Late Gadolinium Enhancement Volume Research Articles

Cardiovascular magnetic resonance 3D LGE imaging for atrial fibrillation ablation

Abstract Objective To assess feasibility and reliability of cardiac magnetic resonance (CMR) imaging in visualizing left atrial (LA) structural changes that patients with paroxysmal atrial fibrillation (PAF) undergo acutely and long-term post ablation. Two different ablation methods i.e pulsed filed ablation (PFA) and cryoablation were studied. Background Pulmonary vein (PV) isolation has become the cornerstone technique for catheter ablation in patients with drug-refractory atrial fibrillation (AF). At present, almost all ablation technologies are mediated by a thermal effect. Recently, pulsed field ablation (PFA) has been introduced as a new energy source. PFA is a non-thermal ablative modality in which high voltage ultra-short pulses are applied to target tissue, while preserving the extracellular matrix architecture, nerves, and microvascular structures. Few data exist showing different structural LA changes between the two methods using Three-Dimensional (3D) Late Gadolinium Enhancement (LGE) Imaging. Methods CMR imaging was performed pre-ablation, acutely (<24 h), and 3 months post-ablation in 10 patients with paroxysmal atrial fibrillation (AF) undergoing pulmonary vein (PV) isolation with PFA (n = 5) or cryoablation (n = 5). 3D LGE and T2-weighted images were analysed. We obtained two data sets of 3D whole heart LGE imaging with high resolution, 20minutes post gadolinium injection. 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 LGE with Dixon water-fat separation. 3D LGE data were analysed using a dedicated (ADAS LA) software in order to produce a 3D-LA model visualization of LGE areas. Results In the acute stage, LGE volume was 50% larger after PFA vs. cryoablation (P < 0.001), and oedema on T2 imaging was significantly smaller (visual estimation) on PFA cases. LGE rings surrounding PV ostia were more homogeneous after PFA, with no sign of microvascular damage or intramural hemorrhage as compared to cryoablation cases. In the chronic stage, the majority of acute LGE had disappeared after PFA, whereas most LGE persisted after cryo-ablation. The two 3D LGE sequences used for analysis showed complete agreement in the visualization of atrial scar with superior image quality of the novel sequence. The 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. Conclusions CMR imaging may help in visualization and understanding of LA structural remodeling post different ablation techniques.

Early diagnostic and prognostic value of myocardial strain derived from cardiovascular magnetic resonance in patients with cardiac amyloidosis.

Cardiac amyloidosis (CA) is one of the causes of heart failure with preserved ejection fraction. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume (ECV) fractions is a preferred method to identify CA. However, the requirement of contrast limits its use in renal deficiency patients. Myocardial strain is a promising method without contrast. We sought to assess the early diagnostic and prognostic value of strain. This retrospective study enrolled 31 patients with systemic amyloidosis (SA) in Peking University First Hospital from January 2014 to January 2019. The patients were categorized into three groups, including 11 CA patients with left ventricular hypertrophy (CA-LVH group), 9 CA patients without LVH (CA-NLVH group), and 11 patients with extracardiac SA (SA group). Strain analysis was performed with CMR images. A least absolute shrinkage and selection operator (LASSO) was used to generate strain score. The receiver operating characteristic (ROC) curve was used to evaluate the early diagnostic efficacy of strain score and other single strain parameter. The primary endpoint was defined as death from all cause or rehospitalization for heart failure. A Cox proportional hazards model was used to assess the index value on the prognosis. In CA patients, as the left ventricular wall thickens, the global and regional strain decrease significantly. A new strain score (strain score = 0.00893 × mid-septal circumferential peak strain + 0.02285 × apical radial peak strain + 0.1541 × apical circumferential peak strain + 0.33097 × epicardial circumferential average peak strain + 0.42232 × endocardial longitudinal average peak strain) generated using LASSO showed that the area under the ROC curve was 0.909. All the patients with outcome events were in CA groups, four were in CA-LVH group and one in CA-NLVH group. New York Heart Association (NYHA) grade [hazard ratio (HR) =14.29, 95% confidence interval (CI): 2.34-87.34, P<0.01], brain natriuretic peptide (HR =20.05, 95% CI: 2.21-182.36, P=0.008), cardiac injury biomarker (HR =11.59, 95% CI: 1.03-130.36, P=0.047), E/E' (mitral inflow to mitral relaxation velocity ratio) (HR =1.09, 95% CI: 1.00-1.18, P=0.040), end-systolic left ventricular volume (HR =1.04, 95% CI: 1.00-1.18, P=0.039) and LGE volume (HR =1.11, 95% CI: 1.02-1.20, P=0.012) positively correlate with events. Better renal function (HR =0.92, 95% CI: 0.86-0.98, P=0.011) and ejection fraction (HR =0.94, 95% CI: 0.88-0.99, P=0.027) appear to be protective factors. Although with no statistical difference, the strain damage had a tendency to predict poor prognosis, i.e., mid-ventricular circumferential strain with HR of 1.25 (95% CI: 1.0-1.57, P=0.050) and strain score with HR of 1.30 (95% CI: 0.98-1.73, P=0.067). Myocardial strain decreased in CA patients. The integrated magnetic resonance imaging (MRI) strain score can serve as a useful tool to identify early myocardial involvement in amyloidosis. The strain damage had a tendency to predict poor prognosis.

