Left atrial function in middle-aged men and women with and without paroxysmal atrial fibrillation: Data from the Akershus Cardiac Examination (ACE) 1950 study.

PURPOSE: To assess left atrial (LA) function in individuals with known paroxysmal atrial fibrillation (AF) compared with healthy and nonhealthy individuals without atrial fibrillation. METHODS: The Akershus Cardiac Examination 1950 Study included 3,706 individuals all born in 1950. LA strain assessment of reservoir (LASr), conduit (LAScd) and contractile (LASct) functions were performed in all participants by investigators blinded to clinical data. Participants with cardiovascular disease, obesity, diabetes, pulmonary or renal disease were defined as nonhealthy, and those without as healthy. Patients with paroxysmal AF were identified through medical history and ECG documentation. RESULTS: LA strain assessment was feasible in 3,229 (87%) of the participants (50% women). The healthy group (n = 758) had significantly higher LASr and LAScd than the nonhealthy (n = 2,376), but LASct was similar between the groups. Participants with paroxysmal AF had significantly lower values of all strain parameters than the other groups. Multivariable logistic regression showed a significantly reduced probability of having AF per standard deviation increase in LASr and LASct. A nonlinear restricted cubic spline model fitted better with the association of LASr with paroxysmal AF than the linear model, and LA strain values below the population mean associated with an increased probability of having AF, but for values above the population mean no such association was present. CONCLUSION: Compared to participants without AF, those with known paroxysmal AF had significantly lower values of all LA strain parameters during sinus rhythm. Lower values of LA strain were associated with a significantly increased probability of having AF.

Coronary microvascular dysfunction and atrial reservoir function.

BACKGROUND: Coronary microvascular dysfunction (CMD) refers to structural and functional abnormalities of the coronary microcirculation, which may be diagnosed using invasive coronary physiology. CMD is responsible for impaired diastolic cardiac function. It has recently been suggested that left atrial strain (LASr) represents a highly sensitive tool for detecting cardiac diastolic function abnormalities. Accordingly, the aim of this study was to investigate the relationship between CMD and LASr. METHODS: Consecutively enrolled patients with non-obstructed coronary arteries (NOCA) underwent CMD and LASr evaluation by invasive thermodilution and noninvasive echocardiography, respectively. RESULTS: Forty-two (42) patients were included, out of which 26 presented with CMD. There were no significant differences between CMD-positive and negative patients in terms of clinical and echocardiographic characteristics. LASr was significantly reduced in patients with CMD (24.6% ± 6.1 vs. 30.3 ± 7.8%, p = 0.01). A moderate correlation was observed between coronary flow reserve and LAsr (r = 0.47, p = 0.002). A multivariate logistic regression analysis demonstrated that CMD was independently associated with LASr (OR = 0.88, 95%CI 0.78-0.99.135, p = 0.04). A LASr cut-off of 25.5% enabled an optimal classification of patients with or without CMD. CONCLUSION: Patients with NOCA and CMD had a significantly reduced LASr compared with patients without CMD, suggesting the early impairment of diastolic function in these patients.

Conduit Flow Compensates for Impaired Left Atrial Passive and Booster Functions in Advanced Diastolic Dysfunction.

BACKGROUND: Quantification of left atrial (LA) conduit function and its contribution to left ventricular (LV) filling is challenging because it requires simultaneous measurements of both LA and LV volumes. The functional relationship between LA conduit function and the severity of diastolic dysfunction remains controversial. We studied the role of LA conduit function in maintaining LV filling in advanced diastolic dysfunction. METHODS: We performed volumetric and flow analyses of LA function across the spectrum of LV diastolic dysfunction, derived from a set of consecutive patients undergoing multiphasic cardiac computed tomography scanning (n=489). From LA and LV time-volume curves, we calculated 3 volumetric components: (1) early passive emptying volume; (2) late active (booster) volume; and (3) conduit volume. Results were prospectively validated on a group of patients with severe aortic stenosis (n=110). RESULTS: The early passive filling progressively decreased with worsening diastolic function (P<0.001). The atrial booster contribution to stroke volume modestly increases with impaired relaxation (P=0.021) and declines with more advanced diastolic function (P<0.001), thus failing to compensate for the reduction in early filling. The conduit volume increased progressively (P<0.001), accounting for 75% of stroke volume (interquartile range, 63-81%) with a restrictive filling pattern, compensating for the reduction in both early and booster functions. Similar results were obtained in patients with severe aortic stenosis. The pulmonary artery systolic pressure increased in a near-linear fashion when the conduit contribution to stroke volume increased above 60%. Maximal conduit flow rate strongly correlated with mitral E-wave velocity (r=0.71; P<0.0001), indicating that the increase in mitral E wave in diastolic dysfunction represents the increased conduit flow. CONCLUSIONS: An increase in conduit volume contribution to stroke volume represents a compensatory mechanism to maintain LV filling in advanced diastolic dysfunction. The increase in conduit volume despite increasing LV diastolic pressures is accomplished by an increase in pulmonary venous pressure.

