Cardioversion guided by transesophageal echocardiography: the ACUTE Pilot Study. A randomized, controlled trial. Assessment of Cardioversion Using Transesophageal Echocardiography

Identifying Patients at High Risk of Left Atrial Appendage Thrombus Before Cardioversion: The CLOTS-AF Score

Background Transesophageal echocardiography-guided direct cardioversion is recommended in patients who are inadequately anticoagulated due to perceived risk of left atrial appendage thrombus (LAAT); however, LAAT risk factors remain poorly defined. Methods and Results We evaluated clinical and transthoracic echocardiographic parameters to predict LAAT risk in consecutive patients with atrial fibrillation (AF)/atrial flutter undergoing transesophageal echocardiography before cardioversion between 2002 and 2022. Regression analysis identified predictors of LAAT, combined to create the novel CLOTS-AF risk score (comprising clinical and echocardiographic LAAT predictors), which was developed in the derivation cohort (70%) and validated in the remaining 30%. A total of 1001 patients (mean age, 62±13 years; 25% women; left ventricular ejection fraction, 49.8±14%) underwent transesophageal echocardiography, with LAAT identified in 140 of 1001 patients (14%) and dense spontaneous echo contrast precluding cardioversion in a further 75 patients (7.5%). AF duration, AF rhythm, creatinine, stroke, diabetes, and echocardiographic parameters were univariate LAAT predictors; age, female sex, body mass index, anticoagulant type, and duration were not (all P>0.05). CHADS2VASc, though significant on univariate analysis (P<0.001), was not significant after adjustment (P=0.12). The novel CLOTS-AF risk model comprised significant multivariable predictors categorized and weighted according to clinically relevant thresholds (Creatinine >1.5 mg/dL, Left ventricular ejection fraction <50%, Overload (left atrial volume index >34 mL/m2), Tricuspid Annular Plane Systolic Excursion (TAPSE) <17 mm, Stroke, and AF rhythm). The unweighted risk model had excellent predictive performance with an area under the curve of 0.820 (95% CI, 0.752-0.887). The weighted CLOTS-AF risk score maintained good predictive performance (AUC, 0.780) with an accuracy of 72%. Conclusions The incidence of LAAT or dense spontaneous echo contrast precluding cardioversion in patients with AF who are inadequately anticoagulated is 21%. Clinical and noninvasive echocardiographic parameters may identify patients at increased risk of LAAT better managed with a suitable period of anticoagulation before undertaking cardioversion.

Transesophageal Echocardiogram Before Cardioversion in Atrial Fibrillation Patients

Transesophageal echocardiography (TEE) offers an invaluable, non-invasive avenue for diagnosing and managing various cardiac conditions, including atrial fibrillation (AF). As the most common cardiac arrhythmia, AF affects millions and can lead to severe complications. Cardioversion, a procedure to restore the heart's normal rhythm, is frequently conducted on AF patients resistant to medication. Due to inconclusive data, TEE's utility prior to cardioversion in AF patients remains ambiguous. Understanding TEE's potential benefits and limitations in this population could significantly influence clinical practice. This review aims to scrutinize the current literature on the use of TEE before cardioversion in AF patients. The principal objective is to understand TEE's potential benefits and limitations comprehensively. The study seeks to offer a clear understanding and practical recommendations for clinical practice, thereby improving the management of AF patients before cardioversion using TEE. A literature search of databases was conducted using the keywords "Atrial Fibrillation," "Cardioversion" and "Transesophageal echocardiography," resulting in 640 articles. These were narrowed to 103 following title and abstract reviews. After applying exclusion and inclusion criteria with a quality assessment, 20 papers were included: seven retrospective studies, 12 prospective observational studies, and one randomized controlled trial (RCT). Stroke risk associated with direct-current cardioversion (DCC) potentially results from post-cardioversion atrial stunning. Thromboembolic events occur post cardioversion, with or without prior atrial thrombus or cardioversion complications. Generally, cardiac thrombus localizes in the left atrial appendage (LAA), a clear contraindication to cardioversion. Atrial sludge without LAA thrombus in TEE is a relative contraindication. TEE before electrical cardioversion (ECV) in anticoagulated AF individuals is uncommon. In AF patients planned for cardioversion, contrast enhancement facilitates thrombus exclusion in TEE images, reducing embolic events. Left atrial thrombus (LAT) frequently occurs in AF patients, necessitating TEE examination. Despite the increased use of pre-cardioversion TEE, thromboembolic events persist. Notably, patients with post-DCC thromboembolic events had no LA thrombus or LAA sludge. The use of TEE-guided DCC has grown due to its ability to detect atrial thrombi pre-cardioversion, aiding risk stratification. Thrombus in the left atrium also signals an elevated risk of future thromboembolic events in AF patients. While atrial stunning post cardioversion detected by TEE is a significant risk factor for future thromboembolic events, further evidence is required. Therapeutic anticoagulation is essential during and post cardioversion, even if no atrial thrombus is detected. Current data recommends cardioversion guided by TEE, particularly in outpatient settings.

