Role of echocardiography in patients undergoing elective cardioversion of atrial fibrillation

Stuck between a rock and a hard place: heart failure with bilateral atrial appendage thrombi and disseminated intravascular coagulation-a case report

Background

The simultaneous occurrence of left atrial appendage (LAA) and right atrial appendage (RAA) thrombosis is a rare finding in atrial fibrillation (AF). In addition, concomitant conditions, such as heart failure (HF) and disseminated intravascular coagulation (DIC), could be associated with intracardiac thrombosis. Morganella morganii is an emerging pathogen, and the association with DIC and cardiac thrombosis is not yet described.

Case summary

A 69-year-old Caucasian man was admitted to the hospital for progressive dyspnoea and new-onset diarrhoea. His physical examination revealed signs of HF and new-onset AF; laboratory tests showed marked thrombocytopaenia and coagulopathy. Blood and urine cultures were positive for M. morganii, and the International Society on Thrombosis and Hemostasis criteria were diagnostic for DIC. Transthoracic echocardiogram revealed a large, mobile left atrial mass and severely reduced left ventricular function. Transoesophageal echocardiogram showed two masses: one in the LAA and one in the RAA. Positron emission tomography/computed tomography scan excluded infective endocarditis and malignancies. After the beginning of antibiotic therapy and anticoagulation, the patient developed severe bleeding. Unfortunately, his haemodynamic status was complicated by multi-organ failure, and at the end, he developed irreversible cardiogenic shock. We present this challenging case of HF and AF complicated by DIC in the context of M. morganii infection.

Discussion

Multiple mechanisms, such as inflammatory storm, activation of coagulation cascade, and amplified immune response, may explain the hyper-coagulable state related to DIC. In our case, HF, AF, and DIC may have facilitated RAA thrombosis, which is a rare finding. To the best of our knowledge, this is the first reported case of concomitant cardiac thrombosis as a complication of DIC in the context of M. morganii infection. This highlights the need among clinicians for an increased awareness about this pathogen and the complications of its infection.

Supraventricular Tachycardia (SVT) and Stroke: Should We Pump the Brakes on Cardioversion?

In the list of top 10 causes of death worldwide in 2019, stroke ranks number two, with a recent uptick in incidence involving younger adults. While common risk factors like tobacco use, hypertension, diabetes, and atrial fibrillation have been well studied, recent reports have also linked paroxysmal supraventricular tachycardia (PSVT) with strokes. This case highlights a rare presentation of a 25-year-old female who suffered an ischemic stroke shortly after undergoing chemical cardioversion for sustained SVT. To date, there are only three documented cases reporting an ischemic event following shortly after cardioversion of SVT, all confined to the pediatric population. Currently, there is limited evidence to guide the management of these complex patients. This case presents a valuable discussion regarding the futility or efficacy of imaging prior to cardioversion of SVT as well as furthers the conversation behind the theorized mechanisms linking PSVT and strokes.

Computed Tomography to Exclude Cardiac Thrombus in Atrial Fibrillation-An 11-Year Experience from an Academic Emergency Department

BACKGROUND

Computed tomography (CT) could be a suitable method for acute exclusion of left atrial appendage thrombus (LAAT) prior to cardioversion of atrial fibrillation (AF) and atrial flutter (AFL) at the emergency department. Our aim was to present our experiences with this modality in recent years.

METHODS

This registry-based observational study was performed at the Department of Emergency Medicine at the Medical University of Vienna, Austria. We studied all consecutive patients with AF and AFL who underwent CT between January 2012 and January 2023 to rule out LAAT before cardioversion to sinus rhythm was attempted. Follow-ups were conducted by telephone and electronic medical records. The main variables of interest were the rate of LAAT and ischemic stroke at follow-up.

RESULTS

A total of 234 patients (143 [61%] men; median age 68 years [IQR 57-76], median CHA2DS2-VASc 2 [IQR 1-4]) were analyzed. Follow-up was completed in 216 (92%) patients after a median of 506 (IQR 159-1391) days. LAAT was detected in eight patients (3%). A total of 163 patients (72%) in whom LAAT was excluded by CT were eventually successfully cardioverted to sinus rhythm. No adverse events occurred during their ED stay. All patients received anticoagulation according to the CHA2DS2-VASc risk stratification, and no patient had suffered an ischemic stroke at follow-up, resulting in an incidence risk of ischemic strokes of 0% (95% CI 0.0-1.2%).

CONCLUSION

LAAT was rare in patients admitted to the ED with AF and AFL who underwent cardiac CT prior to attempted cardioversion. At follow-up, no patient had suffered an ischemic stroke. Prospective studies need to show whether this strategy is suitable for the acute treatment of symptomatic AF in the emergency setting.

