Late Gadolinium Enhancement Magnetic Resonance Research Articles

Antiarrhythmic and Anti-Inflammatory Effects of Sacubitril/Valsartan on Post-Myocardial Infarction Scar.

Sacubitril/valsartan (Sac/Val) is superior to angiotensin-converting enzyme inhibitors in reducing the risk of heart failure hospitalization and cardiovascular death, but its mechanistic data on myocardial scar after myocardial infarction (MI) are lacking. The objective of this work was to assess the effects of Sac/Val on inflammation, fibrosis, electrophysiological properties, and ventricular tachycardia inducibility in post-MI scar remodeling in swine. After MI, 22 pigs were randomized to receive β-blocker (BB; control, n=8) or BB+Sac/Val (Sac/Val, n=9). The systemic immune response was monitored. Cardiac magnetic resonance data were acquired at 2-day and 29-day post MI to assess ventricular remodeling. Programmed electrical stimulation and high-density mapping were performed at 30-day post MI to assess ventricular tachycardia inducibility. Myocardial samples were collected for histological analysis. Compared with BB, BB+Sac/Val reduced acute circulating leukocytes (P=0.009) and interleukin-12 levels (P=0.024) at 2-day post MI, decreased C-C chemokine receptor type 2 expression in monocytes (P=0.047) at 15-day post MI, and reduced scar mass (P=0.046) and border zone mass (P=0.043). It also lowered the number and mass of border zone corridors (P=0.020 and P=0.05, respectively), scar collagen I content (P=0.049), and collagen I/III ratio (P=0.040). Sac/Val reduced ventricular tachycardia inducibility (P=0.026) and the number of deceleration zones (P=0.016). After MI, compared with BB, BB+Sac/Val was associated with reduced acute systemic inflammatory markers, reduced total scar and border zone mass on late gadolinium-enhanced magnetic resonance imaging, and lower ventricular tachycardia inducibility.

RAS Dataset: A 3D Cardiac LGE-MRI Dataset for Segmentation of Right Atrial Cavity

The current challenge in effectively treating atrial fibrillation (AF) stems from a limited understanding of the intricate structure of the human atria. The objective and quantitative interpretation of the right atrium (RA) in late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) scans relies heavily on its precise segmentation. Leveraging the potential of artificial intelligence (AI) for RA segmentation presents a promising solution. However, the successful implementation of AI in this context necessitates access to a substantial volume of annotated LGE-MRI images for model training. In this paper, we present a comprehensive 3D cardiac dataset comprising 50 high-resolution LGE-MRI scans, each meticulously annotated at the pixel level. The annotation process underwent rigorous standardization through crowdsourcing among a panel of medical experts, ensuring the accuracy and consistency of the annotations. Our dataset represents a significant contribution to the field, providing a valuable resource for advancing RA segmentation methods.

Regional conduction velocities determined by noninvasive mapping are associated with arrhythmia-free survival after atrial fibrillation ablation

BackgroundAtrial arrhythmogenic substrate is a key determinant of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI), and reduced conduction velocities have been linked to adverse outcome. However, a noninvasive method to assess such electrophysiologic substrate is not available to date. ObjectiveThis study aimed to noninvasively assess regional conduction velocities and their association with arrhythmia-free survival after PVI. MethodsA consecutive 52 patients scheduled for AF ablation (PVI only) and 19 healthy controls were prospectively included and received electrocardiographic imaging (ECGi) to noninvasively determine regional atrial conduction velocities in sinus rhythm. A novel ECGi technology obviating the need of additional computed tomography or cardiac magnetic resonance imaging was applied and validated by invasive mapping. ResultsMean ECGi-determined atrial conduction velocities were significantly lower in AF patients than in healthy controls (1.45 ± 0.15 m/s vs 1.64 ± 0.15 m/s; P < .0001). Differences were particularly pronounced in a regional analysis considering only the segment with the lowest average conduction velocity in each patient (0.8 ± 0.22 m/s vs 1.08 ± 0.26 m/s; P < .0001). This average conduction velocity of the “slowest” segment was independently associated with arrhythmia recurrence and better discriminated between PVI responders and nonresponders than previously proposed predictors, including left atrial size and late gadolinium enhancement (magnetic resonance imaging). Patients without slow-conduction areas (mean conduction velocity <0.78 m/s) showed significantly higher 12-month arrhythmia-free survival than those with 1 or more slow-conduction areas (88.9% vs 48.0%; P = .002). ConclusionThis is the first study to investigate regional atrial conduction velocities noninvasively. The absence of ECGi-determined slow-conduction areas well discriminates PVI responders from nonresponders. Such noninvasive assessment of electrical arrhythmogenic substrate may guide treatment strategies and be a step toward personalized AF therapy.