The Clinical Applications of Left Atrial Strain: A Comprehensive Review.

Left atrial (LA) strain imaging, which measures the deformation of the LA using speckle-tracing echocardiography (STE), has emerged recently as an exciting tool to help provide diagnostic and prognostic information for patients with a broad range of cardiovascular (CV) pathologies. Perhaps due to the LA's relatively thin-walled architecture compared with the more muscular structure of the left ventricle (LV), functional changes in the left atrium often precede changes in the LV, making LA strain (LAS) an earlier marker for underlying pathology than many conventional echocardiographic parameters. LAS imaging is typically divided into three phases according to the stage of the cardiac cycle: reservoir strain, which is characterized by LA filling during systole; conduit strain, which describes LA deformation during passive LV filling; and booster strain, which provides information on the LA atrium during LA systole in late ventricular diastole. While additional large-population studies are still needed to further solidify the role of LAS in routine clinical practice, this review will discuss the current evidence of its use in different pathologies and explore the possibilities of its applications in the future.

Application value of real-time 3D speckle tracking imaging in left atrial function evaluation of patients with paroxysmal atrial fibrillation.

OBJECTIVE: To evaluate left atrial volume and function in patients with paroxysmal atrial fibrillation (AF) combined with left atrial appendage thrombosis and patients with paroxysmal AF without left atrial appendage thrombosis by 3-dimensional speckle tracking imaging (3D-STI), and to explore the application value of this set of parameters in the evaluation of left atrial function in patients with paroxysmal AF. MATERIALS AND METHODS: A total of 40 patients with paroxysmal AF admitted from December 2018 to December 2020 were selected as the observation group. All patients with paroxysmal AF in the observation group underwent transesophageal echocardiography. According to the presence of left atrial appendage thrombosis, the patients were divided into the AF without thrombosis group (24 cases) and the AF with thrombosis group (16 cases). Thirty normal people were selected as control group who were chosen as having no heart-related disease. The left atrial volume parameters (Left atrial maximum volume LAVmax, Left atrial minimum volume LAVmin, Left atrial volume before atrial contraction LAVpre-A, Left atrial stroke volume LAEV), left atrial ejection fraction (LAEF) and left atrial strain parameters (Left atrial reservoir longitudinal strain LASr, Left atrial conduit longitudinal strain LAScd, Left atrial contraction longitudinal strain LASct, Left atrial reservoir circumferential strain LASr-c, Left atrial conduit circumferential strain LAScd-c, Left atrial contraction circumferential strain LASct-c) of the 3 groups were measured by 3D-STI. RESULTS: With the progression of paroxysmal AF, the left atrial volume increased, and the reservoir, conduit and contractile function were damaged. The left atrial volume continued to increase, and the reservoir, conduit and contractile function further decreased significantly in patients with AF combined with left atrial appendage thrombosis. LAEF was positively correlated with LASr and LASr_c. CONCLUSION: Real-time 3-dimensional spot tracking imaging (3D-STI) can evaluate the changes in left atrial volume and function in patients with paroxysmal AF, and has a certain reference value for clinical judgment of disease progression and prognosis.

Diastolic Filling in Patients After Heart Transplantation Is Impaired Due to an Altered Geometrical Relationship Between the Left Atrium and Ventricle.

