Change in left atrial function predicts incident atrial fibrillation: the Multi-Ethnic Study of Atherosclerosis

Echocardiography predictors of sustained sinus rhythm after cardioversion of supraventricular arrhythmia in patients with septic shock

PURPOSE

The echocardiography parameters may predict the maintenance of sinus rhythm after cardioversion of a supraventricular arrhythmia (SVA).

MATERIALS AND METHODS

Patients in septic shock with onset of an SVA, normal to moderately reduced LV systolic function (EF_LV˃̳35%) and on a continuous noradrenaline of <1.0 μg/kg.min were included. Echocardiography was performed at the arrhythmia onset, 1 h and 4 h post cardioversion on an infusion of propafenone or amiodarone.

RESULTS

Cardioversion was achieved in 96% of the 209 patients within a median time of 6(1.8-15.6)h, 134(64.1%) patients experienced at least one SVA recurrence after cardioversion. At 4 h the left atrial emptying fraction (LA_EF, cut-off 38.4%, AUC 0.69,p˂0.001), and transmitral A wave velocity-time-integral (Avti, cut-off 6.8 cm, AUC 0.65,p = 0.001) showed as limited predictors of a single arrhythmia recurrence. The LA_EF 44(36,49)%, (p = 0.005) and the Avti 8.65(7.13,9.50)cm, (p < 0.001) were associated with sustained sinus rhythm and decreased proportionally to increasing numbers of arrhythmia recurrences (p < 0.001 and p = 0.007, respectively). The enlarged left atrial end-systolic diameter at the arrhythmia onset (p = 0.04) and elevated systolic pulmonary artery pressure at 4 h (p = 0.007) were weak predictors of multiple(˃3) recurrences.

CONCLUSION

The LA_EF and Avti are related to arrhythmia recurrences post-cardioversion suggesting potential guidance to the choice between rhythm and rate control strategies.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03029169, registered on 24th of January 2017.

Ischemic stroke and the emerging role of left atrial function

INTRODUCTION

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Emerging evidence suggests that left atrial (LA) dysfunction could play a role in the pathophysiology of ischemic stroke, as a possible contributor and as a predictive biomarker.

AREAS COVERED

This narrative review details the intricate relationship between LA function, atrial fibrillation (AF), and ischemic stroke. We discuss imaging techniques used to assess LA function, the mechanisms by which impaired LA function may contribute to stroke, and its potential as a prognostic marker of stroke.

EXPERT OPINION

There is a lack of evidence-based treatments of LA dysfunction in both primary and secondary stroke prevention. This is partly due to the lack of a practical clinical definition and unanswered questions concerning the clinical implications of LA dysfunction in patients without AF. Until such questions are resolved, addressing well-known cardiovascular risk factors, like hypertension and obesity, should be prioritized for preventing AF and ischemic stroke. These risk factors are closely tied to atrial remodeling, emphasizing the importance of targeting primary modifiable factors for preventing future morbidity and mortality.

Differential Stroke Volume between Left and Right Ventricles as a Predictor of Clinical Outcomes: The MESA Study

Background Valvular heart disease and intracardiac shunts can disrupt the balance between left ventricular (LV) and right ventricular (RV) stroke volumes. However, the prognostic value of such imbalances has not been established among asymptomatic individuals. Purpose To assess the association between differential ventricular stroke volumes quantified using cardiac MRI and clinical outcomes in individuals without cardiovascular disease. Materials and Methods This secondary analysis of a prospective study included participants without cardiovascular disease at enrollment (July 2000 to July 2002) who underwent cardiac MRI. Differences in stroke volume were calculated as LV stroke volume minus RV stroke volume, and participants were categorized as having balanced (greater than or equal to -30 mL to ≤30 mL), negative (less than -30 mL), or positive (>30 mL) differential stroke volumes. Multivariable Cox proportional hazard regression models were used to test the association between differences in stroke volume and adverse outcomes. Results A cohort of 4058 participants (mean age, 61.4 years ± 10 [SD]; 2120 female) were included and followed up for a median of 18.4 years (IQR, 18.3-18.5 years). During follow-up, 1006 participants died, 235 participants developed heart failure, and 764 participants developed atrial fibrillation. Compared with participants who had a balanced differential stroke volume, those with an increased differential stroke volume showed a higher risk of mortality (hazard ratio [HR], 1.73 [95% CI: 1.12, 2.67]; P = .01), heart failure (HR, 2.40 [95% CI: 1.11, 5.20]; P = .03), and atrial fibrillation (HR, 1.89 [95% CI: 1.16, 3.08]; P = .01) in adjusted models. Participants in the negative group, with a decreased differential stroke volume, showed an increased risk of heart failure compared with those in the balanced group (HR, 2.09 [95% CI: 1.09, 3.99]; P = .03); however, this was no longer observed after adjusting for baseline LV function (P = .34). Conclusion Participants without cardiovascular disease at the time of study enrollment who had an LV stroke volume exceeding the RV stroke volume by greater than 30 mL had an increased risk of mortality, heart failure, and atrial fibrillation compared with those with balanced stroke volumes. ClinicalTrials.gov Identifier: NCT00005487 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Almeida in this issue.

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.

Left atrial cardiomyopathy: Pathophysiological insights, assessment methods and clinical implications

Atrial cardiomyopathy is defined as any complex of structural, architectural, contractile or electrophysiological changes affecting atria, with the potential to produce clinically relevant manifestations. Most of our knowledge about the mechanistic aspects of atrial cardiomyopathy is derived from studies investigating animal models of atrial fibrillation and atrial tissue samples obtained from individuals who have a history of atrial fibrillation. Several noninvasive tools have been reported to characterize atrial cardiomyopathy in patients, which may be relevant for predicting the risk of incident atrial fibrillation and its related outcomes, such as stroke. Here, we provide an overview of the pathophysiological mechanisms involved in atrial cardiomyopathy, and discuss the complex interplay of these mechanisms, including aging, left atrial pressure overload, metabolic disorders and genetic factors. We discuss clinical tools currently available to characterize atrial cardiomyopathy, including electrocardiograms, cardiac imaging and serum biomarkers. Finally, we discuss the clinical impact of atrial cardiomyopathy, and its potential role for predicting atrial fibrillation, stroke, heart failure and dementia. Overall, this review aims to highlight the critical need for a clinically relevant definition of atrial cardiomyopathy to improve treatment strategies.

Effect of an intensive lifestyle intervention on the structural and functional substrate for atrial fibrillation in people with metabolic syndrome

AIMS

To evaluate the effect of an intensive lifestyle intervention (ILI) on the structural and functional cardiac substrate of atrial fibrillation (AF) in overweight or obese people with metabolic syndrome (MetS).

METHODS

Participants of the PREDIMED-PLUS trial (n = 6874) were randomised 1:1 to an ILI program based on an energy-reduced Mediterranean diet, increased physical activity, and cognitive-behavioural weight management, or to a control intervention of low-intensity dietary advice. Left atrial (LA) strain, function, and volumes were evaluated by a core echocardiography lab in 534 participants at baseline, 3-year and 5-year follow-up. Mixed models were used to evaluate the effect of the ILI on LA structure and function.

RESULTS

In the subsample, baseline mean age was 65 years (SD 5 years), and 40% of the participants were women. Mean weight change after 5-years was -3.9 kg (SD 5.3 kg) in the ILI group and -0.3 kg (SD 5.1 kg) in the control group. Over the 5-year period, both groups experienced worsening of LA structure and function, with increases in LA volumes and stiffness index and decreases in LA longitudinal strain, LA function index and LA emptying fraction over time. Changes in the ILI and control group were not significantly different for any of the primary outcomes (LA emptying fraction: -0.95% (95%CI -0.93, -0.98) in control group, -0.97% (95%CI -0.94, -1.00) in ILI group, pbetween groups = 0.80; LA longitudinal strain: 0.82% (95%CI 0.79, 0.85) in control group, 0.85% (95%CI 0.82, 0.89) in ILI group, pbetween groups = 0.24) or any of the secondary outcomes.

