Ventricular Insertion Point Research Articles

Subclinical myocardial fibrosis is almost ubiquitous in the hearts of older British persons: 'MyoFit46' cardiovascular sub-study of the NSHD

Abstract Background Unprecedented numbers are now surviving to older age, but little is known about the burden or pattern of myocardial fibrosis in the asymptomatic elderly population. Previous 1.5 Tesla (T) cardiovascular magnetic resonance (CMR) studies found a prevalence of unexpected infarct-pattern late gadolinium enhancement (LGE) of 17-20% above 75 years but less is known about non-infarct pattern scar in this group. We investigated the prevalence, patterns, and clinical predictors of left ventricular (LV) scar in a large asymptomatic older age cohort. Methods CMR with a single 3T magnet was performed on participants all born in the same week in March 1946, as part of the longest running continued surveillance birth cohort: the National Survey of Health and Development. LV short-axis stack LGE imaging was performed using a free-breathing motion-corrected balanced steady-state free precession sequence with phase-sensitive inversion-recovery. Two blinded observers independently recorded the prevalence, extent, and pattern of LGE per participant. Logistic regression was used to study the association between clinicodemographic parameters and LGE. Results 460 participants were prospectively recruited of which 406 completed CMR with LGE imaging (77.8 ± 0.1 years, 44% male). 341 (84%) demonstrated LGE affecting a mean of 2.1±1.2 myocardial segments per participant (Figure 1). The commonest pattern of LGE was inferior right ventricular insertion point (RVIP), observed in 66.9%. Other patterns included (Figure 2): Linear mid-wall (19.6%) of which 38% were located in the inferior/lateral walls; subepicardial (12.1%); subendocardial infarct-pattern (8.8%); patchy/diffuse (1.6%); embolic LGE (0.6%). Sub-analysis was performed comparing those without significant unexpected fibrosis (LGE–) vs those with focal fibrosis (LGE+, excluding RVIP and those participants with a known history of prior myocardial infarction). LGE+ participants were more likely to be female (71.7% vs 49.1%, p<0.001) or diabetic (11.3% vs 5.1%, p=0.05), had a higher body surface area (BSA, 1.9 vs 1.8 m2, p<0.001), weight (80.1 vs 72.8 kg, p<0.001), LV indexed end systolic volume (24.2 vs 20.4 ml/m2, p=0.001) and LV indexed mass (59.2 vs 55.4 g/m2, p<0.001), and a lower LV ejection fraction (67.9 vs 71.8%, p<0.001) In multivariable logistic regression: BSA, LV indexed mass, LV ejection fraction and diabetic status were independently associated with LGE+ status (odds ratios [95% confidence intervals]: 9.4 [0.7–3.8]; 1.0 [0.01–0.05]; 0.9 [-0.08--0.02]; and 2.5 [0.03–1.7] respectively, p<0.05). Conclusion Advanced PSIR MOCO LGE imaging at 3T reveals that the majority (84%) of asymptomatic British persons above the age of 75 harbour unexpected ‘subclinical’ focal fibrosis, with a substantial proportion of these scars consistent with probable historical myocarditis events. Further work will now explore the life-course determinants of this scar burden in the older age human heart.

The Importance of Cardiac Magnetic Resonance in the Assessment Risk of Cardiac Arrhythmias in Patients with Arterial Hypertension.

Objectives: Arterial hypertension (AH) is one of the major risk factors for cardiovascular diseases. An association between untreated AH and arrhythmia is observed. Cardiac magnetic resonance (CMR) assesses myocardial fibrosis by detecting foci of late gadolinium enhancement (LGE). Clinical significance of LGE at the right ventricular insertion point (RVIP) is not fully established. This study aimed to assess the relationship between the presence of LGE at the RVIP determined by CMR and the incidence of arrhythmia in a group suffering from arterial hypertension. Methods: The study group consisted of 81 patients with AH (37 men and 44 women, age: 56.7 ± 7.1 years). All subjects underwent CMR and 24 h Holter ECG monitoring. Two subgroups were distinguished in the study group based on the criterion of the presence of LGE at the RVIP in CMR. The RVIP+ subgroup consisted of patients with LGE at the RVIP, while the RVIP- group consisted of patients without LGE at the RVIP. Results: The RVIP+ subgroup was characterized by higher maximum and minimum heart rates in 24 h Holter ECG recordings compared to the RVIP- subgroup (p < 0.05). The RVIP+ subgroup had a statistically significantly higher number of single premature supraventricular beats, supraventricular tachycardias, and single premature ventricular beats than the RVIP- subgroup (p < 0.05). Regression analysis documented that a longer duration of AH (counted from diagnosis) as well as the occurrence of LGE at the RVIP (assessed by CMR) are independent risk factors for arrhythmia (p < 0.05). Conclusions: Due to the possibility of detecting LGE at the RVIP, CMR may be a useful diagnostic method in estimating the risk of arrhythmias in the group of patients with AH.