The Predictive Value of the Left Atrial Kinetic Energy for Atrial Fibrillation Recurrence

Background and aim

Determining which patients will experience recurrence of atrial fibrillation (AF) is crucial for treatment modification. This study aimed to investigate the predictive value of left atrial kinetic energy (LAKE) in AF recurrence.

Materials and methods

A total of 120 consecutive patients who achieved sinus rhythm (SR) with electrical direct current cardioversion and met the inclusion criteria were included in the study. Transthoracic echocardiography (TTE) and LAKE values were calculated on the first day after cardioversion. Rhythm control was performed with 12-lead electrocardiography in the first-month follow-up.

Results

While 81 (67.5%) patients were in SR at one month, AF recurrence was detected in 39 (32.5%) patients. In the AF group, AF duration, cardioversion energy, number of diabetic patients, left atrium (LA) diameter, LA pre-mitral A wave volume, LA minimum volume, and pulmonary artery pressure values were significantly higher than in the SR group, while mitral A wave velocity and LAKE values were significantly lower. In multivariate regression analysis, AF duration (OR: 1.54; 95% CI: 1.22 - 1.93; p < 0.001), LA diameter (OR: 1.33; 95% CI: 1.10 - 1.61; p = 0.002), and LAKE (OR: 0.96; 95% CI: 0.94 - 0.99; p = 0.007) were determined to be independent predictors of AF recurrence at one month.

Conclusions

LA diameter, AF duration, and LAKE were found to be significant predictors of AF recurrence after cardioversion.

Association of COVID-19 infection with large thrombi in left and right atrial appendages

Background

Multiple intra-atrial thrombi are found rarely except in the presence of prosthetic valves, intra-cardiac devices, structural connections like foramen ovale and thrombophilia.

Case presentation

We reported acute thrombosis formation in right and left atrial appendages of a 66-year old man admitted due to progressive dyspnea since 7 days earlier. He had a history of prior laryngeal Squamous Cell Carcinoma, apical hypertrophic cardiomyopathy (HCM), and atrial fibrillation (AF). Infection with COVID-19 was confirmed thereafter. Cardiac Magnetic Resonance Imaging (CMR) suggested the diagnosis of atrial clot superior to neoplasm. After surgical removal of the thrombi, symptoms as well as imaging features of pneumonia were resolved.

Conclusions

We should focus on different presentations and complications of systemic inflammation especially in the setting of COVID-19 infection. Although risk factors of thrombosis are present in some of these patients, rapid progression as well as unusual types of involvement may indicate to a new trigger.

Anticoagulation in Atrial Fibrillation Cardioversion: What Is Crucial to Take into Account

The therapeutic dilemma between rhythm and rate control in the management of atrial fibrillation (AF) is still unresolved and electrical or pharmacological cardioversion (CV) frequently represents a useful strategy. The most recent guidelines recommend anticoagulation according to individual thromboembolic risk. Vitamin K antagonists (VKAs) have been routinely used to prevent thromboembolic events. Non-vitamin K antagonist oral anticoagulants (NOACs) represent a significant advance due to their more predictable therapeutic effect and more favorable hemorrhagic risk profile. In hemodynamically unstable patients, an emergency electrical cardioversion (ECV) must be performed. In this situation, intravenous heparin or low molecular weight heparin (LMWH) should be administered before CV. In patients with AF occurring within less than 48 h, synchronized direct ECV should be the elective procedure, as it restores sinus rhythm quicker and more successfully than pharmacological cardioversion (PCV) and is associated with shorter length of hospitalization. Patients with acute onset AF were traditionally considered at lower risk of thromboembolic events due to the shorter time for atrial thrombus formation. In patients with hemodynamic stability and AF for more than 48 h, an ECV should be planned after at least 3 weeks of anticoagulation therapy. Alternatively, transesophageal echocardiography (TEE) to rule out left atrial appendage thrombus (LAAT) should be performed, followed by ECV and anticoagulation for at least 4 weeks. Theoretically, the standardized use of TEE before CV allows a better stratification of thromboembolic risk, although data available to date are not univocal.

Cardiovascular MRI: A valuable tool to detect cardiac source of emboli in cryptogenic ischemic strokes

OBJECTIVES

Despite a thorough work-up including transesophageal echocardiography, 20%-30% of stroke etiology remains cryptogenic. Transesophageal echocardiogram is considered the gold standard procedure to detect cardiac or aortic sources of emboli. In the recent years, cardiovascular MRI has emerged as a noninvasive, sound, and reliable modality to image morphological and functional abnormalities. In this study, we compared none contrast cardiovascular MRI to transesophageal echocardiogram, in the ability to detect cardiovascular source of embolus in cryptogenic ischemic strokes.

