VT ablation after WB-LGE-CMR were included. Number and location of CC entrances in three-dimensional EAM and in WB-LGE-CMR reconstruction were compared. Concordance was compared with a historical cohort matched by cardiomyopathy, scar location, and age (26 patients) with LGE-CMR prior to ICD and VT ablation. In WB-CMR group, 101 and 93 CC entrances were identified in EAM and WB-LGE-CMR, respectively. In historical cohort, 179 CC entrances were identified in both EAM and LGE-CMR. The EAM/CMR concordance was 85.1% and 92.2% in the WB and historical group, respectively (P = 0.66). There were no differences in false-positive rate (CC entrances detected in CMR and absent in EAM: 7.5% vs 7.8% in WB vs. conventional CMR, P = 0.92) nor in false-negative rate (CC entrances present in EAM not detected in CMR: 14.9% vs.7.8% in WB vs. conventional CMR, P = 0.23). Epicardial CCs was predictor of poor CMR/EAM concordance (OR 2.15, P = 0.031). Conclusion Use of WB-LGE-CMR sequence in ICD-patients allows adequate VT substrate characterization to guide VT ablation with similar accuracy than conventional LGE-CMR in patients without an ICD.

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This work was supported by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” Background. Cardiovascular magnetic resonance (CMR) is the best tool for left ventricular ejection fraction (LVEF) quantification, but as yet the prognostic value of sequential LVEF assessment for major adverse cardiac event (MACE) prediction after ST-segment elevation myocardial infarction (STEMI) is uncertain. Purpose. We explored the prognostic impact of sequential assessment of CMR-derived LVEF after STEMI to predict subsequent MACE. Methods. We recruited 1036 STEMI patients in a large multicenter registry. LVEF (reduced [r]: 3 months of follow-up. MACE was regarded as cardiovascular death or re-admission for acute heart failure after follow-up CMR. Results. During a 5.7-year mean follow-up, 82 MACE (8%) were registered. The MACE rate was higher only in patients with LVEF Conclusions. LVEF constitutes a pivotal CMR index for simple and dynamic post-STEMI risk stratification. Detection of reduced LVEF (

Funding Acknowledgements Type of funding sources: None. Introduction Myocardial T1 mapping constitutes a reliable indicator of heart diseases related to changes of myocardial extracellular content (e.g. oedema, fibrosis) as well as fat, iron and amyloid content. T1-mapping techniques rely on fitting a model to a series of MRI measurements. Alignment between these measurements is required for accurate T1 estimation. This is limited by triggering accuracy and patient motion. Image registration is often applied to improve the alignment. In the case of MOLLI series, registration is compromised by contrast variation between the images. We present the validation of a new registration method, designed to account for the contrast properties of MOLLI data. Methods A cohort of 186 patients referred for a CMR was included in this study (115 M / 71 F; weight 75 ± 15 Kg; age 55 ± 16). Scans on a 3.0T MR included a MOLLI sequence with target parameters: 2D bSSFP, 160x148, pFOV 0.8-1.0, 1.4x1.4mm², ST 8mm, TE 1.4ms, TR 3.0ms, FA 35deg, NEX 1, BW 100kHz, 2x ASSET, 5(3)3. Cartesian 2D reconstruction followed by motion correction was applied retrospectively. A new correction algorithm was implemented, based on a similarity criterion that accounted for T1 relaxation: It consisted of an iterative approach alternating polarity estimation, T1 fitting, relaxation simulation and frame registration. The coefficient of determination (R²) was used as a quality measure. A representative subset of the results was reviewed by two experienced cardiologists. Results All reconstructions (totalling 1133 2D MOLLI series) yielded qualitatively correct T1 maps. Results with the new method were compared to conventional motion correction and no correction. The number of pixels with R²>0.95 was 85%±9% with standard motion correction and 90%±7% with the new dedicated method. In terms of improvement w.r.t. uncorrected data, the standard method yielded +3%±8% and the new one +9%±8%. Motion correction caused noticeable performance degradation in 12% of cases with the standard method, compared to 0.2% with the proposed method. The relative performance of the different methods can be appreciated in Figure 3. Discussion Despite T1 mapping techniques constituting a reliable diagnostic tool in cardiac imaging, they remain sensitive to patient motion and triggering inaccuracies, making them vulnerable to arrhythmia episodes. Improving the similarity criterion by accounting for T1 relaxation significantly decreased the incidence of misregistration and subsequent T1 inaccuracies. Using the R² of the voxel-wise T1 fit as a surrogate of alignment allowed to confirm the increased robustness of the new, dedicated motion correction method for MOLLI series. Conclusion We have demonstrated a new reconstruction pipeline with built-in registration, optimized for MOLLI T1-mapping. Using a large database of clinical data, the new method has been shown to improve the robustness to motion of cardiac T1 mapping. Abstract Figure.

