Quantification of left atrial function in patients with non-obstructive hypertrophic cardiomyopathy by cardiovascular magnetic resonance feature tracking imaging: a feasibility and reproducibility study

Cardiac Magnetic Resonance Left Atrial Strain in the Prediction of Death, Ischemic Stroke, and Heart Failure

BACKGROUND

To determine the prognostic value of left atrial strain (LAS) using cardiac magnetic resonance for predicting death, heart failure, and ischemic stroke in patients with known or suspected coronary artery disease with preserved left ventricular systolic function and no prior history of ischemic stroke, heart failure, or atrial fibrillation.

METHODS AND RESULTS

This retrospective cohort analysis included patients referred for stress cardiac magnetic resonance or myocardial viability studies between September 2017 and December 2019. Patients with impaired left ventricular systolic function (<50%) or a history of atrial fibrillation, stroke, or heart failure were excluded. A multivariable Cox model assessed the prognostic value of LAS, with the primary outcomes being the composite outcomes of all-cause death, ischemic stroke, and heart failure. A total of 2030 participants were included in the study. The average LAS was 24.1±8.5%; 928 had LAS <23%, and 1102 had LAS ≥23%. The mean follow-up duration was 39.9±13.6 months. There were 49 deaths (2.4%), 32 ischemic strokes (1.6%), and 34 heart failure events (1.7%). Patients with LAS <23% were at greater risk for composite outcome, with an adjusted hazard ratio of 2.31 (95% CI, 1.50-3.55).

CONCLUSIONS

LAS by cardiac magnetic resonance has an independent and incremental prognostic value for death, ischemic stroke, and heart failure in patients with preserved left ventricular systolic function. This prognostic value is observed after adjusting for clinical and cardiac magnetic resonance parameters, including left ventricular systolic function, late gadolinium enhancement, and left atrial volume index.

Myocardial Strain Measured by Cardiac Magnetic Resonance Predicts Cardiovascular Morbidity and Death

BACKGROUND

Myocardial strain using cardiac magnetic resonance (CMR) is a sensitive marker for predicting adverse outcomes in many cardiac disease states, but the prognostic value in the general population has not been studied conclusively.

OBJECTIVES

The goal of this study was to assess the independent prognostic value of CMR feature tracking (FT)-derived LV global longitudinal (GLS), circumferential (GCS), and radial strain (GRS) metrics in predicting adverse outcomes (heart failure, myocardial infarction, stroke, and death).

METHODS

Participants from the UK Biobank population imaging study were included. Univariable and multivariable Cox models were used for each outcome and each strain marker (GLS, GCS, GRS) separately. The multivariable models were tested with adjustment for prognostically important clinical features and conventional global LV imaging markers relevant for each outcome.

RESULTS

Overall, 45,700 participants were included in the study (average age 65 ± 8 years), with a median follow-up period of 3 years. All univariable and multivariable models demonstrated that lower absolute GLS, GCS, and GRS were associated with increased incidence of heart failure, myocardial infarction, stroke, and death. All strain markers were independent predictors (incrementally above some respective conventional LV imaging markers) for the morbidity outcomes, but only GLS predicted death independently: (HR: 1.18; 95% CI: 1.07-1.30).

CONCLUSIONS

In the general population, LV strain metrics derived using CMR-FT in radial, circumferential, and longitudinal directions are strongly and independently predictive of heart failure, myocardial infarction, and stroke, but only GLS is independently predictive of death in an adult population cohort.

The impact of diabetes mellitus on cardiac function assessed by magnetic resonance imaging in patients with hypertrophic cardiomyopathy

BACKGROUND

The adverse prognostic impact of diabetes on hypertrophic cardiomyopathy (HCM) is poorly understood. We sought to explore the underlying mechanisms in terms of structural and functional remodelling in HCM patients with coexisting diabetes (HCM-DM).

METHODS

A total of 45 HCM-DM patients were retrospectively included. Isolated HCM controls (HCM patients without diabetes) were matched to HCM-DM patients in terms of maximal wall thickness, age, and gender distribution. Left ventricular (LV) and atrial (LA) performance were evaluated using cardiac magnetic resonance feature tracking strain analyses. The associations between diabetes and LV/LA impairment were investigated by univariable and multivariable linear regression.

RESULTS

Compared with the isolated HCM controls, the HCM-DM patients had smaller end-diastolic volume and stroke volume, lower ejection fraction, larger mass/volume ratio and impaired strains in all three directions (all P < 0.05). In terms of the LA parameters, HCM-DM patients presented impaired LA reservoir and conduit strain/strain rate (all P < 0.05). Among all HCM patients, comorbidity with diabetes was independently associated with a low LV ejection fraction (β = - 6.05, P < 0.001) and impaired global longitudinal strain (β = 1.40, P = 0.007). Moreover, compared with the isolated HCM controls, HCM-DM patients presented with more myocardial fibrosis according to late gadolinium enhancement, which was an independent predictor of impaired LV global radial strain (β = - 45.81, P = 0.008), LV global circumferential strain (β = 18.25, P = 0.003), LA reservoir strain (β = - 59.20, P < 0.001) and strain rate (β = - 2.90, P = 0.002).

CONCLUSIONS

Diabetes has adverse effects on LV and LA function in HCM patients, which may be important contributors to severe manifestations and outcomes in those patients. The present study strengthened the evidence of the prevention and management of diabetes in HCM patients.

"Interstitial fibrosis is associated with left atrial remodeling and adverse clinical outcomes in selected low-risk patients with hypertrophic cardiomyopathy"

BACKGROUND

Cardiovascular magnetic resonance (CMR) extracellular volume (ECV) allows non-invasive detection of myocardial interstitial fibrosis, which may be related to diastolic dysfunction and left atrial (LA) remodeling in hypertrophic cardiomyopathy (HCM). While the prognostic role of LGE is well-established, interstitial fibrosis and LA dysfunction are emerging novel markers in HCM. This study aimed to explore the interaction between interstitial fibrosis by ECV, LA morpho-functional parameters and adverse clinical outcomes in selected low-risk patients with HCM.

METHODS

115 HCM patients and 61 matched controls underwent CMR to identify: i) interstitial fibrosis by ECV in hypertrophied left ventricular LGE-negative remote myocardium (r-ECV); ii) LA indexed maximum (LAVi max) and minimum (LAVi min) volumes, ejection fraction (LA-EF) and strain (reservoir εs, conduit εe and booster εa), by CMR feature-tracking. 2D-echocardiographic assessment of diastolic function was also performed within 6 months from CMR. A composite endpoint including worsening NYHA class, heart failure hospitalization, atrial fibrillation and all-cause death was evaluated at 2.3 years follow-up. HCM patients were divided into two groups, according to r-ECV values of controls.

RESULTS

Patients with r-ECV ≥29% (n = 45) showed larger LA volumes (LAVimax 63 vs. 54 ml/m2, p < 0.001; LAVimin 43 vs. 28 ml/m2, p 〈0001), worse LA function (εs 16 vs. 28%, εe 8 vs. 15%, εa 8 vs. 14%, LA-EF 33 vs. 49%, all p < 0.001) and elevated Nt-proBNP (1115 vs. 382 pg/ml, p = 0.002). LA functional parameters inversely correlated with r-ECV (εs r = -0.54; LA-EF r = -0.46; all p < 0.001) and E/e' (εs r = -0.52, LA-EF r = -0.46; all p < 0.006). r-ECV ≥29% and LAVi min >30 ml/m2 have been identified as possible independent factors associated with the endpoint.

CONCLUSIONS

In HCM diffuse interstitial fibrosis detected by increased r-ECV is associated with LA remodeling and emerged as a potential independent predictor of adverse clinical outcomes, on top of the well-known prognostic impact of LGE.

Quantification of left atrial strain in patients with idiopathic inflammatory myopathy using cardiovascular magnetic resonance feature tracking

BACKGROUND

Left atrial (LA) dysfunction is involved in idiopathic inflammatory myopathy (IIM). Multiparametric cardiovascular magnetic resonance (CMR) strain imaging is a feasible and reproducible tool for examining global and regional LA functions, as well as left ventricular (LV) function in IIM patients.

AIM

The aim of this study was to evaluate the feasibility and reproducibility of LA strain occurrence and strain rate for LA function assessment using CMR in IIM cases.

MATERIALS AND METHODS

A total of 36 IIM and 42 healthy control cases were included. Baseline ventricular function was comparatively assessed in both groups. LA strain occurrence and strain rate were examined by cine cardiac magnetic resonance imaging [MRI] utilizing an in-house semiautomated technique. LA global function indexes were quantitated, including reservoir, conduit, and booster-pump functions.

RESULTS

A total of 78 participants were enrolled in this study. There was no significant difference in left/right ventricular routine functions between IIM patients and control individuals (p>0.05); the same results (p>0.05) was also observed between patients with high hs-cTnI and normal. However, LV mass index had significant difference (p1=0.003, p2<0.01). Compared with IIM patients and control individuals, only total strain (εs) (p4=0.046) and passive strain (εe) (p4=0.002) showed significant difference, and in cases with high hs-cTnI and normal hs-cTnI, there are differences for εs (p3=0.012) and εe (p4=0.047). The strongest association was found between εe and LV ejection fraction (LVEF) (r=0.581, p<0.01).

CONCLUSION

IIM cases have altered LA reservoir and conduit functions, and LA strain could reflect LA function.

CMR-based cardiac phenotyping in different forms of heart failure

Heart failure (HF) is a heterogenous disease requiring precise diagnostics and knowledge of pathophysiological processes. Since structural and functional imaging data are scarce we hypothesized that cardiac magnetic resonance (CMR)-based analyses would provide accurate characterization and mechanistic insights into different HF groups comprising preserved (HFpEF), mid-range (HFmrEF) and reduced ejection fraction (HFrEF). 22 HFpEF, 17 HFmrEF and 15 HFrEF patients as well as 19 healthy volunteers were included. CMR image assessment contained left atrial (LA) and left ventricular (LV) volumetric evaluation as well as left atrioventricular coupling index (LACI). Furthermore, CMR feature-tracking included LV and LA strain in terms of reservoir (Es), conduit (Ee) and active boosterpump (Ea) function. CMR-based tissue characterization comprised T1 mapping as well as late-gadolinium enhancement (LGE) analyses. HFpEF patients showed predominant atrial impairment (Es 20.8%vs.25.4%, p = 0.02 and Ee 8.3%vs.13.5%, p = 0.001) and increased LACI compared to healthy controls (14.5%vs.23.3%, p = 0.004). Patients with HFmrEF showed LV enlargement but mostly preserved LA function with a compensatory increase in LA boosterpump (LA Ea: 15.0%, p = 0.049). In HFrEF LA and LV functional impairment was documented (Es: 14.2%, Ee: 5.4% p < 0.001 respectively; Ea: 8.8%, p = 0.02). This was paralleled by non-invasively assessed progressive fibrosis (T1 mapping and LGE; HFrEF > HFmrEF > HFpEF). CMR-imaging reveals insights into HF phenotypes with mainly atrial affection in HFpEF, ventricular affection with atrial compensation in HFmrEF and global impairment in HFrEF paralleled by progressive LV fibrosis. These data suggest a necessity for a personalized HF management based on imaging findings for future optimized patient management.