BACKGROUND: The geometrical relationship between atrial and ventricular short-axis cross-sectional area determines the hydraulic forces acting on intracardiac blood. This is important for diastolic filling. In patients undergoing heart transplantation (HTx), the left atrium is often enlarged as a result of the standard surgical technique. We hypothesized that diastolic filling in HTx patients is affected by the surgery altering the geometrical relationship between atrium and ventricle. METHODS AND RESULTS: This retrospective, cross-sectional study included 25 HTx patients (median age, 52 [range, 25-70] years), 15 patients with heart failure with reduced ejection fraction (median age, 63 [range, 52-75] years), 15 patients with heart failure with preserved ejection fraction (median age, 74 [range, 56-82] years), and 15 healthy controls (median age, 64 [range, 58-67] years) who underwent cardiac magnetic resonance imaging. Left ventricular, atrial, and total heart volumes (THV) were obtained. Atrioventricular area difference at end diastole and end systole was calculated as the largest ventricular short-axis area minus the largest atrial short-axis area. Left atrial minimum volume normalized for THV (LAmin/THV) was larger in HTx patients (median, 0.13 [range, 0.07-0.19]) compared with controls (median, 0.05 [range, 0.03-0.08], P <0.001), whereas left ventricular volume normalized for THV (left ventricular end-diastolic volume/THV) was similar between HTx and controls (median, 0.19 [range, 0.12-0.24] and median, 0.22 [range, 0.20-0.25], respectively). At end diastole, when atrioventricular area difference reached its largest positive value in controls, 11 HTx patients (44%) had a negative atrioventricular area difference, indicating impaired diastolic filling. CONCLUSIONS: Diastolic filling is impaired in HTx patients due to an altered geometrical relationship between the left atrium and ventricle. When performing cardiac transplantation, a surgical technique that creates a smaller left atrium may improve diastolic filling by aiding hydraulic forces.

Deep learning of left atrial structure and function provides link to atrial fibrillation risk.

Increased left atrial volume and decreased left atrial function have long been associated with atrial fibrillation. The availability of large-scale cardiac magnetic resonance imaging data paired with genetic data provides a unique opportunity to assess the genetic contributions to left atrial structure and function, and understand their relationship with risk for atrial fibrillation. Here, we use deep learning and surface reconstruction models to measure left atrial minimum volume, maximum volume, stroke volume, and emptying fraction in 40,558 UK Biobank participants. In a genome-wide association study of 35,049 participants without pre-existing cardiovascular disease, we identify 20 common genetic loci associated with left atrial structure and function. We find that polygenic contributions to increased left atrial volume are associated with atrial fibrillation and its downstream consequences, including stroke. Through Mendelian randomization, we find evidence supporting a causal role for left atrial enlargement and dysfunction on atrial fibrillation risk.

Correlation between circulating fibrosis biomarkers with left atrial function and left atrial volume index in rheumatic mitral stenosis.

Mitral stenosis is the most common rheumatic heart disease (RHD) disorder worldwide, including in Indonesia. This pathological condition causes left atrial pressure, leading to left atrial fibrosis that affects the structure and function of the left atrial as well as the clinical condition. The aim of this study was to assess the correlation between circulating fibrosis biomarkers with net atrioventricular compliance (Cn) as a parameter of left atrial function, and left atrial volume index (LAVI) as a parameter left atrium structure of changes. A cross-sectional study was conducted at Panti Rahayu Hospital and Permata Bunda Hospital, Purwodadi, Central Java, with a total of 40 RHD patients with severe mitral stenosis. The ELISA was used to measure the levels of carboxy-terminal propeptide of type I procollagen (PICP), matrix metalloproteinase I (MMP-1), tissue inhibitor matrix metalloproteinase 1 (TIMP-1), and transforming growth factor-ß1 (TGF-ß1). The left atrial function was assessed by measuring Cn, and the LAVI parameters were measured to assess left atrium structure/size. The mean levels of circulating fibrosis biomarkers were as follows: PICP 153.96±89.12 ng/mL; MMP-1 1.44±2.12 ng/mL; MMP-1/TIMP-1 ratio 0.38±0.54 and TGF-ß1 2.66±1.96 pg/mL. From the echocardiographic evaluation, the mean Cn was 5.24±1.93 mL/mmHg and the mean LAVI was 152.55±79.36 mL/m2. There were significant correlation between MMP-1 and MMP-1/TIMP-1 ratio with Cn (r=0.345 and r=0.333, respectively; both had p<0.05). PICP and TGF-ß1 biomarkers did not significantly correlate with Cn (p>0.05). Meanwhile, none of the biomarkers had a significant correlation with LAVI (p>0.05). This study highlights that MMP-1 and MMP-1/TIMP-1 ratio are potentially to be used as markers to determine the Cn in RHD patients with severe mitral stenosis. However, further studies with a higher sample size are needed to confirm this finding.

