Design and rationale for the WARFA trial: a randomized controlled cross-over trial testing the therapeutic equivalence of branded and generic warfarin in atrial fibrillation patients in Brazil.

BACKGROUND: Warfarin is a commonly used anticoagulant. Whether a given dose of the different formulations of Brazilian warfarin will result in the same effect on the international normalized ratio (INR) is uncertain. The aim of the WARFA trial is to determine whether the branded and two generic warfarins available in Brazil differ in their effect on the INR. METHODS: WARFA is a cross-over RCT comparing three warfarins. The formulations tested are the branded Marevan® (Uniao Quimica/Farmoquimica) and two generic warfarin (manufactured respectively by Uniao Quimica Farmaceutica Nacional and Laboratorio Teuto Brasileiro). All of them were manufactured in Brazil, are available in all settings of the Brazilian healthcare system and were purchased from retail drugstores. Eligible participants had atrial fibrillation or flutter, had been using warfarin for at least 2 months with a therapeutic range of 2.0-3.0 and had low variability in INR results during the 1st period of the trial. Our primary outcome, for which we have an equality hypothesis, is the difference between warfarins in the mean absolute difference between two INR results, obtained after three and 4 weeks with each drug. Our secondary outcomes, that will be tested for inequality (except for the mean INR, which will be tested for equality), include the difference in the warfarin dose, and time in therapeutic range. Clinical events and adherence were also recorded and will be reported. DISCUSSION: To our knowledge, WARFA will be the first comparison of the more readily applicable INR results between branded and generic warfarins in Brazil. WARFA is important because warfarins are commonly switched between in the course of a chronic treatment in Brazil. Final results of WARFA are expected in May 2017. TRIAL REGISTRATION: ClinicalTrials.gov NCT02017197 . Registered 11 December 2013.

The epidemiology and management of recent-onset atrial fibrillation and flutter presenting to the Emergency Department.

OBJECTIVES: Atrial fibrillation (AF) and flutter are common tachyarrhythmias seen in the Emergency Department (ED). The management of recent-onset AF remains poorly defined. Two management strategies have been proposed: rhythm control versus rate control. The aims of this study were to investigate the epidemiology and management of recent-onset AF presenting to one large tertiary ED. METHODS: Retrospective analysis of ED records was carried out using the ED PAS database to identify eligible patients presenting between 1 July 2009 and 30 June 2011 with onset of AF in the previous 7 days. Patients were included for analysis if it was their first presentation, first diagnosis or a paroxysm of atrial fibrillation. RESULTS: A total of 494 patients (625 presentations) were analysed. AF (n=564; 90.2%) and flutter (n=61; 9.8%) were the presenting rhythms. In all, 374 (53.8%) presentations were paroxysmal atrial fibrillation. For patients with AF, rhythm control was attempted in 171 (55.0%) patients presenting less than 48 h after symptom onset. Pharmacotherapy was the approach in 105 (31.4%) patients, compared with direct current cardioversion (n=45; 26.3%). Twenty-one patients received both. Flecainide (n=85) and amiodarone (n=33) were the main first-line pharmacotherapies, restoring sinus rhythm in 81.3 and 81.4% of patients, respectively. The overall efficacy of direct current cardioversion in restoring sinus rhythm was similar (78.8%). Eighty-one patients presented more than 48 h after symptom onset. Of those patients managed in the ED (n=38; 71.7%) were managed with rate control. The majority of patients with atrial flutter presented less than 48 h after symptom onset (n=48; 78.7%). Sixteen of these patients were managed with rhythm control strategies in the ED. CONCLUSION: The epidemiology of recent-onset AF in this series is comparable with previous publications. Rhythm control was only attempted in approximately half of all eligible patients. There was no single-favoured management strategy. Our results mirror the literature in emphasizing the variation in management and the lack of robust evidence guiding the management of recent-onset AF and flutter.

Estimation of potential cost savings associated with reduced rates of cardiovascular hospitalization among atrial fibrillation/flutter patients treated with dronedarone in the ATHENA trial.

