Recurrent syncope after left atrial appendage occlusion

We present the case of a 72‐year‐old woman with permanent atrial fibrillation and contraindication to long‐term oral anticoagulant therapy who underwent left atrial appendage (LAA) occlusion. A 24‐mm Amplatzer Cardiac Plug (St Jude Medical) device was deployed. The inferior part of the external disc of the device appeared to be over the posterior leaflet of the mitral valve but no significant mitral stenosis or mitral regurgitation was detected before deployment. After the procedure the patient suffered several syncopes when she tried to stand up. A transesophageal echocardiography (TEE) was performed and no significant differences on the device position were detected, it was not possible to perform the TEE in a stand‐up position due to the patient symptoms (hypotension, tachycardia, dizziness, and loss of consciousness). After discussion with the surgical team, surgical removal of the device and surgical exclusion of LAA was performed. The symptoms disappeared and the patient was discharged. In the best of our knowledge, this is the first time that recurrent syncope has been described as a complication of LAA occlusion. © 2014 Wiley Periodicals, Inc.     

Intracardiac echocardiography with ultrasound probe placed in the upper left pulmonary vein to guide left atrial appendage closure: First description

Intracardiac echocardiography (ICE) has become an effective alternative to trans‐esophageal echocardiography (TEE) as a guidance during interventional procedures for structural heart diseases, allowing to proceed under conscious sedation. To guide percutaneous left atrial appendage (LAA) closure, the ICE probe is usually placed in the right atrium, in the pulmonary artery or in the left atrium (LA); however, the views from the right atrium or the pulmonary artery are often suboptimal, debarring a complete visualization of the LAA and the surrounding structures, whereas the LA location requires trans‐septal puncture, may provoke LA wall mechanical stimulation and is often associated with unstable position of the ICE probe. In our case, after a second trans‐septal puncture, the ICE probe was placed in the upper left pulmonary vein; this was safely performed and provided an optimal imaging of the LAA, comparable to that obtained by TEE, thus warranting an adequate guide during all procedural steps.     

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.     

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)     

Comparison of Tissue Doppler Dynamics with Doppler Flow in Evaluating Left Atrial Appendage Function by Transesophageal Echocardiography in Prehypertensive and Hypertensive Patients

Increased blood pressure (BP) is associated with an increase in cardiovascular mortality and morbidity. We aimed to analyze the effect of increased BP onto the function of left atrial appendage (LAA) in early stages of hypertension. Transesophageal echocardiography (TEE) was prospectively performed to assess LAA functions in 120 patients with increased BP, and in 58 normotensive subjects without cardiovascular disease. Patients with increased BP were divided according to Joint National Committee VII (JNC VII) report: prehypertensive,stage‐1 hypertensive and stage‐2 hypertensive patients. During TEE, LAA late‐emptying velocities (LAAEV) were significantly reduced only in stage‐2 hypertensives as compared with control group (P < 0.001). In contrast, LAA late‐contracting velocity (LAA TDI‐D2) was significantly reduced in prehypertensive,stage‐1 hypertensive and stage‐2 hypertensive patients, when compared with control group (P < 0.05, P < 0.001, and P < 0.001, respectively). The LAA maximal areas were increased significantly only in stage‐2 hypertensive patients when compared with control group (P < 0.05). During TEE, left atrial spontaneous echocardiographic contrast was found in 2 of 36 patients in prehypertension group, in 7 of 40 patients in stage‐1 hypertension group, and in 10 of 44 patients in stage‐2 hypertension group. Left atrial thrombi were observed in 3 (6.8%) patients of stage‐2 hypertension group. In conclusion, in patients with untreated prehypertension and hypertension, elevation of afterload imposed on left atrium involved both left atrium and LAA, resulting in impairment of the LAA function. Tissue Doppler imaging (TDI) enables the detection of this functional impairment in early stages of hypertension, even in prehypertensive phase, when compared with conventional Doppler flow measurement of the LAA. Even in prehypertensive phase, BP should be decreased to normal levels to prevent the LAA dysfunction. (Echocardiography 2010;27:677‐686)     

