Management Of New-onset Atrial Fibrillation Research Articles

An International Survey of the Management of Atrial Fibrillation in Critically Unwell Patients.

To evaluate the current management of new-onset atrial fibrillation and compare differences in practice regionally. Cross-sectional survey. United States, Canada, United Kingdom, Europe, Australia, and New Zealand. Critical care attending physicians/consultants and fellows. None. A total of 386 surveys were included in our analysis. Rate control was the preferred treatment approach for hemodynamically stable patients (69.1%), and amiodarone was the most used antiarrhythmic medication (70.9%). For hemodynamically unstable patients, a strategy of electrolyte supplementation and antiarrhythmic therapy was most common (54.7%). Physicians responding to the survey distributed by the Society of Critical Care Medicine were more likely to prescribe beta-blockers as a first-line antiarrhythmic medication (38.4%), use more transthoracic echocardiography than respondents from other regions (82.4%), and more likely to refer patients who survive their ICU stay for cardiology follow-up if they had new-onset atrial fibrillation (57.2%). The majority of survey respondents (83.0%) were interested in participating in future studies of atrial fibrillation in critically ill patients. Significant variation exists in the management of new-onset atrial fibrillation in critically ill patients, as well as geographic variation. Further research is necessary to inform guidelines in this population and establish if differences in practice impact long-term outcomes.

New-onset atrial fibrillation among COVID-19 patients: A narrative review.

Over the last three years, research has focused on examining cardiac issues arising from coronavirus disease 2019 (COVID-19) infection, including the emergence of new-onset atrial fibrillation (NOAF). Still, no clinical study was conducted on the persistence of this arrhythmia after COVID-19 recovery. Our objective was to compose a narrative review that investigates COVID-19-associated NOAF, emphasizing the evolving pathophysiological mechanisms akin to those suggested for sustaining AF. Given the distinct strategies involved in the persistence of atrial AF and the crucial burden of persistent AF, we aim to underscore the importance of extended follow-up for COVID-19-associated NOAF. A comprehensive search was conducted for articles published between December 2019 and February 11, 2023, focusing on similarities in the pathophysiology of NOAF after COVID-19 and those persisting AF. Also, the latest data on incidence, morbidity-mortality, and management of NOAF in COVID-19 were investigated. Considerable overlaps between the mechanisms of emerging NOAF after COVID-19 infection and persistent AF were observed, mostly involving reactive oxygen pathways. With potential atrial remodeling associated with NOAF in COVID-19 patients, this group of patients might benefit from long-term follow-up and different management. Future cohort studies could help determine long-term outcomes of NOAF after COVID-19.

New-Onset Atrial Fibrillation in the Critically Ill COVID-19 Patients Hospitalized in the Intensive Care Unit.

New-onset atrial fibrillation (NOAF) is the most frequently encountered cardiac arrhythmia observed in patients with COVID-19 infection, particularly in Intensive Care Unit (ICU) patients. The purpose of the present review is to delve into the occurrence of NOAF in COVID-19 and thoroughly review recent, pertinent data. However, the causality behind this connection has yet to be thoroughly explored. The proposed mechanisms that could contribute to the development of AF in these patients include myocardial damage resulting from direct virus-induced cardiac injury, potentially leading to perimyocarditis; a cytokine crisis and heightened inflammatory response; hypoxemia due to acute respiratory distress; disturbances in acid-base and electrolyte levels; as well as the frequent use of adrenergic drugs in critically ill patients. Additionally, secondary bacterial sepsis and septic shock have been suggested as primary causes of NOAF in ICU patients. This notion gains strength from the observation of a similar prevalence of NOAF in septic non-COVID ICU patients with ARDS. It is plausible that both myocardial involvement from SARS-CoV-2 and secondary sepsis play pivotal roles in the onset of arrhythmia in ICU patients. Nonetheless, there exists a significant variation in the prevalence of NOAF among studies focused on severe COVID-19 cases with ARDS. This discrepancy could be attributed to the inclusion of mixed populations with varying degrees of illness severity, encompassing not only patients in general wards but also those admitted to the ICU, whether intubated or not. Furthermore, the occurrence of NOAF is linked to increased morbidity and mortality. However, it remains to be determined whether NOAF independently influences outcomes in critically ill COVID-19 ICU patients or if it merely reflects the disease's severity. Lastly, the management of NOAF in these patients has not been extensively studied. Nevertheless, the current guidelines for NOAF in non-COVID ICU patients appear to be effective, while accounting for the specific drugs used in COVID-19 treatment that may prolong the QT interval (although drugs like lopinavir/ritonavir, hydrochlorothiazide, and azithromycin have been discontinued) or induce bradycardia (e.g., remdesivir).

