The Role of Echocardiography in Thromboembolic Risk Assessment of Patients with Nonvalvular Atrial Fibrillation

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

OBJECTIVE

To evaluate left atrial volume and function in patients with paroxysmal atrial fibrillation (AF) combined with left atrial appendage thrombosis and patients with paroxysmal AF without left atrial appendage thrombosis by 3-dimensional speckle tracking imaging (3D-STI), and to explore the application value of this set of parameters in the evaluation of left atrial function in patients with paroxysmal AF.

MATERIALS AND METHODS

A total of 40 patients with paroxysmal AF admitted from December 2018 to December 2020 were selected as the observation group. All patients with paroxysmal AF in the observation group underwent transesophageal echocardiography. According to the presence of left atrial appendage thrombosis, the patients were divided into the AF without thrombosis group (24 cases) and the AF with thrombosis group (16 cases). Thirty normal people were selected as control group who were chosen as having no heart-related disease. The left atrial volume parameters (Left atrial maximum volume LAVmax, Left atrial minimum volume LAVmin, Left atrial volume before atrial contraction LAVpre-A, Left atrial stroke volume LAEV), left atrial ejection fraction (LAEF) and left atrial strain parameters (Left atrial reservoir longitudinal strain LASr, Left atrial conduit longitudinal strain LAScd, Left atrial contraction longitudinal strain LASct, Left atrial reservoir circumferential strain LASr-c, Left atrial conduit circumferential strain LAScd-c, Left atrial contraction circumferential strain LASct-c) of the 3 groups were measured by 3D-STI.

RESULTS

With the progression of paroxysmal AF, the left atrial volume increased, and the reservoir, conduit and contractile function were damaged. The left atrial volume continued to increase, and the reservoir, conduit and contractile function further decreased significantly in patients with AF combined with left atrial appendage thrombosis. LAEF was positively correlated with LASr and LASr_c.

CONCLUSION

Real-time 3-dimensional spot tracking imaging (3D-STI) can evaluate the changes in left atrial volume and function in patients with paroxysmal AF, and has a certain reference value for clinical judgment of disease progression and prognosis.

Efficacy of Low-Dose Isoproterenol Infusion for the Exclusion of a Left Atrial Appendage Thrombus in Patients With Dense Spontaneous Echo Contrast Caused by Atrial Fibrillation

BACKGROUND

In patients with atrial fibrillation (AF) and severe blood stasis in the left atrial appendage (LAA), dense spontaneous echo contrast (SEC) disturbs the distinct visualization of the LAA interior, thus making thrombus diagnosis inconclusive. We aimed to prospectively assess the efficacy and safety of a protocol for a low-dose isoproterenol (ISP) infusion to reduce SEC to exclude an LAA thrombus.Methods and Results: We enrolled 17 patients with AF and dense SEC (Grade 4 or sludge). ISP was infused with gradually increasing doses of 0.01, 0.02, and 0.03 μg/kg/min at 3-min intervals. After increasing the dose to 0.03 μg/kg/min for 3 min, or when the LAA interior was visible, the infusion was terminated. We reassessed the SEC grade, presence of an LAA thrombus, LAA function, and left ventricular ejection fraction (LVEF) within 1 min of ISP termination. Compared with baseline, ISP significantly increased LAA flow velocity, the LAA emptying fraction, LAA wall velocities, and LVEF (all P<0.01). ISP administration significantly reduced the SEC grade (median) from 4 to 1 (P<0.001). The SEC grade decreased to ≤2 in 15 (88%) patients, and the LAA thrombus was excluded. There were no adverse events.

CONCLUSIONS

Low-dose ISP infusion may be effective and safe to reduce SEC and exclude an LAA thrombus by improving LAA function and LVEF.

Evaluation of Left Atrial Function in Patients with Paroxysmal Atrial Fibrillation Using Left Atrial Automatic Myocardial Functional Imaging Ultrasonography

Aim

To evaluate volume and strain of the left atrium (LA) in people suffering from paroxysmal atrial fibrillation which is not valvular (NVPAF) using the new technology of left atrial automatic myocardial function imaging (AFILA) and to analyze prognostic factors in patients with NVPAF by follow-up.

Methods

Between August 2019 and August 2022, a total of 80 NVPAF patients and 60 normal control patients who were hospitalized in the Department of Cardiology were included in the study. The LA volume and strain parameters of the two groups were analyzed. The differences in LA function (LAF) parameters were compared between the two groups to generate the receiver operating characteristic curve (ROC) and calculate the area under the curve (AUC), sensitivity, and specificity of each parameter. Follow-up was conducted on the 80 NVPAF patients included, their treatment methods after admission and their rehospitalization due to heart events were recorded, and independent risk factors influencing the prognosis of NVPAF were obtained.

