Current and Clinically Relevant Echocardiographic Parameters to Analyze Left Atrial Function

The evaluation of the left atrial (LA) size using the LA volume index (LAVI) is clinically relevant due to its prognostic significance in various conditions. Nonetheless, adding a LA function assessment to the LAVI provides further clinical and prognostic information in different cardiovascular (CV) diseases. The assessment of LA function by echocardiography primarily includes volumetric measurements (LA ejection fraction [LAEF]), tissue Doppler imaging (TDI) (mitral annular late diastolic velocity [a']), and speckle-tracking methods, such as LA longitudinal reservoir strain (LA strain). This review analyzes and discusses the current medical evidence and potential clinical usefulness of these different methods to analyze LA function.

Assessment of left atrial function provides incremental value: the left atrial volumetric/mechanical coupling index in patients with chronic kidney disease

Background

Heart failure is a common cause of adverse cardiovascular outcomes in patients with chronic kidney disease (CKD). Left atrial (LA) characteristics are thought to be involved in the development of heart failure. However, LA assessment is complex. Though a variety of parameters have been defined, there is no single parameter that best defines LA function. Pilot data indicate that left atrial volumetric/mechanical coupling index (LACI) may be useful, but data with CKD are lacking.

Aim

The objective of this study was to define LACI in a cohort of patients with CKD and to assess its value in evaluating LA function and predicting heart failure.

Methods

A cohort of patients with CKD was enrolled at our hospital between 2021 and 2023. Follow-up was performed for heart failure. LACI is a volumetric to mechanical coupling index, calculated as the ratio of the LA volume index to the tissue-Doppler myocardial velocity at atrial contraction. Spearman's rank correlation or Pearson's correlation was used to calculate the correlation between LACI and echocardiographic/hemodynamic variables. Receiver operating characteristic curve (ROC) analysis was utilised to derive the area under the curve (AUC) for LACI, LVGLS, LASr, LASct and LASI for the detection of heart failure. Kaplan-Meier survival curves were employed to compare clinical outcomes based on LACI thresholds. A multivariable logistic regression analysis was employed to assess the relationship between risk factors and elevated LACI. Cox proportional hazards regression was used to identify risk factors for heart failure.

Results

LACI showed a positive correlation with NT-proBNP, CK-MB, LAVI, E/e' and LASI (r = 0.504, 0.536, 0.856, 0.541 and 0.509, p < 0.001); and a negative correlation with LASr (r = -0.509, p < 0.001). On the ROC analysis for the determination of heart failure, the AUC of LACI was comparable to those of LVGLS (0.588 vs. 509, p = 0.464), LASr (0.588 vs. 0.448, p = 0.132), LASct (0.588 vs. 0.566, p = 0.971) and LASI (0.588 vs. 0.570, p = 0.874). The cardiovascular risk factors increased by LACI were age, BMI, diabetes, triglycerides, LA size, LASr, LASI, E/A, E/e' and EF (p < 0.05). During a median follow-up of 16 months (range, 6-28 months), the event-free survival curves demonstrated a higher risk of heart failure in the group with LACI > 5.0 (log-rank test: P < 0.001). LACI > 5.0 was an independent predictor of heart failure [OR: 0.121, 95% CI (0.020-0.740), p = 0.022].

Conclusion

LACI may prove to be a valuable tool for assessing LA function in patients with CKD, and could be integrated into the routine assessment of LA for the purpose of prognostic assessment and clinical decision-making in patients with CKD.

Associations between neutrophil-lymphocyte ratio and monocyte to high-density lipoprotein ratio with left atrial spontaneous echo contrast or thrombus in patients with non-valvular atrial fibrillation

BACKGROUND

The importance of inflammation in thrombosis is increasingly appreciated. Neutrophil-lymphocyte ratio (NLR) and monocyte to high-density lipoprotein ratio (MHR) are important indicators of systemic inflammation. This study aimed to investigate the associations between NLR and MHR with left atrial appendage thrombus (LAAT) and spontaneous echo contrast (SEC) in patients with non-valvular atrial fibrillation.