Myocardial Fibrosis in Young and Veteran Athletes: Evidence from a Systematic Review of the Current Literature.

Background: Exercise is associated with several cardiac adaptations that can enhance one's cardiac output and allow one to sustain a higher level of oxygen demand for prolonged periods. However, adverse cardiac remodelling, such as myocardial fibrosis, has been identified in athletes engaging in long-term endurance exercise. Cardiac magnetic resonance (CMR) imaging is considered the noninvasive gold standard for its detection and quantification. This review seeks to highlight factors that contribute to the development of myocardial fibrosis in athletes and provide insights into the assessment and interpretation of myocardial fibrosis in athletes. Methods: A literature search was performed using the PubMed/Medline database and Google Scholar for publications that assessed myocardial fibrosis in athletes using CMR. Results: A total of 21 studies involving 1642 endurance athletes were included in the analysis, and myocardial fibrosis was found in 378 of 1595 athletes. A higher prevalence was seen in athletes with cardiac remodelling compared to control subjects (23.7 vs. 3.3%, p < 0.001). Similarly, we found that young endurance athletes had a significantly higher prevalence than veteran athletes (27.7 vs. 19.9%, p < 0.001), while male and female athletes were similar (19.7 vs. 16.4%, p = 0.207). Major myocardial fibrosis (nonischaemic and ischaemic patterns) was predominately observed in veteran athletes, particularly in males and infrequently in young athletes. The right ventricular insertion point was the most common fibrosis location, occurring in the majority of female (96%) and young athletes (84%). Myocardial native T1 values were significantly lower in athletes at 1.5 T (p < 0.001) and 3 T (p = 0.004), although they had similar extracellular volume values to those of control groups. Conclusions: The development of myocardial fibrosis in athletes appears to be a multifactorial process, with genetics, hormones, the exercise dose, and an adverse cardiovascular risk profile playing key roles. Major myocardial fibrosis is not a benign finding and warrants a comprehensive evaluation and follow-up regarding potential cardiac disease.

What is the meaning of late gadolinium enhancement at right ventricular insertion points in pulmonary arterial hypertension?

What is the meaning of late gadolinium enhancement at right ventricular insertion points in pulmonary arterial hypertension?

Advanced Myocardial MRI Tissue Characterization Combining Contrast Agent‐Free T1‐Rho Mapping With Fully Automated Analysis

BackgroundMyocardial T1‐rho (T1ρ) mapping is a promising method for identifying and quantifying myocardial injuries without contrast agents, but its clinical use is hindered by the lack of dedicated analysis tools.PurposeTo explore the feasibility of clinically integrated artificial intelligence‐driven analysis for efficient and automated myocardial T1ρ mapping.Study TypeRetrospective.PopulationFive hundred seventy‐three patients divided into a training (N = 500) and a test set (N = 73) including ischemic and nonischemic cases.Field Strength/SequenceSingle‐shot bSSFP T1ρ mapping sequence at 1.5 T.AssessmentThe automated process included: left ventricular (LV) wall segmentation, right ventricular insertion point detection and creation of a 16‐segment model for segmental T1ρ value analysis. Two radiologists (20 and 7 years of MRI experience) provided ground truth annotations. Interobserver variability and segmentation quality were assessed using the Dice coefficient with manual segmentation as reference standard. Global and segmental T1ρ values were compared. Processing times were measured.Statistical TestsIntraclass correlation coefficients (ICCs) and Bland–Altman analysis (bias ±2SD); Paired Student's t‐tests and one‐way ANOVA. A P value &lt;0.05 was considered significant.ResultsThe automated approach significantly reduced processing time (3 seconds vs. 1 minute 51 seconds ± 22 seconds). In the test set, automated LV wall segmentation closely matched manual results (Dice 81.9% ± 9.0) and closely aligned with interobserver segmentation (Dice 82.2% ± 6.5). Excellent ICCs were achieved on a patient basis (0.94 [95% CI: 0.91 to 0.96]) with bias of −0.93 cm2 ± 6.60. There was no significant difference in global T1ρ values between manual (54.9 msec ± 4.6; 95% CI: 53.8 to 56.0 msec, range: 46.6–70.9 msec) and automated processing (55.4 msec ± 5.1; 95% CI: 54.2 to 56.6 msec; range: 46.4–75.1 msec; P = 0.099). The pipeline demonstrated a high level of agreement with manual‐derived T1ρ values at the patient level (ICC = 0.85; bias +0.52 msec ± 5.18). No significant differences in myocardial T1ρ values were found between methods across the 16 segments (P = 0.75).Data ConclusionAutomated myocardial T1ρ mapping shows promise for the rapid and noninvasive assessment of heart disease.Evidence Level3Technical EfficacyStage 1