The aim of this study was to estimate, from a US payer perspective, potential cost savings resulting from the reduction in cardiovascular (CV) hospitalizations obtained with dronedarone in the ATHENA (A Placebo-Controlled, Double-Blind, Parallel Arm Trial to Assess the Efficacy of Dronedarone 400 mg bid for the Prevention of Cardiovascular Hospitalization or Death from any Cause in PatiENts with Atrial Fibrillation/Atrial Flutter) trial. ATHENA randomized atrial fibrillation/flutter patients to dronedarone (n=2301) or placebo (n=2327) plus standard care. Dronedarone significantly reduced first CV hospitalization/all-cause mortality over 12-30 months of follow-up. CV hospitalization costs (2008 values) from a US cohort of ATHENA-like atrial fibrillation/flutter patients with Medicare supplemental insurance (n=10,200) and diagnosis-related group costs of adverse event-related hospitalizations were applied to hospitalizations occurring in ATHENA. The impact of cost variation was assessed using Monte Carlo simulation. In ATHENA, dronedarone reduced the overall CV hospitalization rate (vs. placebo) by 29% over the first 12 months (33.36 vs. 47.19 events per 100 patients) and by 25% over the full study (51.15 vs. 68.55 events per 100 patients). Adverse event-related hospitalization rates (dronedarone vs. placebo) were low (0.48 vs. 0.21 and 0.56 vs. 0.26 events per 100 patients over 12 months and the full study, respectively). Overall hospitalization cost savings were estimated at $1329 and $1763 per patient over 12 months and the full study, respectively. Cost savings were relatively stable [mean (95% confidence interval): $1330 ($994-$1676) for the first 12 months and $1763 ($1369-$2184) for the full study] over 10,000 cycles of random variation.

Temporal pattern and costs of rehospitalization in atrial fibrillation/atrial flutter patients with one or more additional risk factors.

OBJECTIVES: The ATHENA study showed that use of dronedarone reduced rates of first cardiovascular (CV) hospitalization in atrial fibrillation/flutter (AF/AFL) patients. AF is associated with high costs to payers, which are driven by high rates of hospitalization. This retrospective cohort study examined readmission patterns and costs to US payers in real-world AF/AFL patients with ≥1 additional risk factor (ARF). METHODS: Patients hospitalized (January 2005-March 2008) with AF/AFL as primary diagnosis and having ≥1 year of health coverage, before and after their first (index) admission, were identified in the PharMetrics Patient-Centric database. As in the ATHENA study, patients had to be ≥75 years of age or ≥70 years, with ≥1 ARF. Rehospitalization patterns (all-cause, all CV-related [including AF/AFL] and AF/AFL-related alone) were examined over 1 year post-index, and costs of index vs later AF/AFL admissions compared. RESULTS: The study included 3498 patients (mean 80 [SD 7.6] years; 42.4% men). Over 1 year, 1389 patients (39.7%) were rehospitalized for any cause (mean 1.7 [SD 1.3] events/patient), with 1223 patients (35.0%) undergoing CV-related (mean 1.6 [SD 1.0] events/patient) and 935 (26.7%) undergoing AF-related rehospitalization (mean 1.4 [SD 0.8] events/patient). Common causes of CV-related readmissions (primary diagnosis) were AF/AFL (47.5%), congestive heart failure (CHF) (9.9%), coronary artery disease (7.4%), and stroke/transient ischemic attack (6.2%). Readmission rates at 3 months were 16.2% (all-cause), 14.3% (all CV-related including AF/AFL), and 10.5% (AF/AFL-related alone). AF/AFL readmissions (primary diagnosis) were longer than initial hospitalizations (mean total 6.9 [SD 12.9] vs 4.3 [SD 5.1] days, p < 0.0001) and more costly (median $1819 [25th percentile $1066, 75th percentile $5623] vs $1707 [25th percentile $1102, 75th percentile $4749]). LIMITATIONS: This study excluded patients with pre-existing CHF, did not require electrocardiogram confirmation of AF/AFL diagnosis, and did not distinguish between paroxysmal, persistent, and permanent AF. CONCLUSIONS: AF/AFL patients with ≥1 ARF have high readmission rates. AF/AFL-related readmissions incur higher costs than the initial AF/AFL admissions.

Evaluation of dronedarone use in the US patient population between 2009 and 2010: a descriptive study using a claims database.