METHODS

This retrospective, cross-sectional study enrolled 569 consecutive patients with non-valvular atrial fibrillation. Multivariable logistic regression analysis was used to investigate independent risk factors of LAAT/SEC. Receiver operating characteristic (ROC) curves were used to evaluate the specificity and sensitivity of NLR and MHR in predicting LAAT/SEC. Subgroup and Pearson correlation analyses were used to assess the correlations between NLR and MHR with the CHA₂DS₂-VASc score.

RESULTS

Multivariate logistic regression analysis showed that NLR (OR: 1.49; 95%CI: 1.173-1.892) and MHR (OR: 2.951; 95%CI: 1.045-8.336) were independent risk factors for LAAT/SEC. The area under the ROC curve of NLR (0.639) and MHR (0.626) was similar to that of the CHADS₂ score (0.660) and CHA₂DS₂-VASc score (0.637). Subgroup and Pearson correlation analyses showed significant but very weak associations between NLR (r = 0.139, P < 0.05) and MHR (r = 0.095, P < 0.05) with the CHA₂DS₂-VASc score.

CONCLUSION

Generally, NLR and MHR are independent risk factors for predicting LAAT/SEC in patients with non-valvular atrial fibrillation.

Prognostic Implications of Left Atrial Spontaneous Echo Contrast with Catheter Ablation of Nonvalvular Atrial Fibrillation Patients with Left Atrial Dilation

Background: Left atrial spontaneous echo contrast (LASEC) can be detected by transesophageal echocardiography (TEE) before the catheter ablation of atrial fibrillation (AF), especially in patients with left atrial (LA) dilation. Whether LASEC has prognostic value in predicting the procedure outcomes in patients with an enlarged atrium is unknown. The prognostic implications of LASEC with the catheter ablation of AF patients with LA dilation will be evaluated in this study. Methods: AF patients scheduled to undergo catheter ablation in Ruijin Hospital, Shanghai, China, between January 2018 and June 2020 were screened for this prospective study. All patients underwent TEE before the procedure. Patients with a left atrial diameter (LAD; 45 mm ≤ LAD < 50 mm) and left atrial volume (LAV ≥ 120 mL) were enrolled in this study. The endpoint was AF/atrial tachycardia (AT) recurrence-free survival following a 3-month blanking period after the catheter ablation. All patients were followed up for 18 months. Results: This study included 123 AF patients, who were divided into the LASEC (n = 73) and no LASEC (n = 50) groups. Baseline patient characteristics were similar in the two groups. At the end of 18 months of follow-up, AF/AT recurrence-free survival was achieved in 33 (45.2%) and 34 (68.0%) patients in the LASEC and no LASEC groups, respectively (p = 0.013). In survival analysis, the LASEC group was also associated with a poor outcome of catheter ablation (log-rank test, p = 0.011; Cox regression, p = 0.015, HR = 2.058, 95%CI = 1.151−3.679). Meanwhile, during the follow-up AF/AT recurrence was observed in 30 (57.7%) and 15 (71.4%) cases in the mild and severe SEC groups, respectively. Ischemic stroke occurred in two patients in the LASEC group. Conclusions: LASEC could be a predictor of the recurrence of AF/AT after catheter ablation in AF patients with LA dilation. The higher the degree of LASEC, the worse the prognosis.

The Role of the Left Atrium: From Multimodality Imaging to Clinical Practice: A Review

In recent years, new interest is growing in the left atrium (LA). LA functional analysis and measurement have an essential role in cardiac function evaluation. Left atrial size and function are key elements during the noninvasive analysis of diastolic function in several heart diseases. The LA represents a “neuroendocrine organ” with high sensitivity to the nervous, endocrine, and immune systems. New insights highlight the importance of left atrial structural, contractile, and/or electrophysiological changes, introducing the concept of “atrial cardiomyopathy”, which is closely linked to underlying heart disease, arrhythmias, and conditions such as aging. The diagnostic algorithm for atrial cardiomyopathy should follow a stepwise approach, combining risk factors, clinical characteristics, and imaging. Constant advances in imaging techniques offer superb opportunities for a comprehensive evaluation of LA function, underlying specific mechanisms, and patterns of progression. In this literature review, we aim to suggest a practical, stepwise algorithm with integrative multimodality imaging and a clinical approach for LA geometry and functional analysis. This integrates diastolic flow analysis with LA remodelling by the application of traditional and new diagnostic imaging techniques in several clinical settings such as heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), and mitral regurgitation (MR).