Quantitative Analysis of Radiation Therapy-Induced Cardiac and Aortic Sequelae in Patients With Lung Cancer via Magnetic Resonance Imaging: A Pilot Study

PurposeTo quantify early radiotherapy (RT)-induced cardiac and aortic changes in patients with lung cancer using cardiac MRI. Methods and MaterialsNine patients with lung cancer treated with RT completed MR scans at baseline (before RT), 3 months, and 6 months following RT. Cine, T1/T2, late gadolinium enhancement (LGE), and 4D-flow MRIs were acquired to assess biological and mechanical cardiovascular changes globally (i.e., over the entire left ventricle (LV) or aorta) and regionally (according to an American Heart Association model). ResultsRegional metrics demonstrated multiple significant changes and dose-dependent responses. Notably, LGE showed changes at 3 and 6 months over septal and high-dose regions (P<0.0458). Longitudinal strain changes were notable at septal and high-dose regions at 3 months and septal regions at 6 months (P<0.0469). Elevated T1/T2 signals (P<0.0391) and changes in radial/circumferential strain at the septum (P<0.0391) were observed at 3 months. Both T1/T2 signal and LGE were correlated with dose at 6 months (T1 signal also at 3 months), with significantly greater changes in regions receiving >50 Gy (P<0.0331). LV dose was not correlated with LV strain changes (P>0.1), but ascending aortic dose was correlated with strain changes at segments 1 and 2 of the LV (P<0.0362). Global metrics identified only two significant responses: increase in LGE volume at 6 months and a reduction in ascending aortic circumferential strain at 3 months (P<0.0356). ConclusionEarly MR-based changes following RT occurred primarily in high-dose regions and the LV septal wall. While several early signals resolved by 6 months, LGE and longitudinal strain changes persisted for at least 6 months. Dose-dependent responses/correlations were observed for T1/T2/LGE changes at 6 months, with the greatest effect in regions exposed to >50 Gy. Further investigations with larger cohorts and longer follow-up are warranted to confirm regional dose dependence and the association between aortic dose and LV strain observed in this pilot study.

Prognostic implications of unrecognized myocardial infarction and periprocedural myocardial injury on cardiac magnetic resonance imaging in patients with chronic coronary syndrome

This study sought to evaluate the prognostic implications of the presence of preprocedural unrecognized myocardial infarction (UMI) and periprocedural myocardial injury (PMI) evaluated by delayed gadolinium enhancement cardiac magnetic resonance (DE-CMR) in patients with chronic coronary syndrome (CCS) undergoing elective percutaneous coronary intervention (PCI). We enrolled 250 CCS patients scheduled for elective PCI. UMI was defined as the presence of late gadolinium enhancement (LGE) detected by pre-PCI CMR in the region without medical history of revascularization and/or MI. Periprocedural new occurrence or increased volume of LGE in the target territory detected by post-PCI CMR (PPL) were used to assess PMI. In the final analysis of 235 patients, UMI and PPL were detected in 43 patients (18.3%) and 45 patients (19.1%), respectively. During follow-up for a median of 2.2 years, major adverse cardiac events (MACE) occurred in 31 (13.2%) patients. On multivariable analysis, UMI and PPL remained as significant predictors of MACE after adjusting confounding factors (HR 4.62, 95% CI 2.24–9.54, P < 0.001, HR 2.33, 95% CI 1.11–4.91, P = 0.026). In patients with CCS who underwent elective PCI, UMI and PPL were independent predictors of worse outcomes. UMI and PPL on DE-CMR might provide additional potential insight for the risk stratification of patients undergoing elective PCI.

Assessment of Myocardial Viability and Risk Stratification in Coronary Chronic Total Occlusion: A Qualitative and Quantitative Stress Cardiac MRI Study.

Indicators for assessing myocardial viability and risk stratification in patients with coronary chronic total occlusion (CTO) are still in the research stage. To use stress-MRI to assess myocardial function, blood perfusion, and viability and to explore their relationship with collateral circulation. Prospective. Fifty-one patients with CTO in at least one major artery confirmed by X-ray coronary angiography (male: 46; age 55.2 ± 10.8 years). 3.0T; TurboFlash, balanced steady-state free precession cine, and phase-sensitive inversion recovery sequences. Stress-MRI was used to obtain qualitative and quantitative parameters of segmental myocardium. Myocardial segments supplied by CTO target vessels were grouped according to the degree of collateral circulation assessed by radiographic coronary angiography (no/mild, moderate, or good). Depending on qualitative stress perfusion assessment and late gadolinium enhancement (LGE) extent, segments were also categorized as negative, viable, or trans-infarcted. Independent sample Student's t-test, one-way analysis of variance (ANOVA) test, Mann-Whitney U test, Kruskal-Wallis test, Spearman correlation coefficient (r). P < 0.05 was considered statistically significant. A total of 334 segments were supplied by CTO target vessels. The radial strain (RS), circumferential strain (CS), longitudinal strain (LS) of the negative, viable, and trans-infarcted regions showed a significant and stepwise impairment. Myocardial blood flow at rest was positively correlated with RS, CS, and LS (r = 0.42, 0.43, 0.38, respectively). Among the different collateral circulation, there were no significant differences in RS, CS, LS, and LGE volume (P = 0.788, 0.562, 0.122, 0.170, respectively), and there were also no statistically significant differences in the proportions of negative, viable, and trans-infarcted regions (P = 0.372). Myocardial perfusion obtained by stress-MRI combined with strain and LGE may comprehensively evaluate myocardial function and viability, and has potential to facilitate risk stratification of CTO. 2 TECHNICAL EFFICACY: Stage 1.