Results

A total of 140 patients participated in the study, including 80 in the NVPAF group and 60 in the normal control group. There was no statistically significant difference in age and sex between the two groups. Compared to the normal group, the LA minimum volume (LAVmin), LA maximum volume (LAVmax), and volume at onset of LA contraction (LAVpreA) in the NVPAF group were significantly increased. The LA emptying fraction (LAEF) was significantly decreased, and LA reservoir strain (S_R), LA conduit strain (S_CD), and LA contractile strain (S_CT) were significantly compromised (P < 0.05). There was no significant difference in LA evacuation volume (LAEV) reduction (P > 0.05). Logistic regression analysis of LAF parameters in NVPAF patients showed that LAEF and S_R were independently correlated with NVPAF (odds ratio values: 0.883 (0.827-0.943), P < 0.001; 0.916 (0.569-1.474), P = 0.047). The ROC curve results showed that LAEF had a high efficiency in the diagnosis of NVPAF, with P < 0.001, AUC of 0.843, sensitivity of 0.788, and specificity of 0.867. For the LA strain parameters, the S_R test efficiency was higher, with P < 0.001, AUC of 0.762, sensitivity of 0.713, and specificity of 0.783. There was a strong correlation between S_R and LAEF in patients with no end event and those with end event. The ROC curve revealed that the S_R was better than LAEF in predicting prognosis of patients with AF (AUC = 0.914, P < 0.0001 vs. AUC = 0.876, P < 0.0001). S_R of 10.5 and LAEF of 21 were the cut-off values for endpoint events in NVPAF patients, with sensitivity of 0.909 and 0.727 and specificity of 0.904 and 0.901, respectively.

Conclusions

AFILA ultrasound technology comprehensively evaluated the LA size and function in patients with NVPAF. The LAEF and S_R were independently correlated with NVPAF and can determine the prognosis of patients with NVPAF.

Preprocedural Multimodality Imaging in Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased risk of heart failure, stroke, and death. In current medical practice, multimodality imaging is routinely used in the management of AF. Twenty-one years ago, the ACUTE trial (Assessment of Cardioversion Using Transesophageal Echocardiography) results were published, and the management of AF changed forever by incorporating transesophageal echocardiography guided cardioversion of patients in AF for the first time. Current applications of multimodality imaging in AF in 2022 include the use of transesophageal echocardiography and computed tomography before cardioversion to exclude left atrial thrombus and in left atrial appendage occlusion device implantation. Transesophageal echocardiography, cardiac computed tomography, and cardiac magnetic resonance are clinically used for AF ablation planning. The decision to use a particular imaging modality in AF is based on patient's characteristics, guideline recommendation, institutional preferences, expertise, and cost. In this first of 2-part review series, we discuss the preprocedural role of echocardiography, computed tomography, and cardiac magnetic resonance in the AF, with regard to their clinical applications, relevant outcomes data and unmet needs, and highlights future directions in this rapidly evolving field.

The Atrium in Atrial Fibrillation - A Clinical Review on How to Manage Atrial Fibrotic Substrates

Atrial fibrillation (AF) is the most common sustained arrhythmia in the population and is associated with a significant clinical and economic burden. Rigorous assessment of the presence and degree of an atrial arrhythmic substrate is essential for determining treatment options, predicting long-term success after catheter ablation, and as a substrate critical in the pathophysiology of atrial thrombogenesis. Catheter ablation of AF has developed into an essential rhythm-control strategy. Nowadays is one of the most common cardiac ablation procedures performed worldwide, with its success inversely related to the extent of atrial structural disease. Although atrial substrate evaluation remains complex, several diagnostic resources allow for a more comprehensive assessment and quantification of the extent of left atrial structural remodeling and the presence of atrial fibrosis. In this review, we summarize the current knowledge on the pathophysiology, etiology, and electrophysiological aspects of atrial substrates promoting the development of AF. We also describe the risk factors for its development and how to diagnose its presence using imaging, electrocardiograms, and electroanatomic voltage mapping. Finally, we discuss recent data regarding fibrosis biomarkers that could help diagnose atrial fibrotic substrates.

Left atrial strain measured by 4D Auto LAQ echocardiography is significantly correlated with high risk of thromboembolism in patients with non-valvular atrial fibrillation

Background

The 4-dimensional automated left atrial quantification (4D Auto LAQ) tool is a new software for analysis of the structure and function of the left atrium (LA). This study aimed to evaluate the relationship between LA strain (LAS) as measured by 4D Auto LAQ echocardiography and thromboembolism risk in patients with non-valvular atrial fibrillation (NVAF).

Methods

Eight-five patients with NVAF were recruited from the cardiovascular center of our hospital, including 39 patients at high risk and 46 patients at low risk of thromboembolism. The study participants were assessed by routine echocardiography; 4D images were obtained, after which 4D Auto LAQ assessment was performed.

Results

In the thromboembolism high-risk group, the rates of impaired LA reservoir strain, LA contraction strain, LA reservoir circumferential strain, LA conduit circumferential strain, and LA contraction circumferential strain were found to be significantly higher than in the low-risk group. However, there was no significant difference in volume at onset of LA contraction or LA ejection fraction (LAEF) between the 2 groups. LA contraction circumferential strain was found to be an independent high risk factor for thromboembolism [odds ratio (OR): 2.52; P=0.008]. LA contraction circumferential strain >-4.5% was the cut-off for differentiating between participants with high and low risk of thromboembolism, with an area under the curve (AUC) of 0.95 (P<0.0001), a sensitivity of 0.872, and a specificity of 0.978. Sequential analysis revealed that LA contraction circumferential strain had a high diagnostic efficacy for stroke, as well as a specified accuracy in the diagnosis of hypertension and diabetes in patients aged ≥65 years old. However, it was not found to be effective in the diagnosis of heart failure and vascular diseases.

Conclusions

LAS is a useful index for the dynamic evaluation of LA function in patients with non-valvular AF, with higher sensitivity and accuracy than LA volume. LA contraction circumferential strain is an independent high risk factor for thromboembolism, and LA contraction circumferential strain >-4.5% is a valuable cut-off to guide the use of anticoagulant therapy in patients with non-valvular AF.