New Onset Atrial Fibrillation in STEMI Patients: Main Prognostic Factors and Clinical Outcome.

The indications for the treatment of patients with known atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) are clear, while less is available about the management of new-onset AF (NOAF) during ST-segment elevation myocardial infarction (STEMI). The aim of this study is to evaluate mortality and clinical outcome of this high-risk subgroup of patients. We analyzed 1455 consecutive patients undergoing PCI for STEMI. NOAF was detected in 102 subjects, 62.7% males, with a mean age of 74.8 ± 10.6 years. The mean ejection fraction (EF) was 43.5 ± 12.1% and the mean atrial volume was increased (58 ± 20.9 mL). NOAF occurred mainly in the peri-acute phase and had a very variable duration (8.1 ± 12.5 min). During hospitalization, all the patients were treated with enoxaparin, but only 21.6% of them were discharged with long term oral anticoagulation. The majority of patients had a CHA2DS2-VASc score >2 and a HAS-BLED score of 2 or 3. The in-hospital mortality was 14.2%, while the 1-year mortality was 17.2% and long-term mortality 32.1% (median follow-up 1820 days). We identified age as an independent predictor of mortality both at short- and long-term follow-ups, while EF was the only independent predictor for in-hospital mortality and arrhythmia duration for 1-year mortality. At the 1-year follow-up, we recorded three ischemic strokes and no bleeding complications.

130: CALCIUM CHANNEL BLOCKERS VERSUS BETA BLOCKERS FOR ACUTE RATE CONTROL IN HEART FAILURE PATIENTS

Introduction: A rate control strategy is often pursued for management of new-onset atrial fibrillation and a rapid ventricular rate (RVR) in heart failure with reduced ejection fraction (HFrEF) patients. Either a beta blocker (BB) or non-dihydropyridine calcium channel blocker (non-DHP CCB) can be used, however, non-DHP CCBs may worsen heart failure through negative inotropic effects. This study was conducted to compare short-term use of BBs with non-DHP CCBs on the incidence of heart failure exacerbation. Methods: This was a multi-site, retrospective cohort study conducted at a 2,247-bed community teaching hospital system in the United States. Adult patients presenting to the emergency department for atrial fibrillation with RVR were included if they had new-onset or a history of HFrEF and received a non-DHP CCB or BB for less than 48 hours. Hemodynamically unstable patients were excluded. The primary outcome was the incidence of heart failure exacerbation within 48 hours of drug administration, defined by a combination of provider documentation and at least one clinical or laboratory marker. Additional efficacy and safety endpoints were assessed secondarily. Results: Between March 2018 and January 2021, 1,519 patients were screened and 164 included (113 in the non-DHP CCB group and 51 in the BB group). The median age was 70 years and 70% were male. The median dose of non-DHP CCB at 48 hours was 90 mg and the median duration was 13 hours. In the BB group, the median dose and duration was 5 mg and 6 hours, respectively. Eleven patients receiving a non-DHP CCB and 1 patient receiving a BB met the primary outcome (p=0.08). Patients who had a heart failure exacerbation in the non-DHP CCB group received both a higher median dose (190 mg) and longer median duration (21 hours) of therapy. Additionally, 6 patients in the non-DHP CCB group and 1 in the BB group experienced an exacerbation within 7 days (p=0.33). More patients in the non-DHP CCB group experienced bradycardia (23% vs 5.9%, p=0.008), however, there were no other differences in safety or efficacy. Conclusions: While not statistically significant, there were numerically more incidences of heart failure exacerbations in HFrEF patients receiving non-DHP CCBs compared with BBs for acute rate control.