CONCLUSIONS

In overweight or obese people with MetS, an ILI had no impact on the underlying structural and functional left atrial substrate measurements associated with AF risk.

Impact of rs1805127 and rs55742440 Variants on Atrial Remodeling in Hypertrophic Cardiomyopathy Patients with Atrial Fibrillation: A Romanian Cohort Study

Atrial fibrillation (AFib) is characterized by a complex genetic component. We aimed to investigate the association between variations in genes related to cardiac ion handling and AFib in a cohort of Romanian patients with hypertrophic cardiomyopathy (HCM). Forty-five unrelated probands with HCM were genotyped by targeted next-generation sequencing (NGS) for 24 genes associated with cardiac ion homeostasis. Subsequently, the study cohort was divided into two groups based on the presence (AFib+) or absence (AFiB-) of AFib detected during ECG monitoring. We identified two polymorphisms (rs1805127 located in KCNE1 and rs55742440 located in SCN1B) linked to AFib susceptibility. In AFib+, rs1805127 was associated with increased indexed left atrial (LA) maximal volume (LAVmax) (58.42 ± 21 mL/m2 vs. 32.54 ± 6.47 mL/m2, p < 0.001) and impaired LA strain reservoir (LASr) (13.3 ± 7.5% vs. 24.4 ± 6.8%, p < 0.05) compared to those without respective variants. The rs55742440 allele was less frequent in patients with AFib+ (12 out of 25, 48%) compared to those without arrhythmia (15 out of 20, 75%, p = 0.05). Also, AFib+ rs55742440 carriers had significantly lower LAVmax compared to those who were genotype negative. Among patients with HCM and AFib+, the rs1805127 variant was accompanied by pronounced LA remodeling, whereas rs55742440's presence was related to a milder LA enlargement.

Effect of an intensive lifestyle intervention on the structural and functional substrate for atrial fibrillation in people with metabolic syndrome

Aims

To evaluate the effect of an intensive lifestyle intervention (ILI) on the structural and functional cardiac substrate of atrial fibrillation (AF) in overweight or obese people with metabolic syndrome (MetS).

Methods

Participants of the PREDIMED-PLUS trial (n=6874) were randomised 1:1 to an ILI program based on an energy-reduced Mediterranean diet, increased physical activity, and cognitive-behavioural weight management, or to a control intervention of low-intensity dietary advice. Left atrial (LA) strain, function, and volumes were evaluated by a core echocardiography lab in 534 participants at baseline, 3-year and 5-year follow-up. Mixed models were used to evaluate the effect of the ILI on LA structure and function.

Results

In the subsample, baseline mean age was 65 years (SD 5 years), and 40% of the participants were women. Over the 5-year period, both groups experienced worsening of LA structure and function, with increases in LA volumes and stiffness index and decreases in LA longitudinal strain, LA function index and LA emptying fraction over time. Changes in the ILI and control group were not significantly different for any of the primary outcomes (LA emptying fraction: -0.95% (95%CI -0.93, -0.98) in control group, -0.97% (95%CI -0.94, -1.00) in ILI group, p between groups =0.80; LA longitudinal strain: 0.82% (95%CI 0.79, 0.85) in control group, 0.85% (95%CI 0.82, 0.89) in ILI group, p between groups =0.24) or any of the secondary outcomes.

Conclusions

In overweight or obese people with MetS, an ILI had no impact on the underlying structural and functional left atrial substrate measurements associated with AF risk.

C. Silva T, Ambale-Venkatesh B, Xie E, Ostovaneh MR, Habibi M, Bluemke DA, Soliman EZ, Wu CO, Heckbert SR, Nazarian S, Lima JAC. Association between Left Atrial Late Gadolinium Enhancement and Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA)

Purpose

To determine the prevalence and correlates of left atrial (LA) late gadolinium enhancement (LGE) at cardiac MRI and its association with atrial fibrillation (AF) in a population-based sample from the Multi-Ethnic Study of Atherosclerosis (MESA).

Materials and Methods

In this secondary post hoc analysis of the MESA cohort (ClinicalTrials.gov no. NCT00005487), participants without AF underwent LGE cardiac MRI at the fifth examination (2010-2012). LA LGE burden was quantified using the image intensity ratio technique on biplane long-axis two-dimensional (2D) LGE images without fat saturation. Survival analysis was performed with log-rank testing and Cox regression.

Results

Of 1697 participants (mean age, 67 years ± 9 [SD]; 872 men), 1035 (61%) had LA LGE, and 75 (4.4%) developed AF during follow-up (median, 3.95 years). At univariable analysis, LA LGE was associated with age (β = .010 [95% CI: .005, .015], P < .001), diastolic blood pressure (β = .005 [95% CI: .001, .009], P = .02), HbA1c level (β = .06 [95% CI: .02, .11], P = .009), heart failure (β = .60 [95% CI: .11, 1.08], P = .02), LA volume (β = .008 [95% CI: .004, .012], P < .001), and LA function (emptying fraction, LA global longitudinal strain, LA early diastolic peak longitudinal strain rate, and LA late diastolic peak strain rate; all P < .05). After adjusting for the variables in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) AF score, LA LGE independently helped predict incident AF (hazard ratio = 1.46 [95% CI: 1.13, 1.88], P = .003). The highest tertile (LGE > 2%) was twice as likely to develop AF.

Conclusion

Although limited by the 2D LGE technique employed, LA LGE was associated with adverse atrial remodeling and helped predict AF in a multiethnic population-based sample.Clinical trial registration no. NCT00005487Keywords: MR Imaging, Cardiac, Epidemiology Supplemental material is available for this article. © RSNA, 2023.

Left Atrial Structural and Functional Response in Kidney Transplant Recipients Treated With Mesenchymal Stromal Cell Therapy and Early Tacrolimus Withdrawal

BACKGROUND

Autologous bone marrow-derived mesenchymal stromal cell (MSC) therapy and withdrawal of calcineurin inhibitors (CNIs) has been shown to improve systemic blood pressure control and left ventricular hypertrophy regression in kidney transplant recipients. In the current subanalysis, we aimed to evaluate the impact of this novel immunosuppressive regimen on the longitudinal changes of left atrial (LA) structure and function after kidney transplantation.

METHODS

Kidney transplant recipients randomized to MSC therapy-infused at weeks 6 and 7 after transplantation, with complete discontinuation at week 8 of tacrolimus (MSC group)-or standard tacrolimus dose (control group) were evaluated with transthoracic echocardiography at weeks 4 and 24 after kidney transplantation. The changes in echocardiographic parameters were compared between the randomization arms using an analysis of covariance model adjusted for baseline variable.

RESULTS

Fifty-four participants (MSC therapy = 27; tacrolimus therapy = 27) were included. There was no significant interaction between the allocated treatment and the changes of indexed maximal LA volume (LAVImax) over the study period. Conversely, between 4 and 24 weeks post-transplantation, an increase in indexed minimal LA volume (LAVImin) was observed in control subjects, while it remained unchanged in the MSC group, leading to a significant difference between groups (P = .021). Additionally, patients treated with MSC therapy showed a benefit in LA function, assessed by a significant interaction between changes in LA emptying fraction and LA reservoir strain and the randomization arm (P = .012 and P = .027, respectively).

CONCLUSIONS

The combination of MSC therapy and CNIs withdrawal prevents progressive LA dilation and dysfunction in the first 6 months after kidney transplantation. LAVImin and LA reservoir strain may be more sensitive markers of LA reverse remodeling, compared with LAVImax.

