Konrad Werys

Magnetic resonance imaging assessment of intraventricular dyssynchrony and delayed enhancement as predictors of response to cardiac resynchronization therapy in patients with heart failure of ischaemic and non-ischaemic etiologies

PURPOSEnTo assess the value of dyssynchrony and myocardial viability assessment by cardiac magnetic resonance (CMR) in prediction of response to cardiac resynchronization therapy (CRT) in patients with heart failure (HF) of both ischaemic and non-ischaemic etiologies.nnnMATERIALS AND METHODSnPatients scheduled for CRT in NYHA class II-IV, left ventricular ejection fraction <35%, QRS ≥ 120 ms were included. Tagged cine and late gadolinium enhancement (LGE) images were performed. Dyssynchrony was assessed with inTag toolbox and LGE was quantified using cutoff value at half of maximal signal in the scar. Cardiopulmonary exercise test, echocardiography and blood testing for NT-proBNP levels were done at baseline and 6 months after CRT.nnnRESULTSn52 patients (age 60.3 ± 13 years) were included. 26 patients (50%) met response criteria. The ischaemic etiology of HF was more frequent (69% vs. 31%, p=0.002), the percent of LGE was higher (7.7% [0-13.5%] vs. 19.0% (0-31.9%], p=0.013), regional vector of circumferential strain variance (RVV) was lower (0.27 ± 0.08 vs. 0.34 ± 0.09, p=0.009) and uniformity of radial strain was higher (0.72 ± 0.25 vs. 0.56 ± 0.29, p=0.046) in non-responders vs. responders. Multivariate logistic regression showed that RVV predicted response to CRT (HR 2.3, 95% CI 1.02-5.02, p=0.0430) independently of LGE and the etiology of heart failure. In the subgroup of patients with ischaemic HF the extend of transmural scar within myocardium was higher in non-responders vs. responders (26.3% vs. 15.0% respectively, p=0.01) and was a predictor of response to CRT in univariable analysis (HR 0.87, 95% CI 0.77-0.98, p=0.025) providing the sensitivity of 76% and specificity of 75% at the cutoff point of 18% in the prediction of poor response to CRT. In patients with non-ischaemic HF QRS was wider (162 ms vs. 140 ms, p=0.04), regional vector of strain variance (RVV) was higher (0.39 vs. 0.25, p=0.002) and uniformity of radial strain was lower (0.52 vs. 0.80, p=0.049) in non-responders vs. responders. Univariable logistic regression showed that RVV was a predictor of response to CRT (HR 1.50, 95% CI 1.06-2.13, p=0.022), providing the sensitivity of 94% and specificity of 85% at the cutoff point of 0.31.nnnCONCLUSIONSnCMR derived parameters of dyssynchrony such as RVV may provide an additive value in prediction of response to CRT, especially in patients with non-ischaemic etiology of heart failure. In patients with ischaemic HF the transmurality of LGE is an important predictor of lack of response to CRT.

Native T1-mapping for non-contrast assessment of myocardial fibrosis in patients with hypertrophic cardiomyopathy — comparison with late enhancement quantification☆

BACKGROUNDnMyocardial fibrosis was shown to influence prognosis in hypertrophic cardiomyopathy (HCM). It is typically assessed by late gadolinium enhancement (LGE) on cardiac magnetic resonance. Native T1-mapping has been proposed, as a contrast-free method of fibrosis assessment. The aim of the study was to define a cut-off value for native T1 relaxation time that best reflects LGE quantification of myocardial fibrosis.nnnMETHODSnIn 25 patients with HCM and 20 controls we performed T1-mapping pre-contrast using ShMOLLI technique. This was followed by LGE assessment in the studied group 10 minutes after gadolinium contrast injection. Relative myocardial fibrosis size was calculated for varying T1 time thresholds (940-1100 ms) and compared with 6 standard deviations (6SD) method for LGE.nnnRESULTSnMedian fibrosis size calculated with T1-mapping was insignificantly different from LGE only for native T1 time threshold of 1060 ms (p = 0.62). Using this threshold, Bland-Altman plots demonstrated very good agreement between fibrosis sizes from the two methods (slightly better only for 1080 ms threshold). For threshold of 1060 ms we also observed good correlation (rho = 0.73) with LGE 6SD method (insignificantly better for lower thresholds, best for threshold of 980 ms-rho = 0.88). In control group with no diagnosis of HCM, fibrosis size <1% was reached for thresholds of 1040 ms and higher.nnnCONCLUSIONnNative T1-mapping can be used for non-contrast assessment of myocardial fibrosis in HCM. The 1060 ms threshold of the native T1 relaxation time is characterized by the best balance between agreement and correlation with fibrosis assessed by LGE 6SD method.