Differences in D-dimer blood concentration in atrial fibrillation patients with left atrial thrombus or severe left atrial spontaneous echo contrast

PURPOSE

Severe left atrial spontaneous echo contrast (SLASEC) is considered the prior stage to thrombosis and a high-risk factor for thrombotic events. Studies have suggested an effect of D-dimer blood concentration on exclusion of left atrial thrombus (LAT), but it remains unclear whether D-dimer concentrations differ between atrial fibrillation (AF) patients with SLASEC or LAT.

METHODS

Nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2017 and July 2020 were screened for this prospective study. All patients underwent transesophageal echocardiography (TEE) to detect SLASEC or LAT. D-dimer concentrations were measured at the time of TEE. Clinical data including CHA₂DS₂-VASc score were evaluated. Major complications with thromboembolism in the SLASEC group were followed up at least 6 months after therapy.

RESULTS

Among 920 consecutively enrolled nonvalvular AF patients, 30 patients with SEC grade 0, 35 patients with SLASEC, and 22 patients with LAT were included. D-dimer concentration and CHA₂DS₂-VASc score were significantly lower in the SLASEC group compared with the LAT group (D-dimer, 0.26±0.13 vs. 0.86±0.9 mg/L, P<0.05; CHA₂DS₂-VASc score, 2.3±0.9 vs. 3.1±1.5, P=0.02). The cut-off value for D-dimer concentration (0.285 mg/L) had sensitivity of 77.3% and specificity of 80.0% for prediction of LAT. D-dimer concentration showed a decreasing trend with a significant difference (0.42±0.22 vs. 0.33±0.18 mg/L, P=0.03) for 9 patients in the LAT group after complete thrombus resolution by anticoagulation treatment. No major or fatal bleeding, ischemic stroke, or systemic thromboembolism events occurred in the SLASEC group during the 6-month follow-up.

CONCLUSIONS

This study demonstrated a significantly lower D-dimer concentration and CHA₂DS₂-VASc score in AF patients with SLASEC than in those with LAT. The D-dimer cut-off value (0.285 mg/L) can be used as an effective reference index to distinguish the pre-thrombotic state of LAT from LAT. D-dimer blood concentration may be a predictor of LAT thrombolysis.

Routine Transesophageal Echocardiography in Atrial Fibrillation Before Electrical Cardioversion to Detect Left Atrial Thrombosis and Echocontrast

BACKGROUND

Transesophageal echocardiography (TEE) before electrical cardioversion (ECV) in atrial fibrillation (AF) is not routinely performed in anticoagulated patients.

METHODS

Starting from TEE findings of anticoagulated and non-anticoagulated patients referred for ECV, we investigated the rate of spontaneous echo-contrast (SEC) and left atrial thrombus (LAT) and identified their independent predictors.

RESULTS

A total of 403 patients were included: 262 (65%) had no anticoagulation, 47 (11.7%) were onnovel oral anticoagulant (rivaroxaban), 74 (18.4%) on warfarin INR>2, and 20 (5.0%) on warfarin INR<2.In 41 (10.1%) there was LAT and in 154 (38.2%) SEC. Patients with LAT had a significantly lower left ventricular ejection fraction (LVEF%) (p=0.001). Patients with SEC were significantly older (p=0.04), had lower LVEF% (p<0.0001),higher CHADSVASC score (p<0.0001), and higher rate of coronary artery disease (CAD) (p=0.03). In 56.8% of warfarin patients (INR>2) there was SEC (p=0.002). At multivariate analysis therapeutic anticoagulation with warfarin (p=0.003; OR:2.2; CI: 1.3-3.7),CHADSVASC score (p<0.0001; OR=1.2; CI: 1.1-1.4), and LVEF% (p<0.0001; OR:0.95; CI: 0.93-0.97; inverse relationship) were SEC predictors. A 3.5 CHADSVASC score cut-off was predictor of SEC (AUC: 0.7; p<0.0001). LVEF% was the only predictor of LAT (p=0.02; OR=0.96; CI: 0.93-0.99; inverse relationship).