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.

Hybrid Magnetic Resonance Positron Emission Tomography Is Associated With Cardiac-Related Outcomes in Cardiac Sarcoidosis

BackgroundImaging with late gadolinium enhancement (LGE) magnetic resonance (MR) and 18F-fluorodeoxyglucose (18F-FDG) PET allows complementary assessment of myocardial injury and disease activity and has shown promise for improved characterization of active cardiac sarcoidosis (CS) based on the combined positive imaging outcome, MR(+)PET(+). ObjectivesThis study aims to evaluate qualitative and quantitative assessments of hybrid MR/PET imaging in CS and to evaluate its association with cardiac-related outcomes. MethodsA total of 148 patients with suspected CS underwent hybrid MR/PET imaging. Patients were classified based on the presence/absence of LGE (MR+/MR−), presence/absence of 18F-FDG (PET+/PET−), and pattern of 18F-FDG uptake (focal/diffuse) into the following categories: MR(+)PET(+)FOCAL, MR(+)PET(+)DIFFUSE, MR(+)PET(−), MR(−)PET(+)FOCAL, MR(−)PET(+)DIFFUSE, MR(−)PET(−). Further analysis classified MR positivity based on %LGE exceeding 5.7% as MR(+/−)5.7%. Quantitative values of standard uptake value, target-to-background ratio, target-to-normal-myocardium ratio (TNMRmax), and T2 were measured. The primary clinical endpoint was met by the occurrence of cardiac arrest, ventricular tachycardia, or secondary prevention implantable cardioverter-defibrillator (ICD) before the end of the study. The secondary endpoint was met by any of the primary endpoint criteria plus heart failure or heart block. MR/PET imaging results were compared between those meeting or not meeting the clinical endpoints. ResultsPatients designated MR(+)5.7%PET(+)FOCAL had increased odds of meeting the primary clinical endpoint compared to those with all other imaging classifications (unadjusted OR: 9.2 [95% CI: 3.0-28.7]; P = 0.0001), which was higher than the odds based on MR or PET alone. TNMRmax achieved an area under the receiver-operating characteristic curve of 0.90 for separating MR(+)PET(+)FOCAL from non-MR(+)PET(+)FOCAL, and 0.77 for separating those reaching the clinical endpoint from those not reaching the clinical endpoint. ConclusionsHybrid MR/PET image–based classification of CS was statistically associated with clinical outcomes in CS. TNMRmax had modest sensitivity and specificity for quantifying the imaging-based classification MR(+)PET(+)FOCAL and was associated with outcomes. Use of combined MR and PET image–based classification may have use in prognostication and treatment management in CS.

Expression of Circulating miR-21 and -29 and their Association with Myocardial Fibrosis in Hypertrophic Cardiomyopathy.

Hypertrophic Cardiomyopathy (HCM) is characterized by myocardial hypertrophy, fibrosis, and sarcomeric disarray. To evaluate the expression levels of circulating miR-21 and -29 in patients with HCM and their association with clinical characteristics and myocardial fibrosis. In this case-control study, 27 subjects with HCM, 13 subjects with hypertensive cardiomyopathy, and 10 control subjects were enrolled. Evaluation of patients' functional capacity was made by the six-minute walk test. Echocardiographic measurements of left ventricle systolic and diastolic function were conducted. Cardiac magnetic resonance late gadolinium enhancement (LGE) -through a semiquantitative evaluation- was used in the assessment of myocardial fibrosis extent in HCM patients. The expression of miR-21 and -29 in peripheral blood samples of all patients was measured via the method of quantitative reverse transcription polymerase chain reaction. Circulating levels of miR-21 were higher in both hypertensive and HCM (p<0.001) compared to controls, while expression of miR-29 did not differ between the three studied groups. In patients with HCM and LGE-detected myocardial fibrosis in more than 4 out of 17 myocardial segments, delta CT miR-21 values were lower than in patients with myocardial LGE in 3 or fewer myocardial segments (2.71 ± 1.06 deltaCT vs. 3.50 ± 0.55 deltaCT, p=0.04), indicating the higher expression of circulating miR-21 in patients with more extensive myocardial fibrosis. MiR-21 was overexpressed in patients with HCM and hypertensive cardiomyopathy. Importantly, in patients with HCM, more extensive myocardial fibrosis was associated with higher levels of miR-21.

