Left atrial function: physiology, assessment, and clinical implications

Structural phenotyping in atrial fibrillation with combined cardiac CT and atrial MRI: Identifying and differentiating individual structural remodelling types in AF

INTRODUCTION

Atrial remodelling (AR) is the persistent change in atrial structure and/or function and contributes to the initiation, maintenance and progression of atrial fibrillation (AF) in a reciprocal self-perpetuating relationship. Left atrial (LA) size, geometry, fibrosis, wall thickness (LAWT) and ejection fraction (LAEF) have all been shown to vary with pathological atrial remodelling. The association of these global remodelling markers with each other for differentiating structural phenotypes in AF is not well investigated.

METHOD

Patients referred for first-time AF ablation and controls without AF were prospectively recruited to undergo cardiac computed tomographic angiography (CCTA) and magnetic resonance imaging (MRI) with 3D atrial late-gadolinium enhanced (LGE) sequences. LAWT, atrial myocardial mass, LA volume and sphericity were calculated from CT. Biplane LA EF and LA fibrosis burden were derived from atrial MRI. Results were compared between patients with AF and controls.

RESULTS

Forty two AF patients (64.3% male, age 64.6 ± 10.2 years, CHA2DS2-VASc 2.48 ± 1.5, 69.0% paroxysmal AF, 31% persistent AF, LVEF 57.9 ± 10.5%) and 37 controls (64.9% male, age 56.6 ± 7.2, CHA2DS2-VASc 1.54 ± 1.1, LVEF 60.4 ± 4.9%) were recruited. Patients with AF had a significantly higher LAWT (1.45 ± 0.52 mm vs 1.12 ± 0.42 mm, p = 0.003), tissue mass (15.81 ± 6.53 g vs. 12.18 ± 5.01 g, p = 0.011), fibrosis burden (9.33 ± 8.35% vs 2.41 ± 3.60%, p = 0.013), left atrial size/volume (95.68 ± 26.63 mL vs 81.22 ± 20.64 mL, p = 0.011) and lower LAEF (50.3 ± 15.3% vs 65.2 ± 8.6%, p < 0.001) compared to controls. There was no significant correlation between % fibrosis with LAWT (p = 0.29), mass (p = 0.89), volume (p = 0.49) or sphericity (p = 0.79). LAWT had a statistically significant weak positive correlation with LA volume (r = 0.25, p = .041), but not with sphericity (p = 0.86). LAEF had a statistically significant but weak negative correlation with fibrosis (r = -0.33, p = 0.008) and LAWT (r = -0.24, p = 0.07).

CONCLUSION

AF is associated with significant quantifiable structural changes that are evident in LA size, tissue thickness, total LA tissue mass and fibrosis. These individual remodelling markers do not or only weakly correlate with each other suggesting different remodelling subtypes exist (e.g. fibrotic vs hypertrophic vs dilated). If confirmed, such a detailed understanding of the structural changes observed has the potential to inform clinical management strategies targeting individual mechanisms underlying the disease process.

Left Atrial Phasic Function Impairment in Subacute and Chronic Pulmonary Embolism Patients With Different Degrees of Obstruction: An MRI Feature Tracking Study

BACKGROUND

The alteration of left atrial (LA) phasic function in subacute and chronic pulmonary embolism (PE) patients is unclear.

PURPOSE

To investigate LA phasic strain and LA-right ventricular (RV) interaction in subacute and chronic PE patients with different degrees of obstruction by MRI-feature tracking (MRI-FT).

STUDY TYPE

Retrospective.

POPULATION

One hundred three PE patients (54 subacute [2 weeks to 3 months after initial symptoms], 49 chronic [>3 months after initial symptoms]) and 80 controls.

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady state free precession sequence.

ASSESSMENT

Patients were divided into mild (pulmonary artery obstruction index [PAOI] < 30%, N = 57), moderate (30% ≤ PAOI < 50%, N = 27), and severe (50% ≥ PAOI, N = 19) PE subgroups. LA reservoir, conduit, and active pump longitudinal strains (εs, εe, and εa) and strain rates (SRs, SRe, and SRa) and biventricular global strains were measured. Determinants of LA strains were investigated.

STATISTICAL TESTS

ANOVA, t-tests, Mann-Whitney U tests, linear regression. P < 0.05 was considered statistically significant.

RESULTS

For both subacute and chronic PE patients, LA reservoir, conduit, and active pump strains and strain rates were significantly lower than in controls. However, there were no significant differences in LA strains between patients with subacute and chronic PE (P = 0.933, 0.625, and 0.630 for εs, εe, and εa). The severe PE subgroup had significantly higher εa and SRa than the mild and moderate PE subgroups. LA strains were significantly correlated with RV diameter and biventricular strains, and RV diameter (β = -6.836, -4.084, and -1.899 for εs, εe, and εa) was independently associated with LA strains after adjustment for other factors (R2 = 0.627, 0.536, and 0.437 for εs, εe, and εa).

DATA CONCLUSION

LA phasic function evaluated by MRI-FT was significantly impaired in subacute and chronic PE patients, and LA active pump function in the severe PE subgroup was higher than that in the mild and moderate PE subgroups. The independent association between RV diameter and LA strains demonstrates that RV diameter may be an important indicator for monitoring LA dysfunction in PE patients.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 3.

Efficiency and feasibility of semi-automated software for measuring left atrial volume in routine echocardiography in a pediatric population

PURPOSE

The traditional method for measuring left atrial volume (LAV) involves manual tracing. Recently, semi-automated techniques for measuring LAV, based on 2D speckle tracking echocardiography (STE) and 3D echocardiography (3DE), have become commercially available. This study aimed to investigate the efficiency and feasibility of these semi-automated software methods for LAV measurement in pediatric patients.

METHODS

We analyzed 207 pediatric patients with 2D and 3D echocardiographic images of the left atrium. The maximum LAV was measured using three techniques: (1) manual tracing, (2) STE-based semi-automated measurement, and (3) 3DE-based semi-automated measurement. We compared both LAV and the time required for LAV measurement among these three techniques. Intra- and inter-observer reproducibility of the LAV measurements was assessed using the intraclass correlation (ICC).

RESULTS

There was no difference in the LAV between the manual tracing and the STE-based method, but the LAV measured by 3DE-based method was slightly smaller than manual tracing. The measurement time was 32.6 ± 3.5, 53.8 ± 10.8, and 33.8 ± 13.0 s for manual tracing, STE-based, and 3DE-based techniques, respectively. There was no difference the time for LAV measurement between the manual tracing and the 3D-based technique. The agreement and ICC for intra-observer reproducibility was similar across all three techniques, but inter-observer reproducibility was superior with the 3DE-based technique.

CONCLUSIONS

Although the maximum LAV obtained through the 3DE-based techniques was slightly smaller compared with the traditional manual tracing method, the 3DE-based technique is anticipated to be integrated into routine examinations owing to its short measurement time and superior reproducibility.

Longitudinal Assessment of Left Atrial Remodeling in Patients With Chronic Severe Aortic Regurgitation

BACKGROUND

There are significant sex and age differences in left ventricular (LV) remodeling that may lead to disparity in outcomes when used to inform the timing of aortic regurgitation (AR) intervention.

OBJECTIVES

The aim of this study was to examine whether left atrial (LA) parameters might represent better criteria than LV parameters to inform the timing of AR intervention.

METHODS

Using data on patients with moderate to severe or severe AR with serial echocardiography (2010-2016), the longitudinal trends in left atrial volume index (LAVI) and left atrial reservoir strain (LAr) were evaluated by sex and age. The incremental utility of these parameters in predicting adverse events over LV parameters was also determined.

RESULTS

In 525 patients (25.7% women) with 1,687 echocardiograms over a median follow-up period of 2.0 years (Q1-Q3: 1.0-3.6 years), there was significant increase in LAVI (1.0 mL/m2 per year [95% CI: 0.76-1.2 mL/m2 per year]) and decrease in LAr (-1.3% per year [95% CI: -1.6% to -0.92%]), without a significant interaction by sex or age category (P for interaction ≥ 0.17). In addition, both LAVI and LAr were significant predictors of adverse events independent of LV parameters. The optimal discriminatory thresholds were 37 mL/m2 for LAVI and 35% for LAr. These thresholds were similar across categories of sex and age. Within the relatively short-term follow-up, surgery was associated with survival benefit among patients with LAVI ≥37 mL/m2 (HR: 0.33 [95% CI: 0.15-0.72]; P = 0.006) but was not statistically significant among patients with LAVI <37 mL/m2 (HR: 0.46 [95% CI: 0.18-1.17]; P = 0.09). Similarly, surgery was associated with survival for the subgroup with LAr ≤35% but not among those with LAr >35%.

CONCLUSIONS

Unlike LV remodeling, LA remodeling demonstrates a similar rate of progression between categories of sex and age among patients with AR. In addition, LA parameters provide incremental prognostic value over LV parameters.