Left Atrial Dysfunction in Apical Hypertrophic Cardiomyopathy: Assessed by Cardiovascular Magnetic Resonance Feature-tracking

PURPOSE

To evaluate the left atrial (LA) function in participants with apical hypertrophic cardiomyopathy (AHCM) by cardiovascular magnetic resonance feature tracking (CMR-FT).

MATERIALS AND METHODS

Thirty typical AHCM (TAHCM) patients, 23 subclinical AHCM (SAHCM) patients and 32 normal healthy volunteers who underwent CMR exam were retrospectively analyzed. LA reservoir, conduit, and contractile function were quantified by volumetric and CMR-FT derived strain and strain rate (SR) parameters from 2-chamber and 4-chamber cine imaging.

RESULTS

Compared with healthy participants, both TAHCM and SAHCM patients had impaired LA reservoir function (total strain [%]: TAHCM 31.3±12.2, SAHCM 31.8±12.3, controls 40.4±10.7, P <0.01; total SR [/s]: TAHCM 1.1±0.4, SAHCM 1.1±0.5, controls 1.4 ± 0.4, P <0.01) and conduit function (passive strain [%]: TAHCM 14.4±7.6, SAHCM 16.4±8.8, controls 23.3±8.1, P <0.01; passive SR [/s]: TAHCM -0.5±0.3, SAHCM -0.6±0.3, controls -1.0±0.4, P <0.01). Regarding contraction function, although TAHCM and SAHCM patients had preserved active emptying fraction and strain (all P >0.05), patients with TAHCM had the lowest active SR value among the 3 groups ( P= 0.03). LA reservoir and conduit strain were both significantly associated with left ventricular mass index and maximal wall thickness (all P <0.05). A moderate correlation between LA passive SR and left ventricular cardiac index ( P <0.01).

CONCLUSIONS

The LA reservoir and conduit function are predominately impaired and appeared in both SAHCM and TAHCM patients.

Effect of Metabolic Syndrome on Left Atrial and Left Ventricular Deformation and Atrioventricular Interactions in Patients With Myocardial Infarction

BACKGROUND

Metabolic syndrome (MetS) is associated with worse prognosis in patients with myocardial infarction (MI). However, it is unclear how MetS in MI patients is associated with left atrial (LA) and left ventricular (LV) deformation.

PURPOSE

To determine the effect of MetS on LA and LV deformation and atrioventricular interactions in MI patients.

STUDY TYPE

Retrospective.

POPULATION

One hundred eighty-one MI patients (73 MetS+ and 108 MetS-), 107 age- and sex-matched controls (49 MetS+ and 58 MetS-).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession (SSFP)/segmented phase-sensitive inversion recovery SSFP sequence.

ASSESSMENT

LA strain and strain rates (reservoir, conduit, and active), left atrioventricular coupling index (LACI), and LV geometry and radial, circumferential and longitudinal global peak strains (PS) were compared among groups.

STATISTICAL TESTS

Two-way analysis of variance, Spearman and Pearson's correlation coefficients, and multivariable linear regression analysis. P value <0.05 indicated statistical significance.

RESULTS

Compared with controls, the MI patients with or without MetS showed impaired LA function (reservoir, conduit, and active) and LV deformation (radial, circumferential, and longitudinal PS) and higher LACI. The MetS+ group had lower LA reservoir and conduit function and LV deformation than MetS- group. The MetS-MI interaction was not statistically significant. Furthermore, multivariable linear regression showed that MetS was independently associated with LA and LV deformation (β = -0.181 to -0.209) in MI patients; LA function was independently associated with LV circumferential PS (β = 0.230 to 0.394) and longitudinal PS (β = 0.189 to 0.420), and LA passive strain and strain rate were negatively associated with LV mass (β = -0.178 and -0.298).

DATA CONCLUSION

MetS may be associated with the LA and LV dysfunction in MI patients. Impaired LV deformation and LV hypertrophy are independently associated with LA dysfunction in MI patients, and the MI patients have higher LACI than controls, suggesting atrioventricular interaction alterations.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: 3.

Application of left atrial strain derived from cardiac magnetic resonance feature tracking to predict cardiovascular disease: A comprehensive review

The structural and functional changes of the left atrium (LA)are important for maintaining the filling of the left ventricle (LV), whether the hemodynamics is stable or not, and are valuable for evaluating LV diastolic dysfunction and grading the severity. Studies over the past decade have shown that LA structural alterations are linked to several cardiovascular disorders, and LA enlargement has been identified as a strong predictor of several cardiovascular diseases. However, LA structural or volumetric abnormalities are commonly seen in the advanced stages of disease and do not adequately represent functional changes throughout the cardiac cycle. In recent years, LA strain obtained using cardiac magnetic resonance feature tracking (CMR-FT)technology has been shown to provide early monitoring of LA tension damage while also comprehensively reflecting LA functional changes in three phases, providing deeper insights into cardiovascular disease risk, prognosis of cardiovascular disease, and evaluation of therapeutic efficacy. When compared to the ultrasound speckle tracking approach, the CMR-FT technique provides improved spatial resolution, repeatability, and reproducibility. We report a comprehensive review of the most recent studies on CMR-LA strain in the past five years, including normal reference values, early detection of disease, incremental diagnosis, improvement of risk stratification, assessment of the value of atrial-ventricular hemodynamics and coupled injury, major adverse cardiovascular events and prognostic value, as well as future research perspectives and current limitations, aiming at providing an objective reference for the further exploration of the value of the application of CMR-LA strain in various cardiac disorders.

Automated assessment of cardiac pathologies on cardiac MRI using T1-mapping and late gadolinium phase sensitive inversion recovery sequences with deep learning

BACKGROUND

A deep learning (DL) model that automatically detects cardiac pathologies on cardiac MRI may help streamline the diagnostic workflow. To develop a DL model to detect cardiac pathologies on cardiac MRI T1-mapping and late gadolinium phase sensitive inversion recovery (PSIR) sequences were used.

METHODS

Subjects in this study were either diagnosed with cardiac pathology (n = 137) including acute and chronic myocardial infarction, myocarditis, dilated cardiomyopathy, and hypertrophic cardiomyopathy or classified as normal (n = 63). Cardiac MR imaging included T1-mapping and PSIR sequences. Subjects were split 65/15/20% for training, validation, and hold-out testing. The DL models were based on an ImageNet pretrained DenseNet-161 and implemented using PyTorch and fastai. Data augmentation with random rotation and mixup was applied. Categorical cross entropy was used as the loss function with a cyclic learning rate (1e-3). DL models for both sequences were developed separately using similar training parameters. The final model was chosen based on its performance on the validation set. Gradient-weighted class activation maps (Grad-CAMs) visualized the decision-making process of the DL model.

RESULTS

The DL model achieved a sensitivity, specificity, and accuracy of 100%, 38%, and 88% on PSIR images and 78%, 54%, and 70% on T1-mapping images. Grad-CAMs demonstrated that the DL model focused its attention on myocardium and cardiac pathology when evaluating MR images.

CONCLUSIONS

The developed DL models were able to reliably detect cardiac pathologies on cardiac MR images. The diagnostic performance of T1 mapping alone is particularly of note since it does not require a contrast agent and can be acquired quickly.

Unrecognized myocardial scar by late-gadolinium-enhancement cardiovascular magnetic resonance: Insights from the population-based Hamburg City Health Study

BACKGROUND

The presence of myocardial scar is associated with poor prognosis in several underlying diseases. Late-gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging reveals clinically silent "unrecognized myocardial scar" (UMS), but the etiology of UMS often remains unclear. This population-based CMR study evaluated prevalence, localization, patterns, and risk factors of UMS.

METHODS

The study population consisted of 1064 consecutive Hamburg City Health Study participants without a history of coronary heart disease or myocarditis. UMS was assessed by standard-phase-sensitive-inversion-recovery LGE CMR.

RESULTS

Median age was 66 [quartiles 59, 71] years and 37% (388/1064) were females. UMS was detected in 244 (23%) participants. Twenty-five participants (10%) had ischemic, and 217 participants (89%) had non-ischemic scar patterns, predominantly involving the basal inferolateral left-ventricular (LV) myocardium (75%). Two participants (1%) had coincident ischemic and non-ischemic scar. The presence of any UMS was independently associated with LV ejection fraction (odds ratios (OR) per standard deviation (SD) 0.77 (confidence interval (CI) 0.65-0.90), p = 0.002) and LV mass (OR per SD 1.54 (CI 1.31-1.82), p < 0.001). Ischemic UMS was independently associated with LV ejection fraction (OR per SD 0.58 (CI 0.39-0.86), p = 0.007), LV mass (OR per SD 1.74 (CI 1.25-2.45), p = 0.001), and diabetes (OR 4.91 (CI 1.66-13.03), p = 0.002). Non-ischemic UMS was only independently associated with LV mass (OR per SD 1.44 (CI 1.24-1.69), p < 0.001).

CONCLUSION

UMS, in particular with a non-ischemic pattern, is frequent in individuals without known cardiac disease and predominantly involves the basal inferolateral LV myocardium. Presence of UMS is independently associated with a lower LVEF, a higher LV mass, and a history of diabetes.

Cardiac magnetic resonance analysis of left atrium function in patients with pre-apical hypertrophic cardiomyopathy

Background

Patients presenting with unexplained T wave inversion on electrocardiogram combined with thickened left ventricular apex but less than 15 mm had been proposed as a preclinical scope of apical hypertrophy cardiomyopathy (pre-ApHCM). However, analysis of left atrial (LA) function in these patients has not been studied. This study aims to evaluate the LA function in pre-ApHCM patients and compare it with patients with ApHCM using cardiac magnetic resonance (CMR) imaging.

Methods

In this retrospective case-control study, a total of 3,593 CMR reports from Beijing Anzhen Hospital, Capital Medical University, China were reviewed. Finally, 31 pre-ApHCM patients were identified and 40 ApHCM and 31 normal controls were included for comparison. LA volumetric and strain were analyzed by CMR. Two-tailed one-way ANOVA was used to analyze the difference of three groups. Pearson correlation test was used for correlation analysis.

Results

All of the volumetric parameters in pre-ApHCM group were higher than those in control group. LA reservoir (LA total EF, εs) and conduit function (LA passive EF, εe) parameters, were significantly different among the three groups, which were the lowest in the ApHCM group, intermediate in the pre-ApHCM group, and the highest in the control group ((all P<0.001). Compared with the control group, the LA booster pump function, both the booster EF and booster pump strain (εa) in ApHCM were impaired (P=0.003 and P=0.002 respectively). Meanwhile, only the εa was impaired (P=0.016) while LA booster EF was not (P=0.064) in the pre-ApHCM group, neither εa nor the booster EF show difference between the ApHCM and pre-ApHCM (P=0.272 and P=0.518 respectively).

