Cardiac Magnetic Resonance Feature Tracking Research Articles

Incremental prognostic value of left atrial and biventricular feature tracking in dilated cardiomyopathy: a long-term study

BackgroundDespite the use of cardiovascular magnetic resonance (CMR) feature tracking (FT) imaging to detect myocardial deformation, the optimal strain index in dilated cardiomyopathy (DCM) is unclear. This study aimed to determine whether atrial and biventricular strains can provide the greatest or joint incremental prognostic value in patients with DCM over a long follow-up period. MethodsFour hundred-twelve DCM patients were included retrospectively. Comprehensive clinical evaluation and imaging investigations were obtained, including measurements of CMR-FT derived left atrial (LA) reservoir, conduit, booster strain (εs, εe, εa); left ventricular (LV) and right ventricular (RV) global longitudinal, radial, circumferential strain (GLS, GRS, GCS). All patients were followed up for major adverse cardiac events (MACE) including all-cause mortality, heart transplantation, and implantable cardioverter defibrillator discharge. The predictors of MACE were examined with univariable and multivariable Cox regression analysis. Subsequently, nested Cox regression models were built to evaluate the incremental prognostic value of strain parameters. The incremental predictive power of strain parameters was assessed by Omnibus tests, and the model performance and discrimination were evaluated by Harrell C-index and integrated discrimination improvement (IDI) analysis. Patient survival was illustrated by Kaplan–Meier curves and differences were evaluated by log-rank test. ResultsDuring a median follow-up of 5.0 years, MACE were identified in 149 (36%) patients. LAεe, LVGLS, and RVGLS were the most predictive strain parameters for MACE (AUC: 0.854, 0.733, 0.733, respectively). Cox regression models showed that the predictive value of LAεe was independent from and incremental to LVGLS, RVGLS, and baseline variables (HR 0.74, 95% CI 0.68–0.81, P < 0.001). In reclassification analysis, the addition of LAεe provided the best discrimination of the model (χ2 223.34, P < 0.001; C-index 0.833; IDI 0.090, P < 0.001) compared with LVGLS and RVGLS models. Moreover, LAεe with a cutoff of 5.3% further discriminated the survival probability in subgroups of patients with positive LGE or reduced LVEF (all log-rank P < 0.001). ConclusionLAεe provided the best prognostic value over biventricular strains and added incremental value to conventional clinical predictors for patients with DCM.

Effects of spatial and temporal resolution on cardiovascular magnetic resonance feature tracking measurements using a simple realistic numerical phantom.

To develop a single-slice numerical phantom with known myocardial motion, at several temporal and in-plane spatial resolutions, for testing and comparison of Cardiovascular Magnetic Resonance (CMR) feature tracking (FT) software. The phantom was developed based on CMR acquisitions of one volunteer (acquired cine, tagging cine, T1 map, T2 map, proton density weighted image). The numerical MRI simulator JEMRIS was used, and the phantom was generated at several in-plane spatial resolutions (1.4 × 1.4 mm2 to 3.0 × 3.0 mm2) and temporal resolutions (20 to 40 cardiac phases). Two feature tracking software packages were tested: Medical Image Tracking Toolbox (MITT) and two versions of cvi42 (v5.3.8 and v5.13.7). The effect of resolution on strain results was investigated with reference to ground-truth radial and circumferential strain. Peak radial strain was consistently undermeasured more for cvi42 v5.13.7 than for v5.3.8. Increased pixel size produced a trend of increased difference from ground-truth peak strain, with the largest changes for cvi42 obtained using v5.13.7 between 1.4 × 1.4 mm2 and 3.0 × 3.0 mm2, at 9.17 percentage points (radial) and 8.42 percentage points (circumferential). The results corroborate the presence of intervendor differences in feature tracking results and show the magnitude of strain differences between software versions. This study shows how temporal and in-plane spatial resolution can affect feature tracking with reference to the ground-truth strain of a numerical phantom. Results reaffirm the need for numerical phantom development for the validation and testing of FT software.

Relevance of subclinical right ventricular dysfunction measured by feature-tracking cardiac magnetic resonance in non-ischemic dilated cardiomyopathy