Incremental diagnostic role of left atrial strain analysis in thrombotic risk assessment of nonvalvular atrial fibrillation patients planned for electrical cardioversion

During the COVID-19 pandemic, transesophageal echocardiography (TEE) for left atrial appendage thrombosis (LAAT) detection should be limited to situations of absolute necessity. We sought to identify the main conventional and functional echocardiographic parameters associated with LAAT on TEE in non-valvular atrial fibrillation (NVAF) patients planned for electrical cardioversion (ECV). This retrospective study included 125 consecutive NVAF patients (71.5±7.8 yrs, 75 males), who underwent TEE at our Institution between April 2016 and January 2020, to exclude LAAT before scheduled ECV. All patients underwent a transthoracic echocardiography (TTE) implemented with speckle tracking echocardiography (STE) analysis of left atrial (LA) strain and strain rate (SR) parameters. 28% of patients were diagnosed with LAAT, while 72% without LAAT. Compared to controls, patients with LAAT had significantly higher CHA₂DS₂-Vasc Score and average E/e’ ratio, and significantly lower left ventricular ejection fraction (LVEF). Moreover, LA-peak positive global atrial strain (GSA+) and LA-SR parameters were significantly reduced in patients with LAAT. Multivariate logistic regression revealed that, differently from CHA₂DS₂-Vasc Score, LVEF (OR 0.88, 95%CI 0.81–0.97, p = 0.01), average E/e’ ratio (OR 2.36, 95%CI 1.41–3.98, p = 0.001), and LA-GSA+ (OR 0.57, 95%CI 0.36-0-90, p = 0.01) were independently associated with LAAT. LA-GSA+ (optimal cut-off ≤ 9.1%, AUC 0.95) showed the highest diagnostic performance. Finally, a strong linear correlation of LA peak-to-peak SR with both LA appendage filling (r = 0.86) and emptying (r = 0.83) velocities was demonstrated. TTE implemented with STE analysis of LA mechanics improves thrombotic risk assessment of NVAF patients.

The role of biomarkers and neuroimaging in ischemic/hemorrhagic risk assessment for cardiovascular/cerebrovascular disease prevention

Stroke prevention in patients with atrial fibrillation is arguably one of the fastest developing areas in preventive medicine. The increasing use of direct oral anticoagulants and nonpharmacologic methods such as left atrial appendage closure for stroke prevention in these patients has increased clinicians' options for optimal care. Platelet antiaggregants are also commonly used in other ischemic cardiovascular and or cerebrovascular conditions. Long term use of oral anticoagulants for atrial fibrillation is associated with elevated risks of major bleeds including especially brain hemorrhages, which are known to have extremely poor outcomes. Neuroimaging and other biomarkers have been validated to stratify brain hemorrhage risk among older adults. A thorough understanding of these biomarkers is essential for selection of appropriate anticoagulant or left atrial appendage closure for stroke prevention in patients with atrial fibrillation. This article will address advances in the stratification of ischemic and hemorrhagic stroke risk among patients with atrial fibrillation and other conditions.

Myocardial performance index by tissue Doppler echocardiography predicts adverse events in patients with atrial fibrillation

AIMS

The prognostic value of myocardial performance index (MPI) has not yet been assessed in patients with atrial fibrillation (AF). The aim of this study was to evaluate the prognostic value of MPI by tissue Doppler imaging (TDI) M-mode in AF patients.

METHODS AND RESULTS

Echocardiograms from 210 patients with AF during examination were analysed offline. Patients with known heart failure (HF) were excluded. Time intervals were measured using an M-mode line through the mitral valve leaflets to provide a colour diagram of the mitral leaflet movement so all time intervals could be measured from one cardiac cycle. MPI was calculated as the sum of isovolumic relaxation time and isovolumic contraction time divided by the ejection time [(IVRT+IVCT)/ET]. During a median follow-up of 2.4 years, 84 patients (40%) reached the combined endpoint of major adverse cardiovascular events (MACE), being all-cause mortality, HF, myocardial infarction, or stroke. Increasing MPI was significantly associated with an increased risk of MACE, and the risk increased with 20% per 0.1 increase in MPI [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.10-1.32; P < 0.001]. Increasing MPI was also significantly associated with a lower left ventricular ejection fraction (LVEF) (P < 0.001). Nevertheless, MPI remained an independent predictor even after adjustment for age, sex, diabetes mellitus, left atrial volume, and LVEF (HR 1.12, 95% CI 1.01-1.25; P = 0.038).

CONCLUSION

Increasing MPI was significantly associated with increased risk of MACE and remained an independent predictor after multivariable adjustment. This demonstrates that the MPI obtained by TDI M-mode might be useful in assessing cardiac function in AF patients with ongoing arrhythmia during examination.