Conclusions

LA function features in pre-ApHCM patients were similar to ApHCM but different from the normal controls. In pre-ApHCM and ApHCM patients, LA reservoir and conduit function impaired earlier before left atrium enlarged and decreased progressively as apex thickens. These findings may help to understand the LA functional change from pre-ApHCM to ApHCM, and to detect subclinical changes in patients with pre-ApHCM before overt hypertrophy or clinical symptoms develop.

Left atrial strain analysis in the realm of pediatric cardiology: Advantages and implications

BACKGROUND

Left atrial (LA) strain analysis has emerged as a noninvasive technique for assessing LA function and early detection of myocardial deformation. Recently, its application has also shown promise in the pediatric population, spanning diverse cardiac conditions that demand accurate and sensitive diagnostic measures.

OBJECTIVE

This research article endeavors to explore the role of LA strain parameters and contribute to the growing body of knowledge in pediatric cardiology, paving the way for more effective and tailored approaches to patient care.

METHODS

A comprehensive literature review was conducted to gather evidence from studies using echocardiographic strain imaging techniques across pediatric populations.

RESULTS

LA strain parameters exhibited greater sensitivity than conventional atrial function indicators, with early detection of diastolic dysfunction and LA remodeling in pediatric cardiomyopathy, children with multisystem inflammatory syndrome, rheumatic heart disease, as well as childhood renal insufficiency and obesity offering prognostic relevance as potential markers in these pediatric subpopulations. However, there remains a paucity of evidence concerning pediatric mitral valve pathology, justifying further exploration.

CONCLUSION

LA strain analysis carries crucial clinical and prognostic implications in pediatric cardiac conditions, with reliable accuracy and sensitivity to early functional changes.

Temporal Uncertainty Localization to Enable Human-in-the-loop Analysis of Dynamic Contrast-enhanced Cardiac MRI Datasets

Dynamic contrast-enhanced (DCE) cardiac magnetic resonance imaging (CMRI) is a widely used modality for diagnosing myocardial blood flow (perfusion) abnormalities. During a typical free-breathing DCE-CMRI scan, close to 300 time-resolved images of myocardial perfusion are acquired at various contrast "wash in/out" phases. Manual segmentation of myocardial contours in each time-frame of a DCE image series can be tedious and time-consuming, particularly when non-rigid motion correction has failed or is unavailable. While deep neural networks (DNNs) have shown promise for analyzing DCE-CMRI datasets, a "dynamic quality control" (dQC) technique for reliably detecting failed segmentations is lacking. Here we propose a new space-time uncertainty metric as a dQC tool for DNN-based segmentation of free-breathing DCE-CMRI datasets by validating the proposed metric on an external dataset and establishing a human-in-the-loop framework to improve the segmentation results. In the proposed approach, we referred the top 10% most uncertain segmentations as detected by our dQC tool to the human expert for refinement. This approach resulted in a significant increase in the Dice score ( p < 0.001 ) and a notable decrease in the number of images with failed segmentation (16.2% to 11.3%) whereas the alternative approach of randomly selecting the same number of segmentations for human referral did not achieve any significant improvement. Our results suggest that the proposed dQC framework has the potential to accurately identify poor-quality segmentations and may enable efficient DNN-based analysis of DCE-CMRI in a human-in-the-loop pipeline for clinical interpretation and reporting of dynamic CMRI datasets.

Ventricular-atrial coupling in subjects with normal, preserved, and reduced left ventricular ejection fraction: insights from cardiac magnetic resonance imaging

OBJECTIVES

To assess the correlation between LA and LV strain measurements in different clinical scenarios and evaluate to what extent LA deformation contributes to the prognosis of patients.

METHODS

A total of 297 consecutive participants including 75 healthy individuals, 75 hypertrophic cardiomyopathy (HCM) patients, 74 idiopathic dilated cardiomyopathy (DCM), and 73 chronic myocardial infarction (MI) patients were retrospectively enrolled in this study. The associations of LA-LV coupling with clinical status were statistically analyzed by correlation, multiple linear regression, and logistic regression. Survival estimates were calculated by receiver operating characteristic analyses and Cox regression analyses.

RESULTS

Overall, moderate correlations were found between LA and LV strain in every phase of the cardiac cycle (r: -0.598 to -0.580, all p < 0.001). The slope of the regression line of the individual strain-strain curve had a significant difference among 4 groups (-1.4 ± 0.3 in controls, -1.1 ± 0.6 in HCM, -1.8 ± 0.8 in idiopathic DCM, -2.4 ± 1.1 in chronic MI, all p < 0.05). During a median follow-up of 4.7 years, the total LA emptying fraction was independently associated with primary (hazard ratio: 0.968, 95% CI: 0.951-0.985) and secondary endpoints (hazard ratio: 0.957, 95% CI: 0.930-0.985) with an area under the curve (AUC) of 0.720 respectively, 0.806, which was significantly higher than the AUC of LV parameters.

CONCLUSIONS

The coupled correlations between the left atria and ventricle in every phase and the individual strain-strain curve vary with etiology. LA deformation in late diastole provides prior and incremental information on cardiac dysfunction based on LV metrics. The total LA emptying fraction was an independent indicator for clinical outcome superior to that of LV typical predictors.

CLINICAL RELEVANCE STATEMENT

Left ventricular-atrial coupling is not only valuable for comprehending the pathophysiological mechanisms of cardiovascular diseases caused by different etiologies but also holds significant importance for the prevention of adverse cardiovascular events and targeted treatment.

KEY POINTS

• In HCM patients with preserved LVEF, LA deformation is a sensitive indicator for cardiac dysfunction prior to LV parameters with a reduced LA/LV strain ratio. • In patients with reduced LVEF, LV deformation impairment is more consequential than that of the LA with an increased LA/LV strain ratio. Furthermore, impaired LA active strain indicates potential atrial myopathy. • Among LA and LV parameters, the total LA emptying fraction is the best predictor for guiding clinical management and follow-up in patients with different statuses of LVEF.

Asymmetric remodeling between the left and right atria in patients with advanced interatrial block and atrial fibrillation

BACKGROUND

Advanced interatrial block (A-IAB) on electrocardiography (ECG) represents the conduction delay between the left and right atria. We investigated the association of A-IAB with left and right atrial (LA/RA) remodeling in patients with atrial fibrillation (AF).

METHODS

We enrolled 74 patients who underwent ECG, cardiac computed tomography (CCT), and echocardiography during sinus rhythm before catheter ablation of AF. A-IAB was defined as P-wave duration ≥120 ms with a biphasic morphology in leads III and aVF or notched morphology in lead II. We compared the maximum and minimum LA/RA volume indices (max and min LAV/RAVI), LA/RA expansion index (LAEI/RAEI), and total, passive, and active LA/RA emptying fraction (LAEF/RAEF) between patients with and without A-IAB.

RESULTS

Of the 74 patients (mean age, 64.3 ± 9.6 years), 35 (47%) showed A-IAB. Patients with A-IAB had a significantly higher likelihood of hypertension and left ventricular diastolic dysfunction than those without. Patients with A-IAB had significantly larger max (69.2 [60.7-79.7]mL/m2 vs. 60.9 [50.4-68.3]mL/m2, P < 0.01) and min (44.0 [37.2-52.1]mL/m2 vs. 34.1 [29.2-43.5]mL/m2, P < 0.01) LAVI than those without. The max and min RAVI were not significantly different between groups. LAEI (55.1 [48.2-78.5]% vs. 72.1 [57.8-84.8]%, P < 0.05), total LAEF (35.5 [32.5-44.0]% vs. 41.9 [36.6-45.9]%, P < 0.05), and passive LAEF (12.2 [10.0-14.4]% vs. 15.5 [11.2-19.6]%, P < 0.05) were significantly lower in patients with A-IAB than without.

CONCLUSIONS

A-IAB was associated with LA, but not RA enlargement, in patients with AF. A-IAB may indicate LA functional remodeling in the reservoir and conduit phases.

The correlation of left atrial dysfunction and amyloid load in patients with immunoglobulin light-chain cardiac amyloidosis: a 3T cardiac magnetic resonance study

OBJECTIVE

To investigate the left atrial (LA) changes in immunoglobulin light-chain cardiac amyloidosis (AL-CA) patients with different risk stratifications and to explore the correlation between LA function and the degree of amyloid load using cardiac magnetic resonance (CMR) imaging.

METHODS

Forty-three AL-CA patients were retrospectively enrolled and were divided into low-to-moderate-risk group (n = 16, increased NT-proBNP or troponin I, or both normal) and high-risk group (n = 27, increased NT-proBNP and troponin I). 20 healthy individuals matched for age and gender were included. The function, myocardial deformation of left heart, and left ventricular (LV) tissue characterization among the three groups were compared. The correlation between LA function and LV tissue characterization was investigated.

RESULTS

Compared with the controls, the AL-CA patients had a larger LA volume, lower left atrial emptying fraction (LAEF) and impaired left atrial strain (LAS). The high-risk group exhibited lower reservoir and booster function and increased LV extracellular volume (LV-ECV) than the low-to-moderate-risk group (p < 0.05). LV-ECV was significantly correlated with LAS and LAEF (all p < 0.05) but not LAEFconduit. The LAS and LAEF had a good diagnostic ability for risk stratification of AL-CA patients (area under the curve, 0.70 ~ 0.72).

CONCLUSION

High-risk AL-CA patients showed more severe LA function impairment than low-to-moderate-risk AL-CA patients. LAS and LAEF were closely associated with LV-ECV in AL-CA patients, LAS and LAEF exhibited good capability to differentiate AL-CA patients of different risk stratifications.

ADVANCES IN KNOWLEDGE

CMR-derived LAS and LAEF were correlated with amyloid load, allowing for differentiation of AL-CA patients at different risk stages.

Different phenotype of left atrial function impairment in patients with hypertrophic cardiomyopathy and hypertension: comparison of healthy controls

Background

The impairment of atrial function and atrial-ventricular coupling in diseases with left ventricular (LV) hypertrophy has been increasingly recognized. This study compares left atrium (LA) and right atrium (RA) function, as well as LA-LV coupling, in patients with hypertrophic cardiomyopathy (HCM) and hypertension (HTN) with preserved LV ejection fraction (EF), using cardiovascular magnetic resonance feature tracking (CMR-FT).

Methods

Fifty-eight HCM patients, 44 HTN patients, and 25 healthy controls were retrospectively enrolled. LA and RA functions were compared among the three groups. LA-LV correlations were evaluated in the HCM and HTN groups.

