Atrial fibrillation: Ways to refine your care

,

Applied Evidence

Atrial fibrillation: Ways to refine your care

J Fam Pract. 2009 February;58(2):64-72

By

Shobha Rao, MD

What’s best for your patient: rate or rhythm control? Aspirin or warfarin? These guidelines and tools can help you decide.

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References

1. Fuster V, Ryden LE, Cannom DS, et al. ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation: 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 (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation. 2006;114:e257-354.

2. Benjamin EJ, Wolf PA, D’Agostino RB, et al. Impact of atrial fibrillation on the risk of death: the Framingham Heart Study. Circulation. 1998;98:946-952.

3. Wolf PA, Abbot RD, Kannel WB. Atrial fibrillation as independent risk factor for stroke: the Framingham Study. Stroke. 1991;22;983-988.

4. Singer DE, Albers GW, Dalen JE, et al. Anti-thrombotic therapy in atrial fibrillation: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(3 suppl):s429S-s456.

5. Kannel WB, Wolf PA, Benjamin EJ, et al. Prevalence, incidence, prognosis, and predisposing conditions for atrial fibrilllation: population-based estimates. Am J Cardiol. 1998;82(8A):2N-9N.

6. Prystowsky EN. Tachycardia-induced tachycardia: a mechanism of initiation of atrial fibrillation. In: DiMarco JP, Prystowsky EN, eds. Atrial Arrhythmias: State of the Art. Armonk, NY: Futura Publishing; 1995:123-149.

7. Cooke G, Doust J, Sanders S. Is pulse palpation helpful in detecting atrial fibrillation? A systematic review. J Fam Pract. 2006;55:130-134.

8. Nattel S, Opie LH. Controversies in atrial fibrillation. Lancet. 2006;367:262-272.

9. Wyse DG, Waldo AL, DiMarco JP, 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;347:1825-1833.

10. Hohnloser SH, Kuck KH, Lilienthal J. Rhythm or rate control in atrial fibrillation—Pharmacological Intervention in Atrial Fibrillation (PIAF): a randomised trial. Lancet. 2000;356:1789-1794.

11. Carlsson J, Miketic S, Windeler J, et al. Randomized trial of rate-control versus rhythm-control in persistent atrial fibrillation: the Strategies of Treatment of Atrial Fibrillation (STAF) study. J Am Coll Cardiol. 2003;41:1690-1696.

12. Van Gelder IC, Hagens VE, Bosker HA, et al. A comparison of rate control and rhythm control in patients with recurrent persistent atrial fibrillation. N Engl J Med. 2002;347:1834-1840.

13. de Denus S, Sanoski CA, Carlsson J, et al. Rate vs rhythm control in patients with atrial fibrillation: a meta-analysis. Arch Intern Med. 2005;165:258-262.

14. Corley SD, Epstein AE, DiMarco JP, et al. Relationships between sinus rhythm, treatment, and survival in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Study. Circulation. 2004;109:1509-1513.

15. Vora A, Karnad D, Goyal V, et al. Control of rate versus rhythm in rheumatic atrial fibrillation: a randomized study. Indian Heart J. 2004;56:110-116.

16. National Institute for Health and Clinical Excellence. National Collaborating Centre for Chronic Conditions. Atrial Fibrillation: National Clinical Guideline for Management in Primary and Secondary Care. London: Royal College of Physicians, 2006.

17. McNamara RL, Bass EB, Miller MR, et al. Management of new onset atrial fibrillation. Evid Rep Technol Assess (Summ). 2000;May(12):1-7.

18. Prystowsky EN. Atrial fibrillation. In: Topol EJ, ed. Textbook of Cardiovascular Medicine. Philadelphia: Lippincott Williams & Wilkins;1998:1661.

19. Roy D, Talajic M, Nattel S, et al. Rhythm control versus rate control for atrial fibrillation and heart failure. N Engl J Med. 2008;358:2667-2677.

20. Coplen SE, Antman E, Berlin JA, et al. Efficacy and safety of quinidine therapy for maintenance of sinus rhythm after cardioversion. A meta-analysis of randomized control trials. Circulation. 1990;82:1106-1116.

21. Roy D, Talajic M, Dorian P, et al. Amiodarone to prevent recurrence of atrial fibrillation. Canadian Trial of Atrial Fibrillation Investigators. N Engl J Med. 2000;342:913-920.

22. Hart RG, Pearce LA, Aguilar MI. Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation. Ann Intern Med. 2007;146:857-867.

23. Aguilar MI, Hart R, Pearce LA. Oral anticoagulants versus antiplatelet therapy for preventing stroke in patients with non-valvular atrial fibrillation and no history of stroke or transient ischemic attacks. Cochrane Database Syst Rev. 2007;(3):CD006186.-

24. Gage BF, Waterman AD, Shannon W, et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA. 2001;285:2864-2870.

25. Wazni OM, Marrouche NF, Martin DO, et al. Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of symptomatic atrial fibrillation: a randomized trial. JAMA. 2005;293:2634-2640.