房颤患者左心耳功能评估和血栓识别超声学进展

左心耳（LAA）是房颤患者最常见心源性血栓来源。持续性房颤（AF）患者左心房血栓可能会因为形态变异而导致诊断困难,由多普勒超声衍生而来的新型成像模式,如组织多普勒成像（TDI）和斑点跟踪超声心动图（STE）,以及由组织速度显像(TVI)得出的新技术-应变成像（SI）和应变速率成像（SRI）分析可能会对识别这些血栓有帮助。LAA游离壁较薄,现有的技术很难从视觉上评估它的机械功能,而LAA基底部的肌小梁如左脊（LLR）和基底内侧二尖瓣前庭BMAS,在某种程度上能反应LAA的机械活动,从而通过TEE进行LAA功能评估。本文综述了这方面的进展。     

Prevalence and Clinical Characteristics Associated With Left Atrial Appendage Thrombus in Fully Anticoagulated Patients Undergoing Catheter‐Directed Atrial Fibrillation Ablation

LAA Thrombus Among Anticoagulated AF Patients. Introduction: Catheter‐directed atrial fibrillation (AF) ablation is contraindicated among patients with left atrial appendage (LAA) thrombus. The prevalence of LAA thrombus among fully anticoagulated patients undergoing AF ablation is unknown. Methods and Results: We retrospectively evaluated the prevalence of LAA thrombus among 192 consecutive patients undergoing AF ablation between July 2006 and January 2009. Seven of 192 patients (3.6%) had evidence of thrombus on transesophageal echocardiogram (TEE) despite being fully anticoagulated on warfarin (international normalized ratio [INR] 2–3) for 4 consecutive weeks prior to echocardiogram. Univariate analysis demonstrated that structural heart disease, large left atrial dimension, and number of AF ablations were associated with thrombus. Three patients with thrombus had paroxysmal AF with normal LV function. Conclusion: Despite full anticoagulation, 3.6% of patients undergoing AF ablation had LAA thrombus. We recommend that all patients, regardless of LV function or left atrial size, should undergo preprocedural TEE to exclude the presence of LAA thrombus. (J Cardiovasc Electrophysiol, Vol. 21, pp. 849‐852, August 2010)     

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.     

多平面经食管超声心动图在鉴别左心耳内血栓与梳状肌的作用

目的;了解多平面经食管超声心动图（TEE）在鉴别左心耳内血栓与梳状肌的作用。方法：采用多平面TEE观察54例风湿性心脏病二尖瓣狭窄患者左心耳结构。结果：54例患者中,30例在0～90°扫描切面左心耳尖部或侧壁出现直径0．30～0．78cm大小回声,类似血栓形成,但当扫描切面转至110～135°时,左心耳底部可见2～4个平行排列、清晰的点状或条索状回声,为梳状肌,其中12例为手术证实;24例在0～90°C以及110～135°时左心耳和（或）左心房体部可见直径1．0～3．4cm大小边缘清楚、致密的回声光团,为血栓形成,其中18例为手术证实。结论：多平面TEE能清晰观察左心耳内发达的梳状肌,并能与血栓作出可靠的鉴别诊断。     

Atrial fibrillation ablation in patients with known sludge in the left atrial appendage

Purpose

Transesophageal echocardiography (TEE) is routinely used to assess for thrombus in the left atrium (LA) and left atrial appendage (LAA) in patients undergoing atrial fibrillation (AF) ablation. However, little is known about the outcome of AF ablation in patients with documented LAA sludge. We hypothesize that AF ablation can be performed safely in a proportion of patients with sludge in the LAA and may have a significant benefit for these patients.

Methods

We performed a retrospective analysis of all patients undergoing AF ablation at New York University Langone Medical Center (NYULMC) from January 1st 2011 to June 30, 2013. Patients with sludge found on their TEE immediately prior to AF ablation were identified and followed for stroke, AF recurrence, procedural complications, major bleeding, or death.