Results

LA reservoir (LA total EF, ɛs, and SRs), conduit (LA passive EF, ɛe, SRe), and booster pump (LA booster EF, ɛa, SRa) functions were significantly impaired in HCM and HTN patients compared to healthy controls (HCM vs. HTN vs. healthy controls: ɛs, 24.8 ± 9.8% vs. 31.3 ± 9.3% vs. 25.2 ± 7.2%; ɛe, 11.7 ± 6.7% vs. 16.8 ± 6.9% vs. 25.5 ± 7.5%; ɛa, 13.1 ± 5.8% vs. 14.6 ± 5.5% vs. 16.5 ± 4.5%, p < 0.05). Reservoir and conduit functions were more impaired in HCM patients compared to HTN patients (p < 0.05). LA strains demonstrated significant correlations with LV EF, LV mass index, LV MWT, global longitudinal strain parameters, and native T1 in HCM patients (p < 0.05). The only correlations in HTN were observed between LA reservoir strain (ɛs) and booster pump strain (ɛa) with LV GLS (p < 0.05). RA reservoir function (RA ɛs, SRs) and conduit function (RA ɛe, SRe) were significantly impaired in HCM and HTN patients (p < 0.05), while RA booster pump function (RA ɛa, SRa) was preserved.

Conclusions

LA functions were impaired in HCM and HTN patients with preserved LV EF, with reservoir and conduit functions more affected in HCM patients. Moreover, different LA-LV couplings were apparent in two different diseases, and abnormal LA-LV coupling was emphasized in HTN. Decreased RA reservoir and conduit strains were evident in both HCM and HTN, while booster pump strain was preserved.

Left atrial strain is associated with arrhythmia recurrence after atrial fibrillation ablation: Cardiac magnetic resonance rapid strain vs. feature tracking strain

PURPOSE

The present study assesses different left atrial (LA) strain approaches in relation to atrial fibrillation (AF) recurrence after ablation and compares LA feature tracking (FT) strain to novel rapid LA strain approaches in AF patients.

METHODS

This retrospective single-center study comprised of 110 prospectively recruited AF patients who underwent cardiac magnetic resonance (CMR) imaging in sinus rhythm prior to their first pulmonary vein isolation ablation. LA rapid strain (long axis strain and atrioventricular (AV)-junction strain), LA FT strain, and LA volumes were derived from 2-chamber and 4-chamber cine images. AF recurrence was followed up for 12 months using either 12‑lead ECGs or rhythm Holter monitoring.

RESULTS

Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (122-286) days. LA long axis strain, AV-junction strain, and FT strain were all more impaired in patients with AF recurrence compared to patients without AF recurrence (long axis strain: P < 0.01; AV-junction strain: P < 0.001; FT strain: P < 0.01, respectively). Area under the curve (AUC) values for LA remodeling parameters in association with AF recurrence were 0.68 for long axis strain, 0.68 for AV-junction strain, 0.66 for FT strain, 0.66 for LA volume index. Phasic FT LA strain demonstrated that contractile strain had the highest AUC (0.70).

CONCLUSION

Both LA rapid strain and LA FT strain are associated with arrhythmia recurrence after ablation in AF patients. LA rapid strain can be a convenient and reproducible alternative for LA FT strain to assess LA function in clinical practice.

Diagnostic accuracy of left atrial function and strain for differentiating between acute and chronic myocardial infarction

BACKGROUND

The cardiac magnetic resonance tissue tracking (CMR-TT) technique was used to obtain left atrial strain and strain rate in patients with myocardial infarction (MI) and to evaluate the utility of this technique in the quantitative assessment of myocardial infarction for distinguishing acute from chronic myocardial infarction.

METHODS

We retrospectively analyzed 36 consecutive patients with acute myocardial infarction (AMI) and 29 patients with chronic myocardial infarction (CMI) who underwent CMR and 30 controls. Left atrial (LA) and ventricular functions were quantified by volumetric, and CMR-TT derived strain analysis from long and short left ventricular view cines. Receiver Operating Characteristics (ROC) analysis was used to determine the diagnostic accuracy of CMR-TT strain parameters for discriminating between acute and chronic myocardial infarction.

RESULTS

AMI and CMI participants had impaired LA reservoir function, conduit function and LA booster pump dysfunction compared to the controls. LA strain was more sensitive than LV global strain for the assessment of the MI stage. Peak late-negative SR yielded the best areas under the ROC curve (AUC) of 0.879, showing differentiation between acute and chronic myocardial infarction of all the LA strain parameters obtained. The highest significant differences between chronic myocardial infarction and normal myocardium were also found in the LV strain (p < 0.001) and LA functional parameters (p < 0.001), but there was no difference between AMI and normals.

CONCLUSIONS

CMR-TT-derived LA strain is a potential and robust tool in demonstrating impaired LA mechanics and quantifying LA dynamics, which have high sensitivity and specificity in the differential diagnosis of acute versus chronic myocardial infarction. Their use is thus worth popularizing in clinical application.

Left atrial strain assessment using cardiac computed tomography in patients with hypertrophic cardiomyopathy

PURPOSE

To evaluate left atrial (LA) function in patients with hypertrophic cardiomyopathy (HCM) by LA strain assessment using cardiac computed tomography (CT-derived LA strain).

MATERIALS AND METHODS

This was a retrospective study of 34 patients with HCM and 31 non-HCM patients who underwent cardiac computed tomography (CT) using retrospective electrocardiogram-gated mode. CT images were reconstructed every 5% (0-95%) of the RR intervals. CT-derived LA strain (reservoir [LASr], conduit [LASc], and booster pump strain [LASp]) were semi-automatically analyzed using a dedicated workstation. We also measured the left atrial volume index (LAVI) and left ventricular longitudinal strain (LVLS) for the left atrial and ventricular functional parameters to assess the relationship with CT-derived LA strain.

RESULTS

CT-derived LA strain significantly correlated with LAVI: r = - 0.69, p < 0.001 for LASr; r = - 0.70, p < 0.001 for LASp; and r = - 0.35, p = 0.004 for LASc. CT-derived LA strain also significantly correlated with LVLS: r = - 0.62, p < 0.001 for LASr; r = - 0.67, p < 0.001 for LASc; and r = - 0.42, p = 0.013 for LASp. CT-derived LA strain in patients with HCM was significantly lower than that in non-HCM patients: LASr (20.8 ± 7.6 vs. 31.7 ± 6.1%, p < 0.001); LASc (7.9 ± 3.4 vs. 14.2 ± 5.3%, p < 0.001); and LASp (12.8 ± 5.7 vs. 17.6 ± 4.3%, p < 0.001). Additionally, CT-derived LA strain showed high reproducibility; inter-observer correlation coefficients were 0.94, 0.90, and 0.89 for LASr, LASc, and LASp, respectively.

CONCLUSION

CT-derived LA strain is feasible for quantitative assessment of left atrial function in patients with HCM.

Association of left atrial size and function by cardiac magnetic resonance imaging with long term outcomes in patients with hypertrophic cardiomyopathy

Left atrial (LA) function and strain are being investigated as markers of disease progression in hypertrophic cardiomyopathy (HCM). To assess LA function and strain by cardiac magnetic resonance imaging (MRI) in patients with HCM and evaluate the association of these parameters with long-term clinical outcomes. We retrospectively evaluated 50 HCM patients and 50 patients with no significant cardiovascular disease (control) who underwent clinically indicated cardiac MRI. We calculated LA volumes using the Simpson area-length method to derive LA ejection fraction and expansion index. MRI-derived left atrial reservoir (ƐR), conduit (ƐCD), and contractile strain (ƐCT) were measured using dedicated software. A multivariate regression analysis with endpoints of ventricular tachyarrhythmias (VTA) and heart failure hospitalization (HFH) was performed. HCM patients had significantly higher LV mass, higher LA volumes and lower LA strain compared to controls. During the median follow up of 15.6 months (interquartile range 8.4-35.4 months), 11 patients (22%) experienced a HFH, while 10 patients (20%) had VTA. Multivariate analysis demonstrated that ƐCT (odds ratio (OR) 0.96, confidence interval (CI) 0.83-1.00) and LA ejection fraction (OR 0.89, CI 0.79-1.00) were significantly associated with VTA and HFH respectively.

Reverse remodeling of left atrium assessed by cardiovascular magnetic resonance feature tracking in hypertrophic obstructive cardiomyopathy after septal myectomy

BACKGROUND

Assessing the structure and function of left atrium (LA) is crucial in hypertrophic obstructive cardiomyopathy (HOCM) because LA remodeling correlates with atrial fibrillation. However, few studies have investigated the potential effect of myomectomy on LA phasic remodeling in HOCM after myectomy using cardiovascular magnetic resonance (CMR) feature tracking (FT). This study aims to evaluate the LA structural and functional remodeling with HOCM after myectomy by CMR-FT and to further investigate the determinants of LA reverse remodeling.

METHODS

In this single-center study, we retrospectively studied 88 patients with HOCM who received CMR before and after myectomy between January 2011 and June 2021. Preoperative and postoperative LA parameters derived from CMR-FT were compared, including LA reservoir function (total ejection fraction [EF], total strain [εs], peak positive strain rate [SRs]), conduit function (passive EF, passive strain [εe], peak early negative strain rate [SRe]) and booster function (booster EF, active strain [εa], late peak negative strain rate [SRa]). Eighty-six healthy participants were collected for comparison. Univariate and multivariate linear regression identified variables associated with the rate of change of εa.

RESULTS

Compared with preoperative parameters, LA reservoir function (total EF, εs, SRs), booster function (booster EF, εa, SRa), and SRe were significantly improved after myectomy (all P < 0.05), while no significant differences were observed in passive EF and εe. Postoperative patients with HOCM still had larger LA and worse LA function than healthy controls (all P < 0.05). After analyzing the rates of change in LA parameters, LA boost function, especially εa, showed the most dramatic improvement beyond the improvements in reservoir function, conduit function, and volume. In multivariable regression analysis, minimum LA volume index (adjusted β = - 0.39, P < 0.001) and Δleft ventricular outflow tract (LVOT) pressure gradient (adjusted β = - 0.29, P = 0.003) were significantly related to the rate of change of εa.

CONCLUSIONS

Patients with HOCM after septal myectomy showed LA reverse remodeling with a reduction in LA size and restoration in LA reservoir and booster function but unchanged LA conduit function. Among volumetric and functional changes, booster function had the greatest improvement postoperatively. Besides, preoperative LAVmin index and ΔLVOT might be potential factors associated with the degree of improvement in εa.

Prognostic Value of Left Atrial Reservoir Strain in Left Ventricular Myocardial Noncompaction: A 3.0 T Cardiac Magnetic Resonance Feature Tracking Study

BACKGROUND

The relationship of left atrial (LA) strain to high-risk heart failure (HF) events in patients with left ventricular myocardial noncompaction (LVNC) remains to be thoroughly investigated.

PURPOSE

To evaluate the LA performance in patients with LVNC, and to investigate the prognostic value of LA phasic strain on high-risk HF events, and its influencing factors.

STUDY TYPE

Retrospective.

POPULATION

A total of 95 LVNC patients (74 with LA enlargement [LAE] and 21 without LAE) and 50 healthy controls.

FIELD STRENGTH/SEQUENCE

A 3.0 T, balanced steady-state free-precession cine imaging.

ASSESSMENT

LA longitudinal strains were measured by cardiac MRI feature tracking technique. LA volume index (LAVI) and LA ejection fraction (LAEF) were calculated. Their intraobserver and interobserver reproducibility were evaluated. The primary outcome was high-risk HF events, a composite of first HF hospitalization, hospitalization for worsening HF and death from HF.