The assessment of left ventricular diastolic function: guidance and recommendations from the British Society of Echocardiography

Impairment of left ventricular (LV) diastolic function is common amongst those with left heart disease and is associated with significant morbidity. Given that, in simple terms, the ventricle can only eject the volume with which it fills and that approximately one half of hospitalisations for heart failure (HF) are in those with normal/'preserved' left ventricular ejection fraction (HFpEF) (Bianco et al. in JACC Cardiovasc Imaging. 13:258-271, 2020. 10.1016/j.jcmg.2018.12.035), where abnormalities of ventricular filling are the cause of symptoms, it is clear that the assessment of left ventricular diastolic function (LVDF) is crucial for understanding global cardiac function and for identifying the wider effects of disease processes. Invasive methods of measuring LV relaxation and filling pressures are considered the gold-standard for investigating diastolic function. However, the high temporal resolution of trans-thoracic echocardiography (TTE) with widely validated and reproducible measures available at the patient's bedside and without the need for invasive procedures involving ionising radiation have established echocardiography as the primary imaging modality. The comprehensive assessment of LVDF is therefore a fundamental element of the standard TTE (Robinson et al. in Echo Res Pract7:G59-G93, 2020. 10.1530/ERP-20-0026). However, the echocardiographic assessment of diastolic function is complex. In the broadest and most basic terms, ventricular diastole comprises an early filling phase when blood is drawn, by suction, into the ventricle as it rapidly recoils and lengthens following the preceding systolic contraction and shortening. This is followed in late diastole by distension of the compliant LV when atrial contraction actively contributes to ventricular filling. When LVDF is normal, ventricular filling is achieved at low pressure both at rest and during exertion. However, this basic description merely summarises the complex physiology that enables the diastolic process and defines it according to the mechanical method by which the ventricles fill, overlooking the myocardial function, properties of chamber compliance and pressure differentials that determine the capacity for LV filling. Unlike ventricular systolic function where single parameters are utilised to define myocardial performance (LV ejection fraction (LVEF) and Global Longitudinal Strain (GLS)), the assessment of diastolic function relies on the interpretation of multiple myocardial and blood-flow velocity parameters, along with left atrial (LA) size and function, in order to diagnose the presence and degree of impairment. The echocardiographic assessment of diastolic function is therefore multifaceted and complex, requiring an algorithmic approach that incorporates parameters of myocardial relaxation/recoil, chamber compliance and function under variable loading conditions and the intra-cavity pressures under which these processes occur. This guideline outlines a structured approach to the assessment of diastolic function and includes recommendations for the assessment of LV relaxation and filling pressures. Non-routine echocardiographic measures are described alongside guidance for application in specific circumstances. Provocative methods for revealing increased filling pressure on exertion are described and novel and emerging modalities considered. For rapid access to the core recommendations of the diastolic guideline, a quick-reference guide (additional file 1) accompanies the main guideline document. This describes in very brief detail the diastolic investigation in each patient group and includes all algorithms and core reference tables.

Global left ventricular strains and left atrial volumes are not associated in healthy adults - Detailed analysis from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

Introduction

During the heart cycle, left ventricular (LV) contractility is characterized by complex deformation and rotational mechanics, resulting in LV ejection. The present study seeks to expand our knowledge by examining dependence of LV strains representing LV deformation on left atrial (LA) volumes in healthy circumstances. Therefore, the aim of this study was to evaluate the associations between LA volumes and LV strains as assessed simultaneously by three-dimensional speckle-tracking echocardiography (3DSTE) in normal healthy adults.

Methods

The present study consisted of 302 healthy adults, but according to exclusion criteria, 137 subjects were excluded due to inferior image quality. The final population comprised 165 individuals (mean age: 33.1 ± 12.3 years, 75 males) who were voluntarily recruited for screening. Two-dimensional echocardiography extended with 3DSTE was performed in all subjects for detailed LV/LA analysis.

Results

Overall feasibility for simultaneous assessment of LV strains and LA volumes proved to be 55 % with excellent intra- and interobserver correlations. All global LV strains were similar, regardless of the LA volumes examined. All LA volumes and volume-based functional properties respecting the cardiac cycle were similar, regardless the global LV strains examined.

Conclusions

LV strains and LA volumes can be simultaneously assessed by 3DSTE. Global LV strains and LA volumes are not associated in healthy adults.

Echocardiographic findings in apparently healthy Czechoslovakian wolfdogs

INTRODUCTION

To echocardiographically evaluate a large number of apparently healthy Czechoslovakian wolfdogs (CWDs) to identify possible subclinical cardiac abnormalities and to generate reference intervals.

ANIMALS

One-hundred and seventeen apparently healthy client-owned CWDs.

MATERIALS AND METHODS

Standard two-dimensional, M-mode, and Doppler echocardiographic measurements were obtained on non-sedated, manually restrained standing dogs. Animals with no relevant echocardiographic abnormalities were used to generate reference intervals. Echocardiographic variables were compared between males and females and between dogs with and without mitral regurgitation (MR).

RESULTS AND DISCUSSION

Among the 117 CWDs, 103 dogs were used to generate reference intervals. The 14 dogs with abnormalities had more than trivial MR (12 dogs), subaortic stenosis (one dog), and equivocal subaortic stenosis (one dog). The 44 males were heavier than 59 females (P<0.001) and had a larger maximum left atrial dimension (P=0.015), left ventricular internal dimension at end-diastole (P<0.001) and systole (P<0.001), and thicker interventricular septum thickness at end-diastole (P=0.016). A positive linear correlation was identified between bodyweight and aortic root and left atrial diameters and left ventricular dimensions and between age and aortic root and left atrial diameter and peak late transmitral flow velocity. A negative linear correlation was identified between age and peak early transmitral flow velocity and the ratio between peak early and late transmitral flow velocities. No differences in echocardiographic-derived cardiac dimensions were detected between healthy dogs and dogs with more than trivial MR.

CONCLUSIONS

In this population of CWDs, subclinical cardiac abnormalities were uncommon, and they were mainly classified as MR.

Patient-specific multi-physics simulations of fibrotic changes in left atrial tissue mechanics impact on hemodynamics

Stroke is a leading cause of death and disability worldwide. Atrial myopathy, including fibrosis, is associated with an increased risk of ischemic stroke, but the mechanisms underlying this association are poorly understood. Fibrosis modifies myocardial structure, impairing electrical propagation and tissue biomechanics, and creating stagnant flow regions where clots could form. Fibrosis can be mapped non-invasively using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). However, fibrosis maps are not currently incorporated into stroke risk calculations or computational electro-mechano-fluidic models. We present multi-physics simulations of left atrial (LA) myocardial motion and hemodynamics using patient-specific anatomies and fibrotic maps from LGE-MRI. We modify tissue stiffness and active tension generation in fibrotic regions and investigate how these changes affect LA flow for different fibrotic burdens. We find that fibrotic regions and, to a lesser extent, non-fibrotic regions experience reduced myocardial strain, resulting in decreased LA emptying fraction consistent with clinical observations. Both fibrotic tissue stiffening and hypocontractility independently reduce LA function, but together, these two alterations cause more pronounced effects than either one alone. Fibrosis significantly alters flow patterns throughout the atrial chamber, and particularly, the filling and emptying jets of the left atrial appendage (LAA). The effects of fibrosis in LA flow are largely captured by the concomitant changes in LA emptying fraction except inside the LAA, where a multi-factorial behavior is observed. This work illustrates how high-fidelity, multi-physics models can be used to study thrombogenesis mechanisms in a patient-specific manner, shedding light onto the link between atrial fibrosis and ischemic stroke.

Key points

Left atrial (LA) fibrosis is associated with arrhythmogenesis and increased risk of ischemic stroke; its extent and pattern can be quantified on a patient-specific basis using late gadolinium enhancement magnetic resonance imaging.Current stroke risk prediction tools have limited personalization, and their accuracy could be improvedfib by incorporating patient-specific information like fibrotic maps and hemodynamic patterns.We present the first electro-mechano-fluidic multi-physics computational simulations of LA flow, including fibrosis and anatomies from medical imaging.Mechanical changes in fibrotic tissue impair global LA motion, decreasing LA and left atrial appendage (LAA) emptying fractions, especially in subjects with higher fibrosis burdens.Fibrotic-mediated LA motion impairment alters LA and LAA flow near the endocardium and the whole cavity, ultimately leading to more stagnant blood regions in the LAA.

Characterizing the influence of cardiorespiratory fitness on left atrial size and function in the general population

Increased left atrial (LA) size and reduced LA function have been associated with heart failure and atrial fibrillation (AF) in at-risk populations. However, atrial remodeling has also been associated with exercise training and the relationship between fitness, LA size, and function has not been defined across the fitness spectrum. In a cross-sectional study of 559 ostensibly healthy participants, comprising 304 males (mean age, 46 ± 20 yr) and 255 females (mean age, 47 ± 15 yr), we sought to define the relationship between cardiorespiratory fitness (CRF), LA size, and function. We also aimed to interrogate sex differences in atrial factors influencing CRF. Echocardiographic measures included biplane measures of LA volumes indexed to body surface area (LAVi) and atrial deformation using two-dimensional speckle tracking. CRF was measured as peak oxygen consumption (V̇o2peak) during cardiopulmonary exercise testing (CPET). Using multivariable regression, age, sex, weight, and LAVi (P < 0.001 for all) predicted V̇o2peak (P < 0.001, R2 = 0.66 for combined model). After accounting for these variables, heart rate reserve added strength to the model (P < 0.001, R2 = 0.74) but LA strain parameters did not predict V̇o2peak. These findings add important nuance to the perception that LA size is a marker of cardiac pathology. LA size should be considered in the context of fitness, and it is likely that the adverse prognostic associations of increased LA size may be confined to those with LA enlargement and low fitness.NEW & NOTEWORTHY Left atrial (LA) structure better predicts cardiorespiratory fitness (CRF) than LA function. LA function adds little statistical value to predictive models of peak oxygen uptake (V̇o2peak) in healthy individuals, suggesting limited discriminatory for CRF once LA size is factored. In the wider population of ostensibly healthy individuals, the association between increased LA volume and higher CRF provides an important counter to the association between atrial enlargement and heart failure symptoms in those with cardiac pathology.

Modeling the Relationship Between Diastolic Phenotype and Outcomes in Pediatric Hypertrophic Cardiomyopathy

BACKGROUND

Pediatric hypertrophic cardiomyopathy (HCM) is associated with adverse events. The contribution of diastolic dysfunction to adverse events is poorly understood. The aim of this study was to explore the association between diastolic phenotype and outcomes in pediatric patients with HCM.

METHODS

Children <18 years of age with diagnosed with HCM were included. Diastolic function parameters were measured from the first echocardiogram at the time of diagnosis, including Doppler flow velocities, tissue Doppler velocities, and left atrial volume and function. Using principal-component analysis, key features in echocardiographic parameters were identified. The principal components were regressed to freedom from major adverse cardiac events (MACE), defined as implantable cardioverter-defibrillator insertion, myectomy, aborted sudden cardiac death, transplantation, need for mechanical circulatory support, and death.

RESULTS

Variables that estimate left ventricular filling pressures were highly collinear and associated with MACE (hazard ratio, 0.86; 95% CI, 0.75-1.00), though this was no longer significant after controlling for left ventricular thickness and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with outcomes in the covariate-adjusted model (hazard ratio, 0.69; 95% CI, 0.5-0.94). The covariate-adjusted model had an Akaike information criterion of 213, an adjusted R2 value of 0.78, and a concordance index of 0.82 for association with MACE.