Association between left bundle branch block and ventricular septal mid-wall fibrosis in patients with preserved left ventricular ejection fraction

BackgroundThe left bundle branch block (LBBB) is associated with ventricular septal mid-wall fibrosis (SMF) in patients with dilated cardiomyopathy (DCM). However, whether LBBB is also associated with SMF in patients with preserved left ventricular ejection fraction (LVEF) remains unclear. MethodsWe performed a retrospective study of 210 patients with preserved LVEF (male, n = 116; female, n = 94; mean age, 44 ± 17 years). LBBB was defined as QRS duration ≥140 ms for men or ≥ 130 ms for women, QS or rS in V1-V2, mid-QRS notching or slurring in at least two leads (V1, V2, V5, V6, I, and aVL). SMF determined by late gadolinium-enhancement cardiovascular magnetic resonance was defined as stripe-like or patchy mid-myocardial hyper-enhancement in the interventricular septal segments. ResultsSMF was detected in 24.8% (52/210) of these patients. The proportion of patients with SMF with LBBB was higher than the proportion of patients with SMF without LBBB (58.3% vs. 20.4%; P < 0.001). In the forward multivariate logistic analysis, LBBB (OR, 4.399; 95% CI, 1.774–10.904; P = 0.001) and age (OR, 1.028; 95% CI, 1.006–1.051; P = 0.011) were independently associated with SMF. The presence of LBBB showed a sensitivity of 27%%, specificity of 94%, positive predictive value of 58%%, and negative predictive value of 80% for the detection of SMF. ConclusionLBBB was significantly associated with SMF in hospitalized patients with preserved LVEF. Screening with a resting 12‑lead ECG may help to identify patients who are at a high risk of the presence of SMF.

FK-means: automatic atrial fibrosis segmentation using fractal-guided K-means clustering with Voronoi-clipping feature extraction of anatomical structures.

Assessment of left atrial (LA) fibrosis from late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) adds to the management of patients with atrial fibrillation. However, accurate assessment of fibrosis in the LA wall remains challenging. Excluding anatomical structures in the LA proximity using clipping techniques can reduce misclassification of LA fibrosis. A novel FK-means approach for combined automatic clipping and automatic fibrosis segmentation was developed. This approach combines a feature-based Voronoi diagram with a hierarchical 3D K-means fractal-based method. The proposed automatic Voronoi clipping method was applied on LGE-MRI data and achieved a Dice score of 0.75, similar to the score obtained by a deep learning method (3D UNet) for clipping (0.74). The automatic fibrosis segmentation method, which uses the Voronoi clipping method, achieved a Dice score of 0.76. This outperformed a 3D UNet method for clipping and fibrosis classification, which had a Dice score of 0.69. Moreover, the proposed automatic fibrosis segmentation method achieved a Dice score of 0.90, using manual clipping of anatomical structures. The findings suggest that the automatic FK-means analysis approach enables reliable LA fibrosis segmentation and that clipping of anatomical structures in the atrial proximity can add to the assessment of atrial fibrosis.

Association Between Left Ventricular Scar and Ventricular Ectopy in People Living With and Without HIV

BackgroundPeople living with HIV (PLWH) have greater risk for arrhythmic sudden death and heart failure than people without HIV (PWOH), though risk identifiers remain understudied. Higher ventricular ectopy (VE) burden reflects increased arrhythmic susceptibility and cardiomyopathy risk. ObjectivesThe purpose of this study was to test if myocardial scar measured by late gadolinium-enhancement cardiovascular magnetic resonance (LGE-CMR) associates with VE by ambulatory electrocardiographic monitoring among PLWH and PWOH with risk factors for HIV, and if the association differs by HIV. MethodsParticipants from 3 cohorts of PLWH and PWOH underwent electrocardiographic monitoring (median wear time 8.3 days) and CMR. Using multivariable regression, we assessed: 1) associations between scar metrics and VE, adjusting for demographics, HIV serostatus, substance use, cardiovascular risk factors, and left ventricular (LV) function/structure; and 2) effect measure modification by HIV. ResultsOf 329 participants (median age 55 years, 30% women, 62% PLWH), 109 had LGE (62% PLWH). Ischemic or major nonischemic pattern LGE was associated with high VE burden (adjusted OR: 2.32, P = 0.004) and more PVCs/day (141% higher, P < 0.001). Among people with LGE, greater scar mass correlated with more PVCs/day (P = 0.028). Associations persisted after adjustment for LV function/structure and when excluding PLWH with HIV viremia and showed no effect measure modification by HIV. ConclusionsIschemic or major nonischemic pattern LGE and greater scar mass correlated with higher VE burden, independently of LV structure/function, HIV serostatus, and HIV viremia. The findings highlight specific scar characteristics common to PLWH and PWOH with risk factors for HIV that may portend higher risk for arrhythmias and heart failure.