Funding Acknowledgements Type of funding sources: None. Introduction Myocardial delayed enhancement (MDE) MRI plays an important role in the identification of several cardiac conditions, both ischemic and non-ischemic (e.g. myocarditis, IDC, amyloidosis). 3D imaging offers increased resolution, full heart coverage and better depiction of complex pathologies, but its image quality is limited by long acquisition times. Deep learning (DL) models enable advanced reconstruction algorithms that yield regularized images in practical computation times. In this study we evaluate a novel 3D-DL reconstruction to overcome the trade-off between reconstructed quality and acquisition time on MDE data. Methods A group of 14 subjects referred for CMR (5 F / 9 M, 59 ± 11 y.o., 78 ± 13 kg) were scanned with a 3D MDE sequence prototype: SPGR with IR preparation, fat & spatial saturation, respiratory navigator, ARC 2x, FOV 40x40cm, ST 1.4-2.4mm, matrix 280²-320², FA 20deg, BW 62.5 kHz, TE 2.1 ± 0.1ms, TI based on a CINE IR scout. All were retrospectively reconstructed using a 3D DL algorithm, trained on a database of over 700 datasets to reconstruct high-quality images with adjustable noise reduction. The images were compared with standard 3D Cartesian reconstruction by two experienced cardiologists, to identify alterations in morphology or contrast distribution. Noise was estimated using the intensity standard deviation on a blood pool ROI. Feature preservation was estimated using the structural similarity index (SSI). Results The new method improved perceived image quality without loss of structural information or resolution (fig 1). Quantitative analysis (fig 2) confirmed these results: The average coefficient of variation in the blood was 0.08 ± 0.02 in the reference and 0.05 ± 0.02 with the new method; Given a target image noise level, DL reconstruction yielded up to 10% better SSI, compared to anisotropic filtering. The clinical review didn’t reveal diagnostically significant alterations of structure or uptake pattern. A perceived reduction of sharpness was initially reported but individual examination of landmarks (e.g. pulmonary and coronary arteries) confirmed that no relevant features were being lost with the new reconstruction. Discussion The 3D MDE images obtained with DL reconstruction improved the trade-off between image noise -estimated by the blood pool intensity deviation- and feature preservation -estimated by SSI-. Consistent improvement of image quality without morphological alterations of diagnostic relevance indicates that the new method can be considered for clinical practice. The next step in the validation process will require testing the robustness over a large set of cases with heterogeneous acquisition settings. Conclusion We presented the preliminary evaluation of a deep learning reconstruction method with 3D myocardial delayed enhancement data. The results show systematic improvement of overall image quality without loss of relevant diagnostic information. Abstract Figure.

Aims Left ventricular (LV) outflow tract ventricular arrhythmias (OTVA) are associated with hypertension (HT), older age, and LV dysfunction, suggesting that LV overload plays a role in the aetiopathogenesis. We hypothesized that anatomical modifications of the LV outflow tract (LVOT) could predict left vs. right OTVA site of origin (SOO). Methods and results Fifty-six (32 men, 53 ± 18 years old) consecutive patients referred for OTVA ablation were included. Cardiac multidetector computed tomography was performed before ablation and then imported to the CARTO system to aid the mapping and ablation procedure. Anatomical characteristics of the aortic root as well as aortopulmonary valvular planar angulation (APVPA) were analysed. The LV was the OTVA SOO (LVOT-VA) in 32 (57%) patients. These patients were more frequently male (78% vs. 22%, P = 0.001), older (57 ± 18 vs. 47 ± 18 years, P = 0.055), and more likely to have HT (59% vs. 21%, P = 0.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68 ± 5° vs. 55 ± 6°, respectively; P

Background: Serum soluble AXL (sAXL) and its ligand, Growth Arrest-Specific 6 protein (GAS6), intervene in tissue repair processes. AXL is increased in end-stage heart failure, but the role of GAS6 and sAXL in ST-segment elevation myocardial infarction (STEMI) is unknown. Objectives: To study the association of sAXL and GAS6 acutely and six months following STEMI with heart failure and left ventricular remodelling. Methods: GAS6 and sAXL were measured by enzyme-linked immunosorbent assay at one day, seven days and six months in 227 STEMI patients and 20 controls. Contrast-enhanced magnetic resonance was performed during admission and at six months to measure infarct size and left ventricular function. Results: GAS6, but not sAXL, levels during admission were significantly lower in STEMI than in controls. AXL increased progressively over time ( p1) had higher values of sAXL at day 1 (48.9±11.9 vs. 44.0±10.7 ng/ml; pConclusion: sAXL levels increased following STEMI. Patients with heart failure and left ventricular remodelling have higher sAXL levels acutely and at six month follow-up. These findings suggest a potential role of the GAS6–AXL system in the pathophysiology of left ventricular remodelling following STEMI.

