Spontaneous echo contrast: where there's smoke there's fire

Does Spontaneous Echo Contrast in the Left Atrial Appendage Increase Thromboembolism Risk After Left Atrial Appendage Closure? A Retrospective Study on Its Impact on Device-Related Thrombosis and Arterial Thromboembolic Events

Background: Left atrial appendage closure (LAAC) prevents arterial thromboembolic events (ATEs) in nonvalvular atrial fibrillation (AF). Spontaneous echo contrast (SEC) is an independent risk factor for left atrial appendage (LAA) thrombosis; however, there is little knowledge about the relationship between preoperative SEC and the increased risk of device-related thrombosis (DRT) or ATEs in patients with AF who have undergone LAAC. Methods: This retrospective study focused on patients with nonvalvular AF who successfully underwent LAAC surgery. Transesophageal echocardiography (TEE) was used to assess preoperative LAA status. SEC in LAA Grades 0-2 was defined as LAASEC-, and Grades 3-4 or previously diagnosed LAA thrombus formation as LAASEC+. Results: A total of 519 AF patients (432 in LAASEC- group and 87 in LAASEC+ group) who underwent LAAC were included. At the 1-year follow-up, there was no significant difference in the incidence of DRT (2.5 vs. 3.8%, p = 0.636), ATEs (0.5 vs. 0%, p = 0.525), and all-cause mortality (2.1% vs. 2.3%, p = 0.899) between the LAASEC- group and the LAASEC+ group. However, the LAASEC+ group had higher proportions of cauliflower-type LAA and ≥ 3 lobes. Conclusions: The difference in preoperative LAA thrombosis or LAASEC was not related to the incidence of DRT or ATEs in AF patients within 1 year after LAAC.

Design and Validation of a High-Fidelity Left Atrial Cardiac Simulator for the Study and Advancement of Left Atrial Appendage Occlusion

PURPOSE

Atrial fibrillation (AF) is the most common chronic cardiac arrhythmia that increases the risk of stroke, primarily due to thrombus formation in the left atrial appendage (LAA). Left atrial appendage occlusion (LAAO) devices offer an alternative to oral anticoagulation for stroke prevention. However, the complex and variable anatomy of the LAA presents significant challenges to device design and deployment. Current benchtop models fail to replicate both anatomical variability and physiological hemodynamics, limiting their utility. This study introduces a novel left atrial cardiac simulator that incorporates patient-derived LAA models within a benchtop circulatory flow loop, enabling high-fidelity LAAO device testing and development.

METHODS

A rigid, patient-derived left atrium (LA) model was 3D printed from segmented MRI data and modified to accommodate attachment of patient-specific LAA models. A library of LAA geometries was fabricated using silicone casting techniques to replicate the mechanical properties of native tissue. The LA-LAA model was integrated into a circulatory flow loop equipped with a pulsatile pump, pressure sensors, and flow probes, allowing real-time hemodynamic analysis. System tunability was demonstrated by varying heart rate, stroke volume, resistance, and compliance to simulate physiological and pathological conditions.

RESULTS

The simulator accurately replicated LA pressure and flow waveforms, closely approximating physiological conditions. Changes in heart rate, stroke volume, and compliance effectively modulated LAP and LA inflow before and after LAAO. Distinct pressure and flow waveforms were observed with different LAA geometries. Hemodynamic analysis revealed increased left atrial pulse pressure after occlusion, with the greatest increase occurring after complete exclusion of the LAA. The simulator facilitated the evaluation of LAAO device performance, including metrics such as seal and PDL, and served as an effective training tool for iterative device deployment and recapture with visual and imaging-guided feedback.

CONCLUSIONS

The left atrial cardiac simulator offers a highly tunable and realistic platform for testing and developing LAAO devices. It also serves as an effective procedural training tool, allowing for the simulation of patient-specific anatomical and hemodynamic conditions. By enabling these advanced simulations, the simulator enhances pre-procedural planning, device sizing, and placement. This innovation represents a significant step toward advancing personalized medicine in atrial fibrillation management and improving LAAO outcomes.

Echocardiographic assessment of left atrial appendage morphology and function-an expert proposal by the German Working Group of Cardiovascular Ultrasound

The left atrial appendage is a blind ending cardiac structure prone to blood stasis due to its morphology. This structure is a preferred region of thrombogenesis in relation to reduced myocardial contractility of the atrial wall. Blood stasis occurs primarily in low flow conditions. One of the tasks of echocardiography is the analysis of morphology and function of the left atrial appendage. The detection of thrombi by echocardiography is difficult and must be carried out thoroughly and carefully to avoid potential complications-especially in the context of rhythm control. The assessment of thromboembolic risk, especially in patients with unknown and presumed atrial fibrillation is a second challenge by characterizing atrial function and flow conditions in the left atrial appendage. Thus, this proposal focuses on the obvious problems of echocardiography when assessing left atrial appendage and the role of this method in planning a potential interventional closure of left atrial appendage.

Enhancing stroke risk stratification in atrial fibrillation through non-Newtonian blood modelling and Gaussian process emulation

Atrial fibrillation (AF) is the most common heart arrhythmia, linked to a five-fold increase in stroke risk. The left atrial appendage (LAA), prone to blood stasis, is a common thrombus formation site in AF patients. The LAA can be classified into four morphologies: broccoli, cactus, chicken wing and windsock. Stroke risk prediction in AF typically relies on demographic characteristics and comorbidities, often overlooking blood flow dynamics. We developed patient-specific non-Newtonian models of blood flow, dependent on fibrinogen and haematocrit, to predict changes in LAA viscosity, aiming to predict stroke in AF patients. We conducted 480 computational fluid dynamics (CFD) simulations using the non-Newtonian model across the four LAA morphologies for four virtual patient cohorts: AF + Covid-19, AF + pathological fibrinogen, AF + normal fibrinogen, and healthy controls. Gaussian process emulators (GPEs) were trained on this in silico cohort to predict average LAA viscosity at near-zero computational cost. GPEs demonstrated high accuracy in AF cohorts but lower accuracy when the chicken wing GPE was applied to other morphologies. Global sensitivity analysis showed fibrinogen significantly influenced blood viscosity in all AF cohorts. The chicken wing morphology exhibited the highest viscosity, while the AF + Covid-19 cohort had the highest viscosity. Our non-Newtonian model in CFD simulations confirmed fibrinogen's substantial impact on blood viscosity at low shear rates in the LAA, suggesting that combining blood values and geometric parameters of the LAA into GPE training could enhance stroke risk stratification accuracy. KEY POINTS: Fibrinogen has a significant effect on blood viscosity in the left atrial appendage (LAA) at low shear rates. Gaussian process emulators (GPEs) can predict the viscosity of blood in the LAA at near-zero computational cost. Out of all LAA morphologies, the chicken wing morphology exhibited the highest average blood viscosity. High average blood viscosity in the LAA of atrial fibrilation + Covid-19 patients was observed due to high fibrinogen levels in this cohort. Combining blood values and geometric parameters of the LAA into GPE training could enhance stroke risk stratification accuracy.

A Phantom-Free Approach for Estimating the Backscatter Coefficient of Aggregated Red Blood Cells Applied to COVID-19 Patients

The ultrasound backscatter coefficient (BSC) is a frequency-dependent quantity intrinsic to biological tissues that can be recovered from backscattered radio frequency (RF) signals, granted acquisitions on a reference phantom (RP) are available under the same system's settings. A phantom-free (PF) BSC estimation method is proposed based on Gaussian-shaped approximation of the point spread function (PSF) (electronics and piezoelectric characteristics of the scanner's probe) and the effective medium theory combined with the structure factor model (EMTSFM), albeit the proposed approach is amenable to other models. Meanwhile, the total attenuation due to intervening tissues is refined from its theoretical value, which is based on reported average behaviors of tissues, while allowing correction for diffraction due to the probe's geometry. The RP method adapted to a similar approach except for the Gaussian approximation is also presented. The proposed PF and RP methods were compared on ten COVID-19 positive patients and 12 control subjects with measures on femoral veins and arteries. In this context, red blood cells (RBCs) are viewed as scatterers that form aggregates increasing the backscatter under the COVID-19 inflammatory condition. The considered model comprises five parameters, including the mean aggregate size estimated according to the polydispersity of aggregates' radii, and anisotropy of their shape. The mean aggregate size over the two proposed methods presented an intraclass correlation coefficient (ICC) of 0.964 for consistency. The aggregate size presented a significant difference between the two groups with either two methods, despite the confounding effect of the maximum Doppler velocity within the blood vessel and its diameter.