Impact of Structural Abnormalities in Left Ventricle and Left Atrium on Clinical Outcomes in Heart Failure with Preserved Ejection Fraction

Two key echocardiographic parameters, left ventricular mass index (LVMI) and left atrial volume index (LAVI), are important in assessing structural myocardial changes in heart failure (HF) with preserved ejection fraction (HFpEF). However, the differences in clinical characteristics and outcomes among groups classified by LVMI and LAVI values are unclear.We examined the data of 960 patients with HFpEF hospitalized due to acute decompensated HF from the PURSUIT-HFpEF registry, a prospective, multicenter observational study. Four groups were classified according to the cut-off values of LVMI and LAVI [LVMI = 95 g/m2 (female), 115 g/m2 (male) and LAVI = 34 mL/m2]. Clinical endpoints were the composite of HF readmission and all-cause death. Study endpoints among the 4 groups were evaluated. The composite endpoint occurred in 364 patients (37.9%). Median follow-up duration was 445 days. Kaplan-Meier analysis revealed significant differences in the composite endpoint among the 4 groups (P < 0.001). Cox proportional hazards analysis demonstrated that patients with increased LAVI alone were at significantly higher risk of HF readmission and the composite endpoints than those with increased LVMI alone (P = 0.030 and P = 0.024, respectively). Age, male gender, systolic blood pressure at discharge, atrial fibrillation (AF) hemoglobin, renal function, and LAVI were significant determinants of LVMI and female gender, AF, hemoglobin, and LVMI were significant determinants of LAVI.In HFpEF patients, increased LAVI alone was more strongly associated with HF readmission and the composite of HF readmission and all-cause death than those with increased LVMI alone.

Left atrial strain for predicting recurrence in patients with non-valvular atrial fibrillation after catheter ablation: a single-center two-dimensional speckle tracking retrospective study

Background

Although catheter ablation (CA) is an effective treatment for non-valvular atrial fibrillation (AF), a good many of patients still have a recurrence following post-operation. Prediction of AF recurrence by evaluating left atrial (LA) phase function with speckle tracking echocardiography (STE) may be helpful for risk stratification and clinical management for AF patients. Therefore, the current study aimed to assess the prognostic value of LA strains in non-valvular AF patients after CA.

Methods

A total of 95 non-valvular AF patients (70.5% paroxysmal AF, 56.8% males, mean age 63.2 ± 9.7 years) were included in this retrospective study between October 2019 and August 2020. Transthoracic echocardiography was performed in all the subjects and STE was used to analyze the LA reservoir strain (LASr), LA conduit strain (LAScd) and LA contractile strain (LASct) during different phases before CA. Patients were followed up with until January 2022. The endpoint was AF recurrence.

Results

Over a median follow-up period of 26.0 months (interquartile range, 24.7–26.7 months), 26 patients experienced recurrence and 69 stayed in sinus rhythm. Compared with no-recurrence group, maximum volume of LA (LAVmax), minimum volume of LA (LAVmin) and LA volume index (LAVI) were increased in the recurrence group, while LAEF, LASr and LASct were worsened (P < 0.05). Multivariable logistic regression analysis revealed that LASct was an independent predictor of AF recurrence (odds ratio, 0.89; 95% confidence interval (CI), 0.82–0.97; P = 0.007) and receiver operating characteristic (ROC) curve analysis showed an area under the curve of LASct<8% was 0.70 (95% CI, 0.59–0.79; P = 0.0008).

Conclusions

LASct was of independent predictive value of AF recurrence. LA function assessed by STE may contribute to the risk stratification for AF patients and selection of suitable patients for CA.

Left Atrial Strain and the Risk of Atrial Arrhythmias From Extended Ambulatory Cardiac Monitoring: MESA

Background Abnormalities in left atrial (LA) function often occur before LA structural changes and clinically identified atrial fibrillation (AF). Little is known about the relationship between LA strain and the risk of subclinical atrial arrhythmias detected from extended ambulatory cardiac monitoring. Methods and Results A total of 1441 participants of MESA (Multi-Ethnic Study of Atherosclerosis) completed speckle-tracking echocardiography and cardiac monitoring during 2016 to 2018 (mean age, 73 years); participants in AF during echocardiography or during the entire cardiac monitoring period were excluded. Absolute values of LA reservoir, booster pump, and conduit strains were measured. We evaluated associations of LA strain with monitor-detected AF, premature atrial contractions, and supraventricular tachycardia. Primary analyses adjusted for demographic variables, blood pressure, diabetes, smoking, and clinical cardiovascular disease. Cardiac monitoring (median, 14 days) detected AF in 3%. Each SD (4.0%) lower (worse) LA booster pump strain was associated with 84% higher risk of monitor-detected AF (95% CI, 30%-162%), 39% higher premature atrial contraction frequency (95% CI, 27%-53%), and 19% higher supraventricular tachycardia frequency (95% CI, 10%-29%). Additional adjustment for NT-proBNP (N-terminal pro-B-type natriuretic peptide), LA volume index, tissue Doppler a' peak velocity, left ventricular ejection fraction, and global longitudinal strain had little impact on associations. Findings were similar for LA reservoir strain and null for LA conduit strain. Conclusions In a multiethnic community-based cohort, impaired LA strain was an important correlate of subclinical atrial arrhythmias, even after adjustment for conventional measures of LA structure and function.

The Predictive Value of the Left Atrial Kinetic Energy for Atrial Fibrillation Recurrence

Background and aim

Determining which patients will experience recurrence of atrial fibrillation (AF) is crucial for treatment modification. This study aimed to investigate the predictive value of left atrial kinetic energy (LAKE) in AF recurrence.

Materials and methods

A total of 120 consecutive patients who achieved sinus rhythm (SR) with electrical direct current cardioversion and met the inclusion criteria were included in the study. Transthoracic echocardiography (TTE) and LAKE values were calculated on the first day after cardioversion. Rhythm control was performed with 12-lead electrocardiography in the first-month follow-up.

Results

While 81 (67.5%) patients were in SR at one month, AF recurrence was detected in 39 (32.5%) patients. In the AF group, AF duration, cardioversion energy, number of diabetic patients, left atrium (LA) diameter, LA pre-mitral A wave volume, LA minimum volume, and pulmonary artery pressure values were significantly higher than in the SR group, while mitral A wave velocity and LAKE values were significantly lower. In multivariate regression analysis, AF duration (OR: 1.54; 95% CI: 1.22 - 1.93; p < 0.001), LA diameter (OR: 1.33; 95% CI: 1.10 - 1.61; p = 0.002), and LAKE (OR: 0.96; 95% CI: 0.94 - 0.99; p = 0.007) were determined to be independent predictors of AF recurrence at one month.

Conclusions

LA diameter, AF duration, and LAKE were found to be significant predictors of AF recurrence after cardioversion.

Determinants of left atrioventricular coupling index: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Recent studies have described a novel left atrioventricular coupling index (LACI), which had a better prognostic value in predicting cardiovascular events than individual left atrial (LA) or left ventricular (LV) variables.

AIMS

To identify determinants of LACI and its 10-year annual change (ΔLACI), measured by cardiac magnetic resonance (CMR), and to better understand the variables governing this left atrioventricular coupling.

METHODS

In the Multi-Ethnic Study of Atherosclerosis, 2112 study participants, free from cardiovascular disease at baseline, had LACI assessed by CMR imaging at baseline (LACI_Baseline; 2000-2002) and 10 years later (2010-2012). The LACI was defined as the ratio of LA to LV end-diastolic volumes. Linear regression analyses were performed to identify independent determinants of LACI_Baseline and ΔLACI.