Inverse Correlation Between Left Atrial Appendage Function and CHA2DS2-VASc Score in Patients with Atrial Flutter

Impaired left atrial appendage ejection fraction (LAA-EF) and peak LAA flow velocity (LAA-FV) are associated with high thromboembolic risks in patients with atrial fibrillation (AF). Herein, we examined LAA function among patients with atrial flutter (AFL) stratified by the CHA₂DS₂-VASc score using transesophageal echocardiography (TEE). Of 231 consecutive patients with typical AFL, 84 who fulfilled the inclusion criteria were enrolled. Among them, 57 had ongoing AFL and were divided into the isolated AFL (n = 38) and AFL with paroxysmal AF (PAF) (n = 19) groups, depending on whether they had sporadic AF before TEE. The remaining 27 patients with spontaneous sinus rhythm during TEE were designated as controls. Both the LAA-FV (31.9 cm/s vs. 51.5 cm/s, P = 0.004) and LAA-EF (28.4% vs. 36.5%, P = 0.024) measured during AFL were significantly lower in the AFL + PAF group than in the isolated AFL group. Significant inverse correlations between the CHA₂DS₂-VASc score and LAA-EF were identified in the AFL (P = 0.008) and AFL + PAF (P = 0.032) groups. We observed progressive LAA dysfunction in patients with AFL + PAF compared with that in patients with isolated AFL, and the LAA-EF was inversely correlated with the CHA₂DS₂-VASc score in these patients. Our findings may have implications on the application of thromboprophylactic therapy in patients with AFL.

Two-dimensional Echocardiographic Assessment of Myocardial Strain: Important Echocardiographic Parameter Readily Useful in Clinical Field

Echocardiography is the first and is the most-available imaging modality for many cardiovascular diseases, and echocardiographic parameters can give much important information for diagnosis, treatment, and prognostic evaluations. Left ventricular ejection fraction (LVEF) is the most commonly used echocardiographic parameter for left ventricular (LV) systolic function. Although LVEF is used routinely in daily practice, it is calculated from volumetric change without representing true myocardial properties. Recently, strain echocardiography has been used to objectively measure myocardial deformation. Myocardial strain can give accurate information about intrinsic myocardial function, and it can be used to detect early-stage cardiovascular diseases, monitor myocardial changes with specific therapies, differentiate cardiomyopathies, and predict the prognosis of several cardiovascular diseases. Although strain echocardiography has been applied to measure the right ventricle and left atrium, in addition to analyzing the LV, many cardiologists who are not imaging specialists are unaware of its clinical use and importance. Therefore, this review describes the measurement and clinical utility of 2-dimensional strain analysis in various cardiovascular diseases.

Food-Related Atrial Fibrillation? The Potential Role of Biogenic Amines in “Nutri-Arrhythmias” Genesis

Atrial fibrillation (AF) is the most common type of arrhythmia: a disorganized electrical atrial activity leading to irregular ventricular beats. Its most common risk factors include high blood pressure, congenital and valvular heart diseases, aging, heart failure and coronary heart diseases. Other risk factors include excessive alcohol intake, tobacco smoking, diabetes mellitus and thyrotoxicosis. However, many cases are not associated with any of these risk factors: probably, in these patients, immunological, functional and even dietary mechanisms may be responsible to induce cardiac arrhythmias. Several studies have focused on immunological and neurohumoral mechanisms; however, little information is available about the potential relationship between dietary patterns and atrial fibrillation episodes. This case report describes a potential correlation between biogenic amines in ingested food and recurrent atrial fibrillation onset in a 61-years old man in absence of a remarkable clinical history and of the most common risk factors. The nutritional team instituted a food protocol: a low calories diet and eliminating biogenic amines-rich foods. During the follow-up (16 months), there was a noticeable weight loss and no arrhythmic episodes happened again. This clinical case provides evidence for a possible new relationship between some kinds of food and heart conduction (defining the very novel field of arrhythmogenic foods and of “nutri-arrhythmias”), recognizing biogenic amines-rich foods abuse as the potential trigger and substrate for atrial fibrillation. Therefore, we suggested that clinical history in patients with new onset AF should also include questions concerning the ingestion of histamine-rich foodstuffs (or other amines-rich food) and alcohol consumption: their effects may result to be synergistic in the alteration of cardiac rhythm and may explain the recurrence of an unexplained atrial fibrillation.

How do aging and comorbidities impact risk of ischemic stroke in patients with atrial fibrillation

Stroke is a notorious complication in patients with atrial fibrillation (AF) and risk stratification is pivotal for stroke prevention strategy. The risk of AF-related stroke is a mixture of complex interaction between increasing age and important comorbidities. Therefore, this article aims to provide a comprehensive review on these important risk factors of stroke in AF patients, mainly focusing on the component of CHA₂DS₂-VASc score, as well as some other potential risk factors.

Effect of transcatheter aortic valve replacement on left atrial function

OBJECTIVES

To investigate the effect of transcatheter aortic valve replacement on left atrial volumetric function and left atrial volume for the prediction of adverse outcomes.

METHODS

This is a retrospective analysis of 121 patients in sinus rhythm who underwent TAVR for severe AS. Maximum LA volume index (LAVI max), minimum LA volume index (LAVI min), and "pre-A" volume index (LAVIpre-A, the volume before atrial contraction) were measured by biplane Simpson's method at baseline, 1 month, and 1 year. The reservoir function, conduit function, booster pump function were calculated. All patients were followed for new-onset of atrial fibrillation, hospitalization and all-cause mortality.

RESULTS

The reservoir function, conduit function and booster function before TAVR were 46%, 21%, 32%, respectively. LA volumetric function assessment demonstrated that reservoir function, conduit function increased over the time (all P < 0.01). There was no difference in booster function after TAVR (P = 0.18). Baseline markedly enlarged LA was significantly increased for AF (HR: 4.72; 95% CI, 1.11-20.13, P = 0.04). In addition, There was a progressive decrease in LAVI max (P = 0.02) and RVSP (P = 0.03) over the time in non-AF group but not in AF group (P = 0.62 and P = 0.65, respectively). Although, the proportion of high left ventricular filling pressure decreased in both groups but a marked decrease was noted in non AF group in compared with AF group.