BackgroundRight ventricular (RV) dysfunction in patients with non-ischemic dilated cardiomyopathy (NICM) is associated with cardiovascular events. To analyze the feasibility of assessing RV myocardial deformation by feature tracking (FT)-cardiac magnetic resonance (CMR), and its usefulness as a prognostic marker.MethodsRetrospective study of NICM patients undergoing CMR. Longitudinal FT-RV free wall (LFT-RVFW) and fractional area change (FAC) were obtained. Correlation with standard RV parameters was studied. An association with combined event (heart failure (HF), ICD implantation or cardiovascular death) was assessed using a logistic regression model.Results98 patients (64 ± 13 years) were included. Left ventricular (LV) systolic function (LVEF 29.5 ± 9.6%, 47% with LVEF ≥ 30%) and RV (RVEF 52.2 ± 14.6%, 72% with RVEF ≥ 45%). Follow-up of 38 ± 17 months, 26.5% presented at least one admission for HF. An excellent correlation of LFT-RVFW (r = 0.82) and FAC (r = 0.83) with RVEF was evident. No association of RV-FT parameters with prognosis entire study population was found. However, in patients with LVEF ≥ 30%, admissions for HF were associated with lower LFT-RVFW (−21.6 ± 6.6% vs −31.3 ± 10%; p = 0.006) and FAC (36.6 ± 9.6% vs 50.5 ± 13.4%; p < 0.001) values. Similar differences were observed when only patients with RVEF ≥ 45% were considered. An LFT-RVFW cut-off point of -19.5% and FAC of 36.5% showed good prognostic performance. Decreased LFT-RVFW or FAC represented an independent predictor of combined event in patients with LVEF ≥ 30%.ConclusionsIn NICM patients without severe LV dysfunction, decreased values of LFT-RVFW and/or FAC were associated with HF admissions, independently of RVEF.

Early longitudinal changes in left ventricular function and morphology in diabetic pigs: evaluation by 3.0T magnetic resonance imaging

BackgroundPrevious researches on large animal models of diabetic cardiomyopathy were insufficient. The aim of this study was to evaluate early changes in left ventricular (LV) function and morphology in diabetic pigs using a cardiac magnetic resonance (CMR) time-volume curve and feature tracking technique.MethodsStreptozotocin (STZ) was used to induce diabetic in sixteen pigs. 3.0T MRI scanned the pig’s heart before and 2, 6, 10 and 16 months after modelling. CMR biomarkers, including time-volume curve and myocardial strain, were compared to analyse the longitudinal changes in LV function and morphology. Pearson correlation was used to evaluate the relationship between LV strain and remodelling. Cardiac specimens were obtained at 6, 10, and 16 months after modelling to observe the myocardial ultrastructural and microstructure at different courses of diabetes.ResultsTwelve pigs developed diabetes. The 80% diastolic volume recovery rate (DVR) at 6 months after modelling was significantly higher than that before modelling (0.78 ± 0.08vs. 0.67 ± 0.15). The LV global longitudinal peak strain (GLPS) (− 10.21 ± 3.15 vs. − 9.74 ± 2.78 vs. − 9.38 ± 3.71 vs. − 8.71 ± 2.68 vs. − 6.59 ± 2.90%) altered gradually from the baseline data to 2, 6, 10 and 16 months after modelling. After 16 months of modelling, the LV remodelling index (LVRI) of pigs increased compared with that before modelling (2.19 ± 0.97 vs. 1.36 ± 0.45 g/ml). The LVRI and myocardial peak strain were correlated in diabetic pigs (r= − 0.40 to − 0.54), with GLPS being the most significant. Electron microscopy and Masson staining showed that myocardial damage and fibrosis gradually increased with the progression of the disease.ConclusionIntravenous injection of STZ can induce a porcine diabetic cardiomyopathy model, mainly characterized by decreased LV diastolic function and strain changes accompanied by myocardial remodelling. The changes in CMR biomarkers could reflect the early myocardial injury of diabetic cardiomyopathy.

The association of left atrial mechanics with left ventricular morphology in patients with hypertrophic cardiomyopathy: a cardiac magnetic resonance study.

Hypertrophic cardiomyopathy (HCM) is related with structural and pathologic changes in the left atrium (LA) and left ventricle (LV). The aim of this study was to explore the association between LA mechanics and LV characteristics in patients with HCM using cardiac magnetic resonance feature tracking (CMR-FT). A total of 76 patients with HCM and 26 healthy controls were included in the study. The parameters including the extent of LV late gadolinium enhancement (LGE-%) and the LV early diastolic longitudinal strain rate (edLSR) were assessed for LV. LA conduit, booster, and reservoir functions were assessed by LA fractional volumes and strain analyses using CMR-FT. HCM patients were classified as HCM patients without LGE, with mild LGE-% (0% < LGE-% ł 10%), and prominent LGE-% (10% < LGE-%). HCM patients had worse LA functions compared with the controls (p < 0.05). The majority of LA functional indices were more impaired in HCM patients with regard to LGE. LA volumes were higher in HCM patients with prominent LGE-% compared with HCM patients with mild LGE-% (p < 0.05). However, only a minority of LA functional parameters differed between the 2 groups. LA strain parameters showed weak to modest correlations with LV LGE-% and LV edLSR. LV characteristics, to some extent, influence LA mechanics, but they might not be the only factor inducing LA dysfunction in patients with HCM.