RESULTS

In the 2112 participants (mean age 58.8±9.1 years; 46.6% male), after adjustment for all covariates, age was independently associated with LACI_Baseline (R²=0.10, slope=0.16) and ΔLACI (R²=0.15, slope=0.008; both P<0.001). African Americans had the highest LACI_Baseline value (18.0±7.7%). Although there was no difference in LACI_Baseline between women and men (P=0.19), ΔLACI was higher in women (1.0±1.1 vs 0.8±1.1%/year; P<0.001). Diabetes and higher body mass index (BMI) were independently associated with LACI_Baseline (both P<0.001). LACI_Baseline was independently associated with LV myocardial fibrosis markers (native T1: R²=0.11, slope=0.09 [P=0.038]; extracellular volume: R²=0.08, slope=0.28 [P=0.035]) and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) concentration (R²=0.10, slope=-1.11; P<0.001), but was not associated with interleukin 6 or high-sensitivity C-reactive protein.

CONCLUSIONS

Age, sex, ethnicity, diabetes and BMI were independent determinants of LACI. LACI was independently associated with myocardial fibrosis markers and NT-proBNP concentration.

Left atrial adaptation in ischemic heart disease: insights from a cardiovascular magnetic resonance study

Left atrium (LA) plays a key role in the overall cardiac performance. However, it remains unclear how LA adapts, in terms of function and volumes, to left ventricular dysfunction in the acute and post-acute phases of myocardial infarction. LA volumes and function were evaluated in patients in the acute phase of ST-segment elevation myocardial infarction (acute-STEMI group) and in the post-acute phase after STEMI (post-acute STEMI group). Ten age and sex-matched healthy controls served as control group. In all subjects LA was assessed by a compressed-sensing cine pulse sequence and by a 3D non-model-based reconstruction. LV infarct size and microvascular obstruction were determined on late-gadolinium-enhancement data and LV myocardial oedema and myocardial haemorrhage were measured on T2-mapping data. Indexed LA maximum and minimum volumes did not differ between the acute (n = 50) and post-acute (n = 47) STEMI groups. LA active emptying fraction (LAAEF) was higher in the acute-STEMI as compared with the post-acute STEMI groups (0.63 ± 0.23 vs 0.37 ± 0.24, p < 0.0001). Conversely, LA passive emptying fraction (LAPEF) was lower in the acute-STEMI compared with post-acute-STEMI (0.34 ± 0.15 vs 0.65 ± 0.15, p < 0.0001) patients. In the acute-STEMI group, LAAEF was positively and LAPEF negatively correlated with LV myocardial tissue damage (r = 0.523 p = 0.0001; r = - 0.451 p = 0.0013). Negative and positive correlations were also found between LAAEF and LAPEF and time after STEMI (r = - 0.559 p = 0.0013 and r = 0.589 p = 0.0006, respectively). LA increases its active contractile function in the acute phase of STEMI to support LV filling. The extent (but not the type) of LV damage determines LA adaptions which normalizes over time.

The Palma Echo Platform: Rationale and Design of an Echocardiography Core Lab

Background

The metabolic syndrome (MetS) is associated with increased cardiovascular morbidity and mortality. Characterization of cardiac structural and functional abnormalities due to the MetS can help recognize individuals who would benefit the most from preventive interventions. Transthoracic echocardiography (TTE) provides an opportunity to identify those abnormalities in a reproducible and cost-efficient manner. In research settings, implementation of protocols for the acquisition and analysis of TTE images are key to ensure validity and reproducibility, thus facilitating answering relevant questions about the association of the MetS with cardiac alterations.

Methods and Results

The Palma Echo Platform (PEP) is a coordinated network that is built up to evaluate the underlying structural and functional cardiac substrate of participants with MetS. Repeated TTE will be used to evaluate 5-year changes in the cardiac structure and function in a group of 565 individuals participating in a randomized trial of a lifestyle intervention for the primary prevention of cardiovascular disease. The echocardiographic studies will be performed at three study sites, and will be centrally evaluated at the PEP core laboratory. Planned analyses will involve evaluating the effect of the lifestyle intervention on cardiac structure and function, and the association of the MetS and its components with changes in cardiac structure and function. Particular emphasis will be placed on evaluating parameters of left atrial structure and function, which have received more limited attention in past investigations. This PEP will be available for future studies addressing comparable questions.

Conclusion

In this article we describe the protocol of a central echocardiography laboratory for the study of functional and structural alterations of the MetS.

Left atrioventricular coupling index in hypertrophic cardiomyopathy and risk of new-onset atrial fibrillation

BACKGROUNDS

This study aimed to investigate the association between left atrioventricular coupling index (LACI) and the occurrence of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM).

METHODS

A total of 373 patients with HCM and no history of AF were evaluated by transthoracic echocardiography. LACI was defined by the ratio of left atrial (LA) end-diastolic volume divided by left ventricular (LV) end-diastolic volume. The cut-off value for LACI (≥40%) to identify LA-LV uncoupling was chosen based on the risk excess of new-onset AF described with a spline curve analysis.

RESULTS

The median LACI was 37.5% (IQR: 24.4-56.7) and LA-LV uncoupling (LACI ≥40%) was observed in 171 (45.8%) patients. During a median follow-up of 11 (IQR 7-15) years, 118 (31.6%) subjects developed new-onset AF. The cumulative event-free survival at 10 years was 53% for patients with LA-LV uncoupling versus 94% for patients without LA-LV uncoupling (p < 0.001). Multivariable Cox regression analyses performed separately for each LA parameter showed an independent association between new-onset AF and LACI (hazard ratio [HR], 1.021; 95% CI, 1.017-1.026), LA maximum volume indexed (HR, 1.028; 95% CI, 1.017-1.039), LA minimum volume indexed (HR, 1.047; 95% CI, 1.037-1.060) and LA emptying fraction (HR, 0.967; 95% CI, 0.959-0.977, all p < 0.001). The inclusion of LACI in the multivariate model provided a larger improvement in the risk stratification for new-onset AF, as compared to conventional LA parameters.

CONCLUSION

In patients with HCM, LACI was more predictive of the occurrence of new-onset AF than conventional LA parameters.

The Relationship between Enhancing Left Atrial Adipose Tissue at CT and Recurrent Atrial Fibrillation

Background The association of epicardial adipose tissue (EAT) and its metabolic activity with atrial fibrillation (AF) is an area of active investigation. Left atrial (LA) enhancing EAT (e-EAT) at cardiac CT may be a noninvasive surrogate marker for the metabolic activity of EAT. Purpose To determine the relationship between LA e-EAT and recurrence after AF ablation. Materials and Methods In a secondary analysis of a prospective registry of consecutive patients (from July 2018 to December 2019) undergoing first AF ablation, total and LA EAT were segmented on preprocedural noncontrast- and contrast-enhanced cardiac CT scans. LA e-EAT volume fraction was defined as the LA EAT volume difference between the noncontrast- and contrast-enhanced scan divided by the total LA EAT volume on the noncontrast-enhanced scan (threshold values, -15 HU to -195 HU). Continuous variables were compared between groups by using the Mann-Whitney U test. Cox proportional hazard models were used to calculate hazard ratios of predictors of 1-year AF recurrence. Results A total of 212 patients (mean age, 64 years; 159 men) who underwent a first AF ablation were included (paroxysmal AF, 64%; persistent AF, 36%). The LA EAT volume was higher in patients with persistent versus paroxysmal AF (50 cm³ [IQR, 37-72] vs 37 [IQR, 27-49]; P < .001), but no difference was found for LA e-EAT (P = .09). After 1 year of follow-up, AF recurrence rate was 77 of 212 (36%). LA e-EAT above the mean (>33%) was associated with a higher risk of AF recurrence (hazard ratio [HR], 2.1; 95% CI: 1.3, 3.3; P < .01). In a multivariable Cox regression analysis, LA e-EAT retained its predictive value when corrected for sex, age, AF phenotype, LA volume index, and LA EAT volume (HR, 1.9; 95% CI: 1.1, 3.1; P = .02). Conclusion Left atrial enhancing epicardial adipose tissue was independently associated with recurrence after atrial fibrillation ablation. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Stojanovska in this issue.

