Left Function Research Articles

Epigenetic regulation on left atrial function and disease recurrence after catheter ablation in atrial fibrillation

BackgroundGenetic variation and modifiable risk factors play a significant role in the pathogenesis of atrial fibrillation (AF). The influence of epigenetic modification on AF remains to be elucidated. We investigated the role of DNA methylation in the etiology of AF. Epigenetic evaluation was performed in 115 AF patients who underwent radiofrequency catheter ablation in a single institution. We measured methylation at approximately 850,000 bp cytosine-phosphate-guanine (CpG) sites in the 115 samples. The degree of methylation was compared across seven classification criteria: type of AF, late recurrence, impaired left atrium (LA) function, late gadolinium enhancement, LA diameter, LA volume, and flow velocity of the LA appendage.ResultsThe four most significantly methylated genes were DEFB104B, C3, TANC1, and TMEM9B. The DEFB104B gene (cg20223677 in the transcription start site), which encodes β-defensin 104B, was hypomethylated in three groups: AF patients with late recurrence, impaired LA function, and impaired LAA flow velocity. Enriched functional annotation of the differentially methylated datasets revealed that five out of the seven AF groups in this cohort were associated with genes involved in the cell movement of endothelial cell lines, sprouting angiogenesis by endothelial cell lines, or migration of endothelial cell lines.ConclusionsEpigenetic profiling revealed that epigenetic modification might affect important characteristics of AF. Our results suggest that the pathogenesis of AF might be affected by not only genetic variation or modifiable factors but also by epigenetic modulation.

Evaluation of left atrial function and the relationship between left atrial stiffness index and exercise capacity in hypertension-related heart failure with preserved ejection fraction

ObjectiveThe left atrial stiffness index (LASI) holds significance in the atrioventricular coupling function and heart failure progression. To assess left atrial function and evaluate the relationship between LASI and exercise capacity in hypertension-related heart failure with preserved ejection fraction (HT-HFpEF).MethodsThe study involved 62 healthy subjects and 163 patients with HT (112 patients in simple HT group and 51 patients in HT-HFpEF group). Each patient performed exercise stress test and standard ultrasonic images were evaluated. A comprehensive evaluation of atrioventricular function, along with investigation into the correlation between these functional parameters and exercise capacity. And further to investigate the feasibility of predicting exercise intolerance using three-dimensional derived left atrial strain index (LASI) (E/e'/LASr and E/e'/LASr-c).ResultsCompared to healthy subjects, HT group demonstrated the elevation in left atrial volume accompanied by decrease in strain value (P < 0.05). In HT-HFpEF group, further significant reductions were observed in both longitudinal (LASr) and circumferential strain (LASr-c, LASct-c) (P < 0.05). Univariate regression demonstrated that both E/e'/LASr and E/e'/LASr-c were significantly correlated with metabolic equivalents (METs) (r = −0.462, P < 0.001; r = −0.381, P < 0.001). The E/e'/LASr demonstrates comparable diagnostic efficacy to exercise-E/e' in assessing exercise intolerance in HT-HFpEF patients (AUC: 0.836 vs. 0.867, P = 0.239).ConclusionProgressive LA remodeling contributes to decreased atrioventricular compliance in HT and HT-HFpEF patients.E/e'/LASr serves as an independent indicator of exercise intolerance in patients with HT-HFpEF.

Utility of Simultaneous Left Atrial Strain–Volume Relationship During Passive Leg Lift to Identify Elevated Left Ventricular Filling Pressure—A Proof-of-Concept Study

