Contrast Cardiac Magnetic Resonance Research Articles

Usefulness of Native T1 in Cardiac Magnetic Resonance Imaging and Echocardiographic Strain Parameters for Detecting Early Cardiac Involvement in Fabry Cardiomyopathy.

Non-invasive diagnosis of disease stage in Fabry cardiomyopathy with multimodality imaging is pivotal when deciding on the appropriate time to initiate enzyme replacement therapy. However, this approach has not been well established. We enrolled 14 patients with Fabry disease. All patients were evaluated using echocardiography and contrast cardiac magnetic resonance (CMR), and were divided into either an early-stage group without left ventricular hypertrophy (LVH; wall thickness >12 mm) or late gadolinium enhancement (LGE; n=7; median age 37 years; 4 female), or an advanced-stage group with LVH and/or LGE (n=7; median age 66 years; 7 female). Strain data from echocardiography and T1 mapping on CMR were compared between the groups. In the advanced-stage group, all strain data were impaired. In the early-stage group, localized longitudinal strain in the basal posterolateral segment was already reduced but both localized and global circumferential strain remained preserved. On CMR analysis, global and localized native T1 shortening were observed in the early-stage group, but were pseudo-normalized in the advanced-stage group. In logistic regression analysis, localized circumferential strain had significant diagnostic value for differentiating between early- and advanced stage (P=0.037) and significantly improved the predictive power of the model containing localized native T1 in CMR. A combination of localized native T1 in CMR and echocardiographic strain parameters could be useful for staging Fabry cardiomyopathy.

Left atrial diastasis strain slope is a marker of hemodynamic recovery in post-ST elevation myocardial infarction: the Laser Atherectomy for STemi, Pci Analysis with Scintigraphy Study (LAST-PASS).

Left atrial (LA) mechanics are strongly linked with left ventricular (LV) filling. The LA diastasis strain slope (LADSS), which spans between the passive and active LA emptying phases, may be a key indicator of the LA-LV interplay during diastole. This study aimed to investigate the LA-LV interdependencies in post-ST elevation myocardial infarction (STEMI), with particular focus on the LADSS. Patients with post-anterior STEMI who received primary percutaneous coronary intervention underwent contrast cardiac magnetic resonance imaging (MRI) during acute (5-9 days post-STEMI) and chronic (at 6 months) phases. The LADSS was categorized into three groups: Groups 1, 2, and 3 representing positive, flat, and negative slopes, respectively. Cross-sectional correlates of LADSS Group 2 or 3 compared to Group 1 were identified, adjusting for demographics, LA indices, and with or without LV indices. The associations of acute phase LADSS with the recovery of LV ejection fraction (LVEF) and scar amount were investigated. Sixty-six acute phase (86.4% male, 63.1 ± 11.8 years) and 59 chronic phase cardiac MRI images were investigated. The distribution across LADSS Groups 1, 2, and 3 in the acute phase was 24.2%, 28.9%, and 47.0%, respectively, whereas in the chronic phase, it was 33.9%, 22.0%, and 44.1%, respectively. LADSS Group 3 demonstrated a higher heart rate than Group 1 in the acute phase (61.9 ± 8.7 vs. 73.5 ± 11.9 bpm, p < 0.01); lower LVEF (48.7 ± 8.6 vs. 41.8 ± 9.9%, p = 0.041) and weaker LA passive strain rate (SR) (-1.1 ± 0.4 vs. -0.7 [-1.2 to -0.6] s-1, p = 0.037) in the chronic phase. Chronic phase Group 3 exhibited weaker LA passive SR [relative risk ratio (RRR) = 8.8, p = 0.012] than Group 1 after adjusting for demographics and LA indices; lower LVEF (RRR = 0.85, p < 0.01), higher heart rate (RRR = 1.1, p = 0.070), and less likelihood of being male (RRR = 0.08, p = 0.058) after full adjustment. Acute phase LADSS Groups 2 and 3 predicted poor recovery of LVEF when adjusted for demographics and LA indices; LADSS Group 2 remained a predictor in the fully adjusted model (β = -5.8, p = 0.013). The LADSS serves both as a marker of current LV hemodynamics and its recovery in post-anterior STEMI. The LADSS is an important index of LA-LV interdependency during diastole. https://clinicaltrials.gov/, identifier NCT03950310.