Frequent premature atrial contractions as a signalling marker of atrial cardiomyopathy, incident atrial fibrillation and stroke

Premature atrial contractions are a common cardiac phenomenon. Although previously considered a benign electrocardiographic finding, they have now been associated with a higher risk of incident atrial fibrillation and other adverse outcomes such as stroke and all-cause mortality. Since premature atrial contractions can be associated with these adverse clinical outcomes independently of atrial fibrillation occurrence, different explanations have being proposed. The concept of atrial cardiomyopathy, where atrial fibrillation would be an epiphenomenon outside the causal pathway between premature atrial contractions and stroke has received traction recently. This concept suggests that structural, functional and biochemical changes in the atria lead to arrhythmia occurrence and thromboembolic events. Some consensus about diagnosis and treatment of this condition have been published, but this is based on scarce evidence, highlighting the need for a clear definition of excessive premature atrial contractions and for prospective studies regarding antiarrhythmic therapies, anticoagulation or molecular targets in this group of patients.

Restoring Sinus Rhythm Reverses Cardiac Remodeling and Reduces Valvular Regurgitation in Patients With Atrial Fibrillation

BACKGROUND

Cardiac chamber remodeling in atrial fibrillation (AF) reflects the progression of cardiac rhythm and may affect functional regurgitation.

OBJECTIVES

The purpose of this study was to explore the 3-dimensional echocardiographic variables of cardiac cavity remodeling and the impact on functional regurgitation in patients with AF with/without sinus rhythm restoration at 12 months.

METHODS

A total of 117 consecutive patients hospitalized for AF were examined using serial 3-dimensional transthoracic echocardiography at admission, at 6 months, and at 12 months (337 examinations).

RESULTS

During follow-up, 47 patients with active restoration of sinus rhythm (SR) (through cardioversion and/or ablation) had a decrease in all atrial indexed volumes (Vi), end-systolic (ES) right ventricular (RV) Vi, an increase in end-diastolic (ED) left ventricular Vi, and an improvement in 4-chambers function (P < 0.05). Patients with absence/failure of restoration of SR (n = 39) had an increase in ED left atrial Vi and ED/ES RV Vi without modification of 4-chambers function, except for a decrease in left atrial emptying fraction (P < 0.05). Patients with spontaneous restoration of SR (n = 31) had no changes in Vi or function. The authors found an improvement vs baseline in severity of functional regurgitation in patients with active restoration of SR (tricuspid and mitral regurgitation) and in spontaneous restoration of SR (tricuspid regurgitation) (P < 0.05). In multivariable analysis, right atrial and/or left atrial reverse remodeling exclusively correlated with intervention (cardioversion and/or ablation) during 12-month follow-up.

CONCLUSIONS

Management of AF should focus on restoration of SR to induce anatomical (all atrial Vi, ES RV Vi) and/or functional (4 chambers) cardiac cavity reverse remodeling and reduce severity of functional regurgitation. (Thromboembolic and Bleeding Risk Stratification in Patients With Non-valvular Atrial Fibrillation [FASTRHAC]; NCT02741349).

Change in Left Atrioventricular Coupling Index to Predict Incident Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background Left atrial (LA) and left ventricular (LV) structural and functional parameters have independent prognostic values as predictors of atrial fibrillation (AF). Purpose To investigate the prognostic value of a left atrioventricular coupling index (LACI) and average annualized change in LACI (hereafter, ΔLACI) measured by cardiac MRI to predict incident AF in a population-based sample from the Multi-Ethnic Study of Atherosclerosis (MESA). Materials and Methods In a secondary analysis of the prospective MESA, 1911 study participants without clinically recognized AF and cardiovascular disease at baseline had LACI assessed with cardiac MRI at baseline (examination 1, 2000-2002) and 10 years later (examination 5, 2010-2012). LACI was defined as the ratio of LA to LV end-diastolic volumes. Univariable and multivariable Cox proportional hazard models were used to evaluate the associations of LACI and average ΔLACI with incident AF. Results Among the 1911 participants (mean age, 59 years ± 9 [standard deviation]; 907 men), 87 incident AF events occurred over 3.9 years ± 0.9 after the second imaging (examination 5). After adjustment for traditional risk factors, greater LACI and ΔLACI were independently associated with AF (hazard ratio, 1.69 [95% CI: 1.46, 1.96] and 1.71 [95% CI: 1.50, 1.94], respectively; both P < .001). Adjusted models for LACI and ΔLACI showed improvement in model discrimination compared with currently used AF risk score (Cohort for Heart and Aging Research in Genomic Epidemiology-Atrial Fibrillation, or CHARGE-AF, score) model (area under receiver operating characteristic curve [AUC], 0.78 vs 0.74; and AUC, 0.80 vs 0.74, respectively; both P < .001); and to the final model including individual LA or LV parameters for predicting AF incidence (AUC, 0.78 vs 0.76; and AUC, 0.80 vs 0.78, respectively; both P < .001). Conclusion Atrioventricular coupling (left atrioventricular coupling index [LACI]) and coupling change (annual change in LACI) were strong predictors for atrial fibrillation (AF) in a multiethnic population. Both had incremental prognostic value for predicting AF over traditional risk factors, and superior discrimination compared with the Cohort for Heart and Aging Research in Genomic Epidemiology-Atrial Fibrillation, or CHARGE-AF, score and to individual left atrial or left ventricular parameters. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Leiner in this issue.

Identifying patients with atrial fibrillation during sinus rhythm on ECG: Significance of the labeling in the artificial intelligence algorithm

•

High performance of AI algorithm to detect AF using SR-ECG was confirmed in patients without structural heart disease.

•

The performance of AI-enabled ECG to detect AF was high especially when the algorithm included SR-ECG taken after the index AF-ECG.

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A similar tendency was observed when the performance was tested in patients with structural heart diseases.

Background

This study aimed to increase the knowledge on how to enhance the performance of artificial intelligence (AI)-enabled electrocardiography (ECG) to detect atrial fibrillation (AF) on sinus rhythm ECG (SR-ECG).

Methods

It is a retrospective analysis of a single-center, prospective cohort study (Shinken Database). We developed AI-enabled ECG using SR-ECG to predict AF with a convolutional neural network (CNN). Among new patients in our hospital (n = 19,170), 276 AF label (having ECG on AF [AF-ECG] in the ECG database) and 1896 SR label with following three conditions were identified in the derivation dataset: (1) without structural heart disease, (2) in AF label, SR-ECG was taken within 31 days from AF-ECG, and (3) in SR label, follow-up ≥ 1,095 days. Three patterns of AF label were analyzed by timing of SR-ECG to AF-ECG (before/after/before-or-after, CNN algorithm 1 to 3). The outcome measurement was area under the curve (AUC), sensitivity, specificity, accuracy, and F1 score. As an extra-testing dataset, the performance of AI-enabled ECG was tested in patients with structural heart disease.

Results

The AUC of AI-enabled ECG with CNN algorithm 1, 2, and 3 in the derivation dataset was 0.83, 0.88, and 0.86, respectively; when tested in patients with structural heart disease, 0.75, 0.81, and 0.78, respectively.

Conclusion

We confirmed high performance of AI-enabled ECG to detect AF on SR-ECG in patients without structural heart disease. The performance enhanced especially when SR-ECG after index AF-ECG was included in the algorithm, which was consistent in patients with structural heart disease.

