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

Machine Learning Prediction for the Recurrence After Electrical Cardioversion of Patients With Persistent Atrial Fibrillation

BACKGROUND AND OBJECTIVES

There is limited evidence regarding machine-learning prediction for the recurrence of atrial fibrillation (AF) after electrical cardioversion (ECV). This study aimed to predict the recurrence of AF after ECV using machine learning of clinical features and electrocardiograms (ECGs) in persistent AF patients.

METHODS

We analyzed patients who underwent successful ECV for persistent AF. Machine learning was designed to predict patients with 1-month recurrence. Individual 12-lead ECGs were collected before and after ECV. Various clinical features were collected and trained the extreme gradient boost (XGBoost)-based model. Ten-fold cross-validation was used to evaluate the performance of the model. The performance was compared to the C-statistics of the selected clinical features.

RESULTS

Among 718 patients (mean age 63.5±9.3 years, men 78.8%), AF recurred in 435 (60.6%) patients after 1 month. With the XGBoost-based model, the areas under the receiver operating characteristic curves (AUROCs) were 0.57, 0.60, and 0.63 if the model was trained by clinical features, ECGs, and both (the final model), respectively. For the final model, the sensitivity, specificity, and F1-score were 84.7%, 28.2%, and 0.73, respectively. Although the AF duration showed the best predictive performance (AUROC, 0.58) among the clinical features, it was significantly lower than that of the final machine-learning model (p<0.001). Additional training of extended monitoring data of 15-minute single-lead ECG and photoplethysmography in available patients (n=261) did not significantly improve the model's performance.

CONCLUSIONS

Machine learning showed modest performance in predicting AF recurrence after ECV in persistent AF patients, warranting further validation studies.

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.

Atrial fibrillation management in a breeding stallion

A 20-year-old warmblood breeding stallion presented to a University practice for semen collection and evaluation was incidentally diagnosed with atrial fibrillation (AF). Electrocardiogram recordings during breeding revealed inappropriately rapid tachycardia and occasional ventricular premature depolarizations/aberrant ventricular conduction. Transvenous electrical cardioversion was performed. After successful cardioversion the horse displayed supraventricular ectopy and atrial contractile dysfunction and was administered sotalol hydrochloride in an attempt to decrease the risk of AF recurrence. Supraventricular ectopy and echocardiographic evidence of atrial dysfunction gradually improved and normalized over 6 months. No direct adverse effects of the chronic anti-arrhythmic treatment were observed and libido and semen quality were unaffected. AF recurred 6 months after cardioversion and sotalol therapy was continued to control the ventricular ectopy/aberrant ventricular conduction during semen collection. Considerations regarding pathologic arrhythmias and inappropriately high heart rates in breeding stallions with AF may be similar to those in riding horses. Sotalol hydrochloride was a safe anti-arrhythmic drug in the management of this case.

The Past, Present, and Potential Future of Sodium Channel Block as an Atrial Fibrillation Suppressing Strategy

Despite major advances in arrhythmia therapy, atrial fibrillation (AF) remains a challenge. A significant limitation in AF management is the lack of safe and effective drugs to restore and/or maintain sinus rhythm. The rational design of a new generation of AF-selective Na(+) channel blockers (NCBs) is emerging as a promising AF-suppressing strategy. Recent theoretical and experimental advances have generated insights into the mechanisms underlying AF maintenance and termination by antiarrhythmic drugs. Our understanding of antiarrhythmic drug-induced proarrhythmia has also grown in sophistication. These discoveries have created new possibilities in therapeutic targeting and renewed interest in improved NCB antiarrhythmic drugs. Recently described differences in atrial versus ventricular electrophysiology can be exploited in the prospective design of atrial-selective NCBs. Furthermore, state-dependent block has been shown to be an important modulator of NCB rate selectivity. Together, differential atrial-ventricular electrophysiological actions and state-dependent block form the backbone for the rational design of an AF-selective NCB. Synergistic combinations incorporating both NCB and block of K(+) currents may allow for further enhancement of AF selectivity. Future work on translating these basic research advances into the development of an optimized AF-selective NCB has the potential to provide safer and more effective pharmacotherapeutic options for AF, thereby fulfilling a major unmet clinical need.

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.