Cine dyscontractility index: A novel marker of mechanical dyssynchrony that predicts response to cardiac resynchronization therapy.

To investigate whether magnetic resonance imaging (MRI) cine‐derived dyssynchrony indices provide additional information compared to conventional tagged MRI (tMRI) acquisitions in heart failure patients undergoing cardiac resynchronization therapy (CRT).

Systolic myocardial volume gain in dilated, hypertrophied and normal heart. CMR study

AIMnTo investigate changes in myocardial tissue volume during the cardiac cycle to verify the hypothesis of non-compressibility of the myocardium in healthy individuals (HI) as well as in patients with hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and aortic stenosis (AS).nnnMATERIALS AND METHODSnThe study group included 30 HI, and patients with HCM (n=110), DCM (n=89), and AS (n=78). Left ventricular (LV) function, end-diastolic, and end-systolic volumes were calculated based on cardiac magnetic resonance imaging (CMR) for all participants.nnnRESULTSnEnd-systolic myocardial volumes were higher than end-diastolic in both controls (91.2±26.6 versus 85.1±24.3xa0ml, p<0.001) and in all patient groups: HCM (214.3±81.6 versus 176±64.2xa0ml, p<0.01), DCM (128.4±43.1 versus 115.4±42.9xa0ml, p<0.001) and AS (155.1±37.1 versus 129.4±34.6xa0ml, p<0.001). HCM and AS patients had significantly higher systolic volume gain than HI (21.5±8.3 versus 10.6±6.3%, p<0.01 and 18.3±5.7 versus 10.6±6.3% p=0.013, respectively). Conversely, DCM patients had lesser increases in myocardial systolic volume than HCM patients (11.2±4.8% versus 21.5±8.3, p=0.01) and AS patients (11.2±4.8% versus 18.3±5.7, p=0.02). No differences were found in systolic volume gain between AS and HCM patients (p=ns) or between DCM patients and HI (p=ns).nnnCONCLUSIONnEnd-systolic myocardial volume was significantly higher than end-diastolic volume in all subsets of patients. The systolic volume gain was greater in individuals with hypertrophy than in those without.

CINE-MRI to study the progress of disease in a chronic atrial fibrillation goat model

Background Atrial fibrillation (AF) is a common sustained cardiac arrhythmia associated with increased risks of heart failure, left ventricle (LV) dysfunction, and known to cause an increase in left atrium (LA) volume with decrease in atrial contractility. Cine magnetic resonance images (MRI) were used to measure changes in LA and LV function in a chronic AF goat model. Ejection fraction (EF), end diastolic volume (EDV), end systolic volume (ESV), and stroke volume (SV) measurements of both the LV and LA were made from cine-MR images to track the progression of disease in goats that were induced with AF using neurostimulators. Methods

Right ventricular end-systolic area as a simple first-line marker predicting right ventricular enlargement and decreased systolic function in children referred for cardiac magnetic resonance imaging