Abstract 18984: Artificial Intelligence-Based Automated Left Ventricle Mass Quantification From Non-Contrast Cardiac CT Scans: Correlation With Contrast CT and Cardiac MRI

Background: Non-contrast CT scans are currently not used to assess left ventricular myocardial mass (LV mass), which is usually evaluated with contrast CT or cardiac magnetic resonance (CMR). We aimed to assess the feasibility of LV mass estimation from non-contrast CT calcium scans using an artificial intelligence (AI) approach and compare it to measurements from contrast CT and CMR. Methods: A total of 316 patients (Age: 57.1±16.7, 53.2% male) who underwent coronary CT angiography (with non-contrast calcium CT and contrast CT) and CMR were included. The median interval between CT and CMR was 22 days (IQR: 3-76). An nn-Unet AI model (Total Segmentator), previously trained on data from independent sites, automatically segmented non-contrast CT structures including the myocardium. LV mass was also measured from contrast CT and CMR by experts during routine clinical reporting. Results: The AI segmentation took ~22 seconds per case. There was no significant difference in LV mass between the AI and contrast CT (136.5±55.3 vs. 139.6±58.0 g, p=0.114). An excellent correlation was observed between AI and contrast CT (r=0.84, p&lt;0.001) (Figure). Bland-Altman analysis showed a minimal bias of 3.15. Compared to CMR, both AI and non-contrast CT showed higher LV mass (136±55.3, 139.6±58.0 vs. 127.1±53.1 g, respectively, both p&lt;0.001). The correlations of AI and contrast CT with CMR were excellent with no significant differences. (r= 0.86 and 0.85, both p&lt;0.001). Bland-Altman analysis indicated small bias toward higher LV mass with AI and contrast CT (-9.35 and -12.5, respectively) compared to CMR. Conclusions: The AI-based automated LV mass from non-contrast CT showed excellent correlations and minimal biases when compared to LV mass measured from contrast CT and CMR. This fully automated measure could be applied for routine LV mass evaluation in patients with a non-contrast CT scan, providing an additional biomarker previously thought not measurable by this modality.

Identifying Mitral Valve Prolapse at Risk for Arrhythmias and Fibrosis From Electrocardiograms Using Deep Learning

BackgroundMitral valve prolapse (MVP) is a common valvulopathy, with a subset developing sudden cardiac death or cardiac arrest. Complex ventricular ectopy (ComVE) is a marker of arrhythmic risk associated with myocardial fibrosis and increased mortality in MVP. ObjectivesThe authors sought to evaluate whether electrocardiogram (ECG)-based machine learning can identify MVP at risk for ComVE, death and/or myocardial fibrosis on cardiac magnetic resonance (CMR) imaging. MethodsA deep convolutional neural network (CNN) was trained to detect ComVE using 6,916 12-lead ECGs from 569 MVP patients from the University of California-San Francisco between 2012 and 2020. A separate CNN was trained to detect late gadolinium enhancement (LGE) using 1,369 ECGs from 87 MVP patients with contrast CMR. ResultsThe prevalence of ComVE was 28% (160/569). The area under the receiver operating characteristic curve (AUC) of the CNN to detect ComVE was 0.80 (95% CI: 0.77-0.83) and remained high after excluding patients with moderate-severe mitral regurgitation [0.80 (95% CI: 0.77-0.83)] or bileaflet MVP [0.81 (95% CI: 0.76-0.85)]. AUC to detect all-cause mortality was 0.82 (95% CI: 0.77-0.87). ECG segments relevant to ComVE prediction were related to ventricular depolarization/repolarization (early-mid ST-segment and QRS from V1, V3, and III). LGE in the papillary muscles or basal inferolateral wall was present in 24% patients with available CMR; AUC for detection of LGE was 0.75 (95% CI: 0.68-0.82). ConclusionsCNN-analyzed 12-lead ECGs can detect MVP at risk for ventricular arrhythmias, death and/or fibrosis and can identify novel ECG correlates of arrhythmic risk. ECG-based CNNs may help select those MVP patients requiring closer follow-up and/or a CMR.

T1 mapping in population ageing

Abstract Funding Acknowledgements Type of funding sources: None. Background The world’s population is ageing: every country is experiencing growth in both the size and the proportion of older people. Common health states in older age mainly include cardiovascular disease. To ensure that our health system is ready to face this demographic shift, we investigated native and post-contrast T1 mapping as a quantitative method to appraise its clinical potential in older people. Purpose This article aimed to provide reference values of T1 mapping for quantification of the expansion of the extracellular matrix in older people. Methods We retrospectively selected subjects ranged in age from 86 to 101 years old that underwent contrast cardiac magnetic resonance (CMR). All subjects were imaged on a 1.5 T system. T1 measurements were performed with a Modified Look Lockers Inversion (MOLLI) recovery sequence. Regions of interest (ROI) were drawn in the left ventricle for blood T1 measurement and in the interventricular septum. We used T1 data obtained before and after contrast injection. We also measured the volume and function of both ventricles. Rho di Spearman was used for correlations. Results We analysed 29 patients (mean age 88.58±3.13 years old). Mean value of T1 in the blood pool (T1bp) was 1647.43±107.66 before contrast and 357.18±63.94 after contrast. Mean value of T1 in the septum (T1s) was 1012.86±38.41 before contrast and 488.68±69.29 after contrast. Left ventricle (LV) EDVI was 48.11±15.29 ml/m2 and ESVI 16.49±8.59 ml/m2, LV ejection fraction (EF) and stroke volume (SV) were 66.38±9.65 % and 52.39±18.84 ml respectively. Right ventricle (RV) EDVI was 46.44±13.19 ml/m2 and ESVI 16.97±5.93 ml/m2, LV ejection fraction (EF) and stroke volume (SV) were 63.46±8.65 % and 49.29±18.63 ml respectively. A significant negative correlation was found between age and T1s before contrast (r=-0.405 and p = 0.015). Positive correlations were found also between T1s before contrast and LV volumes. Conclusions This study shows a correlation between T1 mapping and population ageing.

