Controlled trial of a long-acting quinidine for maintenance of sinus rhythm after conversion of sustained atrial fibrillation

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.

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.

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.

Quinidine for pharmacological cardioversion of atrial fibrillation: a retrospective analysis in 501 consecutive patients

BACKGROUND

Although quinidine has been used to terminate atrial fibrillation (AFib) for a long time, it has been recently classified to be used as a third-line-drug for cardioversion. However, these recommendations are based on a few small studies, and there are no data available of a larger modern patient population undergoing pharmacological cardioversion of AFib. Therefore, we evaluated the safety of quinidine for cardioversion of paroxysmal AFib in patients after cardiac surgery and coronary intervention.

METHODS

In 501 consecutive patients (66 +/- 9 years, 32% women), 200-400 mg of quinidine were administered every 6 hours until cardioversion or for a maximum of 48 hours. Patients were included with QT interval < or =450 ms, ejection fraction (EF) > or =35%, and plasma potassium >4.3 mEq/L. Exclusion criteria were: unstable angina, myocardial infarction <3 months, and advanced congestive heart failure. Patients received verapamil, beta-blockers, or digitalis to slow down ventricular rate <100 bpm.

RESULTS

Quinidine therapy did not have to be stopped due to adverse drug reactions (ADR), and no significant QTc interval prolongation (Bazett and Fridericia correction) and no life-threatening ventricular arrhythmia occurred. Mean quinidine dose was 617 +/- 520 mg and 92% of the patients received verapamil or beta-blocker to decrease ventricular rate. Cardioversion was successful in 84% of patients. All ADRs were minor and transient. Multivariate analysis revealed female gender (OR 2.62, CI 1.61-4.26, P < 0.001) and EF 45-54% (OR 1.97, CI 1.15-3.36, P = 0.013) as independent risk factors for ADRs.

CONCLUSIONS

Quinidine for pharmacological cardioversion of AFib is safe and well tolerated in this subset of patients.

Long-term management of atrial fibrillation

In the past decade, catheter ablation techniques and implantable devices have revolutionized the treatment of ventricular arrhythmias, junctional arrhythmias, and atrial flutter. For most patients presenting with atrial fibrillation (AF), the treatment available today is similar to that used a century ago, although nonpharmacologic strategies of therapy have begun to emerge for selected cases. There have been important recent advances in our understanding of the pathophysiology of AF and its complications, and it may be possible to improve patient management by refinement of the way in which current drugs are used.

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.

Meta-analysis of randomised controlled trials of the effectiveness of antiarrhythmic agents at promoting sinus rhythm in patients with atrial fibrillation

OBJECTIVE

To conduct a meta-analysis of randomised controlled trials to estimate the effectiveness of antiarrhythmic drugs at promoting sinus rhythm in patients with atrial fibrillation.

DESIGN

Articles were identified by using a comprehensive search of English language papers indexed in Medline from 1966 to August 2001. For the outcomes of sinus rhythm and death, a random effects model was used to model repeated assessments within a study at different time points.

SETTING

Emergency departments and ambulatory clinics.

PATIENTS

Patients with atrial fibrillation.

INTERVENTIONS

Antiarrhythmic agents grouped according to their Vaughan-Williams class.

MAIN OUTCOME MEASURES

Sinus rhythm and mortality.

RESULTS

91 articles met a priori criteria for inclusion in the analysis. Median duration of follow up was one day (range 0.04-1096, mean (SD) 46 (136) days). The median proportion of patients in sinus rhythm at follow up was 55% (range 0-100%) and 32% (range 0-90%) receiving active treatment and placebo, respectively. Median survival was 99% (range 55-100%) and 99% (range 55-100%). Compared with placebo, the following drug classes were associated with increased sinus rhythm at follow up: IA (treatment difference 21.5%, 95% confidence interval (CI) 16.3% to 26.8%); IC (treatment difference 33.1%, 95% CI 23.3% to 42.9%); and III (treatment difference 17.4%, 95% CI 11.5% to 23.3%). Class IC drugs were associated with increased sinus rhythm at follow up compared with class IV drugs (treatment difference 43.2%, 95% CI 11.5% to 75.0%). There was no significant difference in mortality between any drug classes.

CONCLUSIONS

Class IA, IC, and III drugs are associated with increased sinus rhythm at follow up compared with placebo. It is unclear whether any antiarrhythmic drug class is associated with increased or decreased mortality.

Antiarrhythmic effects of azimilide in atrial fibrillation: efficacy and dose-response. Azimilide Supraventricular Arrhythmia Program 3 (SVA-3) Investigators

OBJECTIVES

The purpose of this study was to assess the effectiveness of azimilide, a class III antiarrhythmic drug, in reducing the frequency of symptomatic arrhythmia recurrences in patients with atrial fibrillation, atrial flutter or both.

BACKGROUND

Atrial fibrillation is an increasingly common disorder of the heart rhythm, and most patients with this problem are identified because they have symptoms associated with their arrhythmia. New antiarrhythmic therapies are needed to treat patients with this problem.

METHODS

A total of 384 patients with a history of atrial fibrillation, atrial flutter or both were randomly assigned to receive once daily doses of placebo or azimilide; recurrent symptomatic arrhythmias were documented using transtelephonic electrocardiogram (ECG) recording. Azimilide 50 mg, 100 mg or 125 mg was tested; the primary efficacy analysis compared the time to first symptomatic recurrence in the combined azimilide 100 mg and 125 mg dose groups with that in the placebo group using the log-rank test.