Promising Therapies for Atrial Fibrillation and Ventricular Tachycardia.

Sudden cardiac death due to arrhythmias, such as atrial fibrillation or ventricular tachycardia, account for 15–20% of all deaths. Myocardial infarction increases the burden of atrial fibrillation and ventricular tachycardia by structural and electrical remodeling of the heart. The current management of new-onset atrial fibrillation includes electric cardioversion with very high conversion rates and pharmacologic cardioversion, with less a than 50% conversion rate. If atrial fibrillation cannot be converted, the focus becomes the control of the symptoms ensuring a constant rhythm and rate control, without considering other contributory factors such as autonomic imbalance. Recently, a huge success was obtained by developing ablation techniques or addressing the vagal nerve stimulation. On the other hand, ventricular tachycardia is more sensitive to drug therapies. However, in cases of non-responsiveness to drugs, the usual therapeutic choice is represented by stereotactic ablative therapy or catheter ablation. This review focuses on these newly developed strategies for treatment of arrhythmias in clinical practice, specifically on vernakalant and low-level tragus stimulation for atrial fibrillation and stereotactic ablative therapy for drug-refractory ventricular tachycardia. These therapies are important for the significant improvement of the management of atrial fibrillation and ventricular tachycardia, providing: (1) a safer profile than current therapies, (2) higher success rate than current solutions, (3) low cost of delivery.

Clinical Management of New-Onset Atrial Fibrillation in COVID-19 Patients Referred to a Tertiary Cardiac Arrhythmia Center after Hospital Discharge.

Background: Available reports on the post-discharge management of atrial fibrillation (AF) in COVID-19 patients are scarce. The aim of this case series was to describe the clinical outcomes of new-onset AF in COVID-19 patients referred to a tertiary cardiac arrhythmia center after hospital discharge. Methods: All consecutive patients referred to our center for an ambulatory evaluation from 18 May 2020 to 15 March 2022 were retrospectively screened. Patients were included in the current analysis if new-onset AF was diagnosed during hospitalization for COVID-19 and then referred to our clinic. Results: Among 946 patients, 23 (2.4%) were evaluated for new-onset AF during COVID-19. The mean age of the study cohort was 71.5 ± 8.1 years; 87.0% were male. Median time from COVID-19 discharge and the first ambulatory evaluation was 53 (41.5–127) days; median follow-up time was 175 (83–336) days. At the in-office evaluation, 14 (60.9%) patients were in sinus rhythm, and nine patients were in AF. In 13.0% of cases, oral anticoagulation was stopped according to CHADS-VASc. Eight patients in AF were scheduled for electrical cardioversion; one patient was rate-controlled. Four patients were treated with catheter ablation (CA) during follow-up. Two post-cardioversion AF recurrences were detected during follow-up, while no recurrences were diagnosed among patients who underwent CA. Conclusion: Our data suggest that AF may not be considered as a simple bystander of the in-hospital COVID-19 course. Management of new-onset AF in post-COVID-19 patients referred to our clinic did not significantly differ from our usual practice, both in terms of long-term oral anticoagulation and in terms of rhythm control strategy.

Treatments of new-onset atrial fibrillation in critically ill patients: a systematic review with meta-analysis.

New-onset atrial fibrillation (NOAF) is common in hospitalised patients with critical illness and associated with worse outcomes. Several interventions are available in the management of NOAF, but the overall effectiveness and safety of these interventions compared with placebo or no treatment are unknown. We conducted a systematic review with meta-analysis and trial sequential analysis (TSA) of randomised clinical trials (RCT) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses, the Cochrane Collaboration, and Grading of Recommendations Assessment, Development and Evaluation statements. We searched RCTs assessing any pharmacological and non-pharmacological treatment compared with placebo or no treatment in critically ill hospitalised patients with NOAF. The primary outcomes were all-cause mortality, adverse events, and health-related quality of life. We included 16 trials (n=1891) evaluating seven interventions. All trials were adjudicated 'some concerns' or 'high risk' of bias. The evidence is very uncertain for mortality (RR 0.53, 95% CI 0.03-8.30), adverse events (RR 1.28, 95% CI 0.85-1.92), and treatment efficacy i.e. rhythm control (RR 1.54, 95% CI 1.20-1.97; TSA-adjusted CI 0.56-4.53) between pharmacological treatment and placebo/no treatment (very low certainty evidence). There were no data for health-related quality of life or most of our secondary outcomes. The existing data are insufficient to firmly conclude on effects of any intervention against NOAF on any outcome in hospitalised patients with critical illness. Randomised trials of the most frequently used interventions against NOAF are warranted in these patients.

