Assessment of left atrial appendage by live three-dimensional echocardiography: early experience and comparison with transesophageal echocardiography

BACKGROUND: Live Three-Dimensional Echocardiography (L3D, Sonos 7500, Philips) has the potential to visualize all cardiac structures including left atrial appendage (LAA). We tested the feasibility of evaluating LAA by L3D and compared the findings to transthoracic echocardiography (2D) and in a subset of patients with transesophageal echocardiography (TEE). METHODS: L3D images were obtained in 204 consecutive patients referred for routine 2D or TEE. We performed wide-angled acquisitions from parasternal and apical views. TomTec system (4D Cardio-view, RT 1.2) was used to visualize LAA from multiple vantage points. RESULTS: LAA was adequately visualized by L3D in 139 of 204 (68.1%) patients. L3D visualization was dependent on image quality, suboptimal in 100 and diagnostic in 104 patients. Overall, LAA was visualized in 93 (45.5%) patients by 2D compared to 139 (68.1%) by L3D (P < 0.0001). In 100 patients with suboptimal image quality by L3D, LAA visualization was 16% by 2D and 35% by L3D, whereas in 104 patients with diagnostic images, LAA was visualized in 77 (74%) by 2D and in all 104 (100%) patients by L3D (P < 0.0001). In 37 patients referred for transesophageal echocardiography (TEE), live three-dimensional echocardiography (L3D) visualized left atrial appendage (LAA) in 34 patients with diagnostic image quality. Eight patients with LAA thrombi on TEE had thrombi detected by L3D as well. All patients with LAA thrombus had enlarged LA by both 2D and TEE. CONCLUSIONS: L3D is a promising technique in evaluation of LAA with and without thrombi. In patients with good quality transthoracic images L3D may be used as a screening tool in assessment of LAA.     

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.     

A comparison of intracardiac and transesophageal echocardiography to detect left atrial appendage thrombus in a swine model

Purpose

Transesophageal echocardiography (TEE) is the gold standard in the evaluation for left atrial appendage (LAA) thrombus in patients with atrial fibrillation (AF) and is often performed prior to AF ablation. We routinely use intracardiac echocardiography (ICE) to assist in AF ablation; however, standard right atrial views do not provide adequate visualization of the LAA. As the incidence of thrombus in this population is relatively low, TEE incurs additional risk, cost, and patient discomfort. Novel views of the LAA with ICE may obviate the need for TEE in this population. We tested the hypothesis that due to their proximity, imaging the LAA from the pulmonary artery (PA) would provide equivalent sensitivity and specificity to TEE in detecting LAA thrombus in a swine model.

Methods

Five domestic swine were utilized. Baseline images of the LAA with TEE were obtained. An 8Fr ICE catheter was placed in the left main PA, and imaging of the LAA was repeated. After transseptal puncture, an admixture of 2 cm³ blood and 1,000 IU of thrombin was injected into the LAA, and imaging of the LAA was repeated. Two blinded, independent reviewers experienced in ICE assessed the images and adjudicated both the presence of thrombus and the subjective image quality.

Results

The presence or absence of thrombus was correctly identified in all cases by both reviewers. Both reviewers rated the subjective quality of ICE images superior to TEE.

Conclusions

ICE is equivalent to TEE in imaging LAA thrombus in a porcine model. Whether ICE can provide similar diagnostic accuracy and safety for detecting LAA thrombus in humans remains unproven.     

Transthoracic Versus Transesophageal Two-Dimensional Echo Doppler Determination of Flow Velocity in the Left Atrial Appendage

