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

External validation of a novel transthoracic echocardiographic tool in predicting left atrial appendage thrombus formation in patients with nonvalvular atrial fibrillation

BACKGROUND

A recent study demonstrated that in patients with nonvalvular atrial fibrillation (AF), a ratio of left ventricular ejection fraction (LVEF) to the left atrial volume index (LAVI) of <1.5 has 100% sensitivity for detecting left atrial appendage (LAA) thrombus. We sought to validate this prediction tool in an external cohort.

METHODS

We conducted a cohort study of consecutive AF patients who underwent transoesophageal echocardiogram (TEE) to 'rule-out' LAA thrombus and had a prior transthoracic echocardiogram (TTE). The LAVI and LVEF were measured to calculate LVEF/LAVI ratio. The sensitivity and specificity of LVEF/LAVI <1.5 were calculated.

RESULTS

Among 215 subjects, 19 (8.8%) had LAA thrombus and also had a higher mean CHADS2 score (2.5 vs. 1.9, P = 0.04), lower mean LVEF (24 vs. 44%, P < 0.001), higher mean LAVI (44 mL/m2 vs. 30 mL/m2, P < 0.001), and higher prevalence of cardiac failure (79 vs. 52%, P = 0.02). The LVEF and LAVI were found to be independent predictors of LAA thrombus (P < 0.05). The LVEF/LAVI ratio diagnosed LAA thrombus with an area under the curve = 0.83 by the receiver operator characteristics curve analysis (P < 0.001). All 19 (100%) subjects with LAA thrombus had LVEF/LAVI <1.5 vs. 87 (44%) among those without LAA thrombus (P < 0.001). The sensitivity and specificity of LVEF/LAVI <1.5 were 100 and 55.6%, respectively.

CONCLUSION

This investigation validates a simple TTE prediction rule to exclude the diagnosis of LAA thrombus, which may obviate the need for pre-cardioversion TEE in selected patients with nonvalvular AF.

Right atrial appendage thrombus found in a patient in normal sinus rhythm with normal right ventricular systolic function

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

Persistent atrial fibrillation is associated with worse prognosis than paroxysmal atrial fibrillation in acute cerebral infarction

Background and Purpose. We hypothesized that patients with persistent atrial fibrillation (AF) suffer from more severe cerebral infarction than patients with paroxysmal AF due to differences in clot structure and volume. Methods. This study includes consecutive patients with acute cerebral infarction and persistent or paroxysmal AF documented by ECG any time prior to stroke onset. The National Institute of Health Stroke Scale (NIHSS) was used to assess stroke severity on admission. Short-term outcome was determined by the modified Rankin scale (mRS) score, Barthel index, and NIHSS score 7 days after stroke onset. Risk factors were registered on admission. Eligible patients were treated with thrombolysis. Results. In total, 141 (52%) patients had paroxysmal AF, and 129 (48%) patients had persistent AF. NIHSS score on admission, mRS score at day 7, and mortality were significantly higher among patients with persistent AF. Thrombolysis was less effective in patients with persistent AF. Conclusions. Our study shows that patients with persistent AF and acute cerebral infarction have poorer short-term outcome than patients with paroxysmal AF. Differences in clot structure or clot volume may explain this.

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.

The role of repeat transesophageal echocardiography in patients without atrial thrombus prior to cardioversion or ablation

BACKGROUND

Cardioversion (CV) and radiofrequency catheter ablation (RFA) are often used to restore sinus rhythm in patients with atrial fibrillation (AF). These procedures are associated with a risk for stroke. The use of transesophageal echocardiography (TEE) to guide the management of AF is a validated strategy for patients in whom CV is planned, as well patients before RFA. For patients in whom the initial procedure fails, repeat TEE is often performed before repeat CV or RFA. The aim of this study was to test the hypothesis that patients with initial negative results on TEE would be unlikely to have thrombi detected on subsequent TEE and thus may avoid repeat procedures.

METHODS

A total of 2,999 patients with AF were identified via retrospective review who had undergone TEE before CV or RFA, and 418 of these individuals underwent repeat TEE. After excluding patients who underwent repeat TEE >365 days from the initial study (n = 135) and those with thrombi on initial TEE (n = 20), 263 patients who had underwent two or more examinations were identified and analyzed.

RESULTS

Of 263 eligible patients, two (0.8%; 95% confidence interval, 0.21-2.7%) had thrombi on subsequent TEE.