Results

Among 1,076 patients who underwent AF ablation, 8 patients (mean age 69?±?13 years; 75 % men) with sludge were identified. Patients with sludge in their LAA had no incidence of early or late occurrence of stroke during mean follow-up of 10 months. One patient had a left groin hematoma, and two patients had atrial tachycardias that needed a repeat ablation. TEE at the time of repeat ablation demonstrated the presence of spontaneous echo contrast (smoke) and resolution of sludge. There were no deaths.

Conclusion

In a cohort of eight patients with LAA sludge who underwent AF ablation, no significant thromboembolic events occurred during or after the procedure. AF ablation can be performed safely and may be beneficial in these patients. Larger studies are warranted to better determine the most appropriate management route.     

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 appendage occlusion using a Watchman device in a transplanted heart with biatrial anastomosis

A percutaneous left atrial appendage (LAA) occlusion using a Watchman device was performed in a patient with prior biatrial anastomosis orthotopic heart transplant (OHT). Due to the anatomical changes following biatrial anastomosis, transesophageal echocardiography (TEE) imaging and transseptal puncture become technically challenging. We describe how the standard LAA views on TEE were obtained for device sizing, and how the transseptal puncture was modified to cross the scarred septum. This case demonstrates that LAA occlusion using a Watchman device in biatrial anastomosis OHT is safe and can successfully be done.     

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.     

Evaluation of Left Atrial Appendage Functions in Patients with Thrombus and Spontaneous Echo Contrast in Left Atrial Appendage by Using Color Doppler Tissue Imaging

Objective: Thrombus and spontaneous echo contrast (SEC) develops in the left atrial appendage (LAA) when LAA function is disturbed. Decrease of left atrial appendage emptying velocity shows LAA dysfunction. The purpose of this study is to examine the incidence of SEC and/or thrombus in LAA in patients with acute myocardial infarction and to assess the LAA function using color Doppler tissue imaging (CDTI) of the patients with detected SEC and/or thrombus. Method and Results: Eighty‐four patients with acute myocardial infarction were included in the study. Spontaneous echo contrast and/or thrombus were observed in 24 (29%) of the 84 patients who were categorized as group 1 (mean age 59 ± 12 years). Sixty patients (71%) without thrombus and/or SEC in LAA were categorized as group 2 (mean age 58 ± 8 years). Left atrial diameters and left ventricular ejection fraction were measured by using transthoracic echocardiography. Left atrial appendage emptying and LAA filling velocity were measured by transesophageal Doppler echocardiography. Systolic appendage tissue velocities (SaV cm/s) were measured at the basal, mid, and tip of medial wall of LAA by transesophageal CDTI. Group 1 had significantly decreased LAA emptying velocities, mid SaVs, and left ventricular ejection fractions compared to group 2 (37 ± 9 cm/s vs 55 ± 22 cm/s, 3.1 ± 1.6 cm/s vs 3.7 ± 1.2 cm/s, and 47 ± 13% vs 58 ± 10%, respectively, P = 0.002, P = 0.04, P = 0.03). Group 1 had significantly increased left atrial diameters compared to group 2 (40 ± 5 mm vs 36 ± 6 mm P = 0.001). Left atrial appendage‐filling velocities, basal SaVs and tip SaVs in group 1 were lower than those in group 2 but not significantly. Conclusions: Mid‐SaV of LAA medial wall and LAA emptying velocity decrease in patients with thrombus and/or SEC were an indication of functional disorder of LAA. Color Doppler tissue imaging appears to be a clinically applicable and reliable imaging technique that allows quantitative assessment of regional LAA systolic function.     

