Left atrial strain: a multi-modality, multi-vendor comparison study

Normal Values for Atrial Deformation Measured by Feature-Tracking Cardiac MRI: A Meta-Analysis

BACKGROUND

A consensus on normal atrial deformation measurements by feature-tracking cardiac MRI remained absent.

PURPOSE

Provide reference ranges for atrial strain parameters in normal subjects, evaluating the influence of field strength and analysis software on the measurements.

STUDY TYPE

Meta-analysis.

POPULATION

2708 subjects from 42 studies undergoing cardiac MRI.

ASSESSMENT

A systematic search was conducted from database (PubMed, Web of Science, ScienceDirect, and EMBASE) inception through August 2023. The random-effects model was used to pool the means of biatrial strain parameters. Heterogeneity and clinical variable effects were assessed. Strain measurements among different field strengths and analysis software were compared.

STATISTICAL TESTS

The inverse-variance method, Cochrane Q statistic, and I2 value, meta-regression analysis, and ANOVA were used; P < 0.05 was considered statistically significant.

RESULTS

The pooled means of left atrial (LA) total strain (εs), passive strain (εe), and active strain (εa) were 37.46%, 22.73%, and 16.24%, respectively, and the pooled means of LA total strain rate (SRs), passive strain rate (SRe), and active strain rate (SRa) were 1.66, -1.95, and -1.83, indicating significant heterogeneity. The pooled means of right atrial (RA) εs, εe, and εa were 44.87%, 26.05%, and 18.83%. RA SRs, SRe, and SRa were 1.66, -1.95, and -1.83, respectively. The meta-regression identified age as significantly associated with LA εs, εe and SRe, field strength was associated with LA SRa (all P < 0.05). ANOVA revealed differences in LA εa and SRa among different analysis software and in LA εs and all LA strain rates (all P < 0.05) among field strengths. No significant differences were identified in RA strain across analysis software (RA strain: P = 0.145-0.749; RA strain rates: P = 0.073-0.744) and field strengths (RA strain: P = 0.641-0.794; RA strain rates: P = 0.204-0.458).

DATA CONCLUSION

This study demonstrated the pooled reference values of biatrial strain. Age, analysis software, and field strength were attributed to differences in LA strain, whereas RA strain showed consistency across different field strengths and analysis software. Limited study subjects may account for the absence of influence on RA strain.

LEVEL OF EVIDENCE: 1

TECHNICAL EFFICACY

Stage 5.

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.

Impact of temporal and spatial resolution on atrial feature tracking cardiovascular magnetic resonance imaging

BACKGROUND

Myocardial deformation assessment by cardiovascular magnetic resonance-feature tracking (CMR-FT) has incremental prognostic value over volumetric analyses. Recently, atrial functional analyses have come to the fore. However, to date recommendations for optimal resolution parameters for accurate atrial functional analyses are still lacking.

METHODS

CMR-FT was performed in 12 healthy volunteers and 9 ischemic heart failure (HF) patients. Cine sequences were acquired using different temporal (20, 30, 40 and 50 frames/cardiac cycle) and spatial resolution parameters (high 1.5 × 1.5 mm in plane and 5 mm slice thickness, standard 1.8 × 1.8 × 8 mm and low 3.0 × 3.0 × 10 mm). Inter- and intra-observer reproducibility were calculated.

RESULTS

Increasing temporal resolution is associated with higher absolute strain and strain rate (SR) values. Significant changes in strain assessment for left atrial (LA) total strain occurred between 20 and 30 frames/cycle amounting to 2,5-4,4% in absolute changes depending on spatial resolution settings. From 30 frames/cycle onward, absolute strain values remained unchanged. Significant changes of LA strain rate assessment were observed up to the highest temporal resolution of 50 frames/cycle. Effects of spatial resolution on strain assessment were smaller. For LA total strain a general trend emerged for a mild decrease in strain values obtained comparing the lowest to the highest spatial resolution at temporal resolutions of 20, 40 and 50 frames/cycle (p = 0.006-0.046) but not at 30 frames/cycle (p = 0.140).

CONCLUSION

Temporal and to a smaller extent spatial resolution affect atrial functional assessment. Consistent strain assessment requires a standard spatial resolution and a temporal resolution of 30 frames/cycle, whilst SR assessment requires even higher settings of at least 50 frames/cycle.

Left Atrial and Ventricular Strain Differentiates Cardiac Amyloidosis and Hypertensive Heart Disease: A Cardiac MR Feature Tracking Study

RATIONALE AND OBJECTIVES

Strain measured by feature tracking technique represents the degree of deformation and reflects the systolic and diastolic function of the heart. Our purpose was to evaluate the differential diagnostic value and correlations of left atrial (LA) strain (LAS) and left ventricular (LV) strain (LVS) in cardiac amyloidosis (CA) and hypertensive heart disease (HHD) patients.

MATERIALS AND METHODS

We recruited 25 CA patients, 30 sex- and age-matched HHD patients and 20 healthy subjects totally. LAS and LVS were analyzed by CVI42 post-processing software. The efficiency of LAS and LVS in differentiating CA from HHD was compared by receiver operating characteristic curves analysis. Pearson or Spearman's analysis were used to assess the correlation between LAS and LV parameters.

RESULTS

Both HHD and CA patients had impaired LVS, the gradient of increasing absolute values of longitudinal strain (LS) and radial strain (RS) from the basal to the apical myocardium was most pronounced in the CA group, its relative apical sparing of LS (RASLS) ratio reached 0.91 ± 0.02, significantly higher than other two groups (HHD: 0.72 ± 0.02; controls: 0.56 ± 0.01, all p <0.001). Additionally, except for the booster strain in the HHD group was preserved, all other LAS were reduced in patients' groups. The RASLS had the best differential diagnostic efficacy with an area under the curve (AUC) of 0.930 (p <0.001); The AUCs of LAS all greater than 0.850, above global LS (GLS) (AUC = 0.770, p = 0.001). LAS was notably correlated with LV ejection fraction (LVEF) and GLS, with reservoir strain having the greatest correlation with GLS (r = -0.828, p <0.001).

CONCLUSION

The RASLS has high efficiency in guiding the differential diagnosis of CA and HHD with similar degree and presentation of LVH. Moreover, LAS values can also provide some useful information and they are closely linked with LV function, CMR feature tracking may provide assistance in the evaluation of LA-LV coupling.

Assessment of left atrioventricular coupling and left atrial function impairment in diabetes with and without hypertension using CMR feature tracking

PURPOSE

The study was designed to assess the effect of co-occurrence of diabetes mellitus (DM) and hypertension on the deterioration of left atrioventricular coupling index (LACI) and left atrial (LA) function in comparison to individuals suffering from DM only.

METHODS

From December 2015 to June 2022, we consecutively recruited patients with clinically diagnosed DM who underwent cardiac magnetic resonance (CMR) at our hospital. The study comprised a total of 176 patients with DM, who were divided into two groups based on their blood pressure status: 103 with hypertension (DM + HP) and 73 without hypertension (DM-HP). LA reservoir function (reservoir strain (εs), total LA ejection fraction (LAEF)), conduit function (conduit strain (εe), passive LAEF), booster-pump function (booster strain (εa) and active LAEF), LA volume index (LAVI), LV global longitudinal strain (LVGLS), and LACI were evaluated and compared between the two groups.