A gray zone: Role of transesophageal echocardiography before atrial tachycardia catheter ablation

INTRODUCTION

There is a lack of studies in the literature directly investigating the relationship between atrial tachycardia (AT) and left atrial (LA)/left atrial appendage (LAA) thrombus, and current guidelines do not provide strong recommendations regarding the use of transesophageal echocardiography (TEE) before AT catheter ablation. This study aims to elucidate the relationship between AT and the presence of LA/LAA thrombus and contribute to the literature on the use of TEE before AT catheter ablation.

METHODS

This single-center retrospective observational study screened patients who underwent TEE between February 10, 2019, and February 10, 2023. Patients were assigned to the AT patient and control groups. TEE was conducted to exclude thrombus in the AT ablation group. The control group included patients who underwent TEE for interatrial septum evaluation and had LA imaging during TEE but did not have atrial arrhythmia. To mitigate bias between the AT patient group and the control group, they were randomized 1:1 using propensity-score matching (PSM). Following randomization, each group consisted of 49 patients.

RESULTS

All analyses were conducted after PSM. There were no statistically significant differences between the AT patient and control groups in terms of baseline clinical characteristics and echocardiographic features. Additionally, no significant differences were found between the blood viscosities calculated at low and high shear rates in both groups. The study revealed a significant difference between the two groups in the presence of LA spontaneous echo contrast (SEC) (24.5% in AT group vs 0% in Control group, p = .001), but not in the presence of thrombi (8.2% in AT group vs 0% in Control group, p = .117).

CONCLUSION

Compared to the control group, the presence of SEC was significantly higher in the AT patient group. The increased frequency of SEC in AT patients suggests the hypothesis that AT may contribute to LA stasis. The routine use of TEE before AT catheter ablation remains controversial, despite the presence of LA thrombus and SEC in the AT patient group. The clinical assessment of thrombus presence before the procedure must be conducted on a patient-specific basis.

[Abdominal aortic malformation in 2 dogs]

Aneurysms of the abdominal aorta are only sporadically documented in the veterinary literature. This publication describes 2 canine cases in which abdominal aortic malformation was detected by sonography and confirmed by computed tomography. In one case a histological diagnosis of an aortic aneurysm was possible.One dog showed posterior weakness, in the second dog the aortic aneurysm had been noticed sonographically during a routine examination.In the patient with the proven aortic aneurysm, it may be presumed that a hemodynamically relevant component in consequence to the altered flow profile and occurring turbulence exists. In accordance with human medical standards, regular monitoring of these patients, both clinically and by ultrasound, would therefore appear to be useful in order to be able to detect the occurrence or progression of secondary hemodynamic changes and possible thrombus formation at an early stage. In contrast, the second case presented here has not shown any clinical signs with regard to the abdominal vascular malformation up to the present time.

Relationship of inflammatory indices with left atrial appendage thrombus or spontaneous echo contrast in patients with atrial fibrillation

BACKGROUND

Inflammatory indices derived from complete blood tests have been reported to be associated with poor outcomes in patients with atrial fibrillation (AF). The data about the relationship between inflammatory indices and left atrial appendage thrombus (LAAT) or dense spontaneous echo contrast (SEC) are limited.

AIM

To explore the value of inflammatory indices for predicting the presence of LAAT or dense SEC in nonvalvular AF patients.

METHODS

A total of 406 patients with nonvalvular AF who underwent transesophageal echocardiography were included and divided into two groups based on the presence (study group) or absence (control group) of LAAT or dense SEC. Inflammatory indices, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR), were calculated from complete blood analysis. The associations of inflammatory indices with LAAT/dense SEC were analyzed using logistic regression.

RESULTS

LAAT and dense SEC were detected in 11 (2.7%) and 42 (10.3%) patients, respectively. The PLR only showed an association with LAAT/dense SEC in the univariate model. Elevated NLR (odds ratio [OR] = 1.48, 95% confidence interval [CI]: 1.11-1.98, P = 0.007) and reduced LMR (OR = 0.59, 95%CI: 0.41-0.83, P = 0.003) were found to be independent risk factors for the presence of LAAT/dense SEC. The areas under the NLR and LMR curves for predicting LAAT/dense SEC were 0.73 (95%CI: 0.66-0.80, P < 0.001) and 0.73 (95%CI: 0.65-0.81, P < 0.001), respectively, while the cutoff values were 2.8 (sensitivity: 69.8%; specificity: 64.0%) and 2.4 (sensitivity: 71.7%; specificity: 60.6%), respectively.

CONCLUSION

Increased NLR and decreased LMR may predict LAAT/dense SEC in patients with nonvalvular AF.

Viscoelastic coagulation monitoring parameters in cats with acute arterial thromboembolism

BACKGROUND

Hypercoagulability has been documented in cats with cardiac disease. However, hemostatic parameters, including viscoelastic coagulation monitoring (VCM) have not been reported in cats with arterial thromboembolism (ATE).

HYPOTHESIS/OBJECTIVES

Compare VCM parameters in cats with acute cardiogenic ATE and in control cats.

ANIMALS

Sixteen cats with ATE and 30 control cats.

METHODS

Multicenter university-based prospective study. Cardiogenic ATE was diagnosed based on physical examination and by ultrasonographically-diagnosed left atrial enlargement. Viscoelastic coagulation monitor analysis, CBC, serum biochemistry profile and coagulation profile were performed at admission in cats with ATE. Analysis from healthy control cats was performed using blood collected by direct venipuncture. Our objective was comparison of VCM parameters clot time (CT), clot formation time (CFT), alpha angle (Angle), maximum clot formation (MCF), amplitude at 10 and 20 minutes (A10 and A20, respectively) and clot lysis index at 30 and 45 minutes (LI30 and LI45, respectively) between ATE and control cats.

RESULTS

Cats with ATE had a decreased angle compared to control cats, with a median (range) of 43° (30-48°) compared to 47° (14-59°; P = .01). The parameters A10, A20 and MCF were decreased in ATE cats compared to control cats with a median (range) of 19 units (8-32) compared to 22 units (6-38), 24.5 units (11-40) compared to 29 units (10-47) and 29.5 units (13-44) compared to 33.5 units (14-53), respectively (P = .01, .01 and .01, respectively). The parameters CT, CFT, LI30 and LI45 were similar between groups (P = .22, .09, .62 and .34, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Cats with cardiogenic ATE cats have VCM parameters consistent with hypocoagulability compared with healthy cats.