THE IMPORTANCE OF CARDIAC MAGNETIC RESONANCE IMAGING IN THE ASSESSMENT OF THE RISK OF CARDIAC ARRHYTHMIAS IN PATIENTS WITH ARTERIAL HYPERTENSION

Objective: Arterial hypertension leads to organ changes, including left ventricular hypertrophy. The increased mass of left ventricle increases the risk of cardiac arrhythmias, which enhances the risk of sudden cardiac death. Cardiac magnetic resonance imaging (CMRI) can identify the presence of myocardial fibrosis by assessing late gadolinium enhancement (LGE). The aim of the study was to assess the relationship between the presence of late gadolinium enhancement at the right ventricular insertion point (RVIP) determined by CMRI and the occurrence of cardiac arrhythmias in patients with arterial hypertension. Design and method: 30 patients with essential hypertension were qualified for the study, 18 men and 12 women, the average age of the subjects was 55.5 ± 12.4 years. All subjects underwent cardiac magnetic resonance imaging and 24-hour Holter ECG monitoring. Based on the presence of LGE at the right ventricular insertion point, assessed by CMRI, the subjects were divided into two subgroups. The first subgroup consisted of subjects with LGE at the right ventricular insertion point (RVIP + subgroup), while the second subgroup consisted of subjects without LGE at the right ventricular insertion point (RVIP - subgroup). Results: Subjects with LGE at the right ventricular insertion point were characterized by higher maximum and minimum heart rates in 24-hour Holter ECG recordings compared to subjects without LGE at the right ventricular insertion point (p &lt; 0.05). In subjects with LGE at the right ventricular insertion point, Holter ECG evaluation revealed a statistically significantly higher number of single premature supraventricular beats, single premature ventricular beats and supraventricular tachycardias compared to subjects without LGE at the right ventricular insertion point (p &lt; 0.05). The regression analysis performed showed that a longer time from the diagnosis of hypertension and the occurrence of LGE at the right ventricular insertion point assessed using CMRI are independent risk factors for cardiac arrhythmias (p &lt; 0.05). Conclusions: Cardiac magnetic resonance imaging by identifying of late gadolinium enhancement at the right ventricular insertion point may be a useful diagnostic method in assessing the risk of cardiac arrhythmias in a group of patients with arterial hypertension.

The role of cardiac magnetic resonance in sports cardiology: results from a large cohort of athletes.

Cardiac magnetic resonance (CMR) provides information on morpho-functional abnormalities and myocardial tissue characterisation. Appropriate indications for CMR in athletes are uncertain. To analyse the CMR performed at our Institute to evaluate variables associated with pathologic findings in a large cohort of athletes presenting with different clinical conditions. All the CMR performed at our Institute in athletes aged > 14years were recruited. CMR indications were investigated. CMR was categorised as "positive" or "negative" based on the presence of morphological and/or functional abnormalities and/or the presence of late gadolinium enhancement (excluding the right ventricular insertion point), fat infiltration, or oedema. Variables associated with "positive" CMR were explored. A total of 503 CMR were included in the analysis. "Negative" and "positive" CMR were 61% and 39%, respectively. Uncommon ventricular arrhythmias (VAs) were the most frequent indications for CMR, but the proportion of positive results was low (37%), and only polymorphic ventricular patterns were associated with positive CMR (p = 0.006). T-wave inversion at 12-lead ECG, particularly on lateral and inferolateral leads, was associated with positive CMR in 34% of athletes (p = 0.05). Echocardiography abnormalities resulted in a large proportion (58%) of positive CMR, mostly cardiomyopathies. CMR is more efficient in identifying a pathologic cardiac substrate in athletes in case of VAs (i.e., polymorphic beats), abnormal ECG repolarisation (negative T-waves in inferolateral leads), and borderline echocardiographic findings (LV hypertrophy, mildly depressed LV function). On the other hand, CMR is associated with a large proportion of negative results. Therefore, a careful clinical selection is needed to indicate CMR in athletes appropriately.