BACKGROUND: The utilization pattern of dronedarone was unknown, especially regarding prescribers' compliance with the product's prescribing information (PI) following its availability and the implementation of the Food and Drug Administration-approved risk evaluation and mitigation strategy for the drug in the United States. OBJECTIVE: This study was designed to evaluate the dronedarone prescribers' adherence to PI regarding the following contraindications: (1) patients with heart failure (HF) with a recent decompensation requiring hospitalization or referral to a specialist, (2) concomitant use of potent CYP3A4 inhibitors, and (3) concomitant use of QT-prolonging drugs. METHODS: Patients prescribed dronedarone between July 2009 and August 2010 were identified through LabRx. The following rates surrounding dronedarone use were examined: (1) atrial fibrillation or atrial flutter in the past year, (2) worsening or hospitalization for HF within the month before prescription, and (3) concomitant prescription of potent CYP3A4 inhibitors and concomitant prescription of QT-prolonging drugs within the following month. RESULTS: A total of 4595 dronedarone prescriptions were filled by 1820 patients. More than 94% of the participants had ≥1 diagnosis of atrial fibrillation or atrial flutter in the previous year. Worsening of or hospitalization for HF was found in 61 (3.4%) patients within the month before receiving dronedarone, including 18 patients with HF as the primary cause for hospitalization. Potent CYP3A4 inhibitors were prescribed to 10 (0.6%) patients within a month following dronedarone initiation, 6 of whom received them for topical use only. QT-prolonging drugs were prescribed to 67 (3.7%) patients within a month following dronedarone initiation, among which >90% were other antiarrhythmics. CONCLUSIONS: Dronedarone was used mostly in compliance with PI and risk evaluation and mitigation strategy in the studied population. In the LabRx database, dronedarone was commonly dispensed to patients with cardiovascular risk factors and rarely dispensed to patients with contraindications such as worsening HF or hospitalization for HF or with concomitant prescriptions of potent CYP3A4 inhibitors, QT-prolonging drugs, or both.

Economic impact to employers of treatment options for cardiac arrhythmias in the US health system.

OBJECTIVE: To measure relative employer-sponsored postablation costs for cardiac arrhythmias (CA), specifically atrial fibrillation (AF). METHODS: Regression-Controlled Employee/Spouse Database study (2001 to 2008) comparing CA patients with and without ablation and AF patients with and without ablation. Regression-adjusted monthly medical, pharmacy, sick leave, and short-term disability costs were calculated 11 months before index to 36 months after index (first ablation date or average date for nonablation patients). Relative pre/postindex comparisons between ablation and nonablation cohorts were calculated and time until ablation procedure cost recovery extrapolated. RESULTS: Few CA (280 of 11,291; 2.48%) and AF (93 of 3062; 3.04%) patients received ablation. Ablation cohorts cost less than nonablation cohorts postablation. Estimated total ablation-period costs were recovered 38 to 50 months postablation, including employee absence payment recovery within 18 months. CONCLUSION: Current ablation use in employer-sponsored health plans may improve health care and absence costs over time.

Dronedarone for the treatment of atrial fibrillation and atrial flutter.

