Amiodarone in restoration and maintenance of sinus rhythm in patients with chronic atrial fibrillation after unsuccessful direct-current cardioversion

Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation

BACKGROUND

Atrial fibrillation is the most frequent sustained arrhythmia. Atrial fibrillation often recurs after restoration of normal sinus rhythm. Antiarrhythmic drugs have been widely used to prevent recurrence. This is an update of a review previously published in 2006, 2012 and 2015.

OBJECTIVES

To determine the effects of long-term treatment with antiarrhythmic drugs on death, stroke, drug adverse effects and recurrence of atrial fibrillation in people who had recovered sinus rhythm after having atrial fibrillation.

SEARCH METHODS

We updated the searches of CENTRAL, MEDLINE and Embase in January 2019, and ClinicalTrials.gov and WHO ICTRP in February 2019. We checked the reference lists of retrieved articles, recent reviews and meta-analyses.

SELECTION CRITERIA

Two authors independently selected randomised controlled trials (RCTs) comparing any antiarrhythmic drug with a control (no treatment, placebo, drugs for rate control) or with another antiarrhythmic drug in adults who had atrial fibrillation and in whom sinus rhythm was restored, spontaneously or by any intervention. We excluded postoperative atrial fibrillation.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed quality and extracted data. We pooled studies, if appropriate, using Mantel-Haenszel risk ratios (RR), with 95% confidence intervals (CI). All results were calculated at one year of follow-up or the nearest time point.

MAIN RESULTS

This update included one new study (100 participants) and excluded one previously included study because of double publication. Finally, we included 59 RCTs comprising 20,981 participants studying quinidine, disopyramide, propafenone, flecainide, metoprolol, amiodarone, dofetilide, dronedarone and sotalol. Overall, mean follow-up was 10.2 months.All-cause mortalityHigh-certainty evidence from five RCTs indicated that treatment with sotalol was associated with a higher all-cause mortality rate compared with placebo or no treatment (RR 2.23, 95% CI 1.03 to 4.81; participants = 1882). The number need to treat for an additional harmful outcome (NNTH) for sotalol was 102 participants treated for one year to have one additional death. Low-certainty evidence from six RCTs suggested that risk of mortality may be higher in people taking quinidine (RR 2.01, 95% CI 0.84 to 4.77; participants = 1646). Moderate-certainty evidence showed increased RR for mortality but with very wide CIs for metoprolol (RR 2.02, 95% CI 0.37 to 11.05, 2 RCTs, participants = 562) and amiodarone (RR 1.66, 95% CI 0.55 to 4.99, 2 RCTs, participants = 444), compared with placebo.We found little or no difference in mortality with dofetilide (RR 0.98, 95% CI 0.76 to 1.27; moderate-certainty evidence) or dronedarone (RR 0.86, 95% CI 0.68 to 1.09; high-certainty evidence) compared to placebo/no treatment. There were few data on mortality for disopyramide, flecainide and propafenone, making impossible a reliable estimation for those drugs.Withdrawals due to adverse eventsAll analysed drugs increased withdrawals due to adverse effects compared to placebo or no treatment (quinidine: RR 1.56, 95% CI 0.87 to 2.78; disopyramide: RR 3.68, 95% CI 0.95 to 14.24; propafenone: RR 1.62, 95% CI 1.07 to 2.46; flecainide: RR 15.41, 95% CI 0.91 to 260.19; metoprolol: RR 3.47, 95% CI 1.48 to 8.15; amiodarone: RR 6.70, 95% CI 1.91 to 23.45; dofetilide: RR 1.77, 95% CI 0.75 to 4.18; dronedarone: RR 1.58, 95% CI 1.34 to 1.85; sotalol: RR 1.95, 95% CI 1.23 to 3.11). Certainty of the evidence for this outcome was low for disopyramide, amiodarone, dofetilide and flecainide; moderate to high for the remaining drugs.ProarrhythmiaVirtually all studied antiarrhythmics showed increased proarrhythmic effects (counting both tachyarrhythmias and bradyarrhythmias attributable to treatment) (quinidine: RR 2.05, 95% CI 0.95 to 4.41; disopyramide: no data; flecainide: RR 4.80, 95% CI 1.30 to 17.77; metoprolol: RR 18.14, 95% CI 2.42 to 135.66; amiodarone: RR 2.22, 95% CI 0.71 to 6.96; dofetilide: RR 5.50, 95% CI 1.33 to 22.76; dronedarone: RR 1.95, 95% CI 0.77 to 4.98; sotalol: RR 3.55, 95% CI 2.16 to 5.83); with the exception of propafenone (RR 1.32, 95% CI 0.39 to 4.47) for which the certainty of evidence was very low and we were uncertain about the effect. Certainty of the evidence for this outcome for the other drugs was moderate to high.StrokeEleven studies reported stroke outcomes with quinidine, disopyramide, flecainide, amiodarone, dronedarone and sotalol. High-certainty evidence from two RCTs suggested that dronedarone may be associated with reduced risk of stroke (RR 0.66, 95% CI 0.47 to 0.95; participants = 5872). This result is attributed to one study dominating the meta-analysis and has yet to be reproduced in other studies. There was no apparent effect on stroke rates with the other antiarrhythmics.Recurrence of atrial fibrillationModerate- to high-certainty evidence, with the exception of disopyramide which was low-certainty evidence, showed that all analysed drugs, including metoprolol, reduced recurrence of atrial fibrillation (quinidine: RR 0.83, 95% CI 0.78 to 0.88; disopyramide: RR 0.77, 95% CI 0.59 to 1.01; propafenone: RR 0.67, 95% CI 0.61 to 0.74; flecainide: RR 0.65, 95% CI 0.55 to 0.77; metoprolol: RR 0.83 95% CI 0.68 to 1.02; amiodarone: RR 0.52, 95% CI 0.46 to 0.58; dofetilide: RR 0.72, 95% CI 0.61 to 0.85; dronedarone: RR 0.85, 95% CI 0.80 to 0.91; sotalol: RR 0.83, 95% CI 0.80 to 0.87). Despite this reduction, atrial fibrillation still recurred in 43% to 67% of people treated with antiarrhythmics.