Aims Non-invasive depiction of conducting channels (CCs) is gaining interest for its usefulness in ventricular tachycardia (VT) ablation. The best imaging approach has not been determined. We compared characterization of myocardial scar with late-gadolinium enhancement cardiac magnetic resonance using a navigator-gated 3D sequence (3D-GRE) and conventional 2D imaging using either a single shot inversion recovery steady-state-free-precession (2D-SSFP) or inversion-recovery gradient echo (2D-GRE) sequence. Methods and results We included 30 consecutive patients with structural heart disease referred for VT ablation. Preprocedural myocardial characterization was conducted in a 3 T-scanner using 2D-GRE, 2D-SSFP and 3D-GRE sequences, yielding a spatial resolution of 1.4 × 1.4 × 5 mm, 2 × 2 × 5 mm, and 1.4 × 1.4 × 1.4 mm, respectively. The core and border zone (BZ) scar components were quantified using the 60% and 40% threshold of maximum pixel intensity, respectively. A 3D scar reconstruction was obtained for each sequence. An electrophysiologist identified potential CC and compared them with results obtained with the electroanatomic map (EAM). We found no significant differences in the scar core mass between the 2D-GRE, 2D-SSFP, and 3D-GRE sequences (mean 7.48 ± 6.68 vs. 8.26 ± 5.69 and 6.26 ± 4.37 g, respectively, P = 0.084). However, the BZ mass was smaller in the 2D-GRE and 2D-SSFP than in the 3D-GRE sequence (9.22 ± 5.97 and 9.39 ± 6.33 vs. 10.92 ± 5.98 g, respectively; P = 0.042). The matching between the CC observed in the EAM and in 3D-GRE was 79.2%; when comparing the EAM and the 2D-GRE and the 2D-SSFP sequence, the matching decreased to 61.8% and 37.7%, respectively. Conclusion 3D scar reconstruction using images from 3D-GRE sequence improves the overall delineation of CC prior to VT ablation.

Aims The endocardial vs. epicardial origin of ventricular arrhythmia (VA) can be inferred from detailed electrocardiogram (ECG) analysis. However, despite its clinical usefulness, ECG has limitations. Alternatively, scarred tissue sustaining VAs can be identified by contrast-enhanced cardiac magnetic resonance (ce-CMR). The objective of this study was to determine the clinical value of analysing the presence and distribution pattern of scarred tissue in the ventricles to identify the VA site of origin and the ablation approach required. Methods and results A ce-CMR study was carried out before the index ablation procedure in a cohort of 80 patients with non-idiopathic VA. Hyper-enhancement (HE) in each ventricular segment was coded as absent, subendocardial, transmural, mid-myocardial, or epicardial. The endocardial or epicardial VA site of origin was also assigned according to the approach needed for ablation. The clinical VA was successfully ablated in 77 (96.3%) patients, all of them showing HE on ce-CMR. In segments with successful ablation of the clinical ventricular tachycardia, HE was absent in 3 (3.9%) patients, subendocardial in 19 (24.7%), transmural in 36 (46.7%), mid-myocardial in 8 (10.4%), and subepicardial in 11 (14.3%) patients. Epicardial ablation of the index VA was necessary in 3 (6.1%) ischaemic and 12 (42.9%) non-ischaemic patients. The presence of subepicardial HE in the successful ablation segment had 84.6% sensitivity and 100% specificity in predicting an epicardial origin of the VA. Conclusion Contrast-enhanced cardiac magnetic resonance is helpful to localize the target ablation substrate of non-idiopathic VA and also to plan the approach needed, especially in non-ischaemic patients.