Background: The assessment of left ventricular (LV) filling pressure in heart failure (HF) poses a diagnostic challenge, as HF patients may have normal LV filling pressures at rest but often display elevated LV filling pressures during exercise. Rapid preload increase during passive leg lift (PLL) may unmask HF in such challenging scenarios. We explored the dynamic interplay between simultaneous left atrial (LA) function and volume using LA strain/volume loops during rest and PLL and compared its diagnostic performance with conventional echocardiographic surrogates to detect elevated LV filling pressure. Methods: We retrospectively reviewed 35 patients with clinical HF who underwent simultaneous echocardiography and right heart catheterization before and immediately after PLL. Patients with atrial fibrillation (n = 4) were excluded. Twenty age-matched, healthy controls were added as controls. LA reservoir strain (LASr) was analyzed using speckle-tracking echocardiography. LA strain–volume loops were generated, including the best-fit linear regression line employing simultaneous LASr and LA volume. Results: LA strain–volume slope was lower for HF patients when compared with controls (0.71 vs. 1.22%/mL, p < 0.001). During PLL, the LA strain–volume slope displayed a moderately strong negative correlation with invasive pulmonary arterial wedge pressure (PAWP) (r = −0.71, p < 0.001). At a 0.74%/mL cut-off, the LA strain–volume slope displayed 88% sensitivity and 86% specificity to identify elevated PAWP (AUC 0.89 [0.76–1.00]). In comparison, LASr demonstrated strong but numerically lower diagnostic performance (AUC 0.82 [0.67–0.98]), and mitral E/e’ showed poor performance (AUC 0.57 [0.32–0.82]). Conclusions: In this proof-of-concept study, LA strain–volume characteristics provide incremental diagnostic value over conventional echocardiographic measures in the identification of elevated LV filling pressure.

The Effect of Training Experience on Cardiac Morphology in Resistance Exercise Practitioners: A Study on Left Ventricular Systolic and Diastolic Parameters and Left Atrium Mechanical Functions

Background and Objectives: Resistance exercises (REs) are a type of physical activity that individuals from many age groups have been doing recreationally, both as amateurs and professionally, in their daily lives in recent years. It is crucial to understand the effects of such sports on cardiac morphology in order to maximize the benefit of training and to tailor the training content accordingly. The aim of this study was to investigate the relationship between training experience (TE) and left ventricular (LV) systolic and diastolic parameters and left atrial (LA) mechanical function in healthy subjects who regularly performed RE for different durations. Materials and Methods: Forty-five healthy adults [age = 28.91 ± 10.30 years, height = 178.37 ± 5.49 cm, weight = 83.15 ± 13.91 kg, body mass index = 26.03 ± 3.42 kg/m2, TE = 7.28 ± 6.49 years] who performed RE between 1 year and 20 years were included in our study. The transthoracic echocardiograms (ECHOs) of the participants were evaluated by the cross-sectional research method, which is often used to understand the current situation in a given time period. Correlations between TE and LV systolic and diastolic parameters and LA mechanical function were analyzed. Results: As a result, interventricular septal thickness (IVS; r = 0.33, p = 0.028), the aortic diameter systole (ADs; r = 0.56, p < 0.001), and aortic diameter diastole (ADd; r = 0.58, p < 0.001) were positively correlated with TE, indicating associations with increased left ventricular (LV) hypertrophy and reduced ventricular compliance, while the aortic strain (AS; r = −0.44, p = 0.002), aortic distensibility (AD; r = −0.62, p < 0.001), and diastolic flow parameters including E (r = −0.41, p = 0.005), E/A (r = −0.38, p = 0.011), and E/Em (r = −0.31, p = 0.041) were negatively correlated with TE, reflecting impairments in diastolic function. Conclusions: This study showed that diastolic parameters were adversely affected in chronic RE. Therefore, we think that these individuals may have decreased relaxation and filling functions of the heart, which may also reduce adequate oxygen and nutrient delivery to the tissues. In this context, cohort studies are needed to analyze in detail the reasons for the decrease in diastolic parameters in these individuals.

Assessment of atrial strain variations in amateur runners: A 10-week unsupervised training program and half-Marathon impact study using 2D and speckle-tracking echocardiography

BackgroundCompetitive running leads to cardiac remodeling and functional changes in cardiovascular haemodynamics in professional runners. Data on atrial changes in amateur runners completing a half-marathon are limited. The study sought to analyze the impact of training and a 21.0975-km run on echocardiographic parameters of left (LA) and right (RA) atrial anatomy and function in recreational runners. MethodsThe study group comprised 52 amateur runners [mean age 32.96 (5.12) years], including 32 men. Echocardiographic evaluations were performed at three stages: prior to the ten-week unsupervised training, and then before and after the run. Morphological and functional parameters were assessed using two-dimensional imaging, Doppler, and speckle-tracking technique. ResultsDuring the training period, both LA dimension [31.87 mm vs. 33.96 mm; p < 0.001] and LA volume [59.00 ml vs. 68.00 ml; p < 0.001] increased and no changes were found for RA morphological parameters. Ten weeks of preparatory training resulted in an increase in LA contractile strain (LASct) [10.50 % vs. 11.00 %; p = 0.030], without affecting the RA function. Change of LASct was particularly pronounced in young women (<32 years; p = 0.029). Half-marathon performance decreased the LA volume. ConclusionsAmateur training for 21.0975-km run remodels LA and enhances LA active contractile function (especially in young women) without influencing RA. The half-marathon decreases LA volume and does not affect RA morphology and function in recreational runners.