Cardiac CT angiography after percutaneous left atrial appendage closure: early versus delayed scanning after contrast administration

PURPOSE

Cardiac computed tomography angiography (CCTA) is increasingly used for device surveillance after left atrial appendage closure (LAAC). While CT protocols with delayed scans are useful to diagnose thrombus in the LAA, an optimal protocol for post-procedural CCTA has not been established. Therefore, we assessed the role of delayed versus early scans for device surveillance.

METHODS

We retrospectively reviewed patients who underwent LAAC at Vancouver General Hospital who had follow-up CCTAs using standard (early) and delayed scans. Scans were performed on Toshiba 320-detector (Aquilion ONE). Image quality was interpreted by 2 independent observers for anatomy, LAA contrast patency, and device-related thrombus (DRT) using VitreaWorkstationTM. A Likert scale of 1-5 was used (1= poor quality, 5= excellent) for assessment.

RESULTS

We included 27 consecutive LAAC patients (9 Amplatzer, 18 WATCHMAN) with mean age 76.0±7.7 years, mean CHADS2 score 2.8±1.3, CHA2DS2-VASc score 4.4±1.6 and HAS-BLED score 3.4±1.0. Subjective quality assessments by both reviewers favored early scans for assessment of anatomy (reviewer 1: 4.63±0.63 [early] vs. 1.74±0.71 [delayed]; reviewer 2: 4.63±0.63 [early] vs. 1.89±0.64 [delayed]) and DRT (reviewer 1: 4.78±0.42 [early] vs. 3.11±1.16 [delayed]; reviewer 2: 4.70±0.47 [early] vs. 3.04±1.29 [delayed]). Inter-rater variability showed good correlation between reviewers (intraclass correlation 0.61-0.95). Mean LAA/LA attenuation ratios were significantly different between scans, with larger mean percent reduction of contrast opacification from LA to LAA in the early scans (57.0±36.6% reduction for early vs. 29.1±30.8% for delayed; p < 0.001) CONCLUSION: For CT device surveillance post-LAAC early phase imaging provides superior image quality objectively and subjectively compared with delayed scanning.

Severe tricuspid bioprosthetic valve stenosis as an unusual cause of pulmonary embolism: a case report

Background 

Bioprosthetic tricuspid valve stenosis (TS) is an uncommon and frequently under-diagnosed condition. Although the resulting right heart failure symptoms are well-known, the associated thrombogenic potential is under-recognized.

Case summary 

A 44-year-old woman with bioprosthetic tricuspid valve (TV) replacement in 2001 was referred for urgent consultation due to acute worsening of dyspnoea and severe swelling and pain in her left arm and neck. She was diagnosed with atrial fibrillation 6 months before the presentation and was found to have right atrial (RA) thrombus with pulmonary embolism and extensive retrograde venous extension 1 month prior. Review of studies done at her local institution revealed 10 mmHg mean gradient (MG) across the bioprosthetic TV that was only reported as mild–moderate TS. Echocardiography done at our instruction confirmed suspicion of severe TS with calcified immobile leaflets. Computed tomography showed persistent RA thrombus and therefore surgical replacement of the TV was undertaken. Subsequently, patient’s dyspnoea rapidly improved.

Discussion 

Progressive dyspnoea and symptoms of right heart failure in a patient with a history of bioprosthetic TV replacement should be investigated for prosthetic valve dysfunction. Due to its rarity, TS diagnosis can be overlooked on routine echocardiography. In our patient, despite a measured MG of 10 mmHg, the presence of critical TS was not initially recognized. As TS is associated with increased thrombogenic potential and given the rare occurrence of in situ RA thrombosis, physicians must have a high index of suspicion for TS in the appropriate clinical context.

Pathway for the Management of Atrial Fibrillation and Atrial Flutter

Atrial fibrillation (AF) is the most common cardiac rhythm disturbance encountered in clinical practice, and its prevalence is increasing as the population ages. The American College of Cardiology, the American Heart Association, and the European Society of Cardiology established guidelines for the management of patients with AF. Atrial flutter (Afl) is less common and is often associated with or preceded by AF or occurs in an isolated pattern. A major limitation of the currently published guidelines for the management of patients with AF and Afl is their complexity, the fact that official guidelines are published separately for each of these arrhythmias, and that they were published several years ago. To address these deficiencies, we have developed a novel pathway for the management of AF and Afl. The pathway has been designated with the acronym RACE, which reflects the 4 main components in patient management: rate control, anticoagulation therapy, cardioversion, and electrophysiology/antiarrhythmic medication. This pathway is an attempt to incorporate, in a user-friendly format, the key concepts of the initial diagnosis and management of these prevalent arrhythmias. This is followed by a comprehensive guideline for therapy using the RACE acronym.