RESULTS

In the primary efficacy analysis, the time to first symptomatic arrhythmia recurrence was significantly prolonged in the combined azimilide 100 mg and 125 mg daily dose group compared with the placebo group (chi-square 7.96, p = 0.005); the hazard ratio (placebo: azimilide) for this comparison was 1.58 (95% confidence interval [CI] = 1.15, 2.16). In comparisons between individual doses and placebo, the hazard ratio for the 50 mg daily dose was 1.17 (95% CI = 0.83, 1.66; p = 0.37); for the 100 mg group, dose was 1.38 (95% CI = 0.96, 1.98; p = 0.08), and for the 125 mg group, dose was 1.83 (95% CI = 1.24, 2.70; p = 0.002).

CONCLUSIONS

Azimilide significantly lengthened the symptomatic arrhythmia-free interval in patients with a history of atrial fibrillation, atrial flutter or both.

Use of metoprolol CR/XL to maintain sinus rhythm after conversion from persistent atrial fibrillation: a randomized, double-blind, placebo-controlled study

OBJECTIVES

The primary objective of the present study was to assess the efficacy of metoprolol CR/XL to reduce the risk of relapse after cardioversion of persistent atrial fibrillation to sinus rhythm.

BACKGROUND

Indirect data from studies with d,l sotalol provide evidence that the beta-blocking effects of the compound are important in maintaining sinus rhythm after cardioversion of atrial fibrillation.

METHODS

After successful conversion to sinus rhythm, 394 patients with a history of persistent atrial fibrillation were randomly assigned to treatment with metoprolol CR/XL or placebo. The two treatment groups were similar with respect to all pretreatment characteristics. Patients were seen on an outpatient basis for recording of resting electrocardiogram (ECG) after one week, one, three and six months of follow-up or whenever they felt that they had a relapse into atrial fibrillation or experienced an adverse event.

RESULTS

In the metoprolol CR/XL group, 96 patients (48.7%) had a relapse into atrial fibrillation compared with 118 patients (59.9%) in the placebo group (p = 0.005). Heart rate in patients after a relapse into atrial fibrillation was significantly lower in the metoprolol group (98 +/- 23 beats/min) than in the placebo group (107 +/- 27 beats/min). The rate of adverse events reported was similar in both groups when the difference in follow-up time was taken into account.

CONCLUSIONS

The results of this double-blind, placebo-controlled study in patients after cardioversion of persistent atrial fibrillation showed that metoprolol CR/XL was effective in preventing relapse into atrial fibrillation or flutter.

Appropriate outcome measures in trials evaluating treatment of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a widespread disease that has only recently received the focused attention of arrhythmia specialists despite being the most frequently occurring significant cardiac arrhythmia.

METHODS AND RESULTS

The wide variety of trial designs used to evaluate AF treatment is a reflection of the diverse outcomes associated with this condition. The best trials assess the impact of treatment on a clearly measured outcome that is of clinical relevance to patients. This review discusses the different designs of AF treatment trials and analyzes the utility of the various outcomes that can be assessed.

CONCLUSIONS

A sensible goal of AF treatment is to reduce the frequency of recurrences and to prolong the time between them. The most appropriate trials focus on AF recurrences that are symptomatic and therefore relevant to the patient. We still do not know if there is value in AF prevention, beyond preventing symptoms. However, ongoing and future studies will show whether AF suppression reduces the longer-term risks of stroke or death and improves patient quality of life. Cost of care will increasingly be studied in future trials of AF management.

Comparison of sotalol versus quinidine for maintenance of normal sinus rhythm in patients with chronic atrial fibrillation

Many clinicians choose sotalol for the prevention of recurrences of atrial fibrillation (AF) as an alternative to quinidine, which has been associated with an increase in long-term mortality. Using meta-analytic techniques, we compared the effects on maintenance of sinus rhythm and mortality of combined groups of patients with chronic AF treated with sotalol, quinidine, or a control drug. Rates of conversion at 6 months and mortality were combined for each group after performing sensitivity analysis to test for homogeneity. Bayesian estimates and corresponding 95% credibility intervals were constructed to compare the probabilities of achieving sinus rhythm and mortality among groups. A literature search revealed 4 sotalol studies, 6 quinidine studies, and 5 control studies that met inclusion criteria established a priori. The point estimates for maintaining normal sinus rhythm (at 6 months) and corresponding credibility intervals for the 3 groups were sotalol 50% (range 42% to 58%), quinidine 53% (range 48% to 59%), and control 32% (range 26% to 39%). When combining and comparing mortality effects, the following studies met the same inclusion criteria: 4 sotalol studies, 9 quinidine studies, and 7 control studies. The point estimates and corresponding credibility intervals for mortality in the 3 groups were sotalol 2.2% (range 0.6% to 4.8%), quinidine 3.0% (range 1.7% to 4.7%), and control 1.1% (range 0.3% to 2.4%). Sotalol and quinidine are comparable in their ability to maintain sinus rhythm at 6 months (about 50%) and both agents are superior to control. There is a trend for both agents to increase mortality with long-term therapy. These data do not support choosing sotalol over quinidine as a safer alternative for preventing recurrences of chronic AF.

Characterization of different subsets of atrial fibrillation in general practice in France: the ALFA study. The College of French Cardiologists

BACKGROUND

The clinical presentation and causes of atrial fibrillation (AF) in the 1990s may differ from AF seen 2 to 3 decades ago. It was the objective of this prospective study to characterize various clinical presentations and underlying conditions of patients with AF observed in general practice in France.