Normal Values of left ventricular Myocardial Deformation Assessed by Cardiovascular Magnetic Resonance Feature Tracking in a Healthy Egyptian Population

Normal Values of left ventricular Myocardial Deformation Assessed by Cardiovascular Magnetic Resonance Feature Tracking in a Healthy Egyptian Population

Utility of cardiac magnetic resonance feature tracking strain assessment in chronic thromboembolic pulmonary hypertension for prediction of REVEAL 2.0 high risk status.

Chronic thromboembolic pulmonary hypertension may be cured by pulmonary endarterectomy(PEA). Thromboembolic disease distribution/PEA success primarily determines prognosis but risk scoring criteria may be adjunctive. Right ventriculoarterial (RV-PA) and ventriculoatrial (RV-right atrium [RA]) coupling may be evaluated by cardiac MRI (CMR) feature tracking deformation/strain assessment. We characterized biatrial and biventricular CMR feature tracking(FT) strain parameters following PEAand tested the ability of CMR FT to identify REVEAL 2.0 high-risk status. We undertook a retrospective single-center cross-sectional study of patients (n = 57) who underwent PEA (2015-2020). All underwent pre and postoperative catheterization and CMR. Pulmonary arterial hypertension validated risk scores were calculated. Significant postoperative improvements were observed in mean pulmonary artery pressure(mPAP) (pre-op 45 ± 11 mmHg vs. post-op 26 ± 11 mmHg; p < 0.001) and PVR however a large proportion had residual pulmonary hypertension (45%; mPAP ≥25 mmHg). PEA augmented left heart filling with left ventricular end diastolic volume index and left atrial volume index increment. Left ventricular ejection fraction was unchanged postoperatively but LV global longitudinal strain improved (pre-op median -14.2% vs. post-op -16.0%; p < 0.001). Right ventricular (RV) geometry and function also improved with reduction in RV mass. Most had uncoupled RV-PA relationships which recovered (pre-op right ventricular free wall longitudinal strain -13.2 ± 4.8%, RV stroke volume/right ventricular end systolic volume ratio 0.78 ± 0.53 vs. post-op -16.8 ± 4.2%, 1.32 ± 0.55; both p < 0.001). Postoperatively, there were sixREVEAL 2.0 high-risk patients, best predicted by impaired RA strain which was superior to traditional volumetric parameters (area under the curve [AUC] 0.99 vs.RVEF AUC 0.88). CMR deformation/strain evaluation can offer insights into coupling recovery; RA strain may be an expeditious surrogate for the more laborious REVEAL 2.0 score.

Prognostic value of feature-tracking right ventricular longitudinal strain in heart transplant recipients.

The prognostic value of cardiac magnetic resonance feature tracking (CMR-FT)-derived right ventricular longitudinal strain (RVLS) post-heart transplantation has not been studied. This study aimed to evaluate the prognostic significance of CMR-FT-derived RVLS, in patients post- heart transplantation and to directly compare its value with that of conventional RV ejection fraction (RVEF). In a cohort of consecutive heart transplantation recipients who underwent CMR for surveillance, RVLS from the free wall was measured by CMR-FT. The composite endpoint was all-cause death or major adverse cardiac events. The Cox regression model was used to examine the independent association between RVLS and the endpoint. A total of 96 heart transplantation recipients were retrospectively included. Over a median follow-up of 41 months, 20 recipients reached the composite endpoint. The multivariate Cox analysis showed that the model with RVLS (hazard ratio [HR]:1.334; 95% confidence interval [CI]:1.148 to 1.549; p < 0.001; Akaike information criterion [AIC] = 140, C-index = 0.831) was better in predicting adverse events than the model with RVEF (HR:0.928; 95% CI: 0.868 to 0.993; p = 0.030; AIC = 149, C-index = 0.751). Furthermore, receiver operating characteristic curves revealed that the accuracy for predicting adverse events was greater for RVLS than RVEF (area under the curve: 0.85 vs 0.76, p = 0.03). CMR-FT-derived RVLS is an independent predictor of adverse events in post-heart transplantation, and its predictive value was better than RVEF. Therefore, our study highlighted the importance of evaluating RVLS for risk stratification after heart transplantation. • CMR-RVLS is an independent predictor of adverse events post-heart transplantation and provides greater predictive value. • CMR-RVLS may help clinicians to risk stratification in heart transplantation recipients.

Right Ventricular Strain by Magnetic Resonance Feature Tracking Is Largely Afterload-Dependent and Does Not Reflect Contractility: Validation by Combined Volumetry and Invasive Pressure Tracings.