CONCLUSIONS

Fewer than 1% of patients with AF with negative results on baseline TEE had thrombi detected on repeat TEE before subsequent CV or RFA. Thus, it may be possible to selectively screen patients to identify those at low risk for developing thrombi subsequent to negative results on initial TEE, especially if patients are in sinus rhythm. These results suggest the need for a prospective trial to definitively answer the question regarding repeat TEE in low-risk patients.

Trends in the use of electrical cardioversion for atrial fibrillation: influence of major trials and guidelines on clinical practice

BACKGROUND

The purpose of the present study was to assess the trends in the use of ECV following published studies that had compared rhythm and rate control strategies on atrial fibrillation (AF), and the recommendations included in the current clinical practice guidelines.

METHODS

The REVERCAT is a population-based assessment of the use of electrical cardioversion (ECV) in treating persistent AF in Catalonia (Spain). The initial survey was conducted in 2003 and the follow-up in 2010.

RESULTS

We observed a decrease of 9% in the absolute numbers of ECV performed (436 in 2003 vs. 397 in 2010). This is equivalent to 27% when considering population increases over this period. The patients treated with ECV in 2010 were younger, had a lower prevalence of previous embolism, a higher prevalence of diabetes, and increased body weight. Underlying heart disease factors indicated, in 2010, a higher proportion of NYHA ≥ II and left ventricular ejection fraction <30%. We observed a reduction in the number of ECV performed in 16 of the 27 (67%) participating hospitals. However, there was an increase of 14% in the number of procedures performed in tertiary hospitals, and was related to the increasing use of ECV as a bridge to AF ablation. Considering the initial number of patients treated with ECV, the rate of sinus rhythm at 3 months was almost unchanged (58% in 2003 vs. 57% in 2010; p=0.9) despite the greater use of biphasic energy in 2010 and a similar prescription of anti-arrhythmic drugs.

CONCLUSIONS

Although we observed a decrease in the number of ECVs performed over the 7 year period between the two studies, this technique remains a common option for treating patients with persistent AF. The change in the characteristics of candidate patients did not translate into better outcomes.

Subclinical thyroid disease and the incidence of hypertension in pregnancy

OBJECTIVE

To estimate the possibility of long-term effects of subclinical thyroid dysfunction on hypertension and other cardiovascular-related conditions during pregnancy.

METHODS

This is a secondary analysis of a prospective prenatal population-based study in which serum thyroid-function analytes were measured from November 2000 through April 2003. Women with evidence of overt thyroid disease were excluded. The remaining women were classified as being euthyroid, having subclinical hyperthyroid, or having subclinical hypothyroid, and the frequency of pregnancy-associated hypertensive disorders was compared between these groups.

RESULTS

Pregnancy outcomes in 24,883 women were analyzed for pregnancy hypertension, classified as gestational hypertension, mild preeclampsia, or severe preeclampsia. The incidence of hypertensive disorders were compared between the three cohorts. The overall incidences of hypertension in pregnancy were 6.2%, 8.5%, and 10.9% in the subclinical hyperthyroid, euthyroid, and subclinical hypothyroid groups, respectively, and were found to be significant when unadjusted (P=.016). After adjusting for confounding factors, there was a significant association between subclinical hypothyroidism and severe preeclampsia (adjusted odds ratio 1.6, 95% confidence interval 1.1-2.4; P=.03).

CONCLUSION

Women with subclinical hypothyroidism identified during pregnancy have an increased risk for severe preeclampsia when compared with euthyroid women.

LEVEL OF EVIDENCE

II.

Thyroid stimulating hormone, independent of thyroid hormone, can elevate the serum total cholesterol level in patients with coronary heart disease: a cross-sectional design

Background

The relationship between TSH and the lipid profile is contradictory because few studies have excluded the potential influence of the thyroid hormones (TH). The aim of the present study was to evaluate the relationship between serum TSH levels and the lipid profile independent of TH.

Methods

1302 CHD patients diagnosed by coronary angiography were retrospectively studied. The prevalence and distribution of thyroid dysfunction were analyzed first. To assess the impact of TSH on serum lipids, Pearson’s correlation analysis was performed after adjustments for classic factors and TH. To calculate the extent of the effect of TSH on the serum cholesterol level, the partial least squares method and additional statistical methods were used.

Results

After the exclusions, a total of 568 patients (270 males and 298 females with a mean age of 63.56 ± 11.376 years) were selected. The prevalence of thyroid dysfunction among the patients was 18.66%, and the prevalence of hypothyroidism (15.32%) was higher than that of hyperthyroidism (3.34%). Even after adjusting for confounding factors, such as sex, age, smoking status, fasting plasma glucose levels and TH, a significant positive impact of TSH on the serum total cholesterol (TC) level was revealed (r = 0.095, p = 0.036). Each 1 mIU/L increase in the TSH level might be linked to a 0.015580712 mmol/L elevation of the serum TC value.