CONCLUSION

Echocardiographic parameters of diastolic dysfunction were associated with MACE in this population study, in combination with the severity of left ventricular hypertrophy and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with adverse events. Additional study of diastolic function parameters adjusted for patient size could facilitate the prediction of adverse events in pediatric patients with HCM.

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.

Ablation-induced left atrial mechanical dysfunction recovers in weeks after ablation

BACKGROUND

The immediate impact of catheter ablation on left atrial mechanical function and the timeline for its recovery in patients undergoing ablation for atrial fibrillation (AF) remain uncertain. The mechanical function response to catheter ablation in patients with different AF types is poorly understood.

METHODS

A total of 113 AF patients were included in this retrospective study. Each patient had three magnetic resonance imaging (MRI) studies in sinus rhythm: one pre-ablation, one immediate post-ablation (within 2 days after ablation), and one post-ablation follow-up MRI (≤ 3 months). We used feature tracking in the MRI cine images to determine peak longitudinal atrial strain (PLAS). We evaluated the change in strain from pre-ablation, immediately after ablation to post-ablation follow-up in a short-term study (< 50 days) and a 3-month study (3 months after ablation).

RESULTS

The PLAS exhibited a notable reduction immediately after ablation, compared to both pre-ablation levels and those observed in follow-up studies conducted at short-term (11.1 ± 9.0 days) and 3-month (69.6 ± 39.6 days) intervals. However, there was no difference between follow-up and pre-ablation PLAS. The PLAS returned to 95% pre-ablation level within 10 days. Paroxysmal AF patients had significantly higher pre-ablation PLAS than persistent AF patients in pre-ablation MRIs. Both type AF patients had significantly lower immediate post-ablation PLAS compared with pre-ablation and post-ablation PLAS.

CONCLUSION

The present study suggested a significant drop in PLAS immediately after ablation. Left atrial mechanical function recovered within 10 days after ablation. The drop in PLAS did not show a substantial difference between paroxysmal and persistent AF patients.

Stiff right atrial syndrome? A complex clinical case report utilizing multimodality imaging and invasive hemodynamics

Background

Stiff left atrial syndrome is a well-established cause of heart failure symptoms. A parallel entity involving the right atrium (RA) has not previously been described. We present a case of refractory right heart failure (RHF) 12 years following orthotopic heart transplantation.

Case summary

Patient underwent annuloplasty ring placement for severe tricuspid regurgitation in 2018 and kidney transplantation in 2020. The use of multimodality imaging and a multidisciplinary approach suggested a stiff RA as a potential etiology to refractory symptoms. Redo-heart and kidney transplantation in March 2021 led to the resolution of symptoms without recurrence.

Discussion

We propose stiff right atrial syndrome that may need to be considered in the setting of refractory RHF primarily suggested by significant right atrial enlargement and restrictive physiology.

Left atrial reservoir longitudinal strain and its incremental value to the left ventricular global longitudinal strain in predicting anthracycline-induced cardiotoxicity

BACKGROUND

Left ventricular global longitudinal strain (LVGLS) has been recommended by current guidelines for diagnosing anthracycline-induced cardiotoxicity. However, little is known about the early changes in left atrial (LA) morphology and function in this population. Our study aimed to evaluate the potential usefulness of LA indices and their incremental value to LVGLS with three-dimensional echocardiography (3DE) in the early detection of subclinical cardiotoxicity in patients with lymphoma receiving anthracycline.

METHODS

A total of 80 patients with diffuse large B-cell lymphoma who received six cycles of anthracycline-based treatment were enrolled. Echocardiography was performed at baseline (T0), after four cycles (T1), and after the completion of six cycles of chemotherapy (T2). Left ventricular ejection fraction (LVEF), LVGLS, LA volumes, LA emptying fraction (LAEF), LA active emptying fraction (LAAEF), and LA reservoir longitudinal strain (LASr) were quantified with 3DE. Left atrioventricular global longitudinal strain (LAVGLS) was calculated as the sum of peak LASr and the absolute value of peak LVGLS (LAVGLS = LASr+|LVGLS|). LV cardiotoxicity was defined as a new LVEF reduction by ≥10 percentage points to an LVEF of ≤50%.

RESULTS

Fourteen (17.5%) patients developed LV cardiotoxicity at T2. LA volumes, LAEF, and LAAEF remained stable over time. Impairment of LASr (28.35 ± 5.03 vs. 25.04 ± 4.10, p < .001), LVGLS (-22.77 ± 2.45 vs. -20.44 ± 2.62, p < .001), and LAVGLS (51.12 ± 5.63 vs. 45.61 ± 5.22, p < .001) was observed by the end of the fourth cycle of chemotherapy (T1). Statistically significant declines in LVEF (61.30 ± 4.73 vs. 57.08 ± 5.83, p < .001) were only observed at T2. The relative decrease in LASr (ΔLASr), LVGLS (ΔLVGLS), and LAVGLS (ΔLAVGLS) from T0 to T1 were predictors of LV cardiotoxicity. A ΔLASr of >19.75% (sensitivity, 71.4%; specificity, 87.9%; area under the curve (AUC), .842; p < .001), a ΔLVGLS of >13.19% (sensitivity, 78.6%; specificity, 74.2%; AUC, .763; p < .001), and a ΔLAVGLS of >16.80% (sensitivity, 78.6%; specificity, 93.9%; AUC, .905; p < .001) predicted subsequent LV cardiotoxicity at T2, with the AUC of ΔLAVGLS significantly larger than that of ΔLVGLS (.905 vs. .763, p = .027). Compared to ΔLVGLS, ΔLAVGLS showed improved specificity (93.9% vs. 74.2%, p = .002) and maintained sensitivity in predicting LV cardiotoxicity.

CONCLUSIONS

LASr could predict anthracycline-induced LV cardiotoxicity with excellent diagnostic performance. Incorporating LASr into LVGLS (LAVGLS) led to a significantly improved specificity and maintained sensitivity in predicting LV cardiotoxicity.

Left atrial strain is associated with long-term mortality in acute coronary syndrome patients

To investigate the long-term prognostic value of the left atrial (LA) strain indices - peak atrial longitudinal strain (PALS), peak conduit strain (PCS), and peak atrial contractile strain (PACS) in acute coronary syndrome (ACS) patients in relation to all-cause mortality. This retrospective study included ACS patients treated with percutaneous coronary intervention (PCI) and examined with echocardiography. Exclusion criteria were non-sinus rhythm during echocardiography, missing images, and inadequate image quality for 2D speckle tracking analysis of the LA. The endpoint was all-cause death. Multivariable Cox regression which included relevant clinical and echocardiographic measures was utilized to assess the relationship between LA strain parameters and all-cause mortality. A total of 371 were included. Mean age was 64 years and 76% were male. Median time to echocardiography was 2 days following PCI. During a median follow-up of 5.7 years, 83 (22.4%) patients died. Following multivariable analysis, PALS (HR 1.04, 1.01-1.06, p = 0.002, per 1% decrease) and PCS (HR 1.05, 1.01-1.09, p = 0.006, per 1% decrease) remained significantly associated with all-cause mortality. PALS and PCS showed a linear relationship with the outcome whereas PACS was associated with the outcome in a non-linear fashion such that the risk of death increased when PACS < 18.22%. All LA strain parameters remained associated with worse survival rate when restricting analysis to patients with left atrial volume index < 34 ml/m2. Reduced LA function as assessed by PALS, PCS, and PACS were associated with an increased risk of long-term mortality in patients with ACS.

Implication of sleep apnea for cardiac remodeling in patients with hypertrophic cardiomyopathy

OBJECTIVES

Cardiac remodeling is a life-long process in hypertrophic cardiomyopathy (HCM), and if uncontrolled, would cause substantial morbidity and mortality. Sleep apnea (SA) is a common comorbidity in HCM. This study aimed to investigate the relationship between SA and cardiac remodeling in a large series of patients with HCM.

METHODS

A total of 606 patients with HCM who underwent sleep evaluations at Fuwai Hospital were included. Parameters of cardiac remodeling were evaluated by echocardiographic studies.

RESULTS

SA was present in 363 (59.9%) patients. Left ventricular (LV) end-diastolic diameter (P < 0.001), left atrial (LA) diameter (P = 0.024), ascending aortic diameter (P < 0.001) all increased and maximal end-diastolic wall thickness (P < 0.001) decreased with the severity of SA. After adjustment for sex, age, body mass index, hypertension, hyperlipidemia, diabetes, coronary artery disease and cigarette use, log (apnea-hypopnea index+1) was independently correlated with increasing LV end-diastolic diameter (β = 0.729, P = 0.003) and deceasing maximal end-diastolic wall thickness (β = -0.503, P = 0.009). Log (percentage of total sleep time spent with oxygen saturation<90% + 1) was independently correlated with increasing LV end-diastolic diameter (β = 0.609, P = 0.004) and LA diameter (β = 0.695, P = 0.006). Severity of SA (severe SA with odds ratio, 2.38; 95% CI, 1.20-4.70; P = 0.013), log (apnea-hypopnea index+1) (OR, 1.28; 95% CI, 1.01-1.63; P = 0.045) and log (percentage of total sleep time spent with oxygen saturation<90% + 1) (OR, 1.31; 95% CI, 1.08-1.59; P = 0.006) were also independently associated with LV enlargement.

CONCLUSIONS

Severity of SA is independently associated with cardiac remodeling indicating a trend toward enlarged chamber size and thinned wall. Clinical trials are required to determine whether treatment of SA improves cardiac remodeling and long-term outcomes in patients with HCM.

Fine tuning contractility: atrial sarcomere function in health and disease

The molecular mechanisms of sarcomere proteins underlie the contractile function of the heart. Although our understanding of the sarcomere has grown tremendously, the focus has been on ventricular sarcomere isoforms due to the critical role of the ventricle in health and disease. However, atrial-specific or -enriched myofilament protein isoforms, as well as isoforms that become expressed in disease, provide insight into ways this complex molecular machine is fine-tuned. Here, we explore how atrial-enriched sarcomere protein composition modulates contractile function to fulfill the physiological requirements of atrial function. We review how atrial dysfunction negatively affects the ventricle and the many cardiovascular diseases that have atrial dysfunction as a comorbidity. We also cover the pathophysiology of mutations in atrial-enriched contractile proteins and how they can cause primary atrial myopathies. Finally, we explore what is known about contractile function in various forms of atrial fibrillation. The differences in atrial function in health and disease underscore the importance of better studying atrial contractility, especially as therapeutics currently in development to modulate cardiac contractility may have different effects on atrial sarcomere function.

