非瓣膜病心房颤动病人电复律前后左心房功能变化研究

目的评价经食道超声心动图(TEE)对非瓣膜病心房颤动(房颤)病人电复律前后左心房功能变化.方法选择房颤持续2周以上的非瓣膜疾病病人18例,其中原发性高血压6例,扩张型心肌病6例,脑血栓4例,缺血性心肌病2例.应用TEE确定左心房内无血栓后行电复律,转为窦性心律者测定左心耳血流最大速度及流速积分,肺静脉血流最大速度及流速积分、二尖瓣血流最大速度、流速积分及减速时间.结果左心耳排空速度于复律后显著减少,有显著性差异(P＜0.05),排空指数增加(P＞0.05),电复律后肺静脉收缩期、舒张期最大流速及其流速积分比值无显著差异(P＞0.05),收缩期最大流速积分在左、右肺静脉均有显著差异(P均＜0.05).复律前后舒张期最大流速积分在右肺静脉有显著性差异(P＜0.05),左肺静脉差异不显著(P＞0.05).二尖瓣血流E波最大速度及E波与A波比值(E/A)增加.结论适合的抗凝治疗及TEE确认心房内无附壁血栓后进行电复律治疗,安全又无并发症.TEE能评价房颤病人电复律后的左心房功能变化.电复律后心房的电活动及机械活动均微弱,能引起左心房功能不全及栓塞,所以心房功能完全恢复前均有必要进行抗凝治疗.     

Cardioversion under the guidance of transesophageal echochardiograhy in persistent atrial fibrillation: results with low molecular weight heparin

BACKGROUND: Transesophageal echocardiography (TEE) guided cardioversion to restoration of sinus rhythm is a therapeutic option in patients with atrial fibrillation (AF). Anticoagulation at the time of and after cardioversion is necessary to prevent formation of new thrombus during atrial stunning period. We aimed to evaluate the efficacy and safety to TEE guided cardioversion with low molecular weight heparin (LMWH) in patients with atrial fibrillation. METHODS: We followed up 208 patients with persistent AF (mean age: 65.5+/-10.2 years) who were attempted TEE guided cardioversion. LMWH were used as an anticoagulant and warfarin therapy was continued. RESULTS: Cardioversion were performed in 183 patients. Sinus rhythm restored in 144 patients (78.7%). Mean follow up duration was 155 days. No cardiac death occurred. In the early follow up period (within 30 day) one thromboembolic event (0.54%) occurred in a patient who was cardioverted. Two patients who had not been cardioverted because of left atrial thrombus presented embolic stroke, one in early and another in late follow up period. All embolic complications occurred in patients who had been taking warfarin and whose INR level was subtherapeutic at the time of stroke. Sinus rhythm was maintained in 64% and total hemorrhagic complications occurred in 4.8% of the patients in long-term follow-up. CONCLUSION: TEE guided cardioversion with a short-term anticoagulation protocol using low molecular weight heparin is a safe and effective method in restoring and maintaining sinus rhythm and enables us to make earlier cardioversion in atrial fibrillation.     

Transesophageal echocardiography-guided approach to cardioversion of atrial fibrillation

In patients with atrial fibrillation, electrical cardioversion is often performed to relieve symptoms, to improve left ventricular function, and to decrease throm-boembolic risks. However, cardioversion of atrial tachyarrhythmias is associated with an increased embolic risk, with an event rate of up to 5.6%. The American College of Chest Physicians recommend 3 weeks of systemic anticoagulation before elective cardioversion and 4 weeks of systemic anticoagulation afterwards. Expulsion of preexisting left atrial (LA) thrombi with resumption of sinus rhythm has traditionally been considered the mechanism for this increased embolic risk associated with cardioversion. The advent of transesophageal echocardiography (TEE) has allowed accurate detection of LA thrombus. Moreover, recent studies using TEE have identified a state of atrial “stunning” immediately after cardioversion, which is considered a thrombogenic milieu in which new thrombus formation and increased or de novo appearance of LA spontaneous echocardiographic contrast have been observed. Furthermore, embolic events have been reported after cardioversion despite exclusion of preexisting LA thrombus by TEE. These studies strongly suggest an alternative mechanism for embolism after cardioversion, ie, atrial stunning with worsened atrial appendage function and enhanced thrombogenesis. Recent studies have shown the safety of a TEE-guided anticoagulation approach in which exclusion of preexisting LA thrombus by TEE enables early cardioversion without the need for the standard 3 weeks of systemic anticoagulation. The importance of maintaining therapeutic anticoagulation has been further emphasized. Although preliminary observational studies of TEE-guided cardioversion are encouraging, there has been no prospective, randomized trial comparing the two strategies of anticoagulation management. The Assessment of Cardioversion Utilizing Transesophageal Echocardiography (ACUTE) pilot study randomized 126 patients from 10 sites and showed the feasibility and safety of the larger scale study. A larger multicenter, prospective randomized trial is now underway and is expected to randomize a total of 3,000 patients. The results of the ACUTE study will definitively establish the safest and the most cost-effective way to manage anticoagulation for elective cardioversion.     

