Management of atrial fibrillation

Bleeding Events Associated with Rivaroxaban Therapy in Naive Patients with Nonvalvular Atrial Fibrillation: A Longitudinal Study from a Genetic Perspective with INR Follow-Up

Background and Objectives: Rivaroxaban is a direct-acting anticoagulant used to prevent stroke in patients with atrial fibrillation. Rivaroxaban is a substrate for P-glycoprotein, which is encoded by the ABCB1 gene. Rivaroxaban is also metabolized by the CYP3A5 gene. Therefore, the current study is carried out to study the effects of polymorphisms in the ABCB1 and CYP3A5 genes, which may affect the plasma levels of rivaroxaban, with subsequent clinical outcomes (bleeding events) associated with the therapy. Materials and Methods: The study was conducted on 66 naive patients with atrial fibrillation treated with rivaroxaban. Blood samples of rivaroxaban were taken at 3 h and after 1 month following the administration of the drug to measure plasma levels. The blood level of rivaroxaban was measured with an HPLC-UV detector. Sanger sequencing was used to find polymorphisms in the targeted genes. Coagulation parameters were measured at 3 h and after 1 month of administration of rivaroxaban. Frequencies of bleeding events were recorded throughout the one-month course of drug therapy. Results: The heterozygous and homozygous mutant genotypes of ABCB1 (rs2032582, rs1045642, rs1128503, and rs4148738) and CYP3A5 (rs776746) showed lower plasma concentrations as compared to the wild-type genotype. ABCB1 (rs2032582, rs1045642, rs1128503, and rs4148738) and CYP3A5 (rs776746) gene polymorphisms had a statistically significant impact on the plasma concentration of rivaroxaban among the heterozygous and homozygous mutant genotypes compared to the wild-type genotype. The heterozygous variant of ABCB1 and homozygous variant of CYP3A5 suffered more events of bleeding. Conclusions: It was concluded that ABCB1 (rs2032582, rs1045642, rs1128503, and rs4148738) and CYP3A5 (rs776746) gene polymorphisms had a significant impact on the plasma levels of rivaroxaban in patients treated for atrial fibrillation on day three as well as after one month of the therapy. The lowest plasma levels were observed in patients with a homozygous variant of ABCB1 (rs2032582, rs1045642, or rs4148738) along with the CYP3A5*1/*3 allele. The heterozygous variant of ABCB1 SNPs and homozygous variant of CYP3A5 SNPs suffered more events of bleeding.

Rational quinidine dosage regimen for atrial fibrillation in Thoroughbred racehorses based on population pharmacokinetics

Introduction

Quinidine (QND) sulfate is an effective treatment for atrial fibrillation (AF) in horses, and several dosage regimens have been proposed to address its wide variability in response and potential adverse effects. The purpose of this study was to analyze the variability in plasma quinidine concentrations using population pharmacokinetics to determine an effective and safe dosage regimen for Thoroughbred horses.

Methods

Six healthy Thoroughbred horses were treated with 20 mg/kg quinidine sulfate dihydrate (16.58 mg/kg QND base) administered PO or 5 mg/kg quinidine hydrochloride monohydrate (4.28 mg/kg QND base) administered IV (single administration), and blood samples were taken regularly. Four healthy horses were treated with 20 mg/kg quinidine sulfate dihydrate administered twice (every 6 h) via PO route. For the other 19 Thoroughbred racehorses that developed AF, blood samples were taken during quinidine therapy. Quinidine concentrations were measured in all plasma samples using liquid chromatography with tandem mass spectrometry, and the data from 29 horses were modeled using a nonlinear mixed-effects model, followed by Monte Carlo simulations (MCS).

Results

The median quinidine concentration for successful sinus rhythm conversion was 2.0 μg/mL (range: 0.5-2.7 μg/mL) in AF horses, while a median concentration of 3.8 μg/mL (range: 1.6-5.1 μg/mL) showed adverse effects. MCS predicted that plasma quinidine concentrations for quinidine sulfate dihydrate PO administration (loading dose: 30 mg/kg, maintenance dose: 6.5 mg/kg q 2 h) reached 1.4, 2.0 and 2.7 μg/mL in 90, 50 and 10% of the horse populations, respectively. Increasing the loading dose to 45 mg/kg and the maintenance dose to 9 mg/kg q 2 h, the plasma concentrations achieved were 1.9, 2.8, and 3.8 μg/mL in 90, 50, and 10% of horse populations, respectively.

Discussion

Using simulations, different empirical dosing regimens were proposed to achieve plasma quinidine concentrations immediately or progressively, representing a tradeoff between optimizing therapeutic effects and minimizing adverse effects. A combination of these dosing regimens is recommended to gradually increase the therapeutic concentration levels of quinidine for safe and effective treatment of AF in racehorses.

Outcomes and atrial substrate analysis in patients with HIV undergoing atrial fibrillation ablation

INTRODUCTION

Patients with HIV infection have increased risk of atrial fibrillation, but the pathophysiologic mechanisms and the utility of catheter ablation in this population are not well-studied. We aimed to characterize outcomes of atrial fibrillation ablation and left atrial substrate in patients with HIV.

METHODS

The study was a retrospective propensity score-matched analysis of patients with and without HIV undergoing atrial fibrillation ablation. A search was performed in the electronic medical record for all patients with HIV who received initial atrial fibrillation ablation from 2011 to 2020. After calculating propensity scores for HIV, matching was performed with patients without HIV by using nearest-neighbor matching without replacement in a 1:2 ratio. The primary outcome was freedom from atrial arrhythmia and secondary outcomes were freedom from atrial fibrillation, freedom from atrial tachycardia, and freedom from repeat ablation, compared by log-rank analysis. The procedures of patients with HIV who underwent repeat ablation at our institution were further analyzed for etiology of recurrence. To further characterize the left atrial substrate, a subsequent case-control analysis was then performed for a set of randomly chosen 10 patients with HIV matched with 10 without HIV to compare minimum and maximum voltage at nine pre-specified regions of the left atrium.

RESULTS

Twenty-seven patients with HIV were identified. All were prescribed antiretroviral therapy at time of ablation. These patients were matched with 54 patients without HIV by propensity score. 86.4% of patients with HIV and 76.9% of controls were free of atrial fibrillation or atrial tachycardia at 1 year (p = .509). Log-rank analysis showed no difference in freedom from atrial arrhythmia (p value .971), atrial fibrillation (p-value .346), atrial tachycardia (p value .306), or repeat ablation (p value .401) after initial atrial fibrillation ablation in patients with HIV compared to patients without HIV. In patients with HIV with recurrent atrial fibrillation, the majority had pulmonary vein reconnection (67%). There were no significant differences in minimum or maximum voltage at any of the nine left atrial regions between the matched patients with and without HIV.

CONCLUSIONS

Ablation to treat atrial fibrillation in patients with HIV, but without overt AIDS is frequently successful therapy. The majority of patients with recurrence of atrial fibrillation had pulmonary vein reconnection, suggesting infrequent nonpulmonary vein substrate. In this population, the left atrial voltage in patients with HIV is similar to that of patients without HIV. These findings suggest that the pulmonary veins remain a critical component to the initiation and maintenance of atrial fibrillation in patients with HIV.