The efficacy and tolerability of commonly used agents to prevent recurrence of atrial fibrillation after successful cardioversion

A number of therapeutic strategies exist for the restoration and maintenance of sinus rhythm in patients presenting with atrial fibrillation. The acute success rate with electrical cardioversion is high. However, many patients relapse into atrial fibrillation. A major challenge faced by those who care for patients with atrial fibrillation is the long-term maintenance of sinus rhythm whilst avoiding treatment-related adverse effects. This review examines the efficacy and tolerability of conventional anti-arrhythmic drugs for the secondary prevention of atrial fibrillation in the post-cardioversion period.

Success of electrocardioversion on the elderly

BACKGROUND

There are two treatment strategies for medication-resistant atrial fibrillation (AF): rhythm control or rate control. It has been suggested that rate control is a valid strategy in well-tolerated AF because it does not result in increased mortality. We aimed to investigate the 1-year outcome of rhythm control in an elderly population of AF patients.

METHOD

The study was retrospective, using the data collected from electrocardioversions (ECV) of elderly patients and the data of their follow-up visits to the outpatient clinic. We looked for recurrence of AF within the first year after ECV. Furthermore, we investigated possible predictors of recurrence.

RESULTS

From February 2008 till November 2011, 436 consecutive elderly patients admitted for ECV were included. The 1-year recurrence rate of AF was 51.3 %. We found that being female and a large left atrial diameter were independent predictors of recurrence.

CONCLUSION

The AF recurrence rate in our elderly population is comparable with reported AF recurrence rates in a younger population; we conclude that rhythm control can be regarded as the viable strategy in persistent AF in elderly patients.

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.

The safety of flecainide treatment of atrial fibrillation: long-term incidence of sudden cardiac death and proarrhythmic events

OBJECTIVE

To assess the safety of long-term treatment with flecainide in patients with atrial fibrillation (AF), particularly with regard to sudden cardiac death (SCD) and proarrhythmic events.

DESIGN

Retrospective, observational cohort study.

SETTING

Single-centre study at Örebro University Hospital, Sweden. Subjects.  A total of 112 patients with paroxysmal (51%) or persistent (49%) AF (mean age 60 ± 11 years) were included after identifying all patients with AF who initiated oral flecainide treatment (mean dose 203 ± 43 mg per day) between 1998 and 2006. Standard exclusion/inclusion criteria for flecainide were used, and flecainide treatment was usually combined with an atrioventricular-blocking agent (89%).

MAIN OUTCOME MEASURE

Death was classified as sudden or nonsudden according to standard definitions. Proarrhythmia was defined as cardiac syncope or life-threatening arrhythmia.

RESULTS

Eight deaths were reported during a mean follow-up of 3.4 ± 2.4 years. Compared to the general population, the standardized mortality ratios were 1.57 (95% confidence interval (CI) 0.68-3.09) for all-cause mortality and 4.16 (95% CI 1.53-9.06) for death from cardiovascular disease. Three deaths were classified as SCDs. Proarrhythmic events occurred in six patients (two each with wide QRS tachycardia, 1 : 1 conducted atrial flutter and syncope during exercise).

CONCLUSION

We found an increased incidence of SCD or proarrhythmic events in this real-world study of flecainide used for the treatment of AF. The findings suggest that further investigation into the safety of flecainide for the treatment of patients with AF is warranted.

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.

Atrial Fibrillation: The New Epidemic of the Ageing World

The prevalence of atrial fibrillation (AF) increases with age. As the population ages, the burden of AF increases. AF is associated with an increased incidence of mortality, stroke, and coronary events compared to sinus rhythm. AF with a rapid ventricular rate may cause a tachycardia-related cardiomyopathy. Immediate direct-current (DC) cardioversion should be performed in patients with AF and acute myocardial infarction, chest pain due to myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous beta blockers, diltiazem, or verapamil may be administered to reduce immediately a very rapid ventricular rate in AF. An oral beta blocker, verapamil, or diltiazem should be used in persons with AF if a fast ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected patients with symptomatic life-threatening AF refractory to other drugs. Digoxin should not be used to treat patients with paroxysmal AF. Nondrug therapies should be performed in patients with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drugs. Paroxysmal AF associated with the tachycardia-bradycardia syndrome should be treated with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in patients with AF and symptoms such as dizziness or syncope associated with ventricular pauses greater than 3 seconds which are not drug-induced. Elective DC cardioversion has a higher success rate and a lower incidence of cardiac adverse effects than does medical cardioversion in converting AF to sinus rhythm. Unless transesophageal echocardiography has shown no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective DC or drug cardioversion of AF and continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer, especially in elderly patients , ventricular rate control plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs. Patients with chronic or paroxysmal AF at high risk for stroke should be treated with long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Patients with AF at low risk for stroke or with contraindications to warfarin should be treated with aspirin 325 mg daily.