Left Atrioventricular Coupling Index to Predict Incident Heart Failure: The Multi-Ethnic Study of Atherosclerosis

Background: Although left atrial (LA) and left ventricular (LV) structural and functional parameters have independent prognostic value as predictors of heart failure (HF), the close physiological relationship between the LA and LV suggest that the assessment of LA/LV coupling could better reflect left atrioventricular dysfunction and be a better predictor of HF. Aim: We investigated the prognostic value of a left atrioventricular coupling index (LACI), measured by cardiovascular magnetic resonance (CMR), as well as change in LACI to predict incident HF in the Multi-Ethnic Study of Atherosclerosis (MESA). Materials and Methods: In the MESA, 2,250 study participants, free of clinically recognized HF and cardiovascular disease (CVD) at baseline, had LACI assessed by CMR imaging at baseline (Exam 1, 2000-2002), and 10 years later (Exam 5, 2010-2012). Left atrioventricular coupling index was defined as the ratio of LA to LV end-diastolic volumes. Univariable and multivariable Cox proportional hazard models were used to evaluate the associations of LACI and average annualized change in LACI (ΔLACI) with incident HF after adjustment for traditional MESA-HF risk factors. The incremental risk prediction was calculated using C-statistic, categorical net reclassification index (NRI) and integrative discrimination index (IDI). Results: Among the 2,250 participants (mean age 59.3 ± 9.3 years and 47.6% male participants), 50 incident HF events occurred over 6.8 ± 1.3 years after the second CMR exam. After adjustment, greater LACI and ΔLACI were independently associated with HF (adjusted HR 1.44, 95% CI [1.25-1.66] and adjusted HR 1.55, 95% CI [1.30-1.85], respectively; both p < 0.0001). Adjusted models for LACI showed significant improvement in model discrimination and reclassification compared to currently used HF risk score model for predicting HF incidence (C-statistic: 0.81 vs. 0.77; NRI = 0.411; IDI = 0.043). After adjustment, ΔLACI showed also significant improvement in model discrimination compared to the multivariable model with traditional MESA-HF risk factors for predicting incident HF (C-statistic: 0.82 vs. 0.77; NRI = 0.491; IDI = 0.058). Conclusions: In a multi-ethnic population, atrioventricular coupling (LACI), and coupling change (ΔLACI) are independently associated with incident HF. Both have incremental prognostic value for predicting HF events over traditional HF risk factors.

Changes in left atrial structure and function over a decade in the general population

AIMS

Assessing left atrial (LA) size and function is an important part of the echocardiographic examination. We sought to assess how LA size and function develop over time, and which clinical characteristics promote atrial remodelling.

METHODS AND RESULTS

We examined longitudinal changes of the LA between two visits in the Copenhagen City Heart Study (n = 1065). The median time between the examinations was 10.4 years. LA measurements included: maximal LA volume (LAVmax), minimal LA volume (LAVmin), and LA emptying fraction (LAEF). Clinical and echocardiographic accelerators were determined from linear regression. The value of LA remodelling for predicting incident atrial fibrillation (AF) and heart failure (HF) was examined by Cox proportional hazards regressions. During follow-up, LAVmax and LAVmin significantly increased by 8.3 and 3.5 mL/m2, respectively. LAEF did not change. Age and AF were the most impactful clinical accelerators of LA remodelling with standardized beta-coefficients of 0.17 and 0.28 for changes in LAVmax, and 0.18 and 0.38 for changes in LAVmin, respectively. Left ventricular (LV) systolic function, diameter, and mass were also significant accelerators of LA remodelling. Changes in both LAVmax and LAVmin were significantly associated with incident AF [n = 46, ΔLAVmax: HR = 1.06 (1.03-1.09), P < 0.001 and ΔLAVmin: HR = 1.14 (1.10-1.18), P < 0.001, per 1 mL/m2 increase] and HF [n = 27, ΔLAVmax: HR = 1.08 (1.04-1.12), P < 0.001 and ΔLAVmin: HR = 1.13 (1.09-1.18), P < 0.001, per 1 mL/m2 increase].

CONCLUSION

Both maximal and minimal LA volume increase over time. Clinical accelerators included age and AF. LV structure and systolic function also accelerate LA remodelling. LA remodelling poses an increased risk of clinical outcomes.

Left atrial remodelling, mid-regional pro-atrial natriuretic peptide, and prognosis across a range of ejection fractions in heart failure

AIMS

Measures of structural and functional remodelling of the left atrium (LA) are emerging as useful biomarkers in heart failure (HF). We hypothesized that LA volume and its contribution to stroke volume (SV) would predict a composite endpoint of HF hospitalization or death in patients with HF.

METHODS AND RESULTS

We recruited 57 controls and 86 patients with HF, including preserved and reduced left ventricular ejection fraction (LVEF). Cardiac magnetic resonance imaging was used to evaluate LA volumes and contribution to LV SV. Plasma mid-region pro-atrial natriuretic peptide (MR-proANP) was evaluated. LA volume was negatively correlated with LVEF (P = 0.001) and positively correlated with LV mass in HFrEF (P < 0.001) but not in HFpEF. LA volume at end-diastole was associated with the composite endpoint in HFrEF (hazard ratio 1.26, 95% confidence interval 1.01-1.54; P = 0.044), but not HFpEF (1.06, 0.85-1.30; P = 0.612), per 10 mL/m increase. Active contribution to SV was negatively associated with the composite endpoint in HFpEF (0.32, 0.14-0.66; P = 0.001), but not HFrEF (0.91, 0.38-2.1; P = 0.828) per 10% increase. MR-proANP was associated with the composite endpoint in HFpEF (1.46, 1.03-1.94; P = 0.034), but not in HFrEF (1.14, 0.88-1.37; P = 0.278), per 100 pM increase.

CONCLUSION

We found different relationships between LA remodelling and biomarkers in HFrEF and HFpEF. Our results support the hypothesis that the pathophysiologic underpinnings of HFpEF and HFrEF are different, and atrial remodelling encompasses distinct components for each HF subtype.

Prediction of AF in Heart Failure With Preserved Ejection Fraction: Incremental Value of Left Atrial Strain

OBJECTIVES

This study sought to identify the factors associated with incident atrial fibrillation (AF) in a well-characterized heart failure with preserved ejection fraction (HFpEF) population, with special focus on left atrial (LA) strain.

BACKGROUND

AF is associated with HFpEF, with adverse consequences. Effective risk evaluation might allow the initiation of protective strategies.

METHODS

Clinical evaluation and echocardiography, including measurements of peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA volume index (LAVI), were obtained in 170 patients with symptomatic HFpEF (mean age, 65 ± 8 years), free of baseline AF. AF was identified by standard 12-lead electrocardiogram, review of relevant medical records (including Holter documentation), and surveillance with a portable single-lead electrocardiogram device over 2 weeks. Results were validated in the 103 patients with HFpEF from the Karolinska-Rennes (KaRen) study.

RESULTS

Over a median follow-up of 49 months, incident AF was identified in 39 patients (23%). Patients who developed AF were older; had higher clinical risk scores, brain natriuretic peptide, creatinine, LAVI, and LV mass; lower LA strain and exercise capacity; and more impaired LV diastolic function. PACS, PALS, and LAVI were the most predictive parameters for AF (area under receiver-operating characteristic curve: 0.76 for PACS, 0.71 for PALS, and 0.72 for LAVI). Nested Cox regression models showed that the predictive value of PACS and PALS was independent from and incremental to clinical data, LAVI, and E/e' ratio. Classification and regression trees analysis identified PACS ≤12.7%, PALS ≤29.4%, and LAVI >34.3 ml/m² as discriminatory nodes for AF, with a 33-fold greater hazard of AF (p < 0.001) in patients categorized as high risk. The classification and regression trees algorithm discriminated high and low AF risk in the validation cohort.

CONCLUSIONS

PACS and PALS provide incremental predictive information about incident AF in HFpEF. The inclusion of these LA strain components to the diagnostic algorithm may help guide screening and further monitoring for AF risk in this population.