Structural Comparison between the Right and Left Atrial Appendages Using Multidetector Computed Tomography

The three-dimensional (3D) structures of the right atrial appendage (RAA) and left atrial appendage (LAA) were compared to clarify why thrombus formation less frequently occurs in RAA than in LAA. Morphological differences between RAA and LAA of 34 formalin-preserved cadaver hearts were investigated. Molds of RAA and LAA specimens were made and the neck areas, volumes of the atrial appendages (AA), and amount of pectinate muscles (PMs) were analyzed using multidetector computed tomography. In RAA, most PMs were connected to one another and formed a “dendritic” appearance and the inner surface area was smaller than in LAA. RAA had smaller volumes and larger neck areas than LAA. The ratios of the neck area/volume were larger and the amounts of PMs were smaller in RAA than in LAA. The volumes, neck areas, and amount of PMs of RAA were significantly correlated with those of LAA. According to the 3D structure, RAA appears to be suited for a more favorable blood flow, which may explain why the thrombus formation is less common in RAA than in LAA. Examining not only LAA but also RAA by transesophageal echocardiography may be useful in high-risk patients of thrombus formation in LAA because the volume, neck area, and amount of PMs of LAA reflect the shape of RAA.

Quantitative analysis of the right auricle with 256-slice computed tomography

PURPOSE

To quantitatively measure the morphology parameters of the right auricle with 256-slice multidetector computed tomography angiography (MDCTA) in healthy people.

MATERIALS AND METHODS

A retrospective analysis of 200 patients who had undergone coronary MDCTA with negative findings was performed. The raw imaging data were reconstructed and the right auricular volume, right atrial volume, right auricle height, base long and short axes, base perimeter and area, normal angle, and distance were quantitatively measured.

RESULTS

Men had significantly (P < 0.05) greater values than women in the right auricular volume (13.3 ± 4.0 vs. 11.7 ± 3.7 mL) and height (33.0 ± 5.0 vs. 30.5 ± 5.2 mm), the base long axis (34.4 ± 4.1 vs. 33.2 ± 3.9 mm), area (787.6 ± 177.6 vs. 771.0 ± 143.2 mm²) and perimeter (119.2 ± 17.5 vs. 115.0 ± 13.0), and the normal distance (22.4 ± 6.6 vs. 20.2 ± 6.7 mm). The normal 95 % reference range for the right auricular parameters was put forward. The right auricular parameters had a good correlation with the right atrium volume, aortic diameter, the body weight, height, and body surface area but a bad correlation with the vertebral body height. Significantly (P < 0.05) greater values were found in the normal angle and distance in subjects below than over 40 years of age. No other significant (P > 0.05) difference existed in the other right auricular parameters.

CONCLUSION

Quantitative measurements of the right auricle can help us get a good understanding of the right auricular morphology and its relationship with surrounding structures and are helpful for cardiac interventions of electrophysiology and radiofrequency ablation.

Assessment of left and right atrial 3D hemodynamics in patients with atrial fibrillation: a 4D flow MRI study

Atrial fibrillation (AF) is associated with embolic stroke due to thrombus formation in the left atrium (LA). Based on the relationship of atrial stasis to thromboembolism and the marked disparity in pulmonary versus systemic thromboembolism in AF, we tested the hypothesis that flow velocity distributions in the left (LA) versus right atrium (RA) in patients with would demonstrate increased stasis. Whole heart 4D flow MRI was performed in 62 AF patients (n = 33 in sinus rhythm during imaging, n = 29 with persistent AF) and 8 controls for the assessment of in vivo atrial 3D blood flow. 3D segmentation of the LA and RA geometry and normalized velocity histograms assessed atrial velocity distribution and stasis (% of atrial velocities <0.2 m/s). Atrial hemodynamics were similar for RA and LA and significantly correlated (mean velocity: r = 0.64; stasis: r = 0.55, p < 0.001). RA and LA mean and median velocities were lower in AF patients by 15-33 % and stasis was elevated by 11-19 % compared to controls. There was high inter-individual variability in LA/RA mean velocity ratio (range 0.5-1.8) and LA/RA stasis ratio (range 0.7-1.7). Patients with a history of AF and in sinus rhythm showed most pronounced differences in atrial flow (reduced mean velocities, higher stasis in the LA). While there is no systematic difference in LA versus RA flow velocity profiles, high variability was noted. Further delineation of patient specific factors and/or regional atrial effects on the LA and RA flow velocity profiles, as well as other factors such as differences in procoagulant factors, may explain the more prevalent systemic versus pulmonary thromboembolism in patients with AF.

Prevalence of left atrial thrombus in patients with non-valvular atrial fibrillation. A systematic review and meta-analysis of the literature