Prediction of spontaneous echocardiographic contrast within the left atrial appendage in cardiac computed tomography of patients with atrial fibrillation

This study aimed to assess the predictors of spontaneous echocardiographic contrast (SEC) using left atrial appendage (LAA) findings in cardiac computed tomography (CT) of patients with atrial fibrillation (AF). We retrospectively analyzed cardiac CT findings of the LAA, including morphology, volume, and filling defects, of 641 patients who underwent transesophageal echocardiography (TEE) prior to pulmonary vein isolation (PVI) from January 6, 2013 through December 16, 2019 at our institution. We investigated potential associated factors that might be predictors of SEC using cardiac CT findings and computed a receiver operator characteristic, choosing a threshold value at which the likelihood of SEC could be predicted based on the LAA volume indexed for body size. SEC correlated significantly with indexed LAA volume (P < 0.001; odds ratio [OR], 1.31; 95% confidence interval [CI], 1.17-1.48) of 7.75 cm3/m2 or greater (sensitivity, 76.0%; specificity, 57.7%), LAA early filling defect (P = 0.005; OR, 2.72; 95% CI, 1.35-5.48), a history of persistent AF (P < 0.001; OR, 3.81; 95% CI, 1.86-7.80), and LAA flow velocity (P < 0.001; OR, 0.97; 95% CI, 0.96-0.99). Findings of LAA in cardiac CT can allow for the noninvasive estimation of SEC to determine the need for additional TEE investigation and the need to obtain additional information for risk stratification and management of thromboembolic events in patients with AF.

Systemic thrombo-embolic events in a middle-aged male with Loeffler endocarditis without peripheral eosinophilia-a case report

BACKGROUND

Loeffler-endocarditis (LE) is considered a chronic restrictive cardiomyopathy and manifestation of eosinophilic myocarditis characterized by eosinophilic infiltration. LE is a rare underdiagnosed disease and associated with high morbidity and mortality.

CASE PRESENTATION

We report a case of a 46-year-old man suffering from LE associated with thromboembolic events without peripheral eosinophilia. The patient presented with typical clinical signs of acute onset of limb ischaemia, predominantly on the right limb, indicating immediate iliacal thrombectomy and due to a severe compartment syndrome additional fasciotomy. Total occlusion also of left popliteal artery suggesting an impaired chronic and aggravated impaired perfusion indicated also urgent left sided revascularization. Subsequent echocardiography revealed severe left ventricular dysfunction with a striking amount of spontaneous echo-contrast, noticeable in the left ventricular cavity. Furthermore the initial CT scan demonstrated asymptomatic left kidney- and brain infarctions. Diagnostic workup including endomyocardial biopsy (EMB) of the left ventricle, uncovered an underlying LE without peripheral eosinophilia.

CONCLUSIONS

This case demonstrates and highlights the findings, treatment and outcome of a patient with LE and associated thrombo-embolic events without peripheral eosinophilia and emphazises the importance of awareness for LE in patients presenting with an acute cardiac decompensation and thrombo-embolic events. EMB should be performed early in unstable patients unsuitable for cardiovascular magnetic resonance imaging.

Association of spontaneous echo contrast with Systemic Immune Inflammation Index in patients with mitral stenosis

OBJECTIVE

Spontaneous echo contrast (SEC) is the appearance of swirling, smoke-like echoes in the left atrium (LA) and is accepted as an independent predictor of thromboembolic risk. There is an established relationship between the inflammatory state and the prothrombotic state. Therefore, we investigated the relationship between the Systemic Immune Inflammation Index (SII), a new inflammation parameter introduced recently, and SEC in patients with mitral stenosis (MS).

MATERIAL AND METHODS

A total of 262 patients who underwent percutaneous mitral valvuloplasty (PMBV) for MS were included in this study. The patients were divided into two groups: patients with MS complicated by SEC and patients with MS without SEC, based on whether SEC occurred in the LA.

RESULTS

There were 79 patients (mean age 47.1 ± 6.6, 30.3% male gender) in the SEC (+) group, while there were 183 patients (mean age 46.4 ± 8.6, 29.5% male gender) in the SEC (-) group. In multivariate analysis, high levels of SII were an independent risk factor for SEC in patients with MS (OR: 1.001, 95% confidence interval (CI): 1.000-1.001, p<0.001) together with high levels of C-reactive protein (OR: 1.145, 95% CI: 1.027-1.277, p=0.014). The receiver operating characteristics (ROC) curve analysis showed that at a cutoff value of 547.6 for SII to predict SEC with 74.6% sensitivity and 77.6% specificity (area under ROC curve=0.736 (95% CI: 0.668-0.805), p<0.001).

CONCLUSION

Our study showed that the SII levels were independently associated with SEC in patients with MS.

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.

Point-of-Care Resuscitative Echocardiography Diagnosis of Intracardiac Thrombus during cardiac arrest (PREDICT Study): A retrospective, observational cohort study

Background

Point-of-care ultrasound (POCUS) has been previously studied in cardiac arrest, without definitive markers for futile resuscitation efforts identified. Intracardiac thrombus during cardiac arrest has not been systematically studied. Our objective was to describe the incidence of intracardiac thrombus and spontaneous echo contrast found during cardiac arrest.

Methods

A two hospital, retrospective, observational cohort study of 56 cardiac arrest patients who were assessed with POCUS (between January 1st, 2017 to April 30th, 2020). Eligible studies were reviewed for echocardiographic findings (e.g. presence of intracardiac thrombus or spontaneous echo contrast), baseline patient demographics, cardiac arrest-related data, and clinical outcomes. Primary outcome was in-hospital mortality.

Results

Fifty-six intra-arrest POCUS echocardiograms were identified (out of 738 out-of-hospital cardiac arrests). The median patient age was 63 years (interquartile range [IQR]: 51–72), with 25% female patients, and median Charlson Comorbidity Index score of 4 (IQR: 2–6). The incidence of intracardiac thrombus was 21 out of 56 patients (38%). Time-to-new thrombus formation during cardiac arrest was approximately 6 minutes (IQR: 2-–8). All patients with intracardiac thrombus during cardiac arrest had termination of resuscitation.

Conclusions

Intracardiac thrombus is potentially common during out-of-hospital cardiac arrests and was observed more frequently in those in whom termination of resuscitation was recommended. However, this is only hypothesis-generating at this time, and further study is required to determine if the presence of intracardiac thrombus may be used as a potential marker of resuscitation futility.

Non-Newtonian blood rheology impacts left atrial stasis in patient-specific simulations

The lack of mechanically effective contraction of the left atrium (LA) during atrial fibrillation (AF) disturbs blood flow, increasing the risk of thrombosis and ischemic stroke. Thrombosis is most likely in the left atrial appendage (LAA), a small narrow sac where blood is prone to stagnate. Slow flow promotes the formation of erythrocyte aggregates in the LAA, also known as rouleaux, causing viscosity gradients that are usually disregarded in patient-specific simulations. To evaluate these non-Newtonian effects, we built atrial models derived from 4D computed tomography scans of patients and carried out computational fluid dynamics simulations using the Carreau-Yasuda constitutive relation. We examined six patients, three of whom had AF and LAA thrombosis or a history of transient ischemic attacks (TIAs). We modeled the effects of hematocrit and rouleaux formation kinetics by varying the parameterization of the Carreau-Yasuda relation and modulating non-Newtonian viscosity changes based on residence time. Comparing non-Newtonian and Newtonian simulations indicates that slow flow in the LAA increases blood viscosity, altering secondary swirling flows and intensifying blood stasis. While some of these effects are subtle when examined using instantaneous metrics like shear rate or kinetic energy, they are manifested in the blood residence time, which accumulates over multiple heartbeats. Our data also reveal that LAA blood stasis worsens when hematocrit increases, offering a potential new mechanism for the clinically reported correlation between hematocrit and stroke incidence. In summary, we submit that hematocrit-dependent non-Newtonian blood rheology should be considered when calculating patient-specific blood stasis indices by computational fluid dynamics.

Neutrophil extracellular traps in feline cardiogenic arterial thrombi: a pilot study

OBJECTIVES

The aim of this study was to investigate the spatial distribution of neutrophil extracellular traps (NETs) in cardiogenic arterial thromboembolism (CATE). Specifically, we aimed to examine the related structural features of NETs in feline arterial thrombi in relation to their arterial locations.