Atrial fibrillation and cardioversion: role of transesophageal echocardiography]

The most common cardiac arrhythmia is atrial fibrillation (AF). Echocardiography has been an important tool in the evaluation of patients with AF. Transesophageal echocardiography (TEE) offers excellent visualization of the atria and accurate identification or exclusion of atrial thrombi. Patients undergoing cardioversion are treated conventionally with therapeutic anticoagulation for 3 weeks before and 4 weeks after cardioversion to decrease the risk of thromboembolism. A TEE-guided strategy has been proposed as an alternative that may lower stroke and bleeding events. Patients without atrial thrombus by TEE are cardioverted on achievement of therapeutic anticoagulation, whereas cardioversion is delayed in patients with any thrombus. The two management strategies comparably lower the patient's embolic risk when the guidelines are properly followed. The TEE-guided approach offers the advantage of simplified anticoagulation management and may lower the incidence of bleeding complications.     

Embolic events in patients with atrial fibrillation and effective anticoagulation: value of transesophageal echocardiography to guide direct-current cardioversion. Final results of the Ludwigshafen Observational Cardioversion Study

OBJECTIVES: The primary objective was to evaluate the usefulness of transesophageal echocardiography (TEE)-guided cardioversion to prevent thromboembolic complications in patients with atrial fibrillation (AF) and effective anticoagulation (International Normalized Ratio of 2 or 3) at least three weeks before cardioversion. BACKGROUND: Transesophageal echocardiography has been proposed as a method of screening patients for left atrial thrombi before direct-current cardioversion of AF. The usefulness of TEE as a screening tool has always been evaluated in patients without long-term anticoagulation before cardioversion. METHODS: This prospective, single-center, observational study, performed on an intention-to-cardiovert basis, comprised 1,076 consecutive, unselected patients with AF. The initial two years were designed to be the control phase, during which the conventional approach was used. After that, cardioversion guided by TEE was performed in consecutive patients. RESULTS: The prevalence of left atrial thrombi was 7.7% in patients with persistent AF and effective anticoagulation. During the first four weeks after electrical cardioversion, six thromboembolic complications were observed in patients in whom the TEE-guided approach was employed (6 [0.8%] of 719 patients), compared with three thromboembolic complications in patients in whom the conventional approach was used (3 [0.8%] of 357 patients). None of the patients in whom electrical cardioversion was not performed experienced an embolic event. CONCLUSIONS: There were no differences in the rate of embolic events between the two treatment groups. In patients with AF and effective anticoagulation, TEE-guided electrical cardioversion does not reduce the embolic risk. However, TEE revealed left atrial thrombi in 7.7% of patients with AF and effective anticoagulation, before direct-current cardioversion.     

Role of transesophageal echocardiography-guided cardioversion of patients with atrial fibrillation.

Electrical cardioversion of patients with atrial fibrillation (AF) is frequently performed to relieve symptoms and improve cardiac performance. Patients undergoing cardioversion are treated conventionally with therapeutic anticoagulation for three weeks before and four weeks after cardioversion to decrease the risk of thromboembolism. A transesophageal echocardiography (TEE)-guided strategy has been proposed as an alternative that may lower stroke and bleeding events. Patients without atrial cavity thrombus or atrial appendage thrombus by TEE are cardioverted on achievement of therapeutic anticoagulation, whereas cardioversion is delayed in higher risk patients with thrombus. The aim of this review is to discuss the issues and controversies associated with the management of patients with AF undergoing cardioversion. We provide an overview of the TEE-guided and conventional anticoagulation strategies in light of the recently completed Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) clinical trial. The two management strategies comparably lower the patient's embolic risk when the guidelines are properly followed. The TEE-guided strategy with shorter term anticoagulation may lower the incidence of bleeding complications and safely expedite early cardioversion. The inherent advantages and disadvantages of both strategies are presented. The TEE-guided approach with short-term anticoagulation is considered to be a safe and clinically effective alternative to the conventional approach, and it is advocated in patients in whom earlier cardioversion would be clinically beneficial.     