METHODS

A series of 24 patients who were labeled, after a thorough stroke work-up, as having cryptogenic stroke, were examined with both transesophageal echocardiogram and noncontrast cardiovascular MRI to assess for cardiac or aortic source of emboli. The cardiologist who interpreted the transesophageal echocardiograms was blinded to the results of cardiovascular MRI. At the same time, the radiologist who interpreted the cardiovascular MRI was also blinded to the results of transesophageal echocardiogram. The cardiac lesions, with potential source of emboli that were assessed in our study included left ventricular thrombus, atrial septal aneurysm, and aortic atherosclerotic disease. The ability of cardiovascular MRI to identify potential source of cardiac embolus was then compared to that of transesophageal echocardiogram.

RESULTS

Transesophageal echocardiogram detected ascending or arch aortic atherosclerotic plaque in 14 of the 24 patients. Other abnormalities detected include two atrial septal aneurysms and two left ventricular thrombus. Cardiovascular MRI was able to identify aortic atheroma in 13 patients; as well as three atrial septal aneurysms and two left ventricular thrombus. The accuracy of cardiovascular MRI to detect aortic atheroma, atrial septal aneurysm or left ventricular thrombus was great; 96%, 95.83%, and 100%, respectively.

CONCLUSION

This small study suggests that, in patients with cryptogenic stroke, cardiovascular MRI is comparable to transesophageal echocardiogram in detecting cardiac and aortic source of emboli.

Practical Implementation of Anticoagulation Strategy for Patients Undergoing Cardioversion of Atrial Fibrillation

Anticoagulation is routinely prescribed to patients with persistent AF before cardioversion to reduce the risk of thromboembolic events. As direct oral anticoagulants (DOACs) have a rapid onset of action, a consistent anticoagulant effect, if taken correctly, and do not need monitoring or dose adjustments, there is considerable interest in their use for patients with AF undergoing cardioversion. Post-hoc analyses show that DOACs are safe to use prior to and following cardioversion. In addition, two randomised controlled trials, X-VeRT and ENSURE-AF, have demonstrated the efficacy and safety of the DOACs rivaroxaban and edoxaban, respectively, in this setting. The use of DOACs allows cardioversions to be performed promptly and reduces the number of cancelled procedures compared with the use of warfarin.

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.

SAfety of Fondaparinux in transoesophageal echocardiography-guided Electric cardioversion of Atrial Fibrillation (SAFE-AF) study: a pilot study

BACKGROUND

Current guidelines recommend unfractionated heparin (UFH) or low-molecular-weight heparin plus an oral anticoagulant for the prevention of thromboembolism in patients undergoing electric cardioversion of atrial fibrillation (AF). Selective factor Xa inhibitors, such as fondaparinux, which has a favourable benefit-risk profile in the prevention and treatment of venous thromboembolism and the management of acute coronary syndromes, have not been systematically evaluated in this setting.

AIM

To evaluate the efficacy and safety of fondaparinux versus standard treatment in patients undergoing echocardiographically-guided cardioversion of AF.

METHODS

In this multicentre, randomized, open-label, controlled, two-parallel-group, phase II pilot study, patients with AF undergoing electric cardioversion following transoesophageal echocardiography (TEE) were randomized to fondaparinux or standard therapy (UFH plus vitamin K antagonist [VKA]). Patients showing an atrial thrombus in the first TEE (clot-positive) were randomized to treatment with fondaparinux or standard care for 4 weeks before cardioversion.

RESULTS

The primary endpoint (combined rate of cerebral neurological events, systemic thromboembolism, all-cause death and major bleeding events) occurred in 3 of 174 (1.7%) patients on fondaparinux and 2 of 170 (1.2%) patients on UFH+VKA. The rate of thrombus disappearance among clot-positive patients was higher in the fondaparinux arm (11 of 14; 78.6%) than in the UFH+VKA arm (7 of 14; 50.0%). Incidences of adverse events were similar (45.4% with fondaparinux and 46.5% with UFH+VKA).

CONCLUSION

In this pilot study in patients with TEE-guided cardioversion, the use of fondaparinux appeared to be well tolerated, with similar efficacy to UFH+VKA. Furthermore, a trend to greater thrombus resolution was observed.

Atrial fibrillation: an epidemic in the elderly

Atrial fibrillation is the most common cardiac arrhythmia that increases in prevalence with age. As the general population grows older, general practitioners will more frequently see this disease in their clinic population. In order to most effectively treat these patients, physicians need to understand key issues, including the use of rhythm control versus ventricular rate control and how to reduce the risk of ischemic stroke. This article will review recent advancements in the understanding of the pathophysiology, management, stroke risk stratification and prevention of thromboembolic complications in atrial fibrillation.