Accuracy of pulmonary venous flow quantification by 2D phase contrast cardiac magnetic resonance

Abstract Funding Acknowledgements Type of funding sources: None. Background Determination of pulmonary venous flow by cardiac magnetic resonance (CMR) is frequently required in patients with complex congenital heart disease (CHD) lesions. Although new advanced imaging techniques like 4D flow are increasingly available, standard 2D phase contrast (2DPC) sequences remain the most frequently used method for quantification of flow. However, little is known on the accuracy of 2DPC flow measurements in the pulmonary veins. Purpose This study therefore aims to investigate the accuracy of pulmonary venous flow quantification by 2DPC. Methods Patients with CHD underwent a CMR on a 1.5T scanner. 2DPC flow sequences (typical temporal resolution 35–50ms, inplane spatial resolution 1.3–1.8 mm2, VENC 80–100) were acquired in the ascending aorta (AA), main, right and left pulmonary arteries (MPA, RPA, LPA), as well as left (LPV) and right (RPV) pulmonary veins. Pulmonary venous flow was compared to pulmonary arterial flow in all patients and to aortic flow in patients without left to right (L-R) shunt using Bland-Altman plots and Pearson’s correlations. Results Twenty CHD patients (age 27±3, range 7; 53 years, 7 women, tetralogy of Fallot N=7, Ross operation N=1; Fontan N=4, transposition of great arteries N=2, atrial septal defect N=2, Turner syndrome 1, Ebstein N=1, valvulopathies N=2) were included. Table 1 shows absolute flow values of the different vessels. Bland-Altman analyses and correlations (Table 2) showed a good agreement of total pulmonary venous (PV) to flow in the ascending aorta (group without shunt) and the sum of flow of both branch pulmonary arteries. However, agreement of total PV with MPA flow as well as of LPV and RPV with the respective branch pulmonary artery flow was reduced. Conclusions Total PV flow determined by 2DPC shows a good agreement with flow in the ascending aorta and the sum of the branch pulmonary arteries. Flow turbulences due to the pathologies of the right ventricular outflow tract probably contribute to the reduced agreement of total PV and MPA flow. However, the reduced agreement of the flow in left/right pulmonary veins and their respective branch pulmonary arteries underlines the need for newer advanced flow quantification techniques to improve accuracy of pulmonary venous flow measurements.

Addressing Deep Learning Model Calibration Using Evidential Neural Networks And Uncertainty-Aware Training.

In terms of accuracy, deep learning (DL) models have had considerable success in classification problems for medical imaging applications. However, it is well-known that the outputs of such models, which typically utilise the SoftMax function in the final classification layer can be over-confident, i.e. they are poorly calibrated. Two competing solutions to this problem have been proposed: uncertainty-aware training and evidential neural networks (ENNs). In this paper we perform an investigation into the improvements to model calibration that can be achieved by each of these approaches individually, and their combination. We perform experiments on two classification tasks: a simpler MNIST digit classification task and a more complex and realistic medical imaging artefact detection task using Phase Contrast Cardiac Magnetic Resonance images. The experimental results demonstrate that model calibration can suffer when the task becomes challenging enough to require a higher capacity model. However, in our complex artefact detection task we saw an improvement in calibration for both a low and higher capacity model when implementing both the ENN and uncertainty-aware training together, indicating that this approach can offer a promising way to improve calibration in such settings. The findings highlight the potential use of these approaches to improve model calibration in a complex application, which would in turn improve clinician trust in DL models.

A computational study of aortic reconstruction in single ventricle patients.

Patients with hypoplastic left heart syndrome (HLHS) are born with an underdeveloped left heart. They typically receive a sequence of surgeries that result in a single ventricle physiology called the Fontan circulation. While these patients usually survive into early adulthood, they are at risk for medical complications, partially due to their lower than normal cardiac output, which leads to insufficient cerebral and gut perfusion. While clinical imaging data can provide detailed insight into cardiovascular function within the imaged region, it is difficult to use these data for assessing deficiencies in the rest of the body and for deriving blood pressure dynamics. Data from patients used in this paper include three-dimensional, magnetic resonance angiograms (MRA), time-resolved phase contrast cardiac magnetic resonance images (4D-MRI) and sphygmomanometer blood pressure measurements. The 4D-MRI images provide detailed insight into velocity and flow in vessels within the imaged region, but they cannot predict flow in the rest of the body, nor do they provide values of blood pressure. To remedy these limitations, this study combines the MRA, 4D-MRI, and pressure data with 1D fluid dynamics models to predict hemodynamics in the major systemic arteries, including the cerebral and gut vasculature. A specific focus is placed on studying the impact of aortic reconstruction occurring during the first surgery that results in abnormal vessel morphology. To study these effects, we compare simulations for an HLHS patient with simulations for a matched control patient that has double outlet right ventricle (DORV) physiology with a native aorta. Our results show that the HLHS patient has hypertensive pressures in the brain as well as reduced flow to the gut. Wave intensity analysis suggests that the HLHS patient has irregular circulatory function during light upright exercise conditions and that predicted wall shear stresses are lower than normal, suggesting the HLHS patient may have hypertension.