Pharmacological and non-pharmacological treatments and outcomes for new-onset atrial fibrillation in ICU patients: the CAFE scoping review and database analyses.

Pharmacological and non-pharmacological treatments and outcomes for new-onset atrial fibrillation in ICU patients: the CAFE scoping review and database analyses.

Treatment strategies for new-onset atrial fibrillation in critically ill patients: Protocol for a systematic review.

New-onset atrial fibrillation is frequent in critically ill patients and associated with poorer outcomes in these patients. Numerous interventions are used for the management of new-onset atrial fibrillation, but it is unknown if these interventions improve patient-important outcomes as compared with placebo or no active intervention in adult critically ill patients. We will conduct a systematic review with meta-analysis and trial sequential analysis of randomized clinical trials assessing pharmacological and non-pharmacological interventions of new-onset atrial fibrillation as compared with placebo or no active intervention in adult critically ill patients. The primary outcomes are mortality, adverse events and health-related quality of life. We will search the following databases: MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov, Science Citation Index and BIOSIS and follow the recommendations by the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We will evaluate the overall certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. New-onset atrial fibrillation is common in adult critically ill patients. However, the balance between the desirable and undesirable effects of pharmacological and non-pharmacological interventions is unknown. The outlined systematic review aims to provide updated data on this topic. Submitted to PROSPERO (CRD42020187178 ). Status: accepted.

New-onset atrial fibrillation and outcomes following isolated coronary artery bypass surgery: A systematic review and meta-analysis.

Prior meta‐analyses have shown that new‐onset atrial fibrillation (NOAF) occurs in up to 40% of patients following cardiac surgery and is associated with substantial major adverse cardiovascular events. The stroke and mortality implications of NOAF in isolated CABG without concomitant valve surgery is not known. We thought that NOAF would be associated with increased risk of stroke and mortality, even in patients undergoing isolated CABG. A blinded review of studies from MEDLINE, CENTRAL, and Web of Science was done by two independent investigators. Stroke, 30‐day/hospital mortality, long‐term cardiovascular mortality, and long‐term (>1 year) all‐cause mortality were analyzed. We used Review Manager Version 5.3 to perform pooled analysis of outcomes. Of 4461 studies identified, 19 studies (n = 129 628) met inclusion criteria. NOAF incidence ranged from 15% to 36%. NOAF was associated with increased risk of stroke (unadjusted OR 2.15 [1.82, 2.53] [P < .00001]; adjusted OR 1.88 [1.02, 3.46] [P = .04]). NOAF was associated with increased 30‐day/hospital mortality (OR 2.35 [1.67, 3.32] [P < .00001]) and long‐term cardiovascular mortality (OR 2.04 [1.35, 3.09] [P = .0007]) NOAF was associated with increased long‐term all‐cause mortality (unadjusted OR 1.79 [1.63, 1.96] [P < .00001]; adjusted OR 1.58 [1.24, 2.00] [P = .0002]). We found that the incidence of NOAF following isolated CABG is high and is associated with increased stroke rate and mortality. Early recognition and management of NOAF could improve outcomes.

A Review of the Incidence and Management of New-Onset Atrial Fibrillation Post Transcatheter Aortic Valve Implantation

Transcatheter Aortic Valve Implantation (TAVI) is an established treatment option for patients with aortic stenosis who are considered highrisk for surgical valve replacement. New-onset atrial fibrillation (NOAF) is a serious adverse event post TAVI that is predictive of poor outcomes and whose pathophysiology remains unclear. The incidence of NOAF post-TAVI has a reportedly broad range depending on the study but has been correlated to procedure approach, choice of valve, and the use of general anesthesia. While surgical aortic valve replacement (SAVR) has traditionally been the preferred treatment for aortic stenosis, recent studies have demonstrated the benefits of expanding TAVI into a larger patient population. Additionally, the management of NOAF post-TAVI remains highly variable. This review paper aims to summarize the incidence of NOAF and to outline management strategies.

