Management of patients with atrial fibrillation. A Statement for Healthcare Professionals. From the Subcommittee on Electrocardiography and Electrophysiology, American Heart Association

Diastolic Dysfunction and Atrial Fibrillation: Recognition, Interplay, and Management

Diastolic dysfunction occurs when the left ventricle loses its ability to relax normally, impairing ventricular filling during diastole. This most commonly occurs as a pathological sequela of left ventricular hypertrophy and remodeling due to chronic hypertension and/or age-related sclerotic changes of the aortic valve. This can subsequently deteriorate to diastolic heart failure or heart failure with preserved ejection fraction. There is a substantive interplay between atrial fibrillation and diastolic dysfunction, as atrial fibrillation can cause, exacerbate, or be a direct result of diastolic dysfunction and vice versa. In this review, we first independently define diastolic heart failure and atrial fibrillation while discussing the diagnostic guidelines, which encompass various modalities such as medical history, electrocardiography, echocardiography, and laboratory tests. We subsequently examine their interplay and pathophysiological links drawing on recent evidence in the literature. Finally, we discuss management approaches, including pharmacological interventions targeting rate and rhythm control, diuretics, and addressing comorbidities.

Association between the atrial tachyarrhythmia recurrence period and long-term major adverse clinical events following catheter ablation for atrial fibrillation

Background

We previously demonstrated the clinical events in patients who underwent catheter ablation (CA) for atrial fibrillation (AF). Data on the association between the period of atrial tachyarrhythmia (ATA) recurrence after CA and long-term major adverse clinical events (MACE) remain unclear. In this study, we evaluated this issue in patients with systolic impairment (left ventricular ejection fraction < 50%) and heart failure with preserved ejection fraction (HFpEF).

Methods

We retrospectively collected data from 81 patients with systolic impairment and 83 patients with HFpEF who underwent CA for AF at our institution (median follow-up: 4.9 [3.6, 6.6] years). In each group, we compared the cumulative incidence of long-term MACE (since 1 year after CA) between patients with and without ATA recurrence at three follow-up periods (3, 6 months, and 1 year after index CA). We evaluated the period of recurrence, which was the most beneficial predictor of MACE among the periods.

Results

In the systolic impairment group, the cumulative long-term MACE incidence was significantly higher in patients with ATA recurrence than in those without it within 6 months and 1 year (P = 0.04 and P = 0.01, respectively). Recurrence within 1 year showed the highest feasibility for predicting long-term MACE (area under the curve with 95% confidence interval [CI]:0.73 [0.61-0.84]). However, there was no difference in the incidence of MACE between patients with and without recurrence in a group with HFpEF in each period.

Conclusion

ATA recurrence within 1 year could predict long-term MACE in patients with systolic impairment, but not in patients with HFpEF.

Risk factors associated with left atrial appendage thrombosis in patients with non-valvular atrial fibrillation by transesophageal echocardiography

PURPOSE

This study investigated possible mechanism of left atrial appendage (LAA) thrombosis and constructed a model to evaluate the future risk of LAA thrombosis and spontaneous echo contrast (SEC) in non-valvular atrial fibrillation (NVAF) patients.

METHODS

This retrospective study included 2591 patients diagnosed with NVAF. Patients were divided based on the presence of transesophageal echocardiography (TEE) into a thrombus group, SEC group, and control group. General, biochemical, and echocardiography data of the three groups were analyzed. The variables independently associated with LAA thrombosis and SEC were determined by the logistic regression analysis. A nomogram was constituted based on the regression analysis and the discriminatory ability was analyzed by receiver operating characteristic (ROC) curve.

RESULTS

LAA thrombosis and SEC were present in 110 (4.2%) patients and 103 (3.9%) patients, respectively. AF type (OR = 1.857), previous stroke (OR = 1.924), fibrinogen (OR = 1.636), diameters of the left atria (OR = 1.094), left ventricular ejection fraction (OR = 0.938), and LAA maximum caliber (OR = 1.238) resulted as independent risk factors for LAA thrombosis and SEC. The area under curve of the nomogram established by multivariate logistic regression was 0.824. Conclusions; Through the study, 6 independent risk factors related to the LAA thrombosis and SEC were found, and an effective nomogram was constructed to predict the LAA thrombosis and SEC in NVAF patients.

Efficacy of intravenous magnesium for the management of non-post operative atrial fibrillation with rapid ventricular response: A systematic review and meta-analysis

BACKGROUND

Intravenous magnesium (IV Mg), a commonly utilized therapeutic agent in the management of atrial fibrillation (AF) with rapid ventricular response, is thought to exert its influence via its effect on cellular automaticity and prolongation of atrial and atrioventricular nodal refractoriness thus reducing ventricular rate. We sought to undertake a systematic review and meta-analysis of the effectiveness of IV Mg versus placebo in addition to standard pharmacotherapy in the rate and rhythm control of AF in the nonpostoperative patient cohort given that randomized control trials (RCTs) have shown conflicting results.

METHODS

Randomized controlled trials comparing IV Mg versus placebo in addition to standard of care were identified via electronic database searches. Nine RCTs were returned with a total of 1048 patients. Primary efficacy endpoints were study-defined rate control and rhythm control/reversion to sinus rhythm. The secondary endpoint was patient experienced side effects.

RESULTS

Our analysis found IV Mg in addition to standard care was successful in achieving rate control (odd ratio [OR] 1.87, 95% confidence interval [CI] 1.13-3.11, p = .02) and rhythm control (OR 1.45, 95% CI 1.04-2.03, p = .03). Although not well reported among studies, there was no significant difference between groups regarding the likelihood of experiencing side effects.

CONCLUSIONS

IV Mg, in addition to standard-of-care pharmacotherapy, increases the rates of successful rate and rhythm control in nonpostoperative patients with AF with rapid ventricular response and is well tolerated.

A multicenter prospective randomized study comparing the incidence of periprocedural cerebral embolisms caused by catheter ablation of atrial fibrillation between cryoballoon and radiofrequency ablation (Embo-Abl study): Study design

BACKGROUND

Although catheter ablation (CA) has become a standard therapeutic approach to atrial fibrillation (AF), it imposes a low but relevant risk of thromboembolic complications of around 0.5%-1%, including ischemic strokes, and has an additional risk of clinically silent cerebral embolisms (SCEs) of 10%-40%. Both cryoballoon (CB) and radiofrequency (RF) ablation are routinely used clinically worldwide, yet there are few prospective data comparing the incidence of cerebral embolism after CA of AF between CB and RF ablation.