METHODS AND RESULTS

The study population comprised 756 patients (19 to 95 years of age) with electrocardiographically documented AF subdivided into paroxysmal (<7 days), chronic (last episode >1 month) and recent onset AF(persistent >7 days and<1 month). Symptoms were present in 670 patients (88.6%). The relative prevalences of paroxysmal, chronic, and recent onset AF were 22.1%, 51.4%, and 26.4%, respectively. Cardiac disorders, present in 534 patients (70.6%), included hypertension (39.4%), coronary artery disease (16.6%), and myocardial diseases (15.3%) as the most common. Rheumatic valvular disease represented a common cause in women (25. 0%) but not in men (8.0%). The paroxysmal group differed by a high percentage of palpitations (79.0%) and a low percentage of underlying heart disease (53.9%). With a mean follow-up of 8.6+/-3.7 months, 28 patients (3.7%) died, including 6 fatal cerebrovascular accidents. Among the 728 patients who survived, congestive heart failure occurred in 30 patients (4.1%), and embolic complications occurred in 13 patients (1.8%). In the paroxysmal AF group, 13 patients (8.0%) developed chronic AF and 51 (31.3%) had AF recurrences. At the time of follow-up, 53 patients (14.3%) from the chronic AF group and 108 patients (55.7%) from the recent onset AF group were in sinus rhythm.

CONCLUSIONS

This large-scale study establishes the current demographic profile of out-of-hospital patients with AF and highlights some of the changes that have occurred in the past decades, including a particular shift in cardiac causes toward nonrheumatic AF. This study also demonstrates significant differences between various subsets of AF.

Optimal management with Class I and Class III antiarrhythmic drugs should be done in the outpatient setting: protagonist

It has been suggested that patients be admitted for the initiation of Class I and Class III antiarrhythmic drugs to avoid serious proarrhythmic consequences. The most clinically significant proarrhythmic response to Class IC agents is likely due to an interaction with acute ischemia, and hospitalization for initiation of drug therapy has little predictive or preventive value. Amiodarone has a low risk of proarrhythmia, and any proarrhythmic reactions are generally delayed. Class IA and Class III antiarrhythmic drugs cause acquired long QT syndrome arrhythmias, which can occur soon after initiation of therapy; however, only about half of the arrhythmic events occur within 3 days of initiation of therapy. It could be argued that all patients should be hospitalized to begin Class IA or Class III drugs; however, this approach has a low yield and is extremely expensive. An alternative is to use Class IA and Class III drugs for patients at low risk of torsades de pointes (e.g., males without heart failure, ventricular tachyarrhythmias, or active coronary disease), in whom hospitalization for drug initiation is not warranted. Higher risk patients are probably better treated with other agents, such as Class IC drugs or amiodarone for women without organic heart disease and amiodarone for patients with heart failure, a history of ventricular tachycardia, or active coronary disease. When a Class IA or Class III drug is required for patient with an increased risk of torsades de pointes, hospital admission for drug initiation may be indicated.

Selecting an antiarrhythmic agent for atrial fibrillation should be a patient-specific, data-driven decision

Selecting an antiarrhythmic agent for atrial fibrillation (AF) should be a patient-specific decision. When possible, it should be based on sound rationale and available clinical data. This article details many of the thought processes that must go into this decision process and offers some suggested algorithmic starting points based on these considerations. With a patient's first episode of AF, termination is appropriate, but antiarrhythmic therapy should usually be withheld in order to assess the recurrence pattern. However, if severe hemodynamic or ischemic intolerance would make recurrence a serious risk, or if an early symptomatic recurrence is highly likely, antiarrhythmic therapy would be appropriate. Acute AF may terminate spontaneously or may be terminated iatrogenically. The latter may be achieved by direct current or pharmacologic approaches. The risks, benefits, and optimum utility of these approaches are addressed in the article. Infrequent recurrences may be treated with cardioversion; frequent or severely symptomatic episodes are best treated with attempts at suppression with chronic antiarrhythmic drug administration. Since the therapeutic efficacy of maintaining sinus rhythm is similar for the currently available agents, the drug selection process should be based in large part on safety and convenience considerations. The factors underlying this selection process and one suggested algorithm for drug choice are provided in this article.

Rhythm management in atrial fibrillation--with a primary emphasis on pharmacologic therapy: Part 3

Atrial fibrillation (AF) is the most common, sustained, symptomatic tachyarrhythmia that clinicians are called upon to manage. Management strategies include ventricular rate control coupled with anticoagulation, versus restoration and maintenance of sinus rhythm. Rate control may be achieved pharmacologically, with agents that impair AV nodal conduction directly and/or by increasing parasympathetic/sympathetic balance, or by modifying or ablating the AV nodal region anatomically. Rhythm control may be achieved by electrical or pharmacologic conversion followed by maintenance of sinus rhythm by pharmacologic (or occasionally ablative) therapies. This article will present current approaches to rate and rhythm control issues in atrial fibrillation. Parts 1 and 2, published previously, dealt with rate control and with the restoration of sinus rhythm. Part 3, the current article, details the selection process of choosing a therapy to maintain sinus rhythm, including the likelihood of success, the risks of therapy, and individualization of therapy as dependent upon the nature of the structural heart disease present. It also discusses nonpharmacologic approaches that have been recently developed or are undergoing development. One suggested drug selection algorithm is provided.

Update on Atrial Fibrillation: Restoration of Sinus Rhythm or Ventricular Rate Control?