Progress of echocardiography in the evaluation of left atrial function in patients with heart failure with preserved ejection fraction: a narrative review.

About half of all heart failures are heart failures with preserved ejection fraction (HFpEFs). As the population ages and metabolic disorders become more common, the prevalence of HFpEF continues to increase annually. Patients with HFpEF typically show a decline in various reserve capacities after exercise. According to recent research, patients with HFpEF may have significant clinical symptoms due to left atrial (LA) dysfunction. Patients with HFpEF may benefit greatly from the early detection of LA myocardial damage using echocardiographic measurements, particularly LA strain. This article examined state-of-the-art echocardiography as it relates to the assessment of LA function in patients with HFpEF. Databases such as PubMed, Google Scholar, and Baidu Scholar were searched to retrieve the latest articles on research advances in the field from 1998 to 2024. The article searches were not limited by rigid language or publication date constraints. This article outlines LA strain measurements using echocardiography, and provides the current normal reference range for LA strain values. Further, the features of differences in LA strain during exercise and rest are outlined for HFpEF patients in varying stages of heart failure. Finally, the clinical significance of LA strain in HFpEF is highlighted, including its substantial advantages in diagnosing diastolic dysfunction and left ventricular filling pressures, as well as its diagnostic and prognostic utility and potential as a therapeutic target. When evaluating the structure and function of the left atrium in patients with HFpEF, echocardiography shows a great deal of clinical promise. Specifically, LA strain may provide additional useful information for the early identification of LA dysfunction in HFpEF patients. The measurement of LA size is currently the only clinical test available for evaluating the left atrium in individuals with HFpEF. This review will enable ultrasonographers and physicians to better understand the clinical utility of LA strain in patients with HFpEF, and also provides important resources for future LA strain-related scientific research and clinical practice.

Three-dimensional echocardiographic evaluation of left atrial function in patients with dilated cardiomyopathy

Three-dimensional echocardiographic evaluation of left atrial function in patients with dilated cardiomyopathy

Genetic Determinants of Left Atrial Function Are Associated With Stroke.

While atrial fibrillation (AF) is a key risk factor for stroke, recent studies have suggested that atrial cardiomyopathy may also increase stroke risk in the absence of AF. This study aimed to evaluate genetic determinants for left atrial (LA) function and volumes and risk of stroke. Polygenic scores (PGSs) for LA measures were constructed and used in 380 017 individuals in the UK Biobank, without history of ischemic stroke, systemic arterial embolism, or AF at enrollment. Risk of ischemic stroke was estimated using time-to-event models, considering all-cause death and incident AF as competing events. Systemic arterial embolism was investigated as a secondary end point. The PGS for LA passive emptying fraction was associated with risk of ischemic stroke. Individuals with a PGS for LA passive emptying fraction in the lowest quartile had a hazard ratio (HR) of 1.12 for ischemic stroke compared with those in the top quartile (P=0.004). These associations were robust in a subgroup free of prevalent cardiovascular disease at baseline (HR for lowest quartile versus top quartile, 1.22; P<0.001). No associations were found for 4 other PGSs for LA measures or for risk of systemic arterial embolism. Two-sample Mendelian randomization was conducted between LA measures and cardioembolic stroke and indicated a protective effect of higher LA functional measurements. The PGS for LA passive emptying fraction was significantly associated with incident ischemic stroke when considering AF as a competing risk. Consistent results were found in Mendelian randomization analyses. These findings suggest that atrial dysfunction may influence stroke risk independently of AF.

Association of Coagulation Factor XI Level With Cardiovascular Events and Cardiac Function in Community-Dwelling Adults: From ARIC and CHS.

