Right Atrial Appendage Function in Different Etiologies of Permanent Atrial Fibrillation: A Transesophageal Echocardiography and Tissue Doppler Imaging Study

Objectives: Several studies exist on the left atrial appendage function (LAA) in permanent atrial fibrillation (AF). However, knowledge about the right atrial appendage (RAA) function is limited. We investigated RAA function with TEE and tissue Doppler imaging (TDI) in permanent AF patients with different etiologies and evaluated predictive parameters of right atrial spontaneous echo contrast (SEC) and thrombi. Methods: Patients with permanent AF developed due to three different etiologies (20 mitral stenosis, 44 hypertension, 20 hyperthyroidism) and 23 subjects with sinus rhythm were included into the study. RAA was examined with TEE and pulsed‐wave and TDI velocities of RAA were measured. Results: Both PW‐Doppler and TDI velocities were significantly impaired in all AF groups compared to controls. The lowest velocities were recorded in mitral stenosis patients. Right atrial moderate–severe SEC was observed in 75% of the mitral stenosis patients, in 25% of hypertensive patients, and in 30% of hyperthyroidism patients. Right atrial thrombus was observed in 25% of mitral stenosis, 4.5% of hypertension, and in none of the hyperthyroidism patients. In the multivariate analysis, the most important parameter associated with the severity of RAA SEC was the percent change in RAA area (B =−0.034, P = 0.03). Conclusion: In patients with permanent AF, impairment of RAA function and development of right atrial SEC‐thrombus are closely related to the underlying etiology. These results suggested that evaluation of RAA functions may have an incremental value over the assessment of the LAA for determining thromboembolic risk. (Echocardiography 2010;27:384‐393)     

Right Atrial Appendage Thrombus Found in a Patient in Normal Sinus Rhythm with Normal Right Ventricular Systolic Function

A 79‐year‐old woman underwent transesophageal echocardiography to evaluate the severity of her mitral regurgitation prior to urgent bypass. Evaluation of the right‐sided chambers was notable for a mass in the right atrial appendage (RAA). Surgical excision and pathologic examination proved this to be a thrombus. This is the first reported case of a RAA thrombus in a patient with normal sinus rhythm and normal right ventricular (RV) function. It illustrates that complete transesophageal studies may sometimes demonstrate incidental findings, and that right atrial thrombus can (rarely) be found in patients in sinus rhythm with normal RV function.     

Simultaneous Right and Left Atrial Appendage Thrombus in a Patient with Atrial Fibrillation: A Lesson to Remember

We report a case of simultaneous right and left atrial appendage thrombi in a 76‐year‐old‐man with atrial fibrillation. Although transesophageal echocardiography is considered a routine diagnostic procedure, complete and comprehensive visualization of both atrial appendages is of paramount importance, particularly with the introduction of new therapeutic options like left atrial appendage exclusion devices. We expect to raise awareness among clinicians of the prevalence and implications of bilateral atrial appendage thrombi in common clinical practice.     

Low-Energy Internal Cardioversion for Atrial Fibrillation Resistant to External Cardioversion

Internal Cardioversion. introduction : This report describes the electrical conversion of atrial fibrillation in two morbidly obese patients refractory to external cardioversion at 360 J.
Methods and Results : The two patients were lightly sedated and underwent placement of decapolar catheters in the coronary sinus and right atrial appendage. All ten electrodes of each decapolar catheter were electrically coupled, and defibrillation was attempted at successively increasing levels using a biphasic decaying exponential waveform generated by an external defibrillator. Both patients were returned to normal sinus rhythm using <10 J without complication.
Conclusion : Internal cardioversion is effective in restoration of sinus rhythm in some patients refractory to conventional forms of therapy     

左心耳在预测心房颤动发生脑卒中的作用

成为公共健康沉重负担的心房颤动和相关的血栓栓塞性脑卒中事件仍在以惊人的速度增长。心房颤动导致脑卒中的风险增加了5倍．．因此,预防脑卒中的心房颤动管理仍然是最关键的一方面。现在公认的重点预防措施就是规范抗凝,包括已使用很广泛的华法林和现在出现的新抗凝药如利伐沙班等。而且抗凝药的使用已有据可查。由于左心耳在心房鲡动血栓的发生中起关键作用,所以有目的性地去除或结扎左心耳来预防发生脑卒中就成了一种可替代的治疗方法,尤其是适用于那些不适合口服抗凝药的患者,,现就左心耳预测心房颤动发生脑卒中进行介绍。     

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.     