Clinical Significance of the Left Atrial Appendage Orifice Area

Objective The left atrial appendage (LAA) is one of the major sources of cardiac thrombus formation. Three-dimensional transesophageal echocardiography (TEE) made it possible to perform a detailed evaluation of the LAA morphologies. This study aimed to evaluate the clinical implications of the LAA orifice area. Methods A total of 149 patients who underwent TEE without significant valvular disease were studied. The LAA orifice area was measured using three-dimensional TEE. The patients were divided into two groups according to the LAA orifice area (large LAA orifice group, ≥median value, and small LAA orifice group). The clinical characteristics and echocardiographic findings were evaluated. Results The median LAA orifice area among all patients was 4.09 cm² (interquartile range 2.92-5.40). The large LAA orifice group were older (67.2±10.4 vs. 62.4±15.3 years, p=0.02), more often had hypertension (66.7% vs. 44.6%, p=0.007), and atrial fibrillation (70.7% vs. 39.2%, p＜0.001) than the small LAA orifice group. Regarding the TEE findings, the LAA flow velocity was significantly lower (33.7±20.0 vs. 50.2±24.3, p＜0.001) and spontaneous echo contrast was more often observed (21.3% vs. 8.1%, p=0.02) in the large LAA orifice group. Multivariate models demonstrated that atrial fibrillation was an independent predictor of the LAA orifice area. In the analysis of atrial fibrillation duration, the LAA orifice area tended to be larger as patients had a longer duration of atrial fibrillation. Conclusion Our findings indicated that a larger LAA orifice area was associated with the presence of atrial fibrillation and high thromboembolic risk based on TEE findings. A continuation of the atrial fibrillation rhythm might lead to the gradual expansion of the LAA orifice.     

Left atrial appendage closure with Amplatzer cardiac plug for stroke prevention in atrial fibrillation: Initial Asia‐Pacific experience

Background : Left atrial appendage (LAA) is the main source of left atrial thrombus that causes stroke in patients with non‐valvular atrial fibrillation (NVAF). This study reported the initial safety, feasibility, and 1‐yr clinical outcomes following AMPLATZER cardiac plug (ACP) implantation in Asia‐Pacific region.Methods : Twenty NVAF patients (16 males, age 68 ± 9 yr) with high risk for developing cardioembolic stroke (CHADS₂ score: 2.3 ± 1.3) and contraindications to warfarin received ACP implants from June 2009 to May 2010. Patients received general anesthesia (n = 9) or controlled propofol sedation (n = 11) and the procedures were guided by fluoroscopy and transesophageal echocardiography (TEE). Clinical follow‐up was arranged at 1 month and then every 3 months after implantation, whereas, a TEE was scheduled at 1 month upon completion of dual anti‐platelet therapy.Results : The LAA was successfully occluded in 19/20 patients (95%) at two Asian centers. One procedure was abandoned because of catheter‐related thrombus formation. Other complications included coronary artery air embolism (n = 1) and TEE‐attributed esophageal injury (n = 1). The median procedural and fluoroscopic times were 79 (IQR: 59–100) and 18 (IQR 12–27) minutes, respectively. The mean size of implant was 23.6 ± 3.1 mm. The average hospital stay was 1.8 ± 1.1 days. Follow‐up TEE showed all the LAA orifices were sealed without device‐related thrombus formation. No stroke or death occurred at a mean follow‐up of 12.7 ± 3.1 months. Conclusions : Our preliminary data suggested LAA closure with ACP is safe, feasible with encouraging 1‐yr clinical outcomes. Further large‐scaled trials are needed to confirm the efficacy of this device. © 2011 Wiley Periodicals, Inc.     

Percutaneous Epicardial Left Atrial Appendage Closure: Intermediate‐Term Results

Chronic Percutaneous Epicardial Appendage Closure. Objectives: To assess the chronic safety and feasibility of percutaneous epicardial closure of the left atrial appendage (LAA) guided by electrical navigation. Background: Atrial fibrillation (AF) is associated with stroke, and LAA occlusion may be a useful nonpharmacologic strategy for stroke prevention in AF. Methods: Percutaneous epicardial access was obtained in 6 dogs under general anesthesia. The ligation system included a grabber that captures the LAA guided by local electrograms (EGMs) and a looped hollow suture preloaded with a central wire enabling control and visualization. After a satisfactory position is confirmed the loop is tightened remotely, and the suture cut. Transesophageal echocardiography (TEE) assessed LAA dimensions and flow. LAA EGMs were recorded pre‐ and postclosure, and neurohormonal markers measured. Pathologic examination was performed. Results: LAA ligation was successful in all dogs. LAA flow was immediately abolished in 5 of 6 dogs. Disappearance of local LAA EGMs following ligation was observed in all animals. Follow‐up TEE at mean 54 days (range 23‐75 days) documented residual flow in only the first 2 dogs. Prior to necropsy the LAA was examined at thoracotomy in 3 animals. Following a minor design change, complete closure and fibrosis with a remnant atretic LAA was noted in all animals. No damage to adjacent structures was noted. Neurohormonal markers were unchanged. Conclusion: Percutaneous epicardial LAA ligation guided by electrical navigation is feasible with promising intermediate‐term results in the canine model. The technique may be useful as an alternative to existing methods of LAA obliteration in humans. (J Cardiovasc Electrophysiol, Vol. 22, pp. 64‐70, January 2011)     