The predictive role of right ventricular late gadolinium enhancement in patients with tetralogy of Fallot undergoing pulmonary valve replacement

BackgroundOur purpose was to evaluate the correlations between right ventricular (RV) late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) in patients with tetralogy of Fallot (ToF) scheduled for pulmonary valve replacement (PVR) and post-PVR functional data.MethodsWe retrospectively reviewed ToF patients scheduled for PVR who underwent two CMR examinations at our institution, one before the procedure (CMR-0), including contrast-enhanced sequences, and one after the procedure (CMR-1). Functional left and RV data were obtained by segmenting short-axis stacks on both CMR examinations, and normalised variations were calculated by dividing differences between CMR-1 and CMR-0 by the intercurring time interval, whereas the RV scar burden was assessed on CMR-0 LGE sequences both semiquantitatively and quantitatively. Data were reported as median and interquartile range, differences were appraised with the Mann–Whitney U test, while correlations were assessed with Spearman’s ρ.ResultsFifteen patients with a median age of 25 years (16–29), including 9 (60%) males, with a median time interval between CMR-0 and CMR-1 of 17 months (12–23), were retrospectively reviewed. The semiquantitative LGE score at CMR-0 was 7 (6–9), and LGE volume was 4.49 mL (3.70–5.78), covering 5.63% (4.92–7.00) of the RV. RV LGE score showed a moderate positive correlation with the normalised variation of RV stroke volume (ρ = 0.662, p = 0.007) and a borderline moderate positive correlation with the normalised variation of RV end-diastolic indexed volume (ρ = 0.513, p = 0.050).ConclusionsThe assessment of RV LGE before PVR may provide insights on post-PVR functional data, potentially facilitating a patient-tailored treatment pathway.

Abstract 9395: Natural History of Myocardial Injury Following Covid-19 Vaccine Associated Myocarditis

Introduction: Acute myocarditis is a rare complication of mRNA-based COVID-19 vaccination. The natural history and clinical sequalae of this complication are of critical importance to estimate the impact on population health. Objective: To study the impact of COVID-19 vaccine associated myocarditis on convalescent myocardial health, symptoms, and clinical outcomes. Methods: This study was performed at two tertiary care hospitals. Baseline and convalescent (≥3 month) CMR imaging was performed for 20 consecutive patients meeting Updated Lake Louise Criteria for acute myocarditis within 10 days of mRNA-based vaccination and with no evidence of active viral infection. Global and segmental CMR-based markers of myocardial injury were studied at baseline and convalescence, inclusive of chamber volumetry, LV ejection fraction (LVEF), LV mass, T1 and T2 mapping, late gadolinium enhancement (LGE) imaging, and extracellular volume (ECV) fraction. Major clinical outcomes were captured. Results: The median age was 23.1 years (range 18-39 years) with 17 (85%) being male. Convalescent CMR evaluations were performed at a median (IQR) of 3.7 (3.3-6.2) months. Five patients (25%) had a baseline LVEF &lt;50%. All patients showed abnormal LGE inclusive of a sub-epicardial pattern with a mean LGE burden of 8.6+/-5.3% LV mass using a &gt;5SD of reference threshold. At follow-up, a mean 3% absolute improvement in LVEF was observed, accompanied by a 7% reduction in LVEDV and 5% reduction in LV mass (all p&lt;0.015). Global LGE volume reduced by 66% (p&lt;0.001). Absolute reductions in global T2, native T1, and ECV of 2.1msec, 58msec, and 2.9%, respectively were documented (all p≤0.001). All patients with LVEF &lt;50% at baseline recovered above this threshold. However, 18 (90%) patients showed persistence of LGE at follow-up with 15% having a burden &gt;5% of the LV mass. No patient experienced major clinical outcomes. Conclusion: COVID-19 mRNA vaccine associated myocarditis shows rapid improvement in CMR-based markers of tissue edema, contractile function, and LGE, and was not associated with adverse events at intermediate range follow-up. However, convalescent fibrosis was commonly observed, justifying ongoing need for clinical surveillance in this population.