Four-dimensional flow cardiac magnetic resonance assessment of left ventricular diastolic function.

Left ventricular diastolic dysfunction is a major cause of heart failure and carries a poor prognosis. Assessment of left ventricular diastolic function however remains challenging for both echocardiography and conventional phase contrast cardiac magnetic resonance. Amongst other limitations, both are restricted to measuring velocity in a single direction or plane, thereby compromising their ability to capture complex diastolic hemodynamics in health and disease. Time-resolved three-dimensional phase contrast cardiac magnetic resonance imaging with three-directional velocity encoding known as ‘4D flow CMR’ is an emerging technology which allows retrospective measurement of velocity and by extension flow at any point in the acquired 3D data volume. With 4D flow CMR, complex aspects of blood flow and ventricular function can be studied throughout the cardiac cycle. 4D flow CMR can facilitate the visualization of functional blood flow components and flow vortices as well as the quantification of novel hemodynamic and functional parameters such as kinetic energy, relative pressure, energy loss and vorticity. In this review, we examine key concepts and novel markers of diastolic function obtained by flow pattern analysis using 4D flow CMR. We consolidate the existing evidence base to highlight the strengths and limitations of 4D flow CMR techniques in the surveillance and diagnosis of left ventricular diastolic dysfunction.

Phase contrast cardiac magnetic resonance imaging versus transoesophageal echocardiography for the evaluation of feasibility for transcatheter closure of atrial septal defects

BackgroundThis prospective study was aimed at comparing phase contrast cardiac magnetic resonance imaging (PC-CMR) with 2D transoesophageal echocardiography (TEE) for determining potential candidature for transcatheter closure in ostium secundum ASD (OS-ASD) patients. We included consecutive adult patients with OS-ASD for the evaluation of feasibility for transcatheter closure using 2D-TEE and PC-CMR over a period of 2 years. Patients who fulfilled the conventional criteria for transcatheter closure, i.e. maximum ASD diameter ≤ 34 mm, adequate rims (≥ 5 mm, except for anterosuperior rim), and normal pulmonary venous drainage on both imaging modalities, were taken for device closure. In patients where there was discrepancy in the measurements of ASD diameter or rim size, making them eligible for device closure on one imaging modality and ineligible on the other hand, provisional device closure was attempted. All patients who underwent transcatheter closure were followed up to 6 months to rule out any complications.ResultsA total of 58 patients (mean age 35.93 ± 10.59 years) were enrolled in the study. Overall, there was significant positive correlation between 2D-TEE and CMR measurements of maximal ASD diameter and rim size (p < 0.001). However, TEE significantly underestimated maximal ASD diameter and posteroinferior rim size in comparison with CMR (p = 0.013 and p = 0.023, respectively). 46 (79.3%) patients were suitable for transcatheter closure on CMR, while 44 (75.9%) were eligible on TEE. Transcatheter closure was attempted in 48 patients based on imaging findings and was successful in 46 (95.8%) patients. Device closure was unsuccessful in 2 patients with defect size < 34 mm on TEE but > 34 mm on CMR. Among 7 patients with deficient posteroinferior rim on TEE, 5 had sufficient rim on CMR and underwent successful transcatheter closure. CMR detected anomalous pulmonary venous drainage in one patient which was missed on TEE, hence excluding the patient from transcatheter closure. Mean device size was 28.3 ± 7.4 mm and correlated more strongly with the defect dimensions on PC-CMR (r = 0.85, p < 0.001) compared to TEE (r = 0.71, p = 0.02).ConclusionsPC-CMR may to be superior to 2D-TEE for the preprocedural planning and feasibility assessment for transcatheter closure in adult patients with ostium secundum ASD.