Comment on Alghnam et al. The Association between Obesity and Chronic Conditions: Results from a Large Electronic Health Records System in Saudi Arabia. Int. J. Environ. Res. Public Health 2021, 18, 12361

I have read the interesting and informative paper recently published by Alghnam and colleagues that examined associations between obesity and diabetes (DM) and hypertension (HTN) [...].

Thromboembolic Risk in Patients With Pneumonia and New-Onset Atrial Fibrillation Not Receiving Anticoagulation Therapy

IMPORTANCE

New-onset atrial fibrillation (AF) is commonly reported in patients with severe infections. However, the absolute risk of thromboembolic events without anticoagulation remains unknown.

OBJECTIVE

To investigate the thromboembolic risks associated with AF in patients with pneumonia, assess the risk of recurrent AF, and examine the association of initiation of anticoagulation therapy with new-onset AF.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used linked Danish nationwide registries. Participants included patients hospitalized with incident community-acquired pneumonia in Denmark from 1998 to 2018. Statistical analysis was performed from August 15, 2021, to March 12, 2022.

EXPOSURES

New-onset AF.

MAIN OUTCOMES AND MEASURES

Thromboembolic events, recurrent AF, and all-cause death. Estimated risks were calculated for thromboembolism without anticoagulation therapy, new hospital or outpatient clinic contact with AF, initiation of anticoagulation therapy, and all-cause death at 1 and 3 years of follow-up. Death was treated as a competing risk, and inverse probability of censoring weights was used to account for patient censoring if they initiated anticoagulation therapy conditioned on AF.

RESULTS

Among 274 196 patients hospitalized for community-acquired pneumonia, 6553 patients (mean age [SD], 79.1 [11.0] years; 3405 women [52.0%]) developed new-onset AF. The 1-year risk of thromboembolism was 0.8% (95% CI, 0.8%-0.8%) in patients without AF vs 2.1% (95% CI, 1.8%-2.5%) in patients with new-onset AF without anticoagulation; this risk was 1.4% (95% CI, 1.0%-2.0%) among patients with AF with intermediate stroke risk and 2.8% (95% CI, 2.3%-3.4%) in patients with AF with high stroke risk. Three-year risks were 3.5% (95% CI, 2.8%-4.3%) among patients with intermediate stroke risk and 5.3% (95% CI, 4.4%-6.5%) among patients with high stroke risk. Among patients with new-onset AF, 32.9% (95% CI, 31.8%-34.1%) had a new hospital contact with AF, and 14.0% (95% CI, 13.2%-14.9%) initiated anticoagulation therapy during the 3 years after incident AF diagnosis. At 3 years, the all-cause mortality rate was 25.7% (95% CI, 25.6%-25.9%) in patients with pneumonia without AF vs 49.8% (95% CI, 48.6%-51.1%) in patients with new-onset AF.

CONCLUSIONS AND RELEVANCE

This cohort study found that new-onset AF after community-acquired pneumonia was associated with an increased risk of thromboembolism, which may warrant anticoagulation therapy. Approximately one-third of patients had a new hospital or outpatient clinic contact for AF during the 3-year follow-up, suggesting that AF triggered by acute infections is not a transient, self-terminating condition that reverses with resolution of the infection.

Inflammation as a risk factor for stroke in atrial fibrillation: data from a microarray data analysis

Objective

Stroke is a severe complication of atrial fibrillation (AF). We aimed to discover key genes and microRNAs related to stroke risk in patients with AF using bioinformatics analysis.

Methods

GSE66724 microarray data, including peripheral blood samples from eight patients with AF and stroke and eight patients with AF without stroke, were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between AF patients with and without stroke were identified using the GEO2R online tool. Functional enrichment analysis was performed using the DAVID database. A protein–protein interaction (PPI) network was obtained using the STRING database. MicroRNAs (miRs) targeting these DEGs were obtained from the miRNet database. A miR–DEG network was constructed using Cytoscape software.

Results

We identified 165 DEGs (141 upregulated and 24 downregulated). Enrichment analysis showed enrichment of certain inflammatory processes. The miR–DEG network revealed key genes, including MEF2A, CAND1, PELI1, and PDCD4, and microRNAs, including miR-1, miR-1-3p, miR-21, miR-21-5p, miR-192, miR-192-5p, miR-155, and miR-155-5p.

Conclusion

Dysregulation of certain genes and microRNAs involved in inflammation may be associated with a higher risk of stroke in patients with AF. Evaluating these biomarkers could improve prediction, prevention, and treatment of stroke in patients with AF.

A Comparison of Rate Control Agents for the Treatment of Atrial Fibrillation: Follow-Up Investigation of the AFFIRM Study

There are limited data from randomized controlled trials comparing rate control agents in atrial fibrillation. Patient-level data from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial was used to compare outcomes in patients randomized to the rate control arm who were treated with a single rate control agent at baseline. The rate control agents used were beta-blockers, non-dihydropyridine calcium channel blockers, and digoxin. The independent variable for this analysis was the initial study drug used and the dependent variables were time to first hospitalization and time to death from any cause. We analyzed 1,144 out of 2,027 participants assigned to the rate control group who were on a single rate control agent at the start of the trial. There were 485 (42.5%) participants in the beta-blocker group, 344 (30%) in the calcium channel blocker group, and 315 (27.5%) in the digoxin group. All hospitalization and all-cause mortality occurred in 55.9% and 12.5% of those in the beta-blocker group, 58.4% and 16.7% in the calcium channel blocker group, and 55.2% and 21.1% in the digoxin group, respectively. After adjustment for differences in baseline characteristics, there were no significant differences in time to hospitalization or death for any group. In the AFFIRM trial, the initial rate control drug used was not associated with statistically significant differences in time to hospitalization or death after controlling for differences in baseline characteristics. There is limited data at present to guide the selection of rate control agents in patients with atrial fibrillation.

Fetal cardiomyocyte phenotype, ketone body metabolism, and mitochondrial dysfunction in the pathology of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia diagnosed in clinical practice. Even though hypertension, congestive heart failure, pulmonary disease, and coronary artery disease are the potential risk factors for AF, the underlying molecular pathology is largely unknown. The reversion of the mature cardiomyocytes to fetal phenotype, impaired ketone body metabolism, mitochondrial dysfunction, and the cellular effect of reactive oxygen species (ROS) are the major underlying biochemical events associated with the molecular pathology of AF. On this background, the present manuscript sheds light into these biochemical events in regard to the metabolic derangements in cardiomyocyte leading to AF, especially with respect to structural, contractile, and electrophysiological properties. In addition, the article critically reviews the current understanding, potential demerits, and translational strategies in the management of AF.

