Cardiovascular Magnetic Resonance Late Gadolinium Research Articles

A pipeline for developing digital cardiac twins integrating cardiovascular magnetic resonance and electrocardiographic imaging: results from the MyoFit46 study

Abstract Background Personalised cardiovascular medicine uses multimodal screening and diagnostic tools, spanning from organ to tissue to molecular levels, to generate a complex and detailed patient phenotype. Cardiac digital twins are powerful tools capable of merging and explore these multimodal data by developing virtual, mechanistic and predictive versions of the patient's heart. State-of-the-art pipelines are mainly based on artificial intelligence and optimization process to replicate clinical data and not used it as an input. We present a proof-of-principle pipeline for building digital heart twins based on cardiovascular magnetic resonance (CMR) imaging and integrated electrocardiographic imaging (ECGI) for diverse clinical scenarios by integrating them into the model (Fig. 1). Methods CMR at 3T 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. Cine steady-state free precession end-diastolic frames provided anatomical information per participant while CMR multiparametric mapping and late gadolinium enhancement (LGE) provided tissue characteristics to the electrical myocardial model used in the finite element solver Alya. Lastly, the ECGI activation map was used as a source to define the intrinsic endocardial activation sequence by applying a case-specific correction based on wall thickness and myofibers orientation. Activation-repolarization intervals map was used to introduce the personalised repolarization heterogeneities. Results In total, 406 prospectively recruited participants (77.8 ± 0.1 years, 44% male) had multiparametric CMR with ECGI for digital twin reconstruction. The pipeline’s performance was evaluated by measuring the root mean square error (RMSE) between the ECGI activation and repolarization maps with the in-silico ones obtained without applying the proposed pipeline (Baseline) and after its application (ecgi2model). Results obtained using ecgi2model pipeline presented a significantly reduced activation and repolarization RMSE (Fig. 2b), even providing accurate results in patients with different LGE patterns (Fig. 2c). Conclusion Personalised virtual heart models can be constructed at scale using real-world myocardial structural, functional, and electrical properties, from advanced CMR and ECGI data. Proposed digital twins provide a framework for personalised arrhythmic risk assessment based on real clinical data and also its applicability for in-silico clinical trials. Fig.1 Digital twins pipeline. Fig.2 a) Flattened epicardial map. b) RMSE of activation (ACT), repolarization (RPL) and activation-repolarization intervals (ARI) for the different methods methods. c) ACT and RPL maps obtained from ECGI, baseline simulation and ecgi2model simulation in a healthy participant with normal myocardial tissue, another with subendocardial LGE, and another with subepicardial LGE.Figure 1Figure 2

Three-dimensional left ventricular strain analysis in Fabry disease: correlation with heart failure severity, myocardial scar and impact on long-term prognosis

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Charles University Research program “Cooperatio - Cardiovascular Science”. Introduction Fabry disease (FD) is a multisystemic lysosomal storage disorder caused by a defect in the gene coding the alpha-galactosidase A enzyme. Cardiac involvement typically manifests as a phenocopy of hypertrophic cardiomyopathy. Three-dimensional echocardiography can analyze myocardial deformation of the left ventricle (LV) in both circumferential and longitudinal dimensions. Purpose We assessed 3D echocardiographic strain of the LV in FD patients in relation to heart failure severity, the presence of cardiovascular magnetic resonance (CMR) scar and long-term prognosis. Methods 3D echocardiography was feasible in 75/99 FD patients. Baseline natriuretic peptides and CMR late gadolinium enhancement were assessed together with long term outcome (death, heart failure decompensation or cardiovascular hospitalization) over a median follow-up of 3.1 years. Results The average age was 47 ± 14 years, 44% of patients were male and 51% expressed hypertrophy or concentric remodeling of the LV. Average LV ejection fraction (EF) was 65 ± 6%. A stronger correlation was observed for NTproBNP levels with 3D global longitudinal strain (GLS) (r = 0.49, p < 0.0001) than with 3D global circumferential strain (GCS) (r = 0.38, p < 0.001). LV EF by 3D weakly correlated with NTproBNP levels (r = 0.25, p = 0.036). Individuals with posterolateral scar on CMR had significantly lower local 3D circumferential strain at corresponding region (p = 0.008). 3D GLS was associated with long-term outcome (adjusted HR 0.84, CI 0.75, 0.95, p = 0.004) while 3D GCS was not (HR 0.94, CI 0.85 – 1.10, p = 0.284). 3D LV EF was not associated with long-term outcome. Conclusion 3D GLS is strongly associated with both heart failure severity measured as natriuretic peptides levels and long-term prognosis. Only borderline association of 3D GCS with HF severity and no association with prognosis was observed. Decreased local 3D CS reflects typical posterolateral scarring in FD. Where feasible, 3D-strain echocardiography can be used for comprehensive mechanical assessment of the LV in FD patients.