METHODS

The aim of the Embo-Abl study will be to compare the incidence of cerebral embolisms on 3 T diffusion-weighted image magnetic resonance imaging (MRI) after CA of AF between CB and RF ablation in patients with AF in a prospective, multicenter, open-label, controlled, randomized fashion. The primary endpoint of the Embo-Abl study will be the occurrence of MRI-detected SCE 1-3 days after CA. The patients will be registered and randomly assigned to either the CB or RF ablation group in a 1:1 ratio. The study cohort will include 230 patients with AF from a multicenter in Japan.

RESULTS

The results of this study are currently under investigation.

CONCLUSION

The Embo-Abl study will be the first to compare the incidence of periprocedural cerebral embolisms caused by CA of AF between CB and RF ablation in a prospective, multicenter, randomized, controlled fashion.

Transcriptomics-based network medicine approach identifies metformin as a repurposable drug for atrial fibrillation

Effective drugs for atrial fibrillation (AF) are lacking, resulting in significant morbidity and mortality. This study demonstrates that network proximity analysis of differentially expressed genes from atrial tissue to drug targets can help prioritize repurposed drugs for AF. Using enrichment analysis of drug-gene signatures and functional testing in human inducible pluripotent stem cell (iPSC)-derived atrial-like cardiomyocytes, we identify metformin as a top repurposed drug candidate for AF. Using the active compactor, a new design analysis of large-scale longitudinal electronic health record (EHR) data, we determine that metformin use is significantly associated with a reduced risk of AF (odds ratio = 0.48, 95%, confidence interval [CI] 0.36-0.64, p < 0.001) compared with standard treatments for diabetes. This study utilizes network medicine methodologies to identify repurposed drugs for AF treatment and identifies metformin as a candidate drug.

PrismatoidPatNet54: An Accurate ECG Signal Classification Model Using Prismatoid Pattern-Based Learning Architecture

Background and objective: Arrhythmia is a widely seen cardiologic ailment worldwide, and is diagnosed using electrocardiogram (ECG) signals. The ECG signals can be translated manually by human experts, but can also be scheduled to be carried out automatically by some agents. To easily diagnose arrhythmia, an intelligent assistant can be used. Machine learning-based automatic arrhythmia detection models have been proposed to create an intelligent assistant. Materials and Methods: In this work, we have used an ECG dataset. This dataset contains 1000 ECG signals with 17 categories. A new hand-modeled learning network is developed on this dataset, and this model uses a 3D shape (prismatoid) to create textural features. Moreover, a tunable Q wavelet transform with low oscillatory parameters and a statistical feature extractor has been applied to extract features at both low and high levels. The suggested prismatoid pattern and statistical feature extractor create features from 53 sub-bands. A neighborhood component analysis has been used to choose the most discriminative features. Two classifiers, k nearest neighbor (kNN) and support vector machine (SVM), were used to classify the selected top features with 10-fold cross-validation. Results: The calculated best accuracy rate of the proposed model is equal to 97.30% using the SVM classifier. Conclusion: The computed results clearly indicate the success of the proposed prismatoid pattern-based model.

Clinical utility of cardiac magnetic resonance imaging to assess the left atrium before catheter ablation for atrial fibrillation - A systematic review and meta-analysis

AIMS

This systematic review and meta-analysis aims to clarify the role of pre-procedural cardiac magnetic resonance imaging (MRI) in identifying the association between left atrial (LA) characteristics and post-ablation atrial fibrillation (AF) recurrence. These characteristics include LA fibrosis, emptying function, sphericity, volume, volume index, peak strain and post-contrast T1 relaxation time.

METHODS

PubMed, EMBASE, and Cochrane were searched up to July 2020 for English language articles reporting the use of cardiac MRI in catheter ablation for AF. Studies reporting the prognostic value of pre-ablation cardiac MRI were included. All references and citations were filtered for relevant manuscripts.

RESULTS

Twenty-four publications were identified. Every 10% increase in LA fibrosis was associated with a 1.54-fold increase in post-ablation AF recurrence (95%CI: 1.39-1.70, I² = 50.1%). Every 10 ml increase in LA volume resulted in a hazard ratio of 1.07 (95%CI:1.03-1.12; I² = 41.4%) for post-ablation AF recurrence. For LA sphericity, there was no significant association with post-ablation AF recurrence (HR: 1.032 [95%CI: 0.962-1.103, I² = 49.6%). Egger's test was non-significant for publication bias in all meta-analyses. LA volume index, emptying function, peak strain and post-contrast LA T1 relaxation time had insufficient compatible publications to conduct a meta-analysis.

CONCLUSION

LA fibrosis quantified by cardiac MRI is associated with risk of AF recurrence after AF ablation, while increased LA volume is associated with AF recurrence to a lesser extent. There remains insufficient evidence to support the routine measurement of LA sphericity, LA volume index, LA emptying function, peak strain and LA T1 relaxation time to predict AF recurrence after AF ablation.

Comparison of the efficacy and safety of different doses of nifekalant in the instant cardioversion of persistent atrial fibrillation during radiofrequency ablation

Nifekalant has been used in the treatment of atrial arrhythmia recently. However, there is no consensus on the preferable nifekalant dose to treat atrial fibrillation (AF). The purpose of this study was to explore efficacy and safety of different doses of nifekalant in the cardioversion of persistent AF. The study was a single-centre, randomized controlled trial. All subjects received nifekalant or placebo intravenously, and the nifekalant was given at the dosage of 0.3, 0.4 or 0.5 mg/kg. Primary efficacy end-point: compared with 0.3 mg group, the rate of cardioversion to sinus rhythm from AF in 0.4 and 0.5 mg group was higher. The 0.4 and 0.5 mg/kg doses were associated with a similar magnitude of efficacy (P > .05). Secondary efficacy end-point: termination rates of AF in the group of 0.4 mg and 0.5 mg were higher than 0.3 mg. Primary safety end-point: the rate of Torsades de Pointes or ventricular fibrillation was numerically lower in the 0.4 mg group than 0.5 mg group (P = .02). Secondary safety end-point: The rates of the majority of other common drug-related adverse events in the group of 0.5 and 0.4 mg were higher than the 0.3 mg group. A 0.4 mg/kg dose of intravenous nifekalant may be recommended during the radiofrequency ablation for persistent AF considering the benefit-risk profile.