Regulatory role of cardiomyocyte metabolism via AMPK activation in modulating atrial structural, contractile, and electrical properties following atrial fibrillation

The number of patients diagnosed with atrial fibrillation (AF) has been rising due to increased incidence, enhanced detection methods, and greater survival rates following diagnosis. Due to this increase, AF is now the most commonly diagnosed arrhythmia in clinical practice. AF is characterized by irregular, high-frequency contractions of atrial myocytes that lead to turbulent blood flow and the potential for thrombus formation, stroke, or heart failure. These high-frequency contractions of the atrial myocytes cause an imbalance between metabolic supply and demand. Although advances have been made in understanding the pathophysiology of AF, the etiology and underlying pathogenic mechanism remain unknown. However, recent evidence suggests that cardiomyocyte metabolism involving 5' AMP-activated protein kinase (AMPK) activation is altered in patients with AF. Here, we critically reviewed the current understanding of AMPK activation in AF and how it could affect structural, contractile, and electrophysiological cellular properties in the pathogenesis of AF.

Imaging for Patient's Selection and Guidance of LAA and ASD Percutaneous and Surgical Closure

This review comprises 2 main subjects: the percutaneous and surgical closure of the left atrial appendage (LAA) and atrial septal defect (ASD). The aim of the authors was to provide a detailed description of: 1) anatomy of LAA, normal interatrial septum, and the various types of ASD as revealed by noninvasive imaging techniques; 2) preprocedure planning of secundum ASD and LAA percutaneous closure; 3) key steps of the procedural guidance emphasizing the role of 2-dimensional/3-dimensional transesophageal echocardiography; and 4) surgical closure of LAA and ASD.

Predicting Cost-Effectiveness of Generic vs. Brand Dabigatran Using Pharmacometric Estimates Among Patients with Atrial Fibrillation in the United States

Generic entry of newer anticoagulants is expected to decrease the costs of atrial fibrillation management. However, when making switches between brand and generic medications, bioequivalence concerns are possible. The objectives of this study were to predict and compare the lifetime cost‐effectiveness of brand dabigatran with hypothetical future generics. Markov microsimulations were modified to predict the lifetime costs and quality‐adjusted life years of patients on either brand or generic dabigatran from a US private payer perspective. Event rates for generics were predicted using previously developed pharmacokinetic‐pharmacodynamic models. The analyses showed that generic dabigatran with lower‐than‐brand systemic exposure were dominant. Meanwhile, generic dabigatran with extremely high systemic exposure was not cost‐effective compared with the brand reference. Cost‐effectiveness of generic medications cannot always be assumed as shown in this example. Combined use of pharmacometric and pharmacoeconomic models can assist in decision making between brand and generic pharmacotherapies.

Prevalence of atrial fibrillation, oral anticoagulation prescription and associated factors in Brazilian older adults

INTRODUCTION: Atrial fibrillation increases five times the risk of stroke. Anticoagulation reduces the incidence of cerebrovascular events. However, many patients do not receive thromboprophylaxis. OBJECTIVES: To estimate the prevalence of atrial fibrillation in the elderly at a Brazilian university hospital and the proportion of anticoagulation prescription. Secondary objectives were to identify the therapeutic options, the main reasons for non-prescription and the factors associated with ineffectiveness or lack of treatment. METHOD: cross-sectional study with a consecutive sample of 1,630 outpatients selected at Hospital de Clínicas de Porto Alegre between April and June of 2017. Atrial fibrillation was identified in 220 (13.50%) individuals. Medical records from 145 patients were accessed, followed by a telephone interview. The association between variables and outcomes was checked using the Mann-Whitney’s U Test and the binary logistic regression. RESULTS: The prevalence of atrial fibrillation was 13.50%. Anticoagulation therapy was prescribed in 77.93% of cases. In 76.11% of patients, warfarin was the chosen drug. There was a tendency towards no prescription in patients with previous bleeding (RR = 2.32; 95%CI 0.95 – 5.64; p = 0.06) and falls (RR = 2.02; 95%CI 0.82 – 5.03; p = 0.08). We found an association between reduced functional capacity (Barthel’s Activities of Daily Living Score < 80) and higher rate of anticoagulation in therapeutic aim (RR = 0.22; 95%CI 0.06 – 0.87; p = 0.04). CONCLUSION: The prevalence of atrial fibrillation in this population was 13.50% and in 77.93% of cases anticoagulant were prescribed. Functional impairment was associated with a higher rate of anticoagulation in therapeutic aim.

Nonvitamin K Antagonist Oral Anticoagulants Versus Warfarin in Atrial Fibrillation Patients and Risk of Dementia: A Nationwide Propensity-Weighted Cohort Study

Background It is unclear whether nonvitamin K antagonist oral anticoagulants ( NOAC s) can mitigate dementia development in atrial fibrillation. We compared dementia development among users of NOACs or warfarin in patients with atrial fibrillation with no prior neurological diagnoses. Methods and Results We conducted a Danish nationwide cohort study including 33 617 new oral anticoagulant users with nonvalvular atrial fibrillation, of which 11 052 were aged 60 to 69 years, 13 237 were aged 70 to 79 years, and 9238 were aged 80 years and older. To exclude prevalent non -oral anticoagulants- associated dementia, we considered the at-risk population of patients alive and free of dementia at 180 days following inclusion. We compared rates of new-onset dementia by age and treatment regimen using inverse probability of treatment weighting to account for confounding. Approximately 60% of patients were NOAC users and 40% were warfarin users. Mean follow-up was 3.4 years. Dementia occurred in 41 patients aged 60 to 69 years, 276 patients aged 70 to 79 years, and 441 patients aged 80 years and older. Relative to warfarin users, dementia rates were nonsignificantly lower among NOAC users aged 60 to 69 years (0.11 events/100 person-years versus 0.12 events/100 person-years; weighted hazard ratio, 0.92 [95% CI, 0.48-1.72]) and NOAC users aged 70 to 79 years (0.64 events/100 person-years versus 0.78 events/100 person-years; weighted hazard ratio , 0.86 [95% CI, 0.68-1.09]), whereas NOAC s were associated with significantly higher dementia rates (2.16 events/100 person-years versus 1.70 events/100 person-years; weighted hazard ratio , 1.31 [95% CI, 1.07-1.59]) in patients 80 years and older. Conclusions This nationwide cohort of patients with atrial fibrillation revealed no clinically meaningful difference in dementia development between users of NOACs or warfarin apart from a higher risk in NOAC users 80 years and older, which may relate to residual confounding from selective prescribing and unobserved comorbidities.

New-onset atrial fibrillation in patients with acute coronary syndrome may be associated with worse prognosis and future heart failure

BACKGROUND

The purpose of this study was to evaluate the prognostic value of atrial fibrillation (AF) in patients with acute coronary syndrome (ACS).

METHODS

A total 648 of consecutive ACS patients were divided into non-AF and all-AF groups. The all-AF group was further subdivided into new-onset AF and pre-existing AF groups. We compared prognosis among these groups using the Cox regression analysis.

