Special Feature
Atrial Fibrillation Management Pearls
By William J. Brady, MD, FACEP, FAAEM Dr. Brady is Professor of Emergency Medicine and Internal Medicine, Vice Chair, Emergency Medicine, University of Virginia, Charlottesville Dr. Brady reports no financial relationships with companies having ties to this field of study.
Several years ago as a medical student, I was wisely taught that the clinician should approach the patient with atrial fibrillation in the acute setting with the following thoughts in mind: 1) the patient’s hemodynamic state; 2) control of the ventricular rate; and 3) consideration of acute cardioversion. Certainly, nothing has changed regarding the consideration and classification of hemodynamic instability. The American Heart Association considers hemodynamic instability to be present if hypoperfusion is present on the examination.1,2 Hypoperfusion is potentially manifested by systemic hypotension, altered mentation, ischemic chest pain, dyspnea due to pulmonary congestion, or other signs of inadequate perfusion of the organs. Two matters warrant further comment regarding hemodynamic instability.
Clinical Decisions Can Be Complex
As Pollock wisely points out in his review of atrial fibrillation,3 the issue of instability is not a yes /no phenomenon. Rather, stability must be considered along a clinical spectrum—an atrial fibrillation spectrum ranging from an asymptomatic patient in whom the dysrhythmia is discovered incidentally, to the individual with new onset tachydysrhythmia in profound shock due to a rapid ventricular response. The emergency physician must consider numerous factors in this situation, including the clinical data characterizing the specific presentation as well as the patient’s comorbidity, particularly the presence of mitral valve disease, left atrial dilation, and left ventricular function.1,2 These features will affect treatment decisions in two important areas: the appropriate choice of therapeutic agents for rate control and probability of success of cardioversion in those patients identified as candidates for such therapy.
In unstable patients with new-onset atrial fibrillation who are profoundly unstable, urgent electrical cardioversion is the most appropriate therapy; this scenario, however, is uncommon. More often, new-onset atrial fibrillation will present less dramatically; such presentations include atrial fibrillation with a rapid ventricular response and a potential range of symptoms, including weakness, dizziness, palpitations, chest discomfort, and dyspnea. Recall that both chest discomfort and dyspnea are instability markers as noted by the American Heart Association.1,2 These complaints—if they are to be considered manifestations of true hemodynamic compromise, however—must be due to acute coronary ischemia and pulmonary edema, respectively. In situations where these symptoms are present, yet do not result from either process, the sensation of a rapid heart rate is the likely cause. In the stable though symptomatic patient, rate control is the primary management goal.
And, of course, the presence of atrial fibrillation in the hemodynamically compromised patient does not always translate into the dysrhythmia as the causative factor in the instability. Clearly, the new-onset atrial fibrillation presentation with rapid response and systemic hypotension is rather straightforward regarding the pathophysiology and necessary management issues. Much less clearly, however, is the patient with chronic atrial fibrillation who presents with hematemesis, rapid ventricular response, and systemic hypotension. At the bedside, the clinician must address and answer in timely fashion the physiologic question as to the source of the hypotension—hypovolemia resulting from the gastrointestinal hemorrhage, atrial fibrillation with rapid ventricular rate producing reduced ventricular filling, or a combination of both events.
The second consideration for the emergency physician in the atrial fibrillation patient is control of the ventricular response. Rate control by itself provides significant reduction in related symptoms. The continued presence of atrial fibrillation at a controlled rate, however, still may produce unwanted clinical manifestations. Recall that an organized atrial contraction contributes to ventricular filling; the loss of this so-called "atrial kick" may continue to produce unpleasant manifestations despite adequate rate control. Nonetheless, adequate rate control should be a primary issue for the emergency physician to address in the atrial fibrillation scenario in all patients. The borderline unstable patient also may be urgently treated with rate control rather than cardioversion initially. Rate control can be achieved relatively easily with calcium channel blockade or bet-adrenergic blockage; additional agents include digoxin, magnesium, or amiodarone.
The third and final consideration for the emergency physician regarding atrial fibrillation focuses on cardioversion. The primary question here is as follows: Must the emergency physician consider cardioversion in patients with new-onset atrial fibrillation? In the unstable presentation related directly to atrial fibrillation with rapid ventricular response, the answer to the question is: yes. The question is less easily answered in other, more common scenarios, such as the new-onset dysrhythmia presentation without significant adverse clinical effect. Numerous studies suggest that a significant portion of patients with new onset atrial fibrillation will spontaneously convert to sinus rhythm within 24 hours of onset and evaluation.4-8 This very high rate of spontaneous conversion coupled with the results of numerous atrial fibrillation trials demonstrating that rate control is similar to rhythm control in terms of several key endpoints.9,10 For instance, the AFFIRM and RACE trials demonstrated no significant difference in the occurrence of study endpoints representing quality-of-life issues, control of symptoms, and the occurrence of adverse events between the rate and rhythm control groups.9,10 As such, the patient with new onset atrial fibrillation who is stable certainly can be managed with rate control alone, either as an inpatient or outpatient depending upon certain other clinical variables.
References
1. Fuster V, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the European Society of Cardiology Committee for practice guidelines and policy conferences. Circulation 2001;104:2118-2150.
2. Adult Advanced Cardiac Life Support. ACLS Provider Manual. Dallas: American Heart Association; 2001.
3. Pollock G. Atrial fibrillation in the ED: Cardioversion, rate control, anticoagulation, and more. Emerg Med Prac 2002;4:1-28.
4. Falk RH, et al. Digoxin for converting recent-onset atrial fibrillation to sinus rhythm. Ann Intern Med 1987;106:503-506.
5. Jordaens L, et al. Conversion of atrial fibrillation to sinus rhythm and rate control by digoxin in comparison to placebo. Eur Heart J 1997;18:643-648.
6. Donovan KD, et al. Intravenous flecainide versus amiodarone for recent-onset atrial fibrillation. Am J Cardiol 1995;75:693-697.
7. Ergene U, et al. Must antidysrhythmic agents be given to all patients with new-onset atrial fibrillation? Am J Emerg Med 1999;17:659-662.
8. Digitalis in Acute Atrial Fibrillation (DAAF) Trial Group. Intravenous digoxin in acute atrial fibrillation: Results of a randomized, placebo-controlled multicentre trial in 239 patients. Eur Heart J 1997;18:649-654.
9. Olshansky B, et al. The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study: Approaches to control rate in atrial fibrillation. J Am Coll Cardiol 2004;43:1209-1210.
10. Hagens VE, et al. The RACE study in perspective: Rate control versus electrical cardioversion of persistent atrial fibrillation. The RACE study. Cardiac Electrophysiol Rev 2003;7:118-121.
Several years ago as a medical student, I was wisely taught that the clinician should approach the patient with atrial fibrillation in the acute setting with the following thoughts in mind: 1) the patients hemodynamic state; 2) control of the ventricular rate; and 3) consideration of acute cardioversion. Certainly, nothing has changed regarding the consideration and classification of hemodynamic instability.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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