Assessment of the left atrial appendage mechanical function by three-dimensional echocardiography

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.

Evaluation of left atrial appendage function and thrombi in patients with atrial fibrillation: from transthoracic to real time 3D transesophageal echocardiography

The detection of embolic sources in patients with atrial fibrillation (AF) is important to guide anticoagulant therapy. Two-dimensional transesophageal echocardiography (TEE) is the gold standard to study left atrial appendage (LAA) anatomy and morphology, despite some false-positive diagnosis. We hypothesized that real time 3D TEE (RT3DTEE) is superior to 2DTEE in detecting and/or excluding LAA thrombi. We studied 93 patients with non-valvular AF (60 males, age = 67.1 ± 14.2 years) referred for electric cardioversion with transthoracic, 2DTEE and RT3DTEE. Before cardioversion, TTE allowed a confident measurement of emptying velocity of LAA (LAAeV) only in 59/93 patients (63%). On the contrary a good quality TEE LAAeV was obtained in all patients with 49/93 (53%) dysfunctional LAA (LAAeV < 40 cm/s). A subgroup of 5 patients (7.2% of the 69 effective cardioversion) presented a persistent dysfunction after cardioversion (with LAAeV values of <40 cm/s on the TEE post-CV). TEE allowed to observe a bilobed shape in 45 patients (48.4%) and three lobes in 22 patients (23.7%). In addition, besides to several additional findings, 2DTEE managed to detect thrombi with certainty in 8/93 patients (8.6%). In other 5 cases with diagnostic doubts for thrombi with 2DTEE (5/93 patients: 5.4%), the addition of the RT3DTEE mode allowed to discriminate with certainty the presence of just pectinate muscles in 4 patients RT3DTEE in patients with AF at risk of embolism is feasible, accurate and showed an additional diagnostic capability in the differential diagnosis of selected cases with suspected LAA thrombi.

Rotational method simplifies 3-dimensional measurement of left atrial appendage dimensions during transesophageal echocardiography

Background

Not all echo laboratories have the capability of measuring direct online 3D images, but do have the capability of turning 3D images into 2D ones “online” for bedside measurements. Thus, we hypothesized that a simple and rapid rotation of the sagittal view (green box, x-plane) that shows all needed left atrial appendage (LAA) number of lobes, orifice area, maximal and minimal diameters and depth parameters on the 3D transesophageal echocardiography (3DTEE) image and LAA measurements after turning the images into 2D (Rotational 3DTEE/“Yosefy Rotation”) is as accurate as the direct measurement on real-time-3D image (RT3DTEE).

Methods

We prospectively studied 41 consecutive patients who underwent a routine TEE exam, using QLAB 10 Application on EPIQ7 and IE33 3D-Echo machine (BORTHEL Phillips) between 01/2013 and 12/2015. All patients underwent 64-slice CT before pulmonary vein isolation or for workup of pulmonary embolism. LAA measurements were compared between RT3DTEE and Rotational 3DTEE versus CT.

Results

Rotational 3DTEE measurements of LAA were not statistically different from RT3DTEE and from CT regarding: number of lobes (1.6 ± 0.7, 1.6 ± 0.6, and 1.4 ± 0.6, respectively, p = NS for all); internal area of orifice (3.1 ± 0.6, 3.0 ± 0.7, and 3.3 ± 1.5 cm², respectively, p = NS for all); maximal LAA diameter (24.8 ± 4.5, 24.6 ± 5.0, and 24.9 ± 5.8 mm, respectively, p = NS for all); minimal LAA diameter (16.4 ± 3.4, 16.7 ± 3.3, and 17.0 ± 4.4 mm, respectively, p = NS for all), and LAA depth (20.0 ± 2.1, 19.8 ± 2.2, and 21.7 ± 6.9 mm, respectively, p = NS for all).

Conclusion

Rotational 3DTEE method for assessing LAA is a simple, rapid and feasible method that has accuracy similar to that of RT3DTEE and CT. Thus, rotational 3DTEE (“Yosefy rotation”) may facilitate LAA closure procedure by choosing the appropriate device size.