Preliminary data on a fully automated left ventricular late gadolinium enhancement detection by a convolutional neuronal network in chronic myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): FWF- Der Wissenschaftsfonds Aim To compare a fully automated segmentation of left ventricular late gadolinium enhancement (LGE) as evaluated by a convolutional neuronal network (CNN) with manual segmentation in chronic myocardial infarction. Methods Cardiac magnetic resonance imaging including two-dimensional LGE imaging was performed in 191 patients on a 1.5 T clinical scanner 12 months after ST-elevation myocardial infarction. LGE images were presented to a trained CNN for automated determination of left ventricular myocardium and consequently absolute LGE volume. Manual LGE segmentation according to the +5-SD method was used as reference standard. Image quality was assessed according to a 3-point Likert scale (2 = perfect image quality, 1 = some artifacts witout impaired LGE delineation, 0 = strong artifacts with impaired LGE delineation). Regression and Bland-Altman analysis were performed. Results In 191 included patients (182 male, mean age 57 years) LGE volume was 9.7 [IQR 3.6 to 16.2] ml according to manual segmentation and 8.3 [3.2 to 17.6] ml according to CNN segmentation. Bland-Altman analysis showed little average difference (-0.5 ml, p=0.257), however, limits of agreement ranged from -18.4 ml to 17.5 ml. Linear correlation was fair (0.57, p&amp;lt;0.001). Subgroup analysis according to image quality showed comparable performance of CNN segmentation in all three groups. Conclusion Our fully automated LGE segmentation based on a CNN in two-dimensional data sets provides measurements with little average difference compared to very time-consuming manual segmentations. However, dispersion is substantially and limits the current application of this approach on a per-patient basis. Image quality does not affect CNN performance.

TIMI flow and myocardial blushing after rescue PCI and cardiac magnetic resonance: Results from the Myocardial Salvage After Rescue Angioplasty: Evaluation by Magnetic Resonance (SAVE-ME) study

IntroductionThrombolysis is currently reserved for ST-elevation myocardial infarction (STEMI) patients who cannot access timely percutaneous coronary intervention (PCI). In case of failed thrombolysis, rescue PCI is a viable option. Substantial data concerning the outcomes in terms of infarct size and myocardial function after rescue PCI are lacking. MethodsForty patients treated with rescue PCI underwent serial contrast-enhanced cardiac magnetic resonance imaging (CMR) at 1 week, 3 months and 6 months from the index STEMI. Angiographic images were reviewed to assess Thrombolysis in Myocardial Infarction (TIMI) blood flow and TIMI Myocardial Blush Grade (TMBG) in the infarct related artery after PCI. ResultsPatients with lower TMBG at the end of procedure, but not patients with worse TIMI flow, had lower left ventricular ejection fraction (LVEF) and higher volume of late gadolinium enhancement (LGE) on baseline CMR (44 ± 13% vs 52 ± 9%, p = 0.026, and 41 ± 21 ml vs 26 ± 12, p = 0.030, respectively). Patients with lower TMBG remained with significantly lower LVEF at 6 months follow up (48 ± 16% vs 59 ± 14, p = 0.049). ConclusionTMBG after rescue PCI is associated with reduced LVEF and increased LGE burden. As TMBG is a known marker of microvascular damage after STEMI, novel strategies aimed at improving microvascular function in the setting of rescue PCI are needed to improve the outcomes in this patient population.

Usefulness of cardiac magnetic resonance images for prediction of sudden cardiac arrest in patients with mitral valve prolapse: a multicenter retrospective cohort study

BackgroundAn association has been identified between mitral valve prolapse (MVP) and sudden cardiac arrest (SCA), and ventricular arrhythmias (VA). This study aimed to elucidate predictive factors for SCA or VA in MVP patients.MethodsMVP patients who underwent cardiac magnetic resonance (CMR) were retrospectively included. Patients with other structural heart disease or causes of aborted SCA were excluded. Clinical characteristics (sex, age, body mass index, histories of diabetes, hypertension, and dyslipidemia) and electrocardiographic (PR interval, QRS duration, corrected QT interval, inverted T wave in the inferior leads, bundle branch block, and atrial fibrillation), echocardiographic [mitral regurgitation grade, prolapsing mitral leaflet, and right ventricular systolic pressure (RVSP)], and CMR [left atrial volume index, both ventricular ejection fractions, both ventricular end-diastolic and systolic volume indexes, prolapse distance, mitral annular disjunction, systolic curling motion, presence of late gadolinium enhancement (LGE), LGE volume and proportion] parameters were analyzed.ResultsOf the 85 patients [age, 54.0 (41.0–65.0) years; 46 men], seven experienced SCA or VA. Younger age and wide QRS complex were observed more often in the SCA/VA group than in the no-SCA/VA group. The SCA/VA group exhibited lower RVSP, more systolic curling motion and LGE, greater LGE volume, and higher LGE proportion. The presence of LGE [hazard ratio (HR), 19.8; 95% confidence interval (CI) 2.65–148.15; P = 0.004], LGE volume (HR 1.08; 95% CI 1.02–1.14; P = 0.006) and LGE proportion (HR 1.32; 95% CI 1.08–1.60; P = 0.006) were independently associated with higher risk of SCA or VA in MVP patients together with systolic curling motion in each model.ConclusionsThe presence of systolic curling motion, high LGE volume and proportion, and the presence of LGE on CMR were independent predictive factors for SCA or VA in MVP patients.