Cardiac magnetic resonance (CMR) is currently the gold standard for evaluating right ventricular (RV) function, which is critical in patients with pulmonary hypertension. CMR feature-tracking (FT) strain analysis has emerged as a technique to detect subtle changes. However, the dependence of RV strain on load is still a matter of debate. The aim of this study was to measure the afterload dependence of RV strain and to correlate it with surrogate markers of contractility in a cohort of patients with chronic thromboembolic pulmonary hypertension (CTEPH) under two different loading conditions before and after pulmonary endarterectomy (PEA). Between 2009 and 2022, 496 patients with 601 CMR examinations were retrospectively identified from our CTEPH cohort, and the results of 194 examinations with right heart catheterization within 24 h were available. The CMR FT strain (longitudinal (GLS) and circumferential (GCS)) was computed on steady-state free precession (SSFP) cine CMR sequences. The effective pulmonary arterial elastance (Ea) and RV chamber elastance (Ees) were approximated by dividing mean pulmonary arterial pressure by the indexed stroke volume or end-systolic volume, respectively. GLS and GCS correlated significantly with Ea and Ees/Ea in the overall cohort and individually before and after PEA. There was no general correlation with Ees; however, under high afterload, before PEA, Ees correlated significantly. The results show that RV GLS and GCS are highly afterload-dependent and reflect ventriculoarterial coupling. Ees was significantly correlated with strain only under high loading conditions, which probably reflects contractile adaptation to pulsatile load rather than contractility in general.

66 MYOCARDIAL EDEMA CONTRIBUTES TO INTERSTITIAL EXPANSION AND ASSOCIATES WITH MECHANICAL AND ELECTROCARDIOGRAPHIC CHANGES IN TAKOTSUBO SYNDROME: A CMR T1 AND T2 MAPPING STUDY

Abstract Background myocardial edema has a central role in takotsubo syndrome (TTS). Relationships between edema, mechanical and electrical abnormalities in TTS are still elusive. Methods n=32 hospitalized TTS patients and n=23 controls were analyzed. We performed cardiac magnetic resonance (CMR) with tissue mapping for the assessment of edema and interstitial expansion, global longitudinal (GLS) and circumferential strain (GCS) were evaluated by CMR feature-tracking. Twelve-lead ECGs were recorded at the time of CMR in TTS patients, aVR voltage, negative T-wave voltage and QTc length were calculated. Results mean age of the TTS cohort was 72±12-year-old, 94% women, undergoing CMR at a median of 4 days (interquartile range 2, 6) after hospital admission. Compared with controls, patients had increased LV mass (55±11 g/m2 vs 46±8 g/m2, p&amp;lt;0.001), worse left ventricular ejection fraction (LVEF), GLS and GCS (all p&amp;lt;0.001), higher septal native T1 (1116±73 msec vs 970±23 msec, p&amp;lt;0.001), T2 (56±5 msec vs 46±2 msec, p&amp;lt;0.001) and extra-cellular volume (ECV) fraction (32±5% vs 24±1%, p&amp;lt;0.001). TTS patients had higher apicobasal gradient of T2 values (12±6 msec vs 2±6 msec, p&amp;lt;0.001), basal LV wall displayed higher native T1, T2 and ECV (all p&amp;lt;0.002) but similar circumferential strain against controls (-23±3% vs -24±4%, p=0.351). In the TTS cohort, septal T2 value showed significant correlations with native T1 (r=0.609, p&amp;lt;0.001), ECV (r=0.689, p&amp;lt;0.001), LVEF (r=-0.459, p=0.008) and aVR voltage (r=-0.437, p&amp;lt;0.05). Negative T waves voltage and QTc length significantly correlated with apicobasal T2 mapping gradient (r=0.499, p=0.007 and r=0.372, p=0.047 respectively) but not with other tissue mapping measurements. Conclusions CMR T1 and T2 mapping demonstrated increased myocardial water content conditioning interstitial expansion in acute TTS. Myocardial edema was detected even outside areas of abnormal wall motion, its burden and distribution associated with mechanical and electrocardiographic changes, making it a potential prognostic marker and therapeutic target in TTS.

Comparing Cardiac Mechanics and Myocardial Fibrosis in DBD and DCD Heart Transplant Recipients

BackgroundHeart transplantation (HTx) after donation after circulatory death (DCD) is an expanding practice but is associated with increased warm ischemic time. The impact of DCD HTx on cardiac mechanics and myocardial fibrosis has not been reported. We aimed to compare cardiac mechanics and myocardial fibrosis using cardiovascular magnetic resonance (CMR) imaging in donation after brain death (DBD) and DCD HTx recipients and healthy controls. Methods and ResultsConsecutive HTx recipients between March 2015 and March 2021 who underwent routine surveillance CMR imaging were included. Cardiac mechanics were assessed using CMR feature tracking to compute global longitudinal strain, global circumferential strain, and right ventricular free-wall longitudinal myocardial strain. Fibrosis was assessed using late gadolinium enhancement imaging and estimation of extracellular volume. There were 82 (DBD n = 42, DCD n = 40) HTx recipients (aged 53 years, interquartile range 41–59 years, 24% female) who underwent CMR imaging at median of 9 months (interquartile range 6–14 months) after transplantation. HTx recipients had increased extracellular volume (29.7 ± 3.6%) compared with normal ranges (25.9%, interquartile range 25.4–26.5). Myocardial strain was impaired after transplantation compared with controls (global longitudinal strain –12.6 ± 3.1% vs –17.2 ± 1.8%, P < .0001; global circumferential strain –16.9 ± 3.1% vs –19.2 ± 2.0%, P = .002; right ventricular free-wall longitudinal strain –15.7 ± 4.5% vs –21.6 ± 4.7%, P < .0001). There were no differences in fibrosis burden (extracellular volume 30.6 ± 4.4% vs 29.2 ± 3.2%; P = .39) or cardiac mechanics (global longitudinal strain –13.1 ± 3.0% vs –12.1 ± 3.1%, P = .14; global circumferential strain –17.3 ± 2.9% vs –16.6 ± 3.1%, P = .27; right ventricular free-wall longitudinal strain –15.9 ± 4.9% vs –15.5 ± 4.1%, P = .71) between DCD and DBD HTx. ConclusionsHTx recipients have impaired cardiac mechanics compared with controls, with increased myocardial fibrosis. There were no differences in early CMR imaging characteristics between DBD and DCD heart transplants, providing further evidence that DCD and DBD HTx outcomes are comparable.

