Comparative assessment of left atrial appendage by transesophageal and combined two- and three-dimensional transthoracic echocardiography

Objective: Our objective was to compare the utility of combined two‐dimensional (2D) transthoracic echocardiography (TTE) and three‐dimensional (3D) TTE versus 2D transesophageal echocardiography (TEE) in evaluation of the left atrium (LA) and LA appendage (LAA) for clot. Background: 2DTEE, usually performed to visualize the LAA, is semi‐invasive and not without risks. With improved technology the LAA has been increasingly visualized by 2DTTE and 3DTTE in many patients. Methods: We compared combined 2DTTE and 3DTTE with 2DTEE in evaluating the LA/LAA for a thrombus. Ninety‐two patients underwent 2DTTE, 3DTTE, and 2DTEE. An additional 20 patients, in whom TEE could not be performed, underwent 2DTTE and 3DTTE. Results: LA and LAA could be visualized in all patients. Of 92 patients studied, 74 had no thrombus and 7 had thrombus in the LAA by all modalities. Eleven patients, 9 with atrial fibrillation (AF), had a suspected thrombus by 2DTEE, but 3DTTE cropping clearly showed these to be prominent pectinate muscles which were seen in short axis on 2DTEE as rounded echo dense masses and therefore mimicked thrombi. These 9 patients with AF underwent successful cardioversion without any complications. Of the 20 patients in whom TEE could not be performed, 19 had no thrombus in the LA/LAA and 1 had a clot in the LAA. These 19 patients underwent successful cardioversion without complications. Conclusions: Our preliminary study suggests that combined 2DTTE and 3DTTE has comparable accuracy to TEE in evaluating the LA and LAA for thrombus. In some patients TEE, but not 3DTTE, may misdiagnose pectinate musculature as thrombus.     

Left atrial volume assessed by transthoracic three dimensional echocardiography and magnetic resonance imaging: dynamic changes during the heart cycle in children

OBJECTIVE—To assess the dynamic changes in left atrial volume by transthoracic three dimensional echocardiography and compare the results with those obtained by magnetic resonance imaging (MRI).
DESIGN AND PATIENTS—30 healthy children (15 boys and 15 girls, aged 8 to 13 years) underwent examination by three dimensional echocardiography and MRI.
METHODS—Three dimensional echocardiography of the left atrium was performed using rotational acquisition of planes at 18° intervals from the parasternal window with ECG gating and without respiratory gating. Volume estimation by MRI was performed with a slice thickness of 4-8 mm and ECG triggering during breath holding in deep inspiration. A left atrial time-volume curve was reconstructed in each child.
RESULTS—Left atrial maximum and minimum volumes averaged 24.0 ml/m² and 7.6 ml/m² by three dimensional echocardiography, and 22.1 ml/m² and 11.9 ml/m² by MRI. The greater left atrial minimum volume in the latter was at least in part a result of breath holding. Dynamic changes in left atrial volume during the heart cycle were detectable by both methods. The higher temporal resolution of three dimensional echocardiography allowed a more precise evaluation of different phases.
CONCLUSIONS—Three dimensional echocardiography and MRI were both useful methods for studying the physiological volume changes in the left atrium in children. These methods may be used for further study of the systolic and diastolic function of the heart.


Keywords: three dimensional echocardiography; magnetic resonance imaging; left atrial volume; children     

Two-dimensional color Doppler echocardiography for left ventricular stroke volume assessment: a comparison study with three-dimensional echocardiography