Association of Left Atrial Metrics with Atrial Fibrillation Rehospitalization and Adverse Cardiovascular Outcomes in Patients with Nonvalvular Atrial Fibrillation following Index Hospitalization

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, with significant clinical and economic burdens, largely driven by adverse cardiovascular outcomes and AF-related hospitalization. Left atrial (LA) parameters have been shown to have prognostic value in cardiovascular disease states. We sought to evaluate the prognostic value of measures of LA size and function, as measured through LA volume index and LA emptying fraction (LAEF), respectively, for AF rehospitalization and long-term adverse outcomes in patients with nonvalvular AF following index hospitalization.

METHODS

In this retrospective study, 594 consecutive patients (mean age, 67.8 ± 13.6 years, 53% men) admitted to a tertiary referral center with nonvalvular AF were assessed. Patients who underwent transthoracic echocardiography during their index admission and had complete follow-up data were included and followed for a mean period of 33.18 ± 21.27 months for the primary outcome of AF rehospitalization. The secondary outcome was a composite of all-cause death and major adverse cardiovascular events.

RESULTS

The primary outcome occurred in 250 (42%) patients, and the secondary outcome occurred in 219 (37%) patients. On multivariable regression analysis, LAEF had an independent association with AF rehospitalization (hazard ratio [HR] = 0.967; 95% CI, 0.953-0.982; P < .01), and time-dependent receiver operating characteristic curves demonstrated LAEF to have strong diagnostic accuracy in predicting early and intermediate AF rehospitalization. Both LA volume index (HR = 1.014; 95% CI, 1.003-1.026; P = .01) and LAEF (HR = 0.982; 95% CI, 0.970-0.993; P < .01) were associated with all-cause death and major adverse cardiovascular events.

CONCLUSIONS

Adverse LA remodeling, as reflected through LA enlargement and reduced LA mechanical function, is associated with AF rehospitalization and long-term adverse cardiovascular outcomes in hospitalized patients with nonvalvular AF.

Subclinical left atrial dysfunction profiles for prediction of cardiac outcome in the general population

OBJECTIVE

Echocardiographic definitions of subclinical left atrial dysfunction based on epidemiological data remain scarce. In this population study, we derived outcome-driven thresholds for echocardiographic left atrial function parameters discriminating between normal and abnormal values.

METHODS

In 1306 individuals (mean age, 50.7 years; 51.6% women), we echocardiographically assessed left atrial function and LV global longitudinal strain. We derived cut-off values for left atrial emptying fraction (LAEF), left atrial function index (LAFI) and left atrial reservoir strain (LARS) to define left atrial dysfunction using receiver-operating curve threshold analysis. Main outcome was the incidence of cardiac events and atrial fibrillation (AFib) on average 8.5 years later.

RESULTS

For prediction of new-onset AFib, left atrial cut-offs yielding the best balance between sensitivity and specificity (highest Youden index) were: LAEF less than 55%, LAFI less than 40.5 and LARS less than 23%. Applying these cut-offs, abnormal LAEF, LAFI and LARS were, respectively, present in 27, 37.1 and 18.1% of the cohort. Abnormal LARS (<23%) was independently associated with higher risk for cardiac events and new-onset AFib (P ≤ 0.012). Participants with both abnormal LAEF and LARS presented a significantly higher risk to develop cardiac events (hazard ratio: 2.10; P = 0.014) and AFib (hazard ratio: 6.45; P = 0.0036) than normal counterparts. The concomitant presence of an impaired LARS and LV global longitudinal strain improved prognostic accuracy beyond a clinical risk model for cardiac events and the CHARGE-AF Risk Score for AFib.

CONCLUSION

Left atrial dysfunction based on outcome-driven thresholds predicted cardiac events and AFib independent of conventional risk factors. Screening for subclinical left atrial and LV systolic dysfunction may enhance cardiac disease prediction in the community.

Association of arterial stiffness with incident atrial fibrillation: a cohort study

Background

Stiff arteries increase left ventricular (LV) end-systolic workload, leading over time to left atrial and ventricular remodeling, and providing the substrate for atrial fibrillation (AF) development. We investigated if carotid femoral pulse wave velocity (cfPWV), a measure of central arterial stiffness, is associated with incident AF.

Methods

In 20112013, cfPWV was measured in 3882 participants of the Atherosclerosis Risk in Communities Cohort Study (ARIC) without prevalent AF. Participants were followed through 2017 for the incidence of AF. Individuals were categorized in cfPWV quartiles based on visit measurements. Multivariable Cox regression models were used to evaluate the association of cfPWV with incident AF.

Results

Mean age was 75years (SD 5), 60% were female and 20% were African American. Over a median follow-up of 5.5years we identified 331 incident cases of AF. cfPWV demonstrated U-shaped associations with AF risk. In models adjusted for age, race, center, sex, education levels, and hemodynamic and clinical factors, hazard ratios (HR) of AF for participants in the first, third and fourth quartiles were 1.49 (95% CI 1.06, 2.10), 1.59 (1.14, 2.10), and 1.56(1.10, 2.19), respectively, compared to those in the second quartile.

Conclusion

Among community-dwelling older adults, low and high central arterial stiffness is associated with AF risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02057-8.

Atrial fibrosis and substrate based characterization in atrial fibrillation: Time to move forwards

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia in clinical practice. However, current therapeutic interventions for atrial fibrillation have limited clinical efficacy as a consequence of major knowledge gaps in the mechanisms sustaining atrial fibrillation. From a mechanistic perspective, there is increasing evidence that atrial fibrosis plays a central role in the maintenance and perpetuation of atrial fibrillation. Electrophysiologically, atrial fibrosis results in alterations in conduction velocity, cellular refractoriness, and produces conduction block promoting meandering, unstable wavelets and micro-reentrant circuits. Clinically, atrial fibrosis has also linked to poor clinical outcomes including AF-related thromboembolic complications and arrhythmia recurrences post catheter ablation. In this article, we review the pathophysiology behind the formation of fibrosis as AF progresses, the role of fibrosis in arrhythmogenesis, surrogate markers for detection of fibrosis using cardiac magnetic resonance imaging, echocardiography and electroanatomic mapping, along with their respective limitations. We then proceed to review the current evidence behind therapeutic interventions targeting atrial fibrosis, including drugs and substrate-based catheter ablation therapies followed by the potential future use of electro phenotyping for AF characterization to overcome the limitations of contemporary substrate-based methodologies.

Altered left atrial 4D flow characteristics in patients with paroxysmal atrial fibrillation in the absence of apparent remodeling

The pathophysiology behind thrombus formation in paroxysmal atrial fibrillation (AF) patients is very complex. This can be due to left atrial (LA) flow changes, remodeling, or both. We investigated differences for cardiovascular magnetic resonance (CMR)-derived LA 4D flow and remodeling characteristics between paroxysmal AF patients and patients without cardiac disease. In this proof-of-concept study, the 4D flow data were acquired in 10 patients with paroxysmal AF (age = 61 ± 8 years) and 5 age/gender matched controls (age = 56 ± 1 years) during sinus rhythm. The following LA and LA appendage flow parameters were obtained: flow velocity (mean, peak), stasis defined as the relative volume with velocities < 10 cm/s, and kinetic energy (KE). Furthermore, LA global strain values were derived from b-SSFP cine images using dedicated CMR feature-tracking software. Even in sinus rhythm, LA mean and peak flow velocities over the entire cardiac cycle were significantly lower in paroxysmal AF patients compared to controls [(13.1 ± 2.4 cm/s vs. 16.7 ± 2.1 cm/s, p = 0.01) and (19.3 ± 4.7 cm/s vs. 26.8 ± 5.5 cm/s, p = 0.02), respectively]. Moreover, paroxysmal AF patients expressed more stasis of blood than controls both in the LA (43.2 ± 10.8% vs. 27.8 ± 7.9%, p = 0.01) and in the LA appendage (73.3 ± 5.7% vs. 52.8 ± 16.2%, p = 0.04). With respect to energetics, paroxysmal AF patients demonstrated lower mean and peak KE values (indexed to maximum LA volume) than controls. No significant differences were observed for LA volume, function, and strain parameters between the groups. Global LA flow dynamics in paroxysmal AF patients appear to be impaired including mean/peak flow velocity, stasis fraction, and KE, partly independent of LA remodeling. This pathophysiological flow pattern may be of clinical value to explain the increased incidence of thromboembolic events in paroxysmal AF patients, in the absence of actual AF or LA remodeling.