Myocardial involvement characteristics by cardiac MR imaging in neurological and non-neurological Wilson disease patients

ObjectivesTo explore the characteristics of myocardial involvement in Wilson Disease (WD) patients by cardiac magnetic resonance (CMR).MethodsWe prospectively included WD patients and age- and sex-matched healthy population. We applied CMR to analyze cardiac function, strain, T1 maps, T2 maps, extracellular volume fraction (ECV) maps, and LGE images. Subgroup analyzes were performed for patients with WD with predominantly neurologic manifestations (WD‐neuro +) or only hepatic manifestations (WD‐neuro −).ResultsForty-one WD patients (age 27.9 ± 8.0 years) and 40 healthy controls (age 25.4 ± 2.9 years) were included in this study. Compared to controls, the T1, T2, and ECV values were significantly increased in the WD group (T1 1085.1 ± 39.1 vs. 1046.5 ± 33.1 ms, T2 54.2 ± 3.3 ms vs. 51.5 ± 2.6 ms, ECV 31.8 ± 3.6% vs. 24.3 ± 3.7%) (all p < 0.001). LGE analysis revealed that LGE in WD patients was predominantly localized to the right ventricular insertion point and interventricular septum. Furthermore, the WD‐neuro + group showed more severe myocardial damage compared to WD‐neuro − group. The Unified Wilson Disease Rating Scale score was significantly correlated with ECV (Pearson’s r = 0.64, p < 0.001).ConclusionsCMR could detect early myocardial involvement in WD patients without overt cardiac function dysfunction. Furthermore, characteristics of myocardial involvement were different between WD‐neuro + and WD‐neuro − , and myocardial involvement might be more severe in WD‐neuro + patients.Critical relevance statementCardiac magnetic resonance enables early detection of myocardial involvement in Wilson disease patients, contributing to the understanding of distinct myocardial characteristics in different subgroups and potentially aiding in the assessment of disease severity.Key points• CMR detects WD myocardial involvement with increased T1, T2, ECV.• WD‐neuro + patients show more severe myocardial damage and correlation with ECV.• Differences of myocardial characteristics exist between WD‐neuro + and WD‐neuro − patients.Graphical

Right ventricular fibrosis in adults with uncorrected secundum atrial septal defect and pulmonary hypertension: a cardiovascular magnetic resonance study with late gadolinium enhancement, native T1 and extracellular volume.

Right ventricular (RV) fibrosis represents both adaptive and maladaptive responses to the overloaded RV condition. Its role in pulmonary hypertension (PH) associated with secundum atrial septal defect (ASD), which is the most common adult congenital heart disease (CHD), remains poorly understood. We enrolled 65 participants aged ≥18 years old with uncorrected secundum ASD who had undergone clinically indicated right heart catheterization (RHC), divided into the non-PH group (n = 7), PH group (n = 42), and Eisenmenger syndrome (ES) group (n = 16). We conducted cardiovascular magnetic resonance (CMR) studies with late gadolinium enhancement (LGE) imaging, native T1 mapping, and extracellular volume (ECV) measurement to evaluate the extent and clinical correlates of RV fibrosis. LGE was present in 94% of the population and 86% of the non-PH group, mostly located at the right ventricular insertion point (RVIP) regions. LGE in the septal and inferior RV region was predominantly observed in the ES group compared to the other groups (p = 0.031 and p < 0.001, respectively). The mean LGE scores in the ES and PH groups were significantly higher than those in the non-PH group (3.38 ± 0.96 vs. 2.74 ± 1.04 vs. 1.57 ± 0.79; p = 0.001). The ES and PH groups had significantly higher degrees of interstitial RV fibrosis compared to those in the non-PH group, indicated by native T1 (1,199.9 ± 68.9 ms vs. 1,131.4 ± 47.8 ms vs. 1,105.4 ± 44.0 ms; p < 0.001) and ECV (43.6 ± 6.6% vs. 39.5 ± 4.9% vs. 39.4 ± 5.8%; p = 0.037). Additionally, native T1 significantly correlated with pulmonary vascular resistance (r = 0.708, p < 0.001), RV ejection fraction (r = -0.468, p < 0.001) and peripheral oxygen saturation (r = -0.410, p = 0.001). In patients with uncorrected secundum ASD, RV fibrosis may occur before the development of PH and progressively intensify alongside the progression of PH severity. A higher degree of RV fibrosis, derived from CMR imaging, correlates with worse hemodynamics, RV dysfunction, and poorer clinical conditions.

Deep learning for classification of late gadolinium enhancement lesions based on the 16-segment left ventricular model

PurposeThis study aimed to develop and validate a deep learning-based method that allows for segmental analysis of myocardial late gadolinium enhancement (LGE) lesions. MethodsCardiac LGE data from 170 patients with coronary artery disease and non-ischemic heart disease were used for training, validation, and testing. Short-axis images were transformed to polar space after identification of the left ventricular (LV) center point and anterior right ventricular (RV) insertion point. Images were obtained after dividing the polar transformed images into segments based on the 16-segment LV model. Five different deep convolutional neural network (CNN) models were developed and validated using the labeled data, where the image after the division corresponded to a segment, and the lesion labeling was based on the 16-segment LV model. Unseen testing data were used to evaluate the performance of the lesion classification. ResultsWithout manual lesion segmentation and annotation, the proposed method showed an area under the curve (AUC) of 0.875, and a precision, recall, and F1-score of 0.723, 0.783, and 0.752, respectively for the lesion class when the pretrained ResNet50 model was tested for all slice images. The two pretrained models of ResNet50 and EfficientNet-B0 outperformed the three non-pretrained CNN models in terms of AUCs (0.873–0.875 vs. 0.834–0.841). ConclusionThe proposed method is based on learning a deep CNN model from polar transformed images to predict LGE lesions with good accuracy and does not require time-consuming annotation procedures such as lesion segmentation.