Aim: Whether measurement of left ventricular outflow tract diameter (LVOTd) using color Doppler (CD) in order to more accurately define LVOTd is more accurate for determination of stroke volume (SV) than gray scale and compare it with direct measurement of LVOT area (a) using three‐dimensional echocardiography (3DE) for SV determination. Methods and Results: Twenty‐one volunteers were examined. LVOTa was calculated by two‐dimensional echocardiography (2DE) using the following formula: π× (d/2)², d = LVOT diameter by gray scale and CD, respectively. Planimetry of LVOTa was performed in parasternal long axis using 3DE. Eccentricity Index was calculated using the lateral and anterior‐posterior LVOTd. SV was obtained by four different methods: (1) 2D gray scale, (2) 2D color, (3) LVOTa × LVOT velocity time integral, and (4) SV by Simpson's biplane method. Gray scale LVOTd was significantly smaller compared to LVOTd obtained with CD (P < 0.05). Significant differences occurred between LVOTa gray scale and CD (3.29 ± 0.74 cm² vs 3.67 ± 0.70 cm², P < 0.05) and between LVOTa calculated by gray scale in comparison to 3DE planimetry; (3.29 ± 0.74 cm² vs 3.61 ± 0.89 cm², P = 0.011). Half of the subjects had at least 17% difference between the lateral and anterior‐posterior LVOTd. There were significant differences between SV by 2D gray scale and 2D CD (82.8 ± 17.1 mL vs 92.4 ± 16.8 mL, P < 0.05) and between 2D gray scale and 3DE planimetry (82.8 ± 17.1 mL vs 90.7 ± 19.8 mL, P = 0.025). Conclusion: Our study demonstrates LVOT being frequently elliptical. SV and LVOTa were found to be similar when comparing 2DE CD and 3DE planimetry and showed higher values in comparison to 2DE gray scale, which suggests 2DE CD to be an alternative approach for SV assessment.     

Delineation of the etiology of a mass-like echo density in the left ventricle using three-dimensional transthoracic echocardiography

Live/real time three-dimensional transthoracic echocardiography (3DTTE) provides an incremental value in the delineation of various cardiac pathologies. In this study, two-dimensional transthoracic echocardiography (2DTTE) of a 56-year-old patient showing a prominent echo density suggestive of a mass in the left ventricle probably attached to the ventricular side of the anterior mitral leaflet, is reported. Systematic cropping of the 3DTTE dataset showed the mass to be a calcified mitral strut chord viewed in cross section. This is well visualized in the accompanying movie clip. This case highlights the advantage of 3DTTE in which the whole of the ventricle including the mitral valve apparatus is captured in the dataset facilitating cropping at any desired angulation.     

Left atrial volume determination by echocardiography

To validate echocardiographic left atrial volume measurements, 25 patients with mitral stenosis were studied before and after mitral balloon valvuloplasty. Seven normals served as controls. The modified Simpson's rule was used for echocardiographic and angiographic left atrial volume determination from two orthogonal planes. Left atrial antero-posterior diameter was measured from parasternal long axis view and supero-inferior and medio-lateral diameters from apical four-chamber view. Transthoracic echocardiographic left atrial volume correlated well, but systematically underestimated angiographic left atrial volume (y=0.4x+27, r=0.92). Monoplane transesophageal echocardiography did not improve correlation, nor the underestimation. Out of the several left atrial diameters, antero-posterior dimension showed the closest correlation with angiographic volume (r=0.91), which persisted after exclusion of patients with atria >400 ml (r=0.84). Futhermore, relative changes of antero-posterior diameter after mitral valvuloplasty were closely related to the relative changes observed in left atrial volume (r=0.82). Our results suggest that, in spite of a consistent underestimation, bidimensional, transthoracic echocardiographic and angiographic left atrial assessment correlate closely. Moreover, it is suggested that the mere antero-posterior diameter from transthoracic two-dimensional image is sufficient in clinical practice for routine follow-op of left atrial volume.     

Left atrial Frank-Starling law assessed by real-time, three-dimensional echocardiographic left atrial volume changes

Background

The Frank–Starling law describes the relation between left ventricular volume and function. However, only a few studies have described the relation between left atrial volume (LAV) and function.

Objective

To describe an LA Frank–Starling law by studying changes in LAV measured by real‐time, three‐dimensional echocardiography (RT3DE).