This paper presents a summary of the evidence review group (ERG) report on the clinical effectiveness and cost-effectiveness of dronedarone for the treatment of atrial fibrillation (AF) or atrial flutter based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal process. The population considered in the submission were adult clinically stable patients with a recent history of or current non-permanent AF. Comparators were the current available anti-arrhythmic drugs: class 1c agents (flecainide and propafenone), sotalol and amiodarone. Outcomes were AF recurrence, all-cause mortality, stroke, treatment discontinuations (due to any cause or due to adverse events) and serious adverse events. The main evidence came from four phase III randomised controlled trials, direct and indirect meta-analyses from a systematic review, and a synthesis of the direct and indirect evidence using a mixed-treatment comparison. Overall, the results from the different synthesis approaches showed that the odds of AF recurrence appeared statistically significantly lower with dronedarone and other anti-arrhythmic drugs than with non-active control, and that the odds of AF recurrence are statistically significantly higher for dronedarone than for amiodarone. However, the results for outcomes of all-cause mortality, stroke and treatment discontinuations and serious adverse events were all uncertain. A discrete event simulation model was used to evaluate dronedarone versus antiarrhythmic drugs and standard therapy alone. The incremental cost-effectiveness ratio of dronedarone was relatively robust and less than 20,000 pounds per quality-adjusted life-year. Exploratory work undertaken by the ERG identified that the main drivers of cost-effectiveness were the benefits assigned to dronedarone for all-cause mortality and stroke. Dronedarone is not cost-effective relative to its comparators when the only effect of treatment is a reduction in AF recurrences. In conclusion, uncertainties remain in the clinical effectiveness and cost-effectiveness of dronedarone. In particular, the clinical evidence for the major drivers of cost-effectiveness (all-cause mortality and stroke), and consequently the additional benefits attributed in the economic model to dronedarone compared to other anti-arrhythmic drugs are highly uncertain. The final guidance, issued by NICE on 25 August 2010, states that: Dronedarone is recommended as an option for the treatment of non-permanent atrial fibrillation only in people: whose atrial fibrillation is not controlled by first-line therapy (usually including beta-blockers), that is, as a second-line treatment option, and who have at least one of the following cardiovascular risk factors: - hypertension requiring drugs of at least two different classes, diabetes mellitus, previous transient ischaemic attack, stroke or systemic embolism, left atrial diameter of 50 mm or greater, left ventricular ejection fraction less than 40% (noting that the summary of product characteristics [SPC] does not recommend dronedarone for people with left ventricular ejection fraction less than 35% because of limited experience of using it in this group) or age 70 years or older, and who do not have unstable New York Heart Association (NYHA) class III or IV heart failure. Furthermore, 'People who do not meet the criteria above who are currently receiving dronedarone should have the option to continue treatment until they and their clinicians consider it appropriate to stop'.

Cost burden of cardiovascular hospitalization and mortality in ATHENA-like patients with atrial fibrillation/atrial flutter in the United States.

BACKGROUND: The ATHENA trial (A placebo-controlled, double-blind, parallel arm Trial to assess the efficacy of dronedarone 400 mg bid for the prevention of cardiovascular Hospitalization or death from any cause in patiENts with Atrial fibrillation/atrial flutter) demonstrated that dronedarone reduced the risk of cardiovascular (CV) hospitalization/death by 24% (P < 0.001) in patients with atrial fibrillation (AF) and atrial flutter (AFL). HYPOTHESIS: In order to estimate the cost savings associated with dronedarone use, we estimated the costs associated with CV hospitalizations and inpatient mortality in a large cohort of ATHENA-like patients. METHODS: In this retrospective analysis, we evaluated the cost of CV hospitalization/mortality in real-world ATHENA-like patients without heart failure and with employer-sponsored Medicare supplemental insurance in the United States. Patients similar to those in ATHENA (age > or = 70 years with AF/AFL and > or = 1 stroke risk factor, without heart failure) who were hospitalized between January 2, 2005, and January 1, 2007, were identified from the MarketScan databases from Thomson Reuters. Health care costs were evaluated during the 12 months following the index hospitalization. RESULTS: The analysis included 10 200 ATHENA-like patients. Hospitalization for CV causes occurred in 53.9% of patients, with a total of 6700 CV hospitalizations for fatal/nonfatal causes. The most common nonfatal causes of CV hospitalizations were AF/other supraventricular rhythm disorders (20.2% of all CV hospitalizations), congestive heart failure (CHF; 14.3%), and transient ischemic attack (TIA)/stroke (10.7%). Mean costs per CV hospitalization for nonfatal causes were $10,908. Inpatient deaths from CV causes occurred in 264 (2.6%) patients; the most common causes of CV inpatient death were intracranial/gastrointestinal hemorrhage (24.2% of CV deaths), TIA/stroke (17.0%), and CHF (15.9%). Mean hospitalization costs per CV inpatient death were $18,565. CONCLUSIONS: Health care costs associated with CV hospitalizations and inpatient deaths among ATHENA-like patients in the US are high. Novel antiarrhythmic therapies such as dronedarone, with the potential to reduce CV hospitalizations/mortality in similar patients, could decrease health care costs if adopted in clinical practice.

Current treatment options for atrial flutter and results with cryocatheter ablation.