Myocardial fibrosis activity following ST-segment elevation myocardial infarction

Abstract Background Myocardial fibrosis following myocardial infarction (MI) is a key healing mechanism and involves widespread fibroblast activation. Once activated, fibroblasts express fibroblast activation protein (FAP) (1). Hybrid positron emission tomography (PET) imaging of radiolabelled fibroblast activation protein inhibitor (FAPI) fused with cardiovascular magnetic resonance (68Ga-FAPI PET/MR) is an emerging method for assessing myocardial fibrosis activity that may provide additional insights into the recovery of the heart following MI. Methods Forty patients with acute (&amp;lt;4 weeks), 19 with recent (12 weeks), and 19 with prior established ST-segment elevation MI (&amp;gt;12 months), and 20 healthy volunteer participants underwent 68Ga-FAPI PET/MR. Participants were imaged 30 min after administration of 100-200 MBq 68Ga-FAPI-04. Image analysis was performed using FusionQuant (Cedars Sinai, Los Angeles, California). 68Ga-FAPI uptake was quantified by maximum standardised uptake value (SUVmax) and tissue-to-background ratio (TBRmax) correcting for blood-pool activity in the left ventricle. Comparisons between were assessed with one-way ANOVA with Tukey-Kramer post-hoc testing where significant differences were detected. A 2-sided p-value of &amp;lt;0.05 denoted statistical significance. Results Participants were predominantly middle-aged men with similar sized infarcts (peak plasma cardiac troponin concentrations and post-MI left ventricular ejection fraction) (Table). Blood pool tracer activity was also similar between groups. Focal myocardial 68Ga-FAPI uptake localised to areas of the infarct and peri-infarct zones on magnetic resonance late gadolinium enhancement imaging (Figure). Both myocardial SUVmax and TBRmax varied between infarcts of different ages, being highest in acute (TBRmax 4.1±1.2) and lowest in those with prior established MI (2.1±0.7, Table and Figure). Conclusions Fibrosis activity is greatest in the immediate aftermath of acute MI with a step-wise reduction in the weeks and years that follow. Fibrosis activity continues for many months and years after acute infarction.FigureTable

The benefit of a double ventricular extra stimuli protocol to improve functional substrate mapping during ablation of ventricular tachycardia. - The S3-VT-FREE project

Abstract Introduction Ablation of ventricular tachycardia (VT) based on substrate-based mapping has been proposed to itemize areas of interest identifying areas of low-voltage, late potentials (LPs), and deceleration zones (DZs). However, partial delineation of targets for ablation is likely responsible for a suboptimal long-term success rate. The abnormal electrograms (EGMs), featuring low-voltage near-field components may be hidden within the high-amplitude far-field signal. We hypothesized that the acquisition of functional mapping after double ventricular extrastimuli (S3 protocol) would uncover relevant areas of functional substrate that could be missed during sinus or S1 map. We aim to evaluate the potential benefit and the feasibility of functional substrate mapping using an S3 protocol for VT ablation and to assess its colocalization with detected corridors using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). Methods We included consecutively 29 patients with structural cardiomypathy who underwent a VT ablation. The S3 protocol included: (1) assessment of the ventricular effective refractory period (ERP), (2) pacing protocol from the apex of the right ventricle with S1 x 6 (cycle length: 600ms) followed by S2 (ERP+30ms) and S3 (ERP+50ms). Electroanatomical mapping was acquired with the EnsiteX system (Abbott, IL) using HD Grid catheter and omnipolar signals. ILAMs were used to identify deceleration zones and areas of late potentials were identified for all maps. A non-invasive substrate assessment was done with LGE-MRI and post-processing with a commercially available system (ADAS3D, Spain) with automated identification of corridors. Results The S3 protocol was completed in 25 of the 29 procedures (86.2%). The repeated induction of ventricular arrhythmias did not allow for full protocol of the S3 protocol in 4 patients (13.8%). The functional substrate identified during the S3 activation mapping was significantly more extensive than the one identified using S1 and S2 activation mappings (p&amp;lt;0.05) (Table). The S3 protocol unmasked a higher number of DZs (p&amp;lt;0.01), a wider area of LPs (p&amp;lt;0.01), and a longer duration of the DZs (p=0.01). All DZ maps were compared with preprocedural cardiac magnetic resonance. The number of DZs matching with conduction corridors identified by LGE-MRI was higher in the activation mapping of S3 compared with the S1 and S2 ones (p=0.02). After VT ablation based on an S3 protocol, 88% of patients have been VT free during a median follow-up of 9 months. Conclusions This novel substrate-based protocol to assess the ventricular functional substrate is feasible in the majority of patients (86.2%) and allows for a better identification of targets for ablation and could facilitate VT ablation, and improve the prognosis of the patients after ablation.

