Left Atrial Appendage Function and Abnormal Hypercoagulability in Patients With Atrial Flutter *

Antithrombotic therapy in atrial flutter: To anticoagulate or not, that is the question

Atrial fibrillation (AF) represents an arrhythmia fraught with significant morbidity, mortality, and financial burden for the health care system. Less attention is given to atrial flutter (AFL), which may occur as a stand-alone arrhythmia or coexist with AF in the same patient. Moreover, it is known that AF frequently develops after AFL ablation. Despite different pathophysiologies of AF and AFL, current guidelines provide identical indications for anticoagulation therapy in both arrhythmias, given the lack of trials in patients with AFL. This study attempts at providing an up-to-date literature review on the thromboembolic risk profile in AFL, focusing on differences between AFL and AF. Echocardiographic studies showed that the presence of spontaneous echocardiographic contrast (SEC) and thrombus are much less prevalent in patients with AFL than in those with AF. Patients with AFL had overall better left atrial appendage (LAA) function and lower coagulation marker levels than did patients with AF. Observational studies showed a significantly lower risk of stroke in patients with AFL than in those with AF. One study found a significantly higher ischemic stroke incidence in the AFL cohort only at CHA2DS2-VASc scores from 5 to 9 than in patients without AF or AFL. These findings imply that the thromboembolic risk inherent in AFL seems lower than that in AF. This should be considered in the context of a high chance of permanent AFL termination after successful cavotricuspid isthmus ablation, in contrast to the chronic clinical nature of AF. Although thromboembolic risk exists in AFL, prospective studies are warranted to establish the true prothrombotic properties of AFL, allowing the reassessment of anticoagulant treatment strategy.

Comprehensive Analysis of Anticoagulant Therapy in Patients with Isolated Atrial Flutter

Limited comparative data exist regarding the risk of cardiogenic emboli in patients with isolated atrial flutter (AFL). Some studies suggest a lower complication risk in AFL compared to atrial fibrillation (AFib), but methodological limitations and conflicting reports necessitate a comprehensive investigation. Our analysis proposes that isolated AFL carries a lower risk of ischemic events and left atrial thrombus formation than AFib. Importantly, we caution against applying stroke risk assessment approaches designed for AFib to AFL patients, as it may lead to harmful overestimations and unnecessary anticoagulant prescriptions. Furthermore, we highlight the current lack of sufficient data to determine the overall clinical benefit of prolonged anticoagulant therapy in patients with isolated AFL, especially when CHA2DS2-VASc index values are below 4. This review challenges existing perceptions, offering insights into the nuanced risk profiles of the transitional nature of isolated AFL due to the high incidence of AFib development within a year of AFL diagnosis. In conclusion, tailored risk assessments and further research are essential for precise clinical decision-making in this dynamic landscape.

Mechanisms and Prediction of Ischemic Stroke in Atrial Fibrillation Patients

Atrial fibrillation (AF) is the most common arrhythmia in adults worldwide and represents an important burden for patients, physicians, and healthcare systems. AF is associated with substantial mortality and morbidity, due to the disease itself and its specific complications, such as the increased risk of stroke and thromboembolic events associated with AF. The temporal relation between AF episodes and stroke is nonetheless incompletely understood. The factors associated with an increased thromboembolic risk remain unclear, as well as the stroke risk stratification. Therefore, in this review, we intend to expose the mechanisms and physiopathology leading to intracardiac thrombus formation and stroke in AF patients, together with the evidence supporting the causal hypothesis. We also expose the risk factors associated with increased risk of stroke, the current different risk stratification tools as well as future prospects for improving this risk stratification.