Coagulation factor XI (FXI) inhibitors are a promising and novel class of anticoagulants, but a recent animal study found that FXI inhibition exacerbated diastolic dysfunction and heart failure (HF). In the ARIC study (Atherosclerosis Risk in Communities), we investigated whether plasma FXI level was associated with cardiovascular events and cardiac function. ARIC was our primary analytic cohort. We included 4471 participants (median age, 75 years; 57% female; 17% Black) who attended visit 5 (2011-2013) with Somalogic-quantified plasma FXI levels and echocardiographic cardiac function. Prevalent HF and atrial fibrillation (AF) cases were defined as having HF or AF diagnosed at or before each participant's visit 5 exam date. Incident HF and AF events were ascertained through 2021. Associations were assessed using Cox, logistic, and linear regression models. Primary prospective associations were also validated in the CHS (Cardiovascular Health Study) using an orthogonal FXI assay (enzyme-linked immunosorbent assay). At ARIC visit 5, there were 665 and 419 participants with prevalent HF and AF, respectively. During a median follow-up of 9 years, there were 580 and 788 incident HF and AF events, respectively. Lower FXI level was associated prospectively with higher incidence of HF (hazard ratio [HR], 1.36 [for each 1-unit decrement of log2-transformed FXI level] [95% CI, 1.01-1.83]) but not incident AF, and cross-sectionally with increased odds of AF (odds ratio [OR], 1.96 [95% CI, 1.23-3.07]) but not HF. In age-stratified analyses, decreased FXI was associated with higher incidence of HF in participants ≥75 years of age (HR, 1.57 [95% CI, 1.08-2.28]) but not <75 years of age (HR, 1.11 [95% CI, 0.68-1.79]). The inverse FXI-HF association was validated in CHS (HR, 1.18 [95% CI, 1.02-1.36]). At ARIC visit 5, lower FXI level was also associated with higher prevalence of diastolic dysfunction and worse E/A ratio, left atrial (LA) volume index, LA function, and left ventricular mass index, but not left ventricular ejection fraction or global longitudinal strain. Decreased FXI level is associated with greater incidence of HF, especially in older adults. It is also associated with prevalent AF, worse diastolic function, worse LA function, and greater LA size. More research is needed to assess potential unwanted effects of FXI inhibition on the risk of cardiovascular events and cardiac function.

Association of left atrial function with vascular brain injury: The Atherosclerosis Risk in Communities study.

Lower left atrial (LA) function is associated with higher dementia risk and may be mechanistically linked through vascular brain injury, an established correlate for higher dementia risk. Using data from the Atherosclerosis Risk in Communities study, we assessed the cross-sectional association between LA function and brain magnetic resonance imaging (MRI) markers of vascular brain injury. We included 1488 participants who were free of prevalent dementia, stroke, or atrial fibrillation and who underwent a two-dimensional echocardiogram and brain MRI in 2011-2013 (mean [± standard deviation] age 76 [± 5] years, 60% female, 27% Black). LA function measures (reservoir, conduit, contractile strain) were assessed in quartiles. Brain MRI measures included cerebral microbleeds, brain infarcts, and white matter hyperintensity (WMH) volume. Logistic regression was used for dichotomous outcomes. Linear regression was used for WMH volume. Overall, 343 (23%) and 344 participants (23%) had ≥1 cerebral microbleed or brain infarct. After multivariable adjustments, the lowest LA reservoir and conduit strain quartiles (vs. highest quartile) were associated with higher odds of the presence of ≥1 cerebral microbleed (odds ratios [95% confidence intervals] 1.78 [1.42-2.22] and 1.52 [1.22-1.90]). Compared to the highest quartile, participants in the lowest LA conduit strain quartile had 1.51 (95% confidence interval 1.22-1.88) times higher odds of having ≥1 brain infarct. Lower LA contractile strain was associated with lower odds of brain infarcts. No association with WMH volume was noted. We found that LA reservoir and conduit strain were associated with cerebral microbleeds and brain infarcts. Lower LA function may be linked to dementia risk via vascular brain injury. Prospective studies are needed to confirm these findings.