Comprehensive left atrial flow component analysis reveals abnormal flow patterns in paroxysmal atrial fibrillation

Left atrial (LA) blood flow plays an important role in diseases such as atrial fibrillation (AF) and atrial cardiomyopathy since alterations in the blood flow might lead to thrombus formation and stroke. Using traditional techniques, such as echocardiography, atrial flow velocities can be measured at the pulmonary veins and the mitral valve, but a comprehensive understanding of the three-dimensional atrial flow field is missing. Previously, ventricular flow has been analyzed using flow component analysis, revealing new insights into ventricular flow and function. Thus, the aim of this project was to develop a comprehensive flow component analysis method for the LA and explore its utility in 21 patients with paroxysmal atrial fibrillation compared with a control group of 8 participants. The flow field was derived from time-resolved CT acquired during sinus rhythm using computational fluid dynamics. Flow components were computed from particle tracking. We identified six atrial flow components: conduit, reservoir, delayed ejection, retained inflow, residual volume, and pulmonary vein backflow. It was shown that conduit flow, defined as blood entering and leaving the LA within the same diastolic phase, exists in most subjects. Although the volume of conduit and reservoir is similar in patients with paroxysmal AF in sinus rhythm and controls, the volume of the other components is increased in paroxysmal AF. Comprehensive quantification of LA flow using flow component analysis makes atrial blood flow quantifiable, thus facilitating investigation of mechanisms underlying atrial dysfunction and can increase understanding of atrial blood flow in disease progression and stroke risk.NEW & NOTEWORTHY We developed a new comprehensive approach to atrial blood component analysis that includes both conduit flow and residual volume and compared the flow components of atrial fibrillation (AF) patients in sinus rhythm with controls. Conduit and reservoir flow were similar between the groups, whereas components with longer residence time in the left atrium were increased in the AF group. This could add to the pathophysiological understanding of atrial diseases and possibly clinical management.

Left ventricular to left arial volume ratio in the assessment of filling pressure in patients with dyspnoea and preserved ejection fraction

Introduction

Assessing filling pressure (FP) remains a clinical challenge despite advancements in non-invasive imaging techniques. This study investigates the utility of echocardiographic left ventricular (LV) to left atrial (LA) volume ratio in estimating the resting FP in patients with dyspnoea and preserved ejection fraction (EF).

Methods

This study is a prospective, single-centre analysis of 53 consecutive patients with dyspnoea (New York Heart Association grade 2 or 3) and LVEF of ≥50% (mean age 71 ± 10 years) who underwent cardiac catheterisation, including direct measurement of LA pressure at rest using retrograde technique. Echocardiographic data were obtained 1.5 ± 1.0 h after cardiac catheterisation. The patients were divided into two groups: Group 1 consisted of individuals with elevated FP, indicated by a mean LA pressure or mean pulmonary capillary wedge pressure of >12 mmHg, and Group 2 comprised of patients with normal FP. The LV and LA volumes were measured at three specific points: the minimum volume (LVES, LAmin), the volume during diastasis (LVdias, LAdias), and the maximum volume (LVED, LAmax). The corresponding LV/LA volume ratios were analysed: end-systole (LVES/LAmax), diastasis (LVdias/LAdias), and end-diastole (LVED/LAmin).

Results

The patients in Group 1 exhibited lower LV/LA volume ratios compared with those in Group 2 (LVES/LAmax 0.44 ± 0.12 vs. 0.60 ± 0.23, P = 0.0032; LVdias/LAdias 1.13 ± 0.30 vs. 1.56 ± 0.49, P = 0.0007; LVED/LAmin 2.71 ± 1.57 vs. 4.44 ± 1.70, P = 0.0004). The LV/LA volume ratios correlated inversely with an increased FP (LVES/LAmax, r = -0.40, P = 0.0033; LVdias/LAdias, r = -0.45, P = 0.0007; LVED/LAmin, r = -0.55, P < 0.0001). Among all the measurements, the LVdias/LAdias ratio demonstrated the highest discriminatory power to distinguish patients with elevated FP from normal FP, with a cut-off value of ≤1.24 [area under the curve (AUC) = 0.822] for the entire group, encompassing both sinus rhythm and atrial fibrillation. For patients in sinus rhythm specifically, the cut-off value was ≤1.28 (AUC = 0.799), with P < 0.0001 for both. The LVdias/LAdias index demonstrated non-inferiority to the E/e' ratio [ΔAUC = 0.159, confidence interval (CI) = -0.020-0.338; P = 0.0809], while surpassing the indices of LA reservoir function (ΔAUC = 0.249, CI = 0.044-0.454; P = 0.0176), LA reservoir strain (ΔAUC = 0.333, CI = 0.149-0.517; P = 0.0004), and LAmax index (ΔAUC = 0.224, CI = 0.043-0.406; P = 0.0152) in diagnosing patients with elevated FP.

Conclusion

The study presents a straightforward and reproducible method for non-invasive estimation of FP using routine TTE in patients with dyspnoea and preserved EF. The LVdias/LAdias index emerges as a promising indicator for identifying elevated FP, demonstrating comparable or even superior performance to established parameters.

Investigating the importance of left atrial compliance on fluid dynamics in a novel mock circulatory loop

The left atrium (LA) hemodynamic indices hold prognostic value in various cardiac diseases and disorders. To understand the mechanisms of these conditions and to assess the performance of cardiac devices and interventions, in vitro models can be used to replicate the complex physiological interplay between the pulmonary veins, LA, and left ventricle. In this study, a comprehensive and adaptable in vitro model was created. The model includes a flexible LA made from silicone and allows distinct control over the systolic and diastolic functions of both the LA and left ventricle. The LA was mechanically matched with porcine LAs through expansion tests. Fluid dynamic measures were validated against the literature and pulmonary venous flows recorded on five healthy individuals using magnetic resonance flow imaging. Furthermore, the fluid dynamic measures were also used to construct LA pressure-volume loops. The in vitro pressure and flow recordings expressed a high resemblance to physiological waveforms. By decreasing the compliance of the LA, the model behaved realistically, elevating the a- and v-wave peaks of the LA pressure from 12 to 19 mmHg and 22 to 26 mmHg, respectively, while reducing the S/D ratio of the pulmonary venous flowrate from 1.5 to 0.3. This model provides a realistic platform and framework for developing and evaluating left heart procedures and interventions.

Effect of physiological and pharmacological stress on heart rate, blood pressure, and echocardiographic measurements in healthy Warmblood horses

BACKGROUND

Echocardiographic measurements are important prognostic indicators but might be influenced by heart rate and blood pressure. This is particularly important when comparing repeated examinations.

HYPOTHESIS

To determine the effect of physiological stress at mildly increased heart rates and pharmacological challenge using IV administration of N-butylscopolammonium bromide and metamizol sodium on heart rate, blood pressure, and echocardiographic measurements.

ANIMALS

Twenty healthy Warmblood horses.

METHODS

Randomized crossover study. Horses were examined echocardiographically by 2-dimensional, M-mode, pulsed wave (PW) Doppler, and PW tissue Doppler imaging with simultaneous ECG recording and noninvasive blood pressure measurements during rest, physiological stress, and pharmacological challenge. Cardiac dimensions and functions were measured by a blinded observer. Data were analyzed using repeated-measures analysis of variance.

RESULTS

Mean heart rate and arterial blood pressure were significantly higher during physiological stress (46 ± 2 bpm, 93 ± 16 mm Hg) and pharmacological challenge (62 ± 13 bpm, 107 ± 17 mm Hg) compared with rest (34 ± 3 bpm, 86 ± 12 mm Hg; P < .05). Compared with rest, physiological stress resulted in increased left atrial fractional area change (34.3 ± 7.5 vs 27.3 ± 5.1%; P = .01) and left ventricular late diastolic radial wall motion velocity (13 ± 3 vs 10 ± 2 cm/s; P = .01) but had no significant effect on most other echocardiographic variables. Compared with rest, pharmacological challenge led to significantly decreased left atrial and diastolic ventricular dimensions (left ventricular internal diameter: 10.3 ± 0.9 vs 10.7 ± 0.8 cm; P = .01), increased aortic and pulmonary diameters, and ventricular wall thickness.

CONCLUSIONS AND CLINICAL IMPORTANCE

Physiological stress at mildly increased heart rates significantly enhanced atrial pump function. Larger heart rate and blood pressure increases during pharmacological challenge resulted in altered cardiac dimensions. This should be taken into account when evaluating echocardiographic measurements at increased heart rates.

Associating the Severity of Emphysema with Coronary Flow Reserve and Left Atrial Conduit Function for the Emphysema Patients with Known or Suspected Coronary Artery Disease

PURPOSE

Pulmonary emphysema may associate with ischemic heart disease through systemic microvascular abnormality as a common pathway. Stress cardiovascular MR (CMR) allows for the assessment of global coronary flow reserve (CFR). The purpose of this study was to evaluate the association between the emphysema severity and the multiple MRI parameters in the emphysema patients with known or suspected coronary artery disease (CAD).

METHODS

A total of 210 patients with known or suspected CAD who underwent both 3.0T CMR including cine CMR, stress and rest perfusion CMR, stress and rest phase-contrast (PC) cine CMR of coronary sinus, and late gadolinium enhancement (LGE) CMR, and lung CT within 6 months were studied. Global CFR, volumes and functions of both ventricles and atria, and presence or absence of myocardial ischemia and infarction were evaluated. Emphysema severity was visually determined on lung CT by Goddard method.

RESULT

Seventy nine (71.0 ± 7.9 years, 75 male) of 210 patients with known or suspected CAD had emphysema on lung CT. Goddard score was significantly correlated with CFR (r = -0.246, P = 0.029), left ventricular end-diastolic volume index (LV EDVI) (r = -0.230, P = 0.041), right ventricular systolic volume index (RV SVI) (r = -0.280, P = 0.012), left atrial (LA) total emptying volume index (r = -0.269, P = 0.017), LA passive emptying volume index (r = -0.309, P = 0.006), LA systolic strain (Es) (r = -0.244, P = 0.030), and LA conduit strain (Ee) (r = -0.285, P = 0.011) in the patients with emphysema. Multiple linear regression analysis revealed LA conduit function was independently associated with emphysema severity as determined by Goddard method (beta = -0.361, P = 0.006).