Conclusions

TSH can increase the TC level in CHD patients independent of TH. The present study suggests a potential physiological role of TSH and the importance of maintaining an appropriate TSH level in CHD patients.

The role of echocardiography in the management of the sources of embolism

The echocardiographic diagnosis of cardiac thrombi, vegetations and tumors as well as the identification of predisposing conditions such as patent foramen ovale, aortic atherosclerosis and other minor causes (e.g., mitral valve prolapse, mitral and aortic valve calcification) have crucial clinical relevance, affecting the choice of surgery and/or of pharmaceutical therapy in the setting of patients presenting embolism. The echocardiographic assessment helps not only for the retrospective diagnosis of sources of embolism but also for the prevention of events in asymptomatic patients. Echocardiography can also distinguish normal variants and artifacts from cardiac masses and tumors. Echocardiographic characterization/typology of cardiac sources of embolism is currently below par when compared with cardiac MRI, the current gold standard. Nevertheless, echocardiography remains the 'first-line' imaging tool, because of its low cost and the possibility to add easily available, functional and structural information at the patient's bedside.

Outcome of Patients Discharged after their First Detected Episode of Atrial Fibrillation

Atrial fibrillation (AF) is the most frequent supraventricular arrhythmia with an approximative prevalence of 1 % in the general population and above 6 % in the elderly. After a first AF diagnosis, the hospitalization rate is markedly increased. Management of a first AF episode is different depending on the clinical status of patients. Practical guidelines developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society are available for the management of these patients. A four-step decisional scheme must be followed in the management of a first recent AF episode: need for a short- and long-term anticoagulation, define a rythmologic strategy (rhythm or rate control), select the weapon (drug, device or ablation) and reconsider the strategy if needed. After a first uncomplicated paroxysmal AF episode, guidelines recommend that prescription of antiarrhythmics must be avoided and anticoagulation is optional. After a first persistent AF episode, guidelines recommend to either respect or reduce the arrhythmia. Prescription of antiarrhythmics and anticoagulation is also optional depending on the patient?s condition. In case of the AF reduction decision, anticoagulation must be tailored preliminary to this reduction. AF recurrence rate varies depending on the patient?s condition, and the risk of stroke assessed by the CHA₂DS₂-VASc score might be similarly considered for both paroxysmal and persistent AF.

Antithrombotic therapy for atrial fibrillation: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

The risk of stroke varies considerably across different groups of patients with atrial fibrillation (AF). Antithrombotic prophylaxis for stroke is associated with an increased risk of bleeding. We provide recommendations for antithrombotic treatment based on net clinical benefit for patients with AF at varying levels of stroke risk and in a number of common clinical scenarios.

METHODS

We used the methods described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines article of this supplement.

RESULTS

For patients with nonrheumatic AF, including those with paroxysmal AF, who are (1) at low risk of stroke (eg, CHADS(2) [congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack] score of 0), we suggest no therapy rather than antithrombotic therapy, and for patients choosing antithrombotic therapy, we suggest aspirin rather than oral anticoagulation or combination therapy with aspirin and clopidogrel; (2) at intermediate risk of stroke (eg, CHADS(2) score of 1), we recommend oral anticoagulation rather than no therapy, and we suggest oral anticoagulation rather than aspirin or combination therapy with aspirin and clopidogrel; and (3) at high risk of stroke (eg, CHADS(2) score of ≥ 2), we recommend oral anticoagulation rather than no therapy, aspirin, or combination therapy with aspirin and clopidogrel. Where we recommend or suggest in favor of oral anticoagulation, we suggest dabigatran 150 mg bid rather than adjusted-dose vitamin K antagonist therapy.

CONCLUSIONS

Oral anticoagulation is the optimal choice of antithrombotic therapy for patients with AF at high risk of stroke (CHADS(2) score of ≥ 2). At lower levels of stroke risk, antithrombotic treatment decisions will require a more individualized approach.

A high normal TSH level is associated with an atherogenic lipid profile in euthyroid non-smokers with newly diagnosed asymptomatic coronary heart disease

Background

Serum lipid profiles may be influenced by thyroid function, but the detailed mechanism remains unclear. Increasing evidence suggests that thyrotropin (TSH) may exert extra-thyroidal effects. The goal of this study was to evaluate the relationship between serum TSH levels and the lipid profiles in euthyroid non-smokers with newly diagnosed asymptomatic coronary heart disease (CHD).