Rhythm disturbances arising in the upper chambers of the heart are not uncommon. They are associated with a heavy burden of illness for the affected individual, as well as society in general. Atrial flutter, a re-entrant atrial tachycardia, is one such rhythm disturbance. The objective of this review article is twofold: first, to provide a brief insight into atrial flutter and the typical treatments for this arrhythmia in clinical practice; and second, to give an in-depth account of cryocatheter ablation as a relatively new treatment option for this potentially debilitating condition. The many recent clinical studies documenting the use of cryocatheter ablation for treatment of atrial flutter are presented, and their results briefly discussed. Overall, as cryocatheter ablation embeds itself among the arsenal of treatments for atrial flutter, the promising results from clinical studies appear destined to elevate cryocatheter ablation to a premier position among the treatment options for atrial flutter.

New antiarrhythmic agents for atrial fibrillation and atrial flutter.

Atrial fibrillation is the most common sustained cardiac arrhythmia and is a frequent reason for antiarrhythmic therapy. Existing antiarrhythmic drugs have important side effects and presently the therapy to maintain sinus rhythm is not superior to a strategy of controlling excessive heart rate. This review summarises current strategies to improve antiarrhythmic therapy for atrial fibrillation. The most important strategies are: i) to develop drugs without proarrhythmic effects--development of drugs devoid of QT prolonging potential is the main strategy; ii) multiple channel-blocking drugs--inspired by the efficacy of amiodarone, several drugs are being developed that have similar electrophysiological properties as amiodarone, but without the extracardiac side effects; iii) drugs that act exclusively in the atria--the atria contain specific potassium channels, and several drugs that act only on these channels are in development; and iv) antiarrhythmic therapy without effects on ion channels--inhibition of the renin-angiotensin system and steroid therapy has been shown to have some effect in the treatment of atrial fibrillation. Many drugs are in development and the therapeutic scenario for treatment of atrial fibrillation may change quickly.

Flecainide versus ibutilide for immediate cardioversion of atrial fibrillation of recent onset.

AIMS: This study compared the efficacy and safety of intravenous flecainide and ibutilide for immediate cardioversion of atrial fibrillation (AF). METHODS AND RESULTS: We conducted a prospective, randomised trial, including 207 patients with AF of recent onset (< or = 48 h). Flecainide was given over 20 min at a dose of 2 mg/kg body weight (maximum 200 mg), ibutilide was infused at a dose of 1 mg (or 0.01 mg/kg if less than 60 kg) over 10 min, followed by a 10 min observation period and an identical second dose if AF did not convert to sinus rhythm (SR). Treatment was considered successful if SR occurred within 90 min of starting medication. The conversion rates were 56.4% in patients given flecainide and 50.0% in patients given ibutilide (P=0.34). Multivariate analysis revealed that a lower age for women independently increased the probability of conversion. None of the other variables, including left atrial size, left ventricular systolic function, presence of left ventricular hypertrophy, plasma levels of potassium or magnesium at baseline, or concomitant use of digoxin, beta-blocker, diltiazem or verapamil were predictors of conversion. The frequency of adverse events was comparable in the two treatment groups. CONCLUSIONS: There was no significant difference in the cardioversion efficacy or in the risk of adverse events between flecainide and ibutilide in patients with AF of recent onset. In patients without contraindications to both medications, the physician's choice has to be governed by other factors.

New antiarrhythmic agents for atrial fibrillation and atrial flutter: United States drug market response as an indicator of acceptance.

OBJECTIVE: To determine how well dofetilide and Betapace AF (sotalol, approved solely for atrial fibrillation and atrial flutter), with their detailed dosing and monitoring guidelines for safety, were accepted into clinical practice during the 2 calendar years after their introduction. METHODS AND RESULTS: We reviewed the number of new, refill, and total prescriptions of all antiarrhythmic agents in the United States from April 2000-December 2001 to assess use of dofetilide and Betapace AF in the drug market. Both were prescribed very infrequently throughout the study period. In addition, the infrequent reported use of these drugs for patients with atrial fibrillation and flutter indicated poor acceptance of these agents by prescribing physicians. We speculated that the restricted distribution and required educational program for dofetilide, as well as the availability of generic sotalol products, may have discouraged physicians from prescribing both dofetilide and Betapace AE CONCLUSION: A common goal for both the dofetilide risk-management program and the creation of a sotalol product indicated solely for atrial fibrillation and atrial flutter was to provide safer treatment for patients with these arrhythmias. Unfortunately, limited penetration of dofetilide and Betapace AF into the U.S. market suggests that drugs without a risk-management program or detailed dosing guidelines were more likely than dofetilide or Betapace AF to be selected for treatment of atrial fibrillation and atrial flutter.