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

RATIONALE AND OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Associations of Left Atrial Function and Structure With Supraventricular Ectopy: The Multi-Ethnic Study of Atherosclerosis

Background

High levels of supraventricular ectopy are associated with greater risk of atrial fibrillation, stroke, and death. Little information is available about differences by race/ethnicity in the extent of supraventricular ectopy, or about whether high levels of supraventricular ectopy are associated with impaired left atrial (LA) function and LA enlargement.

Methods and Results

In the MESA (Multi‐Ethnic Study of Atherosclerosis), 1148 participants (47% men; mean age, 67 years) had cardiovascular magnetic resonance imaging in 2010 to 2012, followed by 14‐day ambulatory electrocardiographic monitoring in 2016 to 2018. We analyzed participant characteristics and cardiovascular magnetic resonance measures of LA function and structure in relation to average count of premature atrial contractions (PACs) per hour and average number of runs per day of supraventricular tachycardia. In adjusted regression analyses, older age, male sex, White race, elevated NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), and a history of clinically detected atrial fibrillation were associated with more PACs/hour. Chinese and Hispanic participants had on average fewer PACs/hour than White participants (Chinese participants, 31% less [95% CI, 8%–49%]; Hispanic participants, 38% less [95% CI, 19%–52%]). Greater LA total emptying fraction was associated with fewer PACs/hour (per SD, 16% fewer PACs/hour [95% CI, 7%–25% fewer PACs/hour]). Larger LA minimum volume was associated with more PACs/hour (per SD, 7% more PACs/hour [95% CI, 2%–13% more PACs/hour]). Associations of LA volumes with runs of supraventricular tachycardia/day were similar in direction but were weaker.

Conclusions

Impaired LA function and LA enlargement were associated with more PACs/hour on extended ambulatory electrocardiographic monitoring. Measurement of supraventricular ectopy may provide information about the extent of atrial myopathy.

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

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

Left atrial mechanics for secondary prevention from embolic stroke of undetermined source

Aims 

Anticoagulation is not justified unless atrial fibrillation (AF) is detected in cryptogenic stroke (CS) patients. We sought to explore whether left atrial (LA) remodelling is associated with embolic stroke of undetermined source (ESUS).

Methods and results 

In this prospective study, we evaluated consecutively 186 patients in sinus rhythm who presented with an acute ischaemic stroke (embolic and non-embolic) and sex- and age-matched controls. We performed continuous electrocardiogram (ECG) monitoring to capture paroxysmal AF episodes as recommended by the guidelines. After 12 months of follow-up, continuous ECG monitoring was repeated in patients with undetected AF episodes. We quantified LA reservoir and contraction strain (LASr and LASct) by speckle-tracking, LA volumes by 3D echocardiography. Out of 186 patients, 149 were enrolled after comprehensive investigation for the source of ischaemic stroke and divided into other cause (OC) (n = 52) and CS (n = 97) groups. CS patients were also subdivided into AF (n = 39) and ESUS (n = 58) groups. Among CS patients, LA strain predicted AF independently from CHARGE-AF score and LA volume indices. ESUS group, despite no captured AF, had significantly worse LA metrics than OC and control groups. AF group had the worst LA metrics. Moreover, LASr predicted both CS (embolic stroke with and without AF) and ESUS (embolic stroke with no detected AF) independently from LAVImax and CHA2DS2-VASc score. LASr &gt;26% yielded 86% sensitivity, 92% specificity, 92% positive, and 86% negative predictive values for the identification of ESUS (areas under curve: 0.915, P &lt; 0.0001, 95% confidence interval: 0.86–0.97).

Conclusion 

Echocardiographic quantification of LA remodelling has great potential for secondary prevention from ESUS.

Characterization of cardiac mechanics and incident atrial fibrillation in participants of the Cardiovascular Health Study

BACKGROUND. Left atrial (LA) and left ventricular (LV) remodeling are associated with atrial fibrillation (AF). The prospective associations of impairment in cardiac mechanical function, as assessed by speckle-tracking echocardiography, with incident AF are less clear.

METHODS. In the Cardiovascular Health Study, a community-based cohort of older adults, participants free of AF with echocardiograms of adequate quality for speckle tracking were included. We evaluated the associations of indices of cardiac mechanics (LA reservoir strain, LV longitudinal strain, and LV early diastolic strain rate) with incident AF.

RESULTS. Of 4341 participants with strain imaging, participants with lower LA reservoir strain were older, had more cardiometabolic risk factors, and had lower renal function at baseline. Over a median follow-up of 10 years, 497 (11.4%) participants developed AF. Compared with the highest quartile of LA reservoir strain, the lowest quartile of LA reservoir strain was associated with higher risk of AF after covariate adjustment, including LA volume and LV longitudinal strain (Hazard Ratio [HR], 1.80; 95% CI, 1.31–2.45; P < 0.001). The association of LA reservoir strain and AF was stronger in subgroups with higher blood pressure, NT-proBNP, and LA volumes. There were no associations of LV longitudinal strain and LV early diastolic strain rate with incident AF after adjustment for LA reservoir strain.

CONCLUSION. Lower LA reservoir strain was associated with incident AF, independent of LV mechanics, and with stronger associations in high-risk subgroups. These findings suggest that LA mechanical dysfunction precedes the development of AF. Therapies targeting LA mechanical dysfunction may prevent progression to AF.

FUNDING. This research was supported by contracts HHSN268201200036C, HHSN268200800007C, HHSN268201800001C, N01HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, and N01HC85086 and grants KL2TR001424, R01HL107577, U01HL080295, and U01HL130114 from the NIH’s National Center for Advancing Translational Sciences, and National Heart, Lung, and Blood Institute (NHLBI), with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided by R01AG023629 from the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org.

Left atrial reservoir strain was independently associated with higher risk of atrial fibrillation in this community-based cohort of elderly adults.

Pathophysiology of Hypertensive Heart Disease: Beyond Left Ventricular Hypertrophy

PURPOSE OF REVIEW

Given that the life expectancy and the burden of hypertension are projected to increase over the next decade, hypertensive heart disease (HHD) may be expected to play an even more central role in the pathophysiology of cardiovascular disease (CVD). A broader understanding of the features and underlying mechanisms that constitute HHD therefore is of paramount importance.

RECENT FINDINGS

HHD is a condition that arises as a result of elevated blood pressure and constitutes a key underlying mechanism for cardiovascular morbidity and mortality. Historically, studies investigating HHD have primarily focused on left ventricular (LV) hypertrophy (LVH), but it is increasingly apparent that HHD encompasses a range of target-organ damage beyond LVH, including other cardiovascular structural and functional adaptations that may occur separately or concomitantly. HHD is characterized by micro- and macroscopic myocardial alterations, structural phenotypic adaptations, and functional changes that include cardiac fibrosis, and the remodeling of the atria and ventricles and the arterial system. In this review, we summarize the structural and functional alterations in the cardiac and vascular system that constitute HHD and underscore their underlying pathophysiology.