RESULTS

After adjusting for age, sex, body surface area (BSA), and history of current smoking, total LAEF (61.16 ± 14.04 vs. 56.05 ± 12.72, p = 0.013) and active LAEF (43.98 ± 14.33 vs. 38.72 ± 13.51, p = 0.017) were lower, while passive LAEF (33.22 ± 14.11 vs. 31.28 ± 15.01, p = 0.807) remained unchanged in the DM + HP group compared to the DM-HP group. The DM + HP group had decreased εs (41.27 ± 18.89 vs. 33.41 ± 13.94, p = 0.006), εe (23.69 ± 12.96 vs. 18.90 ± 9.90, p = 0.037), εa (17.83 ± 8.09 vs. 14.93 ± 6.63, p = 0.019), and increased LACI (17.40±10.28 vs. 22.72±15.01, p = 0.049) when compared to the DM-HP group. In patients with DM, multivariate analysis revealed significant independent associations between LV GLS and εs (β=-1.286, p < 0.001), εe (β=-0.919, p < 0.001), and εa (β=-0.324, p = 0.036). However, there was no significant association observed between LV GLS and LACI (β=-0.003, p = 0.075). Additionally, hypertension was found to independently contribute to decreased εa (β=-2.508, p = 0.027) and increased LACI in individuals with DM (β = 0.05, p = 0.011).

CONCLUSIONS

In DM patients, LV GLS showed a significant association with LA phasic strain. Hypertension was found to exacerbate the decline in LA booster strain and increase LACI in DM patients, indicating potential atrioventricular coupling index alterations.

Impact of body mass index on worsening of diastolic function and impairment of left atrial strain in the general female urban population: a subanalysis of the Berlin female risk evaluation echocardiography follow-up study

Background

The association of body mass index (BMI) with diastolic dysfunction (DD) is well described in the literature. However, there is conflicting evidence and long-term follow-up data regarding effects of BMI on preclinical DD and left atrial (LA) function are scarce, highlighting the importance of early detection tools, such as myocardial strain.

Purpose

The aim of our study was to prospectively analyze the impact of clinical and demographic parameters, especially of BMI, on worsening of diastolic function and left atrial strain (LAS) in an urban population of women with a low prevalence of cardiovascular risk factors.

Methods and Results

An extensive clinical and echocardiographic assessment comprising the analysis of phasic LAS using two-dimensional speckle-tracking echocardiography (2D STE) was performed in 258 participants of the Berlin Female Risk Evaluation (BEFRI) trial between October 2019 and December 2020 after a mean follow-up period of 6.8 years. We compared clinical and echocardiographic parameters stratifying women by BMI < or ≥25 kg/m2, and we analyzed the impact of demographic characteristics on the worsening of DD and LA mechanics in the longer-term follow-up using univariate and multivariate regression analyses. 248 women were suitable for echocardiographic analysis of LAS using 2D STE. After a mean follow-up time of 6.8 years, LA reservoir strain (LASr) and LA conduit strain (LAScd) were significantly reduced in participants with a BMI ≥25 kg/m2 compared with women with a BMI <25 kg/m2 at baseline (30 ± 8% vs. 38 ± 9%, p < 0.0001; -14 ± 7% vs. -22 ± 8%, p < 0.0001). 28% of the overweighted women presented a deterioration of diastolic function at the time of follow-up in contrast with only 7% of the group with a BMI <25 kg/m2 (p < 0.0001). BMI remained significantly associated with LAS reductions after adjustment for other risk factors in multivariate regression analyses.

Conclusion

Overweight and obesity are related to impaired LAS and to a worsening of diastolic function after a long-term follow-up in a cohort of randomly selected women.

Impact of myocardial deformation on risk prediction in patients following acute myocardial infarction

Background

Strain analyses derived from cardiovascular magnetic resonance-feature tracking (CMR-FT) provide incremental prognostic benefit in patients sufferring from acute myocardial infarction (AMI). This study aims to evaluate and revalidate previously reported prognostic implications of comprehensive strain analyses in a large independent cohort of patients with ST-elevation myocardial infarction (STEMI).

Methods

Overall, 566 STEMI patients enrolled in the CONDITIONING-LIPSIA trial including pre- and/or postconditioning treatment in addition to conventional percutaneous coronary intervention underwent CMR imaging in median 3 days after primary percutaneous coronary intervention. CMR-based left atrial (LA) reservoir (Es), conduit (Ee), and boosterpump (Ea) strain analyses, as well as left ventricular (LV) global longitudinal strain (GLS), circumferential strain (GCS), and radial strain (GRS) analyses were carried out. Previously identified cutoff values were revalidated for risk stratification. Major adverse cardiac events (MACE) comprising death, reinfarction, and new congestive heart failure were assessed within 12 months after the occurrence of the index event.

Results

Both atrial and ventricular strain values were significantly reduced in patients with MACE (p < 0.01 for all). Predetermined LA and LV strain cutoffs enabled accurate risk assessment. All LA and LV strain values were associated with MACE on univariable regression modeling (p < 0.001 for all), with LA Es emerging as an independent predictor of MACE on multivariable regression modeling (HR 0.92, p = 0.033). Furthermore, LA Es provided an incremental prognostic value above LVEF (a c-index increase from 0.7 to 0.74, p = 0.03).

Conclusion

External validation of CMR-FT-derived LA and LV strain evaluations confirmed the prognostic value of cardiac deformation assessment in STEMI patients. In the present study, LA strain parameters especially enabled further risk stratification and prognostic assessment over and above clinically established risk parameters.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT02158468.

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.

Atrial cardiomyopathy: Current and future imaging methods for assessment of atrial structure and function

Changes in atrial size and function have historically been considered a surrogate marker of ventricular dysfunction. However, it is now recognized that atrial cardiomyopathy (ACM) may also occur as a primary myocardial disorder. Emerging evidence that ACM is a major risk factor for atrial fibrillation, heart failure, and thromboembolic stroke, has highlighted the significance of this disorder and the need for better assessment of atrial metrics in clinical practice. Key barriers in this regard include a lack of standardized criteria or hierarchy for the diagnosis of ACM and lack of consensus for the most accurate phenotyping methods. In this article we review existing literature on ACM, with a focus on current and future non-invasive imaging methods for detecting abnormalities of atrial structure and function. We discuss the relative advantages and disadvantages of transthoracic echocardiography and cardiac magnetic resonance imaging for assessing a range of parameters, including atrial size and contractile function, strain, tissue characteristics, and epicardial adipose tissue. We will also present the potential application of novel imaging methods such as sphericity index and four- or five-dimensional flow.

Left atrial function evaluation by 2D speckle-tracking echocardiography in patients with vasovagal syncope

OBJECTIVES

Evidence indicates left atrial (LA) involvement in vasovagal syncope (VVS). The LA regulates left ventricular filling during the cardiac cycle. We aimed to assess LA function in patients with VVS by 2D speckle-tracking echocardiography.