METHODS

Paraffin-embedded aortic bifurcations from nine cats with hypertrophic cardiomyopathy (four with CATE and five without) were deparaffinized, and NETs were identified by immunodetection based on colocalization of cell-free DNA, citrullinated histone H3 and neutrophil elastase. The distribution of NETs in thrombi within the aortic bifurcations and common iliac arteries (CIAs) was compared based on their proximity to the descending aorta (proximal, mid, distal). Ten random fields per section were captured at × 10 and × 20 magnification for each section of the clot and analyzed.

RESULTS

The distributions of NETs in thrombi within the aortic bifurcation and CIAs were found to differ in relation to their assigned zones (proximal, mid, distal; P = 0.04); NETs were concentrated mostly in the proximal region in the aortic bifurcations (47.56%, interquartile range [IQR] 14.07-77.95) and CIAs (44.69%, IQR 24.65-85.28), compared with the distal regions (2.69%, IQR 0.10-50.04 [P = 0.027]; 7.08%, IQR 1.27-59.33 [P = 0.02]).

CONCLUSIONS AND RELEVANCE

The variation in NET distribution within arterial thrombi may shed light on the pathogenesis of thrombus growth. This may be due to possible neutrophil entrapment or variations in shear stress.

The Comparison of the Diagnostic Value of Left Atrial Pulmonary Vein Single-Phase and Dual-Phase Enhanced CT Scanning for Left Atrial Appendage Thrombosis and SEC in Patients with Atrial Fibrillation

Objective

The accuracy of left atrial pulmonary vein CT enhanced single-phase and dual-phase scanning in the detection of left atrial appendage (LAA) thrombosis and spontaneous echo contrast (SEC) before radio frequency ablation was compared in atrial fibrillation patients, so as to optimize the scanning scheme.

Methods

78 patients with atrial fibrillation who were admitted to Cangzhou Central Hospital from October 2020 to September 2021 and underwent bilateral enhanced CT scan of left atrial pulmonary vein and transesophageal echocardiography (TEE) examination for planned frequency ablation were selected. TEE results were used as the "gold standard" to compare the diagnostic efficacy of the first phase, second phase, and double-phase comprehensive mode of enhanced left atrial pulmonary vein CT in detecting left atrial thrombosis and SEC.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9%, 84.1%, 42.1%, and 98.3%, respectively, in the detection of left atrial thrombosis and SEC by the first phase of CT enhanced scan. The sensitivity, specificity, positive predictive value, and negative predictive value were 22.2%, 98.6%, 66.6%, and 90.7%, respectively, in the detection of left atrial thrombosis and SEC by the second phase of CT enhanced scan. The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9%, 84.1%, 42.1%, and 98.3%, respectively, in the detection of left atrial thrombosis and SEC by the double-phase comprehensive mode of CT enhanced scan. There was no statistically significant difference in the accuracy of CT diagnosis of left atrial appendage thrombosis and SEC between the three modes of the first phase, the second phase, and the double-phase comprehensive CT (P > 0.05). The mean effective radiation dose of double-phase enhanced scan was 7.49 ± 1.02 mSv.

Conclusion

Single-phase enhanced CT scan of left atrial pulmonary vein can meet clinical requirements and significantly reduce the radiation dose compared with double-phase enhanced CT scan. Therefore, it is recommended as an initial screening examination for patients with atrial fibrillation before radiofrequency ablation.

Clinical Utility of the Transthoracic Echocardiogram for Isolated Lacunar Infarcts: A Single-Center Experience

BACKGROUND

Stroke is a prominent and financially burdensome disease. Lacunar strokes are traditionally attributed to small vessel disease rather than cardioemboli, which typically occlude larger arteries. Thus, the benefit of screening for potential sources of cardioemboli in lacunar stroke patients is unclear. We evaluated the clinical utility of the transthoracic echocardiogram performed in patients with lacunar strokes.

METHODS

A single-center retrospective analysis of ischemic stroke patients from January 2013 through December 2017 was performed. Brain magnetic resonance imaging was used to select patients with a single lacunar infarct. Patients presenting with acute symptoms of cardiac disease or an abnormal electrocardiogram were excluded. Transthoracic echocardiogram results were reviewed, and their utility in decision-making was evaluated.

RESULTS

Of the 442 patients at our institution diagnosed with ischemic stroke during the inclusion period, 89 met inclusion criteria. Transthoracic echocardiogram detected a patent foramen ovale in 5.6% of patients, mitral annular calcification in 9.0% of patients, and abnormal wall motion in 4.5% of patients. For all patients, there were no findings that prompted anticoagulation, antibiotic, or surgical intervention. The cost of an inpatient transthoracic echocardiogram is $4100, resulting in $364,900 in unnecessary health care spending.

CONCLUSIONS

Transthoracic echocardiogram appears to have minimal therapeutic value in most patients with lacunar strokes. In stroke patients with no acute symptoms of cardiac disease and a normal electrocardiogram, it may be reasonable to forgo the transthoracic echocardiogram if the brain magnetic resonance imaging shows an isolated lacunar infarct.

Electrolyte Derangements, Hyperlactatemia, and Cardiac Abnormalities Secondary to Refeeding in Three Dogs: Case Report

Three dogs that presented to the emergency service in severely emaciated body conditions were admitted to the hospital for monitoring and refeeding. During their hospitalization, all three dogs developed electrolyte derangements or required supplementation to prevent hypophosphatemia and hypomagnesemia. Additionally, all dogs developed hyperlactatemia, which was suspected to be secondary to thiamine deficiency. Two dogs were reported to have cardiac abnormalities, including cardiac arrhythmias, systolic dysfunction, and spontaneous echogenic contrast. These cases highlight the complexity of refeeding syndrome and its associated complications that extend beyond electrolyte deficiencies.

Prevalence and predictors of left atrial appendage inactivity in patients of rheumatic mitral stenosis in sinus rhythm: An observational study

BACKGROUND

Systemic thromboembolism is a known complication of rheumatic mitral stenosis (RMS) in sinus rhythm (SR). Left atrial appendage (LAA), the commonest site of thrombus formation is usually hypocontractile (inactive) in such patients. We aimed to study the prevalence of LAA inactivity (LAAI) in severe RMS and assess its independent predictors.

METHODS

The study population consisted of 100 patients of severe RMS in SR. Transthoracic and transesophageal echocardiography were done to assess LAA contractile function. Patients with LAA-peak emptying velocity < 25 cm/seconds were defined as having LAAI.

RESULTS

The mean age of study subjects was 31.66±8.69 years and 56% were females. 73% patients had LAAI (Group A), while remaining 27% had normal LAA function (Group B). Mitral-valve area (MVA) and lateral annulus systolic velocity (Sa-wave) were significantly lower while mitral valve mean gradient (MVMG) and serum fibrinogen were significantly higher (all p-values < 0.001) in group A patients. On multivariate binary logistic regression analysis, MVMG (p < 0.001), Sa-wave (p = 0.02), and serum fibrinogen (p = 0.005) were independent predictors of LAAI. Optimal cut-off values of MVMG, Sa-wave and serum fibrinogen for predicting LAAI were 11.5 mm Hg, 6.8 cm/seconds and 300 mg/dl, respectively. Sixty-Seven (90.55%) patients in group A compared to 13(48.1%) in group B had LA/LAA smoke. LAAI was the only independent predictor of left atrium (LA)/LAA smoke with or without associated thrombus.

CONCLUSION

There is high prevalence of LAAI in patients of severe MS in SR. MVMG, Sa-wave, and serum fibrinogen levels are independent predictors of LAAI. LAAI is an independent predictor of LA/LAA smoke with or without associated thrombus.