Gastroesophageal Reflux and Its Association With Atrial Fibrillation: A Traditional Review

Atrial fibrillation (AF) is a common arrhythmia, and gastroesophageal reflux disease (GERD) is a common gastroenterology disease; both are highly encountered daily in clinical practice. Since both share common predisposing factors, we can conclude that there is a link between them. To date, the precise mechanism of reflux disease as a possible cause of atrial fibrillation remains uncertain. However, some possibilities can be postulated, such as the inflammation process, and sympathovagal imbalance represents the main factors for how GERD can initiate AF. Vigorous aerobic exercise in healthy people can bring about acidic esophageal reflux, which is a common risk factor for AF. Various inflammatory markers such as C-reaction protein (CRP) and interleukins have been a central role in initiating AF. A large hiatal hernia (HH) can cause direct compression on the left atrium that is possibly predisposing to atrial arrhythmogenesis. It has been sporadically reported that using a proton pump inhibitor to treat GERD in patients with coexisting AF has a noticeable effect on decreasing symptoms of AF and recurrence with less cost and side effects.

Cryoballoon catheter ablation versus antiarrhythmic drugs as a first-line therapy for patients with paroxysmal atrial fibrillation: Rationale and design of the international Cryo-FIRST study

BACKGROUND

Radiofrequency current (RFC) catheter ablation for patients with paroxysmal atrial fibrillation (AF) has been shown to be safe and effective in first-line therapy. Recent data demonstrates that RFC ablation provides better clinical outcomes compared to antiarrhythmic drug (AAD) in the treatment of early AF disease. Furthermore, studies comparing RFC and cryoballoon have established comparable efficacy and safety of pulmonary vein isolation (PVI) for patients with symptomatic paroxysmal AF.

OBJECTIVES

The Cryo-FIRST trial was designed to compare AAD treatment against cryoballoon PVI as a first-line therapy in treatment naïve patients with AF. Efficacy and safety will be compared between the two cohorts and amongst subgroups.

METHODS

The primary hypothesis is that cryoablation is superior to AAD therapy. To test this hypothesis, patients will be randomized in a 1:1 design. Using a 90-day blanking period, primary efficacy endpoint failure is defined as (at least) one episode of atrial arrhythmia with a duration >30 sec (documented by 7-day Holter or 12-lead ECG). Secondary endpoints (Quality-of-Life, rehospitalization, arrhythmia recurrence rate, healthcare utilization, and left atrial function) and adverse events will also be evaluated. Study enrollment will include 218 patients in up to 16 centers.

CONCLUSIONS

This study will be a multi-national randomized controlled trial comparing cryoablation against AAD as a first-line treatment in patients with paroxysmal AF. The results may help guide the selection of patients for early AF disease therapy via cryoballoon ablation.

Atrial Infarction-Induced Spontaneous Focal Discharges and Atrial Fibrillation in Sheep: Role of Dantrolene-Sensitive Aberrant Ryanodine Receptor Calcium Release

BACKGROUND

The mechanisms underlying spontaneous atrial fibrillation (AF) associated with atrial ischemia/infarction are incompletely elucidated. Here, we investigate the mechanisms underlying spontaneous AF in an ovine model of left atrial myocardial infarction (LAMI).

METHODS AND RESULTS

LAMI was created by ligating the atrial branch of the left anterior descending coronary artery. ECG loop recorders were implanted to monitor AF episodes. In 7 sheep, dantrolene-a ryanodine receptor blocker-was administered in vivo during the 8-day observation period (LAMI-D, 2.5 mg/kg, IV, BID). LAMI animals experienced numerous spontaneous AF episodes during the 8-day monitoring period that were suppressed by dantrolene (LAMI, 26.1±5.1; sham, 4.3±1.1; LAMI-D, 2.8±0.8; mean±SEM episodes per sheep, P<0.01). Optical mapping showed spontaneous focal discharges (SFDs) originating from the ischemic/normal-zone border. SFDs were calcium driven, rate dependent, and enhanced by isoproterenol (0.03 µmol/L, from 210±87 to 3816±1450, SFDs per sheep) but suppressed by dantrolene (to 55.8±32.8, SFDs per sheep, mean±SEM). SFDs initiated AF-maintaining reentrant rotors anchored by marked conduction delays at the ischemic/normal-zone border. NOS1 (NO synthase-1) protein expression decreased in ischemic zone myocytes, whereas NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) oxidase and xanthine oxidase enzyme activities and reactive oxygen species (DCF [6-carboxy-2',7'-dichlorodihydrofluorescein diacetate]-fluorescence) increased. CaM (calmodulin) aberrantly increased [³H]ryanodine binding to cardiac RyR2 (ryanodine receptors) in the ischemic zone. Dantrolene restored the physiological binding of CaM to RyR2.

CONCLUSIONS

Atrial ischemia causes spontaneous AF episodes in sheep, caused by SFDs that initiate reentry. Nitroso-redox imbalance in the ischemic zone is associated with intense reactive oxygen species production and altered RyR2 responses to CaM. Dantrolene administration normalizes the CaM response, prevents LAMI-related SFDs, and AF initiation. These findings provide novel insights into the mechanisms underlying ischemia-related atrial arrhythmias.

Beta-blockers use from the general to the hemodialysis population

Beta-blockers have numerous indications in the general population and are strongly recommended in heart failure, post-myocardial infarction and arrhythmias. In hemodialysis patients, their use is based on weak evidence because of the lack of a sufficient number of randomized clinical trials. The strongest evidence is based on two trials. The first showed better survival with carvedilol in hemodialysis patients with four sessions per week and systolic heart failure. The second found reduced cardiovascular morbidity with atenolol compared to lisinopril in mostly black hypertensive hemodialysis patients. No clinical trials exist regarding myocardial infarction. Large retrospective studies have assessed the benefits of beta-blockers in hemodialysis. A large cohort of hemodialysis patients with new-onset heart failure showed better survival when treated with carvedilol, bisoprolol or metoprolol. Another recent one of 20,064 patients found out that metoprolol compared to carvedilol was associated with less all-cause mortality. There is still uncertainty also regarding the impact of dialysability of beta-blockers on patient's survival. On top of that, many observations suggested that beta-blockers were associated with a reduced rate of sudden cardiac death in hemodialysis patients but recent data show a link between bradycardia and sudden cardiac death questioning the benefit of beta-blockade in this population. Finally, what we know for sure so far is that beta-blockers should be avoided in patients with intradialytic hypotension associated with bradycardia.