Assessment of left atrial appendage function by echocardiography

The left atrial appendage (LAA) is considered not only to be the most frequent site of thrombus formation, but also to play a pivotal role in maintaining normal cardiac function. Transesophageal echocardiography (TEE) is widely used to assess LAA function. The LAA flow velocity has been used as a surrogate for LAA function, and it varies with multiple interrelated factors including age, hemodynamics, type of arrhythmia, and antiarrhythmic interventions. Relatively great importance of LAA function is involved with intraatrial thrombus formation and subsequent thromboembolism, and thus, understanding of characteristics and behaviors of the LAA under various clinical conditions may help determine strategies against atrial thrombosis. Also, techniques other than TEE-derived Doppler to assess LAA function, such as tissue Doppler imaging, have been proposed. In this review, we introduce clinical and echocardiographic correlates of LAA function, the LAA flow velocity in particular, its significance, and how to interpret functional patterns of the LAA each relevant to specific clinical settings.

Atrial Cardiomyopathy: An Unexplored Limb of Virchow's Triad for AF Stroke Prophylaxis

The most dreaded complication of atrial fibrillation is stroke, and 70–80% of patients with AF-related stroke die or become disabled. The mechanisms of thromboembolism in AF are multifactorial, with evidence demonstrating that all three criteria of Virchow's triad are satisfied in AF: abnormal stasis of blood, endothelial damage, and hypercoagulability. Mechanistic insights into the latter two limbs have resulted in effective stroke prophylactic therapies (left atrial appendage occlusion and oral anticoagulants); however, despite these advances, there remains an excess of stroke in the AF population that may be due, in part, to a lack of mechanistic understanding of atrial hypocontractility resulting in abnormal stasis of blood within the atrium. These observations support the emerging concept of atrial cardiomyopathy as a cause of stroke. In this Review, we evaluate molecular, translational, and clinical evidence for atrial cardiomyopathy as a cause for stroke from AF, and present a rationale for further investigation of this largely unaddressed limb of Virchow's triad in AF.

Inverse Correlation Between Left Atrial Appendage Function and CHA2DS2-VASc Score in Patients with Atrial Flutter

Impaired left atrial appendage ejection fraction (LAA-EF) and peak LAA flow velocity (LAA-FV) are associated with high thromboembolic risks in patients with atrial fibrillation (AF). Herein, we examined LAA function among patients with atrial flutter (AFL) stratified by the CHA₂DS₂-VASc score using transesophageal echocardiography (TEE). Of 231 consecutive patients with typical AFL, 84 who fulfilled the inclusion criteria were enrolled. Among them, 57 had ongoing AFL and were divided into the isolated AFL (n = 38) and AFL with paroxysmal AF (PAF) (n = 19) groups, depending on whether they had sporadic AF before TEE. The remaining 27 patients with spontaneous sinus rhythm during TEE were designated as controls. Both the LAA-FV (31.9 cm/s vs. 51.5 cm/s, P = 0.004) and LAA-EF (28.4% vs. 36.5%, P = 0.024) measured during AFL were significantly lower in the AFL + PAF group than in the isolated AFL group. Significant inverse correlations between the CHA₂DS₂-VASc score and LAA-EF were identified in the AFL (P = 0.008) and AFL + PAF (P = 0.032) groups. We observed progressive LAA dysfunction in patients with AFL + PAF compared with that in patients with isolated AFL, and the LAA-EF was inversely correlated with the CHA₂DS₂-VASc score in these patients. Our findings may have implications on the application of thromboprophylactic therapy in patients with AFL.

Atrial Fibrillation: Biomarkers Determining Prognosis

Atrial fibrillation (AF) is a common cardiac arrhythmia known to incite increased thromboembolic and mortality risks, especially among patients not under anticoagulant therapy when indicated. Several routine scores exist to help stratify AF patients, such as the CHAD2DS2-VASc score and upon which physicians are based to decide whether to administer anticoagulant therapy. Being that anticoagulant regimen is a double- edged situation with both benefits and risks, decision-making process demands a definite and reliable, evidence-based set of data to rely on. Blood-based biological elements known as biomarkers are measurable indices that can provide crucial insights concerning not only underlying disease mechanisms but also prognostic and risk stratifying information. As AF is constituted by an overwhelming range of pathophysiological aspects such as inflammation, fibrosis, hypercoagulable states and myocardial damage, identifying and assessing relevant biomarkers will evidently support the clinician's prognostication efforts. The current reviewpresents studied biomarkers with proven prognostic potential in AF as well as possible enhancement of risk-scores when incorporated to them.