We performed a meta-analysis about the prevalence of left atrial thrombus (LAT) in patients with atrial fibrillation (AF) undergoing trans-esophageal echocardiography (TEE). Studies reporting on LAT presence in AF patients were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases and the pooled LAT prevalence was evaluated as weighted mean prevalence (WMP). Seventy-two studies (20,516 AF patients) showed a LAT WMP of 9.8 % (95 %CI: 7.6 %-12.5 %). LAT presence was associated with a higher age (mean difference: 2.56, 95 %CI: 1.49-3.62), and higher prevalence of female gender (OR: 1.35, 95 %CI: 1.04-1.75), hypertension (OR: 1.78, 95 %CI: 1.38-2.30), diabetes mellitus (OR: 1.86, 95 %CI: 1.33-2.59) and chronic heart failure (OR: 3.67, 95 %CI: 2.40-5.60). Overall, LAT patients exhibited a higher CHADS2-score (mean difference 0.88, 95 %CI: 0.68-1.07) and a higher risk of stroke/systemic embolism (OR: 3.53, 95 %CI: 2.24-5.56) compared with those without LAT. A meta-regression showed an inverse association between LAT prevalence and the presence of anticoagulation (Z-value: -7.3, p< 0.001). Indeed, studies in which 100 % of patients received oral anticoagulation reported a 3.4 % WMP of LAT (95 %CI: 1.3 %-8.7 %), whereas studies in which 0 % of patients received anticoagulation showed a LAT WMP of 7.4 % (95 %CI: 2.3 %-21.5 %). Our data suggest that LAT is present in ≍10 % of AF patients, and is associated with a 3.5-fold increased risk of stroke/systemic embolism. Interestingly, LAT is also reported in some of patients receiving anticoagulation. The implementation of the screening of LAT in AF patients before cardioversion/ablation could be useful for the prevention of vascular events.

The CHA2DS2-VASc score as a predictor of left atrial thrombus in patients with non-valvular atrial fibrillation

OBJECTIVE

To investigate whether or not the CHA2DS2-VASc score predicts left atrial (LA) thrombus detected on pre-cardioversion transoesophageal echocardiography (TEE).

MATERIALS AND METHODS

The medical records of patients who had undergone TEE were reviewed to assess the presence of LA thrombus prior to direct-current cardioversion for atrial fibrillation (AF). The CHA2DS2-VASc score was calculated for each patient. Clinical TEE reports were reviewed for the presence of LA thrombus. Patients with a valve prosthesis or rheumatic mitral valve disease were excluded from this study.

RESULTS

A total of 309 patients were identified. The mean age was 70.1 ± 9.8 years and 151 (49%) patients were males and 158 (51%) were females. LA thrombus was seen in 32 (10.3%) of the 309 patients. Fifty (16.2%) patients had a low CHA2DS2-VASc score (0-1), 230 (74.4%) had an intermediate score (2-4) and 29 (9.4%) had a high score (5-9). The incidence of LA thrombus in the low, intermediate and high CHA2DS2-VASc score groups was 0, 4.4 and 68.7%, respectively. The LA thrombus risk increased with increasing CHA2DS2-VASc scores. On multivariate logistic analysis, the CHA2DS2-VASc score (OR 3.26, 95% CI 2.3-4.65; p = 0.001) and age (OR 0.93, 95% CI 0.88-0.98; p = 0.004) were independent risk factors for LA thrombus in patients with non-valvular AF.

CONCLUSION

A high CHA2DS2-VASc score was independently associated with the presence of LA thrombus in patients with non-valvular AF.

Atrial fibrillation

Atrial fibrillation is the most common arrhythmia affecting patients today. Disease prevalence is increasing at an alarming rate worldwide, and is associated with often catastrophic and costly consequences, including heart failure, syncope, dementia, and stroke. Therapies including anticoagulants, anti-arrhythmic medications, devices, and non-pharmacologic procedures in the last 30 years have improved patients' functionality with the disease. Nonetheless, it remains imperative that further research into AF epidemiology, genetics, detection, and treatments continues to push forward rapidly as the worldwide population ages dramatically over the next 20 years.

Efficacy of the CHADS₂ scoring system to assess left atrial thrombogenic milieu risk before cardioversion of non-valvular atrial fibrillation

The CHADS₂ scoring system was found to be a good predictor for risk stratification of stroke in patients with atrial fibrillation. The effectiveness of this scoring system in assessing thrombogenic milieu before direct-current cardioversion has not yet fully been established on a large scale. In this study, data from 2,369 consecutive patients in whom transesophageal echocardiography was performed for screening before direct-current cardioversion from 1999 to 2008 were analyzed. Left atrial (LA) or LA appendage (LAA) thrombogenic milieu (spontaneous echo contrast, sludge, and thrombus) was investigated. The results were correlated with CHADS₂ score findings. The mean age was 66 ± 13 years, and the ratio of men to women was 2.2:1. CHADS₂ scores of 0, 1, 2, 3, 4, 5 and 6 were present in 11%, 25%, 30%, 22%, 8%, 3%, and 1% of the studies, respectively. The prevalence of LA or LAA sludge or thrombus increased with increasing CHADS₂ scores (2.3%, 7%, 8.5%, 9.9%, 12.3%, and 14.1% for scores of 0, 1, 2, 3, 4, and 5 or 6, respectively, p = 0.01). In a multivariate model, an ejection fraction ≤20% was the best predictor of LA or LAA sludge or thrombus (odds ratio 2.99, p <0.001). In conclusion, transesophageal echocardiographic markers of thrombogenic milieu were highly correlated with increasing CHADS₂ scores in patients who underwent transesophageal echocardiography-guided cardioversion. Giving more value to echocardiographic findings, such as the left ventricular ejection fraction, and its different levels (especially an ejection fraction ≤20%) might improve the precision of the CHADS₂ scoring scheme to predict thrombogenic milieu in the left atrium or LAA as a surrogate to cardioembolic risk in patients with atrial fibrillation.