A pilot randomized controlled trial of novel reperfusion method in patients of acute st elevation myocardial infarction during primary percutaneous coronary intervention

Abstract Objectives This study was conducted to explore the feasibility, clinical safety and potential effects of a novel reperfusion method, Volume-Controlled Reperfusion (VCR) in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Background Reperfusion injury is associated with larger infarct size (IS) and drawback of long-term overcome. Microvascular obstruction (MVO) as detected on late gadolinium-enhanced cardiovascular magnetic resonance (LGE-CMR) is the most used index for assessment of reperfusion injury. To date, there is no feasible gradual reperfusion method in primary PCI setting. VCR is an original reperfusion method feasible in primary PCI for both accurate gradual reperfusion and intermittent flow. Methods A total of 60 patients with STEMI presenting within 12 h of symptom onset undergoing PPCI were randomized enrolled, 30 patients in VCR group and 30 patients in control group with routine PCI only. VCR was performed with the dual catheter technique, 10ml of artery blood diluted with10ml of heparin saline infused via manual aspiration catheter at speed of 20ml/min for 10 rounds after suspending the antegrade flow using a prophylactic inflated balloon. Then, routine PCI procedure as usual. The primary endpoint was major adverse cardiac events (MACE) during hospitalization, the main second endpoint was the MVO extent difference measured on day 5-7 post-procedure. Results Baseline characteristics were well matched between two groups. No major adverse cardiac events (MACE) found in-hospital or 30 days followed up. There were no complications associated with VCR procedure. 43 patients had LGE-CMR exam (22 in Control group, 21 in VCR group, among them, 14/22 were anterior wall control and 14/21 VCR). There was no significant difference in infarct size, MVO or CMR-LVEF in total patients between VCR and control. However, significant difference in CMR-LVEF was noted between control and VCR anterior wall subgroup (40.53 ± 7.39 vs50.55 ± 7.55; P=0.002), the average of MVO and MVO of infarct size were smaller in VCR group while no significant difference. Conclusions This is the pilot RCT study showed VCR method was feasibility and clinical safe among patients with acute STEMI during PPCI and 30 days followed up, indicated potential attenuate effect in reperfusion injury as well. Staged II study is needed to verify clinical benefit.VCR illustrationLGE-CMR figure

Abstract 12357: Investigating Sex-Specific Factors Influencing Atrial Fibrillation Burden in Patients With Persistent Atrial Fibrillation: A DECAAF II Subanalysis