AIMnTo assess the accuracy of simple cardiovascular magnetic resonance imaging (CMR) parameters for first-line analysis of right ventricle (RV) dysfunction in children to identify those who require in-depth analysis and those in whom simple assessment is sufficient.nnnMATERIALS AND METHODSnSixty paediatric CMR studies were analysed. The following CMR parameters were measured: RV end-diastolic and end-systolic area (4CH EDA and 4CH ESA), fractional area change (FAC), RV diameter in end-diastole (RVD1), tricuspid annular plane systolic excursion (TAPSE), and RV outflow tract diameter in end-diastole (RVOT prox). They were correlated with RV end-diastolic volume (RVEDVI) and RV ejection fraction (RVEF).nnnRESULTSnRVEDVI correlated best with 4CH ESA (r=0.85, <0.001) and EDA (r=0.82, <0.001). For RVEF only a moderate reverse correlation was found for 4CH ESA (-0.56, <0.001), 4CH EDA (-0.49, 0.001) and positive correlation for FAC (0.49, <0.001). There was no correlation between TAPSE and RVEF and only weak between RVD1 and RVEDVI. A 4CH ESA cut-off value of 8.5xa0cm2/m2 had a very high diagnostic accuracy for predicting an enlarged RV (AUC=0.912, p<0.001, sensitivity 92.3%, specificity 79%) and a cut-off value of 10.5xa0cm2/m2 was also a good predictor of depressed RV systolic function (AUC=0.873, p<0.001, sensitivity 83%, specificity 89%).nnnCONCLUSIONnFor routine screening in clinical practice, 4CH ESA seems a reliable and easy method to identify patients with RV dysfunction.

Block matching and B-spline methods in deformation estimation in synthetic left ventricular model with nontransmural infarction

The cardiac elastography aims at identification of non-transmural infarctions. Two displacement estimation methods in such an application using synthetic ultrasonic data are studied. Reference was obtained from Finite Element Modelling. Models had the form of half of an ellipsoid with 15 mm wall thickness. The homogenous model, models with transmural and nontransmural inclusion were designed. Deformation of the models was simulated using Abaqus. Ultrasonic data of LAX and SAX views were generated using Field II. Radial (dR) and lateral (dL) displacements were estimated using a 2D correlation search with 2D stretching (2DCS) and B-spline (BS) method. Strains were estimated using least squares estimator. Mean Absolute Error (MAE) of the dR in the LAX view was approx. 6[μm] for 2DCS and 8[μm] for BS, that of the dL 30 and 24[μm] respectively. MAE of the second component of the principal strain (epsilon)2 was 0.10 and 0.14[%], respectively. Corresponding values for SAX view were 7, 10, 42, 52[μm] and 0.47 and 1.08[%]. In the LAX view both estimation methods result in the (epsilon)2 behavior coherent with the presence of the inclusion, with the 2DCS results closer to the reference. In the SAX view the BS approach results in high errors of the estimate. The (epsilon)2 profiles, LAX view, show minor discrepancies with respect to the reference and show the effect of the inclusion. The (epsilon)2 profiles, SAX view, obtained from displacements estimated using the BS method strongly deviate from the reference. Block matching performs better in application to the local strain estimation.

Four-dimensional flow magnetic resonance imaging in hypertrophic obstructive cardiomyopathy

Address for correspondence: Mateusz Śpiewak, MD, PhD, Magnetic Resonance Unit, Department of Radiology, Institute of Cardiology, ul. Alpejska 42, 04–628, Warszawa, Poland, e-mail: mspiewak@ikard.pl Conflict of interest: This work was supported by the Ministry of Science and Higher Education, Iuventus Plus (grant number IP 2014 0477 73 to M. Śpiewak). Kardiologia Polska Copyright

Quantification of mitral regurgitation in patients with hypertrophic cardiomyopathy using aortic and pulmonary flow data: impacts of left ventricular outflow tract obstruction and different left ventricular segmentation methods