A Review of Biomarkers for Ischemic Stroke Evaluation in Patients With Non-valvular Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide and results in a significantly increased ischemic stroke (IS) risk. IS risk stratification tools are widely being applied to guide anticoagulation treatment decisions and duration in patients with non-valvular AF (NVAF). The CHA₂DS₂-VASc score is largely validated and currently recommended by renowned guidelines. However, this score is heavily dependent on age, sex, and comorbidities, and exhibits only moderate predictive power. Finding effective and validated clinical biomarkers to assist in personalized IS risk evaluation has become one of the promising directions in the prevention and treatment of NVAF. A number of studies in recent years have explored differentially expressed biomarkers in NVAF patients with and without IS, and the potential role of various biomarkers for prediction or early diagnosis of IS in patients with NVAF. In this review, we describe the clinical application and utility of AF characteristics, cardiac imaging and electrocardiogram markers, arterial stiffness and atherosclerosis-related markers, circulating biomarkers, and novel genetic markers in IS diagnosis and management of patients with NVAF. We conclude that at present, there is no consensus understanding of a desirable biomarker for IS risk stratification in NVAF, and enrolling these biomarkers into extant models also remains challenging. Further prospective cohorts and trials are needed to integrate various clinical risk factors and biomarkers to optimize IS prediction in patients with NVAF. However, we believe that the growing insight into molecular mechanisms and in-depth understanding of existing and emerging biomarkers may further improve the IS risk identification and guide anticoagulation therapy in patients with NVAF.

Porphyromonas gingivalis and left atrial appendage spontaneous echo contrast in atrial fibrillation ablation candidates

Atrial fibrillation (AF) is associated with a fivefold risk of stroke and thrombotic embolism, which are usually derived from the left atrial appendage (LAA). Spontaneous echo contrast (SEC) is known as a risk factor for thrombosis. Porphyromonas gingivalis (P. gingivalis) has some prothrombotic effects and plays a key role in periodontitis and oral-systemic disease connection. We aimed to clarify the relationship between P. gingivalis and LAA SEC among AF patients. A total of 569 AF ablation candidates were enrolled in the present study. LAA SEC was categorized into nondense SEC and dense SEC based on transesophageal echocardiography. Serum immunoglobulin G antibody titers of P. gingivalis fimA subtypes (types I-IV) were measured with an enzyme-linked immunosorbent assay. The levels of antibody titers were categorized into high (> mean + 3 standard deviation) and low values. A total of 513 (90%) patients were included in the nondense SEC group, and 56 (10%) were included in the dense SEC group. Multivariate regression analysis revealed that the high-value serum antibody titers of P. gingivalis types II and IV were independently associated with dense SEC [type II: adjusted odds ratio (OR) 2.220; 95% confidence interval (CI) 1.062-4.643; P = 0.02; and type IV: adjusted OR 3.169; 95% CI 1.058-6.657; P = 0.002]. The results revealed that P. gingivalis types II and IV are related to LAA SEC severity among AF patients who receive appropriate anticoagulation therapy.

Clinical characteristics and outcomes in patients with echocardiographic left ventricular spontaneous echo contrast

BACKGROUND

Spontaneous echo contrast (SEC) is a known precursor to thrombus formation and thromboembolic events. This study aims to demonstrate the clinical characteristics and outcomes of patients with left ventricular spontaneous echo contrast (LV-SEC).

METHODS

Patients with consecutive echocardiogram performed from October 2009 to September 2019 were enrolled in this retrospective, single-center study. Those with LV-SEC were included, while patients complicated by left ventricular thrombus, with history of infective endocarditis, prosthetic valves, or lost to follow-up were excluded. The clinical endpoint was 1-year thromboembolic events (i.e. stroke and peripheral embolism).

RESULTS

Among 417 patients (mean age 63.5 ± 14.7 years; 86.8% men) with LV-SEC, the incidence of 1-year embolism was 12.9%. In multivariate Cox proportional hazard model, significant risk factors for thromboembolic event were age [hazard ratio (HR) = 1.022, 95% confidence interval (CI): 1.000-1.045], atrial fibrillation (AF) (HR = 2.292, 95% CI: 1.237-4.244), hemoglobin (HR = 1.032, 95% CI: 1.017-1.047), left ventricular ejection fraction (LVEF) (HR = 1.021, 95% CI: 1.002-1.041), and anticoagulant therapy (HR = 0.310, 95% CI: 0.168-0.572). For patients with repeated measurements for echocardiography, D-dimer (HR = 1.137, 95% CI: 1.051-1.231), and △LVEF (HR = 0.961, 95% CI: 0.928-0.996) were independently associated with the persistent LV-SEC.

CONCLUSION

The present study reported a high incidence of 1-year thromboembolic event in patients with LV-SEC. Age, AF, hemoglobin, LVEF were independent risk factors for 1-year embolism and a reduced risk of embolism was observed among patients with anticoagulation therapy. Additionally, D-dimer and △LVEF are independently associated with the persistent LV-SEC.

The prevalence, predictors, and outcomes of spontaneous echocardiographic contrast or left ventricular thrombus in patients with HFrEF

AIMS

This study aimed to determine prevalence, predictors, and association with ischaemic stroke risk of spontaneous echocardiographic contrast (SEC) or left ventricular thrombus (LVT) in patients with heart failure with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Clinical, echocardiographic, and follow-up data from January 2009 through February 2019 were retrospectively extracted from electronic medical records of patients with heart failure with left ventricular ejection fraction < 40% by echocardiography on admission, with follow-up to February 2020. Of 9485 consecutive patients with HFrEF, 123 (1.3%) presented LVT and 331 (3.5%) presented SEC. Patients with vs. those without SEC/LVT had larger left ventricular end-diastolic volume (199.5 ± 77.7 vs. 165.8 ± 61.3 mL, P < 0.001), lower left ventricular ejection fractions (29.5 ± 7.0% vs. 33.7 ± 5.5%, P < 0.001), and more often ischaemic cardiomyopathy, apical aneurysm, chronic kidney diseases, and smoking habit. In Cox regression analysis, SEC and LVT were independent predictors for ischaemic stroke occurrence [hazard ratio (HR) = 2.40, 95% confidence interval (CI): 1.74-3.31; HR = 4.52, 95% CI: 2.77-7.40, both P < 0.001]. In patients with those without SEC or LVT, stroke risk was higher among those not on anticoagulants (HR = 2.55, 95% CI: 1.85-3.53; HR = 4.71, 95% CI: 2.84-7.81, both P < 0.001), but similar among those on anticoagulants (P > 0.05). In patients with sinus rhythm, the associations between SEC/LVT and ischaemic stroke persist with HRs of 2.57 (95% CI: 1.69-3.92) and 5.74 (95% CI: 3.38-9.75).

CONCLUSIONS

In patients with HFrEF, SEC was not uncommon and increased risk of ischaemic stroke as well as LVT. Anticoagulants could play a role in the reduction of stroke risk, suggesting that patients with SEC/LVT, even those in sinus rhythm, would benefit from systemic anticoagulation treatment.

A novel risk model to predict first-ever ischemic stroke in heart failure with reduced ejection fraction

Patients with heart failure are at increased risk for ischemic stroke. We aim to develop a more accurate stroke risk prediction tools identify high-risk patients with heart failure with reduced ejection fraction (HFrEF). Patient data were extracted retrospectively from the electronic medical database between January 2009 and February 2019. Univariate and multivariate Cox regression analysis were performed to identify independent predictors, which were utilized to construct a nomogram for predicting ischemic stroke. AUROC analysis was used to compare the prognostic value between the new risk score and CHADS2/CHA2DS2-VASc scores. In 6087 patients with HFrEF, the risk of first-ever ischemic stroke was 5.8% events/pts-years (n=468) during 8007.2 person-years follow-up. A nomogram constructed by integrating 6 variables, including age, atrial fibrillation (AF), deep vein thrombosis (DVT), d-dimer, anticoagulant use and spontaneous echocardiographic contrast (SEC)/left ventricular thrombus (LVT), exhibited a greater area under the curve of 0.727, 0.728 and 0.714 than that by CHADS2 score (0.515, 0.522 and 0.540), and by CHA2DS2-VASc score (0.547, 0.553 and 0.562) for predicting first-ever ischemic stroke at hospitalization, 30-day and 6-month follow-up (all p<0.001). This novel stroke risk score performed better than existing CHADS2/ CHA2DS2-VASc scores and showed improvement in predicting first-ever ischemic stroke in HFrEF patients.