In patients with persistent atrial fibrillation, two therapeutic alternatives exist, namely restoration and maintenance of sinus rhythm versus ventricular rate control combined with anticoagulation. Currently, the selection of the best therapeutic strategy in an individual patient relies for the most part on clinical judgement and personal experience. At present, there are no prospective scientific data to support the superiority of one treatment over the other with respect to overall survival or quality of life. This review summarizes the present knowledge on this important clinical problem with particular emphasis on issues such as efficacy of antiarrhythmic drugs to prevent recurrent atrial fibrillation, proarrhythmic hazards of these compounds, or efficacy and safety of anticoagulation in nonrheumatic atrial fibrillation. These data serve as the basis of ongoing clinical trials prospectively comparing the merits and demerits of the two therapeutic strategies in the most common arrhythmia encountered in clinical practice.

Treatment strategies for atrial fibrillation

Atrial fibrillation is the most common arrhythmia observed in clinical practice, occurring in 0.4% of the general population and in up to 4% of people greater than 60 years old. It is often associated with other cardiovascular disorders, such as hypertension, coronary artery disease, or cardiomyopathy. Critical evaluation and management of patients with atrial fibrillation requires knowledge of etiology, prognosis, and treatment options of this arrhythmia. On initial presentation, emergency electrical cardioversion should be performed if the patient is hemodynamically unstable. If the patient is stable, initial rate control is recommended, using atrioventricular nodal blocking agents. Further treatment mainly depends upon the duration of the episode. Patients who are in atrial fibrillation <48 hours can be safely cardioverted. Patients who are in atrial fibrillation for >48 hours are commonly anticoagulated for 3 to 4 weeks before and after cardioversion because of the risk of thromboembolism formation in the left atrial appendage. An alternate strategy, which is especially attractive when immediate cardioversion is desired, is transesophageal echocardiography to exclude left atrial thrombus followed by prompt cardioversion. After cardioversion, sinus rhythm can be maintained with class I and III drugs, such as flecainide and propafenone or amiodarone and sotalol. New treatment options, such as atrial defibrillation, atrioventricular junctional ablation, or modification of atrial pacing to prevent atrial fibrillation, are currently under investigation. Although atrial fibrillation is so common in clinical practice, it still remains difficult to treat. Conversion and maintenance to sinus rhythm with antiarrhythmic drug therapy has not shown any improvement in mortality, and some patients may benefit more from ventricular rate control. This review article discusses different treatment strategies for patients with atrial fibrillation.

Cost effectiveness of inpatient initiation of antiarrhythmic therapy for supraventricular tachycardias

This study assessed the cost effectiveness of inpatient antiarrhythmic therapy initiation for supraventricular tachycardias using a metaanalysis of proarrhythmic risk and a decision analysis that compared inpatient to outpatient therapy initiation. A MEDLINE search of trials of antiarrhythmic therapy for supraventricular tachycardias was performed, and episodes of cardiac arrest, sudden or unexplained death, syncope, and sustained or unstable ventricular arrhythmias were recorded. A weighted average event rate, by sample size, was calculated and applied to a clinical decision model of therapy initiation in which patients were either hospitalized for 72 hours or treated as outpatients. Fifty-seven drug trials involving 2,822 patients met study criteria. Based on a 72-hour weighted average event rate of 0.63% (95% confidence interval, 0.2% to 1.2%), inpatient therapy initiation cost $19,231 per year of life saved for a 60-year-old patient with a normal life expectancy. Hospitalization remained cost effective when event rates and life expectancies were varied to model hypothetical clinical scenarios. For example, cost-effectiveness ratios for a 40-year-old without structural heart disease and a 60-year-old with structural heart disease were $37,510 and $33,310, respectively, per year of life saved. Thus, a 72-hour hospitalization for antiarrhythmic therapy initiation is cost effective for most patients with supraventricular tachycardias.

Antiarrhythmic drug therapy in the management of atrial fibrillation

Antiarrhythmic drugs have been used for the acute conversion of atrial fibrillation to sinus rhythm, as well as for the long-term maintenance of sinus rhythm. In recent years, concerns regarding antiarrhythmic drug efficacy as well as safety have prompted a re-examination of the indications for antiarrhythmic therapy in patients with atrial fibrillation. This review will focus on the safety and efficacy of antiarrhythmic therapy in the acute and chronic management of patients with atrial fibrillation.

Factors predisposing to the development of atrial fibrillation

Atrial fibrillation (AF) is in most patients (approximately 70%) associated with organic heart disease including valvular heart disease, coronary artery disease, hypertension, hypertrophic cardiomyopathy, dilated cardiomyopathy, and congenital heart disease, mostly atrial septal defect in adults. In many chronic conditions, determining whether AF is the result or is unrelated to the underlying heart disease, remains unclear. The list of possible etiologies also include cardiac amyloidosis, hemochromatosis and endomyocardial fibrosis. Other heart diseases, such as mitral valve prolapse (without mitral regurgitation), calcifications of the mitral annulus, atrial myxoma, pheochomocytoma, and idiopathic dilated right atrium may present with AF. Atrial fibrillation may occur in the absence of detectable organic heart disease, the so-called "lone AF", in about 30% of cases. The term "idiopathic AF" implies the absence of any detectable etiology including hyperthyroidism, chronic obstructive lung disease, overt sinus node dysfunction, and overt or concealed preexcitation (Wolff-Parkinson-White syndrome), only to mention a few of other uncommon causes of AF. The autonomous nervous system may contribute to the occurrence of AF in some patients. AF occurs commonly. In patients with valvular heart disease, AF is common, particularly when the mitral valve is involved. The occurrence of AF is unrelated to the severity of mitral stenosis or mitral regurgitation but is more common in patients with enlarged left atrium and congestive heart failure. In patients with coronary artery disease, AF occurs predominantly in older patients, males, and patients with left ventricular dysfunction, Important predictive factors of AF include hypertension, left ventricular hypertrophy and diabetes. The risk of the development of AF, in an individual patient, is often difficult to assess. Increasing age, presence of valvular heart disease, and congestive heart failure increase the risk of atrial fibrillation.