The assessment of flow velocity (FV) in the left atrial appendage (LAA) by transesophageal echocardiography (TEE) has been reported to be a useful tool as a high risk marker for systemic emboli. The analysis of FV in LAA by transthoracic echocardiography (TTE) has not yet been validated. The purpose of this study was to compare FV measurements in the LAA by TEE and TTE in 30 consecutive patients (age 19–87 years, mean = 55) sent for echocardiographic study with the following diagnosis: stroke (11 patients), mitral stenosis (6 patients), congenital heart disease (4 patients), mitral prosthetic function assessment (2 patients), and other pathologies (7 patients). FV was measured at the outlet and mid-portion of the LAA with TTE, from the apical two-chamber view and with biplane TEE, from the longitudinal two-chamber view. Satisfactory measurements were obtained with TTE from the outlet of the LAA in 96.7% and from the mid-portion of the LAA in 90% of patients. One third of patients were in atrial fibrillation (AF) during the study. The mean FV in the outlet of the LAA was 32.7 ± 2.5 (SE) cm/sec with TTE and was 33.7 ± 3.04 (SE) cm/sec with TEE (r = 0.95). The mean FV in the mid-portion of the LAA was 40.9 ± 3.3 and 42.7 ± 3.9 with TTE and TEE respectively (P = NS) (r = 0.95). There was no difference in the LAA FV determination by TTE and TEE in the subgroup with AF. TTE was able to detect FV < 30 cm/sec with a sensitivity of 88% and specificity of 81% and a positive predictive value of 84% compared with TEE.     

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.     

Low incidence of left atrial or left atrial appendage thrombus in patients with paroxysmal atrial fibrillation and normal EF who present for pulmonary vein antrum isolation procedure

Introduction: The incidence of left atrial appendage (LAA) thrombus in patients with paroxysmal atrial fibrillation (PAF) who present for pulmonary vein antrum isolation procedure (PVAI) is unknown.
Methods and Results: All consecutive patients from January 2000 to June 2004 who underwent a PVAI received a computed tomography (CT) to evaluate LAA thrombus before the procedure and 3 months post-PVAI. All patients were followed prospectively. One thousand two hundred twenty-one patients received a PVAI during the study dates. All patients received a CT pre-PVAI at 3 months, and 601 (49%) received a transesophageal echocardiography (TEE) pre-PVAI. Per protocol, all patients who had CT scans that were positive for LAA thrombus received a TEE. There were 9 patients who had LAA thrombus on CT scan, but only 3 had LAA thrombus on TEE. Using TEE as the gold standard, only 3 patients had an LAA thrombus before PVAI; of these patients, 2 had chronic AF with average ejection fraction (EF) of 48% and 1 patient had PAF with EF 25%. No patients with PAF and normal EF had LAA thrombus. Patients with LAA thrombus pre-PVAI had lower EF than patients without LAA thrombus (40% vs. 53%, P = 0.007) but had similar LA size (5.0 vs. 4.5 cm, P = 0.77). No other differences in baseline characteristics were noted.
Conclusions: In this registry of 1,221 patients, we did not observe LA thrombus in PAF patients with normal EF who present for PVAI. Prescreening CT alone is likely to be sufficient in paroxysmal AF patients with normal EF, and the use of TEE may not be needed.     

Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

BACKGROUND: Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined. METHODS AND RESULTS: We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P <.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit. CONCLUSIONS: LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.     

Transthoracic echocardiographic predictors of left atrial appendage thrombus

Transesophageal echocardiography (TEE) is commonly performed to detect the presence of a left atrial appendage (LAA) thrombus in the setting of an embolic event or before an anticipated electrical cardioversion for atrial fibrillation. The predictive value of transthoracic echocardiographic (TTE) findings in these patients has not been well defined. This study evaluated whether TTE findings can predict LAA thrombi using TEE as the gold standard for the identification of LAA thrombi. From November 1995 to March 2003, 10,753 patients underwent TEE to exclude LAA thrombi after embolic events or before cardioversion. Of these, 3,768 patients had complete TTE examinations performed <2 weeks before undergoing TEE. Demographics, TTE, and cardiac rhythm variables were analyzed using univariate and multivariate logistic regression to identify predictors of LAA thrombi diagnosed on subsequent TEE. LAA thrombi were identified by TEE in 199 patients (5.3%). Several TTE variables predicted LAA thrombi by TEE, including mitral stenosis, atrial fibrillation, tricuspid regurgitation, valvular prosthesis, left ventricular dysfunction, and right ventricular dysfunction. Mitral regurgitation was associated with a reduced risk for LAA thrombi (odds ratio 0.61, p = 0.003). A structurally normal heart in sinus rhythm (n = 247, 6.9%) had a 100% negative predictive value for LAA thrombi. In conclusion, several TTE variables were found to be predictive of LAA thrombi. The likelihood of LAA thrombi being found on TEE was infinitely small in the absence of these variables and the presence of sinus rhythm.     

