Cochrane for Clinicians

Putting Evidence into Practice

Pharmacologic Cardioversion for Atrial Fibrillation and Flutter

William E. Cayley, Jr., M.D., University of Wisconsin
Eau Claire Family Medicine Residency Program, Eau Claire, Wisconsin

The Cochrane Abstract on the next page is a summary of a review from the Cochrane Library. It is accompanied by an interpretation that will help clinicians put evidence into practice. William E. Cayley, Jr., M.D., M.Div., presents a clinical scenario and question based on the Cochrane Abstract, followed by an evidence-based answer and a full critique of the review.

Clinical Scenario

A 70-year-old man comes to the clinic for routine follow-up of hypertension and is found to have new atrial fibrillation of unknown duration.

Clinical Question

Should antiarrhythmic medications be used to restore sinus rhythm for patients with atrial fibrillation?

Evidence-Based Answer

There is no evidence that rhythm control in older patients with atrial fibrillation is more effective than rate control for improving patient-oriented outcomes.1

Practice Pointers

Atrial fibrillation increases the risk of mortality and stroke. Furthermore, diminished atrial filling of the ventricles and irregular ventricular contraction can reduce cardiac output, leading to palpitations, dyspnea, and dizziness. Whereas rate-control strategies for managing atrial fibrillation advocate medically slowing ventricular response to the fibrillating atrium and using anticoagulation to reduce stroke risk, rhythm-control strategies involve medical or electrical conversion to sinus rhythm to improve hemodynamics and symptoms and, theoretically, reduce stroke risk.

The two studies2,3 evaluated in this Cochrane review1 showed that in patients older than 60 years, use of a number of different medications (alone or combined) for pharmacologic cardioversion of atrial fibrillation-including amiodarone (Cordarone), quinidine, sotalol (Betapace), disopyramide (Norpace), and flecainide (Tambocor)-did not improve mortality rates or stroke rates compared with rate control using calcium channel blockers, beta blockers, or digoxin, alone or in combination. Moreover, 50 percent of strokes in patients receiving antiarrhythmics occurred while they were in sinus rhythm, and long-term maintenance of sinus rhythm was achieved in only 56 to 62 percent of patients. Thus, cardioversion of a fibrillating atrium to reduce stroke risk and eliminate the need for warfarin (Coumadin) therapy does not seem to be a reliable solution; long-term maintenance of sinus rhythm is difficult, and those who have successful cardioversion appear to need long-term anticoagulation.

Although concern has been raised that the use of antiarrhythmic medications for atrial fibrillation will increase the risk of malignant dysrhythmias, these were uncommon with rate-control and rhythm-control strategies in the two studies2,3 reviewed. Results of one of the studies2 suggested there may be an increased mortality risk with rhythm control in patients without heart failure, but the numbers of patients with heart failure were low, and definitive data on management of atrial fibrillation in the setting of heart failure are lacking. The same study2 also showed that older patients and those with coronary artery disease may be at higher risk of death with rhythm control compared with rate control.

This review1 provides further evidence in support of recent guidelines on the management of atrial fibrillation. The American College of Cardiology and the American Heart Association note that there is a paucity of evidence indicating restoration and maintenance of sinus rhythm is more beneficial than rate control, and that the data available suggest no definite advantage of one approach over the other.4 The American Academy of Family Physicians and the American College of Physicians go further, recommending rate control with chronic anticoagulation as the best strategy for most patients with atrial fibrillation.5 Both guidelines,4,5 however, state that rhythm control may be appropriate in certain situations, depending on specific patient characteristics such as the desire for symptom control or improvement in exercise tolerance.

An important limitation of this review1 is that the two studies2,3 evaluated focused mainly on patients older than 60 years without heart failure or ventricular dysfunction. Thus, it sheds little light on the management of atrial fibrillation in younger populations or in patients with heart failure.

For the routine management of atrial fibrillation, this review1 supports using rate control with anticoagulation primarily. If rhythm control is attempted, continued use of anticoagulation appears necessary to maintain a reduced risk of stroke.

This clinical content conforms to AAFP criteria for evidence-based continuing medical education (EB CME). EB CME is clinical content presented with practice recommendations supported by evidence that has been reviewed systematically by an AAFP-approved source. The practice recommendations in this activity are available online at http://www.cochrane.org/cochrane/revabstr/AB003713.htm.

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The Author

William E. Cayley, Jr., M.D., M.Div., is assistant professor at the University of Wisconsin Eau Claire Family Medicine Residency Program, Eau Claire, Wis., and practices at the Sacred Heart and Luther hospitals in Eau Claire.

Address correspondence to William E. Cayley, Jr., M.D., M.Div., Augusta Family Medicine Clinic, Eau Claire Family Medicine Residency, University of Wisconsin Department of Family Medicine, 617 West Clairemont, Eau Claire, WI 54701 (e-mail: bcayley@yahoo.com). Reprints are not available from the author.

REFERENCES

1. Cordina J, Mead G. Pharmacological cardioversion for atrial fibrillation and flutter. Cochrane Database Syst Rev 2005;(2):CD003713.

2. Wyse DG, Waldo AL, DiMarco JP, Domanski MJ, Rosenberg Y, Schron EB, et al, Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med 2002;347:1825-33.

3. Hohnloser SH, Kuck KH, Lilienthal J. Rhythm or rate control in atrial fibrillation-Pharmacological Intervention in Atrial Fibrillation (PIAF): a randomised trial. Lancet 2000;356:1789-94.