Management of late arrhythmias in adults with repaired congenital heart disease

OPINION STATEMENT

As survival of patients with congenital heart disease improves with surgery and the population of patients with repaired adult congenital heart disease (ACHD) age, understanding complications such as arrhythmias has become more important. Arrhythmias account for significant morbidity and mortality in the ACHD population. Atrial arrhythmias occur in 15 % of patients with ACHD and, in patients with severe congenital heart disease (CHD), more than 50 % develop atrial arrhythmias by the age of 65 years [1]. This article aims to give an overview of arrhythmias seen in the ACHD population and the treatment modalities available now.

Role of CHADS2 score in evaluation of thromboembolic risk and mortality in patients with atrial fibrillation undergoing direct current cardioversion (from the ACUTE Trial Substudy)

The CHADS(2) (congestive heart failure, hypertension, age >75 years, diabetes mellitus, stroke or transient ischemic attack [2 points]) scoring scheme has been found to be a good predictor of stroke risk in patients with nonvalvular atrial fibrillation (AF). However, the value of the CHADS(2) scoring system in the risk stratification of patients with AF who undergo direct-current cardioversion has not yet been specifically investigated. In this study, a subgroup of 541 patients from the Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) study who had AF for >48 hours and planned to undergo transesophageal echocardiography before direct-current cardioversion were enrolled. Each patient had a CHADS(2) score calculated. Of the patients with CHADS(2) scores of 0, 14 (10%) were found to have left atrial appendage thrombi on transesophageal echocardiography. After 6 months of follow up, patients with CHADS(2) scores of 3 to 6 showed a significantly higher mortality rate in comparison with patients with lower CHADS(2) scores (4.3% vs 0.5%, p = 0.004), despite their similar prevalence of left atrial appendage thrombus and stroke (thrombus: 13.4% vs 11.6%, p = 0.60; stroke: 0% vs 0.3%, p = 0.70). In conclusion, the CHADS(2) scoring system may be useful for predicting short-term mortality risk in patients with AF receiving elective direct-current cardioversion. However, in the preprocedural risk assessment of these patients, the CHADS(2) scoring system is not reliable in predicting risk for left atrial appendage thrombus formation, especially in patients with low CHADS(2) scores.

Usefulness of transesophageal echocardiography to confirm clinical utility of CHA2DS2-VASc and CHADS2 scores in atrial flutter

The CHA(2)DS(2)-VASc and CHADS(2) risk stratification schemes are used to predict thromboembolism and ischemic stroke in patients with atrial fibrillation. However, limited data are available regarding the utility of these risk stratification schemes for stroke in patients with atrial flutter. A retrospective analysis of 455 transesophageal echocardiographic studies in patients with atrial flutter was performed to identify left atrial (LA) thrombi and/or spontaneous echocardiographic contrast (SEC). The CHA(2)DS(2)-VASc (Congestive heart failure, Hypertension, Age ≥75 years [doubled risk weight], Diabetes mellitus, previous Stroke/transient ischemic attack [doubled risk weight], Vascular disease, Age 65 to 74 years, Sex) and CHADS(2) (Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, previous Stroke/transient ischemic attack [double risk weight]) scores were calculated to stratify the risk of stroke or transient cerebrovascular ischemic events. Transesophageal echocardiography revealed LA thrombi in 5.3% and SEC in 25.9% of patients. Using CHADS(2), LA thrombus was found in 2.2% of the low-intermediate-risk group and 8.3% of the high-risk group (p = 0.005). SEC was found in 19.8% of the low-intermediate-risk group and 32% of the high-risk group (p = 0.004). Using CHA(2)DS(2)-VASc, LA thrombus was found in 1.7% of the low-intermediate-risk group and 6.5% of the high-risk group (p = 0.053). SEC was found in 11.8% of the low-intermediate-risk group versus 30.9% of the high-risk group (p = 0.004). The sensitivity for LA thrombus/SEC with a high CHADS(2) and CHA(2)DS(2)-VASc score was 64.8% and 88.7%, respectively (p = 0.0001). The specificity for LA thrombus/SEC with high CHADS(2) and CHA(2)DS(2)-VASc scores was 52.6% and 28.9%, respectively (p = 0.0001). In conclusion, both CHA(2)DS(2)-VASc and CHADS(2) scores are useful for stroke risk stratification in patients with atrial flutter. CHA(2)DS(2)-VASc had greater sensitivity for LA thrombus and SEC detection at the cost of reduced specificity.