A Risk Score to Diagnose Cardiac Involvement and Provide Prognosis Information in Patients at Risk of Cardiac Light-Chain Amyloidosis

BackgroundCardiac light-chain amyloidosis (AL CA) portends poor prognosis. Contrast cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) imaging is an important tool in recognizing AL CA. But contraindications to contrast CMR would significantly restrict its clinical application value. Our study aims to construct a convenient risk score to help identify cardiac involvement in patients at risk of AL CA. Moreover, we also investigate whether this risk score could provide prognosis information.Materials and MethodsSixty-three patients at risk of AL CA were retrospectively included in our study. Basic clinical characters, lab results, 12-lead electrocardiogram data, and cardiac magnetic resonance image data were collected. AL CA was diagnosed according to typical CA LGE pattern. Logistic analysis was used to figure out predictive parameters of AL CA and their β coefficients, further constructing the risk score. Receiver operating characteristics (ROC) curve was used to find the cut-off point best distinguishing AL CA+ from AL CA–patients. Bootstrapping was used for internal validation. All patients were divided into high-risk and low-risk group according to the diagnostic cut-off point, and followed up for survival information. Kaplan-Meier plots and log-rank test were performed to analyze if this score had prognostic value.ResultsThe risk score finally consisted of 4 parameters: pericardial effusion (PE) (1 point), low electrocardiographic QRS voltages (LQRSV) (1 point), CMR-derived impaired global radial strain (GRS) (<15.14%) (1 point) and increased left ventricular maximum wall thickness (LVMWT) (>13 mm) (2 points). Total score ranged from 0 to 5 points. A cut-off point of 1.5 showed highest accuracy in diagnosing AL CA with an AUC of 0.961 (95% CI: 0.924–0.997, sensitivity: 90.6%, specificity: 83.9%). Kaplan-Meier plots and log-rank test showed that the high-risk group had significantly poor overall survival rates.ConclusionIn patients at risk of AL CA, a risk score incorporating the presence of PE, LQRSV, and CMR-derived impaired GRS and increased LVMWT is predictive of a diagnosis of AL CA by LGE criteria. This risk score may be helpful especially when contrast CMR is not available or contraindicated, and further studies should be considered to validate this score.

813 The added value of transthoracic three dimensional echocardiography in apical hypertrophic cardiomyopathy

Abstract We present the case of a 73-year-old patient with a recent diagnosis of hypertrophic cardiomyopathy (HCM). He was asymptomatic and has no family history of sudden cardiac death (SCD), syncope or ventricular arrhythmias. An echocardiogram performed at the moment of diagnosis (2020), showed left ventricular (LV) asymmetric apical hypertrophy with maximal wall thickness of 21 mm. Cardiac magnetic resonance (CMR) confirmed LV apical hypertrophy with mid-ventricular obliteration, and late gadolinium enhancement in the apical segments, without wall motion abnormalities present at rest. According to 2014 ESC guidelines, his calculated risk score for sudden cardiac death was low (1.23% at 5 years). On 2021, a comprehensive transthoracic echocardiographic examination including advanced techniques (three-dimensional echo-3DE-, and two-dimensional speckle-tracking-2DSTE) was done as part of his routine follow-up in our cardiomyopathy outpatient clinic. The echo study showed an asymmetric pattern of LV hypertrophy with a maximal wall thickness of 21 mm at the level of the anterolateral apical segment, normal LV volumes (end-diastolic volume 55 mL/m2) and ejection fraction (69%) by 3DE. LV longitudinal strain analysis by 2DSTE showed impaired LV myocardial deformation mainly at the apical LV segments (GLS = −13.6%). There was evidence of dynamic intracavitary obstruction (maximal gradient 32 mmHg at rest and raised to 52 mmHg during Valsalva manoeuvre). 3DE views of the LV (both multi-slice display and 3D rendered image) allowed to avoid foreshortening of the LV apical views, and to appreciate the actual wall motion at the real LV apex. They revealed a LV apical aneurysm which was not detected in the conventional LV-focused apical 2D views (Figure 1A and B). Apical hypertrophic cardiomyopathy (ApHCM) is a variant of HCM that is characteristic of focal thickening of the LV apical myocardium and was reported to have a more benign course than other non-apical forms. However, the presence of LV aneurysm in ApHCM patients is associated with an increased risk for ventricular arrhythmias, sudden cardiac death and thromboembolism. Accordingly, the detection of apical LV aneurysms has significant impact on patient management. Guidelines recommend the use of contrast echocardiography or CMR when the apical region of the LV is suboptimally visualized by conventional 2D echocardiography. However, contrast echocardiography may still be affected by apical foreshortening resulting in suboptimal accuracy, as it is a 2D technique. On the other end, CMR may be contraindicated or not widely available for routine yearly follow-up for all HCM patients requiring regular imaging follow-up. Our clinical case emphasizes the added value of 3DE to increase the sensitivity of transthoracic echocardiography in detecting apical LV aneurysms in patients with apical HCM with important clinical implications for the management of the patient. 813 Figure 1(A) 2D 4chamber-view showing maximal wall thickness in the apical segments (21 mm) with apical obliteration. At a first evaluation, apical aneurism is not easily detected. (B) 4D rendering of the apex showing the apical aneurism.