The prothrombotic state in atrial fibrillation: pathophysiological and management implications

Atrial fibrillation (AF) is the commonest sustained cardiac arrhythmia and is associated with significant morbidity and mortality. There is plenty of evidence available to support the presence of a prothrombotic or hypercoagulable state in AF, but the contributory factors are multifactorial and cannot simply be explained by blood stasis. Abnormal changes in atrial wall (anatomical and structural, as ‘vessel wall abnormalities’), the presence of spontaneous echo contrast to signify abnormal changes in flow and stasis (‘flow abnormalities’), and abnormal changes in coagulation, platelet, and other pathophysiologic pathways (‘abnormalities of blood constituents’) are well documented in AF. The presence of these components therefore fulfils Virchow’s triad for thrombogenesis. In this review, we present an overview of the established and professed pathophysiological mechanisms for thrombogenesis in AF and its management implications.

Atrial flutter: Clinical risk factors and adverse outcomes in the Framingham Heart Study

BACKGROUND

Few epidemiologic cohort studies have evaluated atrial flutter (flutter) as an arrhythmia distinct from atrial fibrillation (AF).

OBJECTIVE

The purpose of this study was to examine the clinical correlates of flutter and its associated outcomes to distinguish them from those associated with AF in the Framingham Heart Study.

METHODS

We reviewed and adjudicated electrocardiograms (ECGs) previously classified as flutter or AF/flutter and another 100 ECGs randomly selected from AF cases. We examined the clinical correlates of flutter by matching up to 5 AF and 5 referents to each flutter case using a nested case referent design. We determined the 10-year outcomes associated with flutter with Cox models.

RESULTS

During mean follow-up of 33.0 ± 12.2 years, 112 participants (mean age 72 ± 10 years, 30% women) developed flutter. In multivariable analyses, smoking (odds ratio [OR] 2.84, 95% confidence interval [CI] 1.54-5.23), increased PR interval (OR 1.28 per SD, 95% CI 1.03-1.60), myocardial infarction (OR 2.25, 95% CI 1.05-4.80) and heart failure (OR 5.22, 95% CI 1.26-21.64) were associated with incident flutter. In age- and sex-adjusted models, flutter (vs referents) was associated with 10-year increased risk of AF (hazard ratio [HR] 5.01, 95% CI 3.14-7.99), myocardial infarction (HR 3.05, 95% CI 1.42-6.59), heart failure (HR 4.14, 95% CI 1.90-8.99), stroke (HR 2.17, 95% CI 1.13-4.17), and mortality (HR 2.00, 95% CI 1.44-2.79).

CONCLUSION

We identified the clinical correlates associated with flutter and observed that flutter was associated with multiple adverse outcomes.

Embolic Stroke Diagnosed by Elevated D-Dimer in a Patient With Negative TEE for Cardioembolic Source

We report a case of cerebrovascular accident with thromboembolic stroke etiology in a patient who had atrial flutter and negative transesophageal echocardiography (TEE) results. The increased D-dimer levels (1877 ng/mL) initiated referral for magnetic resonance imaging and magnetic resonance angiography of the brain that showed classic recanalization of an embolic thrombus in the angular branch of the left middle cerebral distribution. The D-dimer level of this patient was normalized after 3 months of anticoagulation therapy. Although TEE is considered the gold standard for evaluation of cardiac source of embolism, exclusion of intracardiac thrombus with TEE alone does not eliminate the risk of thromboembolic events. This case highlights the utility of D-dimer as a potential adjunct in the decision-making process to guide investigation of thromboembolism, determine subsequent therapy, and hence reduce the risk of embolic stroke recurrence.