CONCLUSIONS

Echocardiography before ECV identifies clear LAT/SEC in more than a third of AF patients, independently by their anticoagulation regimen. LAT/SEC rates increasewith decrement of LVEF%. Increment of CHADSVASC score increases SEC risk. In anticoagulated patients SEC rate remains higher than expected. Therapeutic anticoagulation with Warfarin appears positively and independently correlated to SEC occurrence.

Biomarkers for Predicting Left Atrial or Left Atrial Appendage Thrombus in Anticoagulated Patients with Nonvalvular Atrial Fibrillation

Purpose

Although atrial fibrillation (AF) is often associated with thromboembolic complications, there is no definite biomarker for detecting the presence of thrombi in the left atrial (LA) or left atrial appendage (LAA) in patients with nonvalvular atrial fibrillation (NVAF).

Methods

NVAF patients who underwent transesophageal echocardiography (TEE) to evaluate LA/LAA thrombus and spontaneous echo contrast (SEC) before AF ablation were included. Multivariate logistic regression and receiver operating characteristic curve (ROC) analyses were performed to explore the independent risk factors of LA/LAA thrombus and indicate the best cutoff point.

Results

Of the 260 consecutive subjects (mean age: 63.67 ± 9.39 years; 42% women), 45 (17.3%) patients were with LA/LAA thrombus, 131 (50.4%) were with SEC, and 84 (32.3%) were with neither thrombus nor SEC. The results of multivariate logistic regression analysis showed that N-terminal pro-B-type natriuretic peptide (NT-proBNP) (OR, 2.179; 95% CI: 1.191–3.987; p=0.012) and red cell distribution width (RDW) (OR, 2.398; 95% CI: 1.075–5.349; p=0.033) were independently correlated with the presence of LA/LAA thrombus but not D-dimer (OR, 0.999; 95% CI: 0.998–1.000; p=0.210). When all patients were divided into four groups based on the combination between RDW (cutoff value: 12.95%) and NT-proBNP levels (cutoff value: 368.9 ng/L), the rate of LA/LAA thrombus was the highest in the high RDW and NT-proBNP group.

Conclusion

In anticoagulation patients with NVAF, elevated NT-proBNP and RDW are related to LA/LAA thrombus. Therefore, these might be considered as useful prognostic markers in the management and treatment of NVAF patients.

Atrial premature activity detected after an ischaemic stroke unveils atrial myopathy

BACKGROUND

Recent publications suggest that left atrial (LA) myopathy is a potential source of thromboembolism, independent of atrial fibrillation.

AIMS

We sought to investigate whether the presence of atrial premature activity after an ischaemic stroke is associated with LA remodelling and dysfunction, and might be a surrogate marker of LA myopathy.

METHODS

After an ischaemic stroke or a transient ischaemic attack, patients without known atrial fibrillation or overt heart disease were included prospectively in the study. All patients had a standard workup, including ambulatory Holter electrocardiogram monitoring and transthoracic echocardiography. In some patients, transoesophageal echocardiography was also performed. Anatomical and functional LA remodelling were assessed using minimal and maximal volumes and LA emptying fraction in two-dimensional and three-dimensional echocardiography. Patients were separated into two groups according to the burden of atrial premature complexes (APCs), measured by Holter electrocardiography.