Quinidine revisited

One of the earliest antiarrhythmic drugs developed, quinidine had a significant role in the treatment of many arrhythmias. After concerns for increased risk of ventricular arrhythmia and death with quinidine emerged, the use of quinidine fell dramatically in favor of newer antiarrhythmic medications. However, recent trials have generated renewed interest in the use of quinidine. In particular, quinidine appears to be safe and efficacious in combination with verapamil for the treatment of atrial fibrillation. Quinidine has also been used successfully to treat idiopathic ventricular fibrillation, Brugada syndrome, and Short QT syndrome. Although it is one of the oldest drugs in our armamentarium, quinidine continues to have a role in modern cardiology.

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.

Rate of conversion and recurrence after sotalol treatment in patients with direct current-refractory atrial fibrillation

BACKGROUND

A number of patients with persistent atrial fibrillation (AF) will not have sinus rhythm (SR) restored by direct current (DC) cardioversion.

HYPOTHESIS

In patients with DC-refractory AF, oral pretreatment with sotalol increases the success rate at DC cardioversion.

METHODS

Consecutive patients with persistent AF, refractory at a first DC cardioversion, were prospectively included. A comparative group of patients with AF not refractory at DC cardioversion was studied. Oral sotalol treatment was started after unsuccessful DC cardioversion and given at least 7 days before renewed cardioversion. Four weeks after cardioversion, an electrocardiogram was performed.

RESULTS

In all, 53 patients were enrolled in the study. Forty-three (81%) in the sotalol group regained sinus rhythm (SR): 10 (19%) of these converted pharmacologically and 33 (62%) after a second DC cardioversion; SR was never restored in 10 patients (19%). After 4 weeks, SR was maintained in 29 patients (67%). The comparative group included 132 patients and differed significantly from the DC-refractory patients only with regard to weight. After 4 weeks, SR was maintained by 50 patients (37%) in this group.

CONCLUSIONS

In patients with persistent AF refractory to DC cardioversion, oral pretreatment with sotalol results in a high rate of SR restoration, either pharmacologically or by DC cardioversion. Maintenance of SR at 4 weeks is of sufficient clinical relevance to consider this treatment option in patients with AF refractory to DC cardioversion.

New concepts for old drugs to maintain sinus rhythm in patients with atrial fibrillation

Atrial fibrillation (AF) is a chronic, often progressive disease. Despite the ongoing concerted effort to improve AF therapy, often there is no remedy for curing AF and preventing the deleterious effects of the arrhythmia on health. Antiarrhythmic drug therapy is likely to remain the mainstay of therapy for many patients in the foreseeable future. Available antiarrhythmic drugs are moderately effective, which is important for patients who respond, especially given the chronic and often progressive nature of the disease. This article describes emerging concepts under clinical evaluation that attempt to improve the safety of available antiarrhythmic drugs in the treatment of recurrent AF. Two concepts are reviewed: (1) combination of an antiarrhythmic drug with a calcium channel blocker to reduce proarrhythmic side effects, and (2) "intelligent" reduction of the duration of antiarrhythmic drug therapy targeted to periods of symptomatic or likely AF recurrence.

Self-limited bursts of atrial fibrillation following successful cardioversion

BACKGROUND

To evaluate if self-limited episodes of atrial fibrillation after DC cardioversion predict recurrence of persistent atrial fibrillation. To evaluate the incidence and duration of such episodes as well as their change over time.

METHODS

Consecutive patients with persistent atrial fibrillation, scheduled for direct current cardioversion were prospectively included in the study. Ambulatory ECG Holter monitoring (24 h) was performed one, three and 6 weeks after successful cardioversion.