Effect of Direct Current Shocks on Left Atrial Mechanical Function in Patients With Structural Heart Disease

Objectives. This study examined the effect of endocardial and transthoracic direct current (DC) shocks on left atrial and left atrial appendage function in humans with structural heart disease.Background. DC cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial and left atrial appendage dysfunction and the development of spontaneous echo contrast (SEC). This phenomenon has been termed atrial “stunning” and may be associated with thrombus formation and embolic stroke. To what extent the shock itself contributes to atrial stunning is unclear.Methods. Thirteen patients in sinus rhythm undergoing implantation of a ventricular implantable cardioverter defibrillator (ICD) were prospectively evaluated. All patients had significant structural heart disease. To evaluate the effects of DC shocks on left atrial and left atrial appendage function, biphasic R wave synchronized endocardial shocks of 1, 10 and 20 J were delivered between the right ventricular electrode and the left pectoral generator of the ICD in sinus rhythm. R wave synchronized transthoracic shocks of 360 J were also delivered between anteriorly and posteriorly positioned chest electrodes. Transesophageal echocardiography was performed to evaluate left atrial appendage velocities, mitral inflow velocities and the presence of SEC before and immediately after each DC shock.Results. There were no significant changes in left atrial or left atrial appendage function after endocardial or transthoracic DC shocks. Left atrial SEC did not develop after endocardial or transthoracic DC shocks.Conclusions. Endocardial and transthoracic DC shocks are not directly responsible for left atrial and left atrial appendage stunning and do not contribute to the stunning that is observed after the cardioversion of AF to sinus rhythm.     

Utility of transesophageal echocardiography in identification of thrombogenic milieu in patients with atrial fibrillation (an ACUTE ancillary study)

The ACUTE trial randomly assigned patients who had atrial fibrillation (AF) of >2 days' duration to a transesophageal echocardiographically guided or a conventional strategy before cardioversion. In the 571 patients who underwent transesophageal echocardiography (TEE) in the ACUTE trial, we assessed the relative predictive value of baseline data derived by history, transthoracic echocardiography, and TEE for prediction of thrombus and adjudicated embolism (thromboembolism) as a composite end point. TEE was performed at 70 centers in 571 patients, 549 in the transesophageal echocardiographically guided group and 22 crossovers in the conventional group. Six patients (1.1%) who had embolism and 79 (13.8%) who had thrombi were identified in this group. Thrombus was completely resolved in 76.5% of patients who had repeat transesophageal echocardiographic procedures after 31.7 +/- 7.5 days of anticoagulation. For patients who had embolic events, none had a transesophageal echocardiographically identified thrombus; 5 of 6 (83.3%) had >/=1 transesophageal echocardiographic risk factors (including spontaneous echocardiographic contrast, aortic atheroma, patent foramen ovale, atrial septal aneurysm, mitral valve strands), and 4 of 6 (66.66%) had subtherapeutic anticoagulation or no anticoagulation. Clinical, transthoracic echocardiographic, and transesophageal echocardiographic risk factors contributed significantly to the prediction of composite thrombus/embolism. However, transesophageal echocardiographic thromboembolic risk factors were the strongest predictors of thromboembolism and provided statistically significant incremental value (chi-square 38.0, p <0.001) for identification of risk. Thus, in addition to thrombus identification, TEE has significant incremental value in the identification of patients who had high thromboembolic risk. In conclusion, this study supports the role of TEE and anticoagulation monitoring in patients who have atrial fibrillation and is useful for identifying thromboembolic risk factors.     