CONCLUSION

LA conduit function independently associates with emphysema severity in the emphysema patients with known or suspected CAD after adjusting age, sex, smoking, and the CMR indexes including CFR. These findings suggest that impairment of LA function predominantly occurs prior to the reduction of the CFR in the emphysema patients with known or suspected CAD.

Assessment of left atrial myocardial deformation using two-dimensional speckle-tracking echocardiography in cats with cardiogenic and non-cardiogenic arterial thromboembolism

Arterial thromboembolism (ATE) in cats usually relates to cardiogenic causes that can be diagnosed by conventional echocardiography. Two-dimensional speckle-tracking echocardiography (2D-STE) is a new ultrasound modality with higher sensitivity. Our objective was to investigate left atrial myocardial deformation in cats with both cardiogenic and non-cardiogenic ATE and normal cats using 2D-STE. Twenty-three normal cats and 21 cats with ATE cats were recruited and performed conventional echocardiography and 2D-STE. From the results, left atrial (LA) strain and strain rate from 2D-STE were significantly decreased in cats with cardiogenic ATE (P < 0.001), but there was no significant difference in non-cardiogenic ATE compared with normal cats. From the correlation test, the use of left atrial strain during the reservoir phase (LASr) could represent the overall LA deformation. The intra- and inter-observer coefficient of variation of LASr was less than 15%. The logistic regression revealed that the LASr value of less than 11% was a significant factor for the occurrence of ATE (odd ratio = 189.0, P < 0.001). In conclusion, LASr derived by 2D-STE is a repeatable and non-invasive technique to assess LA myocardial deformation in cats with ATE. By 2D-STE, impaired LA function was detected in cats with cardiogenic ATE. LASr < 11% may use as a predictor of the risk of ATE occurrence in cats.

Changes of left atrial morphology and function evaluated with four-dimensional automated left atrial quantification echocardiography in patients with coronary slow flow phenomenon and preserved left ventricular ejection fraction

BACKGROUND

Coronary slow flow phenomenon (CSFP) can cause left ventricular diastolic dysfunction (LVDD). In multiple studies, the left atrial (LA) strain has been reported to be an excellent parameter for assessing LVDD. The 4-dimensional automated LA quantification (4D Auto LAQ) dedicated to the LA was recently available. Our study aimed to evaluate subclinical changes in LA morphology and function with 4D Auto LAQ in patients with CSFP and preserved left ventricular ejection fraction (LVEF).

METHODS

Forty-eight patients with CSFP confirmed with coronary angiography and 46 age and gender-matched controls with normal coronary flow were enrolled. The thrombolysis in myocardial infarction frame count (TFC) method was used to record coronary blood flow velocities for each major coronary artery. LA volume, LA longitudinal and circumferential strains during each of the three LA phases (reservoir, conduit, and contraction), LA total emptying fraction (LATEF), LA active emptying fraction (LAAEF), and LA passive emptying fraction (LAPEF) were quantified with 4D Auto LAQ analysis.

RESULTS

Compared with controls, LA longitudinal reservoir strain (LASr), LA longitudinal strain during the conduit phase (LAScd), LA contraction strain (LASct), LA conduit circumferential strain (LAScd-c), LATEF, LAPEF decreased significantly in individuals with CSFP. Of the 4D- LAQ parameters, only LASr [odds ratio (OR): 0.773, P < 0.001] and LATEF [OR: 0.762, P < 0.001] were associated with CSFP in multivariate analysis. A LASr ≤23.00% can differentiate CSFP from controls [sensitivity, 66.7%; specificity, 93.5%; area under the curve (AUC), 0.823; P < 0.001]. A LASr of ≤19.00% could predict the elevation of LV filling pressure in the CSFP cohort [sensitivity, 76.9%; specificity, 74.3%; area under the curve (AUC), 0.792; P < 0.001]. LASr was the only index to demonstrate significant changes compared to controls in single-vessel CSFP. Compared to the right coronary artery (RCA) and left circumflex (LCX), TFC of the left anterior descending (LAD) artery was the only independent variable of LASr (Standardized Coefficients: -0.386, P = 0.037).

CONCLUSIONS

Impairment of LA reservoir function reflected by changes in LASr and LATEF can be seen in patients with CSFP. LASr could predict the elevation of LV filling pressure in CSFP individuals. LASr is more sensitive than LATEF in detecting LA reservoir dysfunction in single-vessel CSFP. CSFP in LAD exerts a more prominent influence on LASr than RCA or LCX.

The impact of image and performance enhancing drugs on atrial structure and function in resistance trained individuals

BACKGROUND

Image and performance enhancing drugs (IPEDs) are commonly used in resistance trained (RT) individuals and negatively impact left ventricular (LV) structure and function. Few studies have investigated the impact of IPEDs on atrial structure and function with no previous studies investigating bi-atrial strain. Additionally, the impact of current use vs. past use of IPEDs is unclear.

METHODS

Utilising a cross-sectional design, male (n = 81) and female (n = 15) RT individuals were grouped based on IPED user status: current (n = 57), past (n = 19) and non-users (n = 20). Participants completed IPED questionnaires, anthropometrical measurements, electrocardiography, and transthoracic echocardiography with strain imaging. Structural cardiac data was allometrically scaled to body surface area (BSA) according to laws of geometric similarity.

RESULTS

Body mass and BSA were greater in current users than past and non-users of IPEDs (p < 0.01). Absolute left atrial (LA) volume (60 ± 17 vs 46 ± 12, p = 0.001) and right atrial (RA) area (19 ± 4 vs 15 ± 3, p < 0.001) were greater in current users than non-users but this difference was lost following scaling (p > 0.05). Left atrial reservoir (p = 0.008, p < 0.001) and conduit (p < 0.001, p < 0.001) strain were lower in current users than past and non-users (conduit: current = 22 ± 6, past = 29 ± 9 and non-users = 31 ± 7 and reservoir: current = 33 ± 8, past = 39 ± 8, non-users = 42 ± 8). Right atrial reservoir (p = 0.015) and conduit (p = 0.007) strain were lower in current than non-users (conduit: current = 25 ± 8, non-users = 33 ± 10 and reservoir: current = 36 ± 10, non-users = 44 ± 13). Current users showed reduced LV diastolic function (A wave: p = 0.022, p = 0.049 and E/A ratio: p = 0.039, p < 0.001) and higher LA stiffness (p = 0.001, p < 0.001) than past and non-users (A wave: current = 0.54 ± 0.1, past = 0.46 ± 0.1, non-users = 0.47 ± 0.09 and E/A ratio: current = 1.5 ± 0.5, past = 1.8 ± 0.4, non-users = 1.9 ± 0.4, LA stiffness: current = 0.21 ± 0.7, past = 0.15 ± 0.04, non-users = 0.15 ± 0.07).

CONCLUSION

Resistance trained individuals using IPEDs have bi-atrial enlargement that normalises with allometric scaling, suggesting that increased size is, in part, associated with increased body size. The lower LA and RA reservoir and conduit strain and greater absolute bi-atrial structural parameters in current than non-users of IPEDs suggests pathological adaptation with IPED use, although the similarity in these parameters between past and non-users suggests reversibility of pathological changes with withdrawal.

Mueller maneuver attenuates left atrial phasic volumes and myocardial strain in healthy younger adults

The left atrium (LA) is a key, but incompletely understood, modulator of left ventricular (LV) filling. Inspiratory negative intrathoracic pressure swings alter cardiac loading conditions, which may impact LA function. We studied acute effects of static inspiratory efforts on LA chamber function, LA myocardial strain, and LV diastolic filling. We included healthy adults (10 males/9 females, 24 ± 4 yr) and used Mueller maneuvers to reduce intrathoracic pressure to -30 cmH2O for 15 s. Over six repeated trials, we used echocardiography to acquire LA- and LV-focused two-dimensional (2-D) images, and mitral Doppler inflow and annular tissue velocity spectra. Images were analyzed for LA and LV chamber volumes, tissue relaxation velocities, transmitral filling velocities, and speckle tracking-derived LA longitudinal strain. Repeated measures were made at baseline, early Mueller, late Mueller, then early release, and late release. In the late Mueller compared with baseline, LV stroke volume decreased by -10 ± 4 mL (P < 0.05) and then returned to baseline upon release; this occurred with a -11 ± 9 mL (P < 0.05) end-diastolic volume reduction. Early diastolic LV filling was attenuated, reflected by decreased tissue relaxation velocity (-2 ± 2 cm/s, P < 0.05), E-wave filling velocity (-13 ± 14 cm/s, P < 0.05), and LA passive emptying volume (-5 ± 5 mL, P < 0.05), each returning to baseline with release. LA maximal volume decreased (-5 ± 5 mL, P < 0.05) during the Mueller maneuver, but increased relative to baseline following release (+4 ± 5 mL, P < 0.05), whereas LA peak positive longitudinal strain decreased (-6 ± 6%, P < 0.05) and then returned to baseline. Attenuated LA and in turn, LV filling may contribute to acute stroke volume reductions experienced during forceful inspiratory efforts.NEW & NOTEWORTHY In healthy younger adults, the Mueller maneuver transiently reduces left atrial filling and passive emptying during the reservoir and conduit phases, respectively. Corresponding reductions are seen in left atrial reservoir and conduit phase longitudinal myocardial strain and strain rate. However, left atrial pump phase active function and mechanics are largely preserved compared with baseline. Rapid changes in LA chamber volumes and myocardial strain with recurrent forceful inspiratory efforts and relaxation may reflect acute LA stress.

Early Remodeling of the Left Atrium Following Catheter Ablation of Atrial Fibrillation: Insights From DECAAFII

BACKGROUND

Left atrial (LA) enlargement is prevalent among atrial fibrillation (AF) patients and constitutes an important marker of atrial myopathy. Several studies have described reduction in LA volume post-catheter ablation (CA) of AF, however, none have investigated differences related to additional ablation outside the pulmonary veins (PVs).