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.

Evaluating Cardiac Sources of Embolic Stroke with MRI

The evaluation of patients with stroke includes identifying its etiology in order to appropriately tailor therapy. Currently, the diagnostic work-up includes imaging of the brain, the arteries of the head and neck, the aorta, and the heart. Traditional methods of imaging include magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), duplex ultrasound, and transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE). While echocardiography remains a cornerstone in the field of cardiac imaging, MRI is increasingly able to assess for the most common causes of cardioembolic stroke such as left atrial/left atrial appendage thrombus, left ventricular thrombus, aortic atheroma, cardiac masses and patent foramen ovale. This review will focus on the advantages and limitations of echocardiography and cardiac magnetic resonance (CMR) imaging in diagnosing patients suspected of having an embolic stroke and the role these modalities play in clinical practice today.

Safety of expedited anticoagulation in patients undergoing transesophageal echocardiographic-guided cardioversion

BACKGROUND

In patients undergoing transesophageal echocardiography-guided cardioversion, we evaluated the use and safety of an expedited in-hospital anticoagulation regimen that incorporates shorter-than-standard durations of precardioversion intravenous unfractionated heparin and postcardioversion bridging therapy with a low-molecular-weight heparin.

METHODS

Adult patients who underwent successful transesophageal echocardiography-guided cardioversion for atrial fibrillation or atrial flutter between May 2000 and August 2003 were classified into 2 groups by duration of intravenous unfractionated heparin therapy (<24 h or > or =24 h) before transesophageal echocardiography and cardioversion. Safety end points evaluated included all-cause death, stroke or other thromboembolic events, and major bleeding complications within 1 month after successful cardioversion.

RESULTS

The study population of 386 patients included 199 (52%) who received expedited intravenous unfractionated heparin (<24 h; minimum duration, <4 h) and 193 patients (50%) who were discharged on low-molecular-weight heparin therapy. The adverse event rates at 1-month follow-up were not significantly different between the 2 unfractionated heparin patient groups, and the rate of stroke among patients dismissed on low-molecular-weight heparin was less than 1%. No adverse events occurred among patients who received intravenous unfractionated heparin for less than 12 hours and who were dismissed on low-molecular-weight heparin bridging therapy.

CONCLUSIONS

The use of an expedited heparin anticoagulation regimen in patients with atrial fibrillation or atrial flutter undergoing transesophageal echocardiography-guided cardioversion appears to be safe. Cardioversion can be performed as early as a few hours after initiation of intravenous unfractionated heparin, and bridging therapy with a low-molecular-weight heparin can be used after cardioversion until the international normalized ratio is therapeutic.

Efficacy of transesophageal echocardiography-guided cardioversion of patients with atrial fibrillation at 6 months: a randomized controlled trial

BACKGROUND

Electrical cardioversion in patients with atrial fibrillation (AF) is associated with an increased risk of stroke. We compared a transesophageal echocardiography (TEE)-guided strategy with a conventional strategy in patients with AF > 2 days' duration undergoing electrical cardioversion over a 6-month follow-up.

METHODS

The ACUTE study was a multicenter, randomized, clinical trial, with 1222 patients. Six-month follow-up was available in 1034 patients (85%), 525 in the TEE group and 509 in the conventional group. The primary composite end points were cerebrovascular accident, transient ischemic attack, and peripheral embolism at 6 months, which was a prespecified time point. Secondary end points were hemorrhage, mortality, and sinus rhythm.

RESULTS

At 6 months, there was no difference in composite embolic events between the TEE group and the conventional group (10 [2%] vs 4 [0.8%]; risk ratio (RR) 2.47, 95% CI 0.78-7.88; P = .11). However, the hemorrhagic rate was significantly lower in the TEE group (23 [4.4%] vs 38 [7.5%]; RR 0.58, 96% CI 0.35-0.97; P = .04). There was no difference between the 2 treatment groups in all-cause mortality (21 [4%] vs 14 [2.8%]; RR 1.48, 95% CI 0.76-2.92; P = .25) and in the occurrence of normal sinus rhythm between the 2 groups (305 [62.2%] vs 280 [58.1%]; P = .51). Sinus rhythm at 6 months was more common in the TEE-guided group, in those patients who had direct current cardioversion (238 [62.5%] vs 151 [53.9%]; P = .03).

CONCLUSION

The TEE-guided strategy may be considered a clinically effective alternative to a conventional anticoagulation strategy for patients with AF of > 2 days' duration undergoing electrical cardioversion over a 6-month period.