Applying quantitative CMR parameters for detecting myocardial lesion in immune checkpoint inhibitors-associated myocarditis

PurposeSparse researches evaluated the quantitative cardiovascular magnetic resonance (CMR) parameters for immune checkpoint inhibitors (ICI)-associated myocarditis. We aimed to apply quantitative CMR mappings and late gadolinium enhancement (LGE) extent for detecting ICI-associated myocarditis. MethodThe retrospective study included patients with ICI-associated myocarditis and CMR examination from August 2018 to August 2021 in our hospital. ICI-associated myocarditis was clinically diagnosed based on the clinical criteria by European Society of Cardiology guidelines. The multiparametric CMR images including T2 mapping and black blood T2-weighted images were used to evaluate myocardial edema. The myocardial edema ratio (ER) ≥ 2.0 was applied for determining myocardial edema on T2-weighted images. Results56 patients with ICI-associated myocarditis were included. The global T2 value and native T1 value of patients with ICI-associated myocarditis were significantly higher than the reference ranges in our hospital (p < 0.05). The rate of elevated global T2 value (92%) was significantly higher than those of abnormal native T1 value (73%), ER (52%) and LGE presence (68%) in patients with ICI-associated myocarditis (p < 0.05). The LGE extent and left ventricular ejection fraction of patients with ICI-associated myocarditis were 10.38 ± 9.64% and 56.42 ± 8.54%, respectively. LGE extent inversely correlated with left ventricular ejection fraction (r = -0.38, p = 0.004) but positively correlated with native T1 value (r = 0.28, p < 0.04) and extracellular volume (r = 0.50, p = 0.001). ConclusionsT2 mapping could detect higher rate of patients with ICI-associated myocarditis than native T1 mapping, ER and LGE presence. LGE extent inversely correlated with left ventricular ejection fraction but positively correlated with native T1 value and extracellular volume in patients with ICI-associated myocarditis.

ENDOTHELIAL PROGENITOR CELLS ENGINEERED TO OVER-EXPRESS ENDOTHELIAL NO-SYNTHASE AND THEIR EFFECT ON ARRHYTHMIC SUBSTRATE AS ASSESSED BY GRAY ZONE ANALYSIS - A SUB-STUDY OF THE ENACT-AMI TRIAL

ENDOTHELIAL PROGENITOR CELLS ENGINEERED TO OVER-EXPRESS ENDOTHELIAL NO-SYNTHASE AND THEIR EFFECT ON ARRHYTHMIC SUBSTRATE AS ASSESSED BY GRAY ZONE ANALYSIS - A SUB-STUDY OF THE ENACT-AMI TRIAL

Artificial Intelligence for Contrast-Free MRI: Scar Assessment in Myocardial Infarction Using Deep Learning-Based Virtual Native Enhancement.