OBJECTIVES

The authors sought to study early LA remodeling following CA of persistent AF and the impact of additional, fibrosis-guided extra-PV ablation.

METHODS

In this DECAAF II (Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) trial subanalysis, patients with persistent AF were randomized to receive pulmonary vein isolation (PVI) only or PVI + fibrosis-guided ablation. Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) was performed before and 3 months after CA. Patients were followed up with single-lead electrocardiogram devices for 12 to18 months. AF burden was calculated as days with AF divided by days monitored.

RESULTS

This analysis included 733 patients. The mean LA volume index (LAVI) before ablation was 62.0 mm3/m2 and after ablation was 51.3 mm3/m2, with a mean reduction of 10.7 mm3/m2 (P < 0.001). Patients in the fibrosis-guided ablation arm had more volume reduction than did those in the PVI-only group (12.1 mm3/m2 vs 9.3 mm3/m2; P = 0.02). LAVI reduction was greater in patients with heart failure (15.7 vs 8.9; P = 0.001) and was associated with improved left ventricular ejection fraction (LVEF) (r = 0.23; P < 0.001), reduced AF burden (r = -0.173; P < 0.001), improved LVEF, and improved quality of life (r = 0.146; P < 0.001).

CONCLUSIONS

We confirmed the presence of LA remodeling within 3 months after ablation for persistent AF. Importantly, we saw more LA volume reductions in patients in the PVI + fibrosis-guided ablation arm in comparison with PVI only, and in patients with LV dysfunction. LA volume reduction in response to CA is associated with decreased arrhythmia recurrence, reduced AF burden, and improved LVEF and quality of life.

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.

Use of speckle tracking echocardiography in evaluating cardiac dysfunction in patients with acromegaly: an update

In recent years, cardiovascular disease has garnered increasing attention as the second leading cause of death in individuals with acromegaly, following malignancy. Identifying cardiac dysfunction early in acromegaly patients for timely intervention has become a focal point of clinical research. Speckle tracking echocardiography, a well-established ultrasound technique, surpasses conventional Doppler ultrasound in its sensitivity to assess both local and global cardiac mechanics. It can accurately detect subclinical and clinical myocardial dysfunction, including myocardial ischemia, ventricular hypertrophy, and valvular changes. Over the past five years, the use of speckle tracking echocardiography in acromegaly patients has emerged as a novel approach. Throughout the cardiac cycle, speckle tracking echocardiography offers a sensitive evaluation of the global and regional myocardial condition by quantifying the motion of myocardial fibres in distinct segments. It achieves this independently of variations in ultrasound angle and distance, effectively simulating the deformation of individual ventricles across different spatial planes. This approach provides a more accurate description of changes in cardiac strain parameters. Importantly, even in the subclinical stage when ejection fraction remains normal, the strain parameters assessed by speckle tracking echocardiography hold a good predictive value for the risk of cardiovascular death and hospitalization in acromegaly patients with concomitant cardiovascular disease. This information aids in determining the optimal timing for interventional therapy, offering important insights for cardiac risk stratification and prognosis. In the present study, we comprehensively reviewed the research progress of speckle tracking echocardiography in evaluating of cardiac dysfunction in acromegaly patients, to pave the way for early diagnosis of acromegaly cardiomyopathy.

Decreased diastolic hydraulic forces incrementally associate with survival beyond conventional measures of diastolic dysfunction

Decreased hydraulic forces during diastole contribute to reduced left ventricular (LV) filling and heart failure with preserved ejection fraction. However, their association with diastolic function and patient outcomes are unknown. The aim of this retrospective, cross-sectional study was to determine the mechanistic association between diastolic hydraulic forces, estimated by echocardiography as the atrioventricular area difference (AVAD), and both diastolic function and survival. Patients (n = 5176, median [interquartile range] 5.5 [5.0-6.1] years follow-up, 1213 events) were selected from the National Echo Database Australia (NEDA) based on the presence of relevant transthoracic echocardiographic measures, LV ejection fraction (LVEF) ≥ 50%, heart rate 50-100 beats/minute, the absence of moderate or severe valvular disease, and no prior prosthetic valve surgery. NEDA contains echocardiographic and linked national death index mortality outcome data from 1985 to 2019. AVAD was calculated as the cross-sectional area difference between the LV and left atrium. LV diastolic dysfunction was graded according to 2016 guidelines. AVAD was weakly associated with E/e', left atrial volume index, and LVEF (multivariable global R2 = 0.15, p < 0.001), and not associated with e' and peak tricuspid regurgitation velocity. Decreased AVAD was independently associated with poorer survival, and demonstrated improved model discrimination after adjustment for diastolic function grading (C-statistic [95% confidence interval] 0.644 [0.629-0.660] vs 0.606 [0.592-0.621], p < 0.001) and E/e' (0.649 [0.635-0.664] vs 0.634 [0.618-0.649], p < 0.001), respectively. Therefore, decreased hydraulic forces, estimated by AVAD, are weakly associated with diastolic dysfunction and demonstrate an incremental prognostic association with survival beyond conventional measures used to grade diastolic dysfunction.

Progressive alterations of left atrial and ventricular volume and strain across chronic kidney disease stages: a speckle tracking echocardiography study

Background

It has been a scarcity of evidence regarding differences in left ventricular (LV) and left atrial (LA) size and strain changes across stages of chronic kidney disease (CKD) and which echocardiographic parameters could be utilized to predict the decline of glomerular filtration rate (GFR).

Objectives

This study aimed to evaluate the alterations of LV and LA strain across the reduction of renal function and potential echocardiographic parameters which could be correlated with the GFR decline among patients with CKD.

Method

A cross-sectional study was conducted on 169 CKD patients at Bach Mai General Hospital, Hanoi, Vietnam from April to November 2022. Demographic, clinical and laboratory characteristics of patients were collected. Transthoracic echocardiography was performed to measure LV and LA size and strains. Jonckheere-Terpstra test was used to measure the tendency of change. Multivariate linear regression models were performed to find associations between different echocardiographic parameters and renal function reduction.

Results

The number of patients with CKD stages 1, 2, 3, 4, and 5 was 21 (12.4%), 28 (16.6%), 27 (16.0%), 22 (13.0%) and 71 (42.0%), respectively. CKD severity was positively associated with LV diastolic and systolic diameters, LV mass, E/e' ratio, and maximal tricuspid regurgitation velocity (TR max), and negatively correlated with the LV global longitudinal strain. Higher severity of CKD stage was associated with higher LA diameter, LA strain, and volume in four and two-chamber views, and lower LA reservoir and conduit function. Left ventricular mass (β = 0.068), ejection fraction (β = 0.112) and left atrial reservoir (β = -0.077) were associated with reduced GFR.

Conclusion

Left ventricular mass, ejection fraction, and atrial longitudinal strain by STE should be done at the earlier stages of CKD patients for better follow-up of GFR decline.

Prediction of spontaneous echocardiographic contrast within the left atrial appendage in cardiac computed tomography of patients with atrial fibrillation

This study aimed to assess the predictors of spontaneous echocardiographic contrast (SEC) using left atrial appendage (LAA) findings in cardiac computed tomography (CT) of patients with atrial fibrillation (AF). We retrospectively analyzed cardiac CT findings of the LAA, including morphology, volume, and filling defects, of 641 patients who underwent transesophageal echocardiography (TEE) prior to pulmonary vein isolation (PVI) from January 6, 2013 through December 16, 2019 at our institution. We investigated potential associated factors that might be predictors of SEC using cardiac CT findings and computed a receiver operator characteristic, choosing a threshold value at which the likelihood of SEC could be predicted based on the LAA volume indexed for body size. SEC correlated significantly with indexed LAA volume (P < 0.001; odds ratio [OR], 1.31; 95% confidence interval [CI], 1.17-1.48) of 7.75 cm3/m2 or greater (sensitivity, 76.0%; specificity, 57.7%), LAA early filling defect (P = 0.005; OR, 2.72; 95% CI, 1.35-5.48), a history of persistent AF (P < 0.001; OR, 3.81; 95% CI, 1.86-7.80), and LAA flow velocity (P < 0.001; OR, 0.97; 95% CI, 0.96-0.99). Findings of LAA in cardiac CT can allow for the noninvasive estimation of SEC to determine the need for additional TEE investigation and the need to obtain additional information for risk stratification and management of thromboembolic events in patients with AF.

Hypertensive Heart Disease: A Narrative Review Series-Part 2: Macrostructural and Functional Abnormalities

Hypertensive heart disease (HHD) remains a major global public health concern despite the implementation of new approaches for the management of hypertensive patients. The pathological changes occurring during HHD are complex and involve the development of structural and functional cardiac abnormalities. HHD describes a broad spectrum ranging from uncontrolled hypertension and asymptomatic left ventricular hypertrophy (LVH), either a concentric or an eccentric pattern, to the final development of clinical heart failure. Pressure-overload-induced LVH is recognised as the most important predictor of heart failure and sudden death and is associated with an increased risk of cardiac arrhythmias. Cardiac arrhythmias are considered to be one of the most important comorbidities affecting hypertensive patients. This is the second part of a three-part set of review articles. Here, we focus on the macrostructural and functional abnormalities associated with chronic high pressure, their involvement in HHD pathophysiology, and their role in the progression and prognosis of HHD.

Peak left atrial longitudinal strain is associated with all-cause mortality in patients with ventricular functional mitral regurgitation

PURPOSE

Chronic mitral regurgitation promotes left atrial (LA) remodeling. However, the significance of LA dysfunction in the setting of ventricular functional mitral regurgitation (FMR) has not been fully investigated. Our aim was to assess the prognostic impact of peak atrial longitudinal strain (PALS), a surrogate of LA function, in patients with FMR and reduced left ventricular ejection fraction (LVEF).

METHODS

Patients with at least mild ventricular FMR and LVEF < 50% under optimized medical therapy who underwent transthoracic echocardiography at a single center were retrospectively identified in the laboratory database. PALS was assessed by 2D speckle tracking in the apical 4-chamber view and the study population was divided in two groups according to the best cut-off value of PALS, using receiver operating characteristics (ROC) curve analysis. The primary endpoint-point was all-cause mortality.