Esmolol versus diltiazem in the treatment of postoperative atrial fibrillation/atrial flutter after open heart surgery.

BACKGROUND: Supraventricular tachyarrhythmias are common after open heart surgery. Possible causative factors for these arrhythmias include operative trauma, atrial ischemia, electrolyte imbalances, pericardial irritation, and excess catecholamines. Two agents commonly used to control ventricular rate in atrial fibrillation or atrial flutter (AF/AFL) are beta-blockers and calcium channel blockers. METHODS AND RESULTS: This randomized study was designed to compare the safety and efficacy of intravenous diltiazem versus intravenous esmolol in patients with postoperative AF/AFL after coronary bypass surgery and/or valve replacement surgery. A comparative cost analysis was also performed. Thirty patients received either esmolol (n = 15) or diltiazem (n = 15) for AF/AFL. During the first 6 hours of treatment, 66.6% of esmolol-treated patients converted to sinus rhythm compared with 13.3% of the diltiazem-treated patients (P <.05). At 24 hours, 66.6% of the diltiazem group converted to SR compared with 80% of the esmolol group (not significant). Drug-induced side effects, time to rate control (<90 beats/min), number of patients requiring cardioversion, and length of hospitalization were similar for the two groups. The drug cost/successfully treated patient for esmolol versus diltiazem was $254 versus $437 at 6 hours and $529 versus $262 at 24 hours. CONCLUSIONS: Although this is a small study, it suggests that esmolol is more effective in converting patients to normal sinus rhythm than diltiazem during the initial dosing period. No differences in conversion rates were observed between the two groups after 24 hours. Additional studies are needed to confirm whether esmolol is the initial drug of choice in patients with postoperative AF/AFL after coronary bypass surgery.

Cost-effective management of acute atrial fibrillation: role of rate control, spontaneous conversion, medical and direct current cardioversion, transesophageal echocardiography, and antiembolic therapy.

Management strategies for the acute treatment of atrial fibrillation (AF) include: (1) the use of intravenous drugs for rate control, (2) drug termination, or (3) direct current (DC) cardioversion. Delays in cardioversion can promote atrial remodeling and add thromboembolic risk. Rate control awaiting spontaneous or pharmacologic conversion may be a cost-effective strategy in patients presenting with recent onset of symptoms. Early DC cardioversion can be cost-effective and minimize antiembolic therapy issues in the acute setting. In patients presenting with AF of unknown or >48 hours' duration, rate control and therapeutic warfarin for 3-4 weeks followed by medical or DC cardioversion is standard practice. However, delays in conversion promote atrial remodeling that makes restoration of sinus rhythm more difficult and increases the likelihood of postcardioversion AF recurrence. Transesophageal echocardiography can identify patients at low risk for a cardioversion-related embolic event and allows cardioversion to be performed earlier, thereby minimizing atrial remodeling.

The cost-effectiveness of ibutilide versus electrical cardioversion in the conversion of atrial fibrillation and flutter to normal rhythm.

Atrial fibrillation and atrial flutter are cardiac rhythm disorders that are often symptomatic and may interfere with the heart's function, limiting its effectiveness. These arrhythmias are responsible for a large number of hospitalizations at a significant cost to the healthcare system. Electrical cardioversion (EC) is the most common nonpharmacologic intervention used to convert atrial fibrillation and atrial flutter to normal rhythm. Electrical cardioversion is highly successful in converting patients to normal rhythm; however, it is more traumatic and resource intensive than pharmacologic treatment. Recently, a new rapid-acting drug, ibutilide, was approved for the conversion of atrial fibrillation and atrial flutter. Ibutilide is administered through intravenous infusion and does not require anesthetization of the patient, as is required for EC. A decision-tree model was developed to estimate the cost-effectiveness of ibutilide therapy compared with EC therapy. Clinical outcomes were based on a phase III trial of ibutilide, and resource use was based on the literature and physician clinical judgment. A stepped conversion regimen of first-line ibutilide followed by EC for patients who fail to convert is less expensive and has a higher conversion rate than first-line EC. Sensitivity analysis shows that our results are robust to changes in cost and effectiveness estimates.