STATISTICAL TESTS

Student's t/Mann-Whitney U, one-way analysis of variance/Kruskal-Wallis, Chi-squared, receiver operating characteristic, Kaplan-Meier, log-rank, Cox regression, Pearson and Spearman correlation and linear regression analyses were performed. The significance threshold was set at P < 0 .05.

RESULTS

LAEF and LA longitudinal strains decreased in LVNC patients irrespective of the presence of LAE. During a median follow-up of 32.17 months, high-risk HF occurred in 13 (13.68%) patients. Patients with increased LAVI, decreased LAEF and decreased LA longitudinal strain had significantly higher risks of high-risk HF events. In patients with LVNC, LA reservoir strain (εs) was independently associated with high-risk HF (hazard ratio = 23.208 [95% CI: 2.993-179.967]). LV global longitudinal strain (LV GLS) (β = -1.783 [95% CI: -2.493 to -1.073]) was significantly and independently associated with εs. Intraobserver and interobserver reproducibility was excellent for LAVI, LAEF, and LA strain.

CONCLUSION

In patients with LVNC, εs was an independent predictor for high-risk HF events. LV GLS was an independent determinant of εs in LVNC.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 4.

Predictive value of left atrial strain analysis in adverse clinical events in patients with hypertrophic cardiomyopathy: a CMR study

BACKGROUND

A subset of patients with hypertrophic cardiomyopathy (HCM) will experience adverse clinical events such as heart failure (HF), cardiovascular death, and new-onset atrial fibrillation (AF). Current risk stratification methods are imperfect and limit the identification of patients at high risk for HCM. This study aimed to evaluate the role of cardiac magnetic resonance (CMR)-derived left atrial strain parameters in the occurrence of adverse clinical events in patients with HCM.

METHODS

Left atrial (LA) structural, functional, and strain parameters were evaluated in 99 patients with HCM and compared with 89 age-, sex-, and BMI-matched control subjects. LA strain parameters were derived from CMR two- and four-chamber cine images by a semiautomatic method. LA strain parameters include global longitudinal strain (GLS) and global circumferential strain (GCS). The LA GLS includes reservoir strain (GLS reservoir), conduit strain (GLS conduit), and booster strain (GLS booster). Three LA GLS strain rate (SR) parameters were derived: SR reservoir, SR conduit, and SR booster. The primary endpoint was set as a composite of adverse clinical events, including SCD, new-onset or worsening to hospitalized HF, new-onset AF, thromboembolic events, and fatal ventricular arrhythmias.

RESULTS

LA GLS, GLS SR and GCS were impaired in HCM patients compared to control subjects (all p < 0.001). After a mean follow-up of 37.94 ± 23.69 months, 18 HCM patients reached the primary endpoint. LA GLS, GLS SR, and GCS were significantly lower in HCM patients with adverse clinical events than in those without adverse clinical events (all p < 0.05). In stepwise multiple Cox regression analysis, LV SV, LA diameter, pre-contraction LAV (LAV pre-ac), passive LA ejection fraction (EF), and LA GLS booster were all independent determinants of adverse clinical events. LA GLS booster ≤ 8.9% was the strongest determinant (HR = 8.9 [95%CI (1.951, 40.933)], p = 0.005). Finally, LA GLS booster provided predictive adverse clinical events value (AUC = 0.86 [95%CI 0.77-0.98]) that exceeded traditional outcome predictors.

CONCLUSION

LA strain assessment, a measure of LA function, provides additional predictive information for established predictors of HCM patients. LA GLS booster was independently associated with adverse clinical events in patients with HCM.

Cardiovascular magnetic resonance myocardial feature tracking for the determination of left atrial strain in hypertensive left ventricular hypertrophy and hypertrophic cardiomyopathy

AIM

To measure the left atrial (LA) function in patients with hypertrophic cardiomyopathy (HCM; with [OHCM] and without obstruction [NOHCM]) and hypertension-related left ventricular hypertrophy (H-LVH) using cardiovascular magnetic resonance imaging feature tracking (CMR-FT).

MATERIALS AND METHODS

Patients who met the criteria for HCM (n=68), H-LVH (n=46), and 30 healthy controls participated. Left atrial strain was analysed using CMR-FT in cine images with two and four chambers.

RESULTS

The strain rate and LA strain measurements showed that patients with HCM, and H-LVH had impaired conduit and reservoir functions (versus controls). These capacities were more severely impaired in OHCM than those seen in NOHCM and H-LVH. The LA volume parameters (LAVIpac, LAVImin and LAVImax) from the OHCM group were higher than both the NOHCM and H-LVH groups (all p<0.05). There were differences between the OHCM and H-LVH groups in terms of the parameters for LA reservoir function (εs), booster pump function (SRa), and conduit function (SRe, LA passive EF, εe; p<0.05). The strongest correlations included the associations between LA total EF and εs, εe and LA passive EF, and SRe and LA passive EF.

CONCLUSION

CMR-FT can reliably identify LA dysfunction and deformation in the early stages of HCM and H-LVH.

Left atrial strain correlates with severity of cardiac involvement in Anderson-Fabry disease

OBJECTIVES

Cardiac involvement in Anderson-Fabry disease (AFD) results in myocardial lipid depositions. An early diagnosis can maximize therapeutic benefit. Thus, this study aims to investigate the potential of cardiac MRI (CMR) based parameters of left atrial (LA) function and strain to detect early stages of AFD.

METHODS

Patients (n = 58, age 40 (29-51) years, 31 female) with genetically proven AFD had undergone CMR including left ventricular (LV) volumetry, mass index (LVMi), T1, and late gadolinium enhancement, complemented by LA and LV strain measurements and atrial emptying fractions. Patients were stratified into three disease phases and compared to age and sex-matched healthy controls (HC, n = 58, age 41 [26-56] years, 31 female).

RESULTS

A total of 19 early-, 20 intermediate-, and 19 advanced-phase patients were included. LV and LA reservoir strain was significantly impaired in all AFD phases, including early disease (both p < 0.001). In contrast, LA volumetry, T1, and LVMi showed no significant differences between the early phase and HC (p > 0.05). In the intermediate phase, LVMi and T1 demonstrated significant differences. In advanced phase, all parameters except active emptying fractions differed significantly from HC. ROC curve analyses of early disease phases revealed superior diagnostic confidence for the LA reservoir strain (AUC 0.88, sensitivity 89%, specificity 75%) over the LV strain (AUC 0.82).

CONCLUSIONS

LA reservoir strain showed impairment in early AFD and significantly correlated with disease severity. The novel approach performed better in identifying early disease than the established approach using LVMi and T1. Further studies are needed to evaluate whether these results justify earlier initiation of therapy and help minimize cardiac complications.

KEY POINTS

• Parameters of left atrial function and deformation showed impairments in the early stages of Anderson-Fabry disease and correlated significantly with the severity of Anderson-Fabry disease. • Left atrial reservoir strain performed superior to ventricular strain in detecting early myocardial involvement in Anderson-Fabry disease and improved diagnostic accuracies of approaches already using ventricular strain. • Further studies are needed to evaluate whether earlier initiation of enzyme replacement therapy based on these results can help minimize cardiac complications from Anderson-Fabry disease.

COVID-19 and elite sport: Cardiovascular implications and return-to-play

Curtailing elite sports during the coronavirus disease 2019 (COVID-19) pandemic was necessary to prevent widespread viral transmission. Now that elite sport and international competitions have been largely restored, there is still a need to devise appropriate screening and management pathways for athletes with a history of, or current, COVID-19 infection. These approaches should support the decision-making process of coaches, sports medicine practitioners and the athlete about the suitability to return to training and competition activities. In the absence of longitudinal data sets from athlete populations, the incidence of developing prolonged and debilitating symptoms (i.e., Long COVID) that affects a return to training and competition remains a challenge to sports and exercise scientists, sports medicine practitioners and clinical groups. As the world attempts to adjust toward 'living with COVID-19' the very nature of elite and international sporting competition poses a risk to athlete welfare that must be screened for and managed with bespoke protocols that consider the cardiovascular implications for performance.

Sex differences in atrial remodeling and its relationship with myocardial fibrosis in hypertrophic obstructive cardiomyopathy

BACKGROUND

This study aimed to explore the effect of sex on left atrial (LA) remodeling and its relationship with myocardial fibrosis in patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODS AND RESULTS

A total of 85 patients with HOCM were enrolled. Myocardial fibrosis was quantified by the collagen volume fraction (CVF) in myocardial samples. The early atrial peak of emptying rate (PER-E) was assessed by LA volume/time (V/t) curves derived from cardiac magnetic resonance (CMR) imaging analysis. The PER-E index was PER-E normalized by left ventricular (LV) filling volume. Patients with HOCM showed a lower PER-E index than healthy controls (P = 0.027). Compared with men, the PER-E (P < 0.001) and the PER-E indexes (P = 0.012) in women were lower. In CVF-stratified subgroups, a sex difference in the PER-E index was eliminated (P > 0.05). The CVF was correlated with the PER-E and PER-E indexes in both sexes (all P-values were <0.05). In multivariate regression analysis, sex (P = 0.007) and CVF (P < 0.001) were independently correlated with PER-E (all P-values were <0.05).

CONCLUSION

Patients with HOCM presented LA reverse remodeling. Impaired LA function was more common in female patients with HOCM due to their susceptibility to myocardial fibrosis.

Associations between fully-automated, 3D-based functional analysis of the left atrium and classification schemes in atrial fibrillation

Background

Atrial fibrillation (AF) has been linked to left atrial (LA) enlargement. Whereas most studies focused on 2D-based estimation of static LA volume (LAV), we used a fully-automatic convolutional neural network (CNN) for time-resolved (CINE) volumetry of the whole LA on cardiac MRI (cMRI). Aim was to investigate associations between functional parameters from fully-automated, 3D-based analysis of the LA and current classification schemes in AF.

Methods

We retrospectively analyzed consecutive AF patients who underwent cMRI on 1.5T systems including a stack of oblique-axial CINE series covering the whole LA. The LA was automatically segmented by a validated CNN. In the resulting volume-time curves, maximum, minimum and LAV before atrial contraction were automatically identified. Active, passive and total LA emptying fractions (LAEF) were calculated and compared to clinical classifications (AF Burden score (AFBS), increased stroke risk (CHA₂DS₂VASc≥2), AF type (paroxysmal/persistent), EHRA score, and AF risk factors). Moreover, multivariable linear regression models (mLRM) were used to identify associations with AF risk factors.

Results

Overall, 102 patients (age 61±9 years, 17% female) were analyzed. Active LAEF (LAEF_active) decreased significantly with an increase of AFBS (minimal: 44.0%, mild: 36.2%, moderate: 31.7%, severe: 20.8%, p<0.003) which was primarily caused by an increase of minimum LAV. Likewise, LAEF_active was lower in patients with increased stroke risk (30.7% vs. 38.9%, p = 0.002). AF type and EHRA score did not show significant differences between groups. In mLRM, a decrease of LAEF_active was associated with higher age (per year: -0.3%, p = 0.02), higher AFBS (per category: -4.2%, p<0.03) and heart failure (-12.1%, p<0.04).