Methods

This was a retrospective study of 406 euthyroid non-smokers (187 males and 219 females) with newly diagnosed asymptomatic CHD from 2004 to 2010 in Jinan, China. Lipid parameters and the levels of TSH, FT3, and FT4 were determined. Multiple linear regression analysis and Logistic regression analysis were used to assess the influence of TSH on the lipid profiles and the risks of dyslipidemia.

Results

The TSH level, even within the normal range, was positively and linearly correlated with total cholesterol (TC), non-high density lipoprotein cholesterol (non-HDL-C) and triglycerides (TG) (Beta = 0.173, 0.181 and 0.103, respectively, P < 0.01 in all). With 1 mIU/L rise of TSH, the levels of TC, TG and non-HDL-C will increase by 1.010, 1.064, and 1.062 mmol/L, respectively. The odds ratio of hypercholesterolemia and hypertriglyceridemia with respect to the serum TSH level was 1.640 (95% CI 1.199-2.243, P = 0.002) and 1.349 (95% CI 1.054-1.726, P = 0.017), respectively.

Conclusions

TSH levels were correlated in a positive linear manner with the TC, non-HDL-C and TG levels in euthyroid non-smokers with newly diagnosed asymptomatic CHD. TSH in the upper limits of the reference range might exert adverse effects on lipid profiles and thus representing as a risk factor for hypercholesterolemia and hypertriglyceridemia in the context of CHD.

Left atrial blood stasis and Von Willebrand factor-ADAMTS13 homeostasis in atrial fibrillation

OBJECTIVE

Left atrial blood stasis is associated with increased risk for left atrial appendage thrombus (LAAT) and stroke in atrial fibrillation (AF). Von Willebrand factor (VWF) is associated with thromboembolism in AF. VWF thrombogenic activity is proportional to multimer size, which is regulated by VWF-cleaving protease (ADAMTS13).

METHODS AND RESULTS

To assess the association between left atrial blood stasis and VWF-ADAMTS13 system, plasma VWF antigen (VWF:Ag), VWF activity (VWF:Act), and ADAMTS13 activity were measured in 414 consecutive patients with nonvalvular AF (age 63±13 years; 25% women) and in 100 patients (age 64±14 years; 39% women) with normal sinus rhythm. Spontaneous echocardiographic contrast (SEC), left atrial appendage emptying velocity, and LAAT were assessed by transesophageal echocardiography. Presence and intensity of SEC varied directly with VWF:Ag and VWF:Act but not with ADAMTS13 activity. AF patients with LAAT had higher VWF:Ag (200±61 versus 155±52, P=0.0006) and VWF:Act (179±57 versus 141±51 P=0.0026) compared with those without LAAT. VWF:Ag and VWF:Act were independent predictors of LAAT after adjustment for CHADS2 score (P=0.0179 and P=0.0497, respectively).

CONCLUSION

The association between VWF and SEC may explain the thrombotic propensity in AF. Elevated VWF:Ag may help identify AF patients at risk for LAAT.

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.

Measurement of left atrial appendage size by transesophageal echocardiography

Transesophageal echocardiography (TEE) is the most common imaging method for evaluating left atrial morphology. Recent advances in 64-slice multidetector computed tomography (64-MDCT) allow accurate measurement of left atrial appendage (LAA) volume. The aim of this study was to evaluate the accuracy of LAA sizing by TEE in comparison with 64-MDCT in patients with atrial fibrillation. Electrocardiogram-gated 64-MDCT and TEE were performed within 2 days in 18 consecutive patients (63 ± 9 years old, 12 males, 5 paroxysmal atrial fibrillation) with nonvalvular atrial fibrillation. LAA area and LAA volume were measured at end-systole by TEE and 64-MDCT, respectively. The largest LAA area was measured on TEE image. Five patients were in sinus rhythm during examinations. In all patients, LAA was clearly visualized; the largest area of LAA was 9.3 ± 3.9 mm(2) and the LAA volume was 21.6 ± 7.5 ml. A significant correlation between LAA area and LAA volume was observed (p = 0.0003, r = 0.75). TEE allows a detailed evaluation of the LAA structure by two-dimensional imaging. LAA size could be evaluated by TEE despite its morphological complexity, i.e., sac-like or multilobed structure.

Atrial fibrillation: established and innovative methods of evaluation and treatment

BACKGROUND

5% to 8% of 70-year-olds and some 10% of persons over age 80 have atrial fibrillation (AF).

METHODS

Selective literature review.