Restoring Sinus Rhythm in Patients With Atrial Flutter and Fibrillation: Pharmacologic or Electrical Cardioversion?

Atrial fibrillation and atrial flutter, the most frequently encountered tachyarrhythmias requiring treatment, have become a major focus for clinical and basic research in recent years. Restoration and maintenance of sinus rhythmn, having been shown to improve exercise capacity, alleviate symptoms, and reduce the incidence of thromboembolic events, may be the optimal management strategy. Identification of the safest, most efficacious and cost-effective means of restoring sinus rhythm is necessary prior to the institution of optimal antiarrhythmic therapy to maintain sinus rhythm. Potential advantages of pharmacologic compared with electrical cardioversion include lack of need for general anesthesia and likely lower cost. Pharmacologic conversion include lack of need for general anesthesia and likely lower cost. Pharmacologic conversion has been accomplished with drugs that prolong atrial refractorinerss, including class Ia (quinidine, procainamide, disopyramide), class Ic (flecainide, propafenone), and class II (sotalol, amiodarone) compounds. The so-called pure class III agents were created to overcome the blocker side effects of sotalol and the complex pharmacodynamic profile of amiodarone. Two such agents are dofetilide, which selectively blocks the rapid component of the delayed rectifier current (Ikr) and ibutilide, which augments the slow inward sodium current, with a smaller component of action mediated by the block of Ikr. Reported overall conversion rates for recent onset atrial fibrillation and atrial flutter were 31% and 54% for difetilide, respectively, and 29-31% and 38-63%, respectively, for ibutilide. Proarrhythmia, manifested as polymorphic ventricular tachycardia requiring cardioversion, was a significant early side effect of both agents. Data from clinical trtials with these new agents, combined with increasing nowledge of the electrophysiologic substrate for these arrhythmias, has renewed initerest in the development of safer, more efficacious class IIIdrugs for atrial fibrillation and atrial flutter conversion.

Antiarrhythmic drug therapy in the treatment of atrial fibrillation

Treatment of atrial fibrillation is often unsatisfactory because no available drug has been shown to be clearly superior for maintaining patients in sinus rhythm, and all agents have significant potential for toxicity. Selection of an antiarrhythmic drug is more likely to be based on the drug's potential for toxicity, rather than its demonstrated superior efficacy in the treatment of atrial fibrillation. Careful assessment of each patient for contraindications to individual agents and the likelihood of treatment success needs to be done before initiating antiarrhythmic therapy.

Therapeutic strategies for atrial fibrillation. The value of decision analysis

In the absence of randomized, controlled trials of low-dose amiodarone in atrial fibrillation or a randomized, controlled trial of ventricular rate control versus antifibrillatory therapy, a Markov decision analysis is useful in comparing different therapeutic strategies for atrial fibrillation. The decision analysis described compared warfarin, quinidine, and low-dose amiodarone in patients with asymptomatic or minimally symptomatic chronic, persistent atrial fibrillation. This model suggests that electrical cardioversion followed by low-dose amiodarone is a relatively safe, effective alternative to long-term warfarin therapy.

Atrial fibrillation: maintenance of sinus rhythm versus rate control

Atrial fibrillation represents a common and challenging arrhythmia. A rational approach to management of the individual case depends on careful assessment of the temporal of the arrhythmia, any associated cardiovascular disease, and any particular features suggesting the advisability or risks of any particular treatment regimen. The nature of an arrhythmia and of individual patient factors change over time, requiring a flexible approach to long-term treatment that may be defined only after months or years. While new treatment options such as catheter ablation techniques and implantable atrial defibrillators are being tested, old therapies (e.g., low-dose amiodarone) are undergoing reappraisal. Increasing recognition of the dangers of antiarrhythmic therapy used to maintain sinus rhythm is focusing attention on nonpharmacologic methods. All patients with persistent atrial fibrillation merit serious consideration for direct current cardioversion before accepting that atrial fibrillation is permanent, and many patients may benefit from more than one attempt to restore and maintain sinus rhythm.

Newer developments in the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. Unlike reentrant supraventricular tachycardia and malignant ventricular tachyarrhythmias, for which highly effective and safe nonpharmacologic therapies are available, the treatment of AF remains controversial and often problematic. Whereas electrical cardioversion restores sinus rhythm in most patients with AF, the maintenance of sinus rhythm often requires membrane-active antiarrhythmic drugs that may increase mortality by inducing ventricular proarrhythmia. The control of ventricular response rate, often associated with oral anticoagulation to prevent thromboembolic complications, is an alternative strategy in AF management. The relative efficacy and risks of these strategies and their respective role in different patient subgroups remain to be established. This article focuses on newer developments in the management of AF, including prospects for improved methods to maintain sinus rhythm, newer approaches to rate control, controversies regarding the use of oral anticoagulation, and novel nonpharmacologic therapies. These newer developments may lead over the next 10 years to a revolution in the management of AF as profound as that produced over the last 10 years by nonpharmacologic therapy of other arrhythmias.