RESULTS

Among 148 eligible patients recruited from October 2015 to May 2016, 93 were included in the group with non-frequent APCs (nf-APC:<100 APCs/24hours) and 43 in the group with frequent APCs (f-APC:>100 APCs/24hours). Twelve patients had paroxysmal atrial fibrillation, and were not included in the statistical analysis. Maximal and minimal indexed LA volumes were significantly higher in the f-APC group than in the nf-APC group (P<0.01). LA emptying fraction was worse in the f-APC group than in the nf-APC group. In addition, LA appendage emptying velocity was impaired in the f-APC group, and was correlated with LA remodelling variables, especially LA emptying fraction (r=0.621).

CONCLUSIONS

After an ischaemic stroke or a transient ischaemic attack, excessive APCs are associated with LA remodelling. Thus, LA dilatation and dysfunction reflect early LA myopathy, which might itself be responsible for cardioembolic stroke.

Left atrial thrombi and spontaneous echo contrast in patients with atrial fibrillation : Systematic analysis of a single-center experience

BACKGROUND

Atrial fibrillation is associated with a high risk for thromboembolic events. Thrombi in the left atrial appendage and spontaneous echo contrast (SEC) correlate positively with this embolic risk. We studied the laboratory, echocardiographic, and epidemiologic parameters that could predict left atrial thrombi and the intensity of the SEC.

PATIENTS AND METHODS

Between September 2013 and June 2015 we included 372 patients with atrial fibrillation before planned electrical cardioversion (transesophageal-guided strategy) in this study. After assessing the risk of stroke and bleeding (CHA₂DS₂-VASc and HAS-BLED scores), we measured the concentration of the D-dimer and B-type natriuretic peptide at the time of the transesophageal echocardiography as well as the left atrial volume and the ejection fraction during transthoracic echocardiography.

RESULTS

The ejection fraction and the CHA₂DS₂-VASc score were identified as independent predictors of both left atrial thrombi and SEC, whereas the left atrial volume could only predict the intensity of SEC. In contrast to the results of other studies, the biomarkers in this study failed to predict the outcome.

CONCLUSION

Only the echocardiographic and epidemiologic parameters were predictors of left atrial thrombi and SEC intensity, while the studied biomarkers had no predictive power. Using clinical data and transthoracic echocardiography, we can change the therapeutic strategy in high-risk patients.

Left Atrial Remodeling Assessed by Transthoracic Echocardiography Predicts Left Atrial Appendage Flow Velocity in Patients With Paroxysmal Atrial Fibrillation

Atrial fibrillation (AF) is associated with an increased risk of stroke and other thromboembolic events. Left atrial (LA) thrombus formation is closely related to LA dysfunction, particularly to decreased LA appendage flow velocity (LAA-FV) in patients with AF. We estimated LAA-FV using parameters noninvasively obtained by transthoracic echocardiography (TTE) in patients with paroxysmal AF.Echocardiographic and clinical parameters were assessed in 190 patients with nonvalvular paroxysmal AF showing sinus heart rhythm during transesophageal echocardiography (TEE) and TTE.LAA-FV (60 ± 22 cm/s) significantly correlated with the time interval between the initiation of the P-wave on ECG and that of the A-wave of transmitral flow on TTE (PA-TMF, correlation coefficient, -0.32; P < 0.001), LA dimension (LAD, -0.31; P < 0.001), septal a' velocity of tissue Doppler imaging (TDI, 0.35; P < 0.001), E/e' ratio (-0.28, P < 0.001), E velocity of transmitral flow (-0.20, P = 0.008), E/A ratio of transmitral flow (-0.18, P = 0.02), CHA2DS2-VASc score (-0.15, P = 0.04), and BNP plasma level (-0.32, P = 0.002). Multivariate analysis revealed that PA-TMF (standardized partial regression coefficient, -0.17; P = 0.03), a' velocity (0.24, P = 0.004), and LAD (-0.20, P = 0.01) were independent predictors of LAA-FV (multiple correlation coefficient R, 0.44; P < 0.001).Parameters of atrial remodeling, ie, decreased a' velocity, increased LAD, and PA-TMF during sinus rhythm may be useful predictors of LA blood stasis in patients with nonvalvular PAF. LAA-FV can be estimated using these TTE parameters instead of TEE.