AUTHORS' CONCLUSIONS

There is high-certainty evidence of increased mortality associated with sotalol treatment, and low-certainty evidence suggesting increased mortality with quinidine, when used for maintaining sinus rhythm in people with atrial fibrillation. We found few data on mortality in people taking disopyramide, flecainide and propafenone, so it was not possible to make a reliable estimation of the mortality risk for these drugs. However, we did find moderate-certainty evidence of marked increases in proarrhythmia and adverse effects with flecainide.Overall, there is evidence showing that antiarrhythmic drugs increase adverse events, increase proarrhythmic events and some antiarrhythmics may increase mortality. Conversely, although they reduce recurrences of atrial fibrillation, there is no evidence of any benefit on other clinical outcomes, compared with placebo or no treatment.

[Is it worth delivering Direct-Current Counter shock to critically ill patients with supra-ventricular tachyarrhythmia?]

Supra-ventricular tachyarrhythmia and its treatment have been poorly investigated in ICU patients.

AIMS

To evaluate efficacy and safety of cardioversion for supra-ventricular tachyarrhythmia in the intensive care unit (ICU).

PATIENTS AND METHODS

Prospective inclusion of all patients who presented supra-ventricular tachyarrhythmias lasting≥30seconds in a single medico-surgical ICU, except cardiac surgery. Anti-arrhythmic drugs and/or direct-current cardioversion were administered on a liberal basis.

RESULTS

During the 15-month study period, 108/846 patients (12.8%) experienced supra-ventricular tachyarrhythmias. Anti-arrhythmic drugs were administered in 78 patients (72%); mostly amiodarone (92%), and/or magnesium (23%), resulting in an overall conversion rate of 68%. Direct-current cardioversion was used in 26 patients (24%), (24 patients received drug enhancement by anti-arrhythmic drugs) with an immediate 80.8%-success rate.

CONCLUSION

Direct-current cardioversion was associated with sustained conversion to sinus rhythm in 80.8% of ICU patients with supra-ventricular tachyarrhythmias, although most of them had already received drug enhancement.

Atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disorder, and increases in prevalence with increasing age and the number of cardiovascular comorbidities. AF is characterized by a rapid and irregular heartbeat that can be asymptomatic or lead to symptoms such as palpitations, dyspnoea and dizziness. The condition can also be associated with serious complications, including an increased risk of stroke. Important recent developments in the clinical epidemiology and management of AF have informed our approach to this arrhythmia. This Primer provides a comprehensive overview of AF, including its epidemiology, mechanisms and pathophysiology, diagnosis, screening, prevention and management. Management strategies, including stroke prevention, rate control and rhythm control, are considered. We also address quality of life issues and provide an outlook on future developments and ongoing clinical trials in managing this common arrhythmia.

Disappointing Success of Electrical Cardioversion for New-Onset Atrial Fibrillation in Cardiosurgical ICU Patients

OBJECTIVES

To assess the success of electrical cardioversion for the treatment of new-onset atrial fibrillation in critically ill patients and to evaluate the stability of sinus rhythm in responders during the subsequent 24 hours.

DESIGN

Retrospective study.

SETTING

Twelve-bed cardiosurgical ICU at a university hospital.

PATIENTS

Seventy-two consecutive patients with postoperative new-onset atrial fibrillation (<7 d of duration) treated by electrical cardioversion.

INTERVENTIONS

Electrical cardioversion using synchronized biphasic shocks.

MEASUREMENTS AND MAIN RESULTS

During 144 electrical cardioversions, 209 shocks were delivered to 72 patients. Maximal energy (200 J) was used in 85% of shocks. Electrical cardioversion immediately restored sinus rhythm in 102 sessions (71%). Pretreatment with amiodarone did not increase the success rates. During the follow-up, the percentages of sinus rhythm decreased from 43% after 1 hour to 23% after 24 hours. However, at ICU discharge, 54 patients (75%) were in sinus rhythm. Of the 54 patients in sinus rhythm, only 18 (33%) converted to sinus rhythm after repeated cardioversions, whereas the remaining 36 (66%) did so spontaneously or with amiodarone.

CONCLUSIONS

Biphasic electrical cardioversion in cardiosurgical ICU patients was immediately successful in restoring sinus rhythm in 71% of sessions. However, early relapse of atrial fibrillation was common in the 24-hour follow-up. At ICU discharge, the majority of patients were in sinus rhythm, but the efficacy of repetitive electrical cardioversion in restoring sinus rhythm was disappointing.

Shock Management for Cardio-surgical ICU Patients - The Golden Hours

Postoperative shock following cardiac surgery is a serious condition with a high morbidity and mortality. There are four types of shock: cardiogenic, hypovolemic, obstructive and distributive and these can occur alone or in combination. Early identification of the underlying diseases and understanding of the mechanisms at play are key for successful management of shock. Prompt resuscitation measures are necessary to reverse the shock state and avoid permanent organ dysfunction or death. In this review, the authors focus on the management during the first 6 hours of shock (the 'golden hours'). They discuss how to optimise preload, vascular tone, contractility, heart rate and oxygen delivery. The review incorporates the findings of recent trials on early goal-directed therapy and includes practical recommendations in areas in which the evidence is scare or controversial. While the review focuses on cardio-surgical patients, the suggested treatment algorithms might be usefully expanded to other critically ill patients with shock arising from other causes.

[Treatment of atrial fibrillation in intensive care units and emergency departments]

BACKGROUND

Atrial fibrillation is the most common arrhythmia in patients hospitalized in intensive care units and emergency departments and is associated with an increased morbidity and mortality. In critically ill patients, atrial fibrillation can cause hemodynamic instability and cardiogenic shock. The mechanisms and the management of atrial fibrillation are significantly different in critically ill patients compared to outpatients.