Methods

LAV was calculated by RT3DE in 70 patients at end‐systole (LAV_max), end‐diastole (LAV_min) and pre‐atrial contraction (LAV_pre‐A). According to LAV_max, patients were classified into three groups: LAV_max <50 ml (group I), LAV_max 50–70 ml (group II) and LAV_max >70 ml (group III). Calculated indices of LA pump function were active atrial stroke volume (SV), defined as LAV_pre‐A – LAV_min, and active atrial emptying fraction (EF), defined as active atrial SV/LAV_pre‐A ×100%

Results

Active atrial SV was significantly higher in group II than in group I (mean (SD) 19.0 (9.2) vs 8.2 (4.9) ml, p<0.0001), in group III it was non‐significantly lower than in group II (16.7 (12.5) vs 19.0 (9.2) ml). Active atrial SV correlated well with LAV_pre‐A (r = 0.56, p<0.001), but decreased with larger LAV_pre‐A. Active atrial EF tended to be higher in group II than in group I (43.1 (18.2) vs 33.2 (17.5), p<0.10), in group III it was significantly lower than in group II (26.2 (18.5) vs 43.1 (18.2), p<0.01).

Conclusion

A Frank–Starling mechanism in the left atrium could be described by RT3DE, shown by an increase in LA contractility in response to an increase in LA preload up to a point, beyond which LA contractility decreased.     

Incremental benefit of three‐dimensional transthoracic echocardiography in the assessment of left atrial appendage aneurysm leading to severe extrinsic compression of a coronary artery

Left atrial appendage aneurysm (LAA AN) is a rare disease entity, which can be congenital or acquired in nature. We report an adult patient with LAA AN presenting with anginal chest pain in whom live/real time three‐dimensional transthoracic echocardiography (3DTTE) provided incremental value over the two‐dimensional (2D) technique in providing a more comprehensive assessment of the lesion. A literature review of the salient features of LAA AN is also provided in a tabular form.     

Comparison between transesophageal echocardiography and transthoracic echocardiography with harmonic tissue imaging for left atrial appendage assessment

BACKGROUND: Transesophageal echocardiography (TEE) is the method of choice for evaluating both anatomy and function of left atrial appendage (LAA). In contrast, conventional transthoracic echocardiography (TTE) does not result in images of sufficient quality to explore LAA. HYPOTHESIS: The aim of this study was to evaluate the potential role of TTE with harmonic frequency imaging (HFI) for assessing LAA normal anatomy and function. METHODS: The study group comprised 25 patients, (9 men, 16 women, mean age 51 years, range 20-82). The TTE as sessment of LAA both in fundamental frequency imaging (FFI) and HFI was performed using the apical two-chamber view, the longitudinal two-chamber view was used for TEE assessment of LAA. According to image quality, images were categorized into three classes: A: good quality, B: sufficient quality, C: poor quality. RESULTS: Transthoracic echocardiography conventional imaging allowed sufficient LAA visualization (class B) in only 5 of 25 patients (20%); the HFI resulted in adequate LAA visualization in 23 of 25 patients (92%). Images were of good quality (class A) in 18 of 23 patients and of sufficient quality (class B) in 5 of 23 patients. Transesophageal echocardiography achieved good quality images in 24 of 25 patients (96%). Average LAA maximum area determined by HFI and TEE was 3.46 +/-1.17 and 3.59 +/- 1.16 cm2, respectively; LAA minimum area was 1.81 +/- 0.98 and 1.77 +/- 0.97 cm2, respectively. Percent LAA area change was 51 +/- 16.5 and 50.9 +/- 16% with HFI and TEE, respectively. Statistical analysis showed no difference between the data obtained with the two methods. CONCLUSIONS: The results suggest that HFI TNE may be a useful tool for the exploration of LAA.     

Incremental value of live/real time three-dimensional echocardiography in the diagnosis and evaluation of pericardial cyst

Pericardial cysts are rare anomalies of the pericardium that are usually asymptomatic and followed by two-dimensional (2D) echocardiography. Here we report a large pericardial cyst that could not be measured accurately by 2D echocardiography but three-dimensional (3D) echocardiography enabled measurements of the cyst that correlated well with computed tomography measurements. In addition, 3D echocardiography demonstrated the mono-trabeculated nature of the cyst further suggesting the incremental value of 3D echocardiography in the evaluation of pericardial cysts. The cyst was subsequently resected surgically.