Late gadolinium enhancement distribution patterns in non-ischaemic dilated cardiomyopathy: genotype-phenotype correlation.

Late gadolinium enhancement (LGE) is frequently found in patients with dilated cardiomyopathy (DCM); there is little information about its frequency and distribution pattern according to the underlying genetic substrate. We sought to describe LGE patterns according to genotypes and to analyse the risk of major ventricular arrhythmias (MVA) according to patterns. Cardiac magnetic resonance findings and LGE distribution according to genetics were performed in a cohort of 600 DCM patients followed at 20 Spanish centres. After exclusion of individuals with multiple causative gene variants or with variants in infrequent DCM-causing genes, 577 patients (34% females, mean age 53.5 years, left ventricular ejection fraction 36.9 ± 13.9%) conformed to the final cohort. A causative genetic variant was identified in 219 (38%) patients, and 147 (25.5%) had LGE. Significant differences were found comparing LGE patterns between genes (P < 0.001). LGE was absent or rare in patients with variants in TNNT2, RBM20, and MYH7 (0, 5, and 20%, respectively). Patients with variants in DMD, DSP, and FLNC showed a predominance of LGE subepicardial patterns (50, 41, and 18%, respectively), whereas patients with variants in TTN, BAG3, LMNA, and MYBPC3 showed unspecific LGE patterns. The genetic yield differed according to LGE patterns. Patients with subepicardial, lineal midwall, transmural, and right ventricular insertion points or with combinations of LGE patterns showed an increased risk of MVA compared with patients without LGE. LGE patterns in DCM have a specific distribution according to the affected gene. Certain LGE patterns are associated with an increased risk of MVA and with an increased yield of genetic testing.

Cardiac structure discontinuities revealed by ex-vivo microstructural characterization. A focus on the basal inferoseptal left ventricle region

BackgroundWhile the microstructure of the left ventricle (LV) has been largely described, only a few studies investigated the right ventricular insertion point (RVIP). It was accepted that the aggregate cardiomyocytes organization was much more complex due to the intersection of the ventricular cavities but a precise structural characterization in the human heart was lacking even if clinical phenotypes related to right ventricular wall stress or arrhythmia were observed in this region. MethodsMRI-derived anatomical imaging (150 µm3) and diffusion tensor imaging (600 µm3) were performed in large mammalian whole hearts (human: N = 5, sheep: N = 5). Fractional anisotropy, aggregate cardiomyocytes orientations and tractography were compared within both species. Aggregate cardiomyocytes orientation on one ex-vivo sheep whole heart was then computed using structure tensor imaging (STI) from 21 µm isotropic acquisition acquired with micro computed tomography (MicroCT) imaging. Macroscopic and histological examination were performed. Lastly, experimental cardiomyocytes orientation distribution was then compared to the usual rule-based model using electrophysiological (EP) modeling. Electrical activity was modeled with the monodomain formulation. ResultsThe RVIP at the level of the inferior ventricular septum presented a unique arrangement of aggregate cardiomyocytes. An abrupt, mid-myocardial change in cardiomyocytes orientation was observed, delimiting a triangle-shaped region, present in both sheep and human hearts. FA's histogram distribution (mean ± std: 0.29 ± 0.06) of the identified region as well as the main dimension (22.2 mm ± 5.6 mm) was found homogeneous across samples and species. Averaged volume is 0.34 cm3 ± 0.15 cm3. Both local activation time (LAT) and morphology of pseudo-ECGs were strongly impacted with delayed LAT and change in peak-to-peak amplitude in the simulated wedge model. ConclusionThe study was the first to describe the 3D cardiomyocytes architecture of the basal inferoseptal left ventricle region in human hearts and identify the presence of a well-organized aggregate cardiomyocytes arrangement and cardiac structural discontinuities. The results might offer a better appreciation of clinical phenotypes like RVIP-late gadolinium enhancement or uncommon idiopathic ventricular arrhythmias (VA) originating from this region.