Prediction of improvement in left atrial function index after catheter ablation for atrial fibrillation

PURPOSE

Although left atrial function index is reportedly a possible predictor of hospitalization for heart failure and of stroke irrespective of the presence or not of atrial fibrillation (AF), the effects of catheter ablation on left atrial function index have not yet been reported.

METHODS

We performed catheter ablation on 55 patients (age 56.6 ± 9.6 years; 44 men; 30 with paroxysmal and 25 with persistent, long-standing AF) and evaluated them by transthoracic echocardiography preoperatively and 3 monthly for 12-24 months after catheter ablation. We then compared clinical characteristics and echocardiographic variables before catheter ablation between two groups: the 42 subjects with the most recent left atrial function index <30 and the 13 in which it was ≥30.

RESULTS

Left atrial function index improved after catheter ablation in both groups, plateauing 6 months after the procedure. Univariate analysis showed statistically significant differences in the prevalence of chronic AF and left atrial emptying fraction, diameter, and maximum and minimum volume (prevalence of chronic AF, p < 0.05; others, p < 0.01) between the groups. Multivariate analysis showed that only maximum left atrial volume predicts left atrial function index after catheter ablation (p < 0.05). In addition, we used ROC analysis to calculate a cutoff value for LA maximum volume as a good predictor and found that a good cutoff value was 63.5 mL, the sensitivity and specificity being 0.75 and 0.75, respectively.

CONCLUSIONS

Catheter ablation improves left atrial function index. However, in patients with left atrial maximum volume of over 63.5 mL on echocardiography, the index did not recover to within the normal range after catheter ablation.

Prevalence of auricular thrombosis before atrial flutter cardioversion: a 17-year transoesophageal echocardiographic study

AIMS

Prevalence of left appendage thrombosis ranges from 6 to 18% in persistent atrial fibrillation (AF). Few and low sample size studies have assessed left and right atrial thrombosis in persistent atrial flutter (AFL) and a wide variety of frequencies, from 1 to 21%, has been reported. The aim of this study was to evaluate the prevalence of atrial appendage thrombosis in a large population of patients undergoing transoesophageal echocardiography (TEE)-guided cardioversion (CV) for recent AFL onset and compare it with AF.

METHODS AND RESULTS

From 1999 to September 2014, we collected data of 1081 patients to CV: 877 affected by AF (81.1%) and 204 by AFL (18.9%). The presence of auricular thrombosis was evaluated by TEE in AF or AFL persisting for more than 48 h. The presence of appendage thrombosis, Doppler emptying velocities, and severe spontaneous echo contrast (SEC) was studied. The overall prevalence of atrial thrombosis was 9.62% (104/1081). Frequency of atrial thrombosis in AFL patients was 6.4% (13/204) vs. 10.5% among AF (92/877), P = 0.074. Comparing the two appendages, frequency of left atrial appendage thrombosis was in AFL 5.9% (12/204) vs. 9.9% (87/877) in the AF group, P = 0.07. Right atrial appendage thrombosis was present in 0.5% (1/204) in the AFL group vs. 0.8% (7/877) in the AF group, P = 0.64. Moderate to severe SEC (3+/4+) was present in 28% of AFL patients (57/204) vs. 35% of AF patients (307/877), P = 0.05.

CONCLUSION

Auricular thrombosis is not an infrequent finding in AFL before CV. Our study suggests the use of TEE screening in AFL, as well as in AF, when patients arrive to clinical attention after more than 48 h from arrhythmia onset.