Usefulness of transoesophageal echocardiography before cardioversion in patients with atrial fibrillation and different anticoagulant regimens

OBJECTIVES

To evaluate the prevalence of atrial thrombi in patients with atrial fibrillation undergoing different anticoagulation regimens before cardioversion; to evaluate the usefulness of transoesophageal echocardiography (TOE) guided cardioversion to prevent thromboembolic complications; and to correlate the presence of atrial thrombi with clinical and echocardiographic data.

METHODS

757 consecutive patients admitted as candidates for cardioversion of atrial fibrillation were enrolled in the study. They were divided into four groups: effective conventional oral anticoagulation, short term anticoagulation, ineffective oral anticoagulation or subtherapeutic anticoagulation, and effective oral anticoagulation with a duration of < 3 weeks for various clinical reasons. All patients underwent TOE before cardioversion; in the presence of atrial thrombi or extreme left atrial echo contrast, cardioversion was postponed. The incidence of thromboembolic events was evaluated after cardioversion.

RESULTS

Atrial thrombi were detected in 48 of the 757 (6.3%) patients. No significant differences in the percentage of atrial thrombosis were found in the four study groups. Patients with atrial thrombosis were older and had a higher percentage of mitral prosthetic valves, lower left ventricular ejection fraction, more severe atrial spontaneous echo contrast, and lower Doppler left atrial appendage velocities. 648 patients were scheduled for cardioversion. Cardioversion was successful in 89% of patients without any major thromboembolic event.

CONCLUSIONS

The prevalence of atrial thrombosis before cardioversion despite different treatments with anticoagulants is about 7% and a TOE guided approach may prevent the risk of embolic events.

Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

BACKGROUND

In patients with atrial fibrillation (AF) eligible for electrical cardioversion (C), the guided approach with transesophageal echocardiography (TEE) allows to avoid the 3 weeks of recommended precardioversion anticoagulation therapy. However, after sinus rhythm restoration, at least other 4 weeks of oral anticoagulation therapy are indicated, due to the postcardioversion thromboembolic risk related to left atrial (LA) and left atrial appendage (LAA) stunning. The aim of this study was to prospectively assess the effectiveness and the safety of anticoagulation therapy discontinuation 7 days after C using low-molecular-weight heparins (LMWH) in a selected group of patients who underwent a pre-C and 7 days post-C TEE evaluation.

METHODS

One hundred one patients (74 patients with nonvalvular AF and 27 patients with atrial flutter lasting >48 h and history of AF) were enrolled into the study. Two patients refused the TEE, therefore, in 99/101, we performed a first TEE and, within 24 h, a C if there were no LAA thrombi, complex aortic plaques or severe spontaneous echocontrast. After C and 7 days of home-administered enoxaparin, a second TEE was carried out. In the absence of any new thrombi, severe spontaneous echocontrast and/or low emptying velocity of LAA, the therapy with enoxaparin was stopped; otherwise, anticoagulation therapy with enoxaparin was overlapped with oral anticoagulation and continued for at least 3 weeks. All patients were clinically followed at 1, 6 and 12 months after C.

RESULTS

Sinus rhythm was restored in 68/99 patients after successful C. The second TEE was carried out in 53 patients. At 1 month follow-up, no thromboembolic events were recorded either in patients at risk who had continued the oral anticoagulant therapy for at least 3 weeks or in those who suspended LMWH after 7 days post-C TEE. Between the 2nd and 12th month, three ischemic strokes occurred, all in the group of patients who had anticoagulation therapy for at least 3 weeks and had shown LAA velocity <25 cm/s at first or second TEE. No thromboembolic events were recorded in patients with normal LAA velocity; conversely, among the patients who had shown low LAA velocity at either TEE, three suffered from ischemic stroke. In two of these three patients, low LAA velocity was detected only at post-C TEE.

CONCLUSIONS

A brief anticoagulation therapy using LMWH appears to be safe and feasible. The 7 days post-C TEE can well-define patients without LAA stunning at low thromboembolic risk, who may take advantage of an early interruption of enoxaparin as an alternative to long oral anticoagulation. The LAA stunning, even in the absence of other thromboembolic risk factors, could select a group of patients at high risk who should continue oral anticoagulation indefinitely or until signs of LAA dysfunction disappear.

Stunning of the Left Atrium after Conversion of Atrial Fibrillation: Predictor for Maintenance of Sinus Rhythm?