430 Diagnosis and management of a case of biventricular arrhythmogenic cardiomyopathy: a case report

Abstract Arrhythmogenic cardiomyopathy (ACM) is a genetically determined heart muscle disorder characterized by fibro-fatty replacement of myocardium which may affect the right ventricle (‘dominant right’ variant), the left ventricle (‘dominant left’ variant) or both (‘biventricular disease’ variant). Despite of ACM is one of the main causes of sudden cardiac death (SCD) in young people and athletes as well, the diagnosis of this complex clinical entity still remains a challenge. We report on a case of a 29 years old non-athletic woman with family history of SCD and a long-standing personal history of palpitations leading to frequent accesses to the Accident &amp; Emergency Department. Her echocardiogram was normal while twelve leads ECG revealed negative T waves in the right precordial leads (V1–V3) and post-excitation epsilon waves. ECG Holter monitoring recorded frequent (up to 17 000 in 24 h) polymorphic premature ventricular contractions (PVCs) seldom organized in couplets or triplets. She was followed-up in our clinic and started on Propanolol 40 mg bid with slight relief of symptoms and reduction of PVCs. Cardiac magnetic resonance (CMR) showed regional dyskinesia of both ventricles and RV dilatation. Moreover, tissue characterization findings revealed the presence of diffuse subepicardial late gadolinium enhancement (LGE) of the LV. Genetic analysis was performed and a variant of uncertain significance (VUS) in Desmoplakin was identified. Non sustained monomorphic ventricular tachycardia was induced during electrophysiologic study by programmed ventricular stimulation. In light of these results, we diagnosed biventricular ACM and, after carefully discussion with the patient, a subcutaneous implantable cardioverter defibrillator (ICD) was implanted. The present case should be a persisting reminder that must be considered more than just a single diagnostic tool when dealing with arrhythmic presentations especially in young patients and the importance of contrast CMR along with genetic testing in order to aid clinicians in the demanding selection of the best candidates for ICD implantation.

Abstract 9970: Prevalence of ECG Abnormalities and Association with Arrhythmic Risk and Myocardial Fibrosis in a Large Cohort of Patients with Mitral Valve Prolapse

Background: Inverted or biphasic T-waves (IBTWs) in the inferior leads on a 12-lead electrocardiogram (ECG) have been previously described in small, retrospective samples of MVP with sudden cardiac arrest (SCA) or sudden cardiac death (SCD). However, prior studies are limited by selection of bileaflet involvement, referral bias or targeted autopsies. Moreover, the association of IBTWs with focal fibrosis remains poorly defined. Objective: To assess the rates of IBTWs and their association with arrhythmic risk and late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) in an unselected, longitudinal MVP cohort. Methods: We reviewed available 12-lead ECGs from a cohort of 570 MVP patients with clinical and ambulatory ECG or telemetry monitoring evaluated at the University of California San Francisco between 2012 and 2020. IBTWs were considered clinically relevant if present in at least 2 of 3 inferior ECG leads. Complex ventricular ectopy (ComVE) was defined as &gt;5% burden of premature ventricular contractions, bigeminy, or non-sustained ventricular tachycardia. SCD cases were identified through the National Death Index. In a subset of 86 (15%) patients with available contrast CMR, we assessed the presence and location of LGE. Results: Among 570 MVP patients (52% male, mean age 64±17), 86 (15%) had IBTWs, 160 (28%) had ComVE, and 26 (5%) had severe arrhythmic events (2 sustained VT, 13 SCA, and 11 SCD). Of these 26, 15 (58%) were bileaflet. Rates of IBTWs were similar between MVPs with severe arrhythmic events (9/26, 35%), ComVE (28/160, 18%), and no ventricular arrhythmia (58/410, 14%) ( p= 0.33). Among MVPs with contrast CMR, there were higher rates of IBTWs in those with LGE (papillary muscles or basal inferolateral wall in all) versus without LGE (7/22 vs 6/64, respectively, p = 0.01). Conclusions: In a large, unselected MVP sample inclusive of all arrhythmic presentations and leaflet subtypes, the prevalence of IBTWs is overall low and similar in those with and without ventricular arrhythmia, including SCA/SCD. In those with IBTWs, LGE in the papillary muscles or basal inferolateral wall is common, suggesting focal myocardial traction/fibrosis as the underlying anatomical substrate for repolarization abnormalities in the MVP population.

Abstract 13321: Identifying Mitral Valve Prolapse at Risk for Ventricular Arrhythmias and Myocardial Fibrosis From 12-lead ECGs Using Deep Learning