Percutaneous Left Atrial Appendage Ligation for Stroke Prevention in Atrial Fibrillation

Prevention of thromboembolic complications in atrial fibrillation remains a tremendous clinical challenge. Knowledge that the left atrial appendage (LAA) is the most common anatomical origin of cardioembolic strokes1 has been the main motivation to develop clinical and procedural strategies to exclude the LAA from the circulation, either surgically or percutaneously. This review discusses the rationale behind these strategies, their relative merits, and future prospects for LAA exclusion strategies.     

左心耳封堵术在预防心房颤动患者脑卒中的研究进展

心房颤动是最为常见的心律失常之一,极易引起脑卒中事件。左心耳是血栓形成的主要部位,封堵左心耳可减少心房颤动血栓的发生率。现就封堵左心耳来预防心房颤动患者脑卒中的研究做一综述。     

左心耳结构复杂性与非瓣膜性心房颤动患者左心耳血栓形成的关系

目的:探讨左心耳结构复杂性与非瓣膜性心房颤动(NVAF)患者左心耳血栓形成的关系。方法:连续入选拟行射频消融术治疗的NVAF患者295例,记录病史资料和化验指标,进行CHA2DS2-VASc评分。行经食道超声心动图和计算机断层扫描血管造影(CTA)检查了解左心耳有、无血栓形成,以此将患者分为血栓组(n=42)和无血栓组(n=253)。应用CT影像后处理系统对左心房CTA影像进行三维重建,获取每例患者的左心耳形态,将左心耳形态分为单纯型和复杂型两类。分析左心耳血栓形成与各项潜在危险因素的关系。结果:血栓组非阵发性心房颤动(76.2%vs 18.2%)、复杂型左心耳比例(66.7%vs 45.1%)显著高于无血栓组(P均<0.01)。此外,血栓组患者的年龄、心房颤动病程、左心房前后径、B型利钠肽、血尿酸、CHA2DS2-VASc评分均大于无血栓组(P均<0.05)。相对于无血栓组,血栓组患者的高血压、糖尿病、冠心病、慢性心力衰竭、脑卒中/短暂性脑缺血发作/血栓栓塞以及血管疾病的患病率更高(P均<0.05)。多因素Logistic回归分析显示,复杂型左心耳(OR=4.129,95%CI:1.413~12.069)、心房颤动病程(OR=1.021,95%CI:1.006~1.036)、非阵发性心房颤动(OR=13.910,95%CI:4.563~42.406)与CHA2DS2-VASc评分(OR=2.580,95%CI:1.115~5.966)均是左心耳血栓形成的独立危险因素(P均<0.05)。结论:复杂型左心耳为NVAF患者左心耳血栓形成的独立危险因素。     

Resolution of Thrombi in Left Atrial Appendage Aneurysm

Atrial appendage aneurysm is a rare cardiac disease and may be complicated by embolic events and rhythm disturbances. We describe a case of a congenital left atrial aneurysm presenting with a cere-brovascular accident in a 57-year-old female. The diagnosis was made by transesophageal echocardiography, which revealed the presence of intraaneurysmal thrombi. The patient initially received anticoagulant therapy and the thrombi were resolved. Subsequently, she was successfully operated on and the aneurysm was removed. This is the first report of thrombi resolution in a left atrial appendage aneurysm.     

Internal Cardioversion of Persistent Atrial Fibrillation Using Rectilinear Biphasic Waveform

Internal electrical cardioversion is currently used in patients with persistent atrial fibrillation resistant to external electrical cardioversion. In external cardioversion, biphasic waveforms have shown a greater efficacy than monomorphic waveforms. The present study aimed to test the safety and efficacy of rectilinear biphasic waveform in converting patients with persistent atrial fibrillation to sinus rhythm using internal electrical cardioversion, and to compare it with that of classical monophasic waveform. Twenty-seven consecutive patients with persistent AF received 31 internal cardioversions, using monophasic waveform in 11 (group I), and rectilinear biphasic waveform in 20 cases (group II). Baseline patients characteristics were similar in both groups. Multipolar catheters were positioned in the distal coronary sinus and in the high right atrium. Synchronised shocks were delivered using an escalating protocol of 2, 5, 10, 15, 20, 30, and 50 Joules. In group I, 1 patient was resistant to maximal energy (success rate 91%). The mean energy of the maximal shock was 18 ± 13 J. In group II, all patients were converted to sinus rhythm. The mean energy of the maximal shock was 9 ± 5 J (p < 0.01 vs. group I). No significant complications occurred. At 3 months follow-up, 45% of group I and 60% of group II patients remained in sinus rhythm (p = NS).We conclude that internal cardioversion using rectilinear biphasic waveform is feasible and safe, and requires less energy than classical monophasic waveforms.     