Exploring risk Indicators of atrial fibrillation in severe Obesity: Left atrial cardiomyopathy and premature atrial contractions

BackgroundAlthough obesity is a major risk factor for atrial fibrillation (AF), its mechanisms and the diagnostic yield of AF screening in severe obesity is unclear. This study aims to enhance our comprehension of AF susceptibility in severe obesity by investigating associations between left atrial (LA) cardiomyopathy and premature atrial contractions (PACs) and to explore the diagnostic yield of AF screening. MethodsThis cross-sectional study included a total of 192 subjects aged 35–65 years with a BMI ≥ 35 kg/m2, alongside 50 non-obese controls, both without known cardiac disease. Prolonged heart rhythm registration was done with either 24-hours (n = 147) or 7-day Holter monitoring (n = 75) or an implantable loop recorder (ILR) (n = 10). Furthermore, we performed conventional transthoracic echocardiography and strain analyses. ResultsIn the obese cohort, LA enlargement was independently associated with PAC frequency. Each SD increment (10 ml/m2) of LA volume index corresponded with a 46 % increase in PACs. An increase of each SD (10 %) LA reservoir strain was associated with a decrease of 16 % in PAC frequency. There was no association found between LA cardiomyopathy and PACs in the control group. AF was not detected in any subject. ConclusionLA enlargement was independently associated with more frequent PACs in severe obesity, a well-known AF precursor. There was a noticeable trend suggesting a relation between impaired LA function and PACs. Considering our observed low diagnostic yield of AF screening within this population, further investigation is needed to determine whether incorporating LA cardiomyopathy as an additional risk measure could improve AF screening strategies for individuals with severe obesity.

Effect of Blood Pressure Control on Left Atrial Function Assessed by 2D Echocardiography in Newly Diagnosed Patients with Systemic Hypertension

Effect of Blood Pressure Control on Left Atrial Function Assessed by 2D Echocardiography in Newly Diagnosed Patients with Systemic Hypertension

Abstract 4125500: Obesity-Related Left Atrial Functional Change Becomes Apparent in Infancy

Background: Impaired left atrial (LA) function is observed in obese patients, however, there is little information on when LA dysfunction begins to appear. To clarify this issue, we assessed LA volume and function in obese infants. Methods: Two-dimensional speckle-tracking echocardiography was performed in 96 infants aged 4 months. Subjects were divided into 3 groups according to body mass index (BMI): normal (n=53), &lt;17 kg/m 2 ; overweight (n=28), 17 to 19.9 kg/m 2 ; obese (n=15), ≧20 kg/m 2 . LA maximal volume, LA minimal volume, and LA pre-atrial contraction volume and LA longitudinal strain (reservoir, conduit, and booster) were measured. LA total emptying fraction, passive emptying fraction, and active emptying fraction were calculated. Results: Systolic blood pressure was significantly higher in the obese group than in the normal group (Table). LA maximal volume, minimal volume, and pre-atrial contraction volume increased significantly with increasing BMI (r = 0.53, 0.54, and 0.63, respectively, p &lt;0.01). Compared with the normal group, reservoir LA strain was significantly lower in the overweight and obese groups. Conduit LA strain and passive emptying fraction were significantly lower in the overweight and obese groups than those in the normal group (Table). Reservoir LA strain, conduit LA strain, and passive emptying fraction decreased significantly with increasing BMI (r = -0.28, -0.27, and -0.33, respectively, p &lt;0.01). There was no significant difference in booster LA strain among the 3 groups. Compared with the normal group, LA active emptying fraction was significantly higher in the obese group (Table). Conclusions: Higher BMI is associated with impaired reservoir and conduit LA function and higher booster LA pump function, which may be compensatory. Thus, obesity-related changes in LA functional begin to appear in infancy. Our data support prevention of obesity in early childhood because higher BMI is responsible for significant changes in LA function in early life.

Abstract 4145861: Systemic Sclerosis is Associated with Sub-Clinical Abnormalities in Myocardial Energetics, Perfusion and Increased Fibrosis

Background: Primary cardiac involvement in systemic sclerosis (SSc) is heterogenous, poorly defined and associated with significant cardiac morbidity and mortality. The underlying mechanism is not well understood but may include the impact of coronary microvascular dysfunction and myocardial inflammation. Myocardial cellular metabolic alterations in SSc are yet to be established. Aims: Using 31 Phosphorous magnetic resonance spectroscopy ( 31 P MRS) and cardiovascular magnetic resonance (CMR), we aimed to establish if myocardial energetics, measured as phosphocreatine (PCr) /ATP ratio, and quantitative myocardial perfusion were reduced in individuals with SSc compared to healthy volunteers (HV). Methods: A total of 35 age and sex matched participants were recruited (25 SSc, 10 HV). All subjects underwent 31 P MRS and comprehensive CMR protocol including volumetric analysis, quantitative myocardial perfusion and T1 mapping. Results: Table-1 shows clinical and CMR / 31 P MRS data. Bi-ventricular volumes, systolic function and left atrial function were similar in both groups. NT-Pro BNP and myocardial extra cellular volume (ECV) were significantly increased in SSc. Both PCr/ATP and myocardial perfusion reserve (MPR) were significantly reduced in SSc compared with controls. The disease activity as measured by the European Scleroderma Trials and Research group (EUSTAR) activity index did not correlate with either NTproBNP (P=0.79), PCr/ATP (P=0.35) or MPR (P=0.6). Conclusions: In addition to validating our previous observations of reduced perfusion and increased myocardial fibrosis in SSc, we have demonstrated for the first time significant reductions in myocardial energetics in patients with SSc. These findings provide further valuable insight into the pathogenesis of primary myocardial disease in SSc.