CMR feature tracking in patients with dilated cardiomyopathy: patterns of myocardial strain and focal fibrosis

BackgroundThere is a paucity of data on cardiovascular magnetic resonance feature tracking (CMR-FT) in patients with dilated cardiomyopathy (DCM). We aimed at describing global and segmental myocardial strain patterns and...

The prognostic value of the left atrial strain rate determined using cardiovascular magnetic resonance feature tracking imaging in patients with severe idiopathic dilated cardiomyopathy.

Left atrial strain rate (LASR) is rarely used as an indicator of cardiovascular disorder prognosis in dilated cardiomyopathy (DCM). In the present study, we aimed to explore the prognostic value of the LASR in patients with severe idiopathic DCM [left ventricle ejection fraction (LVEF) <35%] using cardiac magnetic resonance feature tracking (CMR-FT). A retrospective cohort study was performed. At the time of enrollment, patients who underwent cardiovascular magnetic resonance (CMR) imaging were selected for the study. Left atrium (LA) strain rate was measured in patients with severe idiopathic DCM from four-chamber and two-chamber views using a 3.0-T CMR scanner. The study endpoint was defined as a combination of all-cause death, implantable cardioverter-defibrillator (ICD), hospitalization due to cardiac failure, and heart transplantation. Cox model analyses were used to assess the statistical significance of the risk factors. Fifty-eight patients with a confirmed diagnosis of severe idiopathic DCM were ultimately included in the analysis [mean age of 46 years; 41 (73%) men]. The median follow-up was 43 months (13-72 months). Adverse cardiovascular events occurred in 29 patients: all-cause death occurred in 15 participants (25.8%), ICD was performed in 5 participants (8.6%), heart failure hospitalization occurred in 8 participants (13.8%), and 1 participant (1.7%) underwent heart transplantation. From univariate analysis, the left atrium reservoir strain rate (LASRs) [HR 0.12; 95% CI (0.02, 0.55), P=0.007] and the left atrium booster pump strain rate (LASRa) [HR 3.21; 95% CI (1.08, 9.58), P=0.036] significantly predicted the association with cardiovascular events. In model 1 after adjusting for basic cardiovascular risk factors, including age, hypertension, diabetes mellitus, and N-terminal pro-brain natriuretic peptide (NT-proBNP), the LASRs [HR 0.12, 95% CI (0.02, 0.58), P=0.009] was assessed. The mitral valve regurgitation, LA maximum volume index, and LA diastatic volume index were added in model 2 based on model 1. LASRs [HR 0.13, 95% CI (0.02. 0.82) P=0.030] was the independent prediction factor after adjustment for model 1 and model 2. The LASRs had a good prognostic value with an area under the curve of receiver operating characteristic of 0.697 (0.617, 0.777) at 1 year, 0.716 (0.643, 0.788) at 3 years, 0.716 (0.651, 0.798) at 5 years and 0.703 (0.597, 0.809) at 7 years. LA reservoir strain rate and active strain rate were powerful prognostic markers. The LASRs by MRI-FT provided independent prognostic value in patients with severe idiopathic DCM.