Transthoracic Tissue Doppler Assessment of Left Atrial Appendage Contraction and Relaxation: Their Changes with Aging

Aim: We assessed left atrial appendage (LAA) function using transthoracic tissue Doppler echocardiography (TDE), and examined the influence of aging on LAA contraction and relaxation. Methods: The subjects were 45 consecutive patients with heart disease and 110 healthy individuals. LAA wall motion velocity (LAAWV) at the tip of the LAA was measured using transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE). Results: We successfully recorded and measured LAAWV using TTE in 105 (95%) of the 110 healthy subjects. When angle correction was applied for the Doppler beam in TTE, LAAWV during contraction (LAAWVc) measured by TTE closely correlated with that measured by TEE (r = 0.97), and LAAWV during relaxation (LAAWVr) measured by TTE closely correlated with that measured by TEE (r = 0.95). LAAWVc and LAAWVr measured by TTE correlated significantly with the LAA flow velocities during LAA contraction and LAA relaxation measured by TEE (r = 0.64, P < 0.001; r = 0.53, P = 0.001). In healthy subjects, although LAAWVc remained unchanged with aging, LAAWVr significantly declined with aging (r =?0.48, P < 0.001) and had a significant negative correlation with left atrial dimension and a significant positive correlation with transmitral flow and annulus velocity during early diastole. Conclusion: Transthoracic TDE can provide information on LAA function. LAA relaxation may be impaired with aging and may be accompanied by early diastolic left ventricular dysfunction and chronic overload to the left atrium. (Echocardiography 2010;27:839‐846)     

Use of intracardiac echocardiography to guide implantation of a left atrial appendage occlusion device (PLAATO).

BACKGROUND: Over 90% of thrombi in atrial fibrillation (AF) originate from the left atrial appendage (LAA). Patients with contraindications to anticoagulation are potential candidates for LAA occlusion using the Percutaneous Left Atrial Appendage Transcatheter Occlusion system (PLAATO, ev3 Inc., Plymouth, MN). Transesophageal echocardiography (TEE) is typically used to guide implantation. OBJECTIVE: This study sought to examine the utility of intracardiac echocardiography (ICE) in providing adequate imaging guidance as an alternative to TEE during PLAATO implantation. METHODS: The study group consisted of 10 patients who underwent PLAATO implantation with simultaneous TEE and ICE imaging guidance. ICE was used to perform the following tasks typically fulfilled by TEE: (1) verification of the absence of LAA thrombus, (2) identification of the LAA ostial dimension for device sizing, (3) guidance of transseptal puncture, (4) verification of the delivery sheath position, and (5) confirmation of location and stability of device before its irrecoverable release. The ability of ICE to perform these tasks was assessed from three separate positions: the standard right atrial (RA) position, within the coronary sinus (CS), and the right ventricular outflow tract. RESULTS: ICE imaging of the LAA was optimal from within the CS, although imaging from the proximal pulmonary artery provided better visualization of the distal LAA in cross-section. The LAA dimensions, confirmation of the absence of LAA thrombus, proper positioning of the delivery sheath, verification of location and stability of the device obtained by ICE were consistent with findings from TEE. CONCLUSION: Using nonconventional imaging planes, ICE imaging was able to perform the intraprocedural functions provided by TEE during implantation of the PLAATO left atrial appendage occlusion device.     

64层螺旋CT检测老年心房颤动患者左心耳血栓的价值

目的探讨导管射频消融术前,应用64层螺旋CT检测老年心房颤动患者左心耳血栓的临床价值。方法对102例拟行导管射频消融术的老年心房颤动患者进行心脏64层螺旋CT扫描,并于1周内,经食管超声心动图(TEE)检查。以TEE为参照标准,评价64层螺旋CT诊断患者左心耳血栓的敏感性、特异性、阳性预测值、阴性预测值及准确度,应用κ检验2种方法的一致性。结果 102例患者中,64层螺旋CT检查显示左心耳血栓形成者16例,其中11例经TEE证实,另5例为自发超声显影;64层螺旋CT检查未见血栓征象者86例,其中84例经TEE证实,另2例TEE显示为血栓。64层螺旋CT诊断左心耳血栓的敏感性84.6%,特异性94.4%,阳性预测值68.8%,阴性预测值97.7%,准确度93.1%,2种方法检测左心耳血栓具有较高的一致性(κ=0.724)。结论 64层螺旋CT检测老年心房颤动患者左心耳血栓具有较高的应用价值,未来有可能成为临床上检测左心耳血栓的一种无创、可靠的替代方法。     