RESULTS

A total of 307 patients (median age 70 years, 77% male) were included. Median LVEF was 35% (IQR: 27 - 40%) and median effective regurgitant orifice area (EROA) was 15mm² (IQR: 9 - 22mm²). According to current European guidelines, 32 patients had severe FMR (10%). During a median follow-up of 3.5 years (IQR 1.4 - 6.6), 148 patients died. The unadjusted mortality incidence per 100 persons-years increased with progressively lower values of PALS. On multivariable analysis, PALS remained independently associated with all-cause mortality (adjusted hazard ratio 1.052 per % decrease; 95% CI: 1.010 - 1.095; P = 0.016), even after adjustment for several (n = 14) clinical and echocardiographic confounders.

CONCLUSION

PALS is independently associated with all-cause mortality in patients with reduced LVEF and ventricular FMR.

Association of lipid composition and unsaturated fatty acids of VLDL with atrial remodeling in metabolic syndrome

Subjects with metabolic syndrome (MetS) commonly have atrial remodeling, which indicates a risk for atrial fibrillation. This study determined MetS-related changes in lipid components in very-low-density lipoprotein (VLDL), which has been shown to cause atrial remodeling, the effect of statins on these changes, and the correlation between atrial remodeling and VLDL lipid compositions. Blood samples were collected from 12 non-MetS and 27 sex- and age-matched MetS subjects. Fourteen patients with MetS (MetS-off statin) discontinued statin therapy 14 days before the study, while the remaining 13 remained on it (MetS-on statin). The VLDLs were isolated and processed for mass-based lipid profiling. Lipidomic analyses were performed and associated with atrial remodeling markers measured using standard echocardiography and electrocardiography. Compared with the VLDL components of the non-MetS group, glucosyl/galactosyl ceramide, lyso-phosphatidylcholine, lyso-phosphatidylethanolamine, and triglycerides were enriched in the MetS-off statin group. Statin therapy attenuated all abnormally abundant lipid classes in MetS, except for triglycerides. In addition, lyso-phosphatidylcholine, lyso-phosphatidylethanolamine, and triglycerides were significantly correlated with atrial dilatation, and the latter two were also correlated with the PR interval. Enrichment of double bonds, which indicate unsaturated fatty acids, was also significantly correlated with atrial remodeling and P-wave duration. This study suggests that the pathological lipid payload of MetS-VLDL may contribute to atrial remodeling in patients.

Cardiac Resynchronization Therapy and Left Atrial Remodeling: A Novel Insight?

Cardiac resynchronization therapy (CRT) restores ventricular dyssynchrony, improving left ventricle (LV) systolic function, symptoms, and outcome in patients with heart failure, systolic dysfunction, and prolonged QRS interval. The left atrium (LA) plays tremendous roles in maintaining cardiac function, being often inflicted in various cardiovascular diseases. LA remodeling implies structural-dilation, functional-altered phasic functions, and strain and electrical-atrial fibrillation remodeling. Until now, several important studies have approached the relationship between LA and CRT. LA volumes can predict responsiveness to CRT, being also associated with improved outcome in these patients. LA function and strain parameters have been shown to improve after CRT, especially in those who were positive responders to it. Further studies still need to be conducted to comprehensively characterize the impact of CRT on LA phasic function and strain, and, also, in conjunction with its impact on functional mitral regurgitation and LV diastolic dysfunction. The aim of this review was to provide an overview of current available data regarding the relation between CRT and LA remodeling.

Echocardiographic Measures of Left Atrial Structure and Function and the Association with Atrial Fibrillation following Acute Coronary Syndrome

INTRODUCTION

Acute coronary syndrome (ACS) is associated with an increased risk of developing atrial fibrillation (AF). This arrhythmia is associated with adverse outcomes, making it important to identify high-risk patients. The aim was to evaluate the prognostic value of measures of left atrial (LA) structure and function in AF prediction following ACS.

METHODS

Three hundred and eighty-one patients who had a percutaneous coronary intervention for ACS were included in the study. Our endpoint was new-onset AF.

RESULTS

With a median follow-up time of 5.4 [3.9-6.8] years, 56 patients (14.7%) developed AF. Patients developing AF had significantly (p ≤ 0.05) increased maximal and minimal LA volumes (LAVmax and LAVmin, respectively). LAVmax and LAVmin remained significantly increased in AF patients when indexing to either body surface area (LAVmax/BSA and LAVmin/BSA, respectively), left ventricle length in end diastole (LAVmax/LVLd and LAVmin/LVLd, respectively), or late mitral annular diastolic velocity (LAVmax/a' and LAVmin/a', respectively), while LA expansion index (LAEi), LA emptying fraction (LAEF), and peak LA longitudinal strain (PALS) were decreased. In univariable Cox regressions, all LA measures were found to be predictors of AF. After multivariable adjustment for clinical and echocardiographic parameters, all measures reflecting atrial function (LAVmin, LAVmin/BSA, LAVmin/LVLd, LAVmin/a', LAVmax/a', LAEF, LAEi, and PALS) (p ≤ 0.05) but no structural measures (LAVmax, LAVmax/BSA, and LAVmax/LVLd) remained significant independent predictors of AF.

CONCLUSION

Echocardiographic measures of LA function are independent predictors of AF following ACS. Evaluation of LA function might improve the prognostic workup, aid in risk stratification for AF, and improve selection for further examinations.

Echocardiographic Correlates of Left Atrial Function Index Among Hypertensive Heart Failure Patients: A Cross-Sectional Study

Background Heart failure contributes to the global burden of cardiovascular diseases, with hypertensive heart failure affecting individuals in their productive age group and leading to high economic losses and disability-adjusted life years. The left atrium, on the other hand, contributes significantly to left ventricular filling in heart failure patients, and the left atrial function index is an excellent tool for assessing left atrial function among heart failure patients. The study aimed to evaluate some parameters of systolic and diastolic function as correlates and potential predictors of the left atrial function index among hypertensive heart failure cohorts. Materials and methods The study was conducted at Delta State University Teaching Hospital, Oghara. Eighty (80) patients with hypertensive heart failure who met the inclusion criteria were enrolled in the cardiology outpatient clinics. The left atrial function index was calculated using the following formula: LAFI = (LAEF x LVOT-VTI)/LAESVI. (LAFI = left atrial function index; LAEF = left atrial emptying fraction; LAESVI = left atrial end-systolic volume index; LVOTVTI = outflow tract velocity time integral). The data were analysed using IBM Statistical Product and Service Solution Version 22. Relationships between variables were determined using analysis of variance, Pearson correlation, and multiple linear regressions. Significance was assessed at p<0.05. Result It was discovered that the left atrial function index correlated with ejection fraction (r = 0.616, p = 0.001), fractional shortening (r = 0.462, p = 0.001), and the ratio of early transmitral flow to early myocardial contractility, E/E' (r = -0.522, p = 0.001). However, there was no correlation with stroke volume (r = 0.38, p = 0.11); the ratio of early transmitral flow to late transmitral flow, E/A (r = -0.10, p = 0.11); isovolumetric relaxation time, IVRT (r = -0.171, p = 0.11); and tricuspid annular plane systolic excursion, TAPSE (r = 0.185, p = 0.10). Of the variables that correlated with left atrial function index, left ventricular ejection fraction and the ratio of early transmitral flow to early myocardial contractility (E/E') were found to be independent predictors of left atrial function index. Conclusion Left ventricular ejection fraction and the ratio of early transmitral flow to early myocardial contractility reflect changes in the left atrial function index, and as such, they should be used as surrogates for its assessment, especially in low- and medium-income countries where left atrial function index estimation is not routinely done.

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.

Nonthrombogenic Roles of the Left Atrial Appendage: JACC Review Topic of the Week

The atrial appendage (LAA) is a well-established source of cardioembolism in patients with atrial fibrillation. Therefore, research involving the LAA has largely focused on its thrombogenic attribute and the utility of its exclusion in stroke prevention. However, recent studies have highlighted several novel functions of the LAA that may have important therapeutic implications. In this paper, we provide a concise overview of the LAA anatomy and summarize the emerging data on its nonthrombogenic roles.

The impact of upright posture on left ventricular deformation in athletes

Besides LV ejection fraction (LVEF), global longitudinal strain (GLS) and global myocardial work index (GWI) are increasingly important for the echocardiographic assessment of left ventricular (LV) function in athletes. Since exercise testing is frequently performed on a treadmill, we investigated the impact of upright posture on GLS and GWI. In 50 male athletes (mean age 25.7 ± 7.3 years) transthoracic echocardiography (TTE) and simultaneous blood pressure measurements were performed in upright and left lateral position. LVEF (59.7 ± 5.3% vs. 61.1 ± 5.5%; P = 0.197) was not affected by athletes' position, whereas GLS (- 11.9 ± 2.3% vs. - 18.1 ± 2.1%; P < 0.001) and GWI (1284 ± 283 mmHg% vs. 1882 ± 247 mmHg%; P < 0.001) were lower in upright posture. Longitudinal strain was most frequently reduced in upright posture in the mid-basal inferior, and/or posterolateral segments. Upright posture has a significant impact on LV deformation with lower GLS, GWI and regional LV strain in upright position. These findings need to be considered when performing echocardiography in athletes.

Percutaneous left atrial appendage occlusion: impact on left atrial deformation indices

BACKGROUND

Percutaneous left atrial appendage occlusion (LAAO) is an accepted alternative to thromboprophylaxis in patients with atrial fibrillation (AF) who are: (i) intolerant to oral anticoagulation (OAC) (e.g. life-threatening haemorrhage), (ii) non-adherent to OAC, or (iii) at a high bleeding risk with OAC. Improvement in LA mechanics was shown post-LAAO in the LAFIT-LARIAT study, using the Lariat device. No significant change was seen in LA mechanics after LAAO with the Watchman device in the LAFIT-Watchman study. The impact of LAAO with the Amplatzer or Amulet device on LA deformation mechanics has not been investigated.

PURPOSE

To evaluate the impact of LAAO with the Amplatzer or Amulet device on echocardiographic LA deformation indices.

METHODS

All patients undergoing percutaneous LAAO from 2013 to 2021 at a single centre were included from an ongoing clinical registry. LA reservoir (ε_reservoir), conduit (ε_conduit) and contractile strain (ε_contractile) and strain rate (SR_reservoir, SR_conduit, SR_contractile) were assessed with two-dimensional speckle tracking echocardiography from an apical four-chamber view. Conduit and contractile strain and strain rates were only recorded for patients without AF at the time of echocardiography. Changes in LA deformation indices over time were compared with a linear mixed model.