Background: Atrial Fibrillation(AF) burden provides insights beyond the common binary classification of AF recurrence after catheter ablation(CA). Objective: We sought to investigate the predictors of AF burden in patients with persistent AF(PeAF) at 1 year post-CA, with a focus on sex-based differences. The analysis was conducted separately for both female and male. Methods: We examined all PeAF patients in the DECAAF II trial and divided them into 2 groups, women and men. Baseline demographics and late gadolinium enhancement magnetic resonance imaging data were reviewed. Patients were instructed to provide single-lead home ECG strips once daily. AF burden was calculated by dividing the total number of days in AF over the total number of days when strips were sent. Univariate and multivariate analysis were performed to predict AF burden beyond the 3-month blanking period. Results: We included 658 patients(20% Female,80% male) who transmitted 215825 ECG strips. The average AF burden across the population was 17%. The mean AF burden was higher in women(21%) than in men(16%)(p&lt;0.01). In women, on univariate analysis, baseline fibrosis(p&lt;0.05), history of stroke(p&lt;0.01) and left atrial(LA) volume(p&lt;0.01) were positively correlated with AF burden. After conducting a multivariate analysis, we found that baseline fibrosis(p&lt;0.05), history of stroke(p&lt;0.05), vascular diseases(p&lt;0.05), and LA volume(p&lt;0.01) were independent predictors of AF burden. In men, on univariate analysis, age(p&lt;0.01), baseline fibrosis(p&lt;0.01), hyperlipidemia(p&lt;0.01) and LA volume(p&lt;0.01) were positively correlated with AF burden. After conducting a multivariate analysis, only LA volume (p&lt;0.01) and age(&lt;0.01) continued to be significantly related(Table 1). Conclusion: Sex-specific management strategies are crucial for addressing AF, as our study demonstrates a significant impact of sex on predicting AF burden monitored by a single-lead handheld smartphone ECG device.

Abstract 18093: History of Stroke as a Predictor of High Left Atrial Fibrosis in Patients With Persistent Atrial Fibrillation

Introduction: The relationship between left atrial (LA) remodeling and ischemic stroke (IS) risk in patients with atrial fibrillation (AF) is well-established. The DECAAF II trial is the largest MRI-based, multicenter, randomized study conducted on persistent AF patients. Hypothesis: Our research investigates whether a history of stroke correlates with the extent of atrial fibrosis, as determined by late gadolinium enhancement magnetic resonance imaging (LGE-MRI), among the DECAAF II trial population. Methods: Patients with persistent AF who underwent LGE-MRI were enrolled and categorized into two cohorts: those with a history of stroke and those without. Covariates were adjusted using propensity score matching, and atrial fibrosis was compared between groups. Participants were then subdivided according to three baseline atrial fibrosis cut-off values: ≥ 15%, ≥ 20%, ≥ 25%. Univariate logistic regression and adjusted multivariate analyses were applied to evaluate the impact of clinical characteristics and risk factors on baseline fibrosis. Results: From the 843 patients involved in the DECAAF II trial, 70 (8.3%) had a stroke history. Those with stroke history had higher rates of hypertension, diabetes, and hyperlipidemia. Seventy patients without a stroke history were matched to stroke patients using propensity score analysis, revealing a significantly higher fibrosis in the stroke group (20.2% vs. 8.1%, p = 0.017). Increasing age significantly predicted all three baseline fibrosis categories (≥15%, ≥20%, ≥25%). Notably, stroke history was as a predictor of baseline fibrosis ≥25%, even after adjusting for other risk factors and clinical characteristics (OR = 1.98 [1.14-3.43], p = 0.01). Conclusions: There is a significant correlation between high left atrial fibrosis level and an increased risk of ischemic stroke in patients with persistent atrial fibrillation. This suggests that atrial fibrosis may provide insights into stroke risk classification.

Abstract 19134: Association Between CHA 2 DS 2 -VASc and LA Volume Index: Insights From DECAAF II

Introduction: LA Volume is strongly associated with atrial fibrillation (AF) and underlying atrial myopathy. The CHA 2 DS 2 -VASc score predicts stroke risk in patients with AF. The aim of this study is to investigate the relationship between the two. Methods: In this subanalysis of the DECAAF II trial, patients with persistent AF undergoing first-time catheter ablation underwent a baseline late gadolinium enhancement magnetic resonance imaging (LGE-MRI) within one month prior to ablation. LA Volume Index (LAVI) was defined as LA Volume on the MRI prior to ablation divided by body surface area ( mL/m2 ). The CHA2 DS2 -VASc score was also calculated at baseline prior to ablation. Analysis of Variance (ANOVA) test and linear regression were used to study the association between the two. Results: 815 patients were included, (78.9% males, mean age 62.7 ± 9.1 years) (table). The mean LAVI was 62.2 ± 18.9 mL/m2, and mean CHA2 DS2 -VASc score was 1.7 ± 1.27. The ANOVA test showed significant differences between group (F = 7.71, p &lt;0.001). For every point increase in CHA2 DS2 -VASc score, LAVI increases by 3 (LAVI = 2.99 * CHA2 DS2 -VASc + 57; p &lt;0.001) (figure). Conclusions: Our data suggests that structural remodeling in patients with AF is likely driven by multiple factors. There was a clear association between CHA2 DS2 -VASc score and higher LAVI. Serial analysis of LA Volume at different time points is needed to further understand the impact of individual comorbidities on LA volume dilation.