METHODS

Sixty-nine consecutive patients with VVS were recruited. Based on the head-up tilt test (HUTT) results, the study population was divided into two groups: HUTT+ (n = 45) and HUTT- (n = 24). Fifty-one consecutive subjects were enrolled as the control group. LA myocardial deformation parameters were measured by 2D speckle-tracking echocardiography to evaluate LA function.

RESULTS

Maximal, minimal, and pre-P LA volumes were lower in patients with VVS. Strain and strain rate during reservoir, conduit, and contraction phases in VVS patients with HUTT+ or HUTT- were not statistically significantly different from those in the control group. Additionally, the volumetric parameters of LA function showed no difference in statistical significance between the three study groups.

CONCLUSIONS

While LA phasic function was not different between the two groups of VVS patients with HUTT+ or HUTT- and the control group, LA size during the three LA phases was smaller in patients with VVS.

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.

Prognostic Significance of Cardiac Magnetic Resonance in Left Atrial and Biventricular Strain Analysis during the Follow-Up of Suspected Myocarditis

To assess the variation in left atrial (LA) and biventricular strain and its prognostic value in the course of suspected myocarditis, this retrospective study included 55 patients with clinically suspected myocarditis who underwent cardiac magnetic resonance (CMR) examinations at baseline and follow-up periods. Cine images were used for feature tracking analysis. Paired Student's t test, McNemar's test, and Cox proportional hazard regression were used for statistical analysis. The LA total emptying fraction was the only functional index that showed a statistically significant improvement. The initial LA peak's late negative strain rate (SRa) was the only parameter with a significant predictive power of major adverse cardiac events under univariable (hazard ratio [HR] 2.396, 95% confidence interval [CI] 1.044-5.498, p = 0.039) and multivariable Cox survival analysis when adjusted by LA strain parameters (HR 5.072, 95% CI 1.478-17.404, p = 0.010), LA strain and functional parameters (HR 7.197, 95% CI 1.679-30.846, p = 0.008), and LA and biventricular strain and functional parameters (HR 10.389, 95% CI 2.250-47.977, p = 0.003). Thus, our findings indicate that CMR strain is useful for monitoring LA and ventricular function in suspected myocarditis, that LA function may recover preceding ventricular function changes, and that LA strain may serve as an incremental tool to predict adverse outcomes.

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.

The year 2021 in the European Heart Journal—Cardiovascular Imaging: Part I

The European Heart Journal—Cardiovascular Imaging was introduced in 2012 and has during these 10 years become one of the leading multimodality cardiovascular imaging journals. The journal is currently ranked as Number 19 among all cardiovascular journals. It has an impressive impact factor of 9.130 and our journal is well established as one of the top cardiovascular journals. The most important studies published in our Journal in 2021 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

Left Atrial Cardiomyopathy - A Challenging Diagnosis

Left atrial cardiomyopathy (LACM) has been an ongoing focus of research for several years. There is evidence that LACM is responsible for atrial fibrillation and embolic strokes of undetermined sources. Therefore, the correct diagnosis of LACM is of clinical importance. Various techniques, including electrocardiography, echocardiography, cardiac magnetic resonance imaging, computed tomography, electroanatomic mapping, genetic testing, and biomarkers, can both identify and quantify structural, mechanical as well as electrical dysfunction in the atria. However, the question arises whether these techniques can reliably diagnose LACM. Because of its heterogeneity, clinical diagnosis is challenging. To date, there are no recommendations for standardized diagnosis of suspected LACM. However, standardization could help to classify LACM more precisely and derive therapeutic directions to improve individual patient management. In addition, uniform diagnostic criteria for LACM could be important for future studies. Combining several parameters and relating them seems beneficial to approach the diagnosis of LACM. This review provides an overview of the current evidence regarding the diagnosis of LACM, in which several potential parameters are discussed and, consequently, a proposal for a diagnostic algorithm is presented.

Multi-parametric analyses to investigate dependencies of normal left atrial strain by cardiovascular magnetic resonance feature tracking

Left-atrial (LA) strain is the result of complex hemodynamics, which may be better characterized using a multiparametric approach. Cardiovascular magnetic resonance (CMR) feature tracking was used to perform a comprehensive LA strain assessment of 183 enrolled healthy volunteers (11–70 years, 97 females, median 32.9 ± 28.3 years). Novel strain dependencies were assessed using multi-parametric regression (MPR) analyses. LA volumetric data, left ventricular strain, transmitral and pulmonary venous blood flow parameters were utilized to create clusters for MPR of all subjects and a heart rate controlled subgroup (pulse: 60–75/min, N = 106). The LA reservoir(r) and conduit(c) strains of the total cohort were significantly elevated (p ≤ 0.001) in women (r: 49.7 ± 12.9%, c: 32.0 ± 11.0%) compared to men (r: 42.9 ± 11.4%, c: 26.1 IQ 10.5%). In contrast, there were no gender-specific differences (p > 0.05) for subgroup LA reservoir, conduit and booster(b) strains (all, r: 47.3 ± 12.7%; c: 29.0 IQ 15.5%; b: 17.6 ± 5.4%) and strain rates (all, 2.1 IQ 1.0 s⁻¹; − 2.9 IQ 1.5 s⁻¹; − 2.3 IQ 1.0 s⁻¹). MPR found large effect sizes (|R²|≥ 0.26) for correlations between strain and various cardiac functional parameters. Largest effect size was found for the association between LA conduit strain and LA indexed booster volume, LA total ejection fraction, left ventricular global radial strain and E-wave (|R²|= 0.437). In addition to providing normal values for sex-dependent LA strain and strain rate, no gender differences were found with modified heart rate. MPR analyses of LA strain/strain rate and various cardiac functional parameters revealed that heart rate control improved goodness-of-fit for the overall model.

Comparison of left atrial strain by feature-tracking cardiac magnetic resonance with speckle-tracking transthoracic echocardiography

Left atrial (LA) strain is a novel non-invasive parameter for assessing LA hemodynamics and function. We sought to compare the intermodality differences between transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) derived LA strain, as well as reproducibility of strain measurements. We evaluated 70 subjects (mean age 42.1 ± 17 years, 44% males) with no significant cardiovascular disease who underwent both CMR and TTE within 6 months of each other. LA strain measurements i.e. reservoir strain (ƐR), conduit strain (ƐCD), and contractile strain (ƐCT), were compared using speckle-tracking echocardiography (STE) and CMR feature tracking (CMR-FT). Correlation and systematic bias between modalities was evaluated using intraclass correlation coefficient (ICC) and proportional bias. TTE was performed before CMR with a median duration of 33 days (IQR 14-69 days). ICC for ƐR, ƐCT, ƐCD was 0.66 (95% CI 0.44-0.79), 0.63 (95% CI 0.4-0.77) and 0.56 (95% CI 0.3-0.73) respectively. There was evidence of systematic bias between modalities, on average LA volume was found to be 19% higher on CMR than TTE. Strain values were also higher by CMR-FT compared to STE with mean difference of 9.9 ± 12 (26.1%), 3.1 ± 5.5 (21.9%), 4.0 ± 9.9 (16.6%) for ƐR, ƐCT and ƐCD respectively. Regression showed proportional bias for both ƐR, and ƐCT (beta 0.76, 0.54 respectively; P < 0.0001). There were modest differences in intraobserver reproducibility between both modalities with better reproducibility for STE compared to CMR-FT. There was a modest intermodality correlation between STE and CMR-FT derived LA strain components. There were systematic differences and proportional bias in measurements between modalities. These differences should be considered when interpreting LA strain using either modality.