CONCLUSION

Reservoir function, conduit function increased over time. Lack of negative LA remodeling post TAVR was associated with higher incidence of AF.

Relation between left atrial measurements and thromboembolic risk markers assessed by echocardiography in patients with nonvalvular atrial fibrillation: A cross-sectional study

Background

Left atrium (LA) dilatation has been associated with adverse cardiovascular outcomes in patients with sinus rhythm and atrial fibrillation (AF).

Aim of the study

We aimed to evaluate the accuracy of left atrial (LA) size to predict transesophageal echocardiographic (TEE) markers of increased thromboembolic risk left atrial appendage (LAA) thrombus, low LAA velocities and dense spontaneous echocardiographic contrast (SEC), and also to assess the best method to evaluate LA size.

Patients and methods

Cross-sectional study included 64 patients with nonvalvular AF undergoing transthoracic and transesophageal echocardiographic (TTE and TEE) evaluation. LA size was measured on TTE by several methods including the following: anteroposterior diameter (AP), LA area in four and two apical chamber views and volumes by ellipsoid, single plane (1P) and biplane area-length (2P) formulas. All these measures were indexed to the body surface area (BSA). Thromboembolic markers including LAA thrombus, low LAA velocities, dense SEC and LA abnormality (LA ABN) which means the presence of one or more of the previous three parameters were evaluated by TEE.

Results

There was statistically significant increase in indexed and non-indexed LA parameters in patients with LA ABN compared to patients without LA ABN. According to ROC curve, the study found that all indexed LA parameters were predictive for LAA thrombus with the highest AUC was indexed LA 1P area length volume (AUC 0.91, CI 95% 0.81-1.01, p < 0.000), for LAA low flow velocity were indexed and non-indexed LA AP diameters with the highest AUC was indexed LA AP diameter (AUC 0.89, CI 95% 0.80-0.98, p < 0.000), for LA dense SEC were indexed LA ellipsoid volume (AUC 0.78, CI 95% 0.66-0.96, p = 0.002) and indexed LA 1P area length volume (AUC 0.78, CI 95% 0.66-0.90, p = 0.002) and for LA ABN were all LA parameters with the highest AUC was indexed LA 1P area length volume (AUC 0.87, CI 95% 0.79-0.96, p < 0.000). On multivariate logistic regression analysis of TEE parameters, the study found that the most predictive LA measurement for LAA thrombus was indexed LA AP diameter with cutoff 3 cm/m² (OR 7.5, 95% CI 1.24-45.2, p = 0.02), for LAA low flow velocity was LA AP diameter with cutoff 6 cm (OR 17.6, 95% CI 3.23-95.84, p = 0.001), for LA dense SEC was indexed LA ellipsoid volume with cutoff 42 cm³/m² (OR 6.5, 95% CI 1.32-32.07, p = 0.02), and for LA ABN was indexed LA ellipsoid volume with cutoff 42 cm³/m² (OR 10.45, 95% CI 2.18-51.9, p = 0.008).

Conclusion

LA enlargement is suitable to predict thromboembolic markers in patients with non-valvular AF. The indexed and non-indexed LA AP diameter and indexed LA ellipsoid volume were the most accurate parameters for predicting thromboembolic markers.

Left Atrial Strain Predicts Pro-Thrombotic State in Patients with Non-Valvular Atrial Fibrillation

Background and Purpose

Atrial fibrillation (AF) has a high prevalence in the population and it is responsible for up to the 25% of the strokes in elderly people. The aim of our study was to assess the correlations of left atrial (LA) functional parameter, global peak atrial longitudinal strain (PALS), derived from speckle tracking echocardiography (STE), with transesophageal echocardiography (TEE) findings in patients with persistent AF undergoing TEE before electrical cardioversion or ablation procedures.

Methods

79 patients (58 males, 21 females) with persistent AF waiting for cardioversion were included in the study. The patients underwent conventional two-dimensional (2D) and 2D speckle tracking echocardiogram. PALS were measured in all subjects. Patients were divided into two groups according to the presence of reduced LA appendage (LAA) emptying velocity (<25 cm/s) and/or thrombus in the LAA at TEE examination.

Results

Patients with reduced LAA emptying velocity and/or thrombus at TEE examination showed a significantly higher LA volume and increased E/E' ratio. 4-chamber, 2-chamber and global PALS were significantly lower in patients with reduced LAA emptying velocity and/or thrombus (6.8 ± 2.0% vs. 27.5 ± 5.4%, P < 0.0001; 8.6 ± 3.5% vs. 29.4 ± 7.1%, P < 0.0001; 7.9 ± 3.2% vs. 28.5 ± 6.1%, P <0.0001, respectively). Among all variables analyzed, global PALS demonstrated the highest diagnostic accuracy (AUC of 0.92) and, with a cut-off value less than 8.1%, good sensitivity and specificity of 87% and 94%, respectively, to predict LAA thrombus and/or reduced LAA emptying velocity.

Left atrial enlargement and clinical considerations in patients with or without a residual interatrial shunt after closure of the left atrial appendage with the WATCHMAN™-device

BACKGROUND

Interventional closure of the left atrial appendage (LAA) in patients with non-valvular atrial fibrillation, high thromboembolic and bleeding risk or bleeding history is an alternative therapeutic strategy to oral anticoagulation. It is not known if the exclusion of the LAA from the blood circulation affects the left atrial volume (LAV) and consequently its prognostic value or the circulatory performance of the heart in humans.