Biomarkers in atrial fibrillation: an overview

Atrial fibrillation (AF) confers a raised risk of stroke and death, and this risk of adverse events is increased by the coexistence of other cardiovascular risk factors. The pathophysiology of AF is complex, involving the role of inflammation, structural remodelling with apoptosis, inflammation or fibrosis. These changes confer a prothrombotic or hypercoagulable state in this arrhythmia. Despite being easy to use for decision-making concerning oral anticoagulant therapy in AF, clinical risk scores used for stratification have shown modest capability in predicting thromboembolic events, and biomarkers may improve our identification of 'high risk' patients. Biomarkers, whether measured in the peripheral blood, urine or imaging-based may improve our knowledge of the pathophysiology of AF. Importantly these biomarkers could help in the assessment of AF prognosis. The aim of this review was to summarise the published data about biomarkers studied in AF, with focus on data from randomised prospective clinical trials and large community-based cohorts. We will also review the application of these biomarkers to prognosis on the main schemes used to help stratify risk in AF.

Thrombophilia-Related Complications in the Treatment of a Left Atrial Appendage Thrombus: A Case Report

Trans-esophageal echocardiography (TEE) revealed a left atrial appendage (LAA) thrombus in an 84-year-old woman with nonvalvular atrial fibrillation not known before our evaluation. In her medical history, there were hypertension, dyslipidemia and a previous pulmonary embolism. She was taking warfarin at time of our evaluation and presented signs and symptoms of heart failure. Together with heart failure treatment, intravenous anticoagulation with unfractionated heparin was initiated. Treatment was complicated by additional right lower limb embolic event and the LAA thrombus remained unchanged. Testing revealed heterozygosity for both the factor V Leiden and the methylenetetrahydrofolate reductase C677T mutations inducing resistance to activated protein C. The patient refused transcatheter closure of the left atrial appendage.

Antithrombotic therapy in cardiac embolism

Anticoagulation is indicated in most cardioembolic ischemic strokes for secondary prevention. In many cardiac conditions, anticoagulation is also indication for primary stroke prevention, mainly when associated to vascular risk factors. Anticoagulation should be started as soon as possible, as it is safe even in moderate acute strokes. The efficacy of early anticoagulation after cardioembolic stroke in relation to outcome has not been assessed adequately, but there is evidence from animal models and clinical studies that anticoagulation with unfractionated heparin is associated with a better outcome mediated in part by its anti-inflammatory properties.

A clinical cardiology perspective of thrombophilias

Thrombophilias, an inherited and/or acquired predisposition to vascular thrombosis beyond hemostatic needs are common in cardiovascular medicine and include systemic disorders such as coronary atherosclerosis, atrial fibrillation, exogenous obesity, metabolic syndrome, collagen vascular disease, human immunodeficiency virus, blood replacement therapy and several commonly used medications. A contemporary approach to patients with suspected thrombophilias, in addition to a very selective investigation for gain-of-function and loss-of-function gene mutations affecting thromboresistance, must consider prevalent diseases and management decisions encountered regularly by cardiologists in clinical practice. An appropriate recognition of common disease states as thrombophilias will also stimulate platforms for much needed scientific investigation.

Peri-procedural anticoagulation in patients undergoing ablation for atrial fibrillation

Radiofrequency catheter ablation is being used with increasing frequency as a strategy to manage atrial fibrillation. Patients undergoing this procedure are at increased short-term risk of thromboembolism for several days and up to 4 weeks or longer after their ablation, and anticoagulation management surrounding the ablation procedure remains controversial. Although no conclusive recommendations can be made, published guidelines and data support therapeutic anticoagulation with warfarin for 3 weeks prior and intravenous heparin during the ablation. Warfarin may either be continued through the ablation or stopped 2-5 days prior. If the latter approach is chosen, a pre-ablation bridging strategy of enoxaparin 1mg/kg twice daily is reasonable in selected patients unless the patient's bleeding risk dictates using a lower dose regimen (0.5mg/kg twice daily) or avoiding bridging altogether. Fewer data are available for post-ablation management strategies, and current practice patterns are based largely on single-center experiences in smaller, non-randomized studies. For lower risk patients (CHADS(2) 0-1), either warfarin or aspirin may be utilized without bridging. In higher thromboembolic risk patients (CHADS(2) >or=2), either enoxaparin (1mg/kg twice daily) or heparin may be started within the first 12-24h post-procedure. For patients with bleeding risk factors, enoxaparin may be subsequently reduced to 0.5mg/kg until the INR is therapeutic, although the efficacy of this lower dosing regimen has not been well studied. In accordance with national guidelines, warfarin should be continued post-ablation for a minimum of 2 months and then indefinitely in patients with a CHADS(2) score >or= 2.