房间隔缺损并发心房纤颤患者应用Amplatzer伞封堵房缺后心房纤颤的电复律治疗

目的 :初步评价房间隔缺损并发心房纤颤患者应用 Am platzer伞封堵房间隔缺损后心房纤颤的电复律疗效。方法 :2例患者 （5 1～ 5 3岁 ）。在透视及食管超声心动图监视下经导管置入 Amplatzer伞封堵房间隔缺损。术后即时行超声心动图 ,术后 2 4h,和 1,3,6月 ,分别行经胸超声心动图评价房间隔缺损治疗效果。术后 6月行电复律。结果 :2例患者疗效均佳 ,房间隔未见残余分流 ,电复律成功 ,患者转为窦性心律 ,复律后无并发症及 Amplatzer伞移位。结论 :应用 Am platzer伞封堵房间隔缺损并发心房纤颤患者 ,电复律易成功 ,是一种安全有效的复律方法。     

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.     

Is Transesophageal Echocardiography Necessary before D.C. Cardioversion in Patients with a Normal Transthoracic Echocardiogram?

PURPOSE: Transesophageal echocardiography has emerged as an accepted approach before D.C. cardioversion for atrial fibrillation. The frequency of atrial thrombi detected on transesophageal echocardiography has varied from 7% to 23%. Many patients undergoing transesophageal echocardiography have had a previous transthoracic echocardiogram. Though transthoracic echocardiography has a low yield for the detection of intracardiac thrombi, it is highly accurate in diagnosing a structurally abnormal heart. The purpose of this study was to assess the frequency of thrombi detected by transesophageal echocardiography in patients with an entirely normal transthoracic echocardiogram and hence the advocacy of a selective approach in performing transesophageal echocardiography in patients undergoing D.C. cardioversion for atrial fibrillation. METHODS: 112 consecutive patients with atrial fibrillation who had undergone transesophageal echocardiography before D.C. cardioversion were evaluated. They all had a transthoracic echocardiogram within the 2 months preceding their transesophageal echocardiogram. Based on their transthoracic echocardiographic study, they were divided into two groups: Group 1 consisted of patients with a normal transthoracic echocardiogram and Group 2, those with an abnormal study. RESULTS: Thrombi or spontaneous echo contrast were found in 14 of 112 patients (16%). All however were detected in Group 2 patients. There was no patient with a normal transthoracic echocardiogram who had thrombus on his/her transesophageal echocardiogram. CONCLUSIONS: Our results suggest that a selective approach may be exercised in the use of transesophageal echocardiography prior to D.C. cardioversion for atrial fibrillation. Patients with an entirely "normal" transthoracic echocardiogram may proceed directly to cardioversion without a precardioversion transesophageal echocardiogram.     

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.     

Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance

OBJECTIVES: The study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu. BACKGROUND: Recent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl. METHODS: Between 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h. RESULTS: We performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu. CONCLUSIONS: The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.     

Transesophageal echocardiography in electrical cardioversion: Is it possible to predict conversion to sinus rhythm?]

Due to its ability to safely exclude thrombi, transesophageal echocardiography (TEE) is now routinely performed in patients proposed for electrical cardioversion. However, what is the value of TEE in predicting conversion to sinus rhythm in patients with atrial fibrillation (AF)? To answer this question, TEE was performed in 21 patients with chronic AF before elective cardioversion. Patients were divided in two groups according to the outcome of cardioversion: Group A--Restoration of sinus rhythm achieved: Group B--atrial fibrillation persisted. The echocardiographic variables used to compare both groups were 1--Left Atrial size; 2--Left Atrial Appendage (LAA) systolic and diastolic dimensions; 3--LAA emptying and filling velocities; 4--LAA emptying fraction; 5--Presence of LAA spontaneous contrast. The clinical variable evaluated was 6--therapy with oral amiodarone for more than 2 weeks (> or = 200 mg/day). The results of this study showed that patients with smaller LA, adequately treated with amiodarone and with higher LAA emptying and filling velocities, have the greatest probability of conversion to sinus rhythm.     