Recurrence of atrial fibrillation (AF) after cardioversion (CV) to sinus rhythm (SR) is determined by various clinical and echocardiographic parameters. The aim of this study was to determine the value of mitral inflow A-wave velocity, performed at 24 hours after CV in estimation of AF recurrence. The study group consisted of 187 consecutive patients with nonvalvular atrial fibrillation, who had been cardioverted to SR from 1998 to 2000. Transthoracic echocardiography was performed in all cases recruited for the study 24 hours after CV. Left atrial (LA) diameter, left ventricular ejection fraction, and mitral inflow A-wave velocity were measured. The patients were evaluated in five groups according to their recurrence time (<30 days, 31-90 days, 91-180 days, 181-365 days, and >365 days). Maintenance of SR was determined to have a negative linear correlation with age (r =-0.97, P = 0.006), LA diameter (r =-0.93, P = 0.02), and AF duration (r =-0.93, P = 0.02), while having a positive linear correlation with mitral inflow A-wave velocity (r = 0.96, P = 0.008). In the maintenance of sinus rhythm, age, LA diameter, and AF duration were not affected from the method of CV, while mitral inflow A-wave velocity was found to be affected with the method of CV. No relationship was determined between mitral inflow A-wave velocity and the maintenance of sinus rhythm in those performed electrical cardioversion, while frequency of recurrence was found to be higher in those with slow mitral inflow A-wave velocity who were performed pharmacological cardioversion (r = 0.89, P = 0.004). In conclusion, age, duration of AF, LA diameter, and the mitral inflow A-wave velocity can be used to predict the maintenance of SR after CV.

Atrial Fibrillation: Modern Concepts and Management

Atrial fibrillation (AF) is a common cardiac arrhythmia responsible for significant morbidity and mortality. In recent years, progress has been made in determining the genetic abnormalities that may lead to AF. New trials have shown that rate control and anticoagulation are acceptable as a primary treatment strategy in many patients who have a high risk of recurrence. Newer and safer antiarrhythmics are now available. Pacemaker and implantable cardiac defibrillator technology is rapidly evolving and may play a significant role in future treatment and prevention of AF. Direct thrombin inhibitors are likely to add a user-friendly option to the current standard therapy for stroke prevention.

Anticoagulation during cardioversion in patients with atrial fibrillation: current clinical practice

The role of anticoagulation in the long-term treatment of atrial fibrillation (AF) has been well established in prospective randomized trials. Less certainty exists on the optimal anticoagulation in the setting of AF cardioversion. Current guidelines advocate anticoagulation for 3-4 weeks before and after cardioversion of AF of >48 hours' duration. Alternatively, early cardioversion may be performed after exclusion of left atrial thrombi by transesophageal echocardiography. However, with conventional anticoagulation, the risk of bleeding has to be considered and, thus, anticoagulation is frequently underused in the clinical setting. Moreover, the role of cardioversion has been questioned by recent trials suggesting no benefit of sinus rhythm restoration over rate control in AF. This article aims to summarize the currently available data on anticoagulation in cardioversion of AF in the context of these new studies and points to some new drugs such as low-molecular weight heparins and oral thrombin inhibitors that may lead to safer anticoagulation for prevention of thromboembolic complications of AF in the future.

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.

Rate control in atrial fibrillation: choice of treatment and assessment of efficacy

The clinical relevance and high social costs of atrial fibrillation have boosted interest in rate control as a cost-effective alternative to long-term maintenance of sinus rhythm (i.e. rhythm control). Prospective studies show that rate control (coupled with thromboembolic prophylaxis) is a valuable treatment option for all forms of atrial fibrillation. The rationale for rate control is that high ventricular rates, frequently found in atrial fibrillation, lead to haemodynamic impairment, consisting of a variable combination of loss of atrial kick, irregularity in ventricular response and inappropriately rapid ventricular rate, depending on the type of underlying heart disease. Long-term persistence of tachycardia at a high ventricular rate can lead to various degrees of ventricular dysfunction and even to tachycardiomyopathy-related heart failure. Identification of this reversible and often concealed form of left ventricular dysfunction can permit effective management by rate (or rhythm) control. Although acute rate control (to reduce ventricular rate within hours) is still often based on digoxin administration, for patients without left ventricular dysfunction, calcium channel antagonists or beta-adrenoceptor antagonists (beta-blockers) are generally more appropriate and effective. In chronic atrial fibrillation, long-term rate control (to reduce morbidity/mortality and improve quality of life) must be adapted to patients' individual characteristics to grant control during daily activities, including exercise. According to current guidelines, the clinical target of rate control should be a ventricular rate below 80-90 bpm at rest. However, in many patients, assessment of the appropriateness of different drugs should include exercise testing and 24h-Holter monitoring, for which specific guidelines are needed. In practice, rate control is considered a valid alternative to rhythm control. Recent prospective trials (e.g. the Pharmacological Intervention in Atrial Fibrillation [PIAF] and the Atrial Fibrillation Follow-up Investigation of Rhythm Management [AFFIRM] trials) have shown that in selected patients, rate control provides similar benefits, more economically, in terms of quality of life and long-term mortality. The choice of a rate control medication (digoxin, beta-blockers, calcium channel antagonists or possibly amiodarone) or a non-pharmacological approach (mainly atrioventricular node ablation coupled with pacing) must currently be based on clinical assessment, which includes assessing the presence of underlying heart disease and haemodynamic impairment. Definite guidelines are required for each different subset of patients. Rate control is particularly tricky in patients with heart failure, for whom non-pharmacological options can also be considered. The preferred pharmacological options are beta-blockers for stabilised heart failure and digoxin for unstabilised forms.