Looking for appropriate criterias for SCD prevention: prognostic role of MRI in patients with nonischemic ventricular arrhythmias

Abstract Background Currently left ventricular ejection fraction (LVEF) remains the only indicator for identifying candidates for implantable cardioverter-defibrillator (ICD)therapy for the primary prevention of sudden cardiac death (SCD). However the majority of patients suffering SCD have a preserved LVEF and some of them with poor LVEF do not benefit from ICD therapy. Late gadolinium enhancement (LGE) on cardiac-MRI (CMR) has been proposed as an independent predictor of ventricular arrhythmias. Limited data exist on the role and methods of LGE quantification in patients with a nonischemic ventricular arrhythmias. Purpose The goal of this study is to explore whether theextent of LGE would improve risk stratification in patients with a nonischemic ventricular arrhythmias with an indication for implantable cardioverter-defibrillator (ICD) therapy for the primary or secondary prevention of SCD. Methods Fifty six patients with a nonischemic ventricular arrhythmias underwent LGE-CMR prior to ICD implantation for primary and secondary prevention of SCD. LGE extent was quantified using both the full-width half-maximum (FWHM) andthe standard deviation–based (2-SD) method. The primary endpoint was appropriate ICD discharge for sustained ventricular tachyarrhythmia. Results During a median follow-up of 18 [11,5–26,0] months the primary endpoint occurred in 22 patients. The median percentage of LV myocardium fibrosis assessed by the 2-SD method was 9,8 [6,0–18,8]%, while for the FWHM method it was 5,1 [3,0–10,6]% (p&amp;lt;0,001). Intra-observer and inter-observer variability of the FWHM technique was excellent, intraclass correlation coefficients (ICC) 0,97 (95% CI: 0,92–0,99) for intraobserver variability and 0,95 (95% CI: 0,85–0,98) for interobserver variability. The ICC for the 2-SD method were lower: 0,92 (95% CI: 0,76–0,97) and 0,90 (95% CI: 0,69–0,96), for intra- and interobserver variability, respectively. By Cox univariate regression analysis, past syncope, HR: 3,14; (CI: 1,28–7,73), past sustained VT, HR: 8,24; (CI: 2,43–27,96), the presence of LBBB before implantation cardiac resynchronization therapy defibrillator (CRT-D), HR: 0,22; (CI: 0,05–0,96) as well as extent of LGE, HR: 1,067; per 1% increase in the extent of LGE, (CI: 1,029–1,107) demonstrated the strongest association with the appropriate ICD discharge. In multivariate regression analysis, the history of sustained VT, HR: 9,17; (CI: 2,60–32,38; p=0,001) and the value of the extent of LGE, HR: 1,081; per 1% increase in volume of LGE, (CI: 1,034–1,131; p=0,001) demonstrated an independent association with the appropriate ICD discharge. Conclusions FWHM is the optimal semi-automated quantification method in patients with nonischemic ventricular arrhythmias, demonstrating the highest technical consistency. LGE extent is an independent predictor of adverse outcomes in patients with nonischemic ventricular arrhythmia and may have an important role in risk stratification. Funding Acknowledgement Type of funding sources: None. LGE QuantificationEvent-Free Survival

Obstructive and Nonobstructive Hypertrophic Cardiomyopathy: Differences in Global and Segmental Myocardial Strain by Cardiac Magnetic Resonance Feature Tracking.

To evaluate any significant differences in myocardial strain between hypertrophic obstructive cardiomyopathy (HOCM) and nonobstructive ones (HNCM), as assessed by cardiac magnetic resonance feature tracking (CMR-FT). A total of 17 patients (mean age: 54±14 y) with echocardiographic diagnosis of HOCM (left ventricular outflow tract obstruction peak gradient ≥30 mm Hg), 19 patients (mean age: 49±16 y) with HNCM (peak gradient <30 mm Hg), and 18 age-matched and gender-matched healthy controls (mean age: 42±14 y). All patients underwent cardiac MRI with SSFP-cine to assess left ventricular global and segmental strain analysis by CMR-FT. Late gadolinium enhancement (LGE) sequences were used for semiautomatic quantification of LGE volume, mass, and percentage. The magnitude of global radial, circumferential, and longitudinal strain as well as strain rate were significantly lower in all patients in comparison to controls (P<0.001), except for radial and circumferential strain between HOCM and controls (P=0.270; P=0.154). The latter strain parameters were significantly higher in HOCM than HNCM (radial strain: 31.67±7.55 vs. 21.26±7.10, P<0.001; circumferential strain: -17.94±2.78 vs. -13.46±3.42, P<0.001). Radial and circumferential strain and circumferential diastolic strain rate were higher in mid-anterior (P<0.001), mid-anteroseptal (P<0.001), and all apical segments (P<0.005) between the 2 groups of patients. Moreover, longitudinal strain was higher only in apical segments in HOCM (P<0.02). HOCM patients showed higher left ventricular apical, mid-anterior, and mid-anteroseptal strain parameters compared with HNCM. These differences were independent of corresponding segmental thickness and LGE amount.