TRANSTHORACIC SHOCKS LEAD TO REGIONAL BI-VENTRICULAR DIASTOLIC DYSFUNCTION IN TERRITORIES WITH ACUTE MYOCARDIAL INJURY

<h3>Introduction</h3> Electric defibrillations and cardioversion are standard interventions to terminate arrhythmia. Recent evidence hints to acute post shock myocardial injury. However, that injury may follow unique pathways in every individual. Common functional measures such as ejection fraction are limited in that they represent only global ventricular function. Cardiovascular magnetic resonance feature tracking (CMR-FT) is a technique that can quantify myocardial contraction and relaxation on a regional level. The purpose of this analysis was to investigate the impact of acute myocardial injury after serial transthoracic shocks on regional systolic and diastolic myocardial deformation in a healthy animal model. <h3>Methods</h3> Ten healthy anaesthetized swine were scanned in a 3 Tesla MRI with a standard short axis cine and a clinical T1 mapping sequence in three short axis slices to detect myocardial edema. Five transthoracic shocks with 200 Joules each were applied within five minutes. Five hours post-shock the same images were re-acquired. Six control animals underwent the same protocol without shocks. Changes in regional peak strain as a measure of systolic function, and early diastolic strain rate as a measure of diastolic function were evaluated using CMR-FT analysis in circumferential orientation for both the left (LV) and right ventricle (RV). T1 maps of the LV were analyzed and reported per myocardial AHA segment as a measure of myocardial edema. For the RV, a region of interest (ROI) was contoured in each of the 3 short-axis slices. The regional changes in strain in comparison to the development of myocardial injury (ΔT1 mapping) over the course of 5h were statistically assessed using a mixed effects model accounting for the electrical intervention and multiple measurements per individual. <h3>Results</h3> Global circumferential peak strain worsened in both ventricles (LV: -15.6±3.3% to -13.0±3.6%, p<0.01; RV: -16.1±2.3% to -12.8±4.8%, p=0.03). Additionally, LV early diastolic strain rate slowed from baseline to the 5h timepoint (1.19±0.35 to 0.95±0.37/s, p = 0.02) in shocked animals. Whereas no change was observed for any global strain parameters in the control group. There was no linear association with regional LV peak strain with T1 changes (p=0.97). However, an increase in T1 was colocalized to a reduction in early diastolic strain rate (p = 0.03), where early diastolic strain rate slowed by -0.25/s every 100ms increase in T1. On the other hand, both RV systolic and diastolic function worsened in the presence of increased regional RV T1 with a change in peak strain of 2.7% and a deceleration of diastolic strain rate (–0.42/s) per 100ms increase in RV T1 (p<0.05). <h3>Conclusions</h3> Serial transthoracic shock in a healthy swine model attenuate biventricular systolic function, but it is the development of regional diastolic dysfunction that is associated with the onset of colocalized myocardial edema. Future studies are warranted to assess these effects of electrical interventions in clinical settings.

Effect of Infarct Location and Size on Left Atrial Function: A Cardiovascular Magnetic Resonance Feature Tracking Study.

Background: LA function has been recognized as a significant prognostic marker in many cardiovascular diseases. Cardiovascular magnetic resonance feature tracking (CMR-FT) represents a promising technique for left atrial function evaluation. The size and location of myocardial infarction are important factors in the cause of adverse left ventricular remodeling, but the effect on the left atriam is unclear. Purpose: to investigate the effect of location and size of previous myocardial infarction (MI) on LA function using CMR-FT. Study type: retrospective. Population: patients formerly diagnosed with anterior MI (n = 42) or non-anterior MI (n = 40) and healthy controls (n = 47). Field Strength/Sequence: a 3.0T MR, Steady state free precession (SSFP), Phase-sensitive inversion recovery (PSIR). Assessment: infarct location and size were assigned and quantified by late-gadolinium enhancement (LGE) imaging. LA performance was analyzed using CMR-FT in 2- and 4-chamber cine images, including LA reservoir, conduit and booster pump function. Statistics: descriptive statistics, ANOVA with post Bonferroni correction, Kruskal−Wallis H, Spearman’s correlation, intraclass correlation coefficient. Results: Anterior MI patients had impaired LA reservoir function (LATEF, εs, SRs), conduit function (LAPEF, εe, SRs) and booster pump function (LAAEF, εa) compared with controls (p < 0.05). Non-anterior MI patients had impaired LA strain (εs, εe, εa; p < 0.05) but preserved LAEFs (p > 0.05). After adjusting the area of MI, there was no significant difference in the LA morphology and function between the anterior and non-anterior wall groups. Stratification analysis by MI size revealed that LA volumes and LAEFs were unchanged in patients with MI size ≤ 15% compared with controls (p > 0.05); only εs and εe were decreased (p < 0.05). Increased LAVIpre-a, LAVImin and decreased LATEF, and LAAEF were found in patients with MI size > 15% compared with the MI size ≤ 15% group (p < 0.05). LVSVI, εs and MI size were significant correlated with LAVI pre-a in multiple stepwise regression analysis. Data conclusions: The location of myocardial infarction is not a major factor affecting the morphology and function of the left atrium. Patients with MI size > 15% experience more pronounced post-infarction LA remodeling and dysfunction than MI size ≤ 15% patients.

Assessment of right ventricular remodeling in chronic thromboembolic pulmonary hypertension by 2D-speckle tracking echocardiography: A comparison with cardiac magnetic resonance.