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.

Left atrial reservoir strain is an outstanding predictor of adverse cardiovascular outcomes in patients undergoing maintenance hemodialysis: Assessment via three-dimensional speckle tracking echocardiography

Background

There is a paucity of literature focusing left atrium (LA) in patients undergoing maintenance hemodialysis (MHD).

Hypothesis

We used three‐dimensional speckle tracking echocardiography (3DSTE) to evaluate LA in MHD patients and to explore its predictive value for adverse outcomes.

Methods

Echocardiography was performed on 130 consecutively enrolled MHD patients without previous cardiac diseases. Conventional and 3DSTE parameters of LA were obtained. The MHD cohort was then followed and the end point was major adverse cardiovascular events (MACEs). LA strain indices, including reservoir strain (LASr), conduit strain (LAScd), and contractile strain (LASct), were measured and compared between patients with and without MACEs.

Results

Patients were prospectively followed up for a median of 40.5 (interquartile range: 26.3–48.0) months. During follow‐up, 43 patients met the end point. These patients had larger LA size and reduced LA strains (LA maximal volume indexed: 45.1 ± 11.9 vs. 33.8 ± 6.9ml/m²; LASr: 20.2 ± 3.5 vs. 27.2 ± 3.3%; LAScd: −12.3 ± 5.2 vs. −14.5±4.0%; LASct: −8.0 ± 4.2 vs. −13.2 ± 3.7%; all p<.05), compared with those without MACEs. Multivariable regression analysis showed LASr was the strongest predictor of MACEs (hazard ratio, 0.69; 95% confidence interval, 0.54–0.89; p=.004). Univarite Kaplan–Meier analysis revealed the incidence of MACEs in the impaired LASr (<24.2%) group was significantly higher than in the normal LASr group (log rank p<.001).

Conclusions

LASr derived from 3DSTE is an independent predictor of MACEs and cardiac death in MHD patients, superior to LV parameters and LA volume indices.

Sleep-Disordered Breathing Is Associated With Reduced Left Atrial Strain Measured by Cardiac Magnetic Resonance Imaging in Patients After Acute Myocardial Infarction

Aims

Sleep disordered breathing (SDB) is known to cause left atrial (LA) remodeling. However, the relationship between SDB severity and LA dysfunction is insufficiently understood and may be elucidated by detailed feature tracking (FT) strain analysis of cardiac magnetic resonance images (CMR). After myocardial infarction (MI), both the left ventricle and atrium are subjected to increased stress which may be substantially worsened by concomitant SDB that could impair consequential healing. We therefore analyzed atrial strain in patients at the time of acute MI and 3 months after.

Methods and Results

40 patients with acute MI underwent CMR and polysomnography (PSG) within 3–5 days after MI. Follow-up was performed 3 months after acute MI. CMR cine data were analyzed using a dedicated FT software. Atrial strain (ε) and strain rate (SR) for atrial reservoir ([ε_s]; [SR_s]), conduit ([ε_e]; [SR_e]) and booster function ([ε_a]; [SR_a]) were measured in two long-axis views. SDB was defined by an apnea-hypopnea-index (AHI) ≥15/h. Interestingly, LA ε_s and ε_e were significantly reduced in patients with SDB and correlated negative with AHI as a measure of SDB severity at both baseline and follow-up. Intriguingly, patients that exhibited a reduced AHI at follow-up were more likely to have developed improved atrial reservoir and conduit strain (linear regression, p=0.08 for ε_s and ε_e). Patients with improved SDB (ΔAHI < −5/h) exhibited a mean improvement of LA reservoir strain of +7.2 ± 8.4% whereas patients with SDB deterioration (ΔAHI> + 5/h) showed a mean decrease of −5.3 ± 11.0% (p = 0.0131). Similarly, the difference for LA conduit function was +4.8 ± 5.9% (ΔAHI < −5/h) vs −3.6 ± 8.8% (ΔAHI> +5/h). Importantly, conventional volumetric parameters for atrial function (LA area, LA volume index) did not correlate with AHI at baseline or follow-up.

Conclusion

Our results show that LA function measured by CMR strain but not by volumetry is impaired in patients with SDB during acute cardiac injury. Consistent with a mechanistic association, improvement of SBD at follow-up resulted in improved LA strain. LA strain measurement might thus provide insight into atrial function in patients with SDB.

Association of left atrial strain by cardiovascular magnetic resonance with recurrence of atrial fibrillation following catheter ablation

BACKGROUND

Atrial fibrillation (AF) is a progressive condition, which is characterized by inflammation/fibrosis of left atrial (LA) wall, an increase in the LA size/volumes, and decrease in LA function. We sought to investigate the relationship of anatomical and functional parameters obtained by cardiovascular magnetic resonance (CMR), with AF recurrence in paroxysmal AF (pAF) patients after catheter ablation.

METHODS

We studied 80 consecutive pAF patients referred for ablation, between January 2014 and December 2019, who underwent pre- and post-ablation CMR while in sinus rhythm. LA volumes were measured using the area-length method and included maximum, minimum, and pre-atrial-contraction volumes. CMR-derived LA reservoir strain (ℇR), conduit strain (ℇCD), and contractile strain (ℇCT) were measured by computer assisted manual planimetry. We used a multivariate logistical regression to estimate the independent predictors of AF recurrence after ablation.

RESULTS

Mean age was 58.6 ± 9.4 years, 75% men, mean CHA2DS2-VASc score was 1.7, 36% had prior cardioversion and 51% were taking antiarrhythmic drugs. Patients were followed for a median of 4 years (Q1-Q3 = 2.5-6.2 years). Of the 80 patients, 21 (26.3%) patients had AF recurrence after ablation. There were no significant differences between AF recurrence vs. no recurrence groups in age, gender, CHA2DS2-VASc score, or baseline comorbidities. At baseline, patients with AF recurrence compared to without recurrence had lower LV end systolic volume index (32 ± 7 vs 37 ± 11 mL/m2; p = 0.045) and lower ℇCT (7.1 ± 4.6 vs 9.1 ± 3.7; p = 0.05). Post-ablation, patients with AF recurrence had higher LA minimum volume (68 ± 32 vs 55 ± 23; p = 0.05), right atrial volume index (62 ± 20 vs 52 ± 19 mL/m2; p = 0.04) and lower LA active ejection fraction (24 ± 8 vs 29 ± 11; p = 0.05), LA total ejection fraction (39 ± 14 vs 46 ± 12; p = 0.02), LA expansion index (73.6 ± 37.5 vs 94.7 ± 37.1; p = 0.03) and ℇCT (6.2 ± 2.9 vs 7.3 ± 1.7; p = 0.04). Adjusting for clinical variables in the multivariate logistic regression model, post-ablation minimum LA volume (OR 1.09; CI 1.02-1.16), LA expansion index (OR 0.98; CI 0.96-0.99), and baseline ℇR (OR 0.92; CI 0.85-0.99) were independently associated with AF recurrence.