Efficacy of type 1C antiarrhythmic agents for treatment of resistant atrial fibrillation

In order to determine the efficacy of type 1C agents (flecainide, encainide, propafenone) in patients with atrial fibrillation who have failed to maintain sinus rhythm with type 1A agents (quinidine, procainamide, disopyramide), 147 patients, that were admitted into the John Dempsey Hospital with new or recurrent atrial fibrillation between 1987-1991, were studied retrospectively. Out of the total, 29 patients converted spontaneously to sinus rhythm, 14 patients were left in atrial fibrillation, and 104 patients were given a type 1A antiarrhythmic. Sixty-five of these patients remained in sinus rhythm (54% converted on drug alone, 46% required electrical cardioversion) for at least 6 months. Of the remaining 39 patients, 28 were given a type 1C antiarrhythmic; 13 were successfully converted (61% chemical, 39% electrical) to and remained in sinus rhythm for at least 6 months; the remaining 15 either failed to convert or reverted to atrial fibrillation. New onset atrial fibrillation had a significantly lower incidence of congestive heart failure (10%) than recurrent atrial fibrillation (33%; P < 0.01). No differences in digoxin, beta blocker use, or other clinical characteristics were seen either between type 1A or type 1C successes or failures. Similarly, echocardiographic dimensions did not predict success or failure with either class of agent. In conclusion, type 1C antiarrhythmics for suppression of recurrent atrial fibrillation represent a reasonable therapeutic alternative for suppression of atrial fibrillation in patients who have failed type 1A agents. Prognostic factors predicting success or failure remain undetermined.

Atrial fibrillation: new management strategies

The main goal of therapy in atrial fibrillation is to restore sinus rhythm, if this is possible, to avoid adverse hemodynamic, electrical, and embolic consequences. The restoration of sinus rhythm is urgent if the patient is unstable. In a stable patient, if the duration is shorter than 48 hours and an atrial thrombus is unlikely, then sinus rhythm can be restored after initial rate control. If the duration of atrial fibrillation is more than 48 hours, the embolic risk may be significant, and anticoagulation will be required for 2 to 4 weeks before an attempt at cardioversion. In patients in whom sinus rhythm cannot be restored or maintained, the goal of therapy is rate control and reduction of embolic risk unless the risk of anticoagulation outweighs its benefit. In difficult cases, rate control may be accomplished with AV nodal ablation and pacemaker implantation or with one of the surgical procedures described above with varying degrees of normalization of the physiology. Although not included in this flow chart, we do not advocate episodic intermittent therapy for patients with infrequent episodes of atrial fibrillation because this could be potentially dangerous and may place the patient at a higher risk for developing proarrhythmia.

Assessment of the efficacy and safety of antiarrhythmic therapy for chronic atrial fibrillation: observations on the role of trial design and implications of drug-related mortality

The findings in clinical trials of antiarrhythmic drug efficacy and safety are frequently difficult to compare, since study design often has an important effect on trial outcome. To explore this problem further, we compared three designs--randomized control, nonrandomized control, and uncontrolled--collectively enrolling 2415 patients in 21 trials reporting on the role of quinidine in the prevention of chronic atrial fibrillation. The proportion of patients remaining in sinus rhythm at 3, 6, and 12 months after cardioversion was calculated by means of Kaplan-Meier techniques, and the data were pooled for each trial design. For the randomized control trials the difference in the absolute percentage of patients remaining in sinus rhythm in the quinidine and control groups was 24% at each of the three follow-up intervals. Contrary to findings in the randomized control trials, the magnitude of the treatment benefit in nonrandomized trials was smaller and declined markedly over time. The percentage of patients remaining in sinus rhythm in the uncontrolled trials was intermediate to the percentages in the other two trial designs. When the data from all three trial designs were pooled, the crude mortality rate was 2.0% in quinidine-treated patients and 0.6% in control patients. Sudden cardiac death or ventricular fibrillation was the cause of death in 13 of 19 patients for whom the cause of death was known, highlighting the potential risk of quinidine-induced proarrhythmia. Although quinidine is effective in maintaining sinus rhythm, estimates of the treatment effect vary among trial types.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of amiodarone versus quinidine and verapamil in patients with chronic atrial fibrillation: results of a comparative study and a 2-year follow-up

Rapid, reliable and safe reestablishment of sinus rhythm is the major aim of pharmacologic treatment in patients with chronic atrial fibrillation. The mainstay of therapy in this arrhythmia has been quinidine. More recently, amiodarone was shown in non-comparative studies to be superior to class IA agents under certain conditions. In 40 patients with atrial fibrillation persisting for 4 weeks up to 2 years, the efficacy and safety of either quinidine and verapamil (days 1 to 3, quinidine 1,500 mg/day; days 4 to 6, quinidine 1,500 mg + verapamil 240 mg/day) or amiodarone therapy (days 1 to 3, amiodarone 1,200 mg/day intravenously; days 4 to 14, amiodarone 800 mg/day orally) were randomly examined. Responders continued on their effective medication for 3 months. Thereafter, all patients were treated with a fixed regimen of quinidine (480 mg/day) plus verapamil (240 mg/day) for up to 2 years. During atrial fibrillation, quinidine reduced mean ventricular cycle length by 40 ms (-5%), quinidine and verapamil increased mean cycle length by 57 ms (8%) and amiodarone by 192 ms (28%, p less than 0.01). In addition, quinidine and verapamil had a characteristic "rate-smoothing" effect on atrioventricular conduction during atrial fibrillation. The rhythm was converted to sinus rhythm after quinidine in 5 (25%) of 20 patients and after the combination of quinidine and verapamil in 11 (55%) of 20 patients. Amiodarone restored sinus rhythm in 12 (60%) of 20 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of disopyramide in conversion and prophylaxis of post-thyrotoxic atrial fibrillation