RESULTS

New scoring schemes (CHA(2)DS(2)-VASc score, HAS-BLED score) have been introduced to enable more accurate estimation of the risk of stroke and hemorrhage in patients with AF. These scores are calculated on the basis of clinical data (left ventricular dysfunction, hypertension, age, diabetes, prior stroke, vascular diseases, sex, renal or hepatic dysfunction, bleeding, labile INR values, consumption of medications and alcohol) and are used to determine the potential indication for, and appropriate type of, anticoagulation in the individual AF patient. Hemodynamically unstable patients with rapid AF should undergo DC cardioversion at once. Patients with permanent AF should be given beta-blockers, calcium antagonists, or digitalis for rate control, with a target rate below 110/minute. A recently introduced drug, dronedarone, is used for rhythm control and has relatively few side effects. Patients with AF and impaired left ventricular function should be given amiodarone. Rhythm control has not been found to prolong life any more than rate control. Patients with a CHA(2)DS(2)-VASc score of 2 or above should be orally anticoagulated. Those with a score of 1 can be treated with aspirin (75 to 325 mg daily); those with a score of 0 do not need antithrombotic treatment. A HAS-BLED score of 3 or above is associated with a high risk of bleeding. Pulmonary vein isolation is an established method of treating symptomatic AF, with a success rate of 60% to 80%. Surgical procedures are possible in AF patients who need additional cardiac surgery.

CONCLUSION

The treatment strategy for AF must be individualized on the basis of the patient's clinical manifestations. The mainstay of treatment is anticoagulation; the indication for anticoagulation depends on the patient's age, underlying disease, and left ventricular function.

Serum TSH level in healthy Koreans and the association of TSH with serum lipid concentration and metabolic syndrome

BACKGROUND/AIMS

The proper treatment of subclinical hypothyroidism and the normal range of serum thyroid stimulating hormone (TSH) concentration are intensely debated. However, few reports have investigated TSH concentrations in Asian ethnic groups. Therefore, the present study was designed to define the TSH reference range in a Korean population and to investigate the metabolic significance of TSH concentration.

METHODS

We enrolled patients who underwent medical examination at the CHA Bundang Medical Center. Anthropometric data were evaluated, and serum TSH, free T4, and lipid profiles were assayed.

RESULTS

A total of 7,270 subjects were included. Mean TSH concentration of the study population was 1.82 ± 0.95 mU/L, and we observed a sex-related difference in TSH concentration (male, 1.67 ± 0.87 mU/L; female, 2.02 ± 1.01 mU/L; p < 0.01). When the 2.5 and 97.5 percentiles were calculated, 95% TSH reference limits were 0.52-4.29 mU/L. TSH concentration was higher in elderly subjects, during winter, in postmenopausal women, and in obese males. Moreover, TSH showed significantly positive correlations with serum total cholesterol, triglyceride, and low density lipoprotein cholesterol regardless of sex, age, season, obesity, or menopausal status (all p < 0.01). Finally, TSH concentration was positively related to the prevalence of metabolic syndrome.

CONCLUSIONS

We demonstrated the association between TSH concentration within the normal reference range and serum lipid levels. TSH concentration varies according to sex, age, season, and body mass index (only in males). Moreover, high normal TSH levels were significantly associated with an increased prevalence of metabolic syndrome, which may be of importance when evaluating subjects with high normal TSH concentration.

A dedicated cardioversion unit for the treatment of atrial fibrillation. Reducing costs by optimizing processes

BACKGROUND

Atrial fibrillation (AF) is the most frequent arrhythmia seen in man. Many patients are admitted to the hospital to undergo transesophageal echocardiography (TEE) for thrombus exclusion and subsequent electrical cardioversion (ECV) under deep sedation to restore sinus rhythm. The present study investigated prospectively how workflow optimization can contribute to reducing time and costs in AF patients scheduled for ECV in an outpatient setting.

METHODS

A cardioversion unit (CU) was established and equipped to perform all ECV-associated procedures. Between November 2007 and January 2009, ECV was performed in 115 patients in an outpatient setting. Three different settings were tested for ECV: (1) usual care (n = 19): preparation/follow-up in the outpatient clinic, blood testing in the central hospital laboratory (CHL), TEE in the echocardiography laboratory, and ECV in the intensive care unit; (2) optimized process 1 (n = 41): preparation/follow-up, TEE + ECV during one sedation in the CU, blood testing in the CHL; (3) optimized process 2 (n = 55): preparation/follow-up, TEE + ECV and point of care (POC) blood testing in the CU. All procedure-related costs were listed and classified according to material, human resources, and infrastructure.