CONCLUSION

Significant changes in LA volumes and strain parameters occur after AF ablation. CMR derived baseline ℇR, post-ablation minimum LAV, and expansion index are independently associated with AF recurrence.

Normal values and reference ranges for left atrial strain by speckle-tracking echocardiography: the Copenhagen City Heart Study

AIMS 

Left atrial (LA) function assessed by two-dimensional speckle-tracking echocardiography has shown increasing clinical and prognostic significance. We sought to establish age- and sex-based normative values of LA strain in the general population and to assess the prognostic yield of lower limits of normality of LA strain in relation to future atrial fibrillation (AF).

METHODS AND RESULTS 

We determined normative values of peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA strain during the conduit phase (LACS) in 1641 healthy participants included in the fifth Copenhagen City Heart Study. In a secondary analysis, a validation cohort of 2016 participants, regardless of health status, were included to assess the prognostic value of the established reference values. In the healthy cohort, median age was 46 years (interquartile range 32-57), 62% were female. Median PALS, PACS, and LACS and corresponding limits of normality in the healthy participants were 39.4% (23.0-67.6%), 15.5% (6.4-28.0%), and 23.7% (8.8-44.8%), respectively. There was a tendency of lower values of PALS and LACS in males and older participants, while PACS tended to increase with advancing age. The established lower limits of normality showed high specificity (range 93-94%) regarding future AF, implying a low risk of developing AF in participants with LA strain above the lower limits of normality in their respective sex and age group.

CONCLUSION 

We report normal values for LA strain stratified by sex and age. The lower limits of normality showed high specificity regarding future AF.

Left atrial evaluation by cardiovascular magnetic resonance: sensitive and unique biomarkers

Left atrial (LA) imaging is still not routinely used for diagnosis and risk stratification, although recent studies have emphasized its importance as an imaging biomarker. Cardiovascular magnetic resonance is able to evaluate LA structure and function, metrics that serve as early indicators of disease, and provide prognostic information, e.g. regarding diastolic dysfunction, and atrial fibrillation (AF). MR angiography defines atrial anatomy, useful for planning ablation procedures, and also for characterizing atrial shapes and sizes that might predict cardiovascular events, e.g. stroke. Long-axis cine images can be evaluated to define minimum, maximum, and pre-atrial contraction LA volumes, and ejection fractions (EFs). More modern feature tracking of these cine images provides longitudinal LA strain through the cardiac cycle, and strain rates. Strain may be a more sensitive marker than EF and can predict post-operative AF, AF recurrence after ablation, outcomes in hypertrophic cardiomyopathy, stratification of diastolic dysfunction, and strain correlates with atrial fibrosis. Using high-resolution late gadolinium enhancement (LGE), the extent of fibrosis in the LA can be estimated and post-ablation scar can be evaluated. The LA LGE method is widely available, its reproducibility is good, and validations with voltage-mapping exist, although further scan-rescan studies are needed, and consensus regarding atrial segmentation is lacking. Using LGE, scar patterns after ablation in AF subjects can be reproducibly defined. Evaluation of 'pre-existent' atrial fibrosis may have roles in predicting AF recurrence after ablation, predicting new-onset AF and diastolic dysfunction in patients without AF. LA imaging biomarkers are ready to enter into diagnostic clinical practice.

Association Between Heart Failure With Preserved Left Ventricular Ejection Fraction and Impaired Left Atrial Phasic Function in Hypertrophic Cardiomyopathy: Evaluation by Cardiac MRI Feature Tracking

BACKGROUND

The majority of heart failure (HF) in hypertrophic cardiomyopathy (HCM) manifests as a phenotype with preserved left ventricular (LV) ejection fraction; however, the exact contribution of left atrial (LA) phasic function to HF with preserved ejection fraction (HFpEF) in HCM remains unresolved.

PURPOSE

To define the association between LA function and HFpEF in HCM patients using cardiac magnetic resonance imaging (MRI) feature tracking.

STUDY TYPE

Retrospective.

POPULATION

One hundred and fifty-four HCM patients (HFpEF vs. non-HF: 55 [34 females] vs. 99 [43 females]).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession.

ASSESSMENT

LA reservoir function (reservoir strain [ε_s ], total ejection fraction [EF]), conduit function (conduit strain [ε_e ], passive EF), booster-pump function (booster strain [ε_a ] and active EF), LA volume index, and LV global longitudinal strain (LV GLS) were evaluated in HCM patients.

STATISTICAL TESTS

Chi-square test, Student's t-test, Mann-Whitney U test, multivariate linear regression, logistic regression, and net reclassification analysis were used. Two-sided P < 0.05 was considered statistically significant.

RESULTS

No significant difference was found in LV GLS between the non-HF and HFpEF group (-10.67 ± 3.14% vs. -10.14 ± 4.01%, P = 0.397), whereas the HFpEF group had more severely impaired LA phasic strain (ε_s : 27.40 [22.60, 35.80] vs. 18.15 [11.98, 25.90]; ε_e : 13.80 [9.20, 18.90] vs. 7.95 [4.30, 14.35]; ε_a : 13.50 [9.90, 17.10] vs. 7.90 [5.40, 14.15]). LA total EF (37.91 [29.54, 47.94] vs. 47.49 [39.18, 55.01]), passive EF (14.70 [7.41, 21.49] vs. 18.07 [9.32, 24.78]), and active EF (27.19 [17.79, 36.60] vs. 36.64 [26.63, 42.71]) were all significantly decreased in HFpEF patients compared with non-HF patients. LA reservoir (β = 0.90 [0.85, 0.96]), conduit (β = 0.93 [0.87, 0.99]), and booster (β = 0.86 [0.78, 0.95]) strain were independently associated with HFpEF in HCM patients. The model including reservoir strain (Net Reclassification Index [NRI]: 0.260) or booster strain (NRI: 0.325) improved the reclassification of HFpEF based on LV GLS and minimum left atrial volume index (LAVI_min ).

DATA CONCLUSION

LA phasic function was severely impaired in HCM patients with HFpEF, whereas LV function was not further impaired compared with non-HF patients.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 3.

Impaired Relaxation and Reduced Lusitropic Reserve in Atrial Myocardium in the Obese Patients

Background: Obesity can influence the structure and function of the atrium, but most studies focused on the relationship of body mass index (BMI) and overt left atrium (LA) dysfunction as assessed by clinical imaging. We combined the assessment of right atrium (RA) function in vivo and in vitro in obese and non-obese patients scheduled for elective cardiac surgery.

Methods: Atrial structure and function were quantified pre-operatively by echocardiography. RA tissue removed for the establishment of extracorporeal support was collected and RA trabeculae function was quantified in vitro at baseline and with adrenergic stimulation (isoproterenol). Fatty acid-binding protein 3 (FABP3) was quantified in RA tissue. Results were stratified according to the BMI of the patients.