Direct-current cardioversion for the conversion of atrial flutter.

Hemodynamically stable atrial flutter should be treated with direct-current cardioversion using 200 J as an initial setting. This can be accomplished in an outpatient setting, saving the cost of hospitalization and avoiding the hazards of drug therapy.

Clinical decision analysis modeling: short-term control of ventricular response rate in atrial fibrillation or atrial flutter-digoxin versus diltiazem.

OBJECTIVE: To develop a clinical decision model to compare the outcome of therapy with digoxin versus diltiazem for short-term control of ventricular response rate (VRR) in patients with atrial fibrillation or atrial flutter. DESIGN: Review of data from two studies that examined the percentages of response and frequency of adverse reactions in patients treated with intravenous digoxin or diltiazem to control VRR in atrial fibrillation or flutter. We constructed a clinical decision model and performed sensitivity analysis to determine if the model's predictions could be altered. SETTING: Large teaching, university hospitals. PARTICIPANTS: Adults age 18 years or older treated with intravenous digoxin or intravenous diltiazem for atrial fibrillation or flutter (VRR > or = 120 beats/min). Patients with severe heart failure New York Heart Association class III or IV, a surgical procedure prior to the exacerbation, or an acute myocardial infarction were excluded. MEASUREMENTS AND MAIN RESULTS: We measured VRR control after 1 and 24 hours of therapy (VRR < 100 beats/min or decrease of > or = 20%) and assessed the likelihood that a patient would suffer an adverse drug reaction. Initial assumptions were that the probability digoxin would achieve VRR control was 0.10 (95% confidence interval 0.04-0.20) at 1 hour and 0.70 (95% CI 0.56-0.80) at 24 hours; the probability that diltiazem would achieve VRR control was 0.94 (95% CI 0.82-0.99) at 1 hour and 0.83 (95% CI 0.68-0.94) at 24 hours; and the probability of no serious adverse drug reaction would be 0.90 (95% CI 0.80-0.96) for digoxin and 0.96 (95% CI 0.86-0.98) for diltiazem. RESULTS: Diltiazem was superior to digoxin with respect to the composite end point score at 1 hour (91.20 vs 17.29) and 24 hours (81.65 vs 66.43). Digoxin was superior to diltiazem at 24 hours only if the VRR was assumed to be at the highest 95% CI limit for digoxin and simultaneously at the lowest 95% CI for diltiazem (74.62 vs 68.63). CONCLUSIONS: Clinical decision analysis suggests that intravenous diltiazem is superior to intravenous digoxin in controlling VRR in patients with atrial fibrillation or flutter.

Effectiveness and costs of digoxin treatment for atrial fibrillation and flutter.

Clinical outcomes and costs associated with the use of digoxin in atrial fibrillation and flutter were evaluated in a prospective, observational study at 18 academic medical centers in the United States. Data were collected on 115 patients (aged > 18 years) with atrial fibrillation or flutter who were treated with digoxin for rapid ventricular rate (> or = 120 beats/min). The median time to ventricular rate control (i.e., resting ventricular rate < 100 beats/min, decrease in ventricular rate of > 20%, or sinus rhythm) was 11.6 hours from the first dose of digoxin for all evaluable patients (n = 105) and 9.5 hours for those only receiving digoxin (n = 64). Before ventricular rate control, the mean +/- SD dose of digoxin administered was 0.80 +/- 0.74 mg, and a mean of 1.4 +/- 1.8 serum digoxin concentrations were ordered per patient. Concomitant beta-blocker or calcium antagonist therapy was instituted in 47 patients (41%); in 19 of these, combination therapy was initiated within 2 hours. Adenosine was administered to 13 patients (11%). Patients spent a median of 4 days (range 1 to 25) in the hospital; 28% spent time in a coronary/intensive care unit and 79% in a telemetry bed. Loss of control (i.e., resting ventricular rate returned to > 120 beats/min) occurred at least once in 50% of patients and was associated with a longer hospital stay (p < 0.05). Based on 1991 data, the estimated mean hospital bed cost for patients with atrial fibrillation or flutter was $3,169 +/- $3,174.(ABSTRACT TRUNCATED AT 250 WORDS)