Atrial Mechanical Function Before and After Electrical or Amiodarone Cardioversion in Atrial Fibrillation: Assessment by Transesophageal Echocardiography and Pulsed Doppler

In some patients with atrial fibrillation (AF), it has been suggested that left atrial mechanical dysfunction can develop after successful electrical cardioversion, justifying postcardioversion anticoagulant treatment. The purpose of this study was to investigate differences in left atrial appendage peak flow velocities and the incidence of left atrial spontaneous echo contrast in patients with AF before and after electrical cardioversion or intravenous amiodarone, studied using transesophageal echocardiography (TEE) and pulsed Doppler. We performed a control TEE in 7 patients in the electrical group and 6 in the amiodarone group, with no significant clinical differences between both groups. A second TEE was performed immediately in the 7 patients with successful electrical cardioversion. The peak flow velocities in the appendage before and after the procedure were: filling 43.3 ± 22 vs 27.7 ± 28 cm/sec (P = 0.01) and emptying 35.5 ± 22 vs 23.6 ± 17 cm/sec (P = 0.01), respectively. The spontaneous echo contrast increased in 4 of the 7 patients. In 4 patients of the amiodarone group, the peak flow velocities in the appendage during AF and within the first 24 hours after restoration of sinus rhythm were: filling 37.4 ± 12 vs 37.8 ± 18 cm/sec and emptying 36.4 ± 18 vs 35.9 ± 18 cm/sec, respectively (P = NS). There was no change in spontaneous echo contrast. In conclusion, patients with AF reverted to sinus rhythm using amiodarone did not show changes in left atrial mechanical function; however, patients with electrical cardioversion showed mechanical dysfunction. Further investigations on the effects of amiodarone and other drugs on the mechanical function of the atria are needed to determine if patients reverted pharmacologically require antico-agulation post reversion.     

The D-dimer assay: a possible tool in the evaluation of atrial thrombosis

Atrial fibrillation (AF) is a common arrhythmia seen in clinical practice, and affects more than 4% of the population older than 60 years of age. Peripheral thromboembolism contributes significantly to the observed morbidity and mortality. Symptomatic AF, before cardioversion to normal sinus rhythm, requires either exclusion of atrial thrombi using transesophageal echocardiography (TEE) or the conventional use of three weeks of adequate anticoagulation. The exclusion of atrial thrombi by TEE, a nontomographic technique but comparable with conventional treatment of AF in outcomes, has inherent limitations due to the complex three-dimensional multilobed anatomy of the left atrial appendage, where the majority of atrial thrombi arise. Also, the conventional treatment of three weeks of therapeutic anticoagulation before cardioversion reportedly does not always eliminate atrial thrombi. Plasma D-dimer constitutes an antigen-antibody reaction to the dimeric final degradation product of a mature clot. An elevated fibrin D-dimer has a high sensitivity for intravascular thrombosis and, hence, may improve the evaluation of a patient with AF before cardioversion in addition to a TEE. A case is presented in which a positive D-dimer resulted in performing TEE to document atrial thrombosis and the complications of previous bacterial endocarditis. In the present case, this involved aortic root abscess formation and acute aortic regurgitation because of flailing of the noncoronary cusp that resulted in recurrent pulmonary edema.     

Transesophageal echocardiography before and during direct current cardioversion of atrial fibrillation: Evidence for “atrial stunning” as a mechanism of thromboembolic complications

Objectives. The purpose of this study was to evaluate the usefulness of transesophageal echocardiography before electrical cardioversion in patients with atrial fibrillation and to determine the mechanism of thromboembolism after cardioversion.Background. Thromboembolic complications after electrical cardioversion of atrial fibrillation have been attributed to the dislodgment of preexistent left atrial thrombus during the resumption of atrial contraction. Transesophageal echocardiography has been proposed as a method of screening patients for left atrial thrombus before cardioversion.Methods. Seventy transesophageal echocardiographic studies were performed in 66 patients, predominantly with nonvalvular atrial fibrillation, before direct current cardioversion. In addition, transesophageal echocardiography was performed during the cardioversion procedure in 15 patients and immediately after in 1 patient.Results. Left atrial thrombus was detected in one patient (1.4%), and cardioversion was canceled. Thromboembolic complications occurred in 4 patients, none of whom had evidence of left atrial thrombus before cardioversion. Within 10 s of successful cardioversion, left atrial spontaneous echo contrast appeared in five patients, increased in one patient and was unchanged in nine patients. Patients with new or increased spontaneous echo contrast had more impaired atrial contraction and slower initial heart rates after cardioversion than those without. Left ventricular contraction was also impaired transiently by cardioversion.Conclusions. Transesophageal echocardiographic detection of left atrial thrombus before direct current cardioversion is important but infrequent in patients with predominantly nonvalvular atrial fibrillation. The occurrence of thromboembolic complica tions in the absence of demonstrable left atrial thrombus and the new development of spontaneous echo contrast in association with the transient atrial dysfunction (“stunning”) caused by cardioversion suggest that cardioversion may promote new thrombus formation, in which case all patients should receive full anticoagulant therapy at the time of cardioversion.     