RESULTS

A total of 84 patients were prospectively included in the study. Sinus rhythm was restored in 74 patients (88%). At 6 weeks of follow-up 40 patients out of 74 (54%) had sinus rhythm, and 34 patients (46%) had relapsed into persistent atrial fibrillation. Eight out of these 34 patients (24%) had bursts of atrial fibrillation at their first Holter recording, compared to 12 patients out of 40 (30%) in sinus rhythm at 6 weeks (p>0.05). On the first, second and third Holter recording 21 patients out of 51 (41%), 21 patients out of 43 (49%) and 15 out of 40 patients (38%) had self-limited bursts of atrial fibrillation, respectively. The incidence or duration of episodes did not vary over time during the 6 weeks of follow-up.

CONCLUSION

In patients successfully converted to sinus rhythm self-limited bursts of atrial fibrillation do not predict recurrence of persistent atrial fibrillation during 6 weeks of follow up. Brief self-limited episodes of atrial fibrillation are common, and the incidence and duration of such episodes are constant during a 6 weeks period after DC cardioversion.

Pharmacotherapy changes following pacemaker implantation in patients with bradycardia-tachycardia syndrome

The management of bradycardia-tachycardia syndrome (BTS) includes bradycardia and tachyarrhythmia therapy. At present, the treatment for symptomatic bradycardia in BTS patients is permanent cardiac pacing. The pharmacological treatment of atrial tachyarrhythmias comprises of rhythm and rate control, and prevention of thromboembolism. Patients with BTS often require both pacemaker and drug therapy. This article reviews the interactions of pacing and drug therapies in BTS. Drugs that alter cardiac electrophysiological properties may influence pacemaker indications, pacing mode selection, efficacy of pacing algorithms and pacing performance. Pacing by preventing drug-induced bradycardia increases the safety of pharmacotherapy and, thus, allows the intensification of those treatments. Pacing therapy and antiarrhythmic drugs used together as a hybrid therapy have a synergistic effect in the prevention of atrial tachyarrhythmias. Atrial-based pacing may reduce atrial tachyarrhythmia burden, allowing reduction of rhythm and rate control. Contemporary pacemakers' memory functions may help guide rhythm and rate control, as well as anticoagulation pharmacotherapy.

Long-term outcome after cardioversion of atrial fibrillation: Prediction of recurrence with P wave signal averaged ECG and chemoreflexsensitivity

AIM

The recurrence of atrial fibrillation after cardioversion was a general problem in medical practice.

METHODS

We wanted to test the hypothesis that the recurrence of atrial fibrillation could be predicted by measurements of P wave triggered P wave signal averaged ECG and chemoreflexsensitivity (CHRS) in 118 consecutive patients one day after successful electrical cardioversion. We measured the filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20) with P wave triggered P wave signal averaged ECG. The CHRS was calculated of a ratio between the difference of RR intervals in ECG and venous pO2 before and after 5-min oxygen inhalation. The pathologic CHRS was predefined as a CHRS below 3.0 ms/mm Hg.

RESULTS

A recurrence of atrial fibrillation was observed in 57 patients (48%) during a 9.3-month follow-up. The left atrial size (41.9+/-4.0 vs. 39.3+/-3.1 mm, P<0.0003) was larger, the FPD (139.6+/-16.0 vs. 118.2+/-14.1 ms, P<0.0001) was longer, the RMS 20 (2.57+/-0.77 vs. 3.90+/-0.99 muV, P<0.0001) and the CHRS (2.66+/-1.18 vs. 4.01+/-1.66 ms/mm Hg, P<0.0001) were lower in patients with recurrence of atrial fibrillation. A cut-off point was defined with FPD > or =126 ms and RMS 20 < or =3.1 muV and could predict atrial fibrillation with a specificity of 77%, a sensitivity of 72%, a positive value of 75%, a negative predictive value of 75% and an accuracy of 75%. Patients with FPD > or =126 ms and RMS 20 < or =3.1 muV had nearly a 7-fold increase risk for recurrence of atrial fibrillation.

CONCLUSION

The recurrence of atrial fibrillation after cardioversion could be detected by P wave signal averaged ECG and an analysis of CHRS. These methods seem to be appropriate to show a delayed atrial conduction and a neurovegetative imbalance which might be possible trigger mechanisms of reinitiating of atrial fibrillation.