RESULTS

From setting 1 to 3, there was a significant decrease in procedural time from 480 ± 105 min to 205 ± 85 min (p < 0.001). Likewise, ECV-associated costs could be reduced from 683 ± 104 <euro> to 299 ± 63 <euro> (p < 0.001).

CONCLUSION

Establishing a CU for AF enables a more than 50% reduction in procedural time and costs. A combination of TEE and ECV in one sedation and POC testing in the CU were the major contributors to this time and cost reduction.

Dabigatran in atrial fibrillation: pharmacology and clinical trials

The central pharmacologic approach to stroke prevention in atrial fibrillation has recently changed with the approval of dabigatran by the US Food and Drug Administration (FDA). Dabigatran is an oral anticoagulant that belongs to the class of direct thrombin inhibitors. Dabigatran has predictable pharmacokinetics, without significant drug and food interactions, rapid onset, and requires twice-daily administration without the need for monitoring. The only drug contraindicated with dabigatran is rifampin. In the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial, dabigatran at a dose of 150 mg bid is statistically superior to warfarin in preventing strokes and systemic embolism in patients with atrial fibrillation and has a lower non-statistically significant rate of major bleeding. There is significantly lower rate of intracranial bleeding. The FDA recently approved the 150-mg bid dose for patients with a creatinine clearance above 30 mL/min and 75 mg bid for use in patients with a creatinine clearance of 15 to 30 mL/min. A prespecified subanalysis in both warfarin-experienced and warfarin-naive subgroups mirrored the main results. For cardioversions, a post hoc analysis showed that the rate of thromboembolism and major bleeding within 30 days of cardioversion for dabigatran 150 mg bid was low and comparable to that of warfarin, with or without transesophageal echocardiography guidance. Dabigatran, therefore, is the first novel anticoagulant to offer an alternative to warfarin.

Role of echocardiography in atrial fibrillation

Atrial fibrillation (AF) is most common arrhythmia and its prevalence appears to be increasing as the population ages. Echocardiography can play a key role in risk stratification and management of patients with AF. Transthoracic echocardiography allows rapid and comprehensive assessment of cardiac anatomical structure and function. Pulmonary vein flow monitoring using echocardiography has the potential to an increasing role in the evaluation of cardiac function and AF ablation procedures. Transesophageal echocardiography also provides accurate information about the presence of a thrombus in the atria and thromboembolic risk. The novel technique of intracardiac echocardiography has emerged as a popular and useful tool in the everyday practice of interventional electrophysiology. Other imaging modalities, such as computed tomography and magnetic resonance imaging have complementary roles in risk stratification and assessment of patients with AF. Echocardiography continues to be the foundation of clinical evaluation and management of AF.

Platelet factor XIII gene expression and embolic propensity in atrial fibrillation

Nearly 15% of patients with non-valvular atrial fibrillation (NVAF) have left atrial appendage thrombus (LAAT) by transesophageal echocardiography (TEE) and yet the annual stroke rate averages 5%. The aim of this study was to identify variables influencing embolic propensity of LAAT. Platelet RNA was extracted from platelet-rich regions within formalin-fixed, paraffin-embedded specimens obtained from NVAF patients during cardiac surgery (26 LAAT from 23 patients) or peripheral embolectomy (51 thrombi from 41 patients). Platelet RNA was also assessed from whole blood from 40 NVAF patients. Expression of six platelet-predominate genes: H2A histone family, A1 domain of factor XIII, integrin α₂bβ₃; glycoprotein IX, platelet factor 4, glycoprotein Ib, was performed using TaqMan MGB-probe based quantitative real-time polymerase chain reaction. Platelet factor XIII subunit A gene expression was significantly lower in embolised compared to non-embolised thrombi as determined by normalised cycle threshold values (4.0 ± 1.2 v 2.8 ± 1.8, p=0.02). Expression of other genes did not differ by embolic status. In conclusion, RNA extracted from formalin-fixed, paraffin-embedded platelet-rich tissues can be used for analysis of platelet-predominate gene expression. Variable factor XIII gene expression in thrombi generated during NVAF may in part explain the propensity to embolisation.

Thyroid hormone, amiodarone therapy, and prognosis in left ventricular systolic dysfunction

BACKGROUND

Amiodarone protects patients with left ventricular systolic dysfunction (LVSD) against serious arrhythmias, but it also has numerous side effects on non-cardiac organs, such as the thyroid. Indeed, amiodarone may inhibit the peripheral conversion of T₄ into T₃. Pathologically reduced serum levels of T₃ - the so-called "low T₃ syndrome" (LOWT3) - increase mortality in patients with LVSD and not on amiodarone.