B-IN02-03 USING PULSED ELECTRIC FIELDS TO CAUSE FOCAL FIBROSIS IN THE INTERVENTRICULAR SEPTUM

Pulse electric fields (PEF) are being investigated as an alternative ablation modality to traditional radiofrequency ablation for modification of myocardial substrate. Assess the extent and time course of myocardial scar formation caused by application of PEF at the interventricular septum. Four-week survival experiments were performed in 8 canines. Energy was delivered using ablation catheters in bipolar configuration to apply PEF to the septum. Two animals were administered pulses at microsecond pulse widths and six received nanosecond pulses for a total 75-189 J delivered per animal. MRI studies were performed in 4 of the 8 animals. Scar formation was assessed by measuring late gadolinium enhancement (LGE) and confirmed by histology. Sites of PEF delivery exhibited myocardial edema on triple inversion recovery and early scar with some LGE visible after 7 days. Lesion volumes were larger for transmural configurations vs. bipolar PEF delivered in a single cardiac chamber (10.7 ± 2.3 cm3 vs. 2.9 ± 1.1 cm3). At 30 days, lesions predominantly exhibited LGE and total lesion volumes were similar for both groups (5.3 ± 2.4 cm3 vs. 4.0 ± 0.2 cm3). Transmural MRI lesions were achieved when bipolar electrodes were placed on either side of the septum, and total lesion volume was dose-dependent. Myocardial fibrosis was identified on histology. Bipolar configurations entirely within a chamber produced superficial lesions, even with delivery of higher energy. Application of PEF to the myocardium can cause substrate modification, including transmural fibrosis. Lesion volume is dose-dependent for transmural electrode configurations.

Prognostic Significance of Nonischemic Myocardial Fibrosis in Patients With Normal LV Volumes and Ejection-Fraction

ObjectivesThis study aims to investigate the prognostic significance of late gadolinium enhancement (LGE) in patients without coronary artery disease and with normal range left ventricular (LV) volumes and ejection fraction. BackgroundNonischemic patterns of LGE with normal LV volumes and ejection fraction are increasingly detected on cardiovascular magnetic resonance, but their prognostic significance, and consequently management, is uncertain. MethodsPatients with midwall/subepicardial LGE and normal LV volumes, wall thickness, and ejection fraction on cardiovascular magnetic resonance were enrolled and compared to a control group without LGE. The primary outcome was actual or aborted sudden cardiac death (SCD). ResultsOf 748 patients enrolled, 401 had LGE and 347 did not. The median age was 50 years (interquartile range: 38-61 years), LV ejection fraction 66% (interquartile range: 62%-70%), and 287 (38%) were women. Scan indications included chest pain (40%), palpitation (33%) and breathlessness (13%). No patient experienced SCD and only 1 LGE+ patient (0.13%) had an aborted SCD in the 11th follow-up year. Over a median of 4.3 years, 30 patients (4.0%) died. All-cause mortality was similar for LGE+/- patients (3.7% vs 4.3%; P = 0.71) and was associated with age (HR: 2.04 per 10 years; 95% CI: 1.46-2.79; P < 0.001). Twenty-one LGE+ and 4 LGE- patients had an unplanned cardiovascular hospital admission (HR: 7.22; 95% CI: 4.26-21.17; P < 0.0001). ConclusionsThere was a low SCD risk during long-term follow-up in patients with LGE but otherwise normal LV volumes and ejection fraction. Mortality was driven by age and not LGE presence, location, or extent, although the latter was associated with greater cardiovascular hospitalization for suspected myocarditis and symptomatic ventricular tachycardia.

Pulsed field ablation prevents chronic atrial fibrotic changes and restrictive mechanics after catheter ablation for atrial fibrillation.

AimsPulsed field ablation (PFA), a non-thermal ablative modality, may show different effects on the myocardial tissue compared to thermal ablation. Thus, this study aimed to compare the left atrial (LA) structural and mechanical characteristics after PFA vs. thermal ablation.Methods and resultsCardiac magnetic resonance was performed pre-ablation, acutely (<3 h), and 3 months post-ablation in 41 patients with paroxysmal atrial fibrillation (AF) undergoing pulmonary vein (PV) isolation with PFA (n = 18) or thermal ablation (n = 23, 16 radiofrequency ablations, 7 cryoablations). Late gadolinium enhancement (LGE), T2-weighted, and cine images were analysed. In the acute stage, LGE volume was 60% larger after PFA vs. thermal ablation (P < 0.001), and oedema on T2 imaging was 20% smaller (P = 0.002). Tissue changes were more homogeneous after PFA than after thermal ablation, with no sign of microvascular damage or intramural haemorrhage. In the chronic stage, the majority of acute LGE had disappeared after PFA, whereas most LGE persisted after thermal ablation. The maximum strain on PV antra, the LA expansion index, and LA active emptying fraction declined acutely after both PFA and thermal ablation but recovered at the chronic stage only with PFA.ConclusionPulsed field ablation induces large acute LGE without microvascular damage or intramural haemorrhage. Most LGE lesions disappear in the chronic stage, suggesting a specific reparative process involving less chronic fibrosis. This process may contribute to a preserved tissue compliance and LA reservoir and booster pump functions.

Prognostic importance of acute phase extracellular volume evaluated by cardiac magnetic resonance imaging for patients with acute myocardial infarction.