Clarifying the management of new-onset atrial fibrillation

In last month's issue, we published a clinical protocol for atrial fibrillation in acute settings by Munawar and Millward. Here, Michael Sampson presents a response to the article and aims to add context and clarity to some potentially misleading statements made in the original protocol

New-onset atrial fibrillation: an update.

New-onset atrial fibrillation (NOAF) is the most common perioperative complication of heart surgery, typically occurring in the perioperative period. NOAF commonly occurs in patients who are elderly, or have left atrial enlargement, or left ventricular hypertrophy. Various factors have been identified as being involved in the development of NOAF, and numerous approaches have been proposed for its prevention and treatment. Risk factors include diabetes, obesity, and metabolic syndrome. For prevention of NOAF, β-blockers and amiodarone are particularly effective and are recommended by guidelines. NOAF can be treated by rhythm/rate control, and antithrombotic therapy. Treatment is required in patients with decreased cardiac function, a heart rate exceeding 130beats/min, or persistent NOAF lasting for ≥ 48h. It is anticipated that anticoagulant therapies, as well as hemodynamic management, will also play a major role in the management of NOAF. When using warfarin as an anticoagulant, its dose should be adjusted based on PT-INR. PT-INR should be controlled between 2.0 and 3.0 in patients aged < 70years and between 1.6 and 2.6 in those aged ≥ 70years. Rate control combined with antithrombotic therapies for NOAF is expected to contribute to further advances in treatment and improvement of survival.

Current practice in the management of new-onset atrial fibrillation in critically ill patients: a UK-wide survey

BackgroundNew-onset atrial fibrillation (AF) is the most common arrhythmia in critically ill patients. Although evidence base and expert consensus opinion for management have been summarised in several international guidelines, no specific considerations for critically ill patients have been included. We aimed to establish current practice of management of critically ill patients with new-onset AF.MethodsWe designed a short user-friendly online questionnaire. All members of the Intensive Care Society were invited via email containing a link to the questionnaire, which comprised 21 questions. The online survey was conducted between November 2016 and December 2016.ResultsThe response rate was 397/3152 (12.6%). The majority of respondents (81.1%) worked in mixed Intensive Care Units and were consultants (71.8%). Most respondents (39.5%) would start intervention on patients with fast new-onset AF and stable blood pressure at a heart rate between 120 and 139 beats/min. However, 34.8% of participants would treat all patients who developed new-onset fast AF. Amiodarone and beta-blockers (80.9% and 11.6% of answers) were the most commonly used anti-arrhythmics. A total of 63.8% of respondents do not regularly anti-coagulate critically ill patients with new-onset fast AF, while 30.8% anti-coagulate within 72 hours. A total of 68.0% of survey respondents do not routinely use stroke risk scores in critically ill patients with new-onset AF. A total of 85.4% of participants would consider taking part in a clinical trial investigating treatment of new-onset fast AF in the critically ill.DiscussionOur results suggest a considerable disparity between contemporary practice of management of new-onset AF in critical illness and treatment recommendations for the general patient population suffering from AF, particularly with regard to anti-arrhythmics and anti-coagulation used. Amongst intensivists, there is a substantial interest in research for management of new-onset AF in critically ill patients.