Rhythm conversion in patients with post-thyrotoxic atrial fibrillation (AF) has been performed with disopyramide in order to evaluate the conversion rate and to test its effect on the maintenance of sinus rhythm after cardioversion. The duration of AF ranged from 9 to 122 months (mean 31.8 months). Of 81 patients, 12 (15%) with relatively short duration AF were converted to sinus rhythm with disopyramide. The remaining 69 patients required DC cardioversion, which restored sinus rhythm in 58 patients. The 58 DC-converted patients were divided into two groups: a disopyramide group (D group) and a non-disopyramide group (non-D group). The D group received disopyramide 300 mg per day for 3 months after DC cardioversion and the non-D group did not receive anti-arrhythmic drugs. During the early observation period, only one patient relapsed in the D group into AF, but 5 successive patients in the non-D group reverted to AF, forcing discontinuation of the non-D protocol. A second DC cardioversion performed on 3 of those 5 patients was followed by maintenance therapy with disopyramide 300 mg per day, and they remained in sinus rhythm. With the inclusion of those three subjects, sinus rhythm was still present in 44 of the total of 58 patients converted by DC (76%) at the time of follow-up (64 months). Thus, disopyramide was effective in rhythm conversion and it was essential for the maintenance of sinus rhythm after cardioversion in patients with post-thyrotoxic AF.

Sotalol versus quinidine for the maintenance of sinus rhythm after direct current conversion of atrial fibrillation

This open, parallel-group study compares quinidine and sotalol treatment for maintenance of sinus rhythm after direct current conversion of patients with chronic atrial fibrillation. The patients from 15 centers in Sweden were randomized to sotalol (98 patients) or quinidine (85 patients) after 2 hours of sinus rhythm after direct current conversion. According to primary efficacy assessment, 52% of the patients in the sotalol group and 48% of the patients in the quinidine group remained in sinus rhythm during the following 6-month treatment period (NS). Furthermore, 34% of the patients treated with sotalol and 22% of the patients treated with quinidine relapsed into atrial fibrillation (NS). Heart rate after relapsing into atrial fibrillation was higher in the patients treated with quinidine (109 beats/min) than in the patients treated with sotalol (78 beats/min, p less than 0.001). Patients treated with sotalol were found to be less symptomatic at the time of relapse compared with relapsing patients in the quinidine group. In terms of safety, more patients were withdrawn from quinidine than from sotalol treatment (26% vs. 11%, p less than 0.05), and sotalol was generally better tolerated than quinidine. Twenty-eight percent of the patients treated with sotalol and 50% of the patients treated with quinidine reported side effects (p less than 0.01). The difference was primarily a result of early (within the first month of treatment) gastrointestinal and skin side effects in the group of patients treated with quinidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy and safety of quinidine therapy for maintenance of sinus rhythm after cardioversion. A meta-analysis of randomized control trials

Because individual studies evaluating the role of quinidine in the maintenance of sinus rhythm after cardioversion from chronic atrial fibrillation have involved relatively few patients, a meta-analysis of randomized control trials was performed. Six trials published between 1970 and 1984 were selected by two blinded reviewers based on study design and statistical analysis. Data from these six trials involving 808 patients were pooled after testing for homogeneity of treatment effects across trials. Life table estimates of the percent of patients still in sinus rhythm at 3, 6, and 12 months after cardioversion were constructed for quinidine and control groups. The proportion of patients remaining in sinus rhythm in the quinidine group was 69%, 58%, and 50% at 3, 6, and 12 months postcardioversion respectively. The proportion of patients remaining in sinus rhythm in the control group was 45%, 33%, and 25% at the same time intervals. The pooled rate difference, or difference in proportion of patients in sinus rhythm between quinidine and control groups, was 24%, 23%, and 24% at 3, 6, and 12 months of follow-up (p less than 0.001 at all time intervals). The unadjusted total mortality rate in the quinidine-treated patients was 2.9% and in the control group was 0.8%. The odds of dying in the quinidine-treated group were approximately three times that of the control group ("typical" odds ratio = 2.98, p less than 0.05). Thus, quinidine treatment is more effective than no antiarrhythmic therapy in suppressing recurrences of atrial fibrillation but appears to be associated with increased total mortality.

Quinidine treatment of chronic lone atrial fibrillation

Patients with chronic lone atrial fibrillation (LAF) were treated with quinidine according to a special schedule to establish sinus rhythm and prevent recurrences. Twenty-seven patients following this schedule were identified retrospectively. To prevent relapses, quinidine had been continued in 25 patients in doses 100 mg quid lower than those used for conversion. In 8 of the latter group, quinidine had to be discontinued or reduced. All patients converted to sinus rhythm. If well tolerated, quinidine prevented recurrence of LAF in 75% of those on long-term (mean follow-up 3.5 years) prophylaxis. After discontinuation of quinidine in 8 patients, LAF recurred in all but one patient. Side effects were observed in 22% of the patients and precluded continuation of the prophylaxis in 15%. No incidence of torsade de pointes was encountered.

Prophylactic treatment after electroconversion of atrial fibrillation

Atrial fibrillation is a common arrhythmia. Sinus rhythm can often be restored by electroconversion, but the relapse rate is high. Various antiarrhythmic drugs have been used to maintain sinus rhythm after electroconversion. This article reviews the experience with these drugs and suggests a treatment strategy.