Results: About 76 patients were included pre-operatively for the echocardiographic analysis. RA trabeculae function at baseline was finally quantified from 46 patients and RA function in 28 patients was also assessed with isoproterenol. There was no significant correlation between BMI and the parameters of atrial function measured by the clinical echocardiography. However, in vitro measurements revealed a significant correlation between BMI and a prolonged relaxation of the atrial myocardium at baseline, which persisted after controlling for the atrial fibrillation and diabetes by the partial correlation analysis. Acceleration of relaxation with isoproterenol was significantly lower in the obese group (BMI ≥ 30 kg/m²). As a result, relaxation with adrenergic stimulation in the obese group remained significantly higher compared to the overweight group (25 kg/m² ≤ BMI < 30 kg/m², p = 0.027) and normal group (18.5 kg/m² ≤ BMI < 25 kg/m², p = 0.036). There were no differences on impacts of the isoproterenol on (systolic) developed force between groups. The expression of FABP3 in the obese group was significantly higher compared to the normal group (p = 0.049) and the correlation analysis showed the significant correlations between the level of FABP3 in the RA trabeculae function.

Conclusion: A higher BMI is associated with the early subclinical changes of RA myocardial function with the slowed relaxation and reduced adrenergic lusitropy.

Left Atrial Expansion Index for Noninvasive Estimation of Pulmonary Capillary Wedge Pressure: A Cardiac Catheterization Validation Study

BACKGROUND

Pulmonary capillary wedge pressure (PCWP) plays a pivotal role in cardiac disease diagnosis and management. Right heart catheterization (RHC) invasively provides accurate PCWP measurement, but it is impractical for widespread use in all patients. The left atrial expansion index (LAEI), measured on transthoracic echocardiography, describes the relative left atrial volume increase during the left atrial reservoir phase. The aim of this study was to validate LAEI as a noninvasive parameter for PCWP estimation.

METHODS

A total of 649 chronic cardiac patients (mean age, 66 ± 14 years; mean PCWP, 14 ± 7.6 mm Hg; mean left ventricular ejection fraction, 50 ± 15%) who underwent both clinically indicated RHC and transthoracic echocardiography within 24 hours were retrospectively enrolled. Patients were randomly divided into derivation (n = 509) and validation (n = 140) cohorts. PCWP was measured during RHC and defined as elevated when >12 mm Hg. Transthoracic echocardiographic parameters and LAEI were measured offline, blinded to RHC results.

RESULTS

In the derivation cohort, LAEI correlated logarithmically with PCWP, and the log-transformed LAEI (lnLAEI) correlated linearly with PCWP (r = -0.73, P < .001). lnLAEI showed an independent and additive predictive role for PCWP estimation over clinical and diastolic dysfunction (DD) parameters. The diagnostic accuracy of lnLAEI for elevated PCWP identification (area under the curve = 0.875, P < .001; optimal lnLAEI cutoff < 4.02) was higher than either the single DD parameters or their combination. In the validation cohort, lnLAEI cutoff < 4.02 showed higher accuracy than the 2016 DD algorithm (88% vs 74%) for elevated PCWP identification. Finally, the equation PCWP = 38.3 - 6.2 × lnLAEI, obtained from the derivation cohort, predicted invasively measured PCWP in the validation cohort.

CONCLUSIONS

In a cohort of patients with various chronic cardiac diseases, lnLAEI performed better than DD parameters and the 2016 DD algorithm for PCWP estimation. lnLAEI might be a useful echocardiographic parameter for noninvasive PCWP estimation.

Multi-modality assessment and role of left atrial function as an imaging biomarker in cardiovascular disease

The left atrium (LA) plays a vital role in maintaining normal cardiac function. LA volume and function have been utilised as important imaging biomarkers, with their prognostic value demonstrated in multiple cardiac conditions. More recently, there has been a sharp increase in the number of publications utilising LA strain by echocardiography and cardiac magnetic resonance (CMR) imaging. However, little is known about its prognostic value or reproducibility as a technique. In this review, we aim to highlight the conventional and novel imaging techniques available for LA assessment, using echocardiography and CMR, their role as an imaging biomarker in cardiovascular disease, the reproducibility of the techniques and the current limitations to their clinical application. We identify a need for further standardisation of techniques, with establishment of ‘normal’ cut-offs before routine clinical application can be made.

Reference Values for Left Atrial Strain and Strain Rate Based on a Large Sample of Healthy Chinese Adults: An MR-Feature Tracking Study

BACKGROUND

While reference values of left atrial (LA) deformation parameters in Western populations have been established, reference data in healthy Asian populations are limited.

PURPOSE

To establish age- and sex-specific reference values for LA strain and strain rate (SR) based on a large sample of healthy Chinese adults using magnetic resonance-feature tracking (MR-FT).

STUDY TYPE

Retrospective.

POPULATION

Four hundred and eight healthy Chinese adults (220 males, aged 43.5 ± 11.5 years; 188 females, aged 45.3 ± 12.8 years).

FIELD STRENGTH/SEQUENCE

1.5 T/balanced steady-state free precession.

ASSESSMENT

Reservoir strain (ε_s ), conduit strain (ε_e ), booster strain (ε_a ), peak positive SR (SRs), peak early negative SR (SRe), and peak late negative SR (SRa) were obtained by MR-FT.

STATISTICAL TESTS

We used Shapiro-Wilk test, Student's t-test, Mann-Whitney U-test, linear regression, and coefficient of determination (r² ).

RESULTS

Women demonstrated significantly greater LA strain (ε_s [%]: 44.0 ± 9.9 vs. 38.3 ± 8.7; ε_e [%]: 26.7 ± 8.0 vs. 22.3 ± 6.8; ε_a [%]: 17.3 ± 4.4 vs. 16.0 ± 3.8) and SR (SRs [/second]: 1.8 ± 0.5 vs. 1.6 ± 0.4; SRe [/second]: -2.5 ± 0.9 vs. -2.1 ± 0.7; SRa [/second]: -1.9 ± 0.6 vs. -1.8 ± 0.5) than men. For both sexes, aging was significantly associated with decreased ε_s , SRs, ε_e , and SRe (r²  = 0.07, r²  = 0.05, r²  = 0.19, and r²  = 0.24 for men; r²  = 0.13, r²  = 0.11, r²  = 0.31, and r²  = 0.46 for women), and significantly increased ε_a (r²  = 0.03 and r²  = 0.05 for men and women). There was no significant correlation between age and SRa in both sexes (P = 0.057 and P = 0.377 for men and women, respectively).

DATA CONCLUSION

We provide age- and sex-specific reference values for LA strain and SR based on a large sample of healthy Chinese adults using MR-FT.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 5.