Early Restoration of Atrial Contractility After New-Onset Atrial Fibrillation in Off-Pump Coronary Revascularization

Duration of anticoagulation therapy is one of the major concerns about management of new-onset atrial fibrillation (AF) after myocardial revascularization. We evaluated whether right and left atrial contractility was restored early after electrical sinus conversion in patients who experienced new-onset AF after off-pump coronary artery bypass grafting. From January 2009 to December 2010, 62 patients who underwent off-pump coronary artery bypass grafting and experienced new-onset AF were prospectively enrolled. Right and left atrial contractility was evaluated with transthoracic echocardiography performed 23 ± 10 hours after restoration of sinus rhythm. Anticoagulation was initiated when the AF continued for more than 24 hours. New-onset AF occurred at 2.3 ± 1.2 postoperative days, and continued or recurred for 26 ± 31 hours (>24 hours in 22 patients). Right and left atrial contractility was demonstrable after sinus conversion in all patients. Mitral inflow E and A wave velocities and the E/A ratio were 0.71 ± 0.21 m/s, 0.68 ± 0.19 m/s, and 1.15 ± 0.57, respectively. Mitral valve A' velocity was 7.9 ± 1.9 cm/s. Tricuspid inflow E and A wave velocities and E/A ratio were 0.52 ± 0.12 m/s, 0.42 ± 0.13 m/s, and 1.30 ± 0.27, respectively. There were no significant differences in echocardiographic data between patients who had AF lasting longer than 24 hours and those with AF lasting 24 hours or less. Anticoagulation was discontinued after demonstration of atrial contractility. No patients experienced bleeding complications during anticoagulation or thromboembolic events after cessation of anticoagulation. Short-term anticoagulation may be sufficient for the prevention of thromboembolic events in patients who underwent off-pump coronary artery bypass grafting and experienced new-onset AF because right and left atrial contractility was restored early after sinus conversion.

The significance of new onset atrial fibrillation complicating acute myocardial infarction

Atrial fibrillation (AF) in the setting of acute myocardial infarction (AMI) independently predicts in-hospital and long-term morbidity and mortality. Very little data exist regarding the prognostic significance and management of new-onset AF in this setting in the era of dual anti-platelet therapy. We identified all patients admitted to our coronary care unit for AMI between 2002 and 2009 who developed new-onset AF. The control group was an age and gender matched group of AMI patients who did not have AF. Management and recurrent AF, non-fatal stroke, and mortality data were collected from subsequent hospitalizations and outpatient records. Of 1,991 AMI admissions, new-onset AF was diagnosed in 100 (4.1%). Patients' age was 70 (±12), 32% were female, 58% had ST-elevation AMI and 53% had moderate or worse systolic dysfunction. AF recurred during index admission in 33%. During mean follow-up of 41 months, AF recurred in 22 and 4.5%, and non-fatal stroke occurred in 13 and 1% of the AF and control groups, respectively (p < 0.01 for both). The composite of death and non-fatal stroke was also significantly higher in the AF group, 39 versus 29% (p = 0.02). Oral anti-coagulation was used in only 24% of the AF group and was a significant predictor of stroke-free survival (p = 0.04). New onset AF in the AMI setting carries a substantial future risk for stroke and should not be regarded as a benign, transient complication of the acute event. Long term anticoagulation is underused and is associated with improved stroke-free survival.

Disparities in management of new-onset atrial fibrillation in the emergency department despite adherence to the current guidelines: data from a large metropolitan area

Atrial Fibrillation management is still a matter for debate. Past research has largely been based on the outpatient setting in which patients are followed during ambulatory visits. Very little data exist on the optimal management of AF in the Emergency Department (ED). This study investigated which factors drive different AF treatments in the ED, describing their use in different hospitals. Finally, the efficacy of different strategies in terms of cardioversion in the ED was analyzed. Charts of patients treated for atrial fibrillation (AF) were collected in 6 EDs in a large metropolitan area over a 24-consecutive month period and were reviewed and analysed. Demographics, comorbidities, treatment strategy and ED outcome were collected. Inclusion criteria were symptom onset <3 weeks and stable hemodynamic conditions at presentation. A propensity score was used to adjust for baseline clinical characteristics and to compare the efficacy of different treatments. 3,085 patients were included in the analysis. Variables associated with a rhythm control strategy were onset of symptoms <48 h, age, dyspnea, palpitations, renal failure and the presence of a mechanical valve. Different EDs applied different strategies in terms of drugs used and the electrocardioversion rate, showing heterogeneity in AF management. Adjusting for the propensity score, electrocardioversion and antidysrhythmic drugs of class Ic were more effective than a wait-and-watch strategy in the ED. Despite international guidelines being respected, AF management is heterogeneous in different ED settings. A rhythm control strategy with electrocardioversion and Class Ic drugs is more effective than a wait-and watch approach during the ED visit. Further research, toward an evidence-based approach to the emergent management of AF in the ED, is still needed.