Cardioembolic stroke in atrial fibrillation-rationale for preventive closure of the left atrial appendage

Atrial fibrillation is the most common cardiac arrhythmias, and a major cause of morbidity and mortality due to cardioembolic stroke. The left atrial appendage is the major site of thrombus formation in non-valvular atrial fibrillation. Loss of atrial systole in atrial fibrillation and increased relative risk of associated stroke point strongly toward a role for stasis of blood in left atrial thrombosis, although thrombus formation is multifactorial, and much more than blood flow irregularities are implicated. Oral anticoagulation with vitamin-K-antagonists is currently the most effective prophylaxis for stroke in atrial fibrillation. Unfortunately, this treatment is often contraindicated, particularly in the elderly, in whom risk of stroke is high. Moreover, given the risk of major bleeding, there is reason to be skeptical of the net benefit when warfarin is used in those patients. This work reviews the pathophysiology of cardioembolic stroke and critically spotlights the current status of preventive anticoagulation therapy. Various techniques to exclude the left atrial appendage from circulation were discussed as a considerable alternative for stroke prophylaxis.

Mechanisms of thrombogenesis in atrial fibrillation: Virchow's triad revisited

Atrial fibrillation is the most common sustained cardiac arrhythmia, which is associated with a high risk of stroke and thromboembolism. Increasing evidence suggests that the thrombogenic tendency in atrial fibrillation is related to several underlying pathophysiological mechanisms. Abnormal changes in flow are evident by stasis in the left atrium, and seen as spontaneous echocontrast. Abnormal changes in vessel walls-essentially, anatomical and structural defects-include progressive atrial dilatation, endocardial denudation, and oedematous or fibroelastic infiltration of the extracellular matrix. Additionally, abnormal changes in blood constituents are well described, and include haemostatic and platelet activation, as well as inflammation and growth factor changes. These changes result in the fulfilment of Virchow's triad for thrombogenesis, and accord with a prothrombotic or hypercoagulable state in this arrhythmia. In this Review, we present an overview of the established and purported mechanisms for thrombogenesis in atrial fibrillation.

Acute anticoagulation adjustment in patients with atrial fibrillation at risk for stroke: approaches, strategies, risks and benefits

The acute management of anticoagulation in patients with atrial fibrillation to prevent stroke and other thromboembolic complications includes the use of individualized strategies tailored to the patient and based on the situation (cardioversion, surgeries, dental procedures, cardiac interventions, other invasive procedures and initiation of, or adjustment to, warfarin dosing). The vast range of choices can cause confusion and few randomized controlled clinical trials in this area provide adequate guidance. Chronic anticoagulation management is more straightforward since clinical evidence is ample, randomized clinical trial data provides cogent informaiton and guidelines have been established. Acute management of anticoagulation in patients with atrial fibrillation to prevent thromboembolic complications is often unrecognized but is emerging as a crucial, but challenging, and increasingly complex aspect of the care of patients with atrial fibrillation. This review addresses issues regarding such patients who may be at risk for stroke and require acute adjustments of anticoagulation (in light of, or in lieu of, chronic anticoagulation). Several promising new strategies are considered in light of established medical care. This analysis provides practical recommendations based on available data and presents results from recent investigations that may provide insight into future strategies.