Sympathetic Nervous System Activation and Its Modulation: Role in Atrial Fibrillation

The autonomic nervous system (ANS) has a significant influence on the structural integrity and electrical conductivity of the atria. Aberrant activation of the sympathetic nervous system can induce heterogeneous changes with arrhythmogenic potential which can result in atrial tachycardia, atrial tachyarrhythmias and atrial fibrillation (AF). Methods to modulate autonomic activity primarily through reduction of sympathetic outflow reduce the incidence of spontaneous or induced atrial arrhythmias in animal models and humans, suggestive of the potential application of such strategies in the management of AF. In this review we focus on the relationship between the ANS, sympathetic overdrive and the pathophysiology of AF, and the potential of sympathetic neuromodulation in the management of AF. We conclude that sympathetic activity plays an important role in the initiation and maintenance of AF, and modulating ANS function is an important therapeutic approach to improve the management of AF in selected categories of patients. Potential therapeutic applications include pharmacological inhibition with central and peripheral sympatholytic agents and various device based approaches. While the role of the sympathetic nervous system has long been recognized, new developments in science and technology in this field promise exciting prospects for the future.

Left atrial function: evaluation by strain analysis

The left atrium has an important role in modulating left ventricular filling and is an important biomarker of cardiovascular disease and adverse cardiovascular outcomes. While previously left atrial (LA) size was utilised, the role of LA function as a biomarker is increasingly being evaluated, both independently and also in combination with LA size. Strain analysis has been utilised for evaluation of LA function and can be measured throughout the cardiac cycle, thereby enabling the evaluation of LA reservoir, conduit and contractile function. Strain evaluates myocardial deformation while strain rate examines the rate of change in strain. This review will focus on the various types of strain analysis for evaluation of LA function, alterations in LA strain in physiological and pathologic states that alter LA function and finally evaluate its utility as a prognostic marker.

A survey of reasons for continuing warfarin therapy in the era of direct oral anticoagulants in Japanese patients with atrial fibrillation: the SELECT study

PURPOSE

Although warfarin has historically been the standard of care for preventing ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF), the use of direct oral anticoagulants (DOACs) is rapidly increasing. In this study, we examined the demographic and clinical characteristics of patients continuing warfarin therapy and investigated reasons for warfarin continuation.

PATIENTS AND METHODS

Each study site consecutively registered 10 patients with NVAF who had been taking warfarin for at least 12 months. Demographic and clinical characteristics and international normalized ratio (INR) values were collected from medical records. Physicians responded to questionnaires exploring reasons for continuing warfarin therapy.

RESULTS

Overall, 313 patients treated with warfarin were registered at 33 sites. Mean ± SD age was 76.4±9.6 years; 62.9% of patients were male. The proportion of patients with INR values in the therapeutic range was 74.6% and 48.8% among patients aged ≥70 years and <70 years, respectively. Over half of the patients (51.4%) had been advised to switch from warfarin to DOACs; the primary physician-reported reason for this recommendation was superior safety and effectiveness. However, patients reported continuing warfarin because of the high price of DOACs (47.2%) and long-term positive experiences with warfarin (31.7%). The remaining 48.6% of patients with NVAF had never been counseled by their physicians about DOACs as an alternative to warfarin. For 76% of these patients, physicians favored warfarin for medical reasons, such as impaired renal function and controlled INR, but in the remaining patients, medical reasons for continuing warfarin were lacking.

CONCLUSION

Approximately half of the patients in this study were informed of warfarin alternatives primarily for improved efficacy and safety, but elected not to change regimens because of the high price of DOACs and long-term positive experiences with warfarin. In the remaining half, physician preference or specific patient characteristics prevented a change in therapy.

Bleeding risk of apixaban, dabigatran, and low-dose rivaroxaban compared with warfarin in Japanese patients with non-valvular atrial fibrillation: a propensity matched analysis of administrative claims data

OBJECTIVES

There is scarce evidence comparing novel oral anticoagulants (NOACs) with warfarin in real-world settings in Japan. This study compared the risk of bleeding events among patients with non-valvular atrial fibrillation (NVAF) initiating treatment with NOACs versus warfarin.

METHODS

A retrospective cohort study was conducted using a de-identified electronic health record based database of health claims and Diagnosis Procedure Combination data from 275 consenting hospitals in Japan. NVAF patients newly initiated on oral anticoagulants were eligible. Based on the first prescription, patients were assigned to 5/2.5 mg BID apixaban, 150/110 mg BID dabigatran, 15/10 mg QD rivaroxaban (approved dose lower in Japan compared to Western countries [20/15 mg QD]) or warfarin groups. One-to-one propensity score matching (PSM) was used to balance patient characteristics between warfarin and each NOAC. Patients were followed up to 1 year post-first prescription.

RESULTS

Among 38,662 eligible patients, a total of 5977, 5090, and 6726 matched pairs were identified for warfarin versus apixaban, warfarin versus dabigatran, and warfarin versus rivaroxaban, respectively after PSM. Compared to warfarin, apixaban (hazard ratio [HR] 0.586; 95% CI 0.421-0.815), dabigatran (HR 0.617; 0.425-0.895) and rivaroxaban (HR 0.693; 0.514-0.933) were associated with a significantly lower risk of major bleeding. The risk of any bleeding was significantly lower for apixaban (HR 0.782; 0.682-0.896), but not for dabigatran (HR 0.988; 0.860-1.135) or rivaroxaban (HR 0.938; 0.832-1.057) when comparing to warfarin.

CONCLUSIONS

Among Japanese patients with NVAF, treatment with apixaban 5/2.5 mg BID was associated with a significantly lower risk of major bleeding and any bleeding when compared to warfarin. Treatment with dabigatran 150/110 mg BID or rivaroxaban 15/10 mg QD was associated with a significantly lower risk of major bleeding, but not any bleeding, than warfarin. The potential benefit of individual NOACs in real-world practice needs to be assessed further.