Bleeding complications in patients with atrial fibrillation undergoing cardioversion randomized to transesophageal echocardiographically guided and conventional anticoagulation therapies

In a multicenter randomized trial, we studied a transesophageal echocardiography (TEE) guided strategy with short-term anticoagulation compared with a conventional strategy for patients with atrial fibrillation >2 days' duration and undergoing cardioversion. Composite major and minor bleeding was a predetermined secondary end point of the study. The objective of the study was to assess the incidence, location, and predictors of bleeding in the 2 treatment groups. A total of 1,222 patients were assigned to a TEE guided or conventional strategy and followed over 8 weeks. We present data on major and minor adjudicated bleeding complications for the 2 study groups during the 8-week study period. Composite major and minor bleeding complications occurred in 51 of 1,222 patients (4.2%) and were significantly lower in the TEE guided group compared with the conventional group (2.9 vs 5.5%, p = 0.025). The TEE group had fewer cancellations of cardioversion as a result of bleeding (0% vs 0.7%, p = 0.003). Major (n = 14) and minor (n = 38) bleeding complications were predominantly gastrointestinal (71.4% and 31.6%, respectively) and were associated with warfarin use. Predictors of bleeding included patient age, conventional group assignment, inpatient status, and functional status. Thus, composite major and minor bleeding complications occurred in 4.2% of the 1,222 patients and were significantly lower in the TEE guided group compared with the conventional group. Treatment variables affecting length of anticoagulant therapy in the conventional arm combined with advancing age and functional status are important concerns in patients who undergo cardioversion of atrial fibrillation.

Emergency management of atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia managed by emergency and acute general physicians. There is increasing evidence that selected patients with acute atrial fibrillation can be safely managed in the emergency department without the need for hospital admission. Meanwhile, there is significant variation in the current emergency management of acute atrial fibrillation. This review discusses evidence based emergency management of atrial fibrillation. The principles of emergency management of acute atrial fibrillation and the subset of patients who may not need hospital admission are reviewed. Finally, the need for evidence based guidelines before emergency department based clinical pathways for the management of acute atrial fibrillation becomes routine clinical practice is highlighted.

Late improvement in ventricular performance following internal cardioversion for persistent atrial fibrillation: an argument in support of concealed cardiomyopathy

The aim of the study was to evaluate the time course of atrial and ventricular function improvement following internal atrial cardioversion in patients with structural heart disease. Twenty-nine patients with chronic persistent atrial fibrillation (AF) and underlying structural heart disease were followed by serial echocardiograms performed at 1 and 6 hours, 1 day, 1, 2, and 3 weeks, and 1, 2, 3, and 6 months after successful cardioversion. Sinus rhythm was maintained at 6 months in 24 patients. Following cardioversion the time course of left atrial mechanical function (peak A wave, percent A wave filling) differed from that of left ventricular ejection fraction: peak A wave values (cm/s) increased significantly at 1 week (51 +/- 23 vs 35 +/- 15 at 1 hour, P < 0.05), percent A wave filling (%) increased significantly at 2 weeks (34 +/- 12 vs 22 +/- 9 at 1 hour, P < 0.05), whereas left ventricular ejection fraction (%) increased later (at 1 month 60 +/- 14 vs 55 +/- 14 at baseline, P < 0.05 and at 2 months 60 +/- 14 vs 56 +/- 14 at 1 hour, P < 0.05). In conclusion, restoration of sinus rhythm results in an improvement in left ventricular ejection fraction during follow-up, even in patients with structural heart disease without fast ventricular rates at baseline. The dissociation between the time course of atrial and ventricular function improvement suggests that the latter was partly due to regression of a concealed form of cardiomyopathy and/or of a ventricular dysfunction due to chronic AF.