Efficacy and safety of flecainide acetate in the maintenance of sinus rhythm after electrical cardioversion of chronic atrial fibrillation or atrial flutter

The efficacy and safety of flecainide were studied in the maintenance of sinus rhythm after electrical cardioversion for chronic atrial fibrillation or atrial flutter. Eighty-one patients were randomized to flecainide treatment or no treatment. Baseline characteristics of both groups were comparable. Compared to previous studies, patients could be classified as difficult-to-treat patients. Multiple regression analysis showed New York Heart Association class I for exercise tolerance (p = 0.0004) and flecainide treatment (p = 0.01) to be the main factors increasing the arrhythmia-free episode. However, Mantel-Cox lifetable analysis did not reveal significant differences between arrhythmia-free survival curves of both treatment groups. In the flecainide-treated group, 9% of patients experienced side effects, mostly related to negative dromotropic effects. The incidence of ventricular proarrhythmia in this group of patients was low. Thus, flecainide may be effective in postponing arrhythmia recurrence, even in difficult-to-treat patients. Caution should be excercised in treating patients with underlying conduction disturbances, sick sinus syndrome or characteristics favoring development of ventricular proarrhythmia.

Long-term oral propafenone therapy for suppression of refractory symptomatic atrial fibrillation and atrial flutter

Sixty patients who had recurrent episodes of symptomatic atrial fibrillation or flutter, or both, and who had failed one to five prior drug trials were treated with open label oral propafenone hydrochloride. On a mean maximal tolerated dose of 795 +/- 180 mg/day, actuarial estimates of the percent of individuals free of recurrences of symptomatic atrial fibrillation/flutter during propafenone treatment were: 1 month, 54%; 3 months, 44% and 6 months, 40%. No individual baseline characteristic achieved statistical significance as a correlate of poor response to propafenone. Drug-related adverse reactions were reported in 22% of patients but were severe enough to require termination of propafenone in only 5%. Thus, oral propafenone is a useful and well tolerated drug for long-term suppression of symptomatic recurrences of atrial fibrillation/flutter despite a history of unresponsiveness to prior antiarrhythmic drug treatment.

Comparative efficacy and safety of short-acting and sustained release quinidine in the treatment of patients with ventricular arrhythmias

A comparative, fixed-dose, parallel, randomized, blinded trial to define the efficacy and safety of a new once-a-day quinidine preparation, Quiniday, at 1200 mg per day, was compared to quinidine sulfate (as Quinora, 300 mg four times daily, and Quinidex Extentabs, 600 mg twice daily) and to quinidine gluconate (as Quinaglute Dura-Tabs, 648 mg twice daily). After placebo washout from all prior antiarrhythmic agents, 76 patients with at least 30 ventricular premature complexes (VPCs)/hr on 48-hour ambulatory monitoring were randomized to 3 weeks of treatment with one of the four study drugs. There was no difference in the etiologic, demographic, New York Heart Association therapeutic classification, or ventricular arrhythmia frequency at baseline between the patients randomized to the four groups. There was no statistically significant difference between the percent efficacy for VPC reduction on any drug compared to baseline or in the percent efficacy of reduction in beats of ventricular tachycardia. There was no difference between the four agents in terms of types of side effects noted nor in their overall prevalence or need for premature discontinuation of therapy. This study demonstrated that a variety of quinidine preparations exist that do not differ in terms of their efficacy or safety, but that a long-acting, once-a-day preparation (Quiniday) was as effective and safe as other forms of quinidine despite its once-a-day dosing schedule. More compliant dosing regimens with effective well-known antiarrhythmic agents are important in the treatment of patients with potentially lethal ventricular arrhythmias, in the hope that sudden cardiac death can be prevented.

Use of amiodarone in the treatment of persistent and paroxysmal atrial fibrillation resistant to quinidine therapy

The efficacy of amiodarone was assessed in 38 patients with atrial fibrillation resistant to quinidine and an effort made to identify factors correlated with amiodarone response. The study group included 29 patients with and 9 without organic heart disease and either persistent (n = 11) or paroxysmal (n = 27) atrial fibrillation. All patients were treated with amiodarone and followed up in a research clinic. Efficacy was classified as excellent (no recurrent symptomatic atrial fibrillation) in 15 (55%) of 27 patients with paroxysmal and 5 (45%) of 11 patients with persistent atrial fibrillation. Efficacy was poor (no effect on atrial fibrillation) in 5 (19%) of 27 patients with paroxysmal and 6 (55%) of 11 patients with persistent atrial fibrillation. Efficacy was good (amelioration but not total suppression) in 7 (26%) of 27 patients with paroxysmal atrial fibrillation. Efficacy was related to echocardiographic left atrial dimension, left ventricular ejection fraction and, in patients with persistent atrial fibrillation, the duration of the arrhythmia. During the follow-up period of 15 months (range 1 to 36), overall efficacy (considering response and toxicity) was 67% in the 27 patients with paroxysmal and 45% in the 11 patients with persistent atrial fibrillation. It is concluded that amiodarone offers an additional therapeutic alternative in quinidine-resistant atrial fibrillation and that certain clinical factors are correlated with amiodarone response.

Comparison of two long-acting forms of quinidine

The bioequivalence of two forms of long acting quinidine compounds was assessed (Kinidin durules and Longacor) using drug plasma level and QT ECG changes. Six healthy volunteers received each preparation on two occasions in random order. The wash out period between successive experiments was at least 7 days. There was no difference in tmax, Cmax and AUC for plasma level and adjusted QT. However, between patient variability was large. A 20% difference in plasma levels could not be excluded but the difference in QT max and QT AUC between the two preparations did not exceed 20% (P less than 0.05, Westlake's method). This study illustrates the fact that pharmacodynamic equivalence, let alone therapeutic equivalence, does not necessarily imply plasma level equivalence, as assessed by the current method.