RESULTS

The mean follow-up period was 1.4 ± 1.2 years. Overall patient numbers were 538 in non-AF and 110 in all-AF groups (67 in new-onset AF and 43 in pre-existing AF). Seventy-eight all-cause deaths and 42 cardiac deaths were observed. New-onset AF had a worse prognosis than the other groups in the Kaplan-Meier analysis (P = 0.025) after observation. Cox regression analysis indicated no significant difference for all-cause death among the three groups. The hazard ratio of congestive heart failure requiring hospitalization was significantly higher in the all-AF and new-onset AF group than in the non-AF group. Multivariate logistic regression analysis revealed that renal dysfunction, peripheral arterial disease, Killip classification ≥2, and left ventricular ejection fraction (LVEF) were independent predictors of all-cause death. The new-onset AF group had the highest prevalence of Killip classification ≥2 and the lowest LVEF.

CONCLUSION

In our study, AF was not an independent predictor of all-cause death, but new-onset AF may be associated with worse prognosis and future heart failure.

Management of Atrial Fibrillation in Patients with Heart Failure: Time to Implement Ablation Control

PURPOSE OF THE REVIEW

Atrial fibrillation (AF) in patients with heart failure and reduced systolic ejection fraction (HFrEF) is common and associated with increased morbidity and mortality, and managing AF in this population has been particularly challenging with sparse data regarding the optimal treatment strategy.

RECENT FINDINGS

Recent data suggests that rhythm control with catheter ablation can be of particular benefit to patients with coexisting AF and HFrEF. Recent randomized control trials actually suggest that catheter ablation could potentially improve mortality in this particular patient population. This is in stark contrast to the current practice recommendations that reserve catheter ablation for symptomatic AF in the general population. In this paper, we will review the most current randomized controlled studies using catheter ablation in HFrEF patients with the hope to increase awareness of the potential mortality benefits the need for prioritization of catheter ablation in HFrEF patients in the next AF management guidelines.

Revisiting the Role of Antiarrhythmic Drugs in Prevention of Atrial Fibrillation Recurrence: A Single Center Retrospective Review

Background

We conducted a retrospective analysis to revisit the efficacy of four different commonly used antiarrhythmic drugs (AADs) in a single community hospital setting in the U.S. We used cardiac implantable electronic devices (CIEDs) to continuously monitor the patients for maintenance of sinus rhythm. The CIEDs in our study included insertable cardiac monitor (ICM), permanent pacemaker (PPM) and cardiac resynchronization therapy-defibrillator (CRT-D). The aim was to compare efficacy of commonly used AADs for maintenance of sinus rhythm in atrial fibrillation (AF) patients.

Methods

We conducted our retrospective study in a real world practice setting. We analyzed electronic medical records of 145 consecutive patients with paroxysmal and persistent AF who were treated with AADs for maintenance of sinus rhythm between the period of April 2014 and February 2018.

Results

Total 34 out of 145 patients (23.45%) had AF recurrence. The mean duration of first AF recurrence in total patient cohort was 18.01 ± 12 months. There was no major difference in efficacy in terms of prevention of first episode of AF recurrence among commonly used class III and class IC AADs.

Conclusions

Higher doses clearly seem to be more effective in preventing the recurrence of AF in class III AADs; sotalol and amiodarone. Use of CIEDs helps to continuously monitor patients for recurrence of AF and detects proarrhythmic effects of AADs.

Dielectric permittivity change detects the process of blood coagulation: Comparative study of dielectric coagulometry with rotational thromboelastometry

BACKGROUND

Intravascular thrombus formation causes various cardiovascular diseases. To monitor coagulation is important for screening native status, prevention from bleeding and maintaining it within its therapeutic range. The prothrombin time and the activated partial thromboplastin time are widely used for assessment and recognized as the conventional methods. Prothrombin time methods employ enhancement of coagulation with thromboplastin. Since the laboratory data depend on the production lot and/or the manufacturer, the accurate methods are required for evaluation. Rotational thromboelastometry (ROTEM) is a method based on detection of the change in resistance to rotational movement during blood clotting, while dielectric blood coagulometry (DBCM) is a novel method for assessment of clotting by measuring the change of electrical permittivity. These methods are thus based on the technology for observation of different physical phenomena. The aim of this study was to compare parameters such as the clotting time obtained by ROTEM and DBCM to evaluate their clinical usefulness.

METHODS AND RESULTS

ROTEM and DBCM parameters were measured in 128 patients. The ROTEM clotting time showed a significant positive correlation with the DBCM coagulation time (R=0.707, p<0.001). Comparison of the DBCM coagulation time between patients with and without anticoagulant therapy (including novel oral anticoagulants) revealed a significant difference (43.8±11.9min in the anticoagulant group vs 29.4±8.3min in the control group, p<0.001). Evaluation of coagulation was equivalent with DBCM and ROTEM.

CONCLUSIONS

The present study suggested that DBCM, a novel method for measuring blood clotting, could provide the detail assessment for the status of anticoagulant therapy.

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.

Left atrial function following surgical ablation of atrial fibrillation: prospective evaluation using dual-source cardiac computed tomography

PURPOSE

The Maze procedure has shown excellent efficacy in the elimination of atrial fibrillation (AF); however, little is known about the quality of functional recovery in the left atrium (LA) following successful sinus rhythm conversion by the Maze procedure.

MATERIALS AND METHODS

We prospectively enrolled 12 patients (aged 52.5±10.1 years, 1 female) with valvular AF undergoing mitral valve surgery combined with the Maze procedure. Parameters of LA function in three anatomic compartments [anterior, posterior, and LA appendage (LAA)] were evaluated using electrocardiography-gated dual-source cardiac CT at one month and at six months after surgery. Twelve subjects matched by age, gender, and body surface area served as controls.

RESULTS

At one month after surgery, ejection fraction (EF) and emptying volume (EV) of the LA were 14.9±7.4% and 21.3±9.7 mL, respectively, and they were significantly lower than those of the control group (EF, 47.9±11.2%; EV, 46.0±10.7%; p<0001). These values did not significantly change throughout late periods (p=0.22 and 0.21, respectively). Functional contributions of the anterior, posterior, and appendage compartments (EV of each compartment/overall EV) were 80.4%, -0.9%, and 20.5%, respectively, for those with LAA preservation (n=6); 100.1%, -0.1%, and 0% for those with LAA resection (n=6; p<0.05); and 62.2%, 28.2%, and 9.7% in the control subjects (p<0.001).

CONCLUSION

Contractile functions of the LA significantly decreased after the Maze procedure. Functional contributions of three compartments of the LA were also altered. The influence of LAA preservation on postoperative LA functions needs to be evaluated through studies of larger populations.

Balancing ischaemia and bleeding risks with novel oral anticoagulants

Vitamin K antagonists (VKAs) have long been the standard of care for treatment of venous thromboembolism (VTE), and thromboprophylaxis in atrial fibrillation (AF). Despite their efficacy, their use requires frequent monitoring and is complicated by drug-drug interactions and the need to maintain a narrow therapeutic window. Since 2009, novel oral anticoagulants (NOACs), including the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors apixaban, edoxaban, and rivaroxaban, have become alternative options to VKAs owing to their predictable and safe pharmacological profiles. The overall clinical effect of these drugs, which is a balance between ischaemic benefit and bleeding harm, varies according to the clinical scenario. As adjunctive therapy to dual antiplatelet therapy in patients with acute coronary syndrome, NOACs are associated with incremental bleeding risks and modest benefits. For treatment of VTE, NOACs have a safer profile than VKAs and a similar efficacy. In thromboprophylaxis in AF, NOACs are associated with the greatest benefits by reducing both ischaemic events and haemorrhagic complications and might reduce mortality compared with VKAs. The role of NOACs continues to evolve as these drugs are evaluated in different patient populations, including those with renal impairment or with AF and undergoing percutaneous coronary intervention.