RESULTS

28 LAAO recipients (mean age 73 ± 12 years, 68% male) were analysed. 5 (18%) patients had AF pre- or post-procedure. After a mean follow-up of 1.6 ± 1.4 months, the mean LA ε_reservoir increased from 10.15 ± 6.44% to 10.18 ± 8.72% (p = 0.985), the mean LA ε_conduit increased from 5.12 ± 5.48% to 5.31 ± 6.11% (p = 0.891) and the mean LA ε_contractile decreased from 5.14 ± 4.32% to 4.95 ± 5.30% (p = 0.898). During the same time interval, the mean LA SR_reservoir decreased from + 0.54 ± 0.23.s^- 1 to + 0.48 ± 0.43.s^- 1 (p = 0.566), the mean LA SR_conduit remained stable: -0.47 ± 0.41.s^- 1 to -0.47 ± 0.32.s^- 1 (p = 0.997) and the mean LA SR_contractile decreased from - 0.66 ± 0.50.s^- 1 to -0.55 ± 0.46.s^- 1 (p = 0.660).

CONCLUSION

No significant improvement in LA mechanical function was seen after LAAO with the Amplatzer or Amulet device. Different LAAO devices therefore appear to have divergent effects on LA deformation, the clinical implications of which may warrant further study.

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.

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.

Atrial cardiomyopathy: Diagnosis, clinical implications and unresolved issues in anticoagulation therapy

Atrial cardiomyopathy (AC) is an evolving pathophysiological entity that has expanded our understanding regarding the atrium and its role in arrhythmogenesis and cardiac thromboembolism. The pathological myocardium in AC promotes arrhythmogenesis through mechanical dysfunction (hypocontractility, fibrosis), adverse alterations of the endothelium and secretion of prothrombotic factors (IL-6, IL-8, TNF-a). 'Red flags', indicative of AC, can be recognized either non-invasively by electrocardiography, echocardiography and cardiac magnetic resonance imaging or invasively by high-density electroanatomical mapping as low bipolar voltage areas of the affected myocardium. Signs of AC have been strongly associated with an increased risk of ischemic stroke, even embolic strokes of undetermined source, regardless of the coexistence of atrial fibrillation (AF). The underlying existence of AC has been negatively correlated with the success rate of catheter ablation of AF. The clinical value of AC is the provision of a novel pathway regarding the potential mechanisms of cerebrovascular events of cardiac thromboembolic origin. In addition, AC may serve as a risk stratification tool to predict the long-term responders of AF catheter ablation.

Factors of Persistent Limited Exercise Tolerance in Patients after COVID-19 with Normal Left Ventricular Ejection Fraction

Exercise intolerance de novo is one of the most common reported symptoms in patients recovering from the Coronavirus Disease 2019 (COVID-19). The present study determines etiological and pathophysiological factors influencing the mechanism of impaired exercise tolerance in patients during Long-COVID. Consequently, the factors affecting the percentage predicted oxygen uptake at peak exercise (%VO2pred) in patients after COVID-19 with a normal left ventricular ejection fraction (LVEF) were assessment. A total of 120 patients recovering from COVID-19 at three to six months after confirmed diagnosis were included. The clinical examinations, laboratory test results, echocardiography, non-invasive body mass analysis, and spiroergometry were evaluated. The subjects were divided into the following groups: study patients’ group with worsen oxygen uptake (%VO2pred < 80%; n = 47) and control group presenting%VO2pred ≥ 80% (n = 73). ClinicalTrials.gov Identifier: NCT04828629. The male gender and the percent of total body water content (TBW%) were significantly higher in the study group compared to the control group (53 vs. 29%, p = 0.007 and 52.67 (±6.41) vs. 49.89 (±4.59), p = 0.02; respectively). Patients with %VO2pred < 80% presented significantly lower global peak systolic strain (GLPS), tricuspid annular plane systolic excursion (TAPSE), and late diastolic filling (A) velocity (19.34 (±1.72)% vs. 20.10 (±1.35)%, p = 0.03; 21.86 (±4.53) vs. 24.08 (±3.20) mm, p = 0.002 and median 59.5 (IQR: 50.0−71.0) vs. 70.5 (IQR: 62.0−80.0) cm/s, p = 0.004; respectively) compared to the controls. The results of the multiple logistic regression model show that (A) velocity (OR 0.40, 95%CI: 0.17−0.95; p = 0.03) and male gender (OR 2.52, 95%CI: 1.07−5.91; p = 0.03) were independently associated with %VO2pred. Conclusions: Men have over twice the risk of persistent limited exercise tolerance in Long-COVID than women. The decreased (A) velocity, TAPSE, GLPS, and hydration status are connected with limited exercise tolerance after COVID-19 in patients with normal LVEF.

Differing Impact of Preterm Birth on the Right and Left Atria in Adulthood

Background Preterm birth affects 10% of live births and is associated with an altered left ventricular and right ventricular phenotype and increased cardiovascular disease risk in young adulthood. Because left atrial (LA) and right atrial (RA) volume and function are known independent predictors of cardiovascular outcomes, we investigated whether these were altered in preterm-born young adults. Methods and Results Preterm-born (n=200) and term-born (n=266) adults aged 18 to 39 years underwent cardiovascular magnetic resonance imaging. LA and RA maximal and minimal volumes (absolute, indexed to body surface area, and as a ratio to ventricular volumes) were obtained to study atrial morphology, while LA and RA stroke volume, strain, and strain rate were used to assess atrial function. Secondary analyses consisted of between-group comparisons based on degree of prematurity. Absolute RA volumes and RA volumes indexed to right ventricular volumes were significantly smaller in preterm-born compared with term-born adults. In addition, RA reservoir and booster strain were higher in preterm-born adults, possibly indicating functional compensation for the smaller RA volumes. LA volumes indexed to left ventricular volumes were significantly greater in preterm-born adults as compared with term-born adults, although absolute LA volumes were similar between groups. LA and RA changes were observed across gestational ages in the preterm group but were greatest in those born very-to-extremely preterm. Conclusions Preterm-born adults show changes in LA and RA structure and function, which may indicate subclinical cardiovascular disease. Further research into underlying mechanisms, opportunities for interventions, and their prognostic value is warranted.

Left ventricular function before and after percutaneous patent ductus arteriosus closure in preterm infants

BACKGROUND

Definitive closure of the patent ductus arteriosus (PDA) is associated with significant changes in the loading conditions of the left ventricle (LV), which may lead to cardiovascular and respiratory instability. The objective of the study was to evaluate targeted neonatal echocardiography (TnECHO) characteristics and the clinical course of preterm infants ≤2 kg undergoing percutaneous PDA closure.

METHODS

Retrospective cohort study of prospectively acquired pre- and post-closure TnECHOs to assess hemodynamic changes. Cardiorespiratory parameters in the first 24 h following PDA closure were also evaluated.

RESULTS

Fifty patients were included with a mean age of 30.6 ± 9.6 days and weight of 1188 ± 280 g. LV global longitudinal strain decreased from -20.6 ± 2.6 to -14.9 ± 2.9% (p < 0.001) after 1 h. There was a decrease in LV volume loading, left ventricular output, LV systolic and diastolic parameters. Cardiorespiratory instability occurred in 24 (48%) [oxygenation failure in 44%] but systolic hypotension and/or need for cardiovascular medications was only seen in 6 (12%). Patients with instability had worse baseline respiratory severity score and lower post-closure early diastolic strain rates.

CONCLUSIONS

Percutaneous PDA closure leads to a reduction in echocardiography markers of LV systolic/diastolic function. Post-closure cardiorespiratory instability is characterized primarily by oxygenation failure and may relate to impaired diastolic performance.

IMPACT

Percutaneous patent ductus arteriosus closure leads to a reduction in echocardiography markers of left ventricular volume loading, cardiac output, and left ventricular systolic/diastolic function. Post-procedural cardiorespiratory instability is characterized primarily by oxygenation failure. Post-procedural cardiorespiratory instability may relate to impaired diastolic performance.

Effect of mitral valve transcatheter edge-to-edge repair on indices of left atrial performance in chronic mitral regurgitation

INTRODUCTION

Effect of transcatheter edge-to-edge repair (TEER) using MitraClip in patients with mitral regurgitation (MR) on left atrial (LA) kinetic energy (LAKE), an index of LA work, and LA strain, a measure of LA performance, have not been well defined.

METHODS

Patients with chronic primary or secondary 3+ or 4+ MR were analyzed pre- and post-TEER using MitraClip. LAKE was determined by echocardiography using LA stroke volume and A-wave velocity. Peak atrial longitudinal strain (PALS), peak atrial strain in early diastole, and peak atrial contraction strain (PACS) were obtained by speckle tracking echocardiography.

RESULTS

Thirty-nine patients undergoing TEER with MitraClip were screened, 12 met criteria for analysis (9 primary and 3 secondary MR). Compared to pre-TEER, there was a significant increase post-TEER in LAKE (71.0 ± 64.1 vs. 177.5 ± 167.9 dyne·cm·10³ , respectively; p = .008) and Doppler transmitral A-wave velocity (87.8 ± 41.4 vs. 138.5 ± 43.7 cm/s, respectively; p < .001); LA stroke volume did not change significantly. Mitral valve mean gradient significantly increased post-TEER compared to pre-TEER (5.7 ± 2.1 vs. 3.3 ± 2.1 mmHg, respectively; p = .01). There was a trend toward decrease in PALS post-TEER compared to pre-TEER (16.2 ± 4.8 vs. 20.7 ± 9.9%, respectively; p = .05). Peak atrial strain in early diastole significantly decreased post-TEER compared to pre-TEER (7.2 ± 3.0 vs. 14.1 ± 7.2%; respectively, p < .001), while PACS did not significantly change (9.1 ± 3.5 vs. 6.7 ± 5.2%, respectively; p = .07).

CONCLUSION

In patients with chronic MR, LAKE increases after TEER with MitraClip driven by an increase in LA emptying velocities. Changes were also seen in LA strain with MitraClip. These procedurally induced changes due to mild mitral stenosis may have clinical implications.