Practice recommendations

Pursue a rate-control strategy for most patients with atrial fibrillation (AF); rhythm control may be preferable for younger (<65 years) symptomatic patients (A).
Use a risk stratification scheme to guide decisions regarding anticoagulation therapy; adjusted-dose warfarin is extremely effective at preventing strokes in patients with AF (A).
Hemodynamically unstable patients require urgent cardioversion, so you should not delay the procedure in order to provide anticoagulation therapy (C).

Strength of recommendation (SOR)

Good quality patient-oriented evidence
Inconsistent or limited-quality patient-oriented evidence
Consensus, usual practice, opinion, disease-oriented evidence, case series

Atrial fibrillation (AF), the most common arrhythmia seen in clinical practice, affects an estimated 2.2 million American adults.¹ The condition is associated with a 1.5- to 1.9-fold mortality risk independent of other risk factors² and about a 4- to 5-fold increase in the risk of strokes.³ Achieving rate control; restoring or maintaining sinus rhythm, when it’s feasible; and preventing stroke are the primary goals in treating patients with AF. Yet many physicians are not always sure about the best ways to achieve them.

Failure to provide adequate anticoagulation therapy—despite clear evidence that anticoagulation significantly reduces the risk of thromboembolic complications—may be the most common misstep physicians make in treating AF.⁴ But anticoagulation is not the only trouble spot. Choosing between a rate-control and rhythm-control strategy also has its share of challenges, as does deciding which drugs are best for which patients.

FAST TRACK

During AF, maintaining a ventricular rate of 60 to 80 bpm at rest and 90 to 115 bpm during exercise is recommended.

AF is an age-related condition, with the prevalence increasing from 0.5% among individuals <60 years old to 9% of those >80.⁵ An aging population will make your ability to manage AF even more critical in the years ahead. The text and tables that follow will help you refine your care. But first, a quick review.

Classification, causes, and clinical features

AF is classified primarily on the basis of duration:

Paroxysmal AF is the term for brief episodes (lasting <24 hours) and episodes that last up to 7 days but terminate spontaneously. Cardioversion is not needed for this self-limiting condition.

Persistent AF lasts longer than 7 days, and often requires electrical or pharmacological cardioversion.

Permanent AF is used to describe instances in which cardioversion has failed (or has not been attempted) and the arrhythmia is continuous.

These categories are not mutually exclusive—a patient may primarily have paroxysmal AF, with an occasional episode of persistent AF. The term recurrent AF is used when 2 or more episodes of paroxysmal or persistent AF occur.

Warfarin or aspirin? An anticoagulation risk tool

CHADS₂ is a validated risk stratification scheme that offers help in making decisions about anticoagulation therapy. Each of the letters in this acronym represents a risk factor, and carries a certain number of points:

Congestive heart failure (1 point)
Hypertension (1 point)
Age >75 years (1 point)
Diabetes (1 point)
Stroke (2 points)

Patients with a score of ≥3 are at high risk and need to be treated with warfarin; those with a score of 0 are at low risk and can be managed with aspirin. For patients with a score of 1 or 2, the choice of warfarin or aspirin should be based on clinician assessment and patient preference.

Source: Gage BF, et al. JAMA. 2001.²⁴

AF typically linked to heart conditions—but not always

Chronic cardiac conditions commonly associated with AF include ischemic heart disease, congestive heart failure (CHF), hypertension, and rheumatic mitral valve disease. Recurrent AF may also be associated with atrial flutter, Wolff-Parkinson-White (WPW) syndrome, or atrioventricular (AV) nodal reentrant tachycardia. It is essential to recognize the presence of such conditions, because treatment of the primary arrhythmia may reduce or eliminate the incidence of recurrent AF. ⁶

FAST TRACK

Electrical cardioversion has a higher success rate than pharmacological cardioversion, and is usually well tolerated.

There are also noncardiac causes of AF—eg, excessive alcohol intake (“holiday heart syndrome”), pulmonary embolism and other pulmonary diseases, and hyperthyroidism and other metabolic disorders. Lone AF, a term used when the patient is younger than 60 years of age and has neither clinical nor echocardiographic evidence of cardiopulmonary disease, is a diagnosis of exclusion. About 30% to 45% of cases of paroxysmal AF and 20% to 25% of persistent AF are considered to be lone AF.¹

EKG, x-ray, and echo: The role of each

Although some patients are asymptomatic, AF patients typically present with palpitations, dyspnea, fatigue, chest pain, or dizziness. A stroke may also be the first indication that a patient has AF.

A normal pulse rules out AF,⁷ and an irregular pulse should be an indication for an electrocardiogram (EKG). In most cases, a diagnosis can be made from the results of a 12-lead EKG. However, when diagnosis is uncertain or symptoms are paroxysmal, a Holter monitor or event recorder may be required.