Myocardial scars are assessed noninvasively using cardiovascular magnetic resonance late gadolinium enhancement (LGE) as an imaging gold standard. A contrast-free approach would provide many advantages, including a faster and cheaper scan without contrast-associated problems. Virtual native enhancement (VNE) is a novel technology that can produce virtual LGE-like images without the need for contrast. VNE combines cine imaging and native T1 maps to produce LGE-like images using artificial intelligence. VNE was developed for patients with previous myocardial infarction from 4271 data sets (912 patients); each data set comprises slice position-matched cine, T1 maps, and LGE images. After quality control, 3002 data sets (775 patients) were used for development and 291 data sets (68 patients) for testing. The VNE generator was trained using generative adversarial networks, using 2 adversarial discriminators to improve the image quality. The left ventricle was contoured semiautomatically. Myocardial scar volume was quantified using the full width at half maximum method. Scar transmurality was measured using the centerline chord method and visualized on bull's-eye plots. Lesion quantification by VNE and LGE was compared using linear regression, Pearson correlation (R), and intraclass correlation coefficients. Proof-of-principle histopathologic comparison of VNE in a porcine model of myocardial infarction also was performed. VNE provided significantly better image quality than LGE on blinded analysis by 5 independent operators on 291 data sets (all P<0.001). VNE correlated strongly with LGE in quantifying scar size (R, 0.89; intraclass correlation coefficient, 0.94) and transmurality (R, 0.84; intraclass correlation coefficient, 0.90) in 66 patients (277 test data sets). Two cardiovascular magnetic resonance experts reviewed all test image slices and reported an overall accuracy of 84% for VNE in detecting scars when compared with LGE, with specificity of 100% and sensitivity of 77%. VNE also showed excellent visuospatial agreement with histopathology in 2 cases of a porcine model of myocardial infarction. VNE demonstrated high agreement with LGE cardiovascular magnetic resonance for myocardial scar assessment in patients with previous myocardial infarction in visuospatial distribution and lesion quantification with superior image quality. VNE is a potentially transformative artificial intelligence-based technology with promise in reducing scan times and costs, increasing clinical throughput, and improving the accessibility of cardiovascular magnetic resonance in the near future.

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.

Predictors of moderate to severe ischemic mitral regurgitation after myocardial infarction: a cardiac magnetic resonance study.

The purpose of this study is to explore the predictors of moderate to severe ischemic mitral regurgitation (IMR) after myocardial infarction with cardiovascular magnetic resonance (CMR). From January 2016 to September 2018, 109 patients (mean age 60 ± 8years) with IMR were studied retrospectively. All patients underwent CMR-cine with True-FISP sequence and late gadolinium enhancement (LGE) with a phase-sensitive inversion recovery sequence. The presence of papillary muscle infarction (PMI), global left ventricular (LV) infarcted extent, LV functional parameters, and LV myocardial strain were assessed. Univariate and multivariate analyses were performed to identify factors in the development of moderate to severe IMR. Mild IMR was present in 61 patients (56%), and moderate to severe IMR was present in 48 patients (44%). PMI was identified in 22 patients (20.1%); 14 of them (63.63%) showed a moderate or severe IMR. Global LV infarcted extent was increased in patients with moderate to severe IMR (p< 0.001). LV functional parameters of patients with moderate to severe IMR were statistically different from those of the patients with mild IMR (all p< 0.001), except the LV SV index (p= 0.142) and LV CI (p= 0.447). The global longitudinal strain (GLS), regional radial strain (RS), and circumferential strain (CS) of the moderate-to-severe IMR group were significantly decreased compared with those of the mild IMR group (p< 0.05). In multivariable analyses, age (OR = 1.11; p= 0.001), global LV infarct extent (OR = 1.14; p= 0.000), and GLS (OR = 1.31; p= 0.000) were associated with moderate-to-severe chronic IMR. The incidence of PMI was higher in patients with moderate-to-severe IMR. The extent of global LV infarcted extent and GLS were independent predictors of moderate-to-severe IMR. • Cardiovascular magnetic resonance late gadolinium enhancement and feature-tracking imaging provide reliable information on LV function, myocardial viability, and papillary muscle morphology. • Papillary muscle infarction is not an independent predictor of moderate-to-severe IMR. • The extent of global LV infarction and LV global longitudinal strain were independent predictors of moderate-to-severe chronic IMR.