METHODS

We aimed to prospectively assess potential changes in baseline LAV, left ventricular ejection fraction (LVEF), NT-proBNP-level and the covered distance in the 6-min walk-test 6 weeks and 6 months after LAA closure with the WATCHMAN™ device. We used serial 3-dimensional transthoracic and transesophageal echocardiography to assess LAV, residual interatrial shunt and device performance in 58 consecutive patients with successful LAA closure.

RESULTS

Accurate 3D-echocardiographic data for LAV measurements were evaluable for 51 (91%) patients. Maximum LAV (LAVmax) at baseline was 102.8 ± 30.8 ml and increased significantly to 107.7 ± 32.8 ml after 6 weeks (p < 0.01) and 113.5 ± 34.2 ml after 6 months (p < 0.01). Minimal LAV (LAVmin) increased from 76.9 ± 29.5 ml at baseline to 81.8 ± 30.2 ml after 45 days (p < 0.01) and 82.1 ± 33.3 ml after 6 months (p < 0.01). Similarly, their indexes to BSA (LAVImax and LAVImin) increased significantly, as well. Patients without a residual left-to-right interatrial shunt showed a significantly higher increase in LAVmax or LAVmin. Baseline LVEF, NT-proBNP-level or the distance covered at the 6-min walk test did not significantly change 6 weeks or 6 months after LAA closure.

CONCLUSIONS

LAVmax and LAVmin increase significantly after interventional LAA closure. LA enlargement does not correlate with clinical progression of heart failure. Persistent left-to-right interatrial shunt counteracts the LA enlargement. A reduced LA compliance after exclusion of the LAA from the blood circulation with consecutive increase in LA pressure may be a potential cause of LA enlargement and warrants further investigation.

TRIAL REGISTRATION

German Clinical Trials Register ID: DRKS00010768 ; Registration Date 07.07.2016.

Autonomic dysfunction is associated with cardiac remodelling in heart failure patients

Aims

Orthostatic hypotension (OH) is a cardinal sign of autonomic dysfunction and a common co‐morbidity in heart failure (HF). The role of autonomic dysfunction in the development of structural cardiac anomalies in HF patients has not been sufficiently explored. We aimed to assess relations between orthostatic blood pressure (BP) responses during active standing and echocardiographic changes in a series of patients admitted for HF.

Methods and results

One hundred and forty‐nine patients hospitalized for HF [mean age: 74 years; 30% women; ejection fraction (LVEF) 40 ± 16%] were examined with conventional echocardiograms and active‐standing test. Associations of cardiac remodelling parameters with the difference between supine and standing (after 3 min) systolic/diastolic BP were examined. Systolic BP decreased (−1.1 ± 15 mmHg), whereas diastolic BP increased (+1.0 ± 9.5 mmHg) after 3 min of active standing. A total of 34 patients (23%) met conventional OH criteria; i.e. systolic/diastolic BP decreases by ≥20/10 mmHg. In the multivariable linear regression analysis, adjusted for traditional cardiovascular risk factors and LVEF, a decrease in systolic BP upon standing was associated with greater left atrial volume [β per −10 mmHg: 2.37, standard error (SE) = 1.16, P = 0.043], and greater left ventricular mass (β per −10 mmHg: 5.67, SE = 2.24, P = 0.012), but not with other echocardiographic parameters. No significant associations were observed between signs of cardiac remodelling and decrease in diastolic BP.

Conclusions

Orthostatic decrease in systolic BP among older HF patients is associated with structural cardiac changes such as increased left atrial volume and left ventricular mass, independently of traditional risk factors and left ventricular dysfunction.

Left atrial appendage function assessment and thrombus identification

Background

The diagnosis of thrombus in the left atrium in patients with persistent atrial fibrillation (AF) and may be inconsistent because of variability in thrombus morphology. In some cases it is challenging and requires unusual approach. New Doppler-derived methods might be helpful to identify such thrombi. We evaluated quantitative differences in mechanical function of the left atrial appendage (LAA) basal segments using tissue Doppler imaging (TDI)and speckle tracking echocardiography (STE) in patients with non-valvular AF with and without LAA thrombus and compared them with SR patients.

Methods

A total of 80 patients with normal left ventricular ejection fraction underwent transesophageal echocardiography (40 patients with SR and 40 patients with AF on oral anticoagulants including patients with LAA thrombus). We analyzed the basal segments of LAA including left lateral ridge (LLR) and baso-medial appendage segment (BMAS). Quantitative analysis was used to calculate peak velocity, average velocity, strain, strain rate and deformation.

Results

In patients with AF the lower LLR strain rate was the sole new STE significant parameter differentiating patients with and without LAA thrombi: − 0.9(− 1.2; − 0.1)s^− 1 vs. − 1.6(− 1.9; − 1.3)s^− 1, (p = 0.004). Additionally, patients in SR demonstrated significantly better peak velocity, average velocity, strain, strain rate and deformation than those with AF (p < 0.001).

Conclusions

LLR appeared to be an appropriate site for measuring Doppler derived parameters. It is possible that the strain rate in LLR area may be a novel parameter correlating with the presence of thrombus in patients with AF.

The Prognostic Significance of Cardiac Structure and Function in Atrial Fibrillation: The ENGAGE AF-TIMI 48 Echocardiographic Substudy

BACKGROUND

Atrial fibrillation (AF) is associated with increased risk for thromboembolism and death; however, the relationships between cardiac structure and function and adverse outcomes among individuals with AF are incompletely understood.