Is It Time to Move on from Two-Dimensional Transesophageal to Three-Dimensional Transthoracic Echocardiography for Assessment of Left Atrial Appendage? Review of Existing Literature

Left atrial appendage (LAA) has unique anatomical and physiological properties, which make it a common site for thrombus formation in many cardiovascular and systemic diseases. Assessment of LAA for thrombus thus becomes important in many clinical situations and two-dimensional transesophageal echocardiography (2D TEE), which allows excellent quality images of LAA because of its close proximity to esophagus is routinely used for this purpose. However, it is a semiinvasive procedure, requires more time and involves some degree of patient discomfort. With some training and experience, two-dimensional transthoracic echocardiography (2D TTE) can visualize LAA in most patients with good acoustic windows. A disadvantage of both 2D TTE and 2D TEE is that they provide only a thin slice or section of cardiac structures at any given time limiting their utility in comprehensively assessing the LAA for thrombus. On the other hand, live/real time three-dimensional (3D) TTE overcomes this limitation of both 2D TTE and 2D TEE because of its ability to encompass whole of the LAA in three-dimensions in the acquired data set, which can then be cropped and sectioned systematically at any desired angulation to more definitively look for clot. 3D TTE is also useful in differentiating a clot from pectinate muscles in the LAA, which can mimic a thrombus resulting in patient mismanagement. In addition, 3D TTE is helpful in sectioning a clot for lysis, which has implications in clot resolution. We reviewed the existing literature comparing the relative advantages and disadvantages of 3D TTE versus 2D TEE and found that in patients with good acoustic windows 3D TTE had similar efficacy for detecting LAA thrombus. (Echocardiography 2012;29:112-116)     

Implantation of left atrial appendage occlusion devices and complex appendage anatomy: the importance of transesophageal echocardiography

Percutaneous delivery of left atrial appendage (LAA) occluding devices represents a novel approach for stroke prevention in patients with atrial fibrillation. Transesophageal echocardiography (TEE) has a pivotal role throughout these procedures, facilitating device size selection and ensuring optimal deployment of the device. We report a case of an LAA occluding device implantation in which apparent proper positioning on fluoroscopy was determined by TEE to be malpositioning with a nonocclusive, perpendicular orientation to the plane of the LAA ostium. This problem appeared to be related to a complex, multilobed LAA anatomy and was readily resolved by repositioning of the device under TEE guidance.     

Left atrial appendage septae not visualized with transesophageal echocardiography.

Left atrial appendage (LAA) filter implantation was attempted in an 89 year old male. The LAA size was estimated by transesophageal echocardiography (TEE). Complete LAA obliteration was not achieved. LAA angiography suggested that the LAA was multilobed, likely separated by a thin septae not seen with TEE. MRI or CT may be more appropriate imaging modalities to define LAA anatomy.     

Use of Intracardiac Compared With Transesophageal Echocardiography for Left Atrial Appendage Occlusion in the Amulet Observational Study