Conclusions

Fully-automatic morphometry of the whole LA derived from cMRI showed significant relationships between LAEF_active with increased stroke risk and severity of AFBS. Furthermore, higher age, higher AFBS and presence of heart failure were independent predictors of reduced LAEF_active, indicating its potential usefulness as an imaging biomarker.

Isotropic 3D compressed sensing (CS) based sequence is comparable to 2D-LGE in left ventricular scar quantification in different disease entities

The goal of this study was to evaluate a three-dimensional compressed sensing (3D-CS) LGE prototype sequence for the detection and quantification of myocardial fibrosis in patients with chronic myocardial infarction (CMI) and myocarditis (MYC) compared with a 2D-LGE standard. Patients with left-ventricular LGE due to CMI (n = 33) or MYC (n = 20) were prospectively recruited. 2D-LGE and 3D-CS images were acquired in random order at 1.5 Tesla. 3D-CS short axis (SAX) images were reconstructed corresponding to 2D SAX images. LGE was quantitatively assessed on patient and segment level using semi-automated threshold methods. Image quality (4-point scoring system), Contrast-ratio (CR) and acquisition times were compared. There was no significant difference between 2D and 3D sequences regarding global LGE (%) (CMI [2D-LGE: 11.4 ± 7.5; 3D-LGE: 11.5 ± 8.5; p = 0.99]; MYC [2D-LGE: 27.0 ± 15.7; 3D-LGE: 26.2 ± 13.1; p = 0.70]) and segmental LGE-extent (p = 0.63). 3D-CS identified papillary infarction in 5 cases which was not present in 2D images. 2D-LGE acquisition time was shorter (2D: median: 06:59 min [IQR: 05:51-08:18]; 3D: 14:48 min [12:45-16:57]). 3D-CS obtained better quality scores (2D: 2.06 ± 0.56 vs. 3D: 2.29 ± 0.61). CR did not differ (p = 0.63) between basal and apical regions in 3D-CS images but decreased significantly in 2D apical images (CR basal: 2D: 0.77 ± 0.11, 3D: 0.59 ± 0.10; CR apical: 2D: 0.64 ± 0.17, 3D: 0.53 ± 0.11). 3D-LGE shows high congruency with standard LGE and allows better identification of small lesions. However, the current 3D-CS LGE sequence did not provide PSIR reconstruction and acquisition time was longer.

Enhanced 4D Flow MRI-Based CFD with Adaptive Mesh Refinement for Flow Dynamics Assessment in Coarctation of the Aorta

4D Flow MRI is a diagnostic tool that can visualize and quantify patient-specific hemodynamics and help interventionalists optimize treatment strategies for repairing coarctation of the aorta (COA). Despite recent developments in 4D Flow MRI, shortcomings include phase-offset errors, limited spatiotemporal resolution, aliasing, inaccuracies due to slow aneurysmal flows, and distortion of images due to metallic artifact from vascular stents. To address these limitations, we developed a framework utilizing Computational Fluid Dynamics (CFD) with Adaptive Mesh Refinement (AMR) that enhances 4D Flow MRI visualization/quantification. We applied this framework to five pediatric patients with COA, providing in-vivo and in-silico datasets, pre- and post-intervention. These two data sets were compared and showed that CFD flow rates were within 9.6% of 4D Flow MRI, which is within a clinically acceptable range. CFD simulated slow aneurysmal flow, which MRI failed to capture due to high relative velocity encoding (Venc). CFD successfully predicted in-stent blood flow, which was not visible in the in-vivo data due to susceptibility artifact. AMR improved spatial resolution by factors of 101 to 103 and temporal resolution four-fold. This computational framework has strong potential to optimize visualization/quantification of aneurysmal and in-stent flows, improve spatiotemporal resolution, and assess hemodynamic efficiency post-COA treatment.

The predictive value of fast semi-automated left atrial long-axis strain analysis for atrial fibrillation in hypertrophic cardiomyopathy

OBJECTIVES

Hypertrophic cardiomyopathy (HCM) patients are closely related to LA functional impairment. Left atrial (LA) strain provides more insight into LA function. The study aimed to investigate the left atrial dysfunction of HCM patients by rapid semi-automatic method and determine the predictive value of left atrial long-axis strain (LAS) for atrial fibrillation (AF).

METHODS

We enrolled 372 HCM patients and 100 healthy participants to assess the LA functional parameters. LAS was obtained by semi-automated tracking of the distance between the mid-posterior point of LA wall which is defined as the intersection of the LA long axis and the posterior wall, and the origins of the mitral valve. The inferior and anterior mitral valve annular insertion points on the 2-chamber view and the lateral and septal insertion points on the 4-chamber view were chosen as the origins of the mitral valve. The clinical outcome was defined as detecting the onset of AF.

RESULTS

The LA strain values were analyzed as 20.8 ± 7.48% for ε_s, 9.81 ± 5.09% for ε_e, and 10.91 ± 4.24% for ε_a in HCM patients, which decreased significantly compared with normal controls. Significant correlations were detected between LV functional parameters and LA strain. During a median follow-up of 61 months, 44 (11.8%) patients developed AF. In the Cox regression analysis, LA strain was identified as a significant predictor of the onset of AF.

CONCLUSIONS

HCM patients had impairment of LA strain before LA enlargement and reduced EF. LA-LAS can be used as a predictive value for predicting the occurrence of AF in HCM patients.

KEY POINTS

• Fast semi-automated long-axis strain analysis by CMR is feasible and effective for evaluating the LA longitudinal function. • Hypertrophic cardiomyopathy patients show significant impairment of left atrial strain before LA enlargement. • The left atrial long-axis strain was an independent predictor of atrial fibrillation in hypertrophic cardiomyopathy.

A 3D Convolutional Neural Network with Gradient Guidance for Image Super-Resolution of Late Gadolinium Enhanced Cardiac MRI

In this paper, we describe a 3D convolutional neural network (CNN) framework to compute and generate super-resolution late gadolinium enhanced (LGE) cardiac magnetic resonance imaging (MRI) images. The proposed CNN framework consists of two branches: a super-resolution branch with a 3D dense deep back-projection network (DBPN) as the backbone to learn the mapping of low-resolution LGE cardiac volumes to high-resolution LGE cardiac volumes, and a gradient branch that learns the mapping of the gradient map of low resolution LGE cardiac volumes to the gradient map of their high-resolution counterparts. The gradient branch of the CNN provides additional cardiac structure information to the super-resolution branch to generate structurally more accurate super-resolution LGE MRI images. We conducted our experiments on the 2018 atrial segmentation challenge dataset. The proposed CNN framework achieved a mean peak signal-to-noise ratio (PSNR) of 30.91 and 25.66 and a mean structural similarity index measure (SSIM) of 0.91 and 0.75 on training the model on low-resolution images downsamp led by a scale factor of 2 and 4, respectively.

Cardiac Computed Tomography-Derived Left Atrial Strain and Volume in Pediatric Patients With Congenital Heart Disease: A Comparative Analysis With Transthoracic Echocardiography

Purpose

This study aimed at exploring the feasibility and reproducibility of CCT for the measurement of Left Atrial (LA) strain and volume compared with transthoracic echocardiography (TTE) in pediatric patients with congenital heart disease (CHD).

Materials and Methods

The present study included 43 postoperative patients with CHD (7.39 ± 3.64 years, 56% male) who underwent clinically indicated CCT, and all patients underwent additional TTE on the same day. LA strain and volume parameters were measured by dedicated software. The correlation and agreement of LA strain and volume parameters were assessed using Pearson’s correlation coefficient and Bland-Altman analysis. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

Results

All strain parameters of CCT were lower compared to TTE (reservoir strain: 28.37 ± 6.92 vs. 32.15 ± 8.15, respectively; conduit strain: 21.33 ± 6.46 vs. 24.23 ± 7.75, respectively; booster strain: 7.04 ± 2.74 vs. 7.92 ± 3.56). While the volume parameters of CCT were higher compared to TTE (LAV: 29.60 ± 19.01 vs. 25.66 ± 17.60, respectively; LAVi: 30.36 ± 22.31 vs. 28.63 ± 19.25, respectively). Both LA strain and volume measurements showed good correlation and agreement between the two modalities (r = 0.63–0.87, p < 0.001). CT-derived LA strain and volume measurements showed good intra- and inter-observer reproducibility using prototype software (ICC = 0.78–0.96).

Conclusions

CCT was feasible for measuring LA strain and volume with good correlation and high reproducibility as compared with TTE. As a complementary modality, CCT can regard as an accepted method in the evaluation of LA function in pediatric patients with CHD

Prognostic value of left atrial longitudinal strain by cardiac MRI feature tracking in atrial fibrillation patients with mitral valve disease

AIM

To evaluate the prognostic value of left atrial global longitudinal strain (LAGLS) in atrial fibrillation (AF) patients with mitral valve disease (MVD).

MATERIALS AND METHODS

In this single-centre retrospective study, 48 consecutive AF patients with MVD who underwent cardiac magnetic resonance imaging (CMRI) before surgery were enrolled. The LAGLS was assessed by cine-CMRI images and feature tracking (CMRI-FT) technique. Logistic regression and receiver operating characteristic (ROC) analysis were performed to identify the value of LAGLS in predicting atrial tachyarrhythmia recurrence after surgery.

RESULTS

The LAGLS level of the total patients was 4.4% (interquartile range: 2.7-9.2%). LAGLS was significantly associated with many evaluated parameters of severity of disease including biventricular volumetric function, left atrial (LA) ejection fraction, and the European System for Cardiac Operative Risk Evaluation II score (all p<0.05). Multivariate Cox analysis showed that LAGLS (hazard ratio = 0.52, 95% confidence interval [CI]: 0.31, 0.87; p=0.013) was an independent predictor of atrial tachyarrhythmia recurrence after adjustment for LA diameter, LA and biventricular ejection fraction, aetiology of MVD (rheumatic or degenerative), and surgical procedure (valve surgery alone or valve surgery combined with Maze IV). The optimal cut-off value of LAGLS was 4.1% for predicting recurrent atrial tachyarrhythmia (sensitivity 81.8%, specificity 78.4%) and the area under the ROC curve was 0.854 (95% CI: 0.711, 0.996, p<0.001).

CONCLUSION

CMRI-FT-derived LAGLS may act as a novel non-invasive imaging biomarker with which to evaluate the severity of disease and offer independent prognostic information for atrial tachyarrhythmia recurrence after surgery in AF patients with MVD.

Improved catheter tracking during cardiovascular magnetic resonance-guided cardiac catheterization using overlay visualization

INTRODUCTION

Cardiovascular magnetic resonance (CMR)-guided cardiac catheterization is becoming more widespread due to the ability to acquire both functional CMR measurements and diagnostic catheterization data without exposing patients to ionizing radiation. However, the real-time imaging sequences used for catheter guidance during these procedures are limited in resolution and the anatomical detail they can provide. In this study, we propose a passive catheter tracking approach which simultaneously improves catheter tracking and visualization of the anatomy.