Clinical characteristics and 12-month outcomes of patients with valvular and non-valvular atrial fibrillation in Kenya

BACKGROUND

Atrial fibrillation (AF) is a major contributor to the global cardiovascular disease burden. The clinical profile and outcomes of AF patients with valvular heart diseases in sub-Saharan Africa (SSA) have not been adequately described. We assessed clinical features and 12-month outcomes of patients with valvular AF (vAF) in comparison to AF patients without valvular heart disease (nvAF) in western Kenya.

METHODS

We performed a cohort study with retrospective data gathering to characterize risk factors and prospective data collection to characterize their hospitalization, stroke and mortality rates.

RESULTS

The AF patients included 77 with vAF and 69 with nvAF. The mean (SD) age of vAF and nvAF patients were 37.9(14.5) and 69.4(12.3) years, respectively. There were significant differences (p<0.001) between vAF and nvAF patients with respect to female sex (78% vs. 55%), rates of hypertension (29% vs. 73%) and heart failure (10% vs. 49%). vAF patients were more likely to be taking anticoagulation therapy compared to those with nvAF (97% vs. 76%; p<0.01). After 12-months of follow-up, the overall mortality, hospitalization and stroke rates for vAF patients were high, at 10%, 34% and 5% respectively, and were similar to the rates in the nvAF patients (15%, 36%, and 5%, respectively).

CONCLUSION

Despite younger age and few comorbid conditions, patients with vAF in this developing country setting are at high risk for nonfatal and fatal outcomes, and are in need of interventions to improve short and long-term outcomes.

Do All Patients with Atrial Fibrillation Need Long-Term Anticoagulation?

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide with an estimated number of 2.7-6.1 million cases in the United States (US) alone. The incidence of AF is expected to increase 2.5 fold over the next 50 years in the US. The management of AF is complex and includes mainly three aspects; restoration of sinus rhythm, control of ventricular rate and prevention of systemic thromboembolism. AF as a cause of systemic embolization has been well known for many years, and majority of patients are on oral anticoagulants (OACs) to prevent this. Many times, a patient may not be in AF chronically, nor is the AF burden (the amount of time patient is in AF out of the total monitored time) calculated. We present three cases of new onset transient AF triggered by temporary stressors. We were able to restore normal sinus rhythm (NSR) with chemical cardioversion. As per 2014 American College of Cardiology (ACC)/American Heart Association (AHA) recommendations, we started all three patients on OACs based on CHA₂DS₂VASc score ≥2. However, the patients refused long term OACs after restoration of NSR and correction of the temporary enticing stressors. In any case, the decision to start OACs would have had its own risks. Here we describe how antiarrhythmic drugs were used to maintain NSR, all while they were continuously monitored to determine the need to continue OACs.

Sinus Rhythm in Rheumatic Mitral Stenosis after Balloon Mitral Valvotomy: Is it Feasible?

INTRODUCTION

Atrial Fibrillation (AF) is largely present in patients with rheumatic valvular disease, leading to hospitalizations.

AIM

We aimed to study the restoration and maintenance of Sinus Rhythm (SR) in rheumatic patients with Mitral Stenosis (MS) and AF after Balloon Mitral Valvotomy (BMV) and evaluated the factors which affect the maintenance of SR.

MATERIALS AND METHODS

A total of 50 patients who underwent BMV at U. N. Mehta Institute of Cardiology and Research Centre from 2010 November to 2013 January were included in the study. Subsequently, all patients were treated with amiodarone and electrical cardioversion was applied in patients in whom it was necessary. The patients were followed for six months for conversion and maintenance of SR.

RESULTS

Total 34 (68%) patients reverted to SR. Twelve patients reverted to SR with amiodarone and 22 patients with electrical cardioversion and amiodarone. Out of the total, 29 patients and 26 patients remained in SR at the end of follow up at 3 months and 6 months respectively.

CONCLUSION

Smaller Left Atrial (LA) size and greater Mitral Valve Area (MVA) are the chief predictors of restoration and maintenance of SR. Combining BMV with an aggressive anti-arrhythmic strategy offers the best prospect of rhythm control.

Morphologic classification of the right auricule on 256-slice computed tomography

PURPOSE

To investigate the shape of right auricule on 256-slice computed tomography (CT).

MATERIALS AND METHODS

Five hundred people (250 men, age range 16-84 years) who had cardiac multidetector CT angiography were recruited in this study. All patients had normal sinus rhythm with normal blood pressure (<140/90 mmHg for systolic/diastolic pressure). The morphology of the right auricule was studied and compared after reconstruction of the raw images.

RESULTS

All patients successfully had cardiac CT angiography (100%), and the right auricule morphology was divided into five types and nine subtypes, including Type I of triangular shape (Ia and Ib), Type II of M shape (IIa and IIb), Type III of L shape (IIIa and IIIb), Type IV of reverse L shape (IVa and IVb), and Type V of balanced shape. The most common type of right auricule is Type IV (28.4%) followed by Type II (24.0%), whereas the least common is Type V (11.0%). Type Ia was present significantly (P < 0.0001) more frequently in females than in males, whereas Type IIa significantly (P = 0.042) more frequently in males than females. No other significant (P > 0.05) sex difference existed in the constitution ratio of the types. The normal angle was greater in Type Ib than in Ia. The greater the normal angle in Type I, the greater the deviation of the right auricule tip towards the left.

CONCLUSION

A good understanding of the right auricule anatomical morphology can better guide atrial pacing, radiofrequency ablation and other surgical procedures while preventing possible intra-procedural complications.

Associations of big endothelin-1 and C-reactive protein in atrial fibrillation

Background

Atrial fibrillation (AF) is associated with inflammation and endothelial dysfunction. However, the association between inflammation (as indexed by high-sensitivity C-reactive protein, hs-CRP) and endothelial function [as indexed by big endothelin-1 (ET-1)] in AF patients remains unclear.

Methods

We enrolled 128 patients with lone AF, among which 83 had paroxysmal AF, and 45 had persistent AF. Eighty-two age- and gender-matched controls of paroxysmal supraventricular tachycardia without AF history were evaluated. Plasma hs-CRP, big ET-1 levels and other clinical characteristics were compared among the groups.