Thrombophilia in ischemic stroke subtypes: implications for treatment

The current understanding of thrombogenesis is modeled on Virchow's triad: stasis, hypercoagulability, and vessel wall injury. There is a dynamic (always changing) nonlinear interaction between the vascular wall, blood components, and flow, which at times defined "pathologic" leads to thrombosis or hemorrhage, at other times called "healthy" to normal hemostasis. The triad named after Virchow was not designated as such in Virchow's work. Instead, Virchow showed that thrombosis itself leads to endothelial damage, hypercoagulability, and stasis. Thus, cause and effect regarding the elements of Virchow's triad and thrombosis become indistinguishable if linearity is considered mandatory. Considering a nonlinear relation solves this problem. In the real patient, each element is present to a degree. At every moment in time, the direction of coagulation (toward hemostasis, thrombosis, or hemorrhage) and the dynamic of interaction of the elements of the triad change. The complexity and nonlinearity of the thrombotic context is evident. These facts suggest a new venue for diagnostic classification of stroke (ischemic and hemorrhagic) by causation and have implications for its prevention and treatment. Clinical and laboratory evidence can be gathered for the elements of Virchow's triad as well as for fibrinolysis and thrombosis. Mathematical methods other than probability-based statistics can represent the measured presence of these elements to a degree and their nonlinear relationship. These include, but may not be limited to, Riemannian geometry, fuzzy logic, cellular automata, and infinitesimals, all proscribed by evidence-based medicine. However, by using these methods, diagnosis and treatment measures for stroke can be built on a causal rather than risk methodology, individualizing medical decisions to the patient. All current clinical guidelines are based on linear methods of probability-based statistics and group-based data. The therapeutic choice of antithrombotic therapy in the individual patient for whom measured elements of thrombogenesis are available rests on the knowledge and expertise of the treating physician.

Biomarkers in Atrial Fibrillation: Investigating Biologic Plausibility, Cause, and Effect

Atrial fibrillation, an increasingly common arrhythmia whose prevalence will reach epidemic proportions over the next two decades, is characterized by atrial/atrial appendage inflammation, fibrosis, remodeling, and endocardial thrombosis. Biomarkers measured within the peripheral circulation reflect these pathobiologic events with evidence of heightened thrombin generation and activity, platelet activity, fibrin formation, endocardial injury, inflammatory mediator release, and reduced fibrinolytic potential Unfortunately, the correlation between traditional biomarkers and clinical events is weak at best, as is their ability to predict successful treatment (prevention of cardioembolism) with antithrombotic agents. Future efforts devoted to the investigation of cellular biomarkers will likely provide greater practical yield and insights concerning the development, diagnosis, prognosis, and management of atrial fibrillation.

Prolonged Activation of Hemostatic Markers Following Conversion of Atrial Flutter to Sinus Rhythm

BACKGROUND

It remains controversial whether prophylactic anticoagulation for embolism is required in patients with atrial flutter (AFL) prior to and following cardioversion as in patients with atrial fibrillation. To evaluate the potential prothrombotic state following cardioversion of AFL, concentrations of hemostatic markers were determined before and after conversion to sinus rhythm (SR).

METHODS AND RESULTS

In 12 patients (mean age 68 years) with AFL who underwent transesophageal echocardiography in the plasma concentrations of markers for platelet activity (platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG)), thrombotic status (thrombin-antithrombin III complex (TAT) and prothrombin fragments 1 and 2 (F1+2)) and fibrinolytic status (D-dimer and plasmin-alpha(2)-plasmin inhibitor complex (PIC)) were determined during AFL, and 3 days and 7 days after restoration of SR. Left atrial appendage (LAA) blood flow velocity was lower immediately after than before restoration of SR (29+/-11 vs 41+/-23 cm/s, p<0.05). Three patients developed left atrial spontaneous echo contrast immediately after restoration of SR. Although the concentrations of the markers of platelet activity did not change after restoration of SR, those of TAT and PIC increased 7 days after restoration of SR as compared with during AFL (p<0.05).

CONCLUSIONS

AFL patients have a potential risk for thromboembolism after restoration of SR and therefore anticoagulation might be required in selected patients.