DIAGNOSIS AND TREATMENT

The initial management includes the evaluation of the hemodynamic consequences of new-onset atrial fibrillation and the optimization of reversible causes. In patients with hemodynamic instability the rapid restoration of an adequate perfusion pressure is the initial goal. Often, a rapid conversion in sinus rhythm is required to achieve hemodynamic stabilization. Electrical cardioversion, if possible performed after pretreatment with an antiarrhythmic drug to increase the success rate, frequently plays a central role in the conversion to sinus rhythm of hemodynamically unstable patients. Stable patients are initially treated with a short-acting intravenous β-blocker to achieve heart rate control. A conversion to sinus rhythm may be achieved pharmacologically with vernakalant, an atrial-specific multichannel blocker.

EVALUATION

All patients with atrial fibrillation lasting more than 48 h should be evaluated for anticoagulation in order to reduce cardio-embolic complications. After recovering from the acute illness, atrial fibrillation persists only in a minority of patients.

Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation

BACKGROUND

Atrial fibrillation is the most frequent sustained arrhythmia. Atrial fibrillation frequently recurs after restoration of normal sinus rhythm. Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear. This is an update of a review previously published in 2008 and 2012.

OBJECTIVES

To determine in patients who have recovered sinus rhythm after having atrial fibrillation, the effects of long-term treatment with antiarrhythmic drugs on death, stroke, embolism, drug adverse effects and recurrence of atrial fibrillation.

SEARCH METHODS

We updated the searches of CENTRAL in The Cochrane Library (2013, Issue 12 of 12), MEDLINE (to January 2014) and EMBASE (to January 2014). The reference lists of retrieved articles, recent reviews and meta-analyses were checked.

SELECTION CRITERIA

Two independent authors selected randomised controlled trials comparing any antiarrhythmic drug with a control (no treatment, placebo, drugs for rate control) or with another antiarrhythmic drug in adults who had atrial fibrillation and in whom sinus rhythm was restored. Post-operative atrial fibrillation was excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed quality and extracted data. Studies were pooled, if appropriate, using Peto odds ratio (OR). All results were calculated at one year of follow-up.

MAIN RESULTS

In this update three new studies, with 534 patients, were included making a total of 59 included studies comprising 21,305 patients. All included studies were randomised controlled trials. Allocation concealment was adequate in 17 trials, it was unclear in the remaining 42 trials. Risk of bias was assessed in all domains only in the trials included in this update.Compared with controls, class IA drugs quinidine and disopyramide (OR 2.39, 95% confidence interval (95% CI) 1.03 to 5.59, number needed to treat to harm (NNTH) 109, 95% CI 34 to 4985) and sotalol (OR 2.23, 95% CI 1.1 to 4.50, NNTH 169, 95% CI 60 to 2068) were associated with increased all-cause mortality. Other antiarrhythmics did not seem to modify mortality, but our data could be underpowered to detect mild increases in mortality for several of the drugs studied.Several class IA (disopyramide, quinidine), IC (flecainide, propafenone) and III (amiodarone, dofetilide, dronedarone, sotalol) drugs significantly reduced recurrence of atrial fibrillation (OR 0.19 to 0.70, number needed to treat to beneft (NNTB) 3 to 16). Beta-blockers (metoprolol) also significantly reduced atrial fibrillation recurrences (OR 0.62, 95% CI 0.44 to 0.88, NNTB 9).All analysed drugs increased withdrawals due to adverse affects and all but amiodarone, dronedarone and propafenone increased pro-arrhythmia. Only 11 trials reported data on stroke. None of them found any significant difference with the exception of a single trial than found less strokes in the group treated with dronedarone compared to placebo. This finding was not confirmed in others studies on dronedarone.We could not analyse heart failure and use of anticoagulation because few original studies reported on these measures.

AUTHORS' CONCLUSIONS

Several class IA, IC and III drugs, as well as class II drugs (beta-blockers), are moderately effective in maintaining sinus rhythm after conversion of atrial fibrillation. However, they increase adverse events, including pro-arrhythmia, and some of them (disopyramide, quinidine and sotalol) may increase mortality. Possible benefits on clinically relevant outcomes (stroke, embolism, heart failure) remain to be established.

Risk factors for atrial fibrillation recurrence: a literature review

Atrial fibrillation is the most common arrhythmia managed in clinical practice and it is associated with an increased risk of mortality, stroke and peripheral embolism. Unfortunately, the incidence of atrial fibrillation recurrence ranges from 40 to 50%, despite the attempts of electrical cardioversion and the administration of antiarrhythmic drugs. In this review, the literature data about predictors of atrial fibrillation recurrence are highlighted, with special regard to clinical, therapeutic, biochemical, ECG and echocardiographic parameters after electrical cardioversion and ablation. Identifying predictors of success in maintaining sinus rhythm after cardioversion or ablation may allow a better selection of patients to undergo these procedures. The aim is to reduce healthcare costs and avoid exposing patients to unnecessary procedures and related complications. Recurrent atrial fibrillation depends on a combination of several parameters and each patient should be individually assessed for such a risk of recurrence.

Management of atrial fibrillation in critically ill patients

Atrial fibrillation (AF) is common in ICU patients and is associated with a two- to fivefold increase in mortality. This paper provides a reappraisal of the management of AF with a special focus on critically ill patients with haemodynamic instability. AF can cause hypotension and heart failure with subsequent organ dysfunction. The underlying mechanisms are the loss of atrial contraction and the high ventricular rate. In unstable patients, sinus rhythm must be rapidly restored by synchronised electrical cardioversion (ECV). If pharmacological treatment is indicated, clinicians can choose between the rate control and the rhythm control strategy. The optimal substance should be selected depending on its potential adverse effects. A beta-1 antagonist with a very short half-life (e.g., esmolol) is an advantage for ICU patients because the effect of beta-blockade on cardiovascular stability is unpredictable in those patients. Amiodarone is commonly used in the ICU setting but has potentially severe cardiac and noncardiac side effects. Digoxin controls the ventricular response at rest, but its benefit decreases in the presence of adrenergic stress. Vernakalant converts new-onset AF to sinus rhythm in approximately 50% of patients, but data on its efficacy and safety in critically ill patients are lacking.