Prevalence and pattern of cardiovascular magnetic resonance late gadolinium enhancement in highly trained endurance athletes

BackgroundIntensive endurance exercise may induce a broad spectrum of right ventricular (RV) adaptation/remodelling patterns. Late gadolinium enhancement (LGE) has also been described in cardiovascular magnetic resonance (CMR) of some endurance athletes and its clinical meaning remains controversial. Our aim was to characterize the features of contrast CMR and the observed patterns of the LGE distribution in a cohort of highly trained endurance athletes.MethodsNinety-three highly trained endurance athletes (> 12 h training/week at least during the last 5 years; 36 ± 6 years old; 53% male) and 72 age and gender-matched controls underwent a resting contrast CMR. In a subgroup of 28 athletes, T1 mapping was also performed.ResultsHigh endurance training load was associated with larger bi-ventricular and bi-atrial sizes and a slight reduction of biventricular ejection fraction, as compared to controls in both genders (p < 0.05). Focal LGE was significantly more prevalent in athletes than in healthy subjects (37.6% vs 2.8%; p < 0.001), with a typical pattern in the RV insertion points. In T1 mapping, those athletes who had focal LGE had higher extracellular volume (ECV) at the remote myocardium than those without (27 ± 2.2% vs 25.2 ± 2.1%; p < 0.05).ConclusionsHighly trained endurance athletes showed a ten-fold increase in the prevalence of focal LGE as compared to control subjects, always confined to the hinge points. Additionally, those athletes with focal LGE demonstrated globally higher myocardial ECV values. This matrix remodelling and potential presence of myocardial fibrosis may be another feature of the athlete’s heart, of which the clinical and prognostic significance remains to be determined.

What is the mid-wall linear high intensity \u201clesion\u201d on cardiovascular magnetic resonance late gadolinium enhancement?

BackgroundCardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) is a valuable technique for detecting myocardial disorders and fibrosis. However, we sometimes observe a linear, mid-wall high intensity signal in the basal septum in the short axis view, which often presents diagnostic difficulties in the clinical setting. The purpose of this study was to compare the linear, mid-wall high intensity in the basal septum identified by LGE with the anterior septal perforator arteries identified by coronary computed tomography angiography (CorCTA).MethodsWe retrospectively selected 148 patients who underwent both CorCTA and CMR LGE within 1 year. In the interpretation of LGE, we defined a positive linear high intensity (LHI+) as follows: ① LHI in the basal septum and ② observable for 1.5 cm or more. All other patients were defined as a negative LHI (LHI-). In LHI+ patients, we assessed the correlation between the LHI length and the septal perforator artery length on CorCTA. We also compared the length of the septal perforator artery on CorCTA between LHI+ patients and LHI- patients.Results A population of 111 patients were used for further analysis. Among these , there were 55 LHI+ patients and 56 LHI- patients. In LHI+ patients, linear regression analysis revealed that there was a good agreement between LGE LHI and septal perforator arteries by CorCTA in terms of length measurements. The measured length of the anterior septal perforator arteries was significantly shorter in LHI- patients than in LHI+ patients (10 ± 8 mm vs. 21 ± 8 mm; P < 0.05).ConclusionsThe LHI observed in the basal septum on short axis LGE may reflect contrast enhancement of the anterior septal perforator arteries. It is important to interpret this septal LHI against knowledge of anatomic structure, to avoid misinterpretations of LGE and prevent misdiagnosis.

Echocardiography and cardiovascular magnetic resonance based evaluation of myocardial strain and relationship with late gadolinium enhancement