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

BACKGROUND: Cardiovascular magnetic resonance (CMR) extracellular volume (ECV) allows non-invasive detection of myocardial interstitial fibrosis, which may be related to diastolic dysfunction and left atrial (LA) remodeling in hypertrophic cardiomyopathy (HCM). While the prognostic role of LGE is well-established, interstitial fibrosis and LA dysfunction are emerging novel markers in HCM. This study aimed to explore the interaction between interstitial fibrosis by ECV, LA morpho-functional parameters and adverse clinical outcomes in selected low-risk patients with HCM. METHODS: 115 HCM patients and 61 matched controls underwent CMR to identify: i) interstitial fibrosis by ECV in hypertrophied left ventricular LGE-negative remote myocardium (r-ECV); ii) LA indexed maximum (LAVi max) and minimum (LAVi min) volumes, ejection fraction (LA-EF) and strain (reservoir εs, conduit εe and booster εa), by CMR feature-tracking. 2D-echocardiographic assessment of diastolic function was also performed within 6 months from CMR. A composite endpoint including worsening NYHA class, heart failure hospitalization, atrial fibrillation and all-cause death was evaluated at 2.3 years follow-up. HCM patients were divided into two groups, according to r-ECV values of controls. RESULTS: Patients with r-ECV ≥29% (n = 45) showed larger LA volumes (LAVimax 63 vs. 54 ml/m2, p < 0.001; LAVimin 43 vs. 28 ml/m2, p ã€ˆ0001), worse LA function (εs 16 vs. 28%, εe 8 vs. 15%, εa 8 vs. 14%, LA-EF 33 vs. 49%, all p < 0.001) and elevated Nt-proBNP (1115 vs. 382 pg/ml, p = 0.002). LA functional parameters inversely correlated with r-ECV (εs r = -0.54; LA-EF r = -0.46; all p < 0.001) and E/e' (εs r = -0.52, LA-EF r = -0.46; all p < 0.006). r-ECV ≥29% and LAVi min >30 ml/m2 have been identified as possible independent factors associated with the endpoint. CONCLUSIONS: In HCM diffuse interstitial fibrosis detected by increased r-ECV is associated with LA remodeling and emerged as a potential independent predictor of adverse clinical outcomes, on top of the well-known prognostic impact of LGE.

Prognostic value of left ventricular and left atrial strain imaging in moderate to severe aortic stenosis: Insights from an Asian population.

BACKGROUND: Data regarding the prognostic value of left atrial (LA) strain in aortic stenosis (AS) is scarce, especially in Asian population and moderate AS. METHOD: Left ventricular global longitudinal strain (LVGLS), LA reservoir strain (LASr), conduit strain (LAScd), and contractile strain (LASct) were measured using automated speckle-tracking echocardiography in consecutive patients with moderate or severe AS. The primary endpoint was a composite of all-cause death (ACD) and major adverse cardiovascular events (MACE; myocardial infarction, syncope, and heart failure hospitalization). RESULTS: Of 712 patients (mean age, 78 ± 12 years; 370 [52%] moderate AS; 342 [48%] severe AS), average LV ejection fraction (LVEF) was 68 with SD of 12%. At a median follow-up of 18 months (interquartile range, 11-26 months), the primary endpoint occurred in 93 patients (60 deaths and 35 MACEs) and 221 patients underwent surgical or transcatheter aortic valve replacement (AVR). In the entire cohort, separate multivariable models adjusted for age, Charlson index, symptomatic status, time-dependent AVR, AS-severity, LA volume index and LVEF demonstrated that only LASr was associated with MACE+ACD (Hazard ratio, 0.97; P = 0.014). Subgroup analysis for MACE+ACD demonstrated consistent prognostication for LASr in moderate and severe AS; LVGLS was prognostic only in severe AS (all P ≤ 0.023). The optimal MACE+ACD cutoff for LASr from spline curves was 21.3%. Adjusted Kaplan-Meier curves demonstrated better event-free survival in patients with LASr >21.3% versus those with LASr ≤21.3% (P = 0.04). CONCLUSIONS: In both moderate and severe AS, only LASr robustly predicted outcomes; thus, including LASr in the AS staging algorithm should be considered.