Abstract 14417: Regional 4D Cardiac Magnetic Resonance Strain Associates With Late Gadolinium Enhancement in Duchenne Muscular Dystrophy Associated Cardiomyopathy

Introduction: Cardiomyopathy (CM) is the leading cause of death in Duchenne muscular dystrophy (DMD). Onset and clinical progression are varied. Cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) can detect fibrofatty replacement prior to decreased left ventricular ejection fraction (LVEF) but requires administration of gadolinium contrast agents. Non-contrast methods to characterize CM onset and progression could decrease scan time and exposure to gadolinium. Using a novel 4D (3D+time) regional strain analysis method, we hypothesized that the regional magnitude of surface area strain (E a ) would be significantly decreased in DMD patients with LGE and that E a would correlate with decreased LVEF . Methods: Short-axis cine CMR images for 43 pediatric DMD patients (13.6 ± 4.2 years) were compiled into 4D sequences for regional strain analysis (Fig. 1A). For all 4D sequences, epi- and endocardial borders were segmented across one cardiac cycle for kinematic analysis using a custom-built MATLAB graphical user interface (MathWorks, Natick, MA). Regional E a was measured by determining the relative change in the localized 4D endocardial surface mesh compared to end-diastole. Unpaired t-test and Spearman’s rho were used to determine statistical significance and correlation. Results: DMD patients had a range of CM severity: 13 with reduced LVEF of &lt;55% (30% of total) and 28 with LGE (65% of total). Peak E a was significantly different between patients with and without LGE in the basal inferior ( p =0.022), basal inferolateral ( p &lt;0.001), basal anterolateral ( p =0.002), mid inferolateral ( p =0.004), mid anterolateral ( p =0.018), and apical anterior ( p &lt;0.032), regions (Fig.1B). Basal E a also correlated significantly with LVEF ( rho =-0.45, p&lt; 0.001; Fig. 1C). Conclusion: Regional E a from 4D CMR in DMD was reduced in patients with LGE compared to those without LGE particularly in the basolateral regions. Peak basal E a correlated with a reduction in LVEF. LVEF.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy.

Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP. Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05). Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

Left ventricular entropy is a novel predictor of major adverse cardiac events (MACE) in patients with coronary atherosclerosis: a multi-center study.

To investigate the incremental prognostic value of left ventricular (LV) entropy in a large multi-center population with coronary atherosclerotic heart disease (CAD). Current risk stratification of patients with CAD is imprecise and not accurate enough. A total of 314 CAD patients who underwent cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) at two medical centers in China between October 2015 and July 2022 were included in this study. Additionally, the 193 patients under 3.0-T field also underwent CMR T1 mapping. LV entropy and extracellular volume (ECV) were calculated from the LGE image of LV myocardium, and major adverse cardiac events (MACEs) were analyzed. Among 314 patients, 110 experienced MACE during a median follow-up of 13months. The risk of MACE was significantly increased in the high entropy group (log-rank p < 0.001). Entropy maintained an independent association with MACE in a multivariable model including left ventricular ejection fraction (LVEF) and LGE (HR = 1.78; p = 0.001). In addition, the primary endpoint events prognostic value was significantly improved by adding LV entropy to the baseline multivariable model (C-statistic improvement: 0.785-0.818, Delong test: p = 0.001). Similarly, among 193 3.0-T field patients, adding LV entropy to the multivariable baseline model significantly improved the prognostic value of the model for MACE (C-statistic improvement: 0.820-0.898, Delong test: p = 0.004). CMR-assessed LV entropy is a powerful independent predictor of MACE in patients with CAD, incremental to common clinical and CMR risk factors, including LVEF, LGE, Native T1, and ECV. Left ventricular entropy is a powerful independent predictor of major adverse cardiac events in patients with coronary atherosclerotic heart disease, incremental to common clinical and cardiac magnetic resonance risk factors. • Left ventricular entropy, a novel cardiac magnetic resonance parameter of myocardial heterogeneity, demonstrated a robust prognostic association with major adverse cardiac events beyond guideline-based, clinical risk markers. • Entropy can have an important role in the primary prevention of major adverse cardiac events in patients with coronary atherosclerotic heart disease. • Compared with late gadolinium enhancement, extracellular volume, and native T1, entropy could be used to more comprehensively characterize the heterogeneity of left ventricular myocardium.