Esophageal electrical cardioversion of atrial fibrillation: when esophagus gives a help to cardiologists

Atrial fibrillation is a common clinical disease especially in the elderly and in patients with organic heart disease. Electrical cardioversion is the first choice therapeutic approach for patients in which sinus rhythm could improve the quality of life and where the maintenance of sinus rhythm is considered likely. There are different techniques to perform an electrical cardioversion, each with specific indications, advantages, and limitations. The method most frequently used to restore sinus rhythm is external direct current cardioversion; however, this technique has some disadvantages, since it requires a high energy and usually general anesthesia. Esophageal cardioversion is an alternative method to obtain restoration of sinus rhythm, warranting acute and long-term results absolutely comparable with those obtained by the conventional transthoracic technique, especially in obese and COPD patients with high thoracic impedance for whom the standard technique may be less effective.

Thromboembolism in patients with atrial fibrillation with and without left atrial thrombus documented by transesophageal echocardiography

The incidence of cerebrovascular events (CVEs) was investigated in 95 consecutive patients with atrial fibrillation (AF) with left atrial thrombus (LAT) diagnosed by transesophageal echocardiography (TEE) and in 131 age- and sex-matched AF patients without LAT. Compared with patients without LAT, patients with LAT had a larger left atrial diameter (49 versus 44 mm, P < 0.0001), a lower left ventricular ejection fraction (40% versus 50%, P < 0.0001), a higher prevalence of spontaneous echocardiographic contrast (88% versus 25%, P < 0.001), a reduced left atrial appendage emptying velocity (0.25 versus 0.41 cm/s, P < 0.0001), and less use of antiarrhythmic drugs (61% versus 76%, P = 0.03). Before TEE, the prevalence of prior CVE was higher in LAT patients (20%) compared with patients without LAT (8%) (P = 0.01). Fifty-four of 95 LAT patients (57%) and 81 of 131 non-LAT patients (62%) were on warfarin before TEE. The incidence of prior CVE in LAT patients without warfarin (32%) was higher than that in non-LAT patients without warfarin (10%) (P = 0.02). The mortality rate in LAT patients with an international normalized ratio (INR) >or= 2.0 (42%) was higher than that in patients without LAT and an INR >or= 2.0 (11%) (P < 0.001). Fifty-one of 95 LAT patients (54%) underwent repeat TEE before cardioversion (48 patients received warfarin therapy). The thrombus resolved in 40 of 51 patients (78%) after the first TEE. There was no significant difference in INR between the patients with persistent and resolved LAT. AF patients with persistent LAT had a higher incidence of CVE (45%) than the patients with resolved LAT (5%) (P = 0.003). We suggest that patients with LAT be treated with warfarin to maintain an INR between 2.5 and 3.5 rather than between 2.0 and 3.0 because they are at a high risk for new thromboembolism.

Role of the CHADS2 score in the evaluation of thromboembolic risk in patients with atrial fibrillation undergoing transesophageal echocardiography before pulmonary vein isolation

OBJECTIVES

The goals of this study were to determine: 1) if low-risk patients assessed by a CHADS(2) score, a clinical scoring system quantifying a risk of stroke in patients with atrial fibrillation (AF), require a routine screening transesophageal echocardiogram (TEE) before pulmonary vein isolation (PVI); and 2) the relationship of a CHADS(2) score with left atrial (LA)/left atrial appendage (LAA) spontaneous echo contrast, sludge, and thrombus.

BACKGROUND

There is no clear consensus of whether a screening TEE before catheter ablation of AF should be performed in every patient.

METHODS

Initial TEEs for pre-PVI of 1,058 AF patients (age 57 +/- 11 years, 80% men) were reviewed and compared with a CHADS(2) score.

RESULTS

CHADS(2) scores of 0, 1, 2, 3, 4, 5, and 6 were present in 47%, 33%, 14%, 5%, 1%, 0.3%, and 0% of patients, respectively. The prevalence of LA/LAA thrombus, sludge, and spontaneous echo contrast were present in 0.6%, 1.5%, and 35%. The prevalence of LA/LAA thrombus/sludge increased with ascending CHADS(2) score (scores 0 [0%], 1 [2%], 2 [5%], 3 [9%], and 4 to 6 [11%], p < 0.01). No patient with a CHADS(2) score of 0 had LA/LAA sludge/thrombus. In a multivariate model, history of congestive heart failure and left ventricular ejection fraction <35% were significantly associated with sludge/thrombus.

CONCLUSIONS

The prevalence of LA/LAA sludge/thrombus in patients with AF undergoing a pre-PVI screening TEE is very low (<2%) and increases significantly with higher CHADS(2) scores. This suggests that a screening TEE before PVI should be performed in patients with a CHADS(2) score of >or=1, and in patients with a CHADS(2) score of 0 when the AF is persistent and therapeutic anticoagulation has not been maintained for 4 weeks before the procedure.