[Modern pharmacotherapy of supraventricular and ventricular cardiac arrhythmia. An update for conventional therapy]

Currently the pharmacological approach still represents the mainstay in the acute phase of arrhythmia management as well as in the chronic treatment phase of specific entities such as atrial fibrillation. However, non-pharmacological options have recently emerged as frequently used first-line tools for the treatment of various supraventricular and ventricular heart rhythm disturbances. Nevertheless, antiarrhythmic drug treatment is frequently used as a bridging or adjunctive therapy in conjunction with catheter ablation or implantable cardioverter defibrillators. Antiarrhythmic agents constitute a very heterogeneous group prone to various drug interactions and side-effects. Therefore, this article aims to summarise the most important facts and recent findings with regard to appropriate contemporary pharmacological therapy of atrial and ventricular arrhythmias in clinical practice.

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prediction of the recurrence of atrial fibrillation after successful cardioversion with P wave signal-averaged ECG

BACKGROUND

The recurrence of atrial fibrillation (AF) was often observed after cardioversion.

METHODS

In our study, a P wave triggered P wave signal-averaged ECG (P-SAECG) was performed on 118 consecutive patients 1 day after successful electrical cardioversion in order to evaluate the utility of this method to predict AF after cardioversion. We measured the filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20).

RESULTS

During a 1-year follow-up, a recurrence was observed in 57 patients (48%). Patients with recurrence of AF had a larger left atrial size (41.9 +/- 4.0 vs 39.3 +/- 3.1 mm, P < 0.0003), a longer FPD (139.6 +/- 16.0 vs 118.2 +/- 14.1 ms, P < 0.0001), and a lower RMS 20 (2.57 +/- 0.77 vs 3.90 +/- 0.99 microV, P < 0.0001). A cutoff point (COP) of FPD > or =126 ms and RMS 20 < or =3.1 microV could predict AF with a specificity of 77%, a sensitivity of 72%, a positive value of 75%, a negative predictive value of 75%, and an accuracy of 75%. A stepwise logistic regression analysis of variables identified COP (odds ratio 9.97; 95% CI, 4.10-24.24, P < 0.0001) as an independent predictor for recurrence.

CONCLUSIONS

We conclude that the probability of recurrence of AF after cardioversion could be predicted by P-SAECG. This method seems to be appropriate to demonstrate a delayed atrial conduction that might be a possible risk factor of reinitiation of AF.

Selection of drugs in pursuit of rate control strategy

Atrial fibrillation is the most common sustained arrhythmia. Based on multiple large randomized trials, rate control therapy has been shown to be safe and effective and is gaining greater acceptance as a frontline alternative to drugs to maintain sinus rhythm. Adequate rate control can be achieved by atrioventricular nodal blocking agents both in the acute and chronic settings. In refractory patients, other methods such as atrioventricular node ablation can be used to control rate.

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.

Tedisamil: a new novel antiarrhythmic

Solvay Pharmaceuticals is currently developing tedisamil (KC-8857), a novel antiarrhythmic with additional anti-ischaemic properties, which acts via potassium channel blockade. This drug can be categorised as a class III antiarrhythmic agent due to its effects of action potential and QT interval prolongation in these patients. This agent was initially developed for its anti-ischaemic properties and Phase I trials have shown tedisamil to be an effective bradycardic agent, as well as causing a reverse rate-dependent QT interval prolongation. Subsequent Phase II results have confirmed that in patients with ischaemic heart disease, tedisamil had beneficial haemodynamic and anti-ischaemic effects. Phase III studies in patients with ischaemic heart disease indicated that tedisamil is an effective agent for the treatment of angina, resulting in a dose-dependent increase in anginal threshold (with a decrease in anginal attacks, increased exercise capacity during treadmill exercise and decreased electrocardiographic signs of exercise induced ischaemia) in comparison to placebo. Although tedisamil has been shown to be an effective anti-ischaemic agent, with Phase III trials for angina pectoris now completed, the company are now pursuing the use of tedisamil for the treatment of atrial fibrillation, for which tedisamil is still in Phase II/III clinical trials. Launch data are not yet known.

