Ventricular rate control in chronic atrial fibrillation during daily activity and programmed exercise: a crossover open-label study of five drug regimens

Cost-effective strategies in the acute management of atrial fibrillation

Atrial fibrillation is the most common sustained arrhythmia likely to be encountered in clinical practice. It is associated with significant morbidity and mortality. The treatment of patients with atrial fibrillation can be complex and costly, especially when patients are hospitalized for acute management of this arrhythmia. In this review, we summarize current approaches to the acute management of atrial fibrillation with an emphasis on the most cost-effective approaches. We review acute methods of heart rate control and cardioversion, including pharmacologic and other minimally invasive strategies. We believe that the most cost-effective approaches may require the use of standardized clinical pathways. This may help to ensure that patients with acute atrial fibrillation receive the most effective and efficient care.

Mortality reduction by antiadrenergic modulation of arrhythmogenic substrate: significance of combining beta blockers and amiodarone

Over the last 3 decades, there have been numerous experimental and clinical studies that utilized beta blockers for acute as well as chronic myocardial syndromes, especially in the setting of myocardial infarction in which the focus has been on mortality reduction. The results of these studies demonstrated the benefits of these agents at all stages of coronary artery disease. Although these data have always indicated that beta blockade per se is an antiarrhythmic as well as an antifibrillatory mechanism, the recognition of this phenomenon has been slow in finding universal appreciation. More recent studies have evaluated the additive role of beta blockers to newer therapies. A number of investigations have now established that this class of drugs does exert antifibrillatory action in preventing the occurrence of ventricular tachycardia (VT) and ventricular fibrillation (VF), thereby reducing sudden arrhythmic death and prolonging survival. It is of interest that 2 of the leading antiarrhythmic drugs, amiodarone and sotalol, also have antiadrenergic properties. This article reviews the expanding role of beta-blocking drugs in the control and prevention of life-threatening ventricular tachyarrhythmias with a particular focus on the evidence for synergistic benefits when they are combined with other interventions, especially amiodarone.

Antiarrhythmic agents for atrial fibrillation: focus on prolonging atrial repolarization

Atrial fibrillation (AF) has been the subject of considerable attention and intensive clinical research in recent years. Current opinion among physicians on the management of AF favors the restoration and maintenance of normal sinus rhythm. This has several potential benefits, including the alleviation of arrhythmia-associated symptoms, hemodynamic improvements, and possibly a reduced risk of thromboembolic events. After normal sinus rhythm has been restored, antiarrhythmic therapy is necessary to reduce the frequency of AF recurrence. In the selection of an antiarrhythmic agent, both efficacy and safety should be taken into consideration. Many antiarrhythmic agents have the capacity to provoke proarrhythmia, which may result in an increase in mortality. This is of particular concern with sodium-channel blockers in the context of patients with structural heart disease. Flecainide and propafenone are well tolerated and effective in maintaining sinus rhythm in patients without significant cardiac disease but with AF. Recent interest has focused on the use of class III antiarrhythmic agents, such as amiodarone, sotalol, dofetilide (recently approved), ibutilide (approved for chemical conversion of AF and atrial flutter), and azimilide (still to be approved) in patients with AF and structural heart disease. To date, amiodarone and sotalol still hold the greatest interest, and although controlled clinical trials with these agents have been few, a number are in progress and some have been recently completed. These agents are effective in maintaining normal sinus rhythm in patients with paroxysmal and persistent AF and are associated with a low incidence of proarrhythmia when used appropriately. Because of the relative paucity of placebo-controlled trials of antiarrhythmic agents in patients with AF, experience until recently has tended to dictate treatment decisions. Increasingly, selection of drug therapy is being based on a careful and individualized benefit-risk evaluation by means of controlled clinical trials, an approach that is likely to dominate the overall approach to the control of atrial fibrillation in the largest numbers of cases of the arrhythmia. Pharmacologic therapy is likely to be dominated by compounds that exert their predominant effect by prolonging atrial repolarization.