AIM

The aim of the study was to examine the relationship between thyroid hormone status, amiodarone therapy, and outcome in a population with LVSD. MATERIAL/ SUBJECTS AND METHODS: A total of 2344 patients with LVSD and free of overt hyper- and hypothyroidism were enrolled. The population was divided into 4 groups: group 1 (LOWT3 and amiodarone therapy, no.=126), group 2 (isolated amiodarone therapy, no.=74), group 3 (isolated LOWT3, no.=682), group 4 (controls, no.=1462).

RESULTS

Kaplan-Meier curves showed, after a mean follow-up of 31 months, increased total and cardiac mortality in groups 1 (30% and 20%, respectively), 2 (23%, 11%), and 3 (22%, 12%) compared to group 4 (total mortality log-rank 82.8, p<0.0001; cardiac mortality log-rank 63.1, p<0.0001). At Cox analysis, adjusted for several clinical variables, survival was reduced in groups 1 and 3 compared to group 4. Group 2 had a similar mortality to group 4, although the number of patients was too limited to accurately assess the effect of amiodarone on long-term prognosis.

CONCLUSIONS

LOWT3 exerts an adverse impact on prognosis in LVSD, which is not influenced by concomitant amiodarone therapy.

Specific antioxidant selenoproteins are induced in the heart during hypertrophy

Selenium (Se) is thought to confer cardioprotective effects through the actions of antioxidant selenoprotein enzymes that directly limit levels of ROS such as hydrogen peroxide (H(2)O(2)) or that reverse oxidative damage to lipids and proteins. To determine how the selenoproteome responds to myocardial hypertrophy, two mouse models were employed: triidothyronine (T3)- or isoproterenol (ISO)-treatment. After 7days of T3- and ISO-treatment, cardiac stress was demonstrated by increased H(2)O(2) and caspase-3 activity. Neither treatment produced significant increases in phospholipid peroxidation or TUNEL-positive cells, suggesting that antioxidant systems were protecting the cardiomyocytes from damage. Many selenoprotein mRNAs were induced by T3- and ISO-treatment, with levels of methionine sulfoxide reductase 1 (MsrB1, also called SelR) mRNA showing the largest increases. MsrB enzymatic activity was also elevated in both models of cardiac stress, while glutathione peroxidase (GPx) activity and thioredoxin reductase (Trxrd) activity were moderately and nonsignificantly increased, respectively. Western blot assays revealed a marked increase in MsrB1 and moderate increases in GPx3, GPx4, and Trxrd1, particularly in T3-treated hearts. Thus, the main response of the selenoproteome during hypertrophy does not involve increased GPx1, but increased GPx3 for reducing extracellular H(2)O(2) and increased GPx4, Trxrd1, and MsrB1 for minimizing intracellular oxidative damage.

Decreased number of circulating endothelial progenitor cells in patients with Graves' hyperthyroidism

OBJECTIVE

A relevant biological role of circulating endothelial progenitor cells (EPC) was recently demonstrated. EPC are generated in the bone marrow, and interact with damaged endothelium, restoring the integrity of the monolayer. Therefore, aim of the present study was to evaluate EPC in the blood of patients with untreated Graves' hyperthyroidism (GD), in whom an increased oxidative stress was observed.

DESIGN AND METHODS

Twenty-three patients with untreated active GD and 18 matched normal controls (NC) were included in the study. Circulating EPC were isolated from peripheral blood. Mononuclear cells were cultured with endothelial basal medium supplemented with EGM SingleQuots, and were identified by positive double staining after 7 days in culture. Circulating levels of C reactive protein, total antioxidant power, interleukin (IL)-6, IL- 18, monocyte chemoattractant protein-1, tumor necrosis facotr- α, soluble vascular cell adhesion molecule (VCAM) and intracellular adhesion molecule were evaluated by enzymelinked immunosorbent assay kit. EPC number was also evaluated in a subgroup of GD patients after restoration of euthyroidism.

RESULTS

Systolic blood pressure resulted increased in GD patients compared with control subjects whereas diastolic blood pressure was not significantly different. Patients with GD showed an increase in circulating levels of IL-18 and VCAM-1 and a reduction of total antioxidant power (p<0.05) compared to NC. Moreover, a reduced number of EPC was observed in patients with GD compared to NC (p<0.05) which turned to NC values after restoring euthyroidism.

CONCLUSION

Patients with GD showed a reduction in the physiological protective mechanisms against endothelial damage, probably induced by increased inflammation and oxidative stress.