Right heart remodeling occurs in a substantial proportion of patients with chronic thromboembolic pulmonary hypertension (CTEPH) and significantly affects their prognosis. Two-dimensional speckle-tracking echocardiography (2D-STE) can be used to evaluate myocardial deformation under physiological and pathological conditions. This study aimed to assess the feasibility of 2D-STE for evaluating right ventricular (RV) remodeling in CTEPH patients. This retrospective study included 21 CTEPH patients who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR). Data for the following parameters that can reflect RV function were collected: tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), right ventricular index of myocardial performance (RIMP), peak systolic velocity of the tricuspid annulus (S'), and CMR-right ventricular ejection fraction (CMR-RVEF). The following strain parameters were calculated using post-processing software: STE-RV global longitudinal strain (STE-RVGLS), STE-RV free wall longitudinal strain (STE-RVFWLS), and CMR-RVGLS. As CMR-RVEF deteriorated, RV remodeling in CTEPH patients became more apparent and was mainly characterized by significant enlargement of the RV, weakening of myocardial deformation, and a decrease in RV contractility (RV area, STE-RVFWLS, STE-RVGLS: mild vs. severe and moderate vs. severe, p < 0.05; CMR-RVGLS: mild vs. severe, p < 0.05; TAPSE: moderate vs. severe, p < 0.05). Moreover, the Pearson correlation coefficient for correlation with CMR-derived RVEF was stronger for RVFWLS than for CMR-GLS (r-value: 0.70 vs. 0.68), and the strain values measured by 2D-STE showed a weak correlation with right heart catheterization data. Bland-Altman analysis showed good agreement between 2D-STE and CMR-feature tracking (FT) for RVGLS (bias = -0.96; 95% limit of agreement from -8.42 to 6.49). For the measurement of RVGLS, 2D-STE is similarly feasible to CMR-FT and could sensitively identify right heart remodeling.

Additive effects of mitral regurgitation on left ventricular strain in essential hypertensive patients as evaluated by cardiac magnetic resonance feature tracking.

Hypertension is one of the leading risk factors for cardiovascular disease. Mitral regurgitation (MR) is a heart valve disease commonly seen in hypertensive cases. This study aims to assess the effect of MR on left ventricle (LV) strain impairment among essential hypertensive cases and determine factors that independently impact the global peak strain of the LV. We enrolled 184 essential hypertensive patients, of which 53 were patients with MR [HTN (MR +) group] and 131 were without MR [HTN (MR-) group]. Another group of 61 age-and gender-matched controls was also included in the study. All participants had received cardiac magnetic resonance examination. The HTN (MR +) group was classified into three subsets based on regurgitation fraction, comprising mild MR (n = 22), moderate MR (n = 19), and severe MR (n = 12). We compared the LV function and strain parameters across different groups. Moreover, we performed multivariate linear regression to determine the independent factors affecting LV global radial peak strain (GRS), circumferential peak strain (GCS), and global longitudinal peak strain (GLS). HTN (MR-) cases exhibited markedly impaired GLS and peak diastolic strain rate (PDSR) but preserved LV ejection fraction (LVEF) compared to the controls. However, HTN (MR +) patients showed a decrease in LVEF and further deteriorated GRS, GCS, GLS, PDSR, and the peak systolic strain rate (PSSR) compared to the HTN (MR-) group and controls. With increasing degrees of regurgitation, the LV strain parameters were gradually reduced in HTN (MR +) patients. Even the mild MR group showed impaired GCS, GLS, PDSR, and PSSR compared to the HTN (MR-) group. Multiple regression analyses indicated that the degree of regurgitation was independently associated with GRS (β = -0.348), GCS (β = -0.339), and GLS (β = -0.344) in HTN (MR +) patients. GLS was significantly impaired in HTN (MR-) patients. MR may further exacerbate the deterioration of LV strain among essential hypertensive cases. Besides, the degree of regurgitation was independently correlated with GRS, GCS, and GLS in HTN (MR +) patients.

Impact of T2DM on right ventricular systolic dysfunction and interventricular interactions in patients with essential hypertension: evaluation using CMR tissue tracking