Comparison of different approaches to atrioventricular junction ablation and pacemaker implantation in patients with atrial fibrillation

BACKGROUND

To compare the feasibility and efficiency of atrioventricular junction (AVJ) ablation and device implantation in patients with drug-refractory atrial fibrillation using three different approaches.

METHODS

Sixty-nine patients (57% male; age 72 ± 10; ejection fraction 45 ± 15%) undergoing device implantation and AVJ ablation were retrospectively studied at a tertiary referral center. In 20 patients (29%) AVJ ablation was performed via the femoral vein immediately following device implantation (group 1), whereas 33 patients (48%) underwent a staged procedure with AVJ ablation via the femoral vein >3 weeks after device implantation (group 2). In a third group of 16 patients (23%), AVJ ablation was performed during device implantation through the pocket using the same axillary vein access site (group 3). The main outcome measures were: procedure time, fluoroscopy time, laboratory occupancy time, and success rate.

RESULTS

There was a significant difference in procedure time (118 ± 45 minutes. in group 1, 133 ± 32 minutes in group 2, and 87 ± 26 minutes in group 3, P < 0.001) and the laboratory occupancy time (175 ± 48 minutes in group 1, 200 ± 32 minutes in group 2, and 121 ± 27 minutes in group 3, P < 0.001). There was no difference in fluoroscopy time (group 1: 20 ± 15 minutes, group 2: 27 ± 22 minutes, and group 3: 24 ± 9 minutes P = 0.4). The procedure was successfully completed in all patients, but cross-over to a femoral approach was required in one patient in group 3.

CONCLUSION

The alternative approach of AVJ ablation during permanent pacemaker implantation from the same axillary vein access site is feasible and more efficient compared to the femoral approach.

Predictors of long-term maintenance of normal sinus rhythm after successful electrical cardioversion

Electrical cardioversion (EC) for atrial fibrillation (AF) is a common procedure performed in an attempt to restore normal sinus rhythm (NSR). Many factors predict long-term maintenance of NSR and the risk of AF recurrence. The duration of AF, cardiac size and function, rheumatic heart disease, significant mitral valve disease, left atrial enlargement, and older age are among the most common recognized factors. A number of interventions can potentially decrease the AF recurrence rate. Identifying and treating reversible causes and the use of antiarrhythmic medications in certain situations can help decrease the risk of AF recurrence. The role of the newer anticoagulants is expanding, and wider application is expected in the near future. We hope that this summary will serve as a guide to physicians and healthcare providers to address the question of who should undergo cardioversion, as there are patients who are most likely to benefit from this procedure and others that will revert back into AF within a short period. To identify who would benefit most from EC and have a reasonable chance of long-term maintenance of NSR, a thorough evaluation of each individual patient should be performed to tailor the best therapy to each individual.

Antithrombotic effects of losartan in patients with hypertension complicated by atrial fibrillation: 4A (Angiotensin II Antagonist of platelet Aggregation in patients with Atrial fibrillation), a pilot study

Angiotensin receptor blockers (ARBs) are widely used for the treatment of hypertension. It has been reported that the ARB losartan has antiplatelet, anticoagulant and profibrinolytic effects experimentally. These properties could be desirable to treat hypertensive patients with high atherothrombotic and/or thromboembolic risk. To examine the antithrombotic effects of losartan in hypertension, 20 consecutive patients with hypertension complicated by atrial fibrillation (AF) were enrolled in this study. The patients were treated with losartan 50 mg for 8 weeks followed by 100 mg for 4 weeks. Blood samples were obtained from each patient at 0 (pretreatment), 8 and 12 weeks after initiating treatment. Platelet aggregability, plasma levels of tissue factor (TF) and type 1 plasminogen activator inhibitor (PAI-1) activity levels were measured. The area under the curve for small platelet aggregability decreased from 100 to 42.8% at 12 weeks (P<0.0001). TF levels (ng ml(-1)) and PAI-1 activity (IU ml(-1); mean±s.d.) also changed from 14.2±3.6 to 10.9±4.5 at 12 weeks (P=0.0299) and from 11.7±3.6 to 8.5±3.1 at 12 weeks (P=0.0122), respectively. Losartan inhibited platelet activity and coagulation factors in a dose- and time-dependent manner in patients with hypertension complicated by AF, whereas the fibrinolytic capacity was increased. The use of losartan could be advantageous in the treatment of hypertensive patients with high atherothrombotic risk.

Comparison of transesophageal echocardiography versus computed tomography for detection of left atrial appendage filling defect (thrombus)

Patients with atrial fibrillation, who are referred for radiofrequency pulmonary vein antral isolation, frequently undergo transesophageal echocardiography (TEE) to detect and/or exclude left atrial or left atrial appendage (LAA) thrombus and cardiac computed tomographic angiography (CCTA) to define and/or evaluate left atrial and pulmonary venous anatomy. Previous studies have reported CCTA to have high sensitivity and negative predictive value (NPV) for detecting thrombus in the LAA. Previous studies determining an optimal LAA/ascending aorta (AA) Hounsfield unit (HU) density ratio for detection of LAA thrombus have been small, with limited numbers of thrombi. We thus sought to determine both the optimal cutoff for LAA HU density and LAA/AA HU density ratio in detecting LAA thrombus compared with TEE in a multicenter population. We included 84 patients who had undergone CCTA and TEE. LAA was evaluated by 64-row CCTA qualitatively (visual filling defect) and quantitatively (measurement of LAA HU density and LAA/AA HU density ratio), using a 1-cm area of interest in the same axial plane. Results were compared with TEE visualization of thrombus or spontaneous echo contrast. Qualitative identification of thrombus in LAA by CCTA compared with TEE detection of thrombus had a sensitivity of 100%, a specificity of 77.9%, a positive predictive value (PPV) of 51.6%, an NPV of 100%, and a total accuracy of 82.1%. The optimal LAA HU density cutoff for thrombus detection was 119 with a sensitivity of 88%, a specificity of 86%, PPV 56%, and an area under the curve of 0.923 (p = 0.0004). The optimal LAA/aorta HU ratio was 0.242 with a sensitivity of 87%, a specificity of 88%, a PPV of 64%, and an area under the curve of 0.921 (p = 0.0011). There is no significant difference (p = 0.72) between both areas under the curve, and both measurements improved the specificity and PPV compared with qualitative measures. Multidetector computed tomography is an imaging technique that can exclude LAA thrombus with very high NPV. Quantitative measurement of LAA HU density (cutoff 119) or LAA/aorta HU density ratio (cutoff 0.242) improves accuracy of positively detecting LAA thrombus. This technique is especially useful when delayed scanning is not performed and LAA is found incidentally after the patient scanning is complete.