The Left Atrial Appendage: Target for Stroke Reduction in Atrial Fibrillation

A patient with atrial fibrillation (AF) has a greater than 5% annual risk of major stroke, a 5-fold increase compared to the general population. While anticoagulation remains the standard stroke prevention strategy, the nature of lifelong anticoagulation inevitably carries an increased risk of bleeding, increased stroke during periods of interruption, increased cost, and significant lifestyle modification. Many patients with atrial fibrillation have had their left atrial appendage (LAA) ligated or excised by surgeons during cardiac surgery, a decision based largely on intuition and with no clear evidence of efficacy in stroke risk reduction. The observation that 90% of the thrombi found in nonvalvular AF patients and 57% found in valvular AF are in the LAA, triggered significant interest in the LAA as a potential therapeutic target. Until recently, the results were inconsistent, and high rates of incomplete occlusions precluded the medical community from confirming a definite relationship between LAA and stroke. As a result, anticoagulation is still the recommended first-line stroke risk reduction in AF, and the American College of Cardiology/American Heart Association guidelines recommend LAA exclusion only with surgical ablation of AF or in the context of concomitant mitral valve surgery.A handful of devices have been developed for LAA exclusion. This includes percutaneous options such as WATCHMAN™ Left Atrial Appendage Closure Device (Boston Scientific Corporation, Marlborough, MA), hybrid epicardial devices such as the LARIAT Suture Delivery Device (SentreHEART, Inc., Redwood City, CA), and epicardial surgical devices such as AtriClip® LAA Occlusion System (AtriCure, Inc., West Chester, OH). Studies of the Watchman device have shown noninferiority to Warfarin in stroke prevention and this device has recently gained approval from the U.S. Food and Drug Administration (FDA) following lengthy delays due to safety concerns. The Lariat device, which received 510K clearance by the FDA for tissue approximation but not LAA exclusion, has been the target of significant criticism due to serious procedural safety concerns and high incomplete closure rates. The surgical AtriClip has been FDA approved since 2009 and is currently the most widely used LAA exclusion device placed through an epicardial approach. Small studies have shown excellent reliability and success of complete LAA closure with the AtriClip device, which is implanted through an epicardial approach. Currently, we are conducting a multicenter trial to demonstrate the stroke prevention potential of this epicardial device through a short (45 minute), stand-alone, minimally invasive procedure in lieu of lifelong anticoagulation in patients at high risk of bleeding.     

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.     

CT定量评价左心耳解剖结构与心房颤动射频消融术后复发的相关性研究

目的:采用256层螺旋CT定量评价左心耳解剖结构与心房颤动(房颤)射频消融术后复发的关系。方法:研究纳入83例首次进行射频消融术的房颤患者,平均年龄(60.36±10.11)岁,男性49例(59.04%)。所有患者术前均行256层螺旋CT检查,测量左心房体积、左心耳体积、左心耳开口周长、短径、长径、深径并收集患者临床资料。83例房颤患者行射频消融术后中位随访时间19(4~24)个月,27例(32.53%)患者复发。根据有无复发分为复发组(n=27例)和未复发组(n=56例)。结果:对83例患者的临床资料进行分析,复发组持续性房颤患者及心力衰竭(心衰)患者较未复发组比例更高,CHA2DS2-VASc评分更高(P均<0.05);对左心耳解剖结构分析,左心房体积、左心耳体积、左心耳开口周长、短径、长径、深径,复发组均大于未复发组(P均<0.05);多因素Cox比例风险回归分析显示较大的左心耳体积是房颤复发的独立预测因子(HR=1.160,95%CI:1.095~1.229,P<0.001);左心耳体积>9.25 ml对射频消融术后复发具有一定预测价值,敏感度85.2%、特异度67.9%、AUC 0.82,房颤复发率较高(P<0.00l)。结论:房颤会造成心脏结构重构,左心耳各解剖径线明显增大可能是房颤射频消融术后复发的原因,并且发现左心耳体积增大是房颤射频消融术后复发的独立预测因子。     

Real Time Three-Dimensional Transesophageal Echocardiography-Guided Placement of Left Atrial Appendage Occlusion Device

real time three-dimensional transesophageal echocardiography (3D TEE) is a novel imaging technique whose full utility is still being evaluated. We present a case utilizing 3D TEE for percutaneous placement of a left atrial appendage occlusion device. This evolving technology has potential application in other cardiovascular interventional procedures.