A benefit–risk assessment of class III antiarrhythmic agents

The prevalence of arrhythmia in the population is increasing as more people survive for longer with cardiovascular disease. It was once thought that antiarrhythmic therapy could save life, however, it is now evident that antiarrhythmic therapy should be administrated with the purpose of symptomatic relief. Since many patients experience a decrease in physical performance as well as a diminished quality of life during arrhythmia there is still a need for antiarrhythmic drug therapy. The development of new antiarrhythmic agents has changed the focus from class I to class III agents since it became evident that with class I drug therapy the prevalence of mortality is considerably higher. This review focuses on the benefits and risks of known and newer class III antiarrhythmic agents. The benefits discussed include the ability to maintain sinus rhythm in persistent atrial fibrillation patients, and reducing the need for implantable cardioverter defibrillator shock/antitachycardia therapy, since no class III antiarrhythmic agents have proven survival benefit. The risks discussed mainly focus on pro-arrhythmia as torsade de pointes ventricular tachycardia.

Simplified cardioversion service with intravenous midazolam

OBJECTIVE

To assess the results of a new cardioversion service that used intravenous midazolam sedation with cardioversion performed with a biphasic defibrillator by an experienced doctor with a prior review of patients in a pre-cardioversion clinic.

METHODS

368 consecutive patients who were treated under the new service over its first 12 months (group 1) were compared with 210 consecutive patients who attended under the old system during the preceding 12 months (group 2). Patients of group 2 had cardioversion under general anaesthesia by junior doctors with a monophasic defibrillator.

RESULTS

There were no anaesthetic or respiratory complications in group 1. Of the patients in group 1, 10.3% remembered the shocks, with only 3.5% considering them unpleasant. Cardioversion was successful in 94.6% of group 1 patients after a mean energy of 117 J compared with 81.4% (p < 0.0001) and a mean energy of 242 J (p < 0.0001) for group 2 patients. Cancellations on the day of the procedure were reduced from 24% in group 2 to 3.4% in group 1.

CONCLUSIONS

The new service was found to be safe and more efficient. It has led to a large reduction in the waiting time for cardioversion.

Recurrence of Atrial Fibrillation After Internal Cardioversion of Persistent Atrial Fibrillation Prognostic Importance of Electrophysiologic Parameters

BACKGROUND

The purpose of this study was to determine whether the extent of atrial electrical remodeling affects the recurrence of atrial fibrillation (AF) after cardioversion of persistent AF (PAF).

METHODS AND RESULTS

Internal atrial cardioversion was performed in 47 patients with PAF. The right atrial monophasic action potential duration (RA-MAPD) at pacing cycle lengths (PCLs) of 800-300 ms and P wave signal-averaged electrocardiogram were recorded after cardioversion. Bepridil (150-200 mg/day) and carvedilol (10 mg/day) were administered to all patients after cardioversion. Of the 47 patients, 20 had recurrent AF within 3 months. No relation was observed between age, left atrial dimension, left ventricular ejection fraction, and AF recurrence. The AF duration was significantly longer (p<0.05) and RA-MAPD at PCLs of 800 to 300 ms were significantly shorter (p<0.05) in patients with AF recurrence than in those without recurrence. The mean slope of the RA-MAPD for PCLs between 600 and 300 ms did not differ between the patients with and without AF recurrence. The filtered P-wave duration (FPD) was significantly longer in the patients with AF recurrence than in those without (p<0.05). Multivariate analysis also showed that the RA-MAPD at a PCL of 300 ms and FPD were predictors of AF recurrence (RAMAPD: p=0.038; FPD: p=0.052).

CONCLUSION

These results suggest that electrical remodeling related to the repolarization and depolarization may be the main contributors to early AF recurrence after cardioversion under the administration of bepridil and carvedilol.

Sotalol versus propafenone for long-term maintenance of normal sinus rhythm in patients with recurrent symptomatic atrial fibrillation

This prospective, randomized, single-blinded, placebo-controlled study compared the efficacy and safety of sotalol and propafenone when used for long-term prevention of atrial fibrillation. For the long-term maintenance of normal sinus rhythm, propafenone seems to be more effective than sotalol.