Impairment of left atrial function in pediatric patients with repaired tetralogy of Fallot: a cardiovascular magnetic resonance imaging study

We aimed to assess left atrial (LA) strain before LA dilatation in patients with repaired tetralogy of Fallot (rTOF) compared with healthy controls. We also determined the effects of right atrial (RA) dilatation on LA performance using cardiovascular magnetic resonance-feature tracking (CMR-FT). Forty-nine pediatric patients with rTOF and 36 age- and sex-matched healthy controls were prospectively recruited between June 2017 and August 2019. Balanced steady-state free precession (2D b-SSFP) cine, 2D late gadolinium enhancement (LGE) and phase-contrast (PC) sequences were acquired on 1.5 and 3.0 Tesla scanners. Both ventricular and atrial volumes and ejection fraction were measured. Left ventricular (LV) strain and diastolic strain rates were evaluated between the rTOF patient and control groups. LA reservoir (Ɛs), conduit (Ɛe), and booster strain (Ɛa) were determined at LV end-systole, LV diastasis, and pre-LA systole, respectively. The first derivatives of the respective strains yielded corresponding peak strain rates. Statistical analysis was performed using the t-test and Mann-Whitney test for parametric and non-parametric variables, respectively. Correlations were assessed using Pearson's correlation coefficient for normally distributed variables and Spearman's correlation coefficient for non-parametric data. Intra-observer and inter-observer variabilities of LA strain and strain rate measurements were determined from ten randomly selected rTOF patients and ten control subjects. LA strain was significantly lower in patients with rTOF compared with controls (Ɛs, P < 0.001; Ɛe, P = 0.002; Ɛa, P < 0.001). The correlations between LA strain and RA stroke volume indices (SVi) and RA ejection fraction (EF) were moderate (Ɛs and SVi, r = 0.538, P < 0.001; Ɛs and RA EF, r = 0.493, P < 0.001; Ɛe and SVi, r = 0.532, P < 0.001; Ɛe and RA EF, r = 0.466, P < 0.001). LA strain and strain rates had good reproducibility in intra-observer and inter-observer analyses. LA strain and strain rates decreased in pediatric patients with rTOF compared with controls before LA enlargement. A dysfunction in LA performance might precede LV dysfunction in patients with rTOF, even in the early stages after repair.

Quantification of Myocardial Deformation Applying CMR-Feature-Tracking-All About the Left Ventricle?

Purpose of Review

Cardiac magnetic resonance-feature-tracking (CMR-FT)-based deformation analyses are key tools of cardiovascular imaging and applications in heart failure (HF) diagnostics are expanding. In this review, we outline the current range of application with diagnostic and prognostic implications and provide perspectives on future trends of this technique.

Recent Findings

By applying CMR-FT in different cardiovascular diseases, increasing evidence proves CMR-FT-derived parameters as powerful diagnostic and prognostic imaging biomarkers within the HF continuum partly outperforming traditional clinical values like left ventricular ejection fraction. Importantly, HF diagnostics and deformation analyses by CMR-FT are feasible far beyond sole left ventricular performance evaluation underlining the holistic nature and accuracy of this imaging approach.

Summary

As an established and continuously evolving technique with strong prognostic implications, CMR-FT deformation analyses enable comprehensive cardiac performance quantification of all cardiac chambers.

Compressed sensing acceleration of cardiac cine imaging allows reliable and reproducible assessment of volumetric and functional parameters of the left and right atrium

Objectives

To compare volumetric and functional parameters of the atria derived from highly accelerated compressed sensing (CS)–based cine sequences in comparison to conventional (Conv) cine imaging.

Methods

CS and Conv cine sequences were acquired in 101 subjects (82 healthy volunteers (HV) and 19 patients with heart failure with reduced ejection fraction (HFrEF)) using a 3T MR scanner in this single-center study. Time-volume analysis of the left (LA) and right atria (RA) were performed in both sequences to evaluate atrial volumes and function (total, passive, and active emptying fraction). Inter-sequence and inter- and intra-reader agreement were analyzed using correlation, intraclass correlation (ICC), and Bland-Altman analysis.

Results

CS-based cine imaging led to a 69% reduction of acquisition time. There was significant difference in atrial parameters between CS and Conv cine, e.g., LA minimal volume (LAVmin) (Conv 24.0 ml (16.7–32.7), CS 25.7 ml (19.2–35.2), p < 0.0001) or passive emptying fraction (PEF) (Conv 53.9% (46.7–58.4), CS 49.0% (42.0–54.1), p < 0.0001). However, there was high correlation between the techniques, yielding good to excellent ICC (0.76–0.99) and small mean of differences in Bland-Altman analysis (e.g. LAVmin − 2.0 ml, PEF 3.3%). Measurements showed high inter- (ICC > 0.958) and intra-rater (ICC > 0.934) agreement for both techniques. CS-based parameters (PEF AUC = 0.965, LAVmin AUC = 0.864) showed equivalent diagnostic ability compared to Conv cine imaging (PEF AUC = 0.989, LAVmin AUC = 0.859) to differentiate between HV and HFrEF.

Conclusion

Atrial volumetric and functional evaluation using CS cine imaging is feasible with relevant reduction of acquisition time, therefore strengthening the role of CS in clinical CMR for atrial imaging.

Key Points

• Reliable assessment of atrial volumes and function based on compressed sensing cine imaging is feasible.

• Compressed sensing reduces scan time and has the potential to overcome obstacles of conventional cine imaging.

• No significant differences for subjective image quality, inter- and intra-rater agreement, and ability to differentiate healthy volunteers and heart failure patients were detected between conventional and compressed sensing cine imaging.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-07830-z.

References Values for Left Atrial Volumes, Emptying Fractions, Strains, and Strain Rates and Their Determinants by Age, Gender, and Ethnicity: The Multiethnic Study of Atherosclerosis (MESA)

RATIONALE AND OBJECTIVES

Left Atrial (LA) adverse remodeling is an important predictor of morbidity and mortality in several cardiovascular (CV) diseases. Our goals were to quantify and provide reference ranges for LA structure and function using feature tracking cine cardiac magnetic resonance.

MATERIALS AND METHODS

2526 participants of the Multiethnic Study of Atherosclerosis study who had feature tracking cine cardiac magnetic resonance derived LA data and were free of atrial fibrillation/flutter and prior CV events at year five follow-up examination (2010-2012) were included in this study. LA phasic indexed volumes: maximum (LAVi max), minimum (LAVi min), and preatrial contraction (LAVi preA); LA empty fractions: total, passive, and active (LAtEF, LApEF, and LAaEF); LA longitudinal strain: maximum and preatrial contraction (S max and S preA); and LA longitudinal strain rate: systolic (SR max) and early/late diastolic (SR e and SR a) were measured. Age, gender, and race/ethnicity-specific reference ranges were identified. Also, reference values in a select subgroup of healthy participants free of traditional CV risk factors at the time of exam date were reported.

RESULTS

The mean ± SD for LAVi max, LAVi min, LAVi preA, S max, SR e, and SR a were in the 45-65-year-old participants: (33.8 ± 10 mL/m²), (14.5 ± 6.4 mL/m²), (24.8 ± 8.2 mL/m²), (34.6 ± 13.8 %), (-1.4 ± 0.7 s^-1), (-2.1 ± 1 s^-1) and in the ≥ 65-year-old participants: (35 ± 11.5 mL/m2), (16.6 ± 8.3 mL/m2), (27.6 ± 9.9 mL/m2), (31.2 ± 14.3 %), (-1 ± 0.6 s^-1), (-2.1 ± 1 s^-1) respectively. Younger individuals had Powered by Editorial Manager and ProduXion Manager from Aries Systems Corporation smaller LA volumes and better LA function compared to their older counterparts. Similar findings were observed in Chinese-Americans as compared to Whites.

CONCLUSION

This study provides reference values of LA structure and function parameters from a healthy multiethnic community-based population aged 53-94 years evaluated by FTMRI.

Left atrial function in diabetes: does it help?