Results

Patients with persistent AF had higher hs-CRP concentrations than those with paroxysmal AF (P < 0.05), both groups had higher hs-CRP level than controls (P < 0.05). Patients with persistent AF had higher big ET-1 level than those with paroxysmal AF, although the difference did not reach the statistical significance (P > 0.05), and both groups had higher big ET-1 levels than controls (P < 0.05). Multiple regression analyses revealed hs-CRP as an independent determinant of AF (P < 0.001). Further adjusted for big ET-1, both big ET-1 and hs-CRP were independent predictors for AF (P < 0.001), but the odds ratio for hs-CRP in predicting AF attenuated from 8.043 to 3.241. There was a positive relation between hs-CRP level and big ET-1 level in paroxysmal AF patients (r = 0.563, P < 0.05), however, the relationship in persistent AF patients was poor (r = 0.094, P < 0.05).

Conclusions

Both plasma hs-CRP and big ET-1 levels are elevated in lone AF patients, and are associated with AF. In paroxysmal lone AF patients, there were significant positive correlations between plasma hs-CRP level and big ET-1 level.

Initial Perioperative Care of the Cardiac Surgical Patient

Recently, changes in the management of cardiac patients have allowed earlier discharge from the cardiac recovery area and reduced hospital length of stay. These changes have been drien by a need to reduce the cost of cardiac surgery and imrove efficiency. This change has been both financially sucessful and safe for patients. To allow for this success, a joint effort is required between the departments of cardiac surgery and anesthesiology involving the preoperative, intraoperative and postoperative treatment of these patients. Through recogition of suitable candidates, modifications in anesthetic techique, and appropriate postoperative management, the goal of extubation within 6 hours of admission to the cardiac recovery area can be achieved. Changes in intraoperative and early postoperative management of cardiac surgical patients are discussed. Specific recovery models are reviewed with disussion of the parallel and integrated models. Methods of preicting prolonged extubation times and intensive care unit length of stay are also discussed. Initial management of the cardiac patient in the cardiac recovery area is presented with a more in-depth review of specific complications: stroke, atril fibrillation, blood loss, left ventricular dysfunction, and pulonary dysfunction.

Uncertainty and Its Antecedents in Patients With A trial Fibrillation

The aim of this descriptive, correlational, and cross-sectional survey was to explore uncertainty in patients with atrial fibrillation and to examine the relationships between uncertainty and its antecedents, including education, social support, and perceived seriousness of illness in patients newly diagnosed with atrial fibrillation. The theoretical framework of the study was Mishel’s middle-range nursing theory of uncertainty in illness. A convenience sample of 81 participants recruited from two academic medical centers over 10 months was interviewed. Uncertainty was moderately high in patients with atrial fibrillation compared to other clinical populations. Among antecedents of uncertainty, higher education was significantly associated with less uncertainty (= -.21 to -.25). Except for tangible support, persons with greater social supports perceived less uncertainty (= -.25 to -.27), and individuals with greater perceived seriousness of illness reported greater uncertainty (= .30 to .33).

Pharmacotherapy of Atrial Fibrillation

Atrial fibrillation is the most common sustained arrhythmia of clinical significance. Its prevalence rises with age. It is a significant cause of thromboembolic phenomena. We describe briefly the etiology and classification of atrial fibrillation, the risk factors for thromboembolism and stroke associated with it, the indications for hospitalization, and the therapeutic goal. We discuss in depth the management strategies for such patients and compare the impact of rate versus rhythm control in reducing morbidity and mortality attributed to arrhythmia, in light of past and present trials. A brief overview of the drugs used in the management of atrial fibrillation, their pharmacology and dosage, their effects and use in rhythm versus rate control with important side effects are also included. Finally, the prevention and treatment of thromboembolism in patients with atrial fibrillation, an important aspect of therapy, is revisited in light of recent advances.

Malnutrition, renal dysfunction and left ventricular hypertrophy synergistically increase the long-term incidence of cardiovascular events

Although malnutrition indicates an unfavorable prognosis in some clinical settings, the synergistic impact of nutritional state, renal dysfunction and left ventricular hypertrophy (LVH) on cardiovascular events is unknown. Among 338 patients aged 40-80 years who underwent echocardiographic evaluation between 2003 and 2005, 161 patients who were followed for >7 years were recruited. Malnutrition was defined as a geriatric nutritional risk index (GNRI) of ⩽96. The mean patient age was 63.5±9.2 years; the mean estimated glomerular filtration rate (eGFR) was 72.9±18.7 ml min(-1) per 1.73 m(2); the mean LV mass index was 114±33 g m(-)(2); and the mean GNRI was 100.4±6.0. Among the patients, 25% (n=40) had an eGFR of <60 ml min(-1) per 1.73 m(2), 29% (n=46) exhibited chronic kidney disease (CKD) and 37% (n=59) had LVH. During the follow-up period (median: 96 months), cardiovascular events were observed in 15 patients (9%). Kaplan-Meier curves showed a significantly higher incidence of cardiovascular events in patients with an eGFR of <60 ml min(-1) per 1.73 m(2) (log-rank P=0.007), a GNRI of ⩽96 (P=0.003) or LVH (P=0.010). In a Cox regression analysis, eGFR, LVH and GNRI were independent determinants of cardiovascular event incidence after adjusting for age, gender and the presence of hypertension and diabetes. Furthermore, the combination of LVH and lower GNRI was significantly associated with a higher rate of cardiovascular events not only in all patients but also in patients with CKD. In conclusion, malnutrition, low eGFR and LVH were independent determinants of cardiovascular event incidence; they synergistically increased rates of these events in the long term. The evaluation and management of LVH progression and the improvement of nutritional status are critical for preventing cardiovascular complications even in non-dialysis patients.

Left Ventricular Filling Pressure as Assessed by the E/e' Ratio Is a Determinant of Atrial Fibrillation Recurrence after Cardioversion

PURPOSE

Left ventricular (LV) filling pressure affects atrial fibrillation (AF) recurrence. We investigated the relationship between diastolic dysfunction and AF recurrence after cardioversion, and whether LV filling pressure was predictive of AF recurrence.

MATERIALS AND METHODS

Sixty-six patients (mean 58±12 years) with newly diagnosed persistent AF were retrospectively enrolled. We excluded patients with left atrial (LA) diameters larger than 50 mm, thereby isolating the effect of LV filling pressure. We evaluated the differences between the patients with (group 1) and without AF recurrence (group 2).