ObjectivesThe aim of this study was to compare patient and procedural characteristics, clinical events, and left atrial appendage (LAA) occlusion rates among implantation procedures guided either by intracardiac echocardiography (ICE) or by transesophageal echocardiography (TEE) in the Amulet Observational Study.BackgroundTEE is standard for intraprocedural imaging during LAA occlusion. ICE is an alternative enabling local rather than general anesthesia.MethodsThe Amulet Observational Study is a prospective, multicenter, post-market study of the Amulet device in patients with atrial fibrillation at risk for thromboembolism from the LAA. Procedures were guided by ICE in the left atrium or TEE. A clinical events committee adjudicated serious adverse events. LAA closure was assessed by a core laboratory 1 to 3 months post-implantation.ResultsNine hundred fifty-five procedures were TEE guided and 130 (12%) were ICE guided. Local anesthesia was used in 93% of ICE-guided cases. Implantation success was >99% in both groups (p = 1.00). The procedure was longer (40 ± 31 min vs. 33 ± 21 min; p = 0.01) and contrast use higher (145 ± 157 ml vs. 98 ± 76 ml; p < 0.01) for ICE cases. LAA closure rate was 100% using ICE and 98% using TEE. Vascular access serious adverse events occurred in 0.8% of ICE patients and 1.5% of TEE patients (p = 0.52). Pericardial effusions or tamponade was observed at rates of 2.5% per year and 1.7% per year in ICE and TEE patients, respectively (p = 0.57). Rates of ischemic stroke (4.1% per year vs. 2.6% per year; p = 0.37) and major bleeding (8.2% per year vs. 10.6% per year; p = 0.44) did not differ significantly between ICE and TEE patients.ConclusionsAmulet LAA occlusion procedures guided by ICE and TEE resulted in comparable clinical event and LAA closure rates, without differences in procedural or vascular complications despite longer procedures and more contrast use.     

Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

BACKGROUND: In patients with atrial fibrillation (AF) eligible for electrical cardioversion (C), the guided approach with transesophageal echocardiography (TEE) allows to avoid the 3 weeks of recommended precardioversion anticoagulation therapy. However, after sinus rhythm restoration, at least other 4 weeks of oral anticoagulation therapy are indicated, due to the postcardioversion thromboembolic risk related to left atrial (LA) and left atrial appendage (LAA) stunning. The aim of this study was to prospectively assess the effectiveness and the safety of anticoagulation therapy discontinuation 7 days after C using low-molecular-weight heparins (LMWH) in a selected group of patients who underwent a pre-C and 7 days post-C TEE evaluation. METHODS: One hundred one patients (74 patients with nonvalvular AF and 27 patients with atrial flutter lasting >48 h and history of AF) were enrolled into the study. Two patients refused the TEE, therefore, in 99/101, we performed a first TEE and, within 24 h, a C if there were no LAA thrombi, complex aortic plaques or severe spontaneous echocontrast. After C and 7 days of home-administered enoxaparin, a second TEE was carried out. In the absence of any new thrombi, severe spontaneous echocontrast and/or low emptying velocity of LAA, the therapy with enoxaparin was stopped; otherwise, anticoagulation therapy with enoxaparin was overlapped with oral anticoagulation and continued for at least 3 weeks. All patients were clinically followed at 1, 6 and 12 months after C. RESULTS: Sinus rhythm was restored in 68/99 patients after successful C. The second TEE was carried out in 53 patients. At 1 month follow-up, no thromboembolic events were recorded either in patients at risk who had continued the oral anticoagulant therapy for at least 3 weeks or in those who suspended LMWH after 7 days post-C TEE. Between the 2nd and 12th month, three ischemic strokes occurred, all in the group of patients who had anticoagulation therapy for at least 3 weeks and had shown LAA velocity <25 cm/s at first or second TEE. No thromboembolic events were recorded in patients with normal LAA velocity; conversely, among the patients who had shown low LAA velocity at either TEE, three suffered from ischemic stroke. In two of these three patients, low LAA velocity was detected only at post-C TEE. CONCLUSIONS: A brief anticoagulation therapy using LMWH appears to be safe and feasible. The 7 days post-C TEE can well-define patients without LAA stunning at low thromboembolic risk, who may take advantage of an early interruption of enoxaparin as an alternative to long oral anticoagulation. The LAA stunning, even in the absence of other thromboembolic risk factors, could select a group of patients at high risk who should continue oral anticoagulation indefinitely or until signs of LAA dysfunction disappear.     