METHODS

60 patients with congenital heart disease underwent CMR-guided cardiac catheterization on a 1.5T CMR scanner (Ingenia, Philips Healthcare, Best the Netherlands) using the Philips iSuite system. The proposed T1-overlay technique uses a commercially available heavily T1-weighted sequence to image the catheter, and overlays it on a high-resolution 3D dataset within iSuite in real-time. Suppressed tissue in the real-time images enables the use of a thick imaging slab to assist in tracking of the catheter. Improvement in catheter visualization time was compared between T1-overlay and the conventional invasive CMR (iCMR) balanced steady state free precession (bSSFP) sequence. This technique also enabled selective angiography visualization for real-time evaluation of blood flow dynamics (such as pulmonary transit time), similar to direct contrast injection under standard fluoroscopy. Estimates of pulmonary transit time using iCMR were validated using x-ray fluoroscopy in 16 patients.

RESULTS

The T1-overlay approach significantly increased the time that the catheter tip was kept in view by the technologist compared to the bSSFP sequence conventionally used for iCMR. The resulting images received higher ratings for blood/balloon contrast, anatomy visualization, and overall suitability for iCMR guidance by three cardiologists. iCMR selective angiography using T1-overlay also provided accurate estimates of pulmonary transit time that agreed well with x-ray fluoroscopy.

CONCLUSION

We demonstrate a new passive catheter tracking technique using the iSuite platform that improves visualization of the catheter and cardiac anatomy. These improvements significantly increase the time that the catheter tip is seen throughout the procedure. We also demonstrate the feasibility of iCMR selective angiography for the measurement of pulmonary transit time.

Left atrium phasic impairments in paroxysmal atrial fibrillation patients assessed by cardiovascular magnetic resonance feature tracking

Atrial fibrillation (AF) is an abnormal and irregular heartbeat caused by uncoordinated electrical impulses in the left atrium (LA), which could induce lasting changes in the heart tissue or could be a consequence of underlying cardiac disease. This study aimed to assess the left atrial phasic function and deformation in paroxysmal AF (PAF) patients—who had not received radiofrequency ablation and had no signs of permanent AF—using the cardiovascular magnetic resonance (CMR) feature-tracking (FT) technique. Fifty subjects (27 PAF patients and 23 controls) were included and examined with CMR. Their LA volume, LA function, LA longitudinal strain (LS) and LA strain rate were assessed in the LA reservoir, conduit, and contractile phases. PAF patients exhibited higher LA volumes than controls, while their LA emptying fraction and LA LS was significantly lower in all three phases. In contrast, the corresponding emptying volumes (total, passive and active) were similar in both groups. The LA volumetric rates from CMR-derived volume curves differed significantly in PAF patients vs controls in the reservoir and contractile phases. In contrast, the equivalent LV volumetric rates were similar. This study suggests that assessing the LA phasic function could offer insight into early LA impairments for PAF patients.

Synthetic MRI for Radiotherapy Planning for Brain and Prostate Cancers: Phantom Validation and Patient Evaluation

Purpose

We aimed to evaluate the accuracy of T₁ and T₂ mappings derived from a multispectral pulse sequence (magnetic resonance image compilation, MAGiC^®) on 1.5-T MRI and with conventional sequences [gradient echo with variable flip angle (GRE-VFA) and multi-echo spin echo (ME-SE)] compared to the reference values for the purpose of radiotherapy treatment planning.

Methods

The accuracy of T₁ and T₂ measurements was evaluated with 2 coils [head and neck unit (HNU) and BODY coils] on phantoms using descriptive statistics and Bland–Altman analysis. The reproducibility and repeatability of T₁ and T₂ measurements were performed on 15 sessions with the HNU coil. The T₁ and T₂ synthetic sequences obtained by both methods were evaluated according to quality assurance (QA) requirements for radiotherapy. T₁ and T₂in vivo measurements of the brain or prostate tissues of two groups of five subjects were also compared.

Results

The phantom results showed good agreement (mean bias, 8.4%) between the two measurement methods for T₁ values between 490 and 2,385 ms and T₂ values between 25 and 400 ms. MAGiC^® gave discordant results for T₁ values below 220 ms (bias with the reference values, from 38% to 1,620%). T₂ measurements were accurately estimated below 400 ms (mean bias, 8.5%) by both methods. The QA assessments are in agreement with the recommendations of imaging for contouring purposes for radiotherapy planning. On patient data of the brain and prostate, the measurements of T₁ and T₂ by the two quantitative MRI (qMRI) methods were comparable (max difference, <7%).

Conclusion

This study shows that the accuracy, reproducibility, and repeatability of the multispectral pulse sequence (MAGiC^®) were compatible with its use for radiotherapy treatment planning in a range of values corresponding to soft tissues. Even validated for brain imaging, MAGiC^® could potentially be used for prostate qMRI.

Comparison of Nonclassic and Classic Phenotype of Hypertrophic Cardiomyopathy Focused on Prognostic Cardiac Magnetic Resonance Parameters: A Single-Center Observational Study

Patients with nonclassic phenotypes (NCP)—more advanced stages of hypertrophic cardiomyopathy (HCM)—constitute an intriguing and heterogeneous group that is difficult to diagnose, risk-stratify, and treat, and often neglected in research projects. We aimed to compare cardiac magnetic resonance (CMR) parameters in NCP versus classic phenotypes (CP) of HCM with special emphasis given to the parameters of established and potential prognostic importance, including numerous variables not used in everyday clinical practice. The CMR studies of 88 patients performed from 2011 to 2019 were postprocessed according to the study protocol to obtain standard and non-standard parameters. In NCP, the late gadolinium enhancement extent expressed as percent of left ventricular mass (%LGE) and left ventricular mass index (LVMI) were higher, left atrium emptying fraction (LAEF) was lower, minimal left atrial volume (LAV min) was greater, and myocardial contraction fraction (MCF) and left ventricular global function index (LVGFI) were lower than in CP (p < 0.001 for all). In contrast, HCM risk score and left ventricular maximal thickness (LVMT) were similar in NCP and CP patients. No left ventricular outflow tract obstruction (LVOTO) was observed in the NCP group. Left ventricular outflow tract diameter (LVOT), aortic valve diameter (Ao), and LVOT/Ao ratio were significantly higher and anterior mitral leaflet (AML)/LVOT ratio was lower in the NCP compared to the CP group. In conclusion, significant differences in nonstandard CMR parameters were noted between the nonclassic and classic HCM phenotypes that may contribute to future studies on disease stages and risk stratification in HCM.

The emerging role of atrial strain assessed by cardiac MRI in different cardiovascular settings: an up-to-date review

The left atrium (LA) has a crucial function in maintaining left ventricular filling, which is responsible for about one-third of all cardiac filling. A growing body of evidence shows that LA is involved in several cardiovascular diseases from a clinical and prognostic standpoint. LA enlargement has been recognized as a predictor of the outcomes of many diseases. However, LA enlargement itself does not explain the whole LA's function during the cardiac cycle. For this reason, the recently proposed assessment of atrial strain at advanced cardiac magnetic resonance (CMR) enables the usual limitations of the sole LA volumetric measurement to be overcome. Moreover, the left atrial strain impairment might allow several cardiovascular diseases to be detected at an earlier stage. While traditional CMR has a central role in assessing LA volume and, through cine sequences, a marginal role in evaluating LA function, feature tracking at advanced CMR (CMR-FT) has been increasingly confirmed as a feasible and reproducible technique for assessing LA function through strain. In comparison to atrial function evaluations via speckle tracking echocardiography, CMR-FT has a higher spatial resolution, larger field of view, and better reproducibility. In this literature review on atrial strain analysis, we describe the strengths, limitations, recent applications, and promising developments of studying atrial function using CMR-FT in clinical practice. KEY POINTS: • The left atrium has a crucial function in maintaining left ventricular filling; left atrial size has been recognized as a predictor of the outcomes of many diseases. • Left atrial strain has been confirmed as a marker of atrial functional status and demonstrated to be a sensitive tool in the subclinical phase of a disease. • A comprehensive evaluation of the three phases of atrial function by CMR-FT demonstrates an impairment before the onset of atrial enlargement, thus helping clinicians in their decision-making and improving patient outcomes.

Impact of different degrees of left ventricular strain on left atrial mechanics in heart failure with preserved ejection fraction

Background

Impairment of left atrial (LA) function is linked to left ventricle (LV) mechanics in patients with heart failure with preserved ejection fraction (HFpEF). In this study, we set forth to determine the difference in LA mechanics compared between HFpEF patients with different degrees of LV strains using the cardiac magnetic resonance feature tracking technique.

Methods

This retrospective study enrolled 79 patients with prior heart failure event and LV ejection fraction (LVEF) ≥ 50% (HFpEF group) together with 2:1 matched controls. LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS); LA emptying fraction (LAEF); and, LA strains consisting of reservoir phase strain (LAS_r), conduit phase strain (LAS_cd), and contraction phase strain (LAS_ct) were derived from cine images. All LA parameters were compared between HFpEF subgroups (lower and higher LV strain stratified by the median of each LV strain value) and controls.

Results

A total of 237 subjects were included. HFpEF had a lower LAEF and LA strain values compared with controls. The mean GLS value was significantly different between HFpEF and controls (− 13.3 ± 3.4% vs. − 15.4 ± 2.2%, p < 0.001). HFpEF with lower GLS (value ≥  − 13.1%) had significantly impaired LA mechanical parameters compared with both HFpEF with higher GLS and controls independent of potential confounders, as follows: LAEF (38.8 ± 16.6% vs. 48.6 ± 15.7% and 54.2 ± 12.2%), LAS_r (14.6 ± 7.1% vs. 24.3 ± 9.6% and 26.7 ± 8.8%), and LAS_cd (− 6.6 ± 3.9% vs. − 12.9 ± 6.0% and − 14.7 ± 7.4%) (post hoc analysis of variance p < 0.05 for all comparisons). Similarly, HFpEF with lower GCS (value ≥  − 16.6%) or lower GRS (value < 27.9%) also had significant impairment of LAS_r and LAS_cd compared with the higher strain group and controls. Abnormal LAEF (< 50%) and abnormal LAS_r (< 23%) are independently associated with NYHA class ≥ II (Odds ratio [OR] 3.894 [95% CI 2.202–6.885] p < 0.001, adjusted OR 3.382 [1.791–6.389] p < 0.001 for abnormal LAEF; and OR 2.613 [1.497–4.562] p = 0.001, adjusted OR 2.064 [1.118–2.110] p = 0.021 for abnormal LAS_r).

Conclusions

Patients with HFpEF were found to have impaired LV and LA mechanics. Abnormal LA mechanics was highly prevalent in HFpEF patients with lower LV strain and significantly associated with the symptomatic status of the patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02608-7.