Use of beta-blockers in atrial fibrillation

Atrial fibrillation is the most common arrhythmia in the general population and is frequently associated with organic heart disease. beta-adrenoceptor antagonists (b-blockers) are very effective in preventing atrial fibrillation after coronary artery bypass surgery. It has been shown recently that the beta-blocker metoprolol controlled release/extended release (CR/XL) is also effective in maintaining sinus rhythm after conversion of atrial fibrillation. There is concern that class I antiarrhythmic drugs, such as quinidine, disopyramide, and flecainide in particular, may increase mortality. The risk of proarrhythmia associated with beta-blocker treatment is very low. Therefore b-blockers, such as metoprolol CR/XL, may be the first line of treatment to maintain sinus rhythm, especially after myocardial infarction and in patients with chronic heart failure and in those with arterial hypertension. In patients with persistent atrial fibrillation, AV-nodal conduction-slowing drugs, such as calcium channel antagonists and beta-blockers are used to control the ventricular rate during atrial fibrillation. Several studies clearly show that beta-blockers alone, or in combination with digoxin are very effective in controlling the ventricular rate at rest and during exercise. beta-blockers are effective in maintaining sinus rhythm and controlling the ventricular rate during atrial fibrillation. Given these effects and their favorable effects on mortality, beta-blockers should be considered as first-line agents in the management of patients with atrial fibrillation.

Implications for Nursing Care of Patients With Atrial Fibrillation

Atrial fibrillation is the most common sustained cardiac dysrhythmia treated in North America and Europe. As such, it is one of the current epidemics in cardiovascular disease. Findings from the AFFIRM (Atrial Fibrillation Follow-up: Investigation of Rhythm Management) and RACE (RAte Control versus Electrical cardioversion for persistent atrial fibrillation) clinical trials are presented and the current evidence for the management of atrial fibrillation using anticoagulation, rate-control, and rhythm-control strategies is outlined. Implications for nurses are discussed including physiologic and psychosocial interventions.

Antiarrhythmic drug therapy of atrial fibrillation

In the post-AFFIRM era, treatment of AF has become the treatment of symptoms. In some patients, this will be simple rate control, but there remain a significant cohort of patients in whom rate control alone does not give acceptable symptom relief. In this group, antiarrhythmic therapy still has a role, and the AFFIRM trial indicates that this therapeutic strategy is without significant deleterious effect on mortality. The choice of antiarrhythmic agent must be individualized according to underlying cardiac pathologies and comorbidities, however. Most recently, the introduction of dofetilide has widened the therapeutic options in patients with severe heart disease, and the Canadian Trial of Atrial Fibrillation indicated the superior efficacy of amiodarone at low doses. The release/ development of newer Class III antiarrhythmic agents may offer hope for the benefits of amiodarone without the serious adverse effects with long-term therapy.

Long-term Maintenance of Normal Sinus Rhythm in Patients With Current Symptomatic Atrial Fibrillation

STUDY OBJECTIVES

To compare the efficacy and safety of amiodarone and propafenone when used for the prevention of atrial fibrillation (AF) and maintenance of normal sinus rhythm in patients with refractory AF.

DESIGN

Prospective, randomized, single-blind trial.

SETTING

Tertiary cardiac referral center.

PATIENTS

One hundred forty-six consecutive patients (72 men; mean age, 63 +/- 10 years [+/- SD]) with recurrent symptomatic AF.

INTERVENTIONS

We studied 146 patients after restoration of sinus rhythm; patients were randomized to amiodarone, 200 mg/d, or propafenone, 450 mg/d. Follow-up clinical evaluations were conducted at the first, second, fourth, and sixth months, and at 3-month intervals thereafter. The proportion of patients relapsing to AF and/or experiencing side effects was calculated for each group using the Kaplan-Meier method. End point of the study was recurrence of AF or occurrence of side effects necessitating discontinuation of medication.

MEASUREMENTS AND RESULTS

Of 146 patients, 72 received amiodarone and 74 received propafenone. The two groups were clinically similar. Of the 72 patients receiving amiodarone, AF developed in 25 patients, after an average of 9.8 months, compared to 33 of the 74 patients receiving propafenone after an average of 3.8 months. Twelve patients receiving amiodarone and 2 patients receiving propafenone had side effects necessitating withdrawal of medication while still in sinus rhythm.

CONCLUSIONS

Amiodarone tends to be more effective than propafenone in maintaining sinus rhythm in patients with AF, but this advantage is offset by a higher incidence of side effects.