Cardioembolic stroke in atrial fibrillation-rationale for preventive closure of the left atrial appendage

Atrial fibrillation is the most common cardiac arrhythmias, and a major cause of morbidity and mortality due to cardioembolic stroke. The left atrial appendage is the major site of thrombus formation in non-valvular atrial fibrillation. Loss of atrial systole in atrial fibrillation and increased relative risk of associated stroke point strongly toward a role for stasis of blood in left atrial thrombosis, although thrombus formation is multifactorial, and much more than blood flow irregularities are implicated. Oral anticoagulation with vitamin-K-antagonists is currently the most effective prophylaxis for stroke in atrial fibrillation. Unfortunately, this treatment is often contraindicated, particularly in the elderly, in whom risk of stroke is high. Moreover, given the risk of major bleeding, there is reason to be skeptical of the net benefit when warfarin is used in those patients. This work reviews the pathophysiology of cardioembolic stroke and critically spotlights the current status of preventive anticoagulation therapy. Various techniques to exclude the left atrial appendage from circulation were discussed as a considerable alternative for stroke prophylaxis.

Assessment of left atrial volume and function by real-time three-dimensional echocardiography

BACKGROUND

Determination of left atrial (LA) size and function is important in clinical decision-making. Calculation of LA volume (LAV) is the most accurate index of LA size.

AIM

To compare real-time 3-dimensional echocardiography (RT3DE) and 2-dimensional echocardiography (2DE) for calculation of LAV and function.

METHODS

Fifty patients were studied using 2DE and RT3DE for calculating LAV including: Maximum (V max), minimum (V min) and pre-atrial contraction (V pre A) volumes. For 2DE, the formula: LAV=8(A1) (A2)/3pi (L) was used, while for RT3DE, offline analysis was performed using commercially available software. LA function indices including Total Atrial Stroke Volume (TASV), active ASV (AASV), Total Atrial Emptying Fraction (TAEF), active AEF (AAEF), passive AEF (PAEF), and Atrial Expansion Index (AEI) were calculated.

RESULTS

Patients were classified into 2 equal groups: group I with normal V max (< 50 ml) and group II with V max (> or = 50 ml). Good correlation was obtained between RT3DE and 2DE for LAV (r=0.64, p=0.001) in group I and (r=0.83, p<0.0001) in group II. In group I, LAV and functions showed no significant difference by both techniques, while in group II, the V min and V pre A were significantly lower by RT3DE than 2DE (p=0.009, 0.006). TAEF, AEI, and PAEF indices were significantly higher by RT3DE than 2DE in group II.

CONCLUSION

RT3DE provides a reproducible assessment of active and passive LA function by volumetric cyclic changes. It is comparable and may be superior to 2DE due to its higher sensitivity to volume changes.

Role of Biplane Echocardiography in a Large-volume Clinical Practice: Revamping Strategies for Echocardiography in a Limited Time

OBJECTIVES

We determined the feasibility, learning curve, time efficacy, and the quality of imaging during biplane echocardiography performed in clinical practice with a view to reduce a sonographer's time for image acquisition.

BACKGROUND

Multidimensional echocardiographic imaging has improved the assessment of cardiac geometry and function in clinical settings. However, concerns regarding ease of performance and effects on overall clinical work flow remain inadequately addressed.

METHODS

The study included 100 consecutive unselected patients referred to our echocardiography laboratory. They were randomized to conventional or biplane echocardiography performed by a sonographer without previous knowledge of biplane imaging. Image acquisition time and variables influencing the learning curve and overall image quality were analyzed.

RESULTS

Mean time required for biplane and mono-plane imaging was not different in the first 24 cases. In the remaining cases, mean image acquisition time was reduced significantly in 58 cases (76.3%): biplane, 5.6 minutes (SD 1.3); and monoplane, 6.6 minutes (SD 1.6) ( P = .0003). For both techniques, scanning time was not affected by referral pattern, body habitus, or underlying cardiac lesion. Overall, biplane scanning resulted in reduction in echocardiographic imaging time of 9.1%, maintaining an acceptable image quality in 87% of patients. In the last 20 cases, new software design and superior instrumentation technique improved the mean time gain to 15%.

CONCLUSION

In a high-volume echocardiography laboratory, biplane imaging effectively reduces sonographer time for imaging and improves throughput by increasing the number of comprehensive ultrasound studies that can be performed in a limited time.