Not Just a One-Way: Mahaim Accessory Pathway Concomitantly Supporting Orthodromic Atrioventricular Re-Entrant Tachycardia

We report the case of a 41-year-old female with documented narrow QRS tachycardia. During electrophysiological study, both orthodromic and antidromic atrioventricular reentry tachycardia (AVRT) were demonstrated as well as short episodes of pre-excited atrial fibrillation. Programmed atrial stimulation resulted in decremental anterograde conduction on the AP, thus confirming an unexpected Mahaim accessory pathway (AP) diagnosis. Limited 3D activation maps of the right atrium during orthoAVRT, respectively, and the right ventricle (RV) during antiAVRT were constructed and helped accurately describe the atrial and ventricular insertion points, which were superposed on the tricuspid ring, confirming the existence of a single short atrio-ventricular right free wall AP. Short atrioventricular APs with anterograde Mahaim-type conduction concomitantly sustaining orthodromic AVRT are extremely rare. Electroanatomical 3D mapping may help both to clarify the diagnosis and increase the success rate by accurately describing the insertion points of complex accessory pathways.

Hypertrophic cardiomyopathy and left ventricular non-compaction cardiomyopathy: two in one.

A 22-year-old asymptomatic Caucasian woman was referred because of an elevated NT-pro-BNP level (1225 ng/L, normal <125 ng/L) and a positive family history of unclear cardiomyopathy. Her electrocardiogram showed sinus rhythm, left axis deviation with signs of left ventricular (LV) hypertrophy, and repolarization abnormalities (Panel A). The transthoracic echocardiography revealed an asymmetrical LV hypertrophy without signs of left ventricular outflow tract obstruction at rest or under provocative Valsalva manoeuvre (Supplementary material online, Video S1). Imaging with cardiovascular magnetic resonance (CMR) confirmed asymmetrical LV hypertrophy with a maximum wall thickness of 18 mm. CMR also showed biventricular prominent trabeculation with multiple anterior, septal and inferior deep recesses (Panel B, Supplementary material online, Video S2) and a maximum ratio of non-compacted to compacted myocardium of 2.6 (Supplementary material online, Image). Biventricular volumes and global ejection fraction were normal with a mild hypokinesia of the hypertrophied LV segments. Late Gadolinium Enhancement and post-contrast T1 mapping demonstrated focal patchy fibrosis in the hypertrophied segments and at both right ventricular insertion points (Panel C, D).

The application value of cardiac magnetic resonance quantitative T1 mapping technique for risk stratification in patients with pulmonary arterial hypertension

Objective: To explore the application value of cardiac magnetic resonance (CMR) native T1 mapping for risk stratification in patients with pulmonary arterial hypertension (PAH). Methods: A total of 59 patients with diagnosed PAH and clear-documented risk status in Peking Union Medical College Hospital and underwent CMR examination between January 2019 and December 2021 were retrospectively included, which including 12 males and 47 females, aged from 4 to 77 (31±13) years. Those patients were subdivided into two groups based on the clinically-assessed risk status: low-risk group (n=30) and intermediate-/high-risk group (n=29). Twenty-five healthy individuals were included as controls. Base, midventricular, and apical inferior right ventricular insertion point (IRVIP) native T1 values on short axis images were measured. Native T1 values in PAH patients and control group, in low-risk group and intermediate-/high-risk group were compared, respectively, and receiver operating characteristics (ROC) curves with area under the curves (AUC) were calculated to evaluate the application value of native T1 values for risk stratification in PAH patients. Results: Base, midventricular and apical IRVIP native T1 of PAH patients were all significantly increased as compared to controls [Base:(1 439.31±129.96) vs (1 282.36±37.18) ms;midventricular:(1 450.32±111.55) vs (1 287.56±53.16) ms;apical:(1 444.12±109.15) vs (1 266.36±75.31) ms](all P<0.001). The midventricular IRVIP native T1 values were significantly higher in patients in intermediate-/high-risk status as compared to those in low-risk status [ (1 493.24±126.32) vs (1 428.50±85.73) ms,P=0.026]. The AUC of mid ventricle IRVIP native T1 for distinguishing patients in intermediate-/high-risk status was 0.741. The base [(1 458.21±134.96) vs (1 421.03±104.75) ms, P=0.241] and apical [(1 465.90±125.36) vs (1 423.07±87.87) ms,P=0.136] IRVIP native T1 values in patients in intermediate-/high-risk group were also numerically higher as compared with patients in low-risk status, however, without statistical significant (both P>0.05). Conclusion: Midventricular IRVIP native T1 value might have a role for assisting in risk stratification in PAH patients, which was clinically significant for facilitating the work-up and prognosis improvement of PAH patients.