RESULTS

Group 1 showed increased LA volume index (LAVI) and E/e' compared to group 2 (p<0.05). During a mean follow-up period of 25±19 months, AF recurrence after cardioversion was 60.6% (40/66). The area under the receiver operating characteristics curve of E/e' for AF recurrence was 0.780 [95% confidence interval (CI): 0.657-0.903], and the optimal cut-off value of the E/e' was 9.15 with 75.0% of sensitivity and 73.1% of specificity. A Kaplan-Meier survival curve showed that the cumulative recurrence-free survival rate was significantly lower in patients with higher LV filling pressure (E/e'>9.15) compared with patients with lower LV filling pressure (E/e'≤9.15) (log rank p=0.008). Cox regression analysis revealed that E/e' [hazards ratio (HR): 1.100, 95% CI: 1.017-1.190] and LAVI (HR: 1.042, 95% CI: 1.002-1.084) were independent predictors for AF recurrence after cardioversion.

CONCLUSION

LV filling pressure predicts the risk of AF recurrence in persistent AF patients after cardioversion.

Cardioversion of uncomplicated paroxysmal atrial fibrillation: a survey of practice by Canadian emergency physicians

Objective:

Paroxysmal atrial fibrillation (PAF) is the rhythm disturbance most commonly encountered by emergency physicians, yet the role played by emergency physicians in the management of this condition has not been well described. The purpose of this study was to describe the management of uncomplicated PAF by Canadian emergency physicians.

Methods:

All members of the Canadian Association of Emergency Physicians with a Canadian address (n = 1255) were mailed a 15-point questionnaire regarding training/certification, hospital demographics and practice patterns regarding the management of uncomplicated PAF. Chisquared analysis and Fisher’s Exact test were performed to identify significant differences in reported practice patterns in relation to demographic variables. Significant associations were tested for interaction using the Mantel–Haenszel test.

Results:

We received 663 responses, representing a 52.8% response rate. Six hundred and twenty-two (95%), 514 (78%) and 242 (38%) respondents reported routine performance of rate control, chemical cardioversion and electrical cardioversion respectively. Physicians working in high-volume emergency departments (&gt;50 000 visits/yr) were significantly more likely to self-manage rate control and chemical/electrical cardioversion than those working in lower volume emergency departments. Residency training was associated with higher performance of electrical (44% v. 31%, p &lt; 0.01) but not chemical cardioversion or rate control, although, amongst residency trained physicians, those with FRCP-level training were significantly more likely to perform both chemical (86% v. 76%, p &lt; 0.05) and electrical (57% v. 37%, p &lt; 0.01) cardioversion.

Conclusion:

Canadian emergency physicians surveyed in this study actively manage uncomplicated PAF. We found significant variations in practice, especially related to the use of electrical cardioversion. This may reflect different practice environments, levels of training, and lack of evidence to guide best practice. Further research is required to determine the optimal care of PAF in the emergency department setting.

Prevention of Venous Thromboembolism After Stroke

Venous thromboembolism (VTE) is a common complication following acute ischemic and hemorrhagic stroke. Pulmonary embolism (PE), the most serious consequence of deep vein thrombosis (DVT), can result in significant morbidity and death. Patients with stroke are at particular risk because of limb paralysis, prolonged bed rest, and increased prothrombotic activity. Preventive measures should be taken at all levels of care and can include mechanical calf compression, antiplatelet agents, and the use of anticoagulants such as heparin and low molecular weight heparin. Prevention of VTE should be incorporated into all stroke care pathways.

Postoperative atrial fibrillation in patients undergoing non-cardiac non-thoracic surgery: A practical approach for the hospitalist

New postoperative atrial fibrillation (POAF) is the most common perioperative arrhythmia and its reported incidence ranges from 0.4 to 26% in patients undergoing non-cardiac non-thoracic surgery. The incidence varies according to patient characteristics such as age, presence of structural heart disease and other co-morbidities, as well as the type of surgery performed. POAF occurs as a consequence of adrenergic stimulation, systemic inflammation, or autonomic activation in the intra or postoperative period (e.g. due to pain, hypotension, infection) in the setting of a susceptible myocardium and other predisposing factors (e.g. electrolyte abnormalities). POAF develops between day 1 and day 4 post-surgery and it is often considered a self-limited entity. Its acute management involves many of the same strategies used in non-surgical patients but the optimal long-term management is challenging because of the limited available evidence. Several studies have shown an association between occurrence of POAF and in-hospital morbidity, mortality, and length of stay. Although, traditionally, POAF was considered to have a generally favorable long-term prognosis, recent data have shown an association with an increased risk of stroke at 1 year after hospitalization. It is unknown, however, whether strategies to prevent POAF or for rate/rhythm control when it does occur, lead to a reduction in morbidity or mortality. This suggests the need for future studies to better understand the risks associated with POAF and to determine optimal strategies to minimize long-term thromboembolic risks. In this article, we summarize the current knowledge on epidemiology, pathophysiology, and short- and long-term management of POAF after non-cardiac non-thoracic surgery with the goal of providing a practical approach to managing these patients for the non-cardiologist clinician.

Blood stasis may cause thrombosis in the left superior pulmonary vein stump after left upper lobectomy

Background

We previously reported that arterial infarction of vital organs after lobectomy might occur only after left upper lobectomy and be caused by thrombosis in the left superior pulmonary vein stump. We hypothesized that changes in blood flow, such as blood stasis and disturbed stagnant flow, in the left superior pulmonary vein stump cause thrombosis, and this was evaluated by intraoperative ultrasonography.

Methods

From July 2013 to April 2014, 24 patients underwent lobectomy in the Steel Memorial Muroran Hospital. During the procedure, an ultrasound probe was placed at the pulmonary vein stump and the velocity in the stump was recorded with pulse Doppler mode. The peak velocity and the presence of spontaneous echo contrast in the stump were evaluated. After the operation, the patients underwent contrast-enhanced CT within 3 months.

Results

The operative procedures were seven left upper lobectomies, four left lower lobectomies, seven right upper lobectomies, and six right lower lobectomies. Blood flow was significantly slower in the left superior pulmonary vein stump than in the right pulmonary vein stumps. However, that was not significantly slower than that in the left inferior pulmonary vein stump. Spontaneous echo contrast in the pulmonary vein stump was seen in three patients who underwent left upper lobectomy. Of the three patients with spontaneous echo contrast, two patients developed thrombosis in the left superior vein stump within 3 months after the operation. There was no patient who developed arterial infarction.

Conclusions

In patients who underwent left upper lobectomy, intraoperative ultrasonography to evaluate blood flow and the presence of spontaneous echo contrast in the left superior pulmonary vein stump may be useful to predict thrombosis that may cause arterial infarction.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-014-0159-8) contains supplementary material, which is available to authorized users.