Aims There is insufficient evidence to implant a combined cardiac resynchronization therapy (CRT) device with defibrillation capabilities (CRT-D) in all CRT candidates. The aim of the study was to assess myocardial scar size and its heterogeneity as predictors of sudden cardiac death (SCD) in CRT candidates. Methods and results A cohort of 78 consecutive patients with dilated cardiomyopathy and class I indication for CRT-D were prospectively enrolled. Before CRT-D implantation, a contrast-enhanced cardiac magnetic resonance (ce-CMR) was performed. The core and border zone (BZ) of the myocardial scar were characterized and quantified with a customized post-processing software. The first appropriate implantable cardioverter defibrillator (ICD) therapy was considered as a surrogate of SCD. During a mean follow-up of 25 months (25–75th percentiles, 15–34), appropriate ICD therapy occurred in 11.5% of patients. In a multivariate Cox proportional hazards regression model for clinical and ce-CMR variables, the scar mass percentage [hazards ratio (HR) per 1% increase 1.1 (1.06–1.15), P < 0.01], the BZ mass [HR per 1 g increase 1.06 (1.04–1.09), P < 0.01], and the BZ percentage of the scar [HR per 1% increase 1.06 (1.02–1.11), P < 0.01], were the only independent predictors of appropriate ICD therapy. Receiver-operating characteristic curve analysis showed that a scar mass

Aims To assess the short- and long-term effects of postconditioning (p-cond) on infarct size, extent of myocardial salvage, and left ventricular ejection fraction (LVEF) in a series of patients presenting with evolving ST-elevation myocardial infarction (STEMI). Previous studies have shown that p-cond during primary percutaneous coronary intervention (PCI) confers protection against ischaemia–reperfusion injury and thus might reduce myocardial infarct size. Methods and results Seventy-nine patients undergoing PCI for a first STEMI with TIMI grade flow 0–1 and no collaterals were randomized to p-cond ( n = 39) or controls ( n = 40). Postconditioning was performed by applying four consecutive cycles of 1 min balloon inflation, each followed by 1 min deflation. Infarct size, myocardial salvage, and LVEF were assessed by cardiac-MRI 1 week and 6 months after MI. Postconditioning was associated with lower myocardial salvage (4.1 ± 7.2 vs. 9.1 ± 5.8% in controls; P = 0.004) and lower myocardial salvage index (18.9 ± 27.4 vs. 30.9 ± 20.5% in controls; P = 0.038). No significant differences in infarct size and LVEF were found between the groups at 1 week and 6 months after MI. Conclusion This randomized study suggests that p-cond during primary PCI does not reduce infarct size or improve myocardial function recovery at both short- and long-term follow-up and might have a potential harmful effect.

Introduction: Delayed enhanced cardiac magnetic resonance using 2D sequences (CMR-2D) represents the standard for clinical characterization of myocardium. However, 2D images suffer from insufficient spatial resolution in the Z-axis and missregistration that preclude appropriate visualization of conducting channels (CC), which are critical for ventricular tachycardia (VT) ablation. We studied whether characterization using a free breathing 3D delayed enhanced navigator gated sequence (CMR-3D) proved to be superior than CMR-2D sequences. Methods: We included 30 consecutive patients with structural heart disease referred for VT ablation. Myocardial characterization was conducted prior to the ablation procedure in a 3T-scanner using CMR-2D and CMR-3D sequences, yielding a spatial resolution of 1.4 x 1.4 x 5 mm and 1.4 x 1.4 x 1.4 mm respectively. The scar components, core and border zone (BZ), were quantified in both datasets using the 60% and 40% threshold of maximum pixel intensity, respectively. The signal to noise ratio (SNR) and contrast to noise ratio (CNR) was analyzed in a representative slice in both sequences. For both set of images a 3D reconstruction of the scar was obtained and an electrophysiologyst identified potential CC and compared them to those depicted in the electroanatomic map (EAM). Results: We found no significant differences between the mass of the scar core in the 2D and 3D sequence (mean 7.33±6.56 vs 6.74±5.22 grams respectivelly, p=0.612). However, the BZ mass was smaller in the 2D than in the 3D sequence (9.38±7.72 vs 12.10±7.81 grams; p=0.019). The SNR was higher in the 2D dataset as compared to the 3D (42.93±27.34 vs 28.09±12.85; p=0.005) as well as the CNR (37.01±26.20 vs 20.15±11.41; p=0.001). The mean number of CC identified in the 3D dataset was higher than in the 2D, and closer to those depicted in the EAM (1.06±0.75 for CMR-2D vs 2.63±1.41 for EAM, p=0.005; and 2.06±1.25 for CMR-3D vs 2.63±1.41 for EAM p=0.088). Conclusion: Despite the higher SNR and CNR of standard CMR-2D images, the higher spatial resolution provided by CMR-3D images improved the overall delineation of CC prior to VT ablation.