Blood flow volume of left atrial appendage measured by magnetic resonance imaging is improved after radiofrequency catheter ablation of atrial fibrillation

INTRODUCTION

Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients. Velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the association between radiofrequency catheter ablation (RFCA) and LAA hemodynamics measured by MRI.

METHODS AND RESULTS

Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.93 ± 32.92 and 72.00 ± 34.82 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 14.63 ± 40.67 vs. 30.03 ± 35.37; p < .001) and low pre-RFCA VENC-MRI (∆VENC-MRI = 17.19 ± 38.35 vs. 50.35 ± 29.12; p < .001) had significantly higher improvement in VENC-MRI. Those who experienced late recurrence before post-RFCA MRI had significantly less improvement in LAA flow volume (∆VENC-MRI = 15.55 ± 41.41 vs. 26.18 ± 36.77; p = .011). Late recurrence and pre-RFCA VENC-MRI were significantly associated with ∆VENC-MRI after adjusting covariates. Patients who were AF before RFCA but maintained sinus rhythm after RFCA showed greatest improvement in VENC-MRI.

CONCLUSION

Effective rhythm control through RFCA can be associated with significant improvement in LAA hemodynamics. Low pre-RFCA VENC-MRI and absence of late recurrence were associated with greater improvement in LAA hemodynamics.

Therapeutic plasma exchange for COVID-19-associated hyperviscosity

Background

Recent data suggests an association between blood hyperviscosity and both propensity for thrombosis and disease severity in patients with COVID‐19. This raises the possibility that increased viscosity may contribute to endothelial damage and multiorgan failure in COVID‐19, and that therapeutic plasma exchange (TPE) to decrease viscosity may improve patient outcomes.

Here we sought to share our experience using TPE in the first 6 patients treated for COVID‐19‐associated hyperviscosity.

Study Design and Methods

Six critically ill COVID‐19 patients with plasma viscosity levels ranging from 2.6 to 4.2 centipoise (cP; normal range, 1.4‐1.8 cP) underwent daily TPE for 2‐3 treatments.

Results

TPE decreased plasma viscosity in all six patients (Pre‐TPE median 3.75 cP, range 2.6‐4.2 cP; Post‐TPE median 1.6 cP, range 1.5‐1.9 cP). TPE also decreased fibrinogen levels in all five patients for whom results were available (Pre‐TPE median 739 mg/dL, range 601‐1188 mg/dL; Post‐TPE median 359 mg/dL, range 235‐461 mg/dL); D‐dimer levels in all six patients (Pre‐TPE median 5921 ng/mL, range 1134‐60 000 ng/mL; Post‐TPE median 4893 ng/mL, range 620‐7518 ng/mL); and CRP levels in five of six patients (Pre‐TPE median 292 mg/L, range 136‐329 mg/L; Post‐TPE median 84 mg/L, range 31‐211 mg/L). While the two sickest patients died, significant improvement in clinical status was observed in four of six patients shortly after TPE.

Conclusions

This series demonstrates the utility of TPE to rapidly correct increased blood viscosity in patients with COVID‐19‐associated hyperviscosity. Large randomized trials are needed to determine whether TPE may improve clinical outcomes for patients with COVID‐19.

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.

Development of Spontaneous Echocardiographic Contrast After Transarterial Occlusion of a Patent Ductus Arteriosus in an Adult Dog With Concurrent Pulmonary Hypertension

An 8-year-old intact female Chihuahua was presented for evaluation and possible occlusion of a previously diagnosed patent ductus arteriosus (PDA). Transthoracic echocardiography revealed left ventricular and left atrial enlargement, enlargement of the main pulmonary artery, and a PDA with bidirectional shunting. Tricuspid regurgitant velocities suggested moderate pulmonary hypertension. The PDA was occluded with an Amplatz® Canine Duct Occluder using a transarterial approach on the following day. No immediate complications were observed other than an acute decrease in left ventricular systolic function. One day after the PDA occlusion transthoracic echocardiography revealed no residual ductal flow, but there was spontaneous echocardiographic contrast in the left ventricle. The patient was discharged with sildenafil, pimobendan, and clopidogrel. Five weeks later when the patient was presented for a recheck examination, the previously documented spontaneous echocardiographic contrast was no longer present. Finding spontaneous echocardiographic contrast in the dog has not previously been reported in association with PDA occlusion.

Implication of d-dimer in rheumatic severe mitral stenosis – A tertiary centre study

Background

In rheumatic mitral stenosis (MS), left atrial (LA) thrombus and LA spontaneous echo contrast (LA SEC) reflect hypercoagulability. The study focuses on whether D-dimer levels predict the existence of LA thrombus and SEC in patients with severe MS.

Methods

95 consecutive patients with severe MS referred for transesophageal echocardiogram (TEE) between July 2011 and March 2012 to evaluate LA thrombus prior to balloon mitral valvotomy (BMV) were included in the study. D-Dimer levels in these patients were observed.

Results

Out of the 95 patients, 15 (15.8%) had LA thrombus and 52 patients had LA SEC (54.7%). Any correlation between D-Dimer levels and existence (or non-existence) of LA thrombus was not noticed from the receiver operating characteristics (ROC) curve with an area of .535. For patients with LA SEC, the D-Dimer levels were found to be considerably higher (776 ± 866 μg/L vs. 294 ± 331 μg/L, p = .001). An ideal cut-off level of 393 μg/L for diagnosing LA SEC was illustrated by the ROC curve with a sensitivity of 63.4%, specificity of 83.72%, positive predictive value of 82.5% and a negative predictive value of 65.45%.

Conclusions

D-dimer levels were not representative of the presence or absence of LA thrombus in patients with severe MS. Nonetheless, this study demonstrated the substantial link between D-Dimer level and LA SEC. If a D-Dimer level of 400 μg/L or higher is taken as positive, it has high specificity and positive predictive value for diagnosing LA SEC.

Cats with thermal burn injuries from California wildfires show echocardiographic evidence of myocardial thickening and intracardiac thrombi

Recent increases in the prevalence and severity of wildfires in some regions have resulted in an increased frequency of veterinary burn patients. Few studies exist regarding diagnostics and management of burn wounds in veterinary patients and current knowledge is extrapolated from human literature and research models. Post-burn cardiac injury is a common finding and predictor of mortality in human patients and echocardiography is an important tool in monitoring response to therapy and predicting outcome. We describe the notable findings from cats naturally exposed to California wildfires in 2017 and 2018. Domestic cats (n = 51) sustaining burn injuries from the Tubbs (2017) and Camp (2018) wildfires were prospectively enrolled and serial echocardiograms and cardiac troponin I evaluations were performed. Echocardiograms of affected cats revealed a high prevalence of myocardial thickening (18/51) and spontaneous echocardiographic contrast and thrombi formation (16/51). Forty-two cats survived to discharge and 6 died or were euthanized due to a possible cardiac cause. For the first time, we describe cardiovascular and coagulation effects of thermal burn and smoke inhalation in cats. Further studies in veterinary burn victims are warranted and serve as a translational research opportunity for uncovering novel disease mechanisms and therapies.