Role of transesophageal echocardiography among patients with atrial fibrillation undergoing electrophysiology testing

External or internal shocks administered to terminate ventricular arrhythmias as a part of electrophysiology or implantable cardioverter-defibrillator testing, can inadvertently cardiovert atrial fibrillation (AF). Moreover, anticoagulation therapy is often withheld in these patients in anticipation of an invasive procedure. The risk of embolic events during these procedures has not been well described. Accordingly, the present study was a prospective evaluation of the incidence of left atrial (LA) thrombus and AF cardioversion among patients undergoing ventricular arrhythmia assessment. Transesophageal echocardiography was routinely performed on 44 consecutive patients in AF with subtherapeutic anticoagulation undergoing electrophysiology or implantable cardioverter-defibrillator testing. Arrhythmia induction was not performed when LA thrombus was present. The incidence and clinical predictors of thrombus, the inadvertent cardioversion of AF, and adverse events related to the procedure were assessed during the subsequent 4 to 6 weeks. Left atrial thrombus was observed in 12 patients (27%). Sinus rhythm was restored in 29 patients (91%), at least transiently, who underwent testing with a shock delivered. No adverse neurologic or hemorrhagic complications were observed. Univariate analysis identified no predictors of LA thrombus or cardioversion to sinus rhythm. In conclusion, LA thrombus and cardioversion to sinus rhythm are common among patients with AF undergoing an evaluation of ventricular arrhythmias. Transesophageal echocardiography performed before the procedure in patients with subtherapeutic anticoagulation is warranted to minimize embolic complications. This strategy appears to be a safe method to guide diagnostic testing in this patient population.

Presence Of Left Atrial Appendage Thrombus In Patients Presenting For Left Atrial Ablation Of Atrial Fibrillation Despite Pre-Operative Anticoagulation

Background: One of the recognised complications of left atrial ablation for atrial fibrillation (AF) is stroke. Left atrial (LA) thrombus, which may be dislodged by catheter manipulation, is an absolute contraindication to ablation. It is unclear whether imaging of the left atrial appendage (LAA) by transesophageal echo (TEE) is mandatory to exclude LA clot prior to ablation, particularly in "low-risk" patients with paroxysmal AF and normal left ventricular (LV) function. Methods and Results: We carried out a retrospective analysis of pre-ablation TEE in patients presenting for ablation of AF. Images from 244 ablation procedures carried out in 148 patients were examined, including 106 patients with paroxysmal AF and normal LV function. Despite at least 4 weeks of pre-operative therapeutic anticoagulation with Warfarin (INR>2.0), LAA thrombus was identified in 4 patients (2.7% (0.1-5.3%)). These included 2 patients with paroxysmal AF and normal LV function, although both had a high arrhythmia burden. The thrombi regressed with intensification of anticoagulation. Conclusions: Pre-operative imaging of the LAA remains advisable to exclude thrombus prior to ablation for AF even in patients with paroxysmal AF and normal LV function, especially if there is a high AF burden.

Right Atrial Appendage: Forgotten Part of the Heart in Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinically encountered arrhythmia in adults. Because it is associated with an increased risk of atrial thrombus formation and embolism, medical and/or electrical cardioversion is the preferred treatment method in the majority of clinics. Thrombus formation in the setting of AF most commonly occurs in the left atrial appendage (LAA), left atrium (LA), right atrial appendage (RAA), and right atrium in decreasing frequency. In routine transesophageal echocardiographic evaluation for AF, examination is generally limited to LA and LAA. Although relatively rare when compared with the left side, RAA thrombus has also the potential of embolism and should be screened. A case of RAA thrombus in which the LA and LAA were spared is described. The authors aimed to underline the importance of this rare but potentially dangerous complication of AF.

Is early cardioversion for atrial fibrillation safe in patients with spontaneous echocardiographic contrast?

The 2006 American Heart Association guidelines for management of patients with atrial fibrillation state "For patients with no identifiable thrombus in the left atrium (LA) or left atrial appendage (LAA), cardioversion (CV) is reasonable immediately after anticoagulation with unfractionated heparin. Thereafter, continuation of oral anticoagulation is reasonable for an anticoagulation period of at least 4 weeks". For patients with thrombus identified by transesophageal echocardiography, guidelines recommend therapeutic oral anticoagulation for 3 weeks prior to and 4 weeks after elective cardioversion. Patients with spontaneous echo contrast (SEC) identified by TEE have a high risk of thromboembolic events,1-8 however, the guidelines do not address whether patients with SEC without thrombus can be safely cardioverted. This paper reviews the literature describing the pathogenesis of SEC, how it is detected, and whether elective cardioversion is safe. On the basis of our review, we believe that the risk of cardioembolic stroke after cardioversion of a patient with SEC is low, regardless of anticoagulation. The safe conclusion is that patients with SEC on TEE should receive therapeutic anticoagulation prior to cardioversion if possible and early cardioversion is not contraindicated.

Clinical and Echocardiographic Risk Factors for Embolization in the Presence of Left Atrial Thrombus

AIMS

The aim of our study was to evaluate the factors leading to embolization in patients with left atrial thrombi (LAT). With this purpose, we retrospectively analyzed clinical, transthoracic, transesophageal echocardiographic data of patients with LAT in the transesophageal echocardiographic evaluation.

METHODS AND RESULTS

One hundred ninety-two patients with LAT not on anticoagulant therapy were divided into two groups according to the presence of prior ischemic stroke. The group with ischemic stroke included more patients with sinus rhythm and less patients with mitral stenosis. They had smaller left atrial diameter, more left atrial appendage spontaneous echo-contrast, higher appendage ejection fraction, and emptying velocity.