Myocardial extracellular volume (ECV) by cardiac magnetic resonance (CMR) in the acute phase of acute myocardial infarction (MI) more precisely predicts the functional recovery of infarct-related wall motion abnormalities and left ventricular (LV) remodeling than late gadolinium enhancement (LGE). The purpose of this study was to evaluate the prognostic importance of acute phase ECV in patients with AMI. We evaluated 61 consecutive AMI patients using 3.0T CMR. CMR examination was performed median 10days (7-15days) after PCI. Primary endpoint was defined as major adverse cardiac event (MACE). The median follow-up duration was 3.1years, and MACE occurred in 11 (18%) patients. Although LVEF and % infarct LGE volume were not associated with MACE in this study population, higher infarct ECV predicted the MACE with a hazard ratio (HR) of 4.04 (P = 0.02). High global ECV, which was a combined assessment of infarct ECV and remote ECV, also predicted MACE with a HR of 5.24 (P = 0.035). The addition of infarct ECV to remote ECV (global chi-squared score: 1.4) resulted in a significantly increased global chi-squared score (6.7; P = 0.017). Furthermore, after adjusting for the calculated propensity score for high global ECV, it remained an independent predictor of MACE with HR of 5.10 (P = 0.04). The quantification of ECV in the acute phase among AMI patients may provide an incremental prognostic value for predicting MACE beyond that of clinical, angiographic, and functional variables.

3D whole-heart grey-blood late gadolinium enhancement cardiovascular magnetic resonance imaging

PurposeTo develop a free-breathing whole-heart isotropic-resolution 3D late gadolinium enhancement (LGE) sequence with Dixon-encoding, which provides co-registered 3D grey-blood phase-sensitive inversion-recovery (PSIR) and complementary 3D fat volumes in a single scan of < 7 min.MethodsA free-breathing 3D PSIR LGE sequence with dual-echo Dixon readout with a variable density Cartesian trajectory with acceleration factor of 3 is proposed. Image navigators are acquired to correct both inversion recovery (IR)-prepared and reference volumes for 2D translational respiratory motion, enabling motion compensated PSIR reconstruction with 100% respiratory scan efficiency. An intermediate PSIR reconstruction is performed between the in-phase echoes to estimate the signal polarity which is subsequently applied to the IR-prepared water volume to generate a water grey-blood PSIR image. The IR-prepared water volume is obtained using a water/fat separation algorithm from the corresponding dual-echo readout. The complementary fat-volume is obtained after water/fat separation of the reference volume. Ten patients (6 with myocardial scar) were scanned with the proposed water/fat grey-blood 3D PSIR LGE sequence at 1.5 T and compared to breath-held grey-blood 2D LGE sequence in terms of contrast ratio (CR), contrast-to-noise ratio (CNR), scar depiction, scar transmurality, scar mass and image quality.ResultsComparable CRs (p = 0.98, 0.40 and 0.83) and CNRs (p = 0.29, 0.40 and 0.26) for blood-myocardium, scar-myocardium and scar-blood respectively were obtained with the proposed free-breathing 3D water/fat LGE and 2D clinical LGE scan. Excellent agreement for scar detection, scar transmurality, scar mass (bias = 0.29%) and image quality scores (from 1: non-diagnostic to 4: excellent) of 3.8 ± 0.42 and 3.6 ± 0.69 (p > 0.99) were obtained with the 2D and 3D PSIR LGE approaches with comparable total acquisition time (p = 0.29). Similar agreement in intra and inter-observer variability were obtained for the 2D and 3D acquisition respectively.ConclusionThe proposed approach enabled the acquisition of free-breathing motion-compensated isotropic-resolution 3D grey-blood PSIR LGE and fat volumes. The proposed approach showed good agreement with conventional 2D LGE in terms of CR, scar depiction and scan time, while enabling free-breathing acquisition, whole-heart coverage, reformatting in arbitrary views and visualization of both water and fat information.

Prognostic value of cardiac magnetic resonance septal late gadolinium enhancement patterns for periaortic ventricular tachycardia ablation: Heterogeneity of the anteroseptal substrate in nonischemic cardiomyopathy

Ventricular tachycardia (VT) from the anteroseptal subtype of nonischemic cardiomyopathy has a high probability of recurrence after catheter ablation. The purpose of this study was to determine the predictive value of septal scar patterns by late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) on ablation outcomes in patients with VT arising from an anteroseptal substrate. Patients with periaortic VT arising from an anteroseptal substrate with preprocedural wideband LGE-CMR were divided into 2 groups by the degree of longitudinal septal LGE extension as full-length septal (≥80% anteroposterior length) or partial septal (<80% anteroposterior length). Septal LGE volumes were quantified in those with and without VT recurrence. Among 234 patients referred for scar-related VT ablation between 2017 and 2020, 25 patients (92% male; age 64 ± 8 years) and a total of 108 VTs were analyzed. A greater number of VT morphologies were induced in patients with full-length septal LGE compared to partial septal LGE (median [interquartile range]: 5 [3-9] vs 2 [1-4]; P = .005). Patients with VT recurrence had larger septal LGE volumes compared to those without recurrence (11.4 mL [8.8-13.9] vs 4.2 mL [0-9.5]; P = .012). At median follow-up of 16 months (5-22), overall freedom from VT recurrence was 52% and significantly higher in patients with partial septal LGE than in those with full-length septal LGE (80% vs 20%; P = .005). VT originating from an anteroseptal substrate is associated with heterogeneous patterns and extent of CMR septal scar. Preprocedural imaging may substratify this challenging patient population for the propensity for multiple induced VT morphologies and recurrence after catheter ablation.