Contemporary approach to electrical and pharmacological cardioversion of atrial fibrillation

In patients with atrial fibrillation (AF), a rhythm-control strategy may be adopted when there are unacceptable symptoms from AF, failure of rate control, and/or the presence of comorbidities, such as heart failure, that may improve with restoration of sinus rhythm. When a rhythm-control strategy is chosen and the patient is in persistent AF, cardioversion will be necessary to convert the rhythm to sinus. Patients with AF present for > 48 hours must be effectively anticoagulated both prior to and after cardioversion. With newer oral anticoagulants, achieving effective anticoagulation is faster and more reliable, with no requirement for blood test monitoring. Cardioversion can be accomplished either electrically or pharmacologically, and in some cases, electrical cardioversion may be facilitated pharmacologically. Electrical cardioversion has a higher success rate compared with pharmacological cardioversion in the short-term. Pharmacological cardioversion is usually accomplished with intravenous ibutilide, oral flecainide or propafenone, or intravenous amiodarone. Oral amiodarone and dofetilide also result in chemical cardioversion in some patients over a longer period of time. Long-term success in the maintenance of sinus rhythm post-cardioversion can be increased with the use of antiarrhythmic drugs. Alternatively, when AF is recurrent and symptomatic despite the use of antiarrhythmic drugs, catheter ablation is a reasonable option for many patients. Cardioversion may be incorporated into the management approach of persistent AF when the primary therapeutic option chosen is catheter ablation.

Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most frequent sustained arrhythmia. AF recurs frequently after restoration of normal sinus rhythm. Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear.

OBJECTIVES

To determine, in patients who recovered sinus rhythm after AF, the effect of long-term treatment with antiarrhythmic drugs on death, stroke and embolism, adverse effects, pro-arrhythmia, and recurrence of AF.

SEARCH METHODS

We updated the searches of CENTRAL on The Cochrane Libary (Issue 1 of 4, 2010), MEDLINE (1950 to February 2010) and EMBASE (1966 to February 2010). The reference lists of retrieved articles, recent reviews and meta-analyses were checked.

SELECTION CRITERIA

Two independent reviewers selected randomised controlled trials comparing any antiarrhythmic with a control (no treatment, placebo or drugs for rate control) or with another antiarrhythmic, in adults who had AF and in whom sinus rhythm was restored. Post-operative AF was excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed quality and extracted data. Studies were pooled, if appropriate, using Peto odds ratio (OR). All results were calculated at one year of follow-up.

MAIN RESULTS

In this update, 11 new studies met inclusion criteria, making a total of 56 included studies, comprising 20,771 patients. Compared with controls, class IA drugs quinidine and disopyramide (OR 2.39, 95% confidence interval (95%CI) 1.03 to 5.59, number needed to harm (NNH) 109, 95%CI 34 to 4985) and sotalol (OR 2.47, 95%CI 1.2 to 5.05, NNH 166, 95%CI 61 to 1159) were associated with increased all-cause mortality. Other antiarrhythmics did not seem to modify mortality.Several class IA (disopyramide, quinidine), IC (flecainide, propafenone) and III (amiodarone, dofetilide, dronedarone, sotalol) drugs significantly reduced recurrence of AF (OR 0.19 to 0.70, number needed to treat (NNT) 3 to 16). Beta-blockers (metoprolol) also reduced significantly AF recurrence (OR 0.62, 95% CI 0.44 to 0.88, NNT 9).All analysed drugs increased withdrawals due to adverse affects and all but amiodarone, dronedarone and propafenone increased pro-arrhythmia. We could not analyse other outcomes because few original studies reported them.

AUTHORS' CONCLUSIONS

Several class IA, IC and III drugs, as well as class II (beta-blockers), are moderately effective in maintaining sinus rhythm after conversion of atrial fibrillation. However, they increase adverse events, including pro-arrhythmia, and some of them (disopyramide, quinidine and sotalol) may increase mortality. Possible benefits on clinically relevant outcomes (stroke, embolisms, heart failure) remain to be established.

Electrical and pharmacologic cardioversion for atrial fibrillation

In this article, electrical and pharmacologic cardioversion for atrial fibrillation is described in detail. Indications for cardioversion and management of pericardioversion anticoagulation also are discussed. Finally, management strategies for immediate recurrence of atrial fibrillation and cardioversion failure are offered.

Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most frequent sustained arrhythmia. After restoration of normal sinus rhythm, the recurrence rate of AF is high. Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear.

OBJECTIVES

To determine, in patients who recovered sinus rhythm after AF, the effect of long-term treatment with antiarrhythmic drugs on death, stroke and embolism, adverse effects, pro-arrhythmia and recurrence of AF. If several antiarrhythmics were effective our secondary aim was to compare them.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Libary (Issue 2, 2005), MEDLINE (1950 to May 2005) and EMBASE (1966 to May 2005) were searched. The reference lists of retrieved articles, recent reviews and meta-analyses were checked. No language restrictions were applied.

SELECTION CRITERIA

Two independent reviewers selected randomised controlled trials comparing any antiarrhythmic with a control (no treatment, placebo or drugs for rate control) or with another antiarrhythmic, in adults who had AF and in whom sinus rhythm was restored. Post-operative AF was excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed quality and extracted data, on an intention-to-treat basis. Disagreements were resolved by discussion. Studies were pooled, if appropriate, using Peto odds ratio (OR).