CONCLUSION

Once the thrombus has been formed, cerebral embolization seems to be higher in patients with relatively preserved appendage ejection fraction and emptying velocity. Presence of atrial appendage spontaneous echo-contrast also favor embolization. Factors leading to embolization seem to differ in some respects from the causes of thrombus formation.

Long-term sinus rhythm maintenance after cardioversion of persistent atrial fibrillation: is the treatment's success predictable?

The aim of our study was to identify the clinical and echocardiographic predictors of long-term success of cardioversion in patients with persistent atrial fibrillation (AF). Our study comprised 104 patients (F/M 33/71; mean age 60.4 +/- 7.9 years) assigned to SR restoration and maintenance with sequentially administered antiarrhythmic drugs. Their clinical and transthoracic echocardiographic (TTE) variables were recorded prior to cardioversion and examined for correlation with sinus rhythm (SR) maintenance at 1 year. The variables under consideration included age, gender, echo parameters such as long and short left atrial (LA) axis, LA and right atrial (RA) area, fractional shortening (FS) and left ventricular end-diastolic diameter, AF duration, New York Heart Association functional class, and concomitant diseases. Generalized additive logistic regression method was used to investigate impact of the selected variables on long-term SR maintenance. At 1 year, SR was present in 63.5% of patients. Left atrium area (LA(ar)) > 28 cm (P < 0.02) and FS value >26% (P < 0.05), both measured at baseline, were significantly associated with SR maintenance after 1 year. Patients with large LA(ar) values (>28 cm(2)) presented a significant decrease (31.45 +/- 3.07 cm(2) vs 28.94 +/- 3.81 cm(2); P < 0.008) during 30 days following SR maintenance. In patients with LA(ar) >28 cm(2) we noted an atrial decrease of 2.57 +/- 3.2 cm(2) (P < 0.004) during 30 days following SR restoration, which turned out to be an independent factor related to SR presence at 1 year of follow-up (relative risk 1.83; 95% confidence interval: 1.03-2.95; P < 0.01). Of all the considered variables only LA area and FS value seem to be relatively reliable predictors of SR sustainability at 1 year after an effective cardioversion of persistent AF.

Cardiovascular Imaging in the Management of Atrial Fibrillation

Atrial fibrillation (AF) is he most commonly encountered arrhythmia in clinical practice, with an overall prevalence of 0.4% in the general population. Recent advances in technology and in the understanding of the pathophysiology of AF have led to more definitive and potentially curative therapeutic approaches. Echocardiography has a well-established role in the assessment of cardiac structure and function and risk stratification, and has become an essential part of the guidelines for management of AF. The development of intracardiac echocardiography has led to real-time guidance of percutaneous interventions, including radiofrequency ablation and left atrial appendage closure procedures for patients with AF. Other imaging modalities, including computed tomography and magnetic resonance angiography, have allowed for more accurate measurement and better understanding of the cardiac anatomy. We review the impact of various imaging modalities in the evaluation and management of AF.

[TEE-guided cardioversion in patients with atrial fibrillation without previous anticoagulation]

A total of 332 patients (mean age 65+/-10 years, 86 female) with nonvalvular atrial fibrillation (AF) of more than 48 hours duration and lack of a sufficient anticoagulation were included. After exclusion of thrombotic material in the left atrium using transesophageal echocardiography (TEE) cardioversion (CV) was performed within 24 hours. At the same time oral anticoagulation (AC) (overlapping with PTT-affecting heparinisation) was started. If thrombi were found by TEE, the examination was repeated after at least four weeks of anticoagulation. If thrombi were absent at this time, CV was performed. Periprocedural embolism was defined as primary endpoint, whereas the detection of atrial thrombi before CV was defined as secondary endpoint. In 33 of the 332 Patients (9.9%) the TEE showed a thrombus in the left atrium respectively the left atrial appendage (n=22) or thrombi could not be excluded (n=11). 383 TEEs were performed without complications in an overall of 332 patients.A total of 305 CV were performed (electrical n=300, pharmacological n=5) and during periprocedural monitoring and in the time of four weeks after CV no thromboembolic complications were observed.TEE-guided CV in patients with AF persisting for more than 48 hours and without previous AC can be considered as a method that is both safe and effective.

Electrical cardioversion of atrial fibrillation: different methods for a safe and effective technique

Atrial fibrillation is the most common cardiac arrhythmia observed in clinical practice. Many different therapeutic approaches are available at present but none may be considered the gold standard treatment. Antiarrhythmic drugs are not very effective agents to cardiovert persistent atrial fibrillation and, therefore, the technique most frequently used to restore sinus rhythm is external direct current cardioversion, which has proved to be safe and very effective. Esophageal cardioversion is an alternative method that could obviate some of the limitations of the external technique, such as the high energy required, need for anesthesia and longer hospital stay. Another technique performed during the last two decades is internal cardioversion, but at present, the advantage of this technique is limited to the small proportion of cases of unsuccessful external cardioversion.