Institutional experience report on the target contouring workflow in the radiotherapy department for stereotactic arrhythmia radioablation delivered on conventional linear accelerators.

In stereotactic arrhythmia radioablation (STAR), the target is defined using multiple imaging studies and amultidisciplinary team consisting of electrophysiologist, cardiologist, cardiac radiologist, and radiation oncologist collaborate to identify the target and delineate it on the imaging studies of interest. This report describes the workflow employed in our radiotherapy department to transfer the target identified based on electrophysiology and cardiology imaging to the treatment planning image set. The radiotherapy team was presented with an initial target in cardiac axes orientation, contoured on awideband late gadolinium-enhanced (WB-LGE) cardiac magnetic resonance (CMR) study, which was subsequently transferred to the computed tomography (CT) scan used for treatment planning-i.e., the average intensity projection (AIP) image set derived from a4DCT-via an axial CMR image set, using rigid image registration focused on the target area. The cardiac and the respiratory motion of the target were resolved using ciné-CMR and 4D CT imaging studies, respectively. The workflow was carried out for 6patients and resulted in an internal target defined in standard anatomical orientation that encompassed the cardiac and the respiratory motion of the initial target. An image registration-based workflow was implemented to render the STAR target on the planning image set in aconsistent manner, using commercial software traditionally available for radiation therapy.

Prognostic role of atrial fibrillation in patients with non-compaction cardiomyopathy

Aim. To evaluate the prognostic role of atrial fibrillation (AF) as a predictor of adverse events and outcomes in a cohort of patients with non-compaction cardiomyopathy (NCCM).Material and methods. We examined 216 patients with NCCM (140 men and 76 women, median age, 39 (30; 50) years). In addition to traditional clinical methods, all patients underwent late gadolinium-enhanced cardiac magnetic resonance imaging (MRI). The endpoints of the study included progression of NYHA class III heart failure (HF) with the need for hospitalization, ventricular tachyarrhythmias, and thromboembolic events (TEEs).Results. There were 54 out of 216 (23,6%) patients with AF, of which 18 had paroxysmal AF, 16 — persistent AF, and 20 — permanent AF. During the follow-up period (median follow-up, 36 (6; 72) months), 98 out of 216 (45,4%) patients with NCCM had adverse events and outcomes as follows: 16 (7,4%) had ventricular tachyarrhythmias, of which 12 (5,6%) — sudden cardiac death with successful resuscitation and implantation of an implantable cardioverter-defibrillator; 62 (28,7%) patients had NYHA III-IV class HF progression; 20 (9,3%) patients had TEEs. The rate of adverse cardiac events was significantly higher in patients with AF (74,1% vs 35,8%, χ2=23,93, p&lt;0,001) compared with patients without AF, including the incidence of TEEs (20,4% vs 5,6%, χ2=10,58, p=0,002) and HF progression to class III (46,3% vs 22,8%, χ2=10,9, p=0,002).Multivariate analysis showed that the following most significant predictors of HF progression risk: left ventricular ejection fraction (LVEF) &lt;50% according to cardiac MRI (hazard ratio (HR), 95,8; 95% confidence interval (CI), 10,2 -898,6; p=0,0001), presence of AF (HR, 8,2; 95% CI, 2,2-31,3; p=0,0022) and left atrial volume index (LAVI) &gt;43 ml/m2 (HR, 5,2; 95% CI, 2,1-12,8; p=0,0004); predictors of TEE risk were the presence of AF (HR, 6,5; 95% CI, 2,0-20,8; p=0,0020) and LAVI &gt;43 ml/m2 (HR, 6,0; 95% CI, 1,8-19,7; p=0,036). No association of AF with ventricular tachyarrhythmias was found in the study cohort of patients with NCCM. Predictors of ventricular tachyarrhythmias were LVEF &lt;50% (HR, 4,5; 95% CI, 2,950,4; p=0,0241) and the presence of non-sustained ventricular tachycardia (HR, 3,5; 95% CI, 1,3-9,3 p=0,0139).Conclusion. The present study shows that, along with the traditional predictor of adverse events in patients with NCCM (LVEF &lt;50%), the identified additional predictors (AF and LAVI &gt;43 ml/m2) can be used to identify patients at high risk of complicated NCCM for the timely prevention and treatment.