4. Fuster V, Ryden LE, Asinger RW, Cannom DS, Crijns HJ, Frye RL, 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 (Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation): developed in collaboration with the North American Society of Pacing and Electrophysiology. J Am Coll Cardiol 2001;38:1231-66.

5. Snow V, Weiss KB, LeFevre M, McNamara R, Bass E, Green LA, et al. Management of newly detected atrial fibrillation: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians. Ann Intern Med;139:1009-17.

Cochrane Briefs

clarissa kripke, m.d.

Duration of Therapy for Women with Uncomplicated UTI

Clinical Question

What is the most appropriate duration of therapy for uncomplicated urinary tract infections (UTIs) in women?

Evidence-Based Answer

Three days of antibiotic therapy is as effective as longer courses for treatment of uncomplicated UTIs in women.

Practice Pointers

Uncomplicated UTIs in women are one of the most common indications for antibiotics. To prevent resistance, antibiotics should be used judiciously; thus, it is important to determine the minimum duration of antibiotic therapy required for treatment to be effective.

Milo and colleagues reviewed 32 randomized controlled trials (with a total of 9,605 patients) comparing three days of oral antibiotic therapy with longer courses for women 18 to 65 years of age. Pregnant women and women with symptoms that suggest upper UTI (e.g., fever, flank pain, vomiting, positive blood cultures) were excluded.

For short- and long-term resolution of symptoms, the reviewers found no difference between a three-day antibiotic course and a course lasting five to 10 days. Longer courses were more effective at clearing the bacteria on follow-up culture but also caused more adverse effects, and it is not clear that bacterial clearance results in improved patient-oriented outcomes. Although data were limited, organisms cultured were not more likely to be resistant to antibiotics after treatment in either group. For most women, a three-day course of antibiotics is sufficient to treat symptoms.

The Institute for Clinical Systems Improvement (ICSI) guideline1 recommends treatment with double-strength trimethoprim/sulfamethoxazole (Bactrim DS, Septra DS), one tablet twice per day for three days; or trimethoprim (Proloprim) at a dosage of 100 mg twice per day for three days. For women who are allergic to these first-line medications, the ICSI guideline1 recommends ciprofloxacin (Cipro) at a dosage of 250 mg twice per day for three days, or nitrofurantoin (Macrobid) at a dosage of 100 mg twice per day for seven days. Telephone screening and prescription of treatment is appropriate if there are no complicating factors. In the office, urinalysis is adequate for evaluating symptoms.

Milo G, et al. Duration of antibacterial treatment for uncomplicated urinary tract infection in women. Cochrane Database Syst Rev 2005;(2):CD004682.

REFERENCE

1. Institute for Clinical Systems Improvement. Uncomplicated urinary tract infection in women. Bloomington, Minn.: Institute for Clinical Systems Improvement, 2004.

Tiotropium Effective in Treatment of COPD

Clinical Question

Is tiotropium (Spiriva) effective for treatment of chronic obstructive pulmonary disease (COPD)?

Evidence-Based Answer

In patients with moderate or severe COPD, tiotropium reduces exacerbations, hospitalizations, and symptom scores and improves health-related quality of life compared with placebo and ipratropium (Atrovent). However, more study is needed to determine tiotropium's role in the treatment of COPD compared with long-acting beta agonists.

Practice Pointers

The first-line treatment for patients with stable COPD is albuterol (Ventolin).1 For patients whose symptoms are not adequately controlled with albuterol, second-line options include tiotropium, salmeterol (Serevent), formoterol (Foradil), ipratropium, albuterol/ipratropium (Combivent), and levalbuterol (Xopenex). According to the Institute for Clinical Systems Improvement guidelines on COPD,1 tiotropium as a scheduled bronchodilator has significant advantages for patients whose symptoms are not controlled by albuterol.

Tiotropium is a once-daily inhaled selective anticholinergic medication for COPD. It is related to ipratropium but costs around $115 per month, whereas ipratropium (two to four puffs four times per day) costs around $67 per month. Tiotropium may be taken in conjunction with theophylline, steroids, or beta agonists, but it has not been studied with ipratropium. Tiotropium is renally excreted, and dry mouth is the most common adverse effect.

To compare the effectiveness of tiotropium with other treatments, Barr and colleagues reviewed the literature and found nine randomized controlled trials with a total of 6,584 patients. They found that, compared with treatment with placebo or ipratropium, 14 patients must be treated for one year with tiotropium to prevent one COPD exacerbation, and 30 need to be treated to prevent one hospitalization. Tiotropium was more effective than placebo or ipratropium but not more effective than long-acting beta agonists regarding improvement in symptoms or quality of life. There was no statistical difference between exacerbation and hospitalization rates for patients treated with tiotropium compared with long-acting beta agonists.

Tiotropium shows promise as a first-line scheduled bronchodilator, but longer trials and trials comparing tiotropium with long-acting beta agonists are needed.

Barr RG, et al. Inhaled tiotropium for stable chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2005;(2):CD002876.

REFERENCE

1. Institute for Clinical Systems Improvement. Chronic obstructive pulmonary disease. Bloomington, Minn.: Institute for Clinical Systems Improvement, 2004.

The series coordinator for AFP is Clarissa Kripke, M.D., Department of Family and Community Medicine, University of California, San Francisco.

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