Cats with thermal burn injuries from California wildfires show echocardiographic evidence of myocardial thickening and intracardiac thrombi

Recent increases in the prevalence and severity of wildfires in some regions have resulted in an increased frequency of veterinary burn patients. Few studies exist regarding diagnostics and management of burn wounds in veterinary patients and current knowledge is extrapolated from human literature and research models. Post-burn cardiac injury is a common finding and predictor of mortality in human patients and echocardiography is an important tool in monitoring response to therapy and predicting outcome. We describe the notable findings from cats naturally exposed to California wildfires in 2017 and 2018. Domestic cats (n = 51) sustaining burn injuries from the Tubbs (2017) and Camp (2018) wildfires were prospectively enrolled and serial echocardiograms and cardiac troponin I evaluations were performed. Echocardiograms of affected cats revealed a high prevalence of myocardial thickening (18/51) and spontaneous echocardiographic contrast and thrombi formation (16/51). Forty-two cats survived to discharge and 6 died or were euthanized due to a possible cardiac cause. For the first time, we describe cardiovascular and coagulation effects of thermal burn and smoke inhalation in cats. Further studies in veterinary burn victims are warranted and serve as a translational research opportunity for uncovering novel disease mechanisms and therapies.

Spontaneous intracardiac microcavitations in a patient with a colonic carcinoma

Intracardiac microcavitations consist of airy microbubbles. They are typically found in patients with an intravascular line or device, mechanical heart valves or in decompression sickness. We report a case of a patient in mid-70s who was admitted due to weakness in both legs, left-thoracic pain and fever. Despite the lack of any of the risk factors mentioned above, spontaneous microcavitations were detected in the right sided cardiac cavities. After the detection of liver lesions suspicious for a metastatic disease, a colonoscopy was performed. An ulcerated colonic carcinoma at the ileocoecal valve was diagnosed and highly suspicious for being the entry port of the microcavitations. This unusual presentation of microcavitations together with a colonic neoplasia leads to hypotheses about the journey of the microbubbles from the ascending colon into the right heart. Gastrointestinal tumours are described as being the causes of microbubbles. Translocation of microbubbles through hepatopulmonary shunting are described in the context of locally applied particles of similar size during radioembolisation. A thorough aetiological workup is of importance since the underlying cause is potentially dangerous due to its own nature of disease and due the complications of the microcavitations such as paradoxical emboli or pulmonary sequelae.

Diagnosis and Management of Left Atrium Appendage Thrombosis in Atrial Fibrillation Patients Undergoing Cardioversion

Atrial fibrillation is the most common cardiac arrhythmia and is associated with an increased risk of stroke and thromboembolic complications. A rhythm control strategy with both electrical and pharmacological cardioversion is recommended for patients with symptomatic atrial fibrillation. Anticoagulant therapy for 3–4 weeks prior to cardioversion is recommended in order to avoid thromboembolic events deriving from restoring sinus rhythm. Transesophageal echocardiography has a pivotal role in this setting, excluding the presence of left atrial appendage thrombus before cardioversion. The aim of this review is to discuss the epidemiology and risk factors for left atrial appendage thrombosis, the role of echocardiography in the decision making before cardioversion, and the efficacy of different anticoagulant regimens on the detection and treatment of left atrial appendage thrombosis.

Stroke Risk in Atrial Fibrillation: Beyond the CHA2DS2-VASc Score

PURPOSE OF REVIEW

Stroke prevention is the cornerstone of atrial fibrillation (AF) management and the anticoagulation decision is currently based on CHA₂DS₂-VASc risk score. We discuss several novel risk factors besides those included in CHA₂DS₂-VASc score and alternative models for stroke prediction.

RECENT FINDINGS

Several clinical markers including obstructive sleep apnea and renal failure, laboratory markers like brain natriuretic peptide, imaging criteria including left atrial appendage morphology, spontaneous echo contrast, and coronary artery calcium score may predict stroke in AF patients. Addition of African American ethnicity to CHA₂DS₂-VASc score also improves stroke prediction in AF. Finally, novel models including TIMI-AF score, ATRIA score, and GARFIELD-AF scores have potential roles in risk stratification for stroke. While CHA₂DS₂-VASc score is the currently recommended risk stratification model for stroke prediction in AF, use of additional clinical, laboratory, imaging markers, ethnicity, and novel stroke prediction models may further assist in decision to anticoagulate the AF patient for stroke prevention.

Left atrial spontaneous echo contrast: relationship with clinical and echocardiographic parameters

Spontaneous echo contrast (SEC) indicates blood stasis in cardiac chambers and major vessels, and is a known precursor of thrombus formation. Transesophageal echocardiography plays a pivotal role in detecting and grading SEC in the left atrial (LA) cavity. Assessing LA SEC can identify patients at increased risk for thromboembolic events. LA SEC also develops in patients who have sinus rhythm, especially in those with heart failure. Detection of LA SEC is not uncommon in subjects who have multiple cardiovascular comorbidities, although mechanisms behind this association are not fully understood. In patients with atrial fibrillation, the role of mitral regurgitation in counteracting LA SEC and subsequent thromboembolism is controversial. Moreover, alterations of blood coagulability and elevated levels of certain biological markers in the blood contribute to occurrence of LA SEC. This review describes the pathogenesis and assessment of SEC, in addition to the relationship between LA SEC and clinical, biological and echocardiographic parameters.

Risk Factors for Ischemic Stroke in Atrial Fibrillation Patients Undergoing Radiofrequency Catheter Ablation

Ischemic stroke after radiofrequency catheter ablation (RFCA) in atrial fibrillation (AF) patients is a great challenge for electrophysiologists. We performed this retrospective study to evaluate clinical and echocardiographic characteristics associated with increased risk of ischemic stroke following RFCA. A total of 2,352 consecutive patients with AF who underwent first-time RFCA were analyzed. Among 10,023 patient*year follow up, ischemic stroke occurred in 49 patients (0.49% per year). Late recurrence after last RFCA was significantly associated with ischemic stroke (3.8% vs. 12.9%, p < 0.001). Old age (≥60 years old) (3.2% vs. 15.4%, p = 0.001), non-paroxysmal AF (hazard ratio = 1.91, p = 0.024), left atrium (LA) size ≥45.0 mm (6.6% vs. 11.7%, p < 0.001), E over E’ ≥10 (4.3% vs. 20.1%, p < 0.001), dense spontaneous echo contrast (SEC) (5.2% vs. 19.0%, p = 0.006), and decreased left atrial appendage (LAA) flow velocity (≤40 cm/sec) (4.1% vs. 10.8%, p < 0.001) were also associated with increased risk of ischemic stroke. The REVEEAL score derived from the risk factors identified in this study was superior to CHA₂DS₂-VASc score (p < 0.001) for the prediction of ischemic stroke. In conclusion, the risk factors for ischemic stroke in post-RFCA AF patients are not identical to RFCA naive AF patients and different approach to stratify the risk of ischemic stroke is needed.

Relationship between presence of spontaneous echo contrast and platelet-to-lymphocyte ratio in patients with mitral stenosis

BACKGROUND

Left atrial spontaneous echo contrast (SEC) is an existence of smoke-like echoes with a typical swirling motion of blood in left atrial cavity or appendage, and it is known to be a marker of prothrombotic state. Previous studies have revealed that there is an association between prothrombotic state and the platelet-to-lymphocyte ratio (PLR). Thus, we aimed to investigate the association between the presence of SEC and PLR in patients with mitral stenosis (MS).

METHODS

A total of 306 consecutive patients with MS were enrolled in the study. Transoesophageal echocardiography was made to assess the SEC for all patients. Recruited patients were divided into two groups according to the formation of SEC in the left atrium. Complete blood counting parameters, biochemical tests and high-sensitive C-reactive protein (Hs-CRP) levels were measured.

RESULTS

There were 182 patients (mean age 42.7 ± 11.9 and 78% female) in the SEC (-) group, and 124 patients (mean age 45.3 ± 10.5 and 68% female) in the SEC (+) group. Hs-CRP levels (3.9 ± 1.9 vs 5.1 ± 3.6, P < 0.001) were significantly different between the two groups. PLR (143.4 ± 77.7 vs 180.6 ± 108.7, P < 0.001) was significantly higher in the SEC (+) group. ROC curve analysis, PRL ≥123 had 71% sensitivity and 52% specificity in predicting SEC in patients with MS.