ObjectivesWe sought to: (1) determine the agreement in cardiovascular magnetic resonance (CMR) and speckle tracking echocardiography (STE) derived strain measurements, (2) compare their reproducibility, (3) determine which approach is best related to CMR late gadolinium enhancement (LGE).BackgroundWhile STE-derived strain is routinely used to assess left ventricular (LV) function, CMR strain measurements are not yet standardized. Strain can be measured using dedicated pulse sequences (strain-encoding, SENC), or post-processing of cine images (feature tracking, FT). It is unclear whether these measurements are interchangeable, and whether strain can be used as an alternative to LGE.MethodsFifty patients underwent 2D echocardiography and 1.5 T CMR. Global longitudinal strain (GLS) was measured by STE (Epsilon), FT (NeoSoft) and SENC (Myocardial Solutions) and circumferential strain (GCS) by FT and SENC.ResultsGLS showed good inter-modality agreement (r-values: 0.71–0.75), small biases (< 1%) but considerable limits of agreement (− 7 to 8%). The agreement between the CMR techniques was better for GLS than GCS (r = 0.81 vs 0.67; smaller bias). Repeated measurements showed low intra- and inter-observer variability for both GLS and GCS (intraclass correlations 0.86–0.99; coefficients of variation 3–13%). LGE was present in 22 (44%) of patients. Both SENC- and FT-derived GLS and GCS were associated with LGE, while STE-GLS was not. Irrespective of CMR technique, this association was stronger for GCS (AUC 0.77–0.78) than GLS (AUC 0.67–0.72) and STE-GLS (AUC = 0.58).ConclusionThere is good inter-technique agreement in strain measurements, which were highly reproducible, irrespective of modality or analysis technique. GCS may better reflect the presence of underlying LGE than GLS.

Ejection fraction in left bundle branch block is disproportionately reduced in relation to amount of myocardial scar

IntroductionThe relationship between left ventricular (LV) ejection fraction (EF) and LV myocardial scar can identify potentially reversible causes of LV dysfunction. Left bundle branch block (LBBB) alters the electrical and mechanical activation of the LV. We hypothesized that the relationship between LVEF and scar extent is different in LBBB compared to controls. MethodsWe compared the relationship between LVEF and scar burden between patients with LBBB and scar (n = 83), and patients with chronic ischemic heart disease and scar but no electrocardiographic conduction abnormality (controls, n = 90), who had undergone cardiovascular magnetic resonance (CMR) imaging at one of three centers. LVEF (%) was measured in CMR cine images. Scar burden was quantified by CMR late gadolinium enhancement (LGE) and expressed as % of LV mass (%LVM). Maximum possible LVEF (LVEFmax) was defined as the function describing the hypotenuse in the LVEF versus myocardial scar extent scatter plot. Dysfunction index was defined as LVEFmax derived from the control cohort minus the measured LVEF. ResultsCompared to controls with scar, LBBB with scar had a lower LVEF (median [interquartile range] 27 [19–38] vs 36 [25–50] %, p < 0.001), smaller scar (4 [1–9] vs 11 [6–20] %LVM, p < 0.001), and greater dysfunction index (39 [30–52] vs 21 [12–35] % points, p < 0.001). ConclusionsAmong LBBB patients referred for CMR, LVEF is disproportionately reduced in relation to the amount of scar. Dyssynchrony in LBBB may thus impair compensation for loss of contractile myocardium.

Quantification of myocardial infarct area based on TRAFFn relaxation time maps - comparison with cardiovascular magnetic resonance late gadolinium enhancement, T1\u03c1 and T2 in vivo

BackgroundTwo days after myocardial infarction (MI), the infarct consists mostly on necrotic tissue, and the myocardium is transformed through granulation tissue to scar in two weeks after the onset of ischemia in mice. In the current work, we determined and optimized cardiovascular magnetic resonance (CMR) methods for the detection of MI size during the scar formation without contrast agents in mice.MethodsWe characterized MI and remote areas with rotating frame relaxation time mapping including relaxation along fictitious field in nth rotating frame (RAFFn), T1ρ and T2 relaxation time mappings at 1, 3, 7, and 21 days after MI. These results were compared to late gadolinium enhancement (LGE) and Sirius Red-stained histology sections, which were obtained at day 21 after MI.ResultsAll relaxation time maps showed significant differences in relaxation time between the MI and remote area. Areas of increased signal intensities after gadolinium injection and areas with increased TRAFF2 relaxation time were highly correlated with the MI area determined from Sirius Red-stained histology sections (LGE: R2 = 0.92, P < 0.01, TRAFF2: R2 = 0.95, P < 0.001). Infarct area determined based on T1ρ relaxation time correlated highly with Sirius Red histology sections (R2 = 0.97, P < 0.01). The smallest overestimation of the LGE-defined MI area was obtained for TRAFF2 (5.6 ± 4.2%) while for T1ρ overestimation percentage was > 9% depending on T1ρ pulse power.ConclusionT1ρ and TRAFF2 relaxation time maps can be used to determine accurately MI area at various time points in the mouse heart. Determination of MI size based on TRAFF2 relaxation time maps could be performed without contrast agents, unlike LGE, and with lower specific absorption rate compared to on-resonance T1ρ relaxation time mapping.