METHODS

The Effective Anticoagulation with Factor Xa Next Generation in AF-Thrombolysis in Myocardial Infarction 48 study tested the once-daily oral factor Xa inhibitor edoxaban in comparison with warfarin for the prevention of stroke (ischemic or hemorrhagic) or systemic embolism in 21,105 subjects with nonvalvular AF and increased risk for thromboembolic events (CHADS2 score ≥ 2). In a prospective substudy of 971 subjects who underwent transthoracic echocardiography at baseline, Cox proportional hazards models were used to evaluate associations between cardiac structure and function and the risks for death and thromboembolism (ischemic stroke, transient ischemic attack, or systemic embolism).

RESULTS

Over a median follow-up period of 2.5 years, 89 deaths (9.2%) and 48 incident thromboembolic events (4.9%) occurred in 971 subjects. In models adjusted for CHADS2 score, aspirin use, and randomized treatment, larger left ventricular (LV) end-diastolic volume index (hazard ratio per 1 SD [12.9 mL/m(2)], 1.49; 95% CI, 1.16-1.91) and higher LV filling pressures measured by E/e' ratio (hazard ratio per 1 SD [4.6], 1.32; 95% CI, 1.08-1.61) were independently associated with increased risks for death. E/e' ratio > 13 significantly improved the prediction of death beyond clinical factors alone. No features of cardiac structure and function were independently associated with thromboembolism in this population. Findings were similar when adjusted for CHA2DS2-VASc score in place of CHADS2 score.

CONCLUSIONS

In a contemporary population of patients with AF at increased risk for thromboembolic events, larger LV size and higher filling pressures were significantly associated with increased risk for death, but neither left atrial nor LV measures were associated with thromboembolic risk. LV size and filling pressures may help identify patients with AF at increased risk for death.

Transesophageal Echocardiography in Atrial Fibrillation

Transesophageal echocardiography (TEE) plays an important role in atrial fibrillation (AF), mainly to detect the presence of left atrial appendage (LAA) thrombus. It is useful in direct current cardioversion (DCC) guidance and for AF ablation and LAA occlusion. With the increasing number of patients affected by AF, the use of TEE will grow and become an important screening modality for LAA thrombus. Future direction includes broader multi-institutional use; further tools to risk stratify patients; and the use of a new spectrum of oral anticoagulants and their cost-effectiveness in patients with AF undergoing DCC, AF ablation, and LAA occlusion.

Stroke Risk Factors Beyond the CHA₂DS₂-VASc Score: Can We Improve Our Identification of "High Stroke Risk" Patients With Atrial Fibrillation?

The prevention of stroke and other thromboembolic events plays a crucial role in the management of patients with atrial fibrillation. Not all patients with atrial fibrillation are equal in terms of thromboembolic risk; therefore, not all will benefit from oral anticoagulation treatment. The general principle is that the expected benefit of anticoagulation in reduction of thromboembolic risk must exceed the expected harm caused by possible bleeding. Some guidelines have focused on a categorical approach to stroke prevention, with a focus on identifying patients at high risk for oral anticoagulation. Various current guidelines recommend assessment of stroke risk using the CHADS2 or CHA2DS2-VASc scores to initially detect patients at low risk who require no antithrombotic therapy. However, the scores do not incorporate all possible risk factors causing a high thromboembolic risk. Factors such as impaired renal function, obstructive sleep apnea, and echocardiographic and biochemical or coagulation parameters can also predict adverse thromboembolic events. The present review aims to describe biomarkers whether blood, urine, imaging (cardiac or cerebral), or clinical that go beyond the CHA2DS2-VASc score and potentially aid stroke risk assessment. Although useful in some cases, the presented parameters should be perhaps used to further refine initial identification of patients at low risk, after which effective stroke prevention can be offered to those with ≥1 additional stroke risk factors.

Monocyte-platelet aggregates and CD11b expression as markers for thrombogenicity in atrial fibrillation

BACKGROUND

A strong interdependence is known between atrial fibrillation (AF), inflammation and thrombogenesis. Monocyte-platelet aggregates (MPAs) are sensitive markers of platelets and monocyte activation. It is not known whether MPAs are associated with thrombogenicity in AF. Therefore, we examined differences in the content of MPAs and CD11b expression in patients with AF in dependence of the presence of atrial thrombus formation.

METHODS

107 patients with symptomatic AF underwent transesophageal echocardiography (TEE) before planned cardioversion or pulmonary vein isolation. Flow-cytometric quantification analysis was done on the day of performed TEE to determine the content of MPAs and the expression of CD11b on monocytes and granulocytes.

RESULTS

Compared to patients without thrombus (n = 80) those with an echocardiographic proven left atrium (LA) thrombus (n = 27) showed an increased extent of the risk factors age, diabetes and heart failure. The content of MPAs (147 ± 12 vs. 311 ± 29 cells/µl, p < 0.001) as well as the CD11b expression on monocytes (p < 0.05) and granulocytes (p < 0.05) were strongly associated with the existence of a LA thrombus. The content of MPAs and the CD11b expression remained independent predictors for LA thrombus after adjustment in logistic regression analysis and negatively correlated with left atrial appendage flow velocity. MPAs above 170 cells/µl (OR 34.2, p = 0.01) had a sensitivity of 96 % and a specificity of 73 % for predicting LA-thrombus.

CONCLUSIONS

The content of MPAs and the CD11b expression on monocytes and granulocytes are increased in AF-patients with proven thrombus formation. They seem to be appropriate biomarkers for stratification of thromboembolic risk in patients with AF.