Background: Inferior biphasic or inverted T waves have been described on a standard 12-lead ECG in some, but not all patients with malignant mitral valve prolapse (MVP). In contrast, complex ventricular ectopy (ComVE) is associated with myocardial fibrosis and increased mortality in MVP and may represent a better marker of arrhythmic risk. We hypothesize that an ECG-based machine-learning model can identify MVP with ComVE and/or myocardial fibrosis on cardiac magnetic resonance (CMR) imaging within a large ECG database beyond traditional ECG criteria. Methods: A deep convolutional neural network (DNN) was trained to detect ComVE using 12 leads in 6,916 ECGs from 569 MVP patients evaluated at the University of California San Francisco (UCSF) between 2012 and 2020. A DNN was also trained using 87 UCSF MVP patients with available contrast CMR to detect late gadolinium enhancement (LGE). Results: The prevalence of ComVE was 160/569 or 28% (20 or 3% with cardiac arrest or sudden arrhythmic death). The area under the curve (AUC) of the DNN to detect ComVE was 0.81 (95% CI, 0.78-0.84) (Figure). AUC remained high even after excluding patients with moderate-severe mitral regurgitation (MR) [0.80 (95% CI, 0.77-0.83)], or with bileaflet MVP [0.81 (95% CI, 0.76-0.85)]. The top ECG segments able to discriminate ComVE vs no ComVE were related to ventricular depolarization and repolarization (early-mid ST and QRS fromV1, V3, and III). LGE in the papillary muscles or basal inferolateral wall was present in 22 of 87 (25%) with available CMR. The AUC for detection of LGE was 0.75 (95% CI, 0.68-0.82). Conclusions: A deep-learning model can detect MVP at risk for ventricular arrhythmias and fibrosis from standard 12-lead ECGs, and can identify novel ECG correlates of arrhythmic risk regardless of leaflet involvement or mitral regurgitation severity. ECG-based deep-learning may help select, within a large echocardiographic database, those MVP patients requiring closer follow-up and/or a CMR.

Deep artifact suppression for spiral real-time phase contrast cardiac magnetic resonance imaging in congenital heart disease

PurposeReal-time spiral phase contrast MR (PCMR) enables rapid free-breathing assessment of flow. Target spatial and temporal resolutions require high acceleration rates often leading to long reconstruction times. Here we propose a deep artifact suppression framework for fast and accurate flow quantification. MethodsU-Nets were trained for deep artifact suppression using 520 breath-hold gated spiral PCMR aortic datasets collected in congenital heart disease patients. Two spiral trajectories (uniform and perturbed) and two losses (Mean Absolute Error -MAE- and average structural similarity index measurement -SSIM-) were compared in synthetic data in terms of MAE, peak SNR (PSNR) and SSIM. Perturbed spiral PCMR was prospectively acquired in 20 patients. Stroke Volume (SV), peak mean velocity and edge sharpness measurements were compared to Compressed Sensing (CS) and Cartesian reference. ResultsIn synthetic data, perturbed spiral consistently outperformed uniform spiral for the different image metrics. U-Net MAE showed better MAE and PSNR while U-Net SSIM showed higher SSIM based metrics.In-vivo, there were no significant differences in SV between any of the real-time reconstructions and the reference standard Cartesian data. However, U-Net SSIM had better image sharpness and lower biases for peak velocity when compared to U-Net MAE. Reconstruction of 96 frames took ~59 s for CS and 3.9 s for U-Nets. ConclusionDeep artifact suppression of complex valued images using an SSIM based loss was successfully demonstrated in a cohort of congenital heart disease patients for fast and accurate flow quantification.

Regional Replacement and Diffuse Interstitial Fibrosis in Aortic Regurgitation: Prognostic Implications From Cardiac Magnetic Resonance

ObjectivesThis study used cardiac magnetic resonance (CMR) to assess left ventricular (LV) remodeling in chronic aortic regurgitation (AR) to identify both forms of myocardial fibrosis and examine its association with clinical outcomes. BackgroundChronic AR leads to LV remodeling, which is associated with 2 forms of myocardial fibrosis: regional replacement fibrosis that is directly imaged by late gadolinium enhancement (LGE) CMR; and diffuse interstitial fibrosis, which can be inferred by T1 mapping techniques. MethodsPatients with chronic AR who were undergoing contrast CMR with T1 mapping for valve assessment from 2011 to 2018 were enrolled. Patients with a confounding etiology of myocardial fibrosis were excluded. In addition to quantification of AR severity and LV volumetrics, LGE and T1 mapping pre- and post-contrast were performed to measure extracellular volume (ECV) and indexed ECV (iECV). Patients were followed up longitudinally to assess for the composite event of death and the need for aortic valve replacement. ResultsA total of 177 patients with isolated chronic AR were included (66% males, median age 58 years [IQR: 47.0-68.0 years]) with a median follow up of 2.5 years (IQR: 1.07-3.56 years). The iECV significantly increased with AR severity (P < 0.001), whereas ECV and replacement fibrosis did not (P = NS). On multivariate analysis, iECV remained associated with the composite event (P = 0.01). On Kaplan-Meier analysis stratified by AR regurgitant fraction (RF) and iECV, patients with AR RF severity ≥30% and iECV ≥24 mL/m2 demonstrated the highest event rate. ConclusionsAmong CMR biomarkers of fibrosis, iECV was more closely associated than replacement fibrosis or ECV with survival free of aortic valve replacement.