The preventive effect of statin therapy on new-onset and recurrent atrial fibrillation in patients not undergoing invasive cardiac interventions: a systematic review and meta-analysis

BACKGROUND

Previous meta-analyses suggest that pre-procedural use of statin therapy may reduce atrial fibrillation (AF) following invasive cardiac interventions (coronary artery by-pass grafting and percutaneous coronary intervention). However, the current evidence on the benefit of statins unrelated to invasive cardiac interventions has not been clarified systematically.

METHODS

Through a systematic literature search, trials examining the effect of statin therapy on AF were selected. Trials using statins before any percutaneous or surgical cardiac interventions were excluded.

RESULTS

The search identified 11 randomized and 16 observational eligible studies, totaling 106,640 patients receiving statin therapy and 129,305 serving as controls. Fourteen studies investigated the effect of statins on new-onset AF, 13 studies investigated the effect of statins on recurrent AF and one in both new-onset and recurrent AF. In the statin versus control group the mean age was 60.7 ± 8.3 versus 68.6 ± 6.2 years and females comprised 8.4% versus 10.3%. Statin therapy was associated with significant reduction of AF (Risk ratio (RR): 0.81 [95% confidence interval (CI): 0.80-0.83], p<0.001) combining all studies. Assessing exclusively randomized trials, statin therapy showed no significant risk reduction (RR: 0.97 [95%CI: 0.90-1.05], p=0.509), heterogeneity p>0.05. Assessing exclusively observational studies the risk reduction of new-onset AF was 12% (RR: 0.88 [95%CI: 0.85-0.91], p<0.001) and recurrent AF 15% (RR: 0.85 [95%CI: 0.80-0.90], p<0.001), heterogeneity p<0.001.

CONCLUSION

The hitherto published randomized clinical trials do not support a beneficial effect of statins on AF in patients not undergoing invasive cardiac interventions. This is in contrast to the results of observational and interventional studies.

Spontaneous normal sinus rhythm conversion using integrative medicine in atrial fibrillation

The relationship between acute life stress and the development of atrial fibrillation (AF) has been noted in the literature. However, the use of integrative medicine (IM) in restoring cardiac rhythm has not been adequately studied. This case report describes how an IM approach was used in a patient with atrial fibrillation and acute pain. Spontaneous cardioversion to normal sinus rhythm occurred during the IM session, in addition to marked decreases in self-reported pain, anxiety, and nausea at the conclusion of IM treatment. These results provide initial support that for some cases of AF, IM therapies can help to reduce costs via avoidance of additional hospitalization, electrocardioversion, and general anesthesia.

Effect of lipid lowering on new-onset atrial fibrillation in patients with asymptomatic aortic stenosis: the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study

BACKGROUND

Lipid-lowering drugs, particularly statins, have anti-inflammatory and antioxidant properties that may prevent atrial fibrillation (AF). This effect has not been investigated on new-onset AF in asymptomatic patients with aortic stenosis (AS).

METHODS

Asymptomatic patients with mild-to-moderate AS (n = 1,421) were randomized (1:1) to double-blind simvastatin 40 mg and ezetimibe 10 mg combination or placebo and followed up for a mean of 4.3 years. The primary end point was the time to new-onset AF adjudicated by 12-lead electrocardiogram at a core laboratory reading center. Secondary outcomes were the correlates of new-onset AF with nonfatal nonhemorrhagic stroke and a combined end point of AS-related events.

RESULTS

During the course of the study, new-onset AF was detected in 85 (6%) patients (14.2/1,000 person-years of follow-up). At baseline, patients who developed AF were, compared with those remaining in sinus rhythm, older and had a higher left ventricular mass index a smaller aortic valve area index. Treatment with simvastatin and ezetimibe was not associated with less new-onset AF (odds ratio 0.89 [95% CI 0.57-1.97], P = .717). In contrast, age (hazard ratio [HR] 1.07 [95% CI 1.05-1.10], P < .001) and left ventricular mass index (HR 1.01 [95% CI 1.01-1.02], P < .001) were independent predictors of new-onset AF. The occurrence of new-onset AF was independently associated with 2-fold higher risk of AS-related outcomes (HR 1.65 [95% CI 1.02-2.66], P = .04) and 4-fold higher risk of nonfatal nonhemorrhagic stroke (HR 4.04 [95% CI 1.18-13.82], P = .03).

CONCLUSIONS

Simvastatin and ezetimibe were not associated with less new-onset AF. Older age and greater left ventricular mass index were independent predictors of AF development. New-onset AF was associated with a worsening of prognosis.

Combined Bipolar/Unipolar Radiofrequency Maze is Superior to Unipolar Maze in Concomitant Surgery

Introduction:

Atrial fibrillation is the most common arrhythmia with significant morbidity and mortality. Radiofrequency (RF) ablation, despite its shortcomings, remain an acceptable and ‘simple’ technique.

Methods:

We reviewed 137 consecutive concomitant irrigated RF modified maze procedures, and compared the outcomes of 65 patients undergoing Unipolar-RF versus 72 patients using the combined Uni/Bipolar-RF approach. All patients were prospectively followed clinically, with serial electrocardiography and selective echocardiography. One hundred and twenty-two patients (89.1%) underwent mitral valve procedures, and eight coronary bypass, and seven adult congenital operations were performed.

Results:

The predominantly male (54.7%) patients had a mean age of 58.3±11.5 years (23–88 years). At median follow-up of 3.21 years (0.01–6.06 years), 15 (10.9%) patients were lost to follow-up. Freedom from AF in the Uni/Bipolar-RF group was higher at six months: 85.1% (57/67) versus 65% (39/60) in the Unipolar-RF group (P=0.012). This superior trend persisted at five years: 100% (5/5) in the Uni/Bipolar-RF group versus 79.5% (31/39) in the Unipolar-RF group, although this is not statistically significantly (P=0.566). Patients with left atrial dilatation beyond 7.6cm were more likely to remain in AF (OR 0.44, 95% CI, 0.19–1.00, P=0.049). Perioperative mortality was 2.9%. There was no collateral damage by the device and procedure. The mean survival for patients AF-free at last follow-up is 5.73 years (95% CI, 5.48–5.98), comparable to 5.58 years (95% CI, 5.07–6.10) in those remaining in AF. Thirty (22.6%) patients were completely off anti-arrhythmic medication while 36 (25.6%) were anticoagulant-free.

Conclusion:

The combined Uni/bipolar-RF modified bi-atrial Maze technique is simple, safe and superior to isolated Unipolar-RF ablation. Midterm results continue to support its use although long-term durability remains to be elucidated.

New-onset versus chronic atrial fibrillation in acute myocardial infarction: differences in short- and long-term follow-up

AIMS

Atrial fibrillation (AF) occurs commonly in patients with acute myocardial infarction (AMI) and has been established as a marker of adverse prognosis. There are only few clinical trials that investigate differences between new-onset and chronic AF in AMI. We hypothesize that chronic AF is associated with an increased rate of adverse short- and long-term outcomes.