Congenital Absence of the Left Atrial Appendage Visualized by 3D Echocardiography in Two Adult Patients

Congenital absence of left atrial appendage (LAA) is an extremely rare condition and its physiological consequences are unknown. We present two cases of incidental finding of a congenitally absent LAA in a 79‐year‐old male who presented for routine transesophageal echocardiogram (TEE) to rule out intracardiac thrombus prior to placement of biventricular implantable cardioverter‐defibrillator and a 54‐year old female who presented for TEE prior to radiofrequency ablation of atrial fibrillation. Characterization of patients with such an absence is important because congenitally absent LAA may be confused with flush thrombotic occlusion of the appendage. There are very few published reports of congenital absence of LAA. To our knowledge, our report is the first to demonstrate the congenital absence of LAA by 3D transesophageal echocardiography.     

Analysis of the left atrial appendage morphology by intracardiac echocardiography in patients with atrial fibrillation

Background  

Detailed information regarding the structure and dimensions of the left atrial appendage (LAA) is required to guide implantation of LAA occlusion devices in patients with atrial fibrillation (AF). Currently, this procedure is guided by transesophageal echocardiography (TEE).     

Role of transesophageal echocardiography in the prediction of thromboembolism in patients with chronic nonvalvular atrial fibrillation

The purpose of this study was to determine whether parameters derived from transesophageal echocardiography (TEE) could predict thromboembolism in patients with chronic nonvalvular atrial fibrillation (AF). Eighty-nine patients, mean age 66+/-9 years, who underwent TEE in 1996 to 1999 were studied. The clinical endpoint was a thromboembolic event, including transient ischemic attack (TIA). Sixty-seven patients (75%) were anticoagulated with warfarin after TEE. After a follow-up period of 29+/-10 months, 1 patient died suddenly, 4 had a thromboembolism, and 3 had a TIA; the annual embolic event rate was 3.3%. Left atrial appendage (LAA) thrombus (86% vs 17%, p<0.001), LAA dysfunction (LAA velocity <20 cm/s; 71% vs 25%, p=0.009), and severe LA spontaneous echo contrast (29% vs 2%, p=0.002) were more prevalent in patients with an embolic event than in those without. In patients with LAA thrombus, the annual event rate was 11% as compared with 1.2% in those without (p=0.004). On the Cox proportional hazards model analysis, LAA thrombus (chi-square 7.0, p=0.008), severe LA spontaneous echo contrast (chi-square 7.0, p=0.008), and LAA dysfunction (chi-square 5.9, p=0.015) were significantly related to thromboembolism. Multivariate analysis revealed that LAA thrombus (chi-square 5.5, p=0.019) and LAA dysfunction (chi-square 4.0, p=0.045) were the independent predictors. In conclusion, TEE parameters, particularly the presence of LAA thrombus, can be used to assess thromboembolic potential in patients with chronic nonvalvular AF.     

Periprocedural Intracardiac Echocardiography for Left Atrial Appendage Closure: A Dual-Center Experience

ObjectivesThis dual-center study sought to demonstrate the utility and safety of intracardiac echocardiography (ICE) in providing adequate imaging guidance as an alternative to transesophageal echocardiography (TEE) during Amplatzer Cardiac Plug device implantation.BackgroundOver 90% of intracardiac thrombi in atrial fibrillation originate from the left atrial appendage (LAA). Patients with contraindications to anticoagulation are potential candidates for LAA percutaneous occlusion. TEE is typically used to guide implantation.MethodsICE-guided percutaneous LAA closure was performed in 121 patients to evaluate the following tasks typically achieved by TEE: assessment of the LAA dimension for device sizing; guidance of transseptal puncture; verification of the delivery sheath position; confirmation of location and stability of the device before and after release and continuous monitoring to detect procedural complications. In 51 consecutive patients, we compared the measurements obtained by ICE and fluoroscopy to choose the size of the device.ResultsThe device was successfully implanted in 117 patients, yielding a technical success rate of 96.7%. Procedural success was achieved in 113 cases (93.4%). Four major adverse events (3 cardiac tamponades and 1 in-hospital transient ischemic attack) occurred. There was significant correlation in the measurements for device sizing assessed by angiography and ICE (r = 0.94, p < 0.0001).ConclusionsICE imaging was able to perform the tasks typically provided by TEE during implantation of the Amplatzer Cardiac Plug device for LAA occlusion. Therefore, we provide evidence that the use of ICE offered accurate measurements of LAA dimension in order to select the correct device sizes.