Myocardial extracellular volume quantification by cardiac CT in pulmonary hypertension: Comparison with cardiac MRI

PurposeMyocardial extracellular volume (ECV) measured by cardiac magnetic resonance imaging (MRI) has been suggested as a marker of disease severity in pulmonary hypertension (PH). However, consistency between ECVs quantified by computed tomography (CT) and MRI has not been sufficiently investigated in (PH). We investigated the utility of CT-ECV in PH, using MRI-ECV as a reference standard. MethodWe evaluated 20 patients with known or suspected PH who underwent dual-energy CT, cardiac MRI, and right heart catheterization. We used Pearson correlation analysis to investigate correlations between CT-ECV and MRI-ECV. We also assessed correlations between ECV and mean pulmonary artery pressure (mPAP). ResultsCT-ECV showed a very strong correlation with MRI-ECV at the anterior (r = 0.83) and posterior right ventricular insertion points (RVIPs) (r = 0.84). CT-ECV and MRI-ECV were strongly correlated in the septum and left ventricular free wall (r = 0.79–0.73) but weakly correlated in the right ventricular free wall (r = 0.26). CT-ECV showed a strong correlation with mPAP in the anterior RVIP (r = 0.64) and a moderate correlation in the posterior RVIP and septum (r = 0.50–0.42). Compared with CT-ECV, MRI-ECV had a higher correlation with mPAP; however, the difference was not significant (anterior RVIP, r = 0.72 [MRI-ECV] vs. 0.64 [CT-ECV], p = 0.663; posterior RVIP, r = 0.67 vs. 0.50, p = 0.446). ConclusionDual-energy CT can quantify myocardial ECV and yield results comparable to those obtained using cardiac MRI. CT-ECV in the anterior RVIP could be a noninvasive surrogate marker of disease severity in PH.

Deep Learning Analysis of Cardiac MRI in Legacy Datasets: Multi-Ethnic Study of Atherosclerosis.

The Multi-Ethnic Study of Atherosclerosis (MESA), begun in 2000, was the first large cohort study to incorporate cardiovascular magnetic resonance (CMR) to study the mechanisms of cardiovascular disease in over 5,000 initially asymptomatic participants, and there is now a wealth of follow-up data over 20 years. However, the imaging technology used to generate the CMR images is no longer in routine use, and methods trained on modern data fail when applied to such legacy datasets. This study aimed to develop a fully automated CMR analysis pipeline that leverages the ability of machine learning algorithms to enable extraction of additional information from such a large-scale legacy dataset, expanding on the original manual analyses. We combined the original study analyses with new annotations to develop a set of automated methods for customizing 3D left ventricular (LV) shape models to each CMR exam and build a statistical shape atlas. We trained VGGNet convolutional neural networks using a transfer learning sequence between two-chamber, four-chamber, and short-axis MRI views to detect landmarks. A U-Net architecture was used to detect the endocardial and epicardial boundaries in short-axis images. The landmark detection network accurately predicted mitral valve and right ventricular insertion points with average error distance <2.5 mm. The agreement of the network with two observers was excellent (intraclass correlation coefficient >0.9). The segmentation network produced average Dice score of 0.9 for both myocardium and LV cavity. Differences between the manual and automated analyses were small, i.e., <1.0 ± 2.6 mL/m2 for indexed LV volume, 3.0 ± 6.4 g/m2 for indexed LV mass, and 0.6 ± 3.3% for ejection fraction. In an independent atlas validation dataset, the LV atlas built from the fully automated pipeline showed similar statistical relationships to an atlas built from the manual analysis. Hence, the proposed pipeline is not only a promising framework to automatically assess additional measures of ventricular function, but also to study relationships between cardiac morphologies and future cardiac events, in a large-scale population study.

Detection and evaluation of myocardial fibrosis in Eisenmenger syndrome using cardiovascular magnetic resonance late gadolinium enhancement and T1 mapping

BackgroundMyocardial fibrosis is a common pathophysiological process involved in many cardiovascular diseases. However, limited prior studies suggested no association between focal myocardial fibrosis detected by cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) and disease severity in Eisenmenger syndrome (ES). This study aimed to explore potential associations between myocardial fibrosis evaluated by the CMR LGE and T1 mapping and risk stratification profiles including exercise tolerance, serum biomarkers, hemodynamics, and right ventricular (RV) function in these patients.MethodsForty-five adults with ES and 30 healthy subjects were included. All subjects underwent a contrast-enhanced 3T CMR. Focal replacement fibrosis was visualized on LGE images. The locations of LGE were recorded. After excluding LGE in ventricular insertion point (VIP), ES patients were divided into myocardial LGE-positive (LGE+) and LGE-negative (LGE−) subgroups. Regions of interest in the septal myocardium were manually contoured in the T1 mapping images to determine the diffuse myocardial fibrosis. The relationships between myocardial fibrosis and 6-min walk test (6MWT), N-terminal pro-brain natriuretic peptide (NT-pro BNP), hematocrit, mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance index (PVRI), RV/left ventricular end-systolic volume (RV/LV ESV), RV ejection fraction (RVEF), and risk stratification were analyzed.ResultsMyocardial LGE (excluding VIP) was common in ES (16/45, 35.6%), and often located in the septum (12/45, 26.7%). The clinical characteristics, hemodynamics, CMR morphology and function, and extracellular volume fraction (ECV) were similar in the LGE+ and LGE− groups (all P > 0.05). ECV was significantly higher in ES patients (28.6 ± 5.9% vs. 25.6 ± 2.2%, P < 0.05) and those with LGE− ES (28.3 ± 5.9% vs. 25.6 ± 2.2%, P < 0.05) than healthy controls. We found significant correlations between ECV and log NT-pro BNP, hematocrit, mPAP, PVRI, RV/LV ESV, and RVEF (all P < 0.05), and correlations trends between ECV and 6MWT (P = 0.06) in ES patients. An ECV threshold of 29.0% performed well in differentiating patients with high-risk ES from those with intermediate or low risk (area under curve 0.857, P < 0.001).ConclusionsMyocardial fibrosis is a common feature of ES. ECV may serve as an important imaging marker for ES disease severity.