Atrial fibrillation in the elderly: facts and management

Although atrial fibrillation is not widely known by the general public, in developed countries it is the most common arrhythmia. The incidence increases markedly with advancing age. Thus, with the growing proportion of elderly individuals, atrial fibrillation will come to represent a significant medical and socioeconomic problem. The consequences of atrial fibrillation have the greatest impact. The risk of thromboembolism is well known; other outcomes of atrial fibrillation are less well recognised, such as its relationship with dementia, depression and death. Such consequences are responsible for diminished quality of life and considerable economic cost. Atrial fibrillation is characterised by rapid and disorganised atrial activity, with a frequency between 300 and 600 beats/minute. The ventricles react irregularly, and may contract rapidly or slowly depending on the health of the conduction system. Clinical symptoms are varied, including palpitations, syncope, dizziness or embolic events. Atrial fibrillation may be paroxysmal, persistent or chronic, and a number of attacks are asymptomatic. Suspicion or confirmation of atrial fibrillation necessitates investigation and, as far as possible, appropriate treatment of underlying causes such as hypertension, diabetes mellitus, hypoxia, hyperthyroidism and congestive heart failure. In the evaluation of atrial fibrillation, cardiac exploration is invaluable, including electrocardiogram (ECG) and echocardiography, with the aim of detecting cardiac abnormalities and directing management. In elderly patients (arbitrarily defined as aged >75 years), the management of atrial fibrillation varies; it requires an individual approach, which largely depends on comorbid conditions, underlying cardiac disease, and patient and physician preferences. This management is essentially based on pharmacological treatment, but there are also nonpharmacological options. Two alternatives are possible: restoration and maintenance of sinus rhythm, or control of ventricular rate, leaving the atria in arrhythmia. Pharmacological options include antiarrhythmic drugs, such as class III agents, beta-blockers and class IC agents. These drugs have some adverse effects, and careful monitoring is necessary. The nonpharmacological approach to atrial fibrillation includes external or internal direct-current cardioversion and new methods, such as catheter ablation of specific foci, an evolving science that has been shown to be successful in a very select group of atrial fibrillation patients. Another serious challenge in the management of chronic atrial fibrillation in older individuals is the prevention of stroke, its primary outcome, by choosing an appropriate antithrombotic treatment (aspirin or warfarin). Several risk-stratification schemes have been validated and may be helpful to determine the best antithrombotic choice in individual patients.

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.

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.

Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation

BACKGROUND

The conventional treatment strategy for patients with atrial fibrillation who are to undergo electrical cardioversion is to prescribe warfarin for anticoagulation for three weeks before cardioversion. It has been proposed that if transesophageal echocardiography reveals no atrial thrombus, cardioversion may be performed safely after only a short period of anticoagulant therapy.

METHODS

In a multicenter, randomized, prospective clinical trial, we enrolled 1222 patients with atrial fibrillation of more than two days' duration and assigned them to either treatment guided by the findings on transesophageal echocardiography or conventional treatment. The composite primary end point was cerebrovascular accident, transient ischemic attack, and peripheral embolism within eight weeks. Secondary end points were functional status, successful restoration and maintenance of sinus rhythm, hemorrhage, and death.

RESULTS

There was no significant difference between the two treatment groups in the rate of embolic events (five embolic events among 619 patients in the transesophageal-echocardiography group [0.8 percent]) vs. three among 603 patients in the conventional-treatment group [0.5 percent], P=0.50). However, the rate of hemorrhagic events was significantly lower in the transesophageal-echocardiography group (18 events [2.9 percent] vs. 33 events [5.5 percent], P=0.03). Patients in the transesophageal-echocardiography group also had a shorter time to cardioversion (mean [+/-SD], 3.0+/-5.6 vs. 30.6+/-10.6 days, P<0.001) and a greater rate of successful restoration of sinus rhythm (440 patients [71.1 percent] vs. 393 patients [65.2 percent], P=0.03). At eight weeks, there were no significant differences between the two groups in the rates of death or maintenance of sinus rhythm or in functional status.

CONCLUSIONS

The use of transesophageal echocardiography to guide the management of atrial fibrillation may be considered a clinically effective alternative strategy to conventional therapy for patients in whom elective cardioversion is planned.

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.

Time course of recovery of left atrial mechanical dysfunction after cardioversion of spontaneous atrial fibrillation with the implantable atrial defibrillator

The effect of the timing of cardioversion of atrial fibrillation on left atrial mechanical function was studied in 11 patients treated with the implantable atrial defibrillator. Results of this study suggested that prompt cardioversion of spontaneous episodes of atrial fibrillation within 48 hours after onset was associated with early resolution of left atrial mechanical dysfunction seen after cardioversion.

Transesophageal echocardiography for early cardioversion of atrial fibrillation

Exclusion of thrombi in the setting of atrial fibrillation (AF) has important implications for early cardioversion. Cardioversion guided by transesophageal echocardiography (TEE) is a safe and relatively cost-effective technique with a high accuracy for detecting left-atrial thrombi. Nowadays, TEE-guided cardioversion may help to select patients suitable for early cardioversion. However, the long-term effect of early TEE-guided cardioversion on the maintenance of sinus rhythm needs to be determined.