MAIN RESULTS

45 studies met inclusion criteria, comprising 12,559 patients. All results were calculated at 1 year of follow-up. Class IA drugs (disopyramide, quinidine) were associated with increased mortality compared with controls (OR 2.39, 95% confidence interval (CI) 1.03 to 5.59, P = 0.04, number needed to harm (NNH) 109, 95% CI 34 to 4985). Other antiarrhythmics did not modify mortality. Several class IA (disopyramide, quinidine), IC (flecainide, propafenone) and III (amiodarone, dofetilide, dronedarone, sotalol) drugs significantly reduced recurrence of AF (OR 0.19 to 0.60, number needed to treat 2 to 9), but all increased withdrawals due to adverse affects (NNH 17 to 36) and all but amiodarone and propafenone increased pro-arrhythmia (NNH 17 to 119).

AUTHORS' CONCLUSIONS

Several class IA, IC and III drugs are effective in maintaining sinus rhythm but increase adverse events, including pro-arrhythmia, and disopyramide and quinidine are associated with increased mortality. Any benefit on clinically relevant outcomes (embolisms, heart failure, mortality) remains to be established.

A written policy increases compliance with guidelines for therapeutic anticoagulation prior to elective direct current cardioversion of atrial fibrillation

BACKGROUND

Therapeutic anticoagulation before elective direct current cardioversion (DCC) of atrial fibrillation reduces the risk of embolic stroke. Direct current cardioversion is performed by a variety of practitioners, and variable adherence to preprocedural anticoagulation guidelines is common.

OBJECTIVE

We assessed the impact of a written policy on guideline compliance.

METHODS

: Anticoagulation status and transesophageal echocardiogram (TEE) results were reviewed in 55 patients (32 men/23 women; ages 18-83 years) who underwent elective DCC during the 6-month period before a written anticoagulation policy was sent to physicians who perform, prepare, or refer patients for this procedure. The nurse assigned to each DCC was responsible for documenting anticoagulation status. In accordance with guidelines, therapeutic anticoagulation was defined as a normalized ratio range > or = 2.0 for at least 3 weeks or a negative TEE with a normalized ratio range > or = 2.0 or a partial thromboplastin time > 50 seconds at the time of DCC. Immediately after policy implementation, anticoagulation status and TEE results were reviewed in 53 patients (42 men/11 women; ages 21-84 years) and 1 year post-policy implementation.

RESULTS

Before policy implementation, 14 of 52 patients (27%) had DCC performed without adequate anticoagulation or a negative TEE. Immediately postimplementation, only 2 of 50 patients (4%) had DCC performed without adequate anticoagulation or a negative TEE (P = .002). One year post-policy implementation, only 4 of 48 patients (8%) had DCC performed without adequate anticoagulation or a negative TEE (P = .03).

CONCLUSIONS

Implementing a written policy greatly reduces the number of patients undergoing DCC without adequate anticoagulation or a negative TEE. The impact of this intervention was quickly demonstrable and persisted during follow-up. Supplementing published recommendations with guideline-driven policies may reduce variations in clinical practice and improve quality of care.

Atrial premature complexes and heart rate have prognostic significance in 1-month atrial fibrillation recurrence after electrical cardioversion

AIMS

The aim of this study was to investigate the significance of simple 24-h Holter (24H) data after electrical cardioversion (CV) for atrial fibrillation (AF) recurrence.

METHODS

We prospectively studied 47 consecutive patients subjected to CV, who successfully converted to sinus rhythm. All underwent echocardiography and 24H after CV. AF recurrence was studied at 14 days and 1 month by second 24H or by interim report of AF.

RESULTS

About 53.2% remained in sinus rhythm (group I) and the rest recurred to AF (group II). Group I had fewer atrial premature complexes per hour (APC/h) (P = 0.002) and lower maximum (max HR), average, and minimum heart rates compared with group II (all Ps < 0.05). The optimal value of APC/h and max HR with best sensitivity and specificity was 32 APC/h and 90 bpm, respectively. These findings were the predictors of AF recurrence [hazard ratio (HR) = 4.5 with 95% CI = 1.7-11.7 and HR = 4.3 with 95% CI = 1.7-10.9, respectively]. Patients with the combination of both predictors had greater HR of AF recurrence compared with those with < 32 APC/h and max HR < 90 bpm (HR = 8.8 with 95% CI = 2.5-31.4).

CONCLUSION

Patients with frequent APC/h and high max HR are at high risk for 1-month AF recurrence after electrical CV.

Can atrial fibrillation with a coarse electrocardiographic appearance be treated with catheter ablation of the tricuspid valve-inferior vena cava isthmus? Results of a multicentre randomised controlled trial

OBJECTIVE

To see if strategy of ablating the tricuspid annulus-inferior vena cava isthmus (TV-IVC) is superior to electrical cardioversion to prevent recurrences in patients with coarse atrial fibrillation.

DESIGN

Prospective randomised controlled multicentre study.

SETTING

Four tertiary referral hospitals in the UK.

PATIENTS

57 patients with persistent coarse atrial fibrillation (irregular P waves > or =0.15 mV in > or =1 ECG lead).

INTERVENTIONS

Patients were randomised to receive external cardioversion (group A, n = 30) or TV-IVC ablation +/- DC cardioversion (group B, n = 27).

MAIN OUTCOME MEASURES

Cardiac rhythm, scores on quality of life and symptom questionnaires were assessed at 4, 16 and 52 weeks after the procedure.

RESULTS

20 (67%) patients in group A and 19 (70%) patients in group B were in sinus rhythm immediately after their index procedure. At 4, 16 and 52 weeks, the number of patients in sinus rhythm were 5, 3 and 2 in group A and 3, 3 and 1 in group B (p = NS). The quality of life and symptom questionnaire scores were similar in the two groups at each period of follow-up, although they were significantly better for sinus rhythm than for atrial fibrillation at each follow-up visit.

CONCLUSIONS

As a first-line strategy, TV-IVC ablation offers no advantages over direct current cardioversion for the management of coarse atrial fibrillation.

