Assessment of Left Atrial Appendage Morphology and Function in Patients with Non-valvular Paroxysmal Atrial Fibrillation with Different Rhythms Using Real-Time 3D Transesophageal Echocardiography

Correlation between LAA Morphological Features and Computational Fluid Dynamics Analysis for Non-Valvular Atrial Fibrillation Patients

The left atrial appendage (LAA) is a complex cardiovascular structure which can yield to thrombi formation in patients with non-valvular atrial fibrillation (AF). The study of LAA fluid dynamics together with morphological features should be investigated in order to evaluate the possible connection of geometrical and hemodynamics indices with the stroke risk. To reach this goal, we conducted a morphological analysis of four different LAA shapes considering their variation during the cardiac cycle and computational fluid dynamics (CFD) simulations in AF conditions were carried out. The analysis of main geometrical LAA parameters showed a huger ostium and a reduced motility for the cauliflower and cactus shapes, as well as a lower velocity values from the CFD analysis. Such findings are in line with literature and highlight the importance of coupling dynamics imaging data with CFD calculations for providing information not available at clinical level.

Morphologic and functional features of left atrial appendage in Iranian population: an echocardiographic study

Introduction: Cardioembolic events are accompanied by left atrial appendage (LAA) in patients suffering from atrial fibrillation (AF); therefore, the LAA closure is implemented as a preventive strategy. The detection of LAA morphologies and function is a paramount step before establishing the LAA closure. Herein, we sought to determine the morphologic features of the LAA in an Iranian population using echocardiographic evaluation.

Methods: Seventy-two near-normal heart patients were investigated by conducting a cross-sectional study. All patients were examined using the 2-dimensional and 3-dimensional transesophageal echocardiography (2D- and 3D-TEE) method. The anatomical features and functions of LAA were examined. All images were stored and analyzed offline.

Results: The patients’ mean age was 39 ± 15.5 year and 33 (45.8%) were female. The most frequent shape of LAA was wind sock . More LAA lobes was observed in patients with AF compared to those with NSR. In comparison with AF group, the NSR had higher LAA flow velocity (P < 0.01). The paroxysmal AF had greater LAA flow velocity and LAA ejection fraction in comparison with the chronic AF (39 ± 19 vs. 75 ± 22, P < 0.01; and 49±4 vs. 72±14, P < 0.003; respectively). The paroxysmal AF had smaller systolic LAA orifice area in comparison with the chronic AF (P < 0.02).

Conclusion: The morphologic features of LAA in Iranian population were within the range of other studies and LAA length and orifice diameters in 2D- and 3D-TEE were consistent. In addition, AF influenced the morphologies and functions of LAA compared to sinus rhythm.

Simultaneous Functional and Morphological Assessment of Left Atrial Appendage by 3D Virtual Models

Purpose

The left atrial appendage (LAA) is responsible for thrombus formation in patients with atrial fibrillation. The evaluation of both LAA function and morphology is crucial for the patient characterization and the preprocedural planning of LAA closure intervention. Despite the availability of 3D imaging modalities, the current standard image analysis is based on manual delineation of the LAA contours on 2D views.

Methods

In this study, a comprehensive approach based on a full 3D analysis of the tomographic dataset by surface extraction and processing (3D-S) is presented. The proposed method allows extracting functional and morphologic information in the entire cardiac cycle by minimalizing manual user interaction. The proposed methodology has been validated on ten computer tomography datasets.

Results

The proposed 3D-S method was feasible in all cases. Reproducibility was improved with respect to the reference 2D manual procedure (2D-S) (coefficient of variation 2.9 vs. 4.1% for diastolic ostium area; 3.8 vs. 6.1% for systolic ostium area; 2.4 vs. 5.3% for diastolic LAA volume; 2.7 vs. 5.9% for systolic LAA volume; and 7.7 vs. 17.1% for LAA ejection fraction). No significant differences were found between 2D-S and 3D-S measurements.

Conclusions

In this study, we introduced a fully 3D approach for LAA characterization, allowing the simultaneous assessment of LAA function and geometry. The proposed approach could be used to improve the patient selection and the best sizing of the device for LAA closure and to allow a patient-specific 3D printing.

Left atrial appendage morphology and relative contrast agent concentration in patients undergoing coronary artery CTA

AIM

To evaluate whether certain morphological features of the left atrial appendage (LAA) would influence the LAA/ascending aorta (AA) radiodensity ratio, as a reflection of the blood flow conditions in the LAA.

MATERIALS AND METHODS

Eight-hundred and eight consecutive patients undergoing computed tomography angiography (CCTA) were evaluated. Of these, 749 had no history of atrial fibrillation and none had suffered acute stroke. The LAA/AA radiodensity ratio, and the length, lobe number, and morphological classification of LAAs were assessed.

RESULTS

The distribution of morphological classes for LAAs were: windsock 62.3%, cactus 18.6%, chicken wing 10.0%, and cauliflower 9.2%. The mean LAA/AA radiodensity ratio was 0.87±0.14 (range 0.22-1.44). Female gender (p=0.001), elevated body mass index (BMI; r=-0.129; p=0.003), and diabetes (p=0.03) were associated with lower LAA/AA radiodensity ratios, while heart failure (p=0.017), significant coronary artery stenosis (p=0.010), and LAAs with multiple lobes (p=0.018), exhibited higher LAA/AA radiodensity ratios. Multiple regression analysis revealed that a short one-lobed cauliflower morphology was an independent predictor (p=0.007) of a decreased LAA/AA radiodensity ratio.

CONCLUSION

A decline in the LAA/AA radiodensity ratio may reflect decreased blood flow in the LAA, paralleling spontaneous echo contrast in transoesophageal echocardiography. Thus, CCTA might be of value in recognising LAA structures that predispose to decreased blood flow.

Evaluation of the left atrial appendage by real time three-dimensional transesophageal echocardiography online

OBJECTIVE

The objective of this study was to evaluate the feasibility of online real time three-dimensional transesophageal echocardiography (RT3DTEE) in the measurement of left atrial appendage (LAA) orifice size. We also analyzed the correlation between LAA ejection fraction (EF) and its peak empty velocity (PEV).

METHODS

There were 91 subjects enrolled in this study, with 46 patients with AF and 45 individuals with sinus rhythm (SR). RT3DTEE was performed by four methods including iSlice and iCrop online and QLAB software 3DQ and GI-3DQ off-line which were used to measure LAA orifice area, long diameter, short diameter, depth in the largest LAA, and number of LAA lobes. These LAA parameters achieved by the four methods were compared, respectively. GI-3DQ off-line was used to measure LAA end-diastolic and end-systolic volumes to calculate EF of LAA. Two-dimensional (2D) TEE was applied to measure PEV of LAA. The correlation between EF and PEV was analyzed.

RESULTS

There were no significant differences in all LAA parameters between any two RT3DTEE methods (All P > .05). There was a significant and positive correlation between PEV and EF (r = .423, P = .000). There were statistical differences in LAA EF and PEV between patients with AF and SR individuals (0.38 ± 0.12 vs 0.61 ± 0.07, 35.7 ± 12.1 vs 49.5 ± 10.0 cm/s, P = .000).

CONCLUSION

Using online RT3DTEE for measuring LAA orifice size is feasible, and online RT3DTEE is more convenient than offline RT3DTEE. EF is positively correlated with PEV. LAA function is significantly decreased in patients with AF.