Untreated atrial fibrillation in the United Kingdom: Understanding the barriers and treatment options

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major preventable cause of stroke and hospitalization. Its prevalence is on the rise worldwide and experts believe it will continue to rise for the foreseeable future, due to the ageing population and increased survival from conditions associated with AF. Despite the fact that oral anticoagulation is effective in preventing strokes due to AF, there is extensive evidence suggesting this therapy remains underused. Barriers to the prescription of anticoagulation include patients' age per se, comorbidities, inadequate risk stratification, perceived risk of falls and bleeding, and the difficulty in achieving a stable international normalized ratio (INR) on warfarin. Also, asymptomatic patients with AF may not be identified and therefore not be candidates for anticoagulation. Physicians need continued better education on the identification of patients at risk of stroke and management of oral anticoagulation. This article reviews the barriers to anticoagulation in patients with AF in the United Kingdom and considers how those barriers may be overcome.

Which method of left atrium size quantification is the most accurate to recognize thromboembolic risk in patients with non-valvular atrial fibrillation?

BACKGROUND

Left atrial (LA) size is a predictor of cardiovascular outcomes in patients in sinus rhythm, whereas conflicting results have been found in atrial fibrillation (AF). This study aims to: (1) Evaluate the accuracy of LA size to identify surrogate markers of an increased thromboembolic risk in patients with AF; (2) Assess the best method to evaluate LA size in this setting.

METHODS

Cross-sectional study enrolling 500 consecutive patients undergoing transthoracic and transesophageal echocardiography evaluation during a non-valvular AF episode. LA size was measured on transthoracic echocardiography using several methods: anteroposterior diameter, area in four-chamber view, and volumes by the ellipsoid, single- and biplane area-length formulas. Surrogate markers of stroke were evaluated by transesophageal echocardiography: LA appendage (LAA) thrombus, LAA low flow velocities, dense spontaneous echocardiographic contrast and LA abnormality.

RESULTS

Except for non-indexed anteroposterior diameter, increased LA size quantified by all the other methods showed a moderate to high discriminatory power to identify all the surrogate markers of stroke. A higher accuracy was observed for indexed LA area in four-chamber view (LAA thrombus: AUC = 0.708, CI95% 0.644- 0.772, p<0.001; LAA low flow velocities: AUC = 0.733, CI95% 0.674- 0.793, p<0.001; dense spontaneous echocardiographic contrast: AUC = 0.693, CI95% 0.638- 0.748, p<0.001; LA abnormality: AUC = 0.705, CI95% 0.654-0.755, p<0.001), indexed single-plane area-length volume (LAA thrombus: AUC = 0.701, CI95% 0.633-0.770, p<0.001; LAA low flow velocities: AUC = 0.726, CI95% 0.660-0.792, p<0.001; dense spontaneous echocardiographic contrast: AUC = 0.673, CI95% 0.611-0.736, p<0.001; LA abnormality: AUC = 0.687, CI95% 0.629-0.744, p<0.001), and indexed biplane area-length volume (LAA thrombus: AUC = 0.707, CI95% 0.626-0.788, p<0.001; LAA low flow velocities: AUC = 0.737, CI95% 0.664-0.810, p<0.001; dense spontaneous echocardiographic contrast: AUC = 0.651, CI95% 0.578-0.724, p<0.001; LA abnormality: AUC = 0.683, CI95% 0.617-0.749, p<0.001), without significant difference between them. Indexed LA area in four-chamber view and indexed area-length volumes also were independent predictors of surrogate markers of stroke.

CONCLUSIONS

Left atrium enlargement is associated with an increased prevalence of surrogate markers of stroke in patients with non-valvular AF. Indexed LA area in four-chamber view and indexed area-length volumes displayed the strongest association.

Evaluation of left atrial deformation to predict left atrial stasis in patients with non-valvular atrial fibrillation - a pilot-study

BACKGROUND

Speckle tracking-derived strain and strain rate are recently available parameters to assess left atrial (LA) deformation. We hypothesized that such new parameters could be of interest to evaluate the risk of LA stasis among patients with atrial fibrillation (AF).

METHODS

Single-centre study enrolling all patients with non-valvular AF lasting longer than 48 hours for whom no therapeutic anticoagulation was given in the preceding 3 weeks and who were assessed through transesophageal and transthoracic echocardiogram during a 6 month time interval. LA deformation was assessed by transthoracic echocardiogram through speckle tracking analysis, whereas LA stasis parameters were sought on transesophageal echocardiogram.

RESULTS

Among the 82 assessed patients, LA appendage thrombi or sludge were found in 16 (19.5%). A moderate positive correlation was found between peak positive strain rate and maximum emptying velocity (r = 0.589; P <0.001) and peak positive strain rate and maximum filling velocity of the LA appendage (r = 0.651; P <0.001). Peak negative strain rate was also found to be associated with both maximum emptying velocity (r = -0.513; P <0.001) and maximum filling velocity of the LAA (r = -0.552; P <0.001). AF duration, peak negative strain rate and time-to-peak positive strain were independent predictors of LAA thrombi or sludge on multivariate analysis logistic regression. The area under the curve for the estimated probabilities using the obtained logistic regression model was 0.89 (95%CI 0.81-0.96; P <0.001).

CONCLUSION

Our findings suggest that LA mechanical dysfunction assessed through speckle tracking may be of interest to predict LA stasis in the setting of AF.