Reverse Myocardial Remodeling Following Valve Replacement in Patients With Aortic Stenosis

BackgroundLeft ventricular (LV) hypertrophy, a key process in human cardiac disease, results from cellular (hypertrophy) and extracellular matrix expansion (interstitial fibrosis). ObjectivesThis study sought to investigate whether human myocardial interstitial fibrosis in aortic stenosis (AS) is plastic and can regress. MethodsPatients with symptomatic, severe AS (n = 181; aortic valve area index 0.4 ± 0.1 cm2/m2) were assessed pre–aortic valve replacement (AVR) by echocardiography (AS severity, diastology), cardiovascular magnetic resonance (CMR) (for volumes, function, and focal or diffuse fibrosis), biomarkers (N-terminal pro–B-type natriuretic peptide and high-sensitivity troponin T), and the 6-min walk test. CMR was used to measure the extracellular volume fraction (ECV), thereby deriving matrix volume (LV mass × ECV) and cell volume (LV mass × [1 − ECV]). Biopsy excluded occult bystander disease. Assessment was repeated at 1 year post-AVR. ResultsAt 1 year post-AVR in 116 pacemaker-free survivors (age 70 ± 10 years; 54% male), mean valve gradient had improved (48 ± 16 mm Hg to 12 ± 6 mm Hg; p < 0.001), and indexed LV mass had regressed by 19% (88 ± 26 g/m2 to 71 ± 19 g/m2; p < 0.001). Focal fibrosis by CMR late gadolinium enhancement did not change, but ECV increased (28.2 ± 2.9% to 29.9 ± 4.0%; p < 0.001): this was the result of a 16% reduction in matrix volume (25 ± 9 ml/m2 to 21 ± 7 ml/m2; p < 0.001) but a proportionally greater 22% reduction in cell volume (64 ± 18 ml/m2 to 50 ± 13 ml/m2; p < 0.001). These changes were accompanied by improvement in diastolic function, N-terminal pro–B-type natriuretic peptide, 6-min walk test results, and New York Heart Association functional class. ConclusionsPost-AVR, focal fibrosis does not resolve, but diffuse fibrosis and myocardial cellular hypertrophy regress. Regression is accompanied by structural and functional improvements suggesting that human diffuse fibrosis is plastic, measurable by CMR and a potential therapeutic target. (Regression of Myocardial Fibrosis After Aortic Valve Replacement; NCT02174471)

Coronary microvascular function and myocardial fibrosis in women with angina pectoris and no obstructive coronary artery disease: the iPOWER study