Prognostic value of right ventricular native T1 mapping in pulmonary arterial hypertension.

BackgroundRight ventricular function is an important prognostic marker for pulmonary arterial hypertension. Native T1 mapping using cardiovascular magnetic resonance imaging can characterize the myocardium, but accumulating evidence indicates that T1 values of the septum or ventricular insertion points do not have predictive potential in pulmonary arterial hypertension. We aimed to elucidate whether native T1 values of the right ventricular free wall (RVT1) can predict poor outcomes in patients with pulmonary arterial hypertension.MethodsThis retrospective study included 30 patients with pulmonary arterial hypertension (median age, 45 years; mean pulmonary artery pressure, 41±13 mmHg) and 16 healthy controls (median age, 43 years) who underwent native T1 mapping. RVT1 was obtained from the inferior right ventricular free wall during end systole.ResultsPatients with pulmonary arterial hypertension had significantly higher native RVT1 than did controls (1384±74 vs. 1217±57 ms, p<0.001). Compared with T1 values of the septum or ventricular insertion points, RVT1 correlated better with the effective right ventricular elastance index (R = −0.53, p = 0.003), ventricular-arterial uncoupling (R = 0.46, p = 0.013), and serum brain natriuretic peptide levels (R = 0.65, p<0.001). Moreover, the baseline RVT1 was an accurate predictor of the reduced right ventricular ejection fraction at the 12-month follow-up (delta -3%). RVT1 was independently associated with composite events of death or hospitalization from any cause (hazard ratio = 1.02, p = 0.002).ConclusionsRVT1 was predictive of right ventricular performance and outcomes in patients with pulmonary arterial hypertension. Thus, native T1 mapping in the right ventricular free wall may be an effective prognostic method for pulmonary arterial hypertension.

Abstract 12567: Reduced Myocardial Strain is Associated With Myocardial Inflammation and Fibrosis on Cardiovascular Magnetic Resonance Imaging in Collegiate Athletes Recovering From SARS-CoV-2 Infection

Introduction: Myocarditis is an important cause of sudden cardiac death in competitive athletes. There have been reports of myocardial inflammation on cardiovascular magnetic resonance (CMR) in athlete and non-athlete populations after SARS-CoV-2 infection; however, their clinical and functional significance is not known. We sought to investigate the relationship between left ventricular (LV) strain and other CMR markers suggestive of myocardial inflammation or fibrosis. Hypothesis: Reduced myocardial strain is associated with the presence of CMR abnormalities suggestive of inflammation, fibrosis, or necrosis in athletes recovering from SARS-CoV-2 infection. Methods: Collegiate athletes (N = 123) underwent a comprehensive CMR exam including strain encoded (SENC) imaging. We analyzed LV global longitudinal strain (GLS) across five groups defined by the presence or absence of late gadolinium enhancement (LGE), and T1 or T2 abnormalities. Myocarditis diagnosis on CMR required both abnormal T1 or LGE, and abnormal T2, in the same LV segment. Results: We enrolled 11 COVID negative control athletes (Group 1). Among COVID positive athletes, 42 had no abnormalities on CMR (Group 2), 31 had isolated right ventricular insertion point (RVIP) LGE (Group 3), 28 had LGE beyond RVIP (Group 4), and 11 athletes had myocarditis (Group 5). GLS was significantly lower in Groups 3, 4, and 5 compared with negative controls (p&lt;0.05, Figure 1). There was a deterioration in GLS as CMR abnormalities progressed from control athletes to those with LGE and myocarditis. There was no significant difference in LV ejection fraction between the 5 groups. Conclusions: In conclusion, SARS-CoV-2 infection in collegiate athletes leads to subtle abnormalities in cardiac function detected by GLS that correlate with abnormal mapping and LGE suggestive of myocardial inflammation and fibrosis. The clinical significance of these abnormalities remains to be determined.