Stratification of thromboembolic risk of atrial fibrillation by transthoracic echocardiography and transesophageal echocardiography: The relative role of left atrial appendage function, mitral valve disease, and spontaneous echocardiographic contrast

The role of transesophageal echocardiography (TEE) in thromboembolic risk stratification in atrial fibrillation (AF) has not been established. Left atrial appendage contractile dysfunction in patients with AF predisposes to thrombus formation. The extent of blood stasis and propensity for thrombus can be assessed during TEE by measurement of the peak Doppler velocity of blood outflow from the appendage. Spontaneous echocardiographic contrast (SEC) is a swirling pattern of blood echogenicity that may be detected by TEE in the left atrium in patients with AF. The presence of SEC reflects left atrial blood stasis and a prothrombotic state. SEC is associated with an increased risk of systemic thromboembolic events. Parameters derived from TEE may provide additional prognostic data to clinical history and transthoracic echocardiography in thromboembolic risk stratification in AF.     

Course of intraatrial thrombi resolution using transesophageal echocardiography

Thromboembolic events are associated with atrial fibrillation and with cardioversion to sinus rhythm. Although studies have demonstrated the risk of this complication is reduced by a 3-week period of anticoagulation prior to cardioversion, limited data have suggested a longer period of anticoagulation is necessary for thrombus resolution. We identified and followed 25 patients noted to have intraatrial thrombi on an initial transesophageal echocardiogram (TEE) who subsequently had a follow-up TEE. The majority of patients had a single thrombus, often but not uniformly located in the left atrial appendage with the largest found in those patients with mitral stenosis. Repeat TEE was performed at a mean of 4 +/- 6 months and persistent thrombus was noted in 19 of 25 patients (76%). Seven of 19 patients with persistent thrombi were cardioverted and one of these patients had a neurologic event following the procedure (14%). The only findings associated with persistent thrombus were the presence of mitral valve disease and atrial fibrillation. Our findings suggest that intraatrial thrombi do not generally resolve following several weeks of anticoagulation and that persistent left-sided intraatrial thrombi may be associated with an increased risk for events following cardioversion. Given that a TEE-guided approach to cardioversion is being utilized more frequently, it may be important to determine thrombus characteristics on follow-up that would be predictive of embolic events following cardioversion.     

Incidence and Predictors of Left Atrial Thrombus Prior to Catheter Ablation of Atrial Fibrillation

Background: Transesophageal echocardiography (TEE) is commonly used prior to catheter ablation of atrial fibrillation (AF) in order to exclude left atrial (LA) thrombus. However, the incidence and predictors of LA thrombus detected with TEE have not been systematically examined in this setting.
Methods: This study included 732 cases (mean age 57 ± 11 years; 23% female; 353 persistent AF) in 585 consecutive patients referred for catheter ablation of AF. Patients were anticoagulated for at least 4 weeks prior to the procedure and then bridged with enoxaparin. TEE was performed in all cases within 24 hours prior to ablation.
Results: Preprocedural TEE revealed LA thrombus in 12 of 732 cases (1.6%), all located in the LA appendage. Among these 12 patients, 9 had persistent AF and 3 had paroxysmal AF. All patients with thrombus had an LA size ≥ 4.5 cm. LA thrombus was present in 0.3%, 1.4%, and 5.3% of patients with CHADS₂ scores of 0, 1, and ≥ 2, respectively. In multivariate analysis, a CHADS₂ score ≥ 2 and larger LA diameter remained significant predictors of LA thrombus.
Conclusions: Despite oral anticoagulation treatment, there is a small but significant incidence of LA thrombus by TEE prior to AF ablation. A CHADS₂ score ≥ 2 and larger LA diameter are independent predictors of LA thrombus in this patient population, while type of AF or rhythm at the time of TEE is not. The risk of LA thrombus is low in patients with a CHADS₂ score of 0 and in patients with an LA diameter < 4.5 cm.