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

BACKGROUND: Left atrial (LA) dysfunction is involved in idiopathic inflammatory myopathy (IIM). Multiparametric cardiovascular magnetic resonance (CMR) strain imaging is a feasible and reproducible tool for examining global and regional LA functions, as well as left ventricular (LV) function in IIM patients. AIM: The aim of this study was to evaluate the feasibility and reproducibility of LA strain occurrence and strain rate for LA function assessment using CMR in IIM cases. MATERIALS AND METHODS: A total of 36 IIM and 42 healthy control cases were included. Baseline ventricular function was comparatively assessed in both groups. LA strain occurrence and strain rate were examined by cine cardiac magnetic resonance imaging [MRI] utilizing an in-house semiautomated technique. LA global function indexes were quantitated, including reservoir, conduit, and booster-pump functions. RESULTS: A total of 78 participants were enrolled in this study. There was no significant difference in left/right ventricular routine functions between IIM patients and control individuals (p>0.05); the same results (p>0.05) was also observed between patients with high hs-cTnI and normal. However, LV mass index had significant difference (p1=0.003, p2<0.01). Compared with IIM patients and control individuals, only total strain (εs) (p4=0.046) and passive strain (εe) (p4=0.002) showed significant difference, and in cases with high hs-cTnI and normal hs-cTnI, there are differences for εs (p3=0.012) and εe (p4=0.047). The strongest association was found between εe and LV ejection fraction (LVEF) (r=0.581, p<0.01). CONCLUSION: IIM cases have altered LA reservoir and conduit functions, and LA strain could reflect LA function.

Incremental diagnostic and prognostic utility of left atrial deformation in heart failure using speckle tracking echocardiography.

Left atrium (LA) is a very important component of cardiovascular performance. The assessment of LA function has gathered the interest with expanding research supporting the utility as a biomarker for outcomes in heart failure (HF). Echocardiography is the main imaging modality which helps in a qualitative and quantitative assessment of the LA size and function. Recent advances in probe technology and software analysis have provided a better understanding of LA anatomy, physiology, pathology, and function. A variety of parameters have been defined as markers of LA function but there is no single parameter that best defines LA function. Speckle tracking echocardiography-derived analysis of LA deformation provides a window on all phases of LA function (reservoir, conduit, and booster pump). There is accumulative published data that supported the diagnostic and prognostic values of LA deformation integration during echo assessment of LA in HF. This review article summarized the clinical utility of LA deformation that may help in prediction, diagnosis, categorization, risk stratification, and guiding the proper selection of therapy in HF patients in daily practice.

Reference intervals for various measurements of canine left atrial size and function obtained using two-dimensional and three-dimensional echocardiography.

BACKGROUND: Many canine cardiac diseases are associated with left atrial (LA) remodeling and decreased function. For accurate assessment of LA indices, large-scale and prospectively determined reference intervals are necessary. OBJECTIVES: To generate reference intervals of LA size and function using two-dimensional and three-dimensional echocardiography. ANIMALS: Two hundred and one healthy adult dogs. METHODS: Left atrial volume was assessed in right parasternal long-axis, left apical four-chamber and two-chamber views using monoplane Simpson's method, two-dimensional and three-dimensional speckle tracking. Additionally, LA diameter was measured in right parasternal short-axis and long-axis views. Furthermore, LA function was determined by measuring strain and calculating LA fractional shortening and ejection fraction. All variables were tested for correlation to heart rate, age, and body weight. For LA diameter and volume, scaling exponents and prediction intervals were generated using allometric scaling. Reference intervals for LA function parameters were calculated using nonparametric methods. RESULTS: Left atrial diameter and volume showed a strong correlation with body weight. The scaling exponent for LA diameter was approximately 1/3 (0.34-0.40) and approximately one for volume measurements (0.97-1.26). Parameters of LA function showed no clinically relevant correlation with body weight, except for two variables, which showed a mild negative correlation. No clinically relevant correlations with age or heart rate were found. CONCLUSIONS: Reference intervals for linear, two-dimensional and three-dimensional measurements of LA size and function were established. The wide range of measurement methods offers the opportunity to select the appropriate reference values for LA evaluation depending on the available technical possibilities.