Antioxidant Therapy for Atrial Fibrillation: What Is the Next Step?

I read with interest the timely article by Rasoli and colleagues, who reviewed the literature on the efficacy of antioxidant vitamins in the management of atrial fibrillation (AF) [1]. Those authors emphasized an important clinical issue: despite considerable evidence of the role of oxidative stress in the pathogenesis of AF, antioxidant vitamins have not been shown to exert an impressive antiarrhythmic effect in clinical trials. In addition to the authors' explanations for that finding, it may also be possible that treatment with a general reactive oxygen species (ROS) scavenger is ineffective, regardless of the type or potency of the scavenger. This may occur because ROS are a wide range of (usually) highly active molecules that, when they are formed, react with proteins and lipids in their immediate vicinity. Therefore, ROS scavengers cannot prevent the effects of already formed ROS molecules. In addition, those scavengers may not neutralize all forms of ROS molecules, some of which may remain to exert a downstream arrhythmic effect. Inhibiting the major source of excess ROS is a different therapeutic approach that may prove effective in the management of various types of arrhythmia. The major sources of cardiac ROS are nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, the mitochondria electron transport chain, and uncoupled endothelial nitric oxide synthase. Those sources of ROS are interrelated, and the activation of one may result in the increased production of ROS by other sources, particularly by mitochondria (ROS-induced-ROS release) [2]. Under different conditions and for each type of AF, one or some of the main sources of ROS may play the central role in the genesis of arrhythmia. It has been shown that NADPH oxidase is upregulated in initial stages of AF [3], and therefore, NADPH oxidase inhibitors may be effective in the management of new onset AF and postoperative AF [4]. However, the upregulation of NADPH oxidase was found to be transient and only in initial stages of AF, and therefore, its inhibition may not be an effective therapeutic strategy for the management of chronic AF [3]. Because a considerable portion of a cardiomyocyte is occupied by mitochondria [5] and because mitochondria plays a central role in ROS-induced-ROS release, mitochondria-targeted antioxidant therapy may prove to be the most effective antioxidant therapy for management of chronic AF. We have recently observed the impressive antiarrhythmic effect of Mito-TEMPO, a mitochondria-targeted antioxidant, in the prevention of ventricular arrhythmias in a mouse model of angiotensin-II activation [6]. Thus, it could be hypothesized that mitochondria-targeted antioxidants can effectively prevent chronic AF.

Ibutilide and amiodarone in management of new-onset atrial fibrillation after coronary artery bypass grafting: a comparison of safety and efficacy

Objective To compare the safety and efficacy of ibutilide and amiodarone in converting post-coronary artery bypass grafting(CABG) new-onset atrial fibrillation(AF) to sinus rhythm.Methods This study was a prospective,single blinded,randomized clinical trial.Totally 100 patients who met the inclusion criteria were enrolled and were intravenously treated with ibutilide(group A) or amiodarone(group B).In group A,Ibutilide was administered at a dose of 1 mg in 10 min,which was repeated after an interval of another 10 min if the arrhythmia was not converted;ibutilide was not given anymore no matter the conversion was achieved or not.In group B,amiodarone was administered at a dose of 5 mg/kg for the first 30 min,followed by 1 200 mg in the next 24 h;amiodarone was not given anymore no matter the conversion was achieved or not.Immediate conversion rate,conversion time and post-operative recurrence rate within 30 days were compared between the two groups.Results No severe adverse reactions were observed in both groups.The immediate conversion rate of group A was significantly higher than that of group B(82% vs 58%,P 0.01),and the conversion time was significantly shorter than that of group B(66 min vs 660 min,P 0.01).The post-operative recurrence rates were not significantly different between the two groups within 30 days after operation(7.3% vs 6.9%,P 0.05).Conclusion Ibutilide and amiodarone are both safe in converting post-CABG new-onset AF to sinus rhythm,and ibutilide is more effective,more rapid in functioning and with a higher efficacy.