Left Atrial Structure and Function Following Ethanol Infusion into Vein of Marshall (MR-SHALL Study).

Ethanol infusion into the vein of Marshall (EI-VOM) is an adjunctive therapy to pulmonary vein isolation (PVI), which improves the efficacy of persistent atrial fibrillation (AF) ablation procedures. It is unknown how EI-VOM scar formation impacts left atrium (LA) structure and function. To characterize scar formation after EI-VOM, and its impact on LA function, by cardiac magnetic resonance (CMR). Consecutive patients referred for persistent AF ablation, or any repeat procedure, were included. Ablation strategy included PVI, EI-VOM and linear lesions when deemed necessary. LA was assessed by late gadolinium enhancement (LGE) CMR at baseline and 3-month follow-up. CMR was post-processed off-line with dedicated software. The LA was regionalized into 17 segments, and global and regional scarring were calculated. Strain parameters were analyzed-including LA reservoir, conduit, and booster strain; LA ejection fraction; and LA passive and active emptying function. Follow-up LGE-CMR reconstruction was coregistered with the voltage map, ablation RF points, and fluoroscopy to compare the scar location with the VOM trajectory. This study included 21 patients (65 ± 8 years; 76% men; 57% ablation of persistent AF). After EI-VOM, 95% of patients presented new low-voltage areas, all of whom exhibited new LGE-CMR scarring at follow-up. Voltage map and LGE-CMR coregistration showed comparable scar areas (p = 0.287). LGE-CMR scarring frequently involved the whole VOM trajectory, predominantly affecting the LA ridge, mitral isthmus, and left posterior wall. LA volume was significantly reduced after ablation, without significant changes in LA functional parameters. EI-VOM causes permanent scarring at 3-month follow-up, with no adverse impact on CMR LA functional parameters.

Multiphysics simulations reveal haemodynamic impacts of patient-derived fibrosis-related changes in left atrial tissue mechanics.

Stroke is a leading cause of death and disability worldwide. Atrial myopathy, including fibrosis, is associated with an increased risk of ischaemic 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 multiphysics simulations of left atrial (LA) myocardial motion and haemodynamics 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 multifactorial behaviour is observed. This work illustrates how high-fidelity, multiphysics models can be used to study thrombogenesis mechanisms in patient-specific anatomies, shedding light onto the links between atrial fibrosis and ischaemic stroke. KEY POINTS: Left atrial (LA) fibrosis is associated with arrhythmogenesis and increased risk of ischaemic 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 improved by incorporating patient-specific information such as fibrotic maps and haemodynamic patterns. We present the first electro-mechano-fluidic multiphysics 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.

Left atrial function during exercise stress echocardiography as a sign of paroxysmal/persistent atrial fibrillation

ObjectiveAtrial cardiomyopathy is closely associated with atrial fibrillation (AF), and some patients exhibit no dysfunction at rest but demonstrate evident changes in left atrial (LA) function and LA volume during exercise. This study aimed to identify distinguishing signs during exercise stress echocardiography (ESE) among patients in sinus rhythm (SR), with and without history of paroxysmal/persistent AF (PAF).MethodsA prospective cohort of 1055 patients in SR was enrolled across 12 centers. The main study cohort was divided into two groups: the modeling group (n = 513) and the verification group (n = 542). All patients underwent ESE, which included B-lines, LA volume index (LAVi), and LA strain of the reservoir phase (LASr).ResultsAge, resting and stress LAVi and LASr, and B-lines were identified as a combination of detectors for PAF in both groups. In the entire cohort, aside from resting and stress LAVi and LASr, additional parameters differentiating PAF and non-PAF patients were the presence of systemic hypertension, exercise E/e’ > 7, worse right ventricle (RV) contraction during exercise (∆ tricuspid annular plane systolic excursion < 5 mm), a lower left ventricular contractile reserve (< 1.6), and a reduced chronotropic reserve (heart rate reserve < 1.64). The composite score, summing all 9 items, yielded a score of > 4 as the best sensitivity (79%) and specificity (65%).ConclusionESE can complement rest echocardiography in the identification of previous PAF in patients with SR through the evaluation of LA functional reservoir and volume reserve, LV chronotropic, diastolic, and systolic reserve, and RV contractile reserve.Graphical A scoring system predicting the probability of PAF. The score was computed using the cutoff values as in the illustration. The score >4 demonstrated a sensitivity of 79% and a specificity of 65% of PAF.