BackgroundPrevious studies reported that there was right ventricular (RV) systolic dysfunction in patients with hypertension. The aim of this study was to evaluate the impact of type 2 diabetes mellitus (T2DM) on RV systolic dysfunction and interventricular interactions using cardiac magnetic resonance feature tracking (CMR-FT) in patients with essential hypertension.Methods and methodsEighty-five hypertensive patients without T2DM [HTN(T2DM −)], 58 patients with T2DM [HTN(T2DM +)] and 49 normal controls were included in this study. The biventricular global radial, circumferential and longitudinal peak strains (GRS, GCS, GLS, respectively) and RV regional strains at the basal-, mid- and apical-cavity, were calculated with CMR-FT and compared among controls and different patient groups. Backward stepwise multivariable linear regression analyses were used to determine the effects of T2DM and left ventricular (LV) strains on RV strains.ResultsThe biventricular GLS and RV apical longitudinal strain deteriorated significantly from controls, through HTN(T2DM-), to HTN(T2DM +) groups. RV middle longitudinal strain in patient groups were significantly reduced, and LV GRS and GCS and RV basal longitudinal strain were decreased in HTN(T2DM +) but preserved in HTN(T2DM-) group. Multivariable regression analyses adjusted for covariates demonstrated that T2DM was independently associated with LV strains (LV GRS: β = − 4.278, p = 0.004, model R2 = 0.285; GCS: β = 1.498, p = 0.006, model R2 = 0.363; GLS: β = 1.133, p = 0.007, model R2 = 0.372) and RV GLS (β = 1.454, p = 0.003, model R2 = 0.142) in hypertension. When T2DM and LV GLS were included in the multiple regression analysis, both T2DM and LV GLS (β = 0.977 and 0.362, p = 0.039 and < 0.001, model R2 = 0.224) were independently associated with RV GLS.ConclusionsT2DM exacerbates RV systolic dysfunction in patients with hypertension, which may be associated with superimposed LV dysfunction by coexisting T2DM and suggests adverse interventricular interactions.

Abstract 15106: Impaired Regional Strain by Cardiovascular Magnetic Resonance Feature-Tracking Predicts Low Sensing Value After Cardiac Defibrillator Implantation in Patients With Arrhythmogenic Cardiomyopathy

Introduction: Inadequate ventricular sensing at implantable cardiac defibrillator (ICD) implantation in patients with arrhythmogenic cardiomyopathy (ACM) is troubling and might cause inappropriate ICD interventions and complications. We aimed to evaluate the value of ventricular mechanics features in predicting low sensing value by emerging cardiovascular magnetic resonance-feature tracking (CMR-FT) in ACM patients. Hypothesis: CMR-FT characteristics prior to ICD implantation might assist in predicting low R wave amplitude. Methods: We retrospectively enrolled ACM patients receiving CMR examinations prior to ICD implantation at our center from January 2011 to July 2021. The strain parameters of LV and RV were analyzed by CMR-FT. The R wave amplitude (RWA) was obtained within 24 hours of completion of the ICD implantation and its association with CMR strain parameters was analyzed. Results: We enrolled 83 ACM patients with a median RWA of 8.0 mV (Interquartile range IQR:5.4-12.1 mV) and impedance within the normal range. 18 (21.7%) patients were found with low RWA (&lt;5mV) despite attempts in over 5 positions. RV strain parameters including RV global longitudinal, circumferential and radial strain rather than LV strain parameters correlated significantly with RWA (Spearman’s correlation coefficients: GLS: -0.35, GCS: -0.58, GRS: 0.59, all P&lt;0.01). RVGRS and RVGCS were found not only associated with RWA after adjusting for clinical cofounders (coefficients: RVGCS: -0.53, RVGRS:0.32, p&lt;0.01) but also valuable in predicting low RWA (areas under the curve: 0.76 and 0.73 respectively; sensitivity: both 0.72, specificity: both 0.71). Conclusions: Low sensing of ICD lead in ACM patients was associated with impaired RV mechanics. RVGCS and RVGRS by CMR-FT were valuable parameters for predicting low RWA and might assist operation planning.

Abstract 14076: Myocardial Tissue Characterization and Strain by Cardiac Magnetic Resonance and Their Relationship in Pediatric Patients With Acute Myocarditis Within 2 Weeks of Presentation

Introduction: Cardiac magnetic resonance (CMR) provides rich data on myocardial function, including indices such as strain, as well as tissue characterization. There is no published data on these values within 2 weeks of the diagnosis of myocarditis. We sought to describe these findings in children with acute myocarditis who underwent CMR early after presentation and determine relationships between these values. Methods: We retrospectively reviewed the clinical and imaging data of patients &lt;21 years clinically diagnosed with acute myocarditis and underwent CMR within 14 days of presentation. Those who suffered cardiac arrest or with autoimmune disease, known cardiomyopathy or congenital heart disease were excluded. Strain was measured using CMR feature tracking. Spearman’s correlation was utilized. Significance was P &lt;0.05. Results: 85 patients underwent CMR at a median of 2 days following presentation (IQR 2 - 4) with median age 16.3 years (IQR 14.3, 17.5). Tissue characteristics, ventricular function and strain are listed in Table 1. 77 studies (90.6%) met Lake Louise criteria for myocarditis and 66 (77.7%) showed late gadolinium enhancement. Global circumferential (GCS) and longitudinal strain correlated with T2 values, biventricular ejection fractions, and peak brain natriuretic peptide (BNP); GCS also correlated with T1 values (Table 1, Figure 1). Conclusions: We present the first data on early strain and tissue characterization for myocarditis. Both global longitudinal and circumferential strain correlated with tissue characteristics and serum measures of acute injury. Strain imaging may be a sensitive marker of myocardial injury in patients with myocarditis.