Left atrial (LA) structural, functional and mechanical changes have important role in development of diabetic cardiomyopathy and it was discovered that LA remodeling has important prognostic role in the patients with diabetes (DM). Previously the focus of echocardiographic studies in DM population was on the left ventricular structure and function, but the atrioventricular coupling was proved to be one of the main predictors of cardiovascular morbidity and mortality in DM patients. Each phase of LA cycle has determinant role in the atrioventricular coupling and therefore the accurate assessment of LA phasic function gained importance over last decade. The failure of any of the three LA phasic functions (reservoir, conduit or contractile) leads potentially to LA dilatation, left ventricular diastolic dysfunction, atrial fibrillation and ultimately development of heart failure with preserved (or even reduced) ejection fraction. Even though LA phasic function has not been extensively studied in DM population, it is reasonable to hypothesize that LA dysfunction is very frequent in these patients, considering the high prevalence of atrial fibrillation and heart failure in these individuals. In research and clinical purposes two techniques have been used for determination of LA phasic function: volumetric and strain. Although these methods fundamentally differ, with their own advantages and limitations, they also provide comparable results that can direct our therapeutic approach in DM patients. Namely, not only that LA function represents an independent predictor of cardiovascular outcome in DM patients, but also it has been also associated with parameters of glycemic control. This review summarized the current knowledge regarding LA phasic function in DM patients.

Inter-vendor comparison of left atrial strain using layer specific strain analysis

Left atrial strain (LAS) on transthoracic echocardiogram (TTE) is increasingly recognised to have clinical utility in cardiovascular disease. Differences in LAS measurements between vendors remains a barrier for clinical use. We sought to compare LAS between two commonly used software platforms; the layer-specific endocardial and mid-myocardial measurements of LAS on General Electric (GE) Echopac were compared to TomTec strain. LAS was measured in 88 individuals with no previous cardiac history and 40 paroxysmal AF (PAF) patients, in sinus rhythm at TTE. Conventionally, LAS measured using GE Echopac is mid-myocardial strain (GE-mid); additionally, endocardial (GE-endo) LAS was evaluated. Both LAS measurements by GE were compared to TomTec-Arena (v2.30.02) measurements. Reservoir (ƐR), contractile (ƐCT) and conduit (ƐCD) phasic strain were evaluated. Both GE-mid and GE-endo LAS correlated well with TomTec LAS. On Bland-Altman analysis, GE-mid LAS measurements were systematically lower than TomTec LAS (ƐR: mean difference (MD) - 6.08%, limits of agreement (LOA) - 12%, 0%, ƐCT: MD - 0.8%, LOA - 7%, 5%, ƐCD: MD - 5.2% LOA - 12%, 1%). GE-endo LAS demonstrated no systematic difference from TomTec LAS, but had wider limits of agreement (ƐR: MD 0.41%, LOA - 7%, 8%, ƐCT: MD 0.50%, LOA - 6%, 7%, ƐCD: MD - 0.08%, LOA - 7%, 7%). ƐR had the best reproducibility. Mid-myocardial LAS, routinely evaluated by GE Echopac software, systematically underestimates LAS compared to TomTec. Using GE endocardial LAS eliminated this bias, but introduced greater variation between measurements. Serial measurements of LAS should therefore be performed on the same vendor system.

The year 2019 in the European Heart Journal - Cardiovascular Imaging: part II

The European Heart Journal - Cardiovascular Imaging was launched in 2012 and has during these years become one of the leading multimodality cardiovascular imaging journal. The journal is now established as one of the top cardiovascular journals and is the most important cardiovascular imaging journal in Europe. The most important studies published in our Journal from 2019 will be highlighted in two reports. Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease. While Part I of the review has focused on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging.

Left atrial function assessed by speckle tracking echocardiography in anthracycline-induced cardiotoxicity: a case report

Background

The onset prevention and early diagnosis in cardiotoxicity due to cancer chemotherapy are important, and it is important to detect cardiac dysfunction at an early stage and start treatment to enhance the therapeutic effect.

Case summary

A 31-year-old female with breast cancer received chemotherapy with epirubicin (400 mg/m²) and cyclophosphamide followed by docetaxel. Two months after the initiation of her chemotherapy, the left ventricular (LV) ejection fraction (LVEF) determined by echocardiography fell to 41.2%, and she was diagnosed with cancer therapy-related cardiac dysfunction (CTRCD). Three months after the initiation of cancer treatment, the peak velocity of late diastolic transmitral Doppler flow (A wave) became undetectable. Peak longitudinal strain (LS) and peak LS rate, which reflect left atrium (LA) reservoir function, gradually declined like the LVEF and LV-global LS (GLS). Seven months after the initiation of cancer treatment, she was diagnosed with acute decompensated heart failure. The changes in peak LS and peak LS at the onset were greater than those in LVEF and LV-GLS.

Discussion

This is a case report suggesting that LA reservoir function might be a more sensitive indicator than LVEF or LV-GLS in detecting CTRCD and that LA booster function might be the earliest. Left atrium reservoir function might be a more sensitive than conventional LV pump function and optimal indicator in CTRCD.

Assessment of long-term cardiac adaptation in adult patients with type II atrial septal defect : A cardiovascular magnetic resonance (CMR) study

OBJECTIVES

In type II atrial septal defect (ASD) patients, the left-to-right (LR) shunt causes adaptation of the heart and circulation. The study objective was to evaluate with cardiovascular magnetic resonance imaging (CMR) the impact of LR shunt on left (LV) and right ventricular (RV) volumes, function, and myocardial strain.

METHODS

Thirty-five patients (42 ± 17 years, 17 male) were compared to a control group (n = 40). Cine imaging was used to calculate ventricular volumes and ejection fraction (EF), global longitudinal (GLS) and circumferential strain (GCS), and longitudinal free wall (FWS) and interventricular septal (IVS) strain. Phase-contrast imaging was used to calculate pulmonary flow to systemic flow ratio (Qp/Qs).

RESULTS

The LR shunt (Qp/Qs 2.2 ± 0.6) resulted in larger RV end-diastolic volume (EDVi) (152 ± 42 vs 82 ± 11 ml/m²), lower LV EDVi (72 ± 16 vs 83 ± 9 ml/m²⁾, and higher RV/LV EDVi ratio (2.2 ± 0.5 vs 1.0 ± 0.1) than controls (all p < 0.001). Functionally, stroke volumes were larger in RV and lower in LV (both p < 0.001) with a strong trend toward lower RV EF in patients (p = 0.08). The LR shunt negatively impacted RV GLS (p = 0.03) but not RV GCS. Longitudinal IVS but not RV FWS were significantly lower in patients, i.e., p < 0.001, of longitudinal IVS. Shunt severity correlated with RV size and stroke volume, right atrial size, and pulmonary trunk diameter (all p < 0.001), but not with functional nor strain parameters.

CONCLUSION

Long-term cardiac adaptation in ASD patients, with RV overfilling and LV underfilling, has a negative impact on systolic RV performance, a phenomenon which likely can be attributed to longitudinal dysfunction of the interventricular septum.

KEY POINTS

• An LR shunt in type II ASD patients causes cardiac remodeling characterized by RV overfilling and conversely underfilling of the left ventricle. • At the long term, there is evidence of systolic dysfunction of the right ventricle in this group of patients. • Septal dysfunction underlies the observed impairment in RV function.