The outcome of Direct Current Cardioversion (DCC) for the treatment of Atrial Fibrillation (AF) in a district general hospital in Ireland

BACKGROUND

Direct current cardioversion (DCC) is a method to control persistent AF, to facilitate a reduction in stroke risk. Although this is a frequently performed procedure, there are no available published data regarding its outcome in an Irish setting.

AIMS

To determine the short- and long-term outcome of DCC, factors predicting a successful outcome, and its safety.

METHODS

Data relating to each DCC were collected retrospectively from patient notes over a 6.3 year-period, and subsequently entered into a Microsoft Access database before subsequent statistical analysis.

RESULTS

Forty-five consecutive unselected patients were identified, in which 59 DCCs were performed. Sinus rhythm (SR) was achieved immediately after DCC in 54/59 (91%) patients. There was a significant positive correlation between patient body weight and the energy level required to achieve SR (p=0.0001). No thromboembolic complications were noted. After a mean follow-up time of 12 +/- 13.7months, 30/45 (67%) had maintained SR. After univariate analysis, a number of important factors predictive of maintenance of SR at follow-up were identified.

CONCLUSION

DCC was found to be an effective method for short- and long-term control of AF, without thromboembolic complications, and patients with a favourable long-term outcome after DCC could conceivably be predicted on the basis of a methodical history, careful examination, simple investigations and pharmacological variables.

Cardiovascular Emergencies in the Elderly

Already the major cause of mortality in the United States, cardio-vascular emergencies will become increasingly prevalent in the future as the geriatric population doubles. This article discusses five cardiovascular emergencies: acute coronary syndrome, congestive heart failure, dysrythmias, aortic dissection, and ruptured abdominal aortic aneurysm. The discussion focuses on the differences in presentation, management, and outcomes that characterize each disease amongst the elderly. As a rule, the elderly have significantly worse outcomes than younger patients.

Serial antiarrhythmic therapy: role of amiodarone in prevention of atrial fibrillation recurrence--a lesson from the HOT CAFE Polish Study

Antiarrhythmic drug prophylaxis is known to improve long-term success of electrical cardioversion (CV) in persistent atrial fibrillation (AF). This prospective study evaluates the efficacy of sequential antiarrhythmic drug therapy in sinus rhythm (SR) maintenance after successful elective CV in patients with persistent nonvalvular AF.

MATERIALS AND METHODS

One hundred and twenty-eight patients (61+/-8 years old) with persistent AF underwent CV. Mean AF duration preceding CV was 268+/-99 days. Following SR restoration, patients were treated sequentially with either of the following antiarrhythmic drugs: propafenone, sotalol or disopyramide. Where arrhythmia recurred, patients received another CV and a new drug from the range defined above. Where such treatment failed, patients were loaded with 14.0- to 16.0-gram doses of amiodarone and a third CV was performed. If the first CV failed to restore SR, patients received a loading dose of amiodarone followed by another CV. When successful, amiodarone was administered on continuous basis.

RESULTS

The first CV proved successful in 55.5% of patients. During 1-year of follow-up, 31 patients (43.7%) presented with SR were treated with one antiarrhythmic agent (median does not exist). Application of the second drug proved to be effective in 6 patients (15.0%; median 13 days). Amiodarone was administered as the third antiarrhythmic agent to patients who had AF recurrence on the first two antiarrhythmic agents (propafenone, sotalol or disopyramide). It proved to be effective in 18 patients (52.9%; median does not exist) remaining free from AF for a period of 1 year as of commencement of the sequential antiarrhythmic therapy. Fifty-seven patients, in whom the first CV was ineffective, received amiodarone. During the loading period, SR was restored in 7 patients (12.3%). The remaining 50 patients underwent repeated CV, with SR restored in 37 (74.0%) of them. Long-term amiodarone treatment maintained SR in 30 (68.2%) patients during the follow-up period. Amiodarone helped to maintain SR in a total of 56.5% of patients.

CONCLUSIONS

Amiodarone seems to be the drug most effectively restoring and maintaining SR in patients with persistent AF resistant to CV and standard antiarrhythmic drug prophylaxis.

Pharmacological cardioversion of atrial fibrillation: current management and treatment options

Atrial fibrillation (AF) is the most common form of arrhythmia, carrying high social costs. It is usually first seen by general practitioners or in emergency departments. Despite the availability of consensus guidelines, considerable variations exist in treatment practice, especially outside specialised cardiological settings. Cardioversion to sinus rhythm aims to: (i) restore the atrial contribution to ventricular filling/output; (ii) regularise ventricular rate; and (iii) interrupt atrial remodelling. Cardioversion always requires careful assessment of potential proarrhythmic and thromboembolic risks, and this translates into the need to personalise treatment decisions. Among the many clinical variables that affect strategy selection, time from onset is crucial. In selected patients, pharmacological cardioversion of recent-onset AF can be a safely used, feasible and effective approach, even in internal medicine and emergency departments. In most cases of recent-onset AF, pharmacological cardioversion provides an important--and probably more cost effective--alternative to electrical cardioversion, which can then be employed as a second-line therapy for nonresponders. Class IC agents (flecainide or propafenone), which can be safely used in hospitalised patients with recent-onset AF without left ventricular dysfunction, can provide rapid conversion to sinus rhythm after either intravenous administration or oral loading. Although intravenous amiodarone requires longer conversion times, it is still the standard treatment for patients with heart failure. Ibutilide also provides good conversion rates and could be used for AF patients with left ventricular dysfunction (were it not for high costs). For long-lasting AF most pharmacological treatments have only limited efficacy and electrical cardioversion remains the gold standard in this setting. However, a widely used strategy involves pretreatment with amiodarone in the weeks before planned electrical cardioversion: this provides optimal prophylaxis and can sometimes even restore sinus rhythm. Dofetilide may also be capable of restoring sinus rhythm in up to 25-30% of patients and can be used in patients with heart failure. The potential risk of proarrhythmia increases the need for careful therapeutic decision making and management of pharmacological cardioversion. The results of recent trials (AFFIRM [Atrial Fibrillation Follow-up Investigation of Rhythm Management] and RACE [Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation]) on rate versus rhythm control strategies in the long term have led to a generalised shift in interest towards rate control. Although carefully designed studies are required to better define the role of pharmacological rhythm control in specific AF settings, this alternative option remains a recommendable strategy for many patients, especially those in acute care.