4D Flow analysis of intracavitary blood flow dynamics and energetics in the systemic right ventricle

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Italian Ministry of Health Background The systemic position of a morphologically right ventricle (SRV) makes it vulnerable to fail, leading to high incidence of heart failure and cardiac death [1]. Understanding SRV intracavitary blood flow dynamics and energetics could improve patient risk stratification. Purpose Testing the potential of three-dimensional time-resolved phase contrast cardiac magnetic resonance (4D Flow) in quantifying SRV blood flow dynamics and energetics. Methods 4D Flow prototype sequences were acquired on 3 patients (1 male, 2 females) with SRV in D-loop transposition of great arteries after atrial switch operation (D-TGA/ASO), 3 male patients with SRV in L-loop TGA (L-TGA) and healthy controls (2 males, 1 female). Kinetic energy (KE), viscous energy loss (EL), dissipation index (DI) calculated as EL to KE ratio, and hemodynamics forces (HFs) resulting from pressure gradients, were computed for the D-TGA/ASO and L-TGA SRVs, and for the control left ventricles (LVs) and right ventricles (RVs). HFs were decomposed in inferior-anterior, septal-lateral and basal-apical components (HFIA, HFSL, HFBA, respectively) Results Figure 1 reports the time-course of HF components and the general features of the enrolled subjects. In systole, all SRVs (Figure 1a-1b) presented a dominant HFIA and a minor HFSL, similarly to RVs (Figure 1c); however, HFSL had a positive peak, indicating septal contraction towards the SRV cavity, opposite to its normal motion. HFBA magnitude was similar to LVs (Figure 1d), suggesting that the shortening of the tricuspid anulus towards the apex is more pronounced than in RVs (Figure 1c). Over the whole cardiac cycle, DI values were highest in D-TGA/ASO SVRs (0.40-0.55); in L-TGA SRVs, DI values (0.24-0.45) were comparable to healthy LVs (0.22-0.37) and RVs (0.23-0.36). This difference may be related to the fact that in DTGA/ASO the left atrium is functionally replaced by a pulmonary venous baffle, which lacks efficient contraction, as highlighted by the absence of a distinctive A-wave in the KE time-course (Figure 2a). Due to the adaptation to systemic afterload, SRVs were hypertrophic (Figure 1a-1b), with indexed mass higher than normal RVs (Figure 1c), and presented reduced compliance to the diastolic filling, as suggested by increased KE E-wave slope in L-TGA (Figure 2b) compared to controls (Figure 2c-2d). Conclusions Intracavitary HFs in SRVs reveal a partial shift from a RV towards LV pattern. This occurs at the expenses of a higher energetic consumption in D-TGA/ASO than L-TGA, enlightening the crucial role of atrial contribution to impaired SRV diastolic filling. These findings corroborate the previous evidence that patients with D-TGA/ASO have abnormal decrease in stroke volume during exercise whereas L-TGA patients can reach values comparably to healthy controls [2].

Right atrium and cryptogenic ischaemic stroke in the young: a case–control study

BackgroundRecent studies suggest left atrial (LA) dysfunction in cryptogenic stroke. We studied the dynamics of right atrium (RA) and right atrial appendage (RAA) in young adults with cryptogenic stroke. We...

Prognostic value of depressed cardiac index after STEMI: a phase-contrast magnetic resonance study

Abstract Funding Acknowledgements Type of funding sources: None. Aims An invasively measured Cardiac Index (CI) of ≤2.2 l/min/m² is one of the strongest prognostic indicators after ST-elevation myocardial infarction, however knowledge is mainly based on invasive evaluations performed in the pre-stent era. Velocity-encoded Phase Contrast Cardiac Magnetic Resonance (PC-CMR) allows non-invasive determination of CI. Methods In this prospective study CMR was performed in 406 stable and contemporarily revascularized patients a median of 3 days after STEMI. Forward stroke volume was assessed at the level of the ascending aorta by PC-CMR. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were determined by cine CMR. Major adverse cardiac events (MACE) were defined as the composite of death, myocardial infarction or hospitalization for heart failure. Results Median CI was 2.52 l/min/m², 27% of patients had ≤2.2 l/min/m². Median LVEF was 53%, median GLS was -12.2%. During a median follow-up of 13.6 (12.1;62.9) months, 38 patients (8.7%) experienced a MACE. A depressed CI was significantly associated with MACE after adjustment for GLS and LVEF (HR = 2.55 (95%CI 1.10—5.28); p = 0.01), markers of myocardial injury (HR = 2.18, 95%CI 1.10-4.30, p = 0.02) and clinical parameters (HR = 2.42, 95%CI 1.19-4.90, p = 0.01). Adding CI to a model including LVEF and GLS led to significant discrimination improvement (0.55 [95%CI 0.18 - 0.91]; p = 0.003). Conclusions A CI of 2.2 l/min/m² or less as measured by PC-CMR was present in 27% of clinically stable patients after STEMI, which strongly and independently predicted medium-term MACE. The prognostic value of a depressed CI was superior and incremental to LVEF and GLS. Abstract Figure. Graphical Abstract