METHODS AND RESULTS

In a single center study, over a period of 28 months, 375 consecutive patients with AMI were included [337 patients without AF (89.9%) and 38 with AF (10.1%)]. As much as 16 patients had new-onset AF (42.1%) and 22 had chronic AF (57.9%). Patients with severe coronary artery disease develop AF more often in AMI, and the existence of AF was associated with a poor prognosis. Compared to patients with new-onset AF, chronic AF was more frequently associated with advanced age (75 vs. 70 years, p not significant), reduced left ventricular ejection fraction (44.8 vs. 54.0%, p < 0.05) and NSTEMI (63.6 vs. 36.4%, p < 0.05). Only chronic AF resulted in increased in-hospital death (18.2 vs. 0.0%; p < 0.005) at the 2-year follow-up, 14 patients with AF died (63.6%), predominantly due to cardiovascular reasons.

CONCLUSION

Our results indicate that patients with chronic AF had a higher incidence of in-hospital death than those with new-onset AF or without. Chronic AF includes a group of older and sicker patients than their counterparts with new-onset AF. Understanding these findings may ultimately lead to better care of patients with this arrhythmia to prevent the development of the underlying atrial substrate in chronic AF patients and to improve their otherwise worse prognosis.

Short-term and long-term success of electrical cardioversion in atrial fibrillation in managed care system

Background

Initial success of electrical cardioversion (ECV) of atrial fibrillation (AF) has been reported in several studies as 50%-90%, of which only 50% patients remain in sinus rhythm (SR) at the end of one year. We conducted this study to see if outcomes of other trials are applicable in managed care setting.

Methods

We conducted a retrospective study in 370 consecutive patients who underwent ECV for AF. They were reviewed for initial outcome of ECV and recurrence of AF after a successful ECV, with and without prophylactic antiarrhythmic drugs.

Results

Initial success of ECV for AF was 65.7%. At one year, 47% remained in SR. AF for ≤ 3 months (p = 0.006) and pretreatment with antiarrhythmic drugs (p = 0.032) resulted in improved success. Predictors of recurrence were patients ≤ 65 years (p = 0.019), paroxysmal atrial fibrillation (PAF) (p = 0.0094) and alcohol consumption (p = 0.0074).

Conclusion

Shorter duration of AF, prophylactic antiarrhythmic drugs and serial ECVs improve outcome of ECV in AF. For younger patients with PAF and alcohol consumption, due to higher recurrence of AF, rate control or ablative therapy may be the preferred strategy.

Propafenone versus procainamide for conversion of atrial fibrillation to sinus rhythm

BACKGROUND AND HYPOTHESIS

Antiarrhythmic drugs are widely used for treatment of atrial fibrillation (AF) and restoration of sinus rhythm. This prospective, randomized, and controlled study compared the efficiency and safety of propafenone versus procainamide for the treatment of acute AF.

METHODS

In all, 117 patients (55 women, 62 men, mean age 64.2 +/- 13 years, median 63 years) who presented with AF were included in the study. Exclusion criteria were signs or symptoms of heart failure on physical examination, recent myocardial infarction or cardiac surgery, cardiogenic shock, or hypotension. Forty-one patients spontaneously recovered sinus rhythm; the remaining 76 patients were randomized to receive propafenone or procainamide. Propafenone was given at a dose of 2 mg/kg body weight intravenously (i.v.) over 30 min. Patients randomized to receive procainamide received a bolus of 100 mg i.v. administered every 5 min up to a maximum dose of 1 g. The clinical characteristics of the two groups were comparable.

RESULTS

The number of patients who recovered sinus rhythm after the treatment was larger in the procainamide-treated group (Group 1) (69.5%) than in the propafenone-treated group (Group 2) (48.7%); p < 0.05. The time required for cardioversion was significantly lower in Group 1 (mean 4.1 +/- 1.3 h), than in Group 2 patients (mean 7.3 +/- 2.6 h) (p < 0.01).

CONCLUSION

In the present study, procainamide was more effective than propafenone for the treatment of AF of short duration.

Association between serum C-reactive protein elevation and atrial fibrillation after first anterior myocardial infarction

BACKGROUND

Elevated inflammatory markers have been found to correlate with higher risk for cardiac events in patients with acute myocardial infarction (AMI). It has been suggested that C-reactive protein (CRP) may be involved in the initiation process of atrial fibrillation (AF). However, the role of CRP levels in the occurence of AF in patients with AMI has not been studied. This study investigated whether CRP is a risk factor for AF in patients with acute anterior MI.

METHODS

We prospectively evaluated 92 consecutive patients (25 women and 67 men; aged 58 +/- 11 y) with a first acute anterior wall MI. Blood samples were obtained at the time of admission to the hospital, and serum CRP levels were measured by an ultrasensitive immunonephelometry method. All patients were evaluated by echocardiography to measure the left ventricular (LV) diameter and functions. All patients were monitored continuously for the detection of AF in the coronary care unit.

RESULTS

Atrial fibrillation occured in 19 (20%) of 92 patients. Univariate analysis showed that patients with AF had an advanced age (63 +/- 9.9 versus 56.7 +/- 11.7 y, p = 0.034), higher serum CRP level (2.95 +/- 2.5 versus 1.71 +/- 2.12 mg/dL, p = 0.034), larger LV end-systolic volume (74 +/- 15 versus 63 +/- 19, mL p = 0.02), higher LV ejection fraction (31.1 +/- 6.2 versus 38.4 +/- 10%, p = 0.001), and larger left atrial (LA) diameter (37.1 +/- 4.2 versus 34.7 +/- 3.3 mm, p = 0.01). In multivariate analysis, only age (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1-1.11, p = 0.036) and CRP levels (OR: 1.27, 95% CI: 1-1.59, p = 0.039) were independent predictors of AF.

CONCLUSION

These results suggest that CRP may be a risk factor for AF in patients with acute anterior wall MI.

A comparative study of the efficacy and safety of procainamide versus propafenone versus amiodarone for the conversion of recent-onset atrial fibrillation

The appropriate treatment for the restoration of sinus rhythm in patients with atrial fibrillation (AF) of recent onset is still the subject of controversy. In this prospective, randomized, single-blind, placebo-controlled clinical study, we investigated the effectiveness and safety of procainamide, propafenone, and amiodarone, administered intravenously, for the conversion of recent-onset AF. We enrolled 362 consecutive patients (183 men; age 34 to 86 years; mean 65+/-10) with AF duration of no >48 hours. Of these patients, 89 were given procainamide, 91 propafenone, 92 amiodarone, and 90 placebo. Treatment was considered successful if conversion to sinus rhythm was achieved within the 24-hour study period. Baseline clinical characteristics were similar in the 4 groups. The treatment was successful in 61 of the 89 patients who received procainamide (68.53%; median time 3 hours), 73 of the 91 patients who received propafenone (80.21%; median time 1 hour), 82 of the 92 patients who received amiodarone (89.13%; median time 9 hours), and 55 of the 90 patients who received placebo (61.11%; median time 17 hours; p<0.05 for all medicated groups vs placebo; p<0.05 for amiodarone and propafenone vs procainamide). In conclusion, all 3 medications, when administered intravenously, are effective in the restoration of sinus rhythm in recent-onset AF. Amiodarone and propafenone are more effective whereas procainamide and propafenone are faster.