Percutaneous management of left atrial appendage perforation during device closure

A 76‐year‐old male patient was admitted for percutaneous left atrial appendage (LAA) closure because of chronic atrial fibrillation and a history of gastrointestinal bleeding under oral anticoagulation. The procedure was complicated by perforation of the LAA with the lobe of the closure device being placed in the pericardial space. Keeping access to the pericardial space with the delivery sheath, the LAA closure device was replaced by an atrial septal defect closure device to seal the perforation. Then the initial LAA closure device was reimplanted in a correct position. Needle pericardiocentesis was required but the subsequent course was uneventful. © 2013 Wiley Periodicals, Inc.     

Left atrial appendage activity translation in the standard 12-lead ECG

LAA Activity in Surface ECG. Introduction: Interatrial frequency gradient is used to guide catheter ablation of atrial fibrillation (AF). Lead V1 adequately reflects right atrial activity, but reliable tools for noninvasive estimation of right versus left fibrillatory frequency are lacking. In this study, patients with dissociated left and right atrial rhythms were studied in order to identify which surface electrocardiographic (ECG) leads that most closely reflect the left atrial activity. Methods: Two consecutive patients with atrial tachycardia confined to the left atrial appendage (LAA) detected during catheter ablation of AF were included (2 men, 54 and 72 years old). A 12‐lead ECG was recorded simultaneously with electrograms from the right and left atrial appendages (RAA/LAA). AF frequency spectra were calculated from all 12 leads using spatiotemporal QRST cancellation and Welch periodogram. The dominating atrial cycle length (DACL) in the surface ECG leads was subsequently compared with the invasively measured LAA cycle length. Results: LAA activation frequency was seen as a prominent peak in the frequency–power spectrum derived from frontal plane leads as well as lead V1. The absolute difference in noninvasively and invasively measured LAA cycle length was lowest for leads aVR, II, aVF, III, and V1 in which it was in the range of 2–4 ms. Conclusion: Prominent left atrial component is present in the majority of standard ECG leads, including those traditionally associated with right atrial activity such as V1. Spectral analysis is able to extract the LAA component on surface ECG. (J Cardiovasc Electrophysiol, Vol. 22, pp. 706‐710, June 2011)     

Sudden floating thrombus formation on the delivery cable before Amplatzer‐Amulet device deployment during left atrial appendage occlusion: The need for a standardized anticoagulation

Anticoagulation is of paramount importance during left atrial appendage occlusion procedure (LAAOP) to prevent periprocedural stroke. We present the case of a 66‐year‐old male patient who was scheduled to undergo LAAOP because of a prior intracranial bleeding. After transesophageal echocardiography‐guided transseptal puncture, intravenous heparin 5,000 IUs were administered obtaining an ACT greater than 300 s. We planned to implant an Amplatzer‐Amulet 25 mm LAA occluder through the dedicated 12F delivery sheath. After starting the tug test, TEE suddenly showed a floating thrombus whose proximal part was connected to the delivery cable. Because transesophageal echocardiography showed a good position of the device, we decided to release it and to quickly retrieve as a unit into the right atrium both the delivery cable with attached thrombus and the delivery sheath. We discuss about periprocedural anticoagulation dosing and monitoring and the importance to have specific studies in the setting of LAAOP.