BackgroundCardiovascular magnetic resonance (CMR) imaging in patients with hypertrophic cardiomyopathy (HCM) enables the assessment of not only left ventricular (LV) hypertrophy and scarring but also the severity of mitral regurgitation. CMR assessment of mitral regurgitation is primarily based on the difference between LV stroke volume (LVSV) and aortic forward flow (Ao) measured using the phase-contrast (PC) technique. However, LV outflow tract (LVOT) obstruction causing turbulent, non-laminar flow in the ascending aorta may impact the accuracy of aortic flow quantification, leading to false conclusions regarding mitral regurgitation severity. Thus, we decided to quantify mitral regurgitation in patients with HCM using Ao or, alternatively, main pulmonary artery forward flow (MPA) for mitral regurgitation volume (MRvol) calculations.MethodsThe analysis included 143 prospectively recruited subjects with HCM and 15 controls. MRvol was calculated as the difference between LVSV computed with either the inclusion (LVSVincl) or exclusion (LVSVexcl) of papillary muscles and trabeculations from the blood pool and either Ao (MRvolAoi or MRvolAoe) or MPA (MRvolMPAi or MRvolMPAe). The presence or absence of LVOT obstruction was determined based on Doppler echocardiography findings.ResultsMRvolAoi was higher than MRvolMPAi in HCM patients with LVOT obstruction [47.0xa0ml, interquartile range (IQR)u2009=u200931.5–60.0 vs. 35.5xa0ml, IQRu2009=u200926.0–51.0; pxa0<u20090.0001] but not in non-obstructive HCM patients (23.0xa0ml, IQRu2009=u200916.0–32.0 vs. 24.0xa0ml, IQRu2009=u200915.3–32.0; pu2009=u20090.26) or controls (18.0xa0ml, IQRu2009=u200914.3–21.8 vs. 20.0xa0ml, IQRu2009=u200914.3–22.0; pu2009=u20090.89). In contrast to controls and HCM patients without LVOT obstruction, in HCM patients with LVOT obstruction, aortic flow-based MRvol (MRvolAoi) was higher than pulmonary-based findings (MRvolMPAi) (biasu2009=u20099.5xa0ml; limits of agreement: −11.7–30.7 with a difference of 47xa0ml in the extreme case). The differences between aortic-based and pulmonary-based MRvol values calculated using LVSVexcl mirrored those derived using LVSVincl. However, MRvol values calculated using LVSVexcl were lower in all the groups analyzed (HCM with LVOT obstruction, HCM without LVOT obstruction, and controls) and with all methods of MRvol quantification used (pu2009≤u20090.0001 for all comparisons).ConclusionsIn HCM patients, LVOT obstruction significantly affects the estimation of aortic flow, leading to its underestimation and, consequently, to higher MRvol values than those obtained with MPA-based MRvol calculations.

Biventricular mechanics in prediction of severe myocardial fibrosis in patients with dilated cardiomyopathy: CMR study

PURPOSEnThe purpose of this study was to compare the ability of various parameters of myocardial mechanics to predict large amounts of biventricular fibrosis assessed via T1 mapping in patients with dilated cardiomyopathy (DCM).nnnMATERIALnCardiovascular magnetic resonance feature tracking analysis and T1 mapping were performed in 26 patients with DCM [mean age: 34.4±9.1years, 15 (57.6%) males]. The values of various parameters of myocardial mechanics at predicting advanced left-ventricle (LV) and right-ventricle (RV) fibrosis were compared using logistic regression analysis and receiver operating characteristic curve (ROC) analysis.nnnRESULTSnThere were 7 (26.9%) patients with a large amount of LV fibrosis and 9 (34.6%) patients with severe RV fibrosis. ROC curve analysis revealed that the model of combined LV strain rates (AUC=0.902) offered superb ability at predicting large amounts of LV fibrosis. The models including RV strain rates (AUC=0.974), a combination of RV strains, strain rates and clinical parameters (AUC=0.993) as well as the RV radial strain rate alone model (AUC=0.961) yielded outstanding performance in discriminating large and small amounts of RV fibrosis. In multivariate analysis, the LV circumferential strain (LVCR) and RV radial (RVR) strain rate were the only independent predictors of large amounts of LV and RV fibrosis, respectively.nnnCONCLUSIONSnIndices of myocardial deformation, especially combined with clinical features, offered a superlative ability to differentiate high from low degrees of fibrosis in DCM patients. Among all analyzed parameters of myocardial mechanics, LVCR and RVR rate alone were the independent predictors of high degrees of LV and RV fibrosis, respectively.