Intravenous amiodarone for cardioversion of recent-onset atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is one of the most common causes of hospital admission, with a prevalence of up to 5% of the population, increasing with advancing age. Emergency direct current cardioversion is the therapy of choice when arrhythmia leads to hemodynamic compromise, but in patients who are hemodynamically stable, antiarrhythmic drugs are usually given to restore sinus rhythm.

HYPOTHESIS

The study was undertaken to assess the efficacy of intravenous amiodarone in cardioversion of recent-onset paroxysmal atrial fibrillation (AF). No standard antiarrhythmic therapy has been accepted for pharmacologic cardioversion of AF. Amiodarone seems to be a promising candidate, but only few randomized trials are available and the results are inconsistent.

METHODS

In all, 160 patients with AF lasting < 24 h were randomly assigned (2:1 fashion) to the amiodarone group (n = 106) receiving 5 mg/kg as a 30 min intravenous (i.v.) infusion, followed by i.v. infusion of 10 mg/kg during 20 h diluted in 1000 ml of 10% glucose with 20 IU of rapid-action insulin, 80 mEq of potassium chloride, and 8 g of magnesium sulphate (GIKM), or to the control group (n = 54) receiving 1000 ml of GIKM alone. Treatment was continued up to 20 h independent of sinus rhythm restoration.

RESULTS

Sinus rhythm was restored 20 h after initiation of therapy in 88 (83%) patients in the amiodarone group and in 24 (44%) patients in the control group (p < 0.0001). The difference between efficacy of the two treatment modalities became significant already after 8 h of therapy (53 vs. 14 patients with sinus rhythm, respectively, p < 0.05). The mean dose of amiodarone administered until sinus rhythm restoration was 740 +/- 296 mg. The presence and the type of underlying heart disease did not influence the conversion rate in either group. In two patients (1.8%) treated with amiodarone, the return of sinus rhythm was preceded by asystole.

CONCLUSION

Amiodarone is effective in the termination of AF lasting < 24 h. It may be particularly useful in patients with organic heart disease in whom class I antiarrhythmic agents may be contraindicated. During treatment, the heart rhythm should be monitored continuously.

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

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

Echocardiography in atrial fibrillation

Atrial fibrillation is the most commonly encountered sustained arrhythmia. Echocardiography has augmented the knowledge about etiology and complications of atrial fibrillation. Transthoracic echocardiography allows rapid, safe and comprehensive assessment of cardiac structure and function, and is recommended for all subjects with atrial fibrillation. The use of transesophageal echocardiography has contributed to a better understanding of the thromboembolic risk in patients with atrial fibrillation, especially in the setting of electrical cardioversion. Several investigators have demonstrated the feasibility and safety profile of early cardioversion with short-term anticoagulation in patients with atrial fibrillation and a transesophageal echocardiography negative for atrial thrombi. More recently, transesophageal and intracardiac echocardiography have been employed in patients with atrial fibrillation to monitor percutaneous procedures such as pulmonary veins radiofrequency ablation or left atrial appendage obliteration. In this review the available echocardiographic imaging modalities and their specific role in the evaluation and management in atrial fibrillation are described.

Ibutilide to expedite ED therapy for recent-onset atrial fibrillation flutter

OBJECTIVE

Ibutilide is a type III antiarrhythmic agent approved for the pharmacologic conversion of atrial fibrillation (AF) and atrial flutter (AFl). Previous studies conducted outside the ED setting have demonstrated conversion rates of 60% to 80%. This response has been highest in patients with recent-onset AF-AFl. These observations and the 4-hour half-life of ibutilide suggest that it may be an excellent drug with which to treat AF-AFl in the ED. The purpose of the study was to examine the efficacy and safety of ibutilide in terminating AF-AFl in patients who present to the ED with symptoms of less than 3 days' duration, neither angina nor heart failure, and no comorbid conditions that require admission.

METHODS

Among 36 enrolled patients, the admission electrocardiogram demonstrated AF in 26 and AFl in 10. Ibutilide 1 mg was administered intravenously for 10 minutes. If sinus rhythm was not present 10 minutes after the infusion concluded, a second infusion of 1 mg was given. Successful conversion was defined as restoration of sinus rhythm within 1 hour after the last dose of ibutilide.

RESULTS

Sixteen (61.5%) of 26 patients with AF and 9 (90%) of 10 patients with AFl converted to sinus rhythm (overall conversion rate=69%). The mean time to arrhythmia termination was 19+/-9 minutes. The mean stay in the ED was 16.2 hours. No significant complications occurred.

CONCLUSION

We conclude that ibutilide is an excellent therapy option for restoring sinus rhythm in the ED. Its use may obviate the need for admission, avoid the risks and inconveniences of general anesthesia to perform electrical cardioversion, and reduce the ED length of stay in selected patients with recent-onset atrial arrhythmias.

A randomized trial of prophylactic antiarrhythmic agents (amiodarone and sotalol) in patients with atrial fibrillation for whom direct current cardioversion is planned

Antiarrhythmic agents enhance maintenance of sinus rhythm (SR) after direct current cardioversion (DCC) for atrial fibrillation but there are few comparative trials.

BACKGROUND

The aims of the study were (1) to establish whether patients successfully cardioverted to SR are more likely to stay in SR over 6 months if taking amiodarone or sotalol, and if so, to establish whether one agent is better than the other; (2) to establish whether taking amiodarone or sotalol is better at achieving chemical cardioversion within the 6 weeks before DCC; and (3) to establish whether DCC is more likely to be successful on a drug.

METHODS

Randomized, prospective, nonblinded, controlled study of treatment with either amiodarone (n = 27), sotalol (n = 36), or no antiarrhythmic agent (n = 31).

RESULTS

Chemical cardioversion occurred in 7 patients in the amiodarone group (A), 7 patients in the sotalol group (S), but none in the no-antiarrhythmic group (N). A total of 33 (92%) patients in the sotalol group, 22 (81%) patients in the amiodarone group, and 23 (74%) patients in the no-antiarrhythmic group were in SR after cardioversion. Of the original cohort of patients, 17 (63%) patients in the amiodarone group remained in SR at 6-month follow-up, compared with 14 (39%) in the sotalol group and 5 (16%) in the no-antiarrhythmic group (A vs N, P < .0002, P < .0006B [after Bonferroni correction]; A vs S, P = .05, P = .15B; and S vs N, P = .03, P = .09B).

CONCLUSIONS

Amiodarone and sotalol achieved chemical cardioversion before planned electrical cardioversion in 26% and 19% of patients, respectively. After successful cardioversion, amiodarone appears better than sotalol at maintaining SR at 6 months.