Atrial fibrillation in the heart failure population

Atrial fibrillation (AF) is the most common chronic arrhythmia. Incidence of AF in the heart failure population is high--10% to 30%--and is associated with a reduction in exercise capacity and a poor long-term prognosis. Management of AF includes 4 strategies: control of heart rate, termination of AF/conversion back to sinus rhythm, prevention of recurrences, and prevention of thromboembolic events. This article reviews these management strategies in the heart failure population.

Pharmacologic reversion of persistent atrial fibrillation with amiodarone predicts long-term sinus rhythm maintenance

OBJECTIVE

The study analyzed the role of different variables that determine long-term sinus rhythm maintenance in patients with persistent atrial fibrillation who are treated with amiodarone.

BACKGROUND

It has been recognized that different factors influence long-term sinus rhythm preservation after the conversion of persistent atrial fibrillation. Although the duration of the arrhythmia appears to be the most important factor, consistent information regarding the role of the mode of arrhythmia conversion (pharmacologic or electric) is still lacking.

METHODS

One hundred and forty one anticoagulated patients with persistent atrial fibrillation (median duration 8 months, percentiles 25 and 75: 2-24) were treated for 4 weeks with oral amiodarone (600 mg/day). Those in whom the arrhythmia persisted underwent electric cardioversion. After restoration of normal sinus rhythm (either pharmacologic or electric), all patients received a daily dose of amiodarone (200 mg) and were followed for a median of 19 months (percentiles 25 and 75: 8-34 months).

RESULTS

Sixty eight patients (48.22%) regained sinus rhythm during the initial period of amiodarone treatment with 600 mg/day (Group I) and 73 (51.78%) required electric cardioversion (Group II). During the entire follow-up, atrial fibrillation relapsed in 63 patients: 17 (25%) in Group I and 46 (63%) in Group II. Recurrences of the arrhythmia were strikingly less frequent in patients whose atrial fibrillation lasted 12 months or less (33/103, 32.3%) than in those whose atrial fibrillation lasted more than 12 months (30/38, 78.94%). In the multivariate analysis, the mode of reversion (HR, 0.37; CI, 0.21-0.65) and the duration of the arrhythmia (HR, 2.55; CI, 1.54-4.20) were the determinants for long-term sinus rhythm maintenance. Age, sex, left atrium size, left ventricle diameter, and the shortening fraction did not significantly influence the rate of arrhythmia recurrence. Among the 141 patients included in the study, 113 patients were followed for at least 1 year, and cardiac rhythm was assessed at this time. Of these, only 1 of 48 patients (2.1%) in Group I was in atrial fibrillation, in marked contrast with 18 of 65 patients (27.8%) in Group II (RR, 0.075; 95% CI, 0.01-0.54).

CONCLUSIONS

In patients with persistent atrial fibrillation, long-term preservation of sinus rhythm under chronic amiodarone treatment may be anticipated when the arrhythmia lasts 12 months or less and/or its reversion is obtained pharmacologically. We may confidently assume that these two factors have a beneficial additive influence on the outcome.

[External electrical cardioversion of atrial arrhythmia: predictive criteria of success]

AIM

Supraventricular arrhythmia is a major public health problem because of its prevalence and clinical consequences. The first step of the treatment usually consists in restoring sinusal rhythm. The aim of this study is to evaluate results and predictive factors of success of electrical cardioversion.

METHODS

We studied a series of 143 consecutive electric cardioversion preformed in 131 French patients.

RESULTS

The rate of successful direct current cardioversion was 91.2%. Negative predictive factors are the height body mass index and the age of arrhythmia. Atrial flutter is a predictive factor of success. These results agree with published results. Our study highlights the interest of some nonantiarrhythmic drugs received by the patient during the period before the direct current cardioversion. Thus, a spironolactone treatment appears to be a new predictive factor of the success of electrical cardioversion (success in patients treated with spironolactone: 100% vs 89% without, P = 0.04).

CONCLUSIONS

Our results agree with usual predictive factors of the success of cardioversion. Nevertheless, a new approach is that of the positive effect of spironolactone on cardioversion. A prospective randomized study is necessary to confirm this result.

Current management of symptomatic atrial fibrillation

Atrial fibrillation (AF) is the commonest arrhythmia. It presents in distinct patterns of paroxysmal, persistent and chronic AF, and patient management aims differ according to the pattern. In paroxysmal AF, drug treatment with beta-blockers, class Ic and class III agents reduce the frequency and duration of episodes. In persistent AF (recent onset, non-paroxysmal), early cardioversion with either pharmacological agents or by direct current (DC) cardioversion should be actively considered, in those patients who are suitable. Patients most likely to cardiovert and remain in sinus rhythm include those with duration of AF of <1 year, an acute reversible cause, left atrial diameter <50 mm and good left ventricular function on echocardiography. Recent data show that maintenance of sinus rhythm after successful cardioversion is enhanced by the use of class III drugs including amiodarone and dofetilide. In chronic or permanent AF, management is aimed at controlling the ventricular rate response with combinations of digoxin, beta-blockers and calcium antagonists with atrio-ventricular nodal activity (diltiazem and verapamil). There is some debate about the prognostic significance of AF. Certainly AF is associated with an excess mortality but this is largely accounted for by its association with serious intrinsic heart disease and the thrombo-embolic complications of the arrhythmia. Atrial fibrillation is a common default arrhythmia for the sick heart.