Canadian Cardiovascular Society atrial fibrillation guidelines 2010: prevention of stroke and systemic thromboembolism in atrial fibrillation and flutter

The stroke rate in atrial fibrillation is 4.5% per year, with death or permanent disability in over half. The risk of stroke varies from under 1% to over 20% per year, related to the risk factors of congestive heart failure, hypertension, age, diabetes, and prior stroke or transient ischemic attack (TIA). Major bleeding with vitamin K antagonists varies from about 1% to over 12% per year and is related to a number of risk factors. The CHADS(2) index and the HAS-BLED score are useful schemata for the prediction of stroke and bleeding risks. Vitamin K antagonists reduce the risk of stroke by 64%, aspirin reduces it by 19%, and vitamin K antagonists reduce the risk of stroke by 39% when directly compared with aspirin. Dabigatran is superior to warfarin for stroke prevention and causes no increase in major bleeding. We recommend that all patients with atrial fibrillation or atrial flutter, whether paroxysmal, persistent, or permanent, should be stratified for the risk of stroke and for the risk of bleeding and that most should receive antithrombotic therapy. We make detailed recommendations as to the preferred agents in various types of patients and for the management of antithrombotic therapies in the common clinical settings of cardioversion, concomitant coronary artery disease, surgical or diagnostic procedures with a risk of major bleeding, and the occurrence of stroke or major bleeding. Alternatives to antithrombotic therapies are briefly discussed.

Low molecular weight heparin (parnaparin) for cardioembolic events prevention in patients with atrial fibrillation undergoing elective electrical cardioversion: a prospective cohort study

Systemic thromboembolism is a severe complication in patients undergoing electrical cardioversion (ECV) for atrial fibrillation (AF). Vitamin K antagonists greatly reduce the risk of thromboembolic events, but the administration scheme before ECV is troublesome as difficulties in reaching and maintaining the target therapeutic range for 3 weeks often delay the restoration and likelihood of maintaining sinus rhythm. Low molecular weight heparins (LMWHs) do not need dose adjustment, and may be preferable in this clinical setting. In this multicentre study, the LMWH parnaparin was used at a dose of 85 anti-factor Xa U/kg b.i.d. 2 weeks before and 3 weeks after ECV of AF. In an intention to treat analysis of 102 patients, there was no systemic thromboembolism or major bleeding (0%, 95% CI 0-3.6). Two clinically relevant non-major bleeds (2.5%, 95% CI 0.7-8.8) and three minor bleeds (3.8%, 95% CI 1.3-10.6) were recorded. No heparin-induced thrombocytopenia or other major adverse events were recorded. Parnaparin appears effective and safe for thromboprophylaxis of elective ECV in patients with AF.

Echocardiographic predictors of left atrial appendage thrombus formation

BACKGROUND

Although transesophageal echocardiography is the definitive test for the detection of left atrial (LA) appendage thrombus, transthoracic echocardiography has yet to prove useful for the determination of increased risk for LA appendage thrombus formation. The authors hypothesized that higher LA volume and/or lower left ventricular ejection fraction (LVEF) might prove valuable as markers of increased risk for LA appendage thrombus formation and tested this hypothesis in a consecutive retrospective series of patients with atrial fibrillation undergoing both transthoracic and transesophageal echocardiography.

METHODS

Three hundred thirty-four consecutive patients with atrial fibrillation undergoing transesophageal echocardiography for the detection of LA appendage thrombus were studied. Anticoagulation status, CHADS(2) scores, and echocardiographic parameters were catalogued. The relationship between the presence of LA appendage thrombus and covariates was analyzed using binary logistic regression.

RESULTS

LA appendage thrombus was detected in 52 patients (15.6%). A higher CHADS(2) score (odds ratio, 1.45; P < .004), increased LA volume index (odds ratio, 1.02; P = .018), and lower LVEF (odds ratio, 1.02; P = .05) were significant predictors of LA appendage thrombus formation. LA appendage thrombus was not seen in patients with CHADS(2) scores ≤ 1, LVEFs > 55%, and a LA volume indexes < 28 mL/m(2). A ratio of LVEF to LA volume index ≤ 1.5 produced 100% sensitivity for the presence of LA appendage thrombus.

CONCLUSIONS

The presence of LA appendage thrombus is related to both clinical and echocardiographic variables. Although no single echocardiographic variable discriminated between the presence and absence of LA thrombus, a normal LVEF and normal LA volume index were associated with the absence of LA appendage thrombus formation. For patients with atrial fibrillation with CHADS(2) scores ≤ 1, normal left ventricular systolic function and normal LA volume in combination may be a useful measure for the identification of patients at low risk for LA appendage thrombus formation.