A review of clinical trials assessing the efficacy and safety of newer antiarrhythmic drugs in atrial fibrillation

Clinical trials assessing the efficacy of anti- arrhythmic drugs for terminating atrial fibrillation have demonstrated that rate control drugs have little to no added efficacy compared to placebo; however, spontaneous conversion of recent-onset atrial fibrillation is common. Antiarrhythmic drugs such as oral dofetilide, oral bolus-flecainide and propafenone and intravenous ibutilide all have a role in terminating atrial fibrillation. Active comparator trials have demonstrated that amiodarone is more efficacious in maintaining sinus rhythm than propafenone and sotalol. Multiple trials have demonstrated the safety of amiodarone, sotalol, dofetilide and azimilide in a post-myocardial infarction population and amiodarone and dofetilide in a congestive heart failure population. Newer antiarrhythmic agents, some with novel mechanisms of action, will add to the pharmacologic armamentarium in treating atrial fibrillation.

Comparison of recurrence rates after direct-current cardioversion for new-onset atrial fibrillation in patients receiving versus those not receiving rhythm-control drug therapy

The AFFIRM investigators have recommended rate control as the preferred strategy for recurrent atrial fibrillation (AF), but the appropriate strategy for new-onset persistent AF is uncertain. Our study evaluated the AF recurrence rate and the impact of rhythm-control drugs (class 1A, 1C, and 3 antiarrhythmic drugs) on patients with new-onset persistent AF after successful direct-current (DC) cardioversion. Consecutive patients who underwent DC cardioversion of AF from January 1, 1996 to December 31, 1999 were screened for new-onset persistent AF, and 150 patients met the inclusion criteria. After the first DC cardioversion, 50 patients received rhythm-control drugs (rhythm-control group) and the other 100 did not (rate-control group). The 2 groups had similar clinical characteristics except for a lower ejection fraction (44 +/- 14% vs 49 +/- 14%, p <0.01) and a higher proportion of idiopathic dilated cardiomyopathy (20% vs 1%, p = 0.03) in the rhythm-control group versus the rate-control group. During the follow-up period there was a trend toward a lower rate of early AF recurrence at 24 hours after DC cardioversion in the rhythm-control group versus the rate-control group (6% vs 16%, p = 0.11), but there was a high recurrence rate of AF in both groups at 1 month (30% for the rhythm-control group vs 41% for the rate-control group, p = 0.25). At the end of the follow-up period, rhythm-control therapy was abandoned in 78% of the rhythm-control group patients after the failure of 1 to 3 rhythm-control drugs. In the rate-control group, rhythm-control therapy was attempted after AF recurrence in 62 patients but was later abandoned in 48 patients (77%) because of treatment failure. Therefore, the high incidence of treatment failure with rhythm-control therapy suggests that rate control with anticoagulation should be preferred in patients with new-onset persistent AF if AF recurs after DC cardioversion.

Atrial Fibrillation in Heart Failure:

AF in Heart Failure. Atrial fibrillation and congestive heart failure are commonly occurring cardiac disorders that often exist concomitantly. The prognostic significance of the presence or absence of atrial fibrillation, as an independent risk factor, in patients with heart failure remains controversial. Antiarrhythmic drugs with good hemodynamic profiles and neutral effects on survival are preferred treatments for converting atrial fibrillation and maintaining sinus rhythm. Other standard therapies for congestive heart failure, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and beta-blockers also have a role in the treatment of these coexisting disease states. The article presents an overview of atrial fibrillation in patients with heart failure and reviews the prevalence, prognostic significance, and efficacy of various antiarrhythmic agents for the conversion and maintenance of sinus rhythm.

Review of the current management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Its prevalence is increasing and accordingly, so is its burden on healthcare systems throughout the world. The pathophysiology of AF is complex and poorly understood, which of itself presents a major challenge to the management of this important condition. AF is associated with increased morbidity and mortality, particularly in patients with underlying left ventricular dysfunction. Once AF occurs, it is often difficult to 'cure' and as such, the major focus of therapy is currently divided essentially between a rate control strategy and a need to revert to and maintain sinus rhythm. Both approaches seek to minimise the associated symptoms and complications. Over the past two decades, numerous pharmacological approaches to the management of AF have been employed, many of which have been shown to be relatively ineffective or confounded by major complications. Accordingly, recent research and interest has focused on non-pharmacological electrophysiological therapies to either cure AF or improve symptoms. This review summarises the current approaches to the management AF and provides some new insights into emerging therapies for this common clinical problem.