BackgroundEven in absence of obstructive coronary artery disease women with angina pectoris have a poor prognosis possibly due to coronary microvascular disease. Coronary microvascular disease can be assessed by transthoracic Doppler echocardiography measuring coronary flow velocity reserve (CFVR) and by positron emission tomography measuring myocardial blood flow reserve (MBFR). Diffuse myocardial fibrosis can be assessed by cardiovascular magnetic resonance (CMR) T1 mapping. We hypothesized that coronary microvascular disease is associated with diffuse myocardial fibrosis.MethodsWomen with angina, a clinically indicated coronary angiogram with <50 % stenosis and no diabetes were included. CFVR was measured using dipyridamole (0.84 mg/kg) and MBFR using adenosine (0.84 mg/kg). Focal fibrosis was assessed by 1.5 T CMR late gadolinium enhancement (0.1 mmol/kg) and diffuse myocardial fibrosis by T1 mapping using a modified Look-Locker pulse sequence measuring T1 and extracellular volume fraction (ECV).ResultsCFVR and CMR were performed in 64 women, mean (SD) age 62.5 (8.3) years. MBFR was performed in a subgroup of 54 (84 %) of these women. Mean native T1 was 1023 (86) and ECV (%) was 33.7 (3.5); none had focal fibrosis. Median (IQR) CFVR was 2.3 (1.9; 2.7), 23 (36 %) had CFVR < 2 indicating coronary microvascular disease, and median MBFR was 2.7 (2.2; 3.0) and 19 (35 %) had a MBFR value below 2.5. No significant correlations were found between CFVR and ECV or native T1 (R2 = 0.02; p = 0.27 and R2 = 0.004; p = 0.61, respectively). There were also no correlations between MBFR and ECV or native T1 (R2 = 0.1; p = 0.13 and R2 = 0.004, p = 0.64, respectively). CFVR and MBFR were correlated to hypertension and heart rate.ConclusionIn women with angina and no obstructive coronary artery disease we found no association between measures of coronary microvascular disease and myocardial fibrosis, suggesting that myocardial ischemia induced by coronary microvascular disease does not elicit myocardial fibrosis in this population. The examined parameters seem to provide independent information about myocardial and coronary disease.

Diagnostic Accuracy of Cardiac Magnetic Resonance Imaging in the Detection and Characterization of Left Atrial Catheter Ablation Lesions: A Multicenter Experience

We tested the hypothesis that cardiovascular magnetic resonance (CMR) imaging can reliably distinguish the presence or absence of left atrial (LA) ablation lesions by blinded analysis of pre- and postablation imaging. Consecutive patients at 2 centers undergoing pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation by either wide area circumferential radiofrequency ablation (WACA) or ostial ablation with a cryoballoon underwent CMR late gadolinium enhancement (LGE) imaging pre- and 3 months postablation. Imaging was anonymized for blinded analysis of (1) LGE images, and (2) a 3D fusion image with LGE projected onto a segmented LA surface. Scans were categorized using both assessment techniques separately as pre- or postablation, and if postablation, whether lesions were in an ostial or WACA distribution. LGE imaging was performed in 50 patients (aged 60 ± 10 years, 68% male, 24 underwent WACA and 26 had cryoablation). Sensitivity and specificity for detection of ablation lesions was 60% and 96% on LGE imaging. Sensitivity was higher using 3D fusion imaging (88%; P = 0.003). The proportion in whom lesions were both detected and the distribution correctly assessed as WACA or ostial was higher with 3D fusion imaging compared to LGE imaging (54% vs 28%; P = 0.014). There was no difference in the detection of radiofrequency ablation lesions compared to cryoablation lesions (58% vs 62%; P = 1.000). LGE imaging of atrial scar is not yet sufficiently accurate to reliably identify ablation lesions or to determine lesion distribution.

Myocardial Crypts

It is more than 50 years since the first modern description of hypertrophic cardiomyopathy (HCM).1 Understanding has been driven by technology, with the first descriptions focusing on clinical examination, ECG changes, and histological changes from autopsy study. As technology evolved from ventriculography, M-mode, then 2-dimensional echocardiography, and cardiovascular magnetic resonance (CMR), understanding has evolved and the known phenotype of the disease has extended. Recent notable examples of this have been hypertrophy missed by echo, particularly but not exclusively at the apex, mitral valve abnormalities, apical aneurysms, and proposed familial criteria, where even subtle abnormalities may be adjudged significant in the context of a pretest probability of 50% of genetic mutation carriage. In this issue of Circulation: Cardiovascular Imaging , Maron et al2 have explored the potential significance of myocardial crypts. These “architectural abnormalities” of the left ventricle (LV) occur particularly in the septum and inferior (posterior) right ventricular (RV) insertion point and had been observed at increased frequency in HCM. …