CONCLUSION

Platelet-to-lymphocyte ratio is an inexpensive and easily calculated biomarker, which is useful to predict left atrial SEC in patients with mitral stenosis.

Different influence of cardiac hemodynamics on thromboembolic events in patients with paroxysmal and non-paroxysmal atrial fibrillation

Blood stasis in left atrium (LA) or LA appendage (LAA) is thought to be the main cause of thrombus formation and systemic embolism in atrial fibrillation (AF) patients. Paroxysmal and non-paroxysmal AF differ significantly in various aspects. Impact of cardiac hemodynamics on systemic embolism might also differ between the 2 distinct AF entities. This study was performed to evaluate the influence of cardiac hemodynamics on systemic embolism in both paroxysmal and non-paroxysmal AF. Consecutive AF patients undergoing radiofrequency catheter ablation (RFCA) in Korea University Medical Center Anam Hospital between June 1998 and February 2018 were analyzed. Among 2,801 patients who underwent first-time RFCA, a total of 231 patients had either previous ischemic stroke, transient ischemic attack, or arterial embolism. In paroxysmal AF, LA diameter, LA volume (measured with magnetic resonance imaging), left ventricular (LV) ejection fraction, E/e’, LAA flow velocity, and prevalence of spontaneous echocontrast (SEC) and dense SEC were significantly different between patients with and without thromboembolic events. However, only E/e’ was different between patients with and without thromboembolic events in non-paroxysmal AF. The influence of LA diameter, LA volume, LV EF, LAA flow velocity, and dense SEC on thromboembolic events was significantly moderated by the type of AF. In conclusion, paroxysmal and non-paroxysmal AF might have a different mechanism responsible for thrombus formation and consequent embolic events. Relative contribution of hemodynamic parameters and other factors such as atrial myopathy to thromboembolic events in paroxysmal versus non-paroxysmal AF needs further evaluation.

Risk Assessment of Stroke in Patients with Atrial Fibrillation: Current Shortcomings and Future Directions

Atrial fibrillation is a well-known risk factor for cardioembolic stroke; a number of risk stratification scoring systems have been developed to help differentiate which patients would stand to benefit from anticoagulation. However, these scoring systems cannot be utilized in patients whose atrial fibrillation has not been diagnosed. As implantable cardiac monitors become more prevalent, it becomes possible to identify occult, subclinical atrial fibrillation. With this data, it is also possible to examine the relationship between episodes of paroxysmal atrial fibrillation and thromboembolism and the total burden of paroxysmal atrial fibrillation and thromboembolic risk. The data gleaned from these devices provides insight and raises questions regarding the underlying mechanism of thromboembolism in atrial fibrillation, and in doing so, exposes shortcomings in the present clinical use of current risk scoring systems, specifically, the inability to account for atrial fibrillation burden and to apply scores at all in subclinical atrial fibrillation.

A Rare Case of Dense Spontaneous Echo Contrast within Inferior Vena Cava

A 33-year-old gentleman was examined because of fatigue and progressive right heart failure. A striking finding in his echocardiogram was intense and slow-moving dense echo contrast in the inferior vena cava (IVC). Cardiac catheterization revealed constrictive pericarditis, and pericardiectomy was performed. Postoperatively spontaneous echo contrast in IVC have resolved. This case helps explain the origin of spontaneous IVC contrast.

Impact of dense "smoke" detected on transesophageal echocardiography on stroke risk in patients with atrial fibrillation undergoing catheter ablation

BACKGROUND

Spontaneous echocardiographic contrast ("smoke") within the left atrial cavity on transesophageal echocardiography (TEE) suggests low blood flow velocities in the heart that may lead to thromboembolic (TE) events.

OBJECTIVE

The purpose of this study was to evaluate the risk of TE events in the periprocedural period and at long-term follow-up in atrial fibrillation (AF) patients having dense smoke on preprocedural TEE.

METHODS

A total of 2511 patients undergoing AF ablation were included in this analysis. They were classified as group 1 (dense smoke detected on TEE at baseline; n = 234) and group 2 (no smoke on baseline TEE; n = 2277). Patients were followed up for TE events, which included both stroke and transient ischemic attacks (TIAs). In order to attenuate the observed imbalance in baseline covariates between the study groups, a propensity score matching technique was used (covariates were age, sex, AF type, diabetes, and CHADS₂VASc score).

RESULTS

In the periprocedural period, no TE events were reported in group 1 and 3 events (0.13%) were reported in group 2. At follow-up of 6.62 ± 2.01 years, 6 (2.6%) TE complications (2 TIA, 4 stroke) occurred in group 1 and 16 (0.70%) TE complications (6 TIA, 10 stroke) in group 2 (P = .004). In the propensity-matched population, 6 (2.56%) TE complications occurred in group 1 and 1 (0.2%) in group 2 (P = .007).

CONCLUSION

In our study population, the presence of dense left atrial smoke did not show any correlation with periprocedural TE events in patients undergoing catheter ablation with uninterrupted anticoagulation. However, significant association was observed with late stroke/TIA, irrespective of CHA₂DS₂-VASc score.

Predictive value of red cell distribution width on left atrial thrombus or left atrial spontaneous echo contrast in patients with non-valvular atrial fibrillation

OBJECTIVE

To evaluate the predictive value of red cell distribution width (RDW) on left atrial thrombus (LAT) or left atrial spontaneous echo contrast (LASEC) in patients with non-valvular atrial fibrillation (AF).

METHODS

We reviewed 692 patients who were diagnosed as non-valvular AF and underwent transesophageal echocardiography (TEE) in Guangdong Cardiovascular Institute from April 2014 to December 2015. The baseline clinical characteristics, laboratory test of blood routine, electrocardiograph measurements were analyzed.

RESULTS

Eighty-four patients were examined with LAT/LASEC under TEE. The mean RDW level was significantly higher in LAT/LASEC patients compared with the non-LAT/LASEC patients (13.59% ± 1.07% vs. 14.34% ± 1.34%; P < 0.001). Receiver-operating characteristic curve analysis was performed and indicated the best RDW cut point was 13.16%. Furthermore, multivariate logistic regression analysis indicated that RDW level > 13.16% could be an independent risk factor for LAT/LASEC in patients with AF.

CONCLUSION

Elevated RDW level is associated with the presence of LAT/LASEC and could be with moderate predictive value for LAT/LASEC in patients with non-valvular AF.

Different Responses of Left Atrium and Left Atrial Appendage to Radiofrequency Catheter Ablation of Atrial Fibrillation: a Follow Up MRI study

Atrial fibrillation (AF) is known to cause adverse remodeling of left atrium (LA). Radiofrequency catheter ablation (RFCA) of AF is associated with decrease in LA volume. However, the impact of RFCA on left atrial appendage (LAA) volume and hemodynamic function is not fully understood. We analyzed 123 patients who underwent cardiac magnetic resonance imaging (MRI) evaluation before and after RFCA in Korea University Anam Hospital. LA and LAA volume were measured before and after RFCA based on cardiac MRI. Baseline LA volume was 99.5 ± 38.4 cm³ and decreased to 74.6 ± 28.5 cm³ after RFCA (p < 0.001). LA diameter measured with transthoracic echocardiography was also decreased after RFCA (43.3 ± 6.2 mm at baseline and 39.9 ± 5.9 mm at follow up; p < 0.001). However, LAA volume was significantly increased after RFCA (19.4 ± 8.5 cm³ at baseline and 23.7 ± 13.3 cm³ at follow up; p < 0.001). Total ablation time and additional substrate modification was associated with change in LA volume. After RFCA, average LAA velocity measured by transesophageal echocardiography was increased to 51.0 cm/sec from 41.1 cm/sec (p < 0.001). In conclusion, LAA volume was increased after RFCA in contrast to LA volume. Our data raise a concern about worsening hemodynamics of LA and LAA following RFCA and long term clinical significance of enlarged LAA after RFCA needs further evaluation.