Efficacy of dronedarone versus propafenone in the maintenance of sinus rhythm in patients with atrial fibrillation after electrical cardioversion

PURPOSE

Our objective was to compare the efficacy of dronedarone and propafenone in maintaining sinus rhythm in patients with atrial fibrillation (AF) after electrical cardioversion.

METHODS

In this single-center, open-label, randomized trial, we randomly assigned patients with AF after electrical cardioversion to receive dronedarone 400 mg BID or propafenone 150 mg TID. Follow-up clinical evaluations were conducted at 1, 2, 3, and 6 months of treatment. The primary end point was the time to the first recurrence of AF.

FINDINGS

A total of 98 patients were enrolled (79 men; mean age, 59.2 years; n = 49 per group). The median times to first recurrence of AF were 31 days in the dronedarone group and 32 days in the propafenone group (P = 0.715). The median (interquartile range) ventricular rates at first recurrence of AF were 76.5 (67.3-86.5) beats/min in the dronedarone group and 83.0 (71.0-96.0) beats/min in the propafenone group (P = 0.059).

IMPLICATIONS

Dronedarone and propafenone had similar efficacies in maintaining sinus rhythm in patients with AF after electrical cardioversion. The ventricular rate at the first recurrence of AF was numerically but not statistically significantly lower in the dronedarone group than in the propafenone group. ClinicalTrials.gov identifier: NCT01991119.

Association between Doppler flow of atrial fibrillatory contraction and recurrence of atrial fibrillation after electrical cardioversion

BACKGROUND

Left atrial fibrillatory contraction (Afc) flow can be frequently observed interspersed between two successive mitral E waves in patients with atrial fibrillation (AF). The aim of this study was to test the hypothesis that Afc is related to the maintenance of sinus rhythm after electrical cardioversion for AF.

METHODS

In this retrospective study, the records of a total of 137 patients with AF who underwent successful electrical cardioversion were examined. Conventional echocardiographic measurements, including left atrial volume index (LAVI), were obtained, and the appearance of Afc flow was also evaluated before cardioversion. Patients were followed to a clinical end point defined as recurrent AF during the study period.

RESULTS

AF recurrence was noted in 100 patients (73%) over a mean follow-up period of 5 months. The patients with recurrent AF had greater LAVI and left atrial dimensions and had a lower frequency of Afc flow (57.0% vs 86.5%, P < .001): both the velocity and velocity-time integral (VTI) of Afc flow significantly decreased. Receiver operating characteristic curve analysis showed that the Afc flow VTI and velocity had stronger associations with AF recurrence than did LAVI (areas under the curve: VTI, 0.96; velocity, 0.86; LAVI, 0.71). A VTI of 3.1 cm and velocity of 32 cm/sec for Afc flow were the best cutoff values for AF recurrence. Afc flow VTI (hazard ratio, 0.70; 95% confidence interval, 0.51-0.96) and velocity (hazard ratio, 0.97; 95% confidence interval, 0.94-0.99) were significantly related to AF recurrence in a multivariate Cox regression analysis.

CONCLUSIONS

Return of AF after successful electrical cardioversion may be associated with Afc Doppler flow velocity and VTI measured immediately before cardioversion.

Management of Atrial Fibrillation

Atrial fibrillation remains the most prevalent cardiac arrhythmia, and its incidence is increasing as the population ages. Common conditions associated with an increased incidence include advanced age, hypertension, heart failure, and valvular heart disease. Patients with atrial fibrillation may complain of palpitations, fatigue, and decreased exercise tolerance or may be completely asymptomatic. Options for treating patients who experience atrial fibrillation include rate-controlling drugs such as digoxin, β-blockers, and calcium channel blockers or a rhythm-controlling strategy with agents such as sodium channel blockers and potassium channel blockers. Atrial fibrillation increases the risk of stroke due to atrial thrombus formation and embolization. Anticoagulation with the vitamin K antagonist, warfarin, remains the most widely prescribed treatment option to decrease stroke risk. Several other antithrombotic agents have recently become available and offer excellent alternatives to warfarin. Catheter ablation can be undertaken as a nonpharmacologic rhythm control option with varying degrees of success depending on duration of atrial fibrillation and follow-up time from the procedure. This review article further describes the management options for patients presenting with atrial fibrillation.

Rationale and design of the eXplore the efficacy and safety of once-daily oral riVaroxaban for the prEvention of caRdiovascular events in patients with nonvalvular aTrial fibrillation scheduled for cardioversion trial: A comparison of oral rivaroxaban once daily with dose-adjusted vitamin K antagonists in patients with nonvalvular atrial fibrillation undergoing elective cardioversion

BACKGROUND

Anticoagulation before, during, and after cardioversion is effective in reducing stroke risk in patients with atrial fibrillation.

OBJECTIVE

The objective of this study is to explore the efficacy and safety of rivaroxaban 20 mg once daily (15 mg if creatinine clearance is 30-49 mL/min) compared with dose-adjusted vitamin K antagonists (VKAs; international normalized ratio 2.0-3.0) in patients scheduled for elective cardioversion.

METHODS

This is a prospective, randomized, open-label, parallel group comparison of approximately 1,500 patients from 17 countries with hemodynamically stable nonvalvular atrial fibrillation of >48 hours or unknown duration. Patients will be randomized 2:1 (rivaroxaban:VKA) using 2 cardioversion strategies: the first approach is early cardioversion with the precardioversion anticoagulation goal of 1 to 5 days using rivaroxaban or usual therapy (heparin + VKA). In these patients, transesophageal echocardiography will be encouraged to exclude atrial thrombi. The alternative approach is delayed cardioversion. Rivaroxaban or VKA will be administered for 21 to 56 days before cardioversion. All patients will receive study treatment for 6 weeks postcardioversion. The primary efficacy end point is a composite of all strokes, transient ischemic attacks, noncentral nervous system systemic emboli, myocardial infarctions, and cardiovascular deaths. Each primary end point component will be evaluated separately, and additional composites will be investigated. The principal safety end point is major bleeding.

CLINICAL CONTEXT

This will be the first prospective study of a novel oral anticoagulant in the setting of cardioversion. It will provide important information regarding the use of rivaroxaban in the periods preceding and after cardioversion in a broad patient population.