Atrial fibrillation substrate and impaired left atrial function: a cardiac MRI study.

Structural and fibrotic remodelling is a well-known contributor to the atrial fibrillation (AF) substrate. Epicardial adipose tissue (EAT) is increasingly recognized as a contributor through electrical remodelling in the atria. We aimed to assess the association of LA fibrosis and EAT with LA strain and function using cardiac magnetic resonance (CMR) imaging in patients with AF. LA fibrosis was assessed using late gadolinium enhancement CMR, LA EAT was assessed using the fat-water separation Dixon sequence, and feature tracking was applied to assess global longitudinal strain in its three components [reservoir (GLRS), conduit (GLCdS), and contractile (GLCtS)]. LA emptying fraction and LA volume were measured using the cine sequences. All CMR images were acquired in sinus rhythm. One hundred one AF patients underwent pre-ablation CMR (39% female, average age 62 years). LA fibrosis was negatively associated with the three components of global longitudinal strain (GLRS: R = -0.35, P < 0.001; GLCdS: R = -0.24, P = 0.015; GLCtS: R = -0.2, P = 0.046). Out of the different sections of the LA, fibrosis in the posterior and lateral walls was most negatively correlated with GLRS (R = -0.32, P = 0.001, and R = -0.33, P = 0.001, respectively). LA EAT was negatively correlated with GLCdS (R = -0.453, P < 0.001). LA fibrosis was negatively correlated with LA emptying fraction but LA EAT was not (R = -0.27, P = 0.007, and R = -0.22, P = 0.1, respectively). LA EAT and fibrosis were both positively correlated with LA volume (R = 0.38, P = 0.003, and R = 0.24, P = 0.016, respectively). LA fibrosis, a major component of the AF substrate, and EAT, an important contributor, are associated with a worsening LA function through strain analysis by CMR.

Significance of left atrial function in predicting early recurrence of atrial fibrillation following electrical cardioversion

Significance of left atrial function in predicting early recurrence of atrial fibrillation following electrical cardioversion

Left atrial functional changes associated with repeated catheter ablations for atrial fibrillation.

The impact of repeated atrial fibrillation (AF) ablations on left atrial (LA) mechanical function remains uncertain, with limited long-term follow-up data. This retrospective study involved 108 AF patients who underwent two catheter ablations with cardiac magnetic resonance imaging (MRI) done before and 3 months after each of the ablations from 2010 to 2021. The rate of change in peak longitudinal atrial strain (PLAS) assessed LA function. Additionally, a sub-study of 36 patients who underwent an extra MRI before the second ablation, gave us an additional time segment to evaluate the basis of change in PLAS. In the two-ablation, three MRI sub-study 1, the PLAS percent change rate was similar before and after the first ablation (r11 = -0.9 ± 3.1%/year, p = 0.771). However, the strain change rate from postablation 1 to postablation 2 was significantly worse (r12 = -23.7 ± 4.8%/year, p < 0.001). In the sub-study 2 with four MRIs, all three rates were negative, with reductions from postablation 1 to pre-ablation 2 (r22 = -13.3 ± 2.6%/year, p < 0.001) and from pre-ablation 2 to postablation 2 (r23 = -8.9 ± 3.9%/year, p = 0.028) being significant. The present study suggests that the more ablations performed, the more significant the decrease in the postablation mechanical function of the LA. The natural progression of AF (strain change from postablation 1 to pre-ablation 2) had a greater negative influence on LA mechanical function compared to the second ablation itself suggesting that second ablation in patients with recurrence after first ablation is an effective strategy even from the LA mechanical function aspect.