Efficacy of amiodarone for the termination of chronic atrial fibrillation and maintenance of normal sinus rhythm: a prospective, multicenter, randomized, controlled, double blind trial

OBJECTIVE

We sought to assess the efficacy and safety of amiodarone for restoration and maintenance of sinus rhythm in patients with chronic atrial fibrillation in a prospective, randomized, double blind trial.

BACKGROUND

Restoration and preservation of sinus rhythm is difficult in patients with chronic atrial fibrillation. The efficacy of oral amiodarone has not been conclusively established.

METHODS

Ninety-five patients with chronic atrial fibrillation, lasting an average of 35.6 months, were randomized to either amiodarone (600 mg/d) (47 patients) or placebo (48 patients) during four weeks. Nonresponders underwent electric cardioversion, and those who reverted continued with amiodarone (200 mg/d) or placebo. End-points were successful cardioversion and sinus rhythm maintenance.

RESULTS

Sixteen patients (34.04%) in the amiodarone group reverted within 27.28 +/- 8.85 days in comparison with 0% in the placebo group (P < 0.000009). The conversion rate rose to 51.72% in patients with chronic atrial fibrillation lasting less than 12 months. Twenty-eight patients in the amiodarone group and 39 in the placebo group underwent electric cardioversion, which was successful in 19 patients (67.8%) of the amiodarone group and in 15 (38.46%) of the placebo group (P = 0.017). Altogether, conversion was obtained in 79.54% of the amiodarone group patients and in 38.46% of the placebo group patients (P < 0.0001). During follow-up, atrial fibrillation relapsed in 13 (37.14%) of 35 patients of the amiodarone group within 8.84 +/- 8.57 months and in 12 (80%; P = 0.009) of 15 patients of the placebo group within 2.74 +/- 3.41 months.

CONCLUSIONS

Oral amiodarone restored sinus rhythm in one third of patients with chronic atrial fibrillation, increased the success rate of electric cardioversion, decreased the number of relapses and delayed their occurrence.

Cost effectiveness of therapies for atrial fibrillation. A review

Atrial fibrillation is the most common supraventricular tachyarrhythmia encountered in clinical practice, affecting over 5% of persons over the age of 65 years. A common pathophysiological mechanism for arrhythmia development is atrial distention and fibrosis induced by hypertension, coronary artery disease or ventricular dysfunction. Less frequently, atrial fibrillation is caused by mitral stenosis or other provocative factors such as thyrotoxicosis, pericarditis or alcohol intoxication. Depending on the extent of associated cardiovascular disease, atrial fibrillation may produce haemodynamic compromise, or symptoms such as palpitations, fatigue, chest pain or dyspnoea. Arrhythmia-induced atrial stasis can precipitate clot formation and the potential for subsequent thromboembolism. Comprehensive management of atrial fibrillation requires a multifaceted approach directed at controlling symptoms, protecting the patient from ischaemic stroke or peripheral embolism and possible conversion to or maintenance of sinus rhythm. Numerous randomised trials have demonstrated the efficacy of warfarin--and less so aspirin (acetylsalicylic acid)--in reducing the risk of embolic events. Furthermore, therapeutic strategies exist that can favourably modify symptoms by restoring and maintaining sinus rhythm with cardioversion and antiarrhythmic prophylaxis. However, the risks and benefits of various treatments is highly dependent on patient-specific features, emphasising the need for an individualised approach. This article reviews the findings of cost-effectiveness studies published over the past decade that have evaluated different components of treatment strategies for atrial fibrillation. These studies demonstrate the economic attractiveness of acute management options, long term warfarin prophylaxis, telemetry-guided initiation of antiarrhythmic therapy, approaches to restore and maintain sinus rhythm, and the potential role of transoesophageal echocardiographic screening for atrial thrombus prior to pharmacological or electrical cardioversion. Further, we discuss the merits and limitations of the cost-effectiveness analyses in the context of overall treatment strategies. Finally, we identify areas that will require additional research to achieve the goal of effective and economically efficient management of atrial fibrillation.

Effects of diltiazem pretreatment on direct-current cardioversion in patients with persistent atrial fibrillation: a single-blind, randomized, controlled study

BACKGROUND

Electric conversion of atrial fibrillation is the most widely used and effective treatment for sinus rhythm restoration. However, it has a limited success rate and a high recurrence rate.

HYPOTHESIS

Pretreatment with calcium channel blocker may improve the efficacy by reversing the so-called "electric remodeling" phenomenon, also related to overload in cytosolic calcium.

METHODS

The efficacy of diltiazem or amiodarone pretreatment (oral, 1 month before and 1 month after conversion) on direct-current conversion of persistent atrial fibrillation was assessed in 120 patients, randomly assigned to 3 matched groups: A (n = 44, diltiazem); B (n = 46, amiodarone), and C (n = 30, digoxin).

RESULTS

Before electric conversion, all treatments significantly decreased mean heart rate. Spontaneous conversion to sinus rhythm was achieved in 6% of patients of group A (3 of 46) versus 25% of group B (11 of 44) and 3% (1 of 30) of group C (A/C vs B, P < .005). Current conversion was more successful in group B (91%) compared with group A (76%) and group C (67%) (B vs A/C, P < .05), with no difference in the electric threshold for effective conversion (P = not significant). At the 24-hour time point, early relapse of atrial fibrillation was similar between groups A and B (A, 2%; B, 3%; P = not significant) and lower than group C (12%) (P < .01), whereas at the 1-month time point the recurrence rate was lower in group B (28%) versus groups A (56%) and C (78%) (B vs A/C, P < .01). No significant side effects were reported.

CONCLUSIONS

Although diltiazem seems to be as effective as amiodarone in reducing early atrial fibrillation recurrences, diltiazem is less effective in determining spontaneous or electric conversion, with a higher recurrence rate at 2 months. Diltiazem pretreatment could be considered as only a second choice treatment in those patients in whom amiodarone is contraindicated.

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.