Abstract 17108: Natural History of Cardiomyopathy and Cardiac Stress Response in Young Dogs With Golden Retriever Muscular Dystrophy

Introduction: Duchenne muscular dystrophy (DMD) and the genetically homologous model, golden retriever muscular dystrophy (GRMD), are x-linked conditions that cause progressive muscle wasting and cardiomyopathy. We previously defined a late onset DMD-like dilated cardiomyopathy in adult GRMD dogs and aimed to extend that work to young dogs used for preclinical studies. The goal of this study was to characterize the early natural history and cardiac stress response of GRMD cardiomyopathy. Methods: A prospective imaging study was completed in 10 GRMD dogs and 8 age-matched normal littermates at 3, 6, and 12 months of age. Electrocardiography (ECG), echocardiography with speckle tracking, and cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) and myocardial T1 mapping were assessed. In an effort to identify early subclinical evidence of cardiomyopathy, we conducted a dobutamine stress test in an additional subset of dogs (17 GRMD vs. 6 normal). Fractional shortening (FS) was assessed using echocardiography during dobutamine infusion (5-25 μg/kg/min) at 2 months of age, with follow up studies (4 GRMD vs. 6 normal) at 4.5 and 6 months. Results: Heart rate and ECG Q/R ratios (lead II, III, and aVF) were greater in GRMD dogs at 12 months (p&lt;0.04 for all), and PR interval was shortened at 6 months (p=0.02). No systolic functional differences were seen between GRMD and normal dogs using echocardiography. No differences in circumferential strain were seen. CMR left ventricular end-diastolic volume, end-systolic volume, and myocardial mass were smaller in GRMD dogs from 6 months onward (p=0.014, 0.008, and 0.0013). LGE and extracellular volume calculated from T1 mapping did not differ on CMR. A diminished inotropic response, shown by a lower increase of FS (ΔFS), was seen in GRMD dogs during the dobutamine stress test (beginning at a dose of 5 μg/kg/min, 13.9±4.8% vs. 21.8±3.0%, p=0.003) at 2 months of age but not at 4.5 and 6 months. Conclusions: We demonstrated ECG changes and heart size differences in GRMD dogs as early as 6-12 months of age. While cardiac function was preserved, the inotropic response to dobutamine stress was blunted in 2-month-old GRMD dogs, potentially providing an early subclinical marker for DMD therapeutic research.

Structural and functional reverse myocardial remodeling following transcatheter aortic valve replacement

Abstract Background Myocardial reverse remodeling determines outcome in patients with severe aortic stenosis (AS) following transcatheter aortic valve replacement (TAVR). However, little is known about the interplay of myocardial function and structure after TAVR. Since cardiac magnetic resonance (CMR) imaging allows comprehensive quantification of both structure and function we aimed to assess changes in myocardial tissue composition and deformation before and following TAVR. Methods CMR imaging was performed in 40 prospectively enrolled patients with severe AS before and one year after TAVR. Myocardial function was characterized using volumetry and CMR-feature-tracking (FT) deformation imaging of left ventricular (LV) global longitudinal strain (GLS) and atrial function (atrial reservoir ES, conduit Ee and booster pump strain EA). Myocardial structure was assessed using T1 mapping and late gadolinium enhancement (LGE) analysis. LV cellular and matrix volumes were calculated based on extra cellular volume fraction (ECV) and LV mass. CMR-FT results were compared to a control group of twenty patients with normal biventricular function. Moreover, biomarkers (NT-proBNP), functional (six-minute-walking-test) and clinical status (NYHA, Minnesota LIVING WITH HEART FAILURE score) were determined at baseline and one-year follow-up. Results Regression of both cellular (−20.6%, p&amp;lt;0.001) and matrix volumes (−12.3%, p=0.003) and subsequently increased ECV (+9.0%, p=0.001) were documented one year after TAVR. Ventricular and atrial strains were impaired at baseline (GLS p=0.004, Es p&amp;lt;0.001, Ee p&amp;lt;0.001) and recovered during follow-up (GLS p&amp;lt;0.001, Es p=0.005, Ee p=0.001). These changes were paralleled by improvements in NYHA (p&amp;lt;0.001) and Minnesota (p&amp;lt;0.001) scores as well as decline in NT-proBNP levels (p=0.001). There was a significant association of LV fibrosis as defined by matrix volume and extent of LGE and ventricular and atrial functional impairment (correlation of matrix volume and: GLS r=0.57, p&amp;lt;0.001, Es r=−0.44, p=0.009; correlation of LGE%LV and: GLS r=0.41, p=0.015, Es: r=−0.4, p=0.02, and Ea: r=−0.41, p=0.02). Conclusion Regression of fibrosis and cellular hypertrophy determine improved myocardial function and recovery from heart failure following TAVR. Prognostic implications of the observed changes will need to be explored next to identify makers and therapeutic targets for optimized management of these patients. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): German Research Foundation (DFG, CRC 1002, D1)