Value and indications of transesophageal echocardiography before cardioversion of atrial fibrillation

Transoesophageal echocardiography is essential for the diagnosis of left atrial thrombosis and its precursors (dense spontaneous contrast--reduced auricular emptying velocities) and for the diagnosis of complex aortic atheroma. The sensitivity and specificity of transoesophageal echocardiography for the diagnosis of left atrial thrombus are about 100% and about 90% for that of aortic atheroma. The formal indications for transoesophageal echocardiography before cardioversion are: atrial fibrillation complicated by stroke or a recent systemic embolism: atrial fibrillation complicated by mitral valve disease as the thrombo-embolic risk is major in this context: atrial fibrillation with a high thromboembolic risk: a history of stroke, presence of cardiac failure, diabetes, permanent hypertension, a very dilated left atrium (> or = 50 mm): apparently isolated atrial fibrillation for which long term anticoagulant therapy is hoped to be avoided. On the other hand, in recent, uncomplicated, non-valvular atrial fibrillation, a common fallacy should be corrected: transoesophageal echocardiography does not improve the safety of electrical cardioversion. With similar durations of prior anticoagulant therapy. Over a 3 week period, the frequency of thromboembolic complications is the same whether or not transoesophageal echocardiography is performed before cardioversion (0.8% in both groups of the SEIDL study). With short periods of anticoagulant therapy before cardioversion, there is a higher thromboembolic complication and mortality rate (ACUTE study). The safety of cardioversion is not related to the practice of prior transoesophageal echocardiography but to strict and efficacious anticoagulation for a period of 3 weeks before cardioversion.     

Critical appraisal of transesophageal echocardiography in cardioversion of atrial fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia and an important health concern in the United States because of the increasing aging population. Cardioversion of atrial fibrillation to sinus rhythm to relieve symptoms and to reduce the incidence of thromboembolism is now common practice. Recently, transesophageal echocardiography (TEE)-facilitated cardioversion emerged as an acceptable therapeutic alternative owing to the assumption that early cardioversion can obviate many of the concerns and disadvantages associated with the conventional approach. We review the current standing of TEE-facilitated early cardioversion vis-à-vis the salient cardioversion issues and its potential future role amid evolving cardioversion paradigms.     

The role of transesophageal echocardiography in atrial fibrillation

Transesophageal echocardiography (TEE) is very useful in the evaluation and management of selected patients with atrial fibrillation, primarily by clear visualization of left atrial appendage thrombus. Insights gained from two-dimensional and Doppler interrogation of the appendage include recognition of the association of dense spontaneous contrast and reduced mechanical appendage function with increased risk of thromboembolism. TEE-guided cardioversion has been shown to be safe and effective for a subset of patients, provided it is performed by experienced operators familiar with imaging the appendage and recognizing artifacts.     

Simultaneous transesophageal cardioversion and echocardiography: Feasibility and safety

BACKGROUND: Transesophageal echocardiography (TEE) is routinely used to exclude atrial thrombus prior to cardioversion of atrial fibrillation (AF). Because the TEE probe lies adjacent to the atria, cardioversion using an electrode attached to the TEE probe should allow for immediate low-energy transesophageal cardioversion. OBJECTIVE: The purpose of this study was to evaluate a cardioversion electrode sheath that can be affixed to conventional TEE probes for simultaneous thrombus exclusion and cardioversion of AF. METHODS: A thin electrode was integrated into a latex or polyurethane sheath covering a conventional TEE probe. TEE thrombus exclusion and biphasic transesophageal cardioversion using a step-up protocol were performed during deep sedation. Esophagoscopy was performed immediately after cardioversion and after 1 week. RESULTS: TEE was performed in 27 patients. One patient showed left atrial thrombi. Transesophageal cardioversion was successful in 25 of the remaining 26 patients. Mean atrial cardioversion threshold was 63 +/- 48 J. Transesophageal cardioversion restored sinus rhythm in two patients with unsuccessful transthoracic cardioversion. Transesophageal cardioversion in deep sedation was well tolerated. Esophagoscopy revealed slight mucosal damage in three patients at the site of shock application; two of these patients showed signs of gastroesophageal reflux disease. Mucosal damage unrelated to the site of shock delivery was noted in three patients. CONCLUSION: Atrial thrombus exclusion and transesophageal cardioversion of AF via a disposable cardioversion sheath offers the opportunity to perform transesophageal cardioversion and TEE thrombus exclusion during one sedation. It may not be suitable for use in patients with gastroesophageal reflux disease. Transesophageal cardioversion may establish sinus rhythm in selected patients refractory to transthoracic cardioversion.     

The value of transesophageal echocardiography for determination of tactics of cardioversion of atrial fibrillation

Transesophageal echocardiography was carried out in 110 patients before cardioversion of nonvalvular atrial fibrillation which duration exceeded 2 days. Twenty thrombi were found in 18 patients (16.4%). Anticoagulant phenindione was given to these patients for 3 weeks. Patients without thrombus received intravenously amiodarone followed with procainamide. Sinus rhythm was restored in 39.3% of these cases. In 5.5% of patients atrial fibrillation terminated spontaneously. Control transesophageal echocardiography showed that after 3 weeks there remained 11 atrial thrombi but all of them lost motility. Electrical cardioversion was successful in 90.7% of patients receiving short term and in 80% of patients receiving 3-week anticoagulant therapy (p>0.05). All patients received phenindione for 4 weeks after cardioversion. There were no thromboembolic or hemorrhagic complications. Ability of transesophageal echocardiography to detect atrial thrombi allows to carry out early cardioversion and to identify patients with high risk of embolism.