A systematic review and meta-analysis of the impact of the left atrial appendage closure on left atrial function

Background

Left atrial (LA) appendage closure (LAAC) is effective in patients with atrial fibrillation who are not candidates for long‐term anticoagulation. However, the impact of LAAC on LA function is unknown. The aim of this study is to evaluate the impact of LAAC on atrial function.

Methods

This meta‐analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. A search strategy was designed to utilize PubMed/Medline, EMBASE, and Google scholar for studies showing the effect of LAAC on the LA function from inception to November 20, 2021. The standardized mean difference (SMD) was calculated from the means and standard deviations.

Results

Of 247 studies initially identified, 8 studies comprising 260 patients were included in the final analysis. There was a significant increase in LA emptying fraction following LAAC compared with preoperative function (SMD: 0.53; 95% confidence interval [CI]: 0.04–1.01; p = .03; I² = 75%). In contrast, there were no significant differences in LA volume (SMD: −0.07; 95% CI: −0.82–0.69; p = .86; I² = 92%) peak atrial longitudinal strain (SMD: 0.50; 95% CI: −0.08–1.08; p = .09; I² = 89%), peak atrial contraction strain (SMD: 0.38; 95% CI: −0.22–0.99; p = .21; I² = 81%), strain during atrial contraction (SMD: −0.24; 95% CI: −0.61–0.13; p = .20; I² = 0%), strain during ventricular systole (SMD: 0.47; 95% CI: −0.32–1.27; p = .24; I² = 89%), strain during ventricular diastole (SMD: 0.09; 95% CI: −0.32–0.51; p = .66; I² = 65%).

Conclusion

LAAC is associated with improvement in the left atrial emptying fraction, but did not significantly influence other parameters.

Assessing left atrial function in patients with atrial fibrillation and valvular heart disease using cardiovascular magnetic resonance imaging

Background

Atrial fibrillation (AF) is common arrhythmia in valvular heart disease (VHD) and is associated with adverse outcomes.

Hypothesis

To evaluate the left atrial (LA) function in patients with AF‐VHD by cardiovascular magnetic resonance imaging feature tracking (CMR‐FT) using LA strain (ε_s/ε_e/ε_a) and their corresponding strain rate (SRs/SRe/SRa).

Methods

This was a retrospective cross‐sectional inter‐reader and intra‐reader reproducibility conducted from July 1, 2020, to January 31, 2021. A total of 39 patients with AF‐VHD (rheumatic heart valvular disease [RHVD] [n = 22], degenerative heart valvular disease [DHVD] [n = 17]) underwent MRI scans performed with drug‐controlled heart rate before correcting the rhythm and valves through maze procedure. Fifteen participants with normal cardiac MRI were included as healthy control. ε_s/SRs, ε_e/SRe, and ε_a/SRa, corresponding to LA reservoir, conduit, and booster‐pump function, were assessed using Feature Tracking software (CVI42 v5.12.1).

Results

Compared with healthy controls, LA global strain parameters (ε_s/ε_e/ε_a/SRs/SRe/SRa) were significantly decreased (all p < 0.001), while LA size and volume were increased in AF‐VHD group (all p < 0.001). In the subgroup, RHVD group showed lower LA total ejection fraction (LATEF) and strain data than DHVD group (12.6% ± 3.3% vs. 19.4 ± 8.6, p = 0.001). Decreased LATEF was significantly related to altered LA strain and strain rate, especially in ε_s, ε_e, and SRs (Pearson/Spearman r/ρ = 0.856/0.837/0.562, respectively; all p < 0.001). Interstudy and intrastudy reproducibility were consistent for LA volumetry and strain parameters (intraclass correlation coefficient: 0.88–0.99).

Conclusions

CMR‐FT can be used to assess the LA strain parameters, and identify LA dysfunction and deformation noninvasively, which could be a helpful functional imaging biomarker in the clinical treatment of AF‐VHD.

Left atrial dysfunction may precede left atrial enlargement and abnormal left ventricular longitudinal function: a cardiac MR feature tracking study

Background

The role of the dysfunction of left atrium in the occurrence and development of cardiovascular disease has been gradually recognized. We aim to compare the impact on left atrial (LA) function between patients with hypertrophic cardiomyopathy (HCM) and hypertension (HTN) without LA enlargement using cardiovascular magnetic resonance feature tracking (CMR-FT), and if possible, explore the capability of LA function for providing clinical implication and predicting clinical adverse events in the early stage of cardiovascular disease.

Methods

Consecutive 60 HCM patients and 60 HTN patients with normal LA size among 1413 patients who underwent CMR were retrospectively analyzed as well as 60 controls. Left atrial and ventricular functions were quantified by volumetric and CMR-FT derived strain analysis from long and short left ventricular view cines. The primary endpoint was a composite of all-cause death, stroke, new-onset or worsening heart failure to hospitalization, and paroxysmal or persistent atrial fibrillation.

Results

Compared to the controls, both HTN and HCM participants had impaired LA reservoir function (εs) and conduit function (εe) with the different stage of LA booster pump dysfunction (εa). LA strain was more sensitive than LV longitudinal strain (GLS) for evaluate primary endpoint (εs: 33.9% ± 7.5 vs. 41.2% ± 14.3, p = 0.02; εe: 13.6% ± 6.2 vs. 17.4% ± 10.4, p = 0.03; εa: 20.2% ± 6.0 vs. 23.7% ± 8.8, p = 0.07; GLS: -19.4% ± 6.4 vs. -20.0% ± 6.8, p = 0.70, respectively). After a mean follow-up of 6.8 years, 23 patients reached primary endpoint. Cox regression analyses indicated impaired LA reservoir and booster pump strain were associated with clinical outcomes in patients at the early stage of HTN and HCM (p < 0.05).

Conclusions

CMR-FT-derived strain is a potential and robust tool in demonstrating impaired LA mechanics, quantifying LA dynamics and underlining the impacts on LA-LV coupling in patients with HTN and HCM without LA enlargement. The corresponding LA dysfunction is a promising metric to assess clinical implication and predict prognosis at the early stage, superior to GLS.

State-of-the-art myocardial strain by CMR feature tracking: clinical applications and future perspectives

Based on conventional cine sequences of cardiac magnetic resonance (CMR), feature tracking (FT) is an emerging tissue tracking technique that evaluates myocardial motion and deformation quantitatively by strain, strain rate, torsion, and dyssynchrony. It has been widely accepted in modern literature that strain analysis can offer incremental information in addition to classic global and segmental functional analysis. Furthermore, CMR-FT facilitates measurement of all cardiac chambers, including the relatively thin-walled atria and the right ventricle, which has been a difficult measurement to obtain with the reference standard technique of myocardial tagging. CMR-FT objectively quantifies cardiovascular impairment and characterizes myocardial function in a novel way through direct assessment of myocardial fiber deformation. The purpose of this review is to discuss the current status of clinical applications of myocardial strain by CMR-FT in a variety of cardiovascular diseases. KEY POINTS: • CMR-FT is of great value for differential diagnosis and provides incremental value for evaluating the progression and severity of diseases. • CMR-FT guides the early diagnosis of various cardiovascular diseases and provides the possibility for the early detection of myocardial impairment and additional information regarding subclinical cardiac abnormalities. • Direct assessment of myocardial fiber deformation using CMR-FT has the potential to provide prognostic information incremental to common clinical and CMR risk factors.

Cardiac Imaging for the Assessment of Left Atrial Mechanics Across Heart Failure Stages

The left atrium (LA) is emerging as a key element in the pathophysiology of several cardiac diseases due to having an active role in contrasting heart failure (HF) progression. Its morphological and functional remodeling occurs progressively according to pressure or volume overload generated by the underlying disease, and its ability of adaptation contributes to avoid pulmonary circulation congestion and to postpone HF symptoms. Moreover, early signs of LA dysfunction can anticipate and predict the clinical course of HF diseases before the symptom onset which, particularly, also applies to patients with increased risk of HF with still normal cardiac structure (stage A HF). The study of LA mechanics (chamber morphology and function) is moving from a research interest to a clinical application thanks to a great clinical, prognostic, and pathophysiological significance. This process is promoted by the technological progress of cardiac imaging which increases the availability of easy-to-use tools for clinicians and HF specialists. Two-dimensional (2D) speckle tracking echocardiography and feature tracking cardiac magnetic resonance are becoming essential for daily practice. In this context, a deep understanding of LA mechanics, its prognostic significance, and the available approaches are essential to improve clinical practice. The present review will focus on LA mechanics, discussing atrial physiology and pathophysiology of main cardiac diseases across the HF stages with specific attention to the prognostic significance. Imaging techniques for LA mechanics assessment will be discussed with an overlook on the dynamic (under stress) evaluation of the chamber.

Left Ventricular Strain Measurements Derived from MR Feature Tracking: A Head-to-Head Comparison of a Higher Temporal Resolution Method With a Conventional Method

BACKGROUND

Magnetic resonance feature tracking (MR-FT) is an imaging technique that quantifies both global and regional myocardial strain. Currently, conventional MR-FT provides a superior signal and contrast-to-noise ratio but has a relatively low temporal resolution. A higher temporal resolution MR-FT technique may provide improved results.

PURPOSE

To explore the impact of higher temporal resolution on left ventricular (LV) myocardial strain measurements using MR-FT.

STUDY TYPE

Prospective.

POPULATION

One hundred and fifty-three participants including five healthy subjects and patients with various cardiac diseases referred to MR for cardiac assessment.

FIELD STRENGTH

3 T, balanced steady-state free precession sequence with and without compressed sensing (temporal resolution: 10 msec and 40 msec, respectively).

ASSESSMENT

Conventional (40 msec) and higher (10 msec) temporal resolution data were acquired in all subjects during the same scanning session. Global circumferential strain (GCS), global longitudinal strain (GLS), and global radial strain (GRS) as well as peak systolic and diastolic strain rates (SRs) were measured by MR-FT and compared between the two temporal resolutions. We also performed subgroup analyses according to heart rates (HRs) and LV ejection fraction (LVEF).

STATISTICAL TESTS

Paired t-test, Wilcoxon signed-rank test, linear regression analyses, Bland-Altman plots. A P value <0.05 was considered to be statistically significant.

RESULTS

GCS and GRS were significantly higher in the 10-msec temporal resolution studies compared to the 40-msec temporal resolution studies (GCS: -13.00 ± 6.58% vs. -12.51 ± 5.76%; GRS: 21.97 ± 14.54% vs. 20.62 ± 12.52%). In the subgroup analyses, significantly higher GLS, GCS, and GRS values were obtained in subjects with LVEF ≥50%, and significantly higher GCS and GRS values were obtained in subjects with HRs <70 bpm when assessed with the 10-msec vs. the 40-msec temporal resolutions. All the peak systolic and diastolic SRs were significantly higher in the higher temporal resolution acquisitions. This was also true for all subgroups.

DATA CONCLUSIONS

Higher temporal resolution resulted in significantly higher cardiac strain and SR values using MR-FT and could be beneficial, particularly in patients with LVEF ≥50% and HR <70 bpm.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 1.