Fibrilacion Atrial (7)

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REVIEW

The Patient with Atrial Fibrillation Julia Heisler Indik, MD, PhD, Joseph S. Alpert, MDSarver Heart Center, College of Medicine, University of Arizona, Tucson.

ABSTRACT

Atrial fibrillation is a frequently encountered arrhythmia, particularly affecting the elderly. Patients at

significant risk for stroke should be considered for anticoagulation with warfarin. Management of atrial

fibrillation revolves around either controlling the ventricular rate response or trying to maintain sinus

rhythm with either pharmacologic or nonpharmacologic therapies. There are many treatment options to

consider, based upon the patient’s expectations, symptoms, and comorbid conditions. Therefore, the

treatment of atrial fibrillation must be individualized.

© 2009 Elsevier Inc. All rights reserved. • The American Journal of Medicine (2009) 122, 415-418

KEYWORDS: Ablation; Antiarrhythmic medication; Anticoagulation; Atrial fibrillation; Stroke

Atrial fibrillation is the most common sustained arrhythmia

in North America and Europe. In the United States, atrial

fibrillation affects approximately 2.2 million adults whose

median age is 75 years, and nearly 10% of individuals over

the age of 80 years, with a clear increase in incidence and

prevalence with age.1,2 During the late 20th century, the

Framingham Heart Study population demonstrated a 7.8%

prevalence of atrial fibrillation in men aged 65-74 years,

with a corresponding prevalence in men aged 75-84 years of 11.7%. As the population of older individuals has increased,

the prevalence of atrial fibrillation also has grown.1-3 How-

ever, even age-adjusted prevalence of atrial fibrillation has

increased in recent years, suggesting that age alone does not

account for all aspects of the increased frequency of en-

countering this arrhythmia.3

Atrial fibrillation occurs approximately 1.5 times more

frequently in men than in women. In the Framingham Heart

Study, the prevalence of atrial fibrillation in men without a

prior myocardial infarction was 8.7%. A similar cohort of

women had a prevalence of atrial fibrillation of only 5.2%.

Despite the sex difference in prevalence, the overall numberof female patients with atrial fibrillation exceeds the number

of men with this condition because of greater longevity in

women. Thus, the most common hospitalized patient with

atrial fibrillation in US hospitals is an elderly woman.

The majority of patients with atrial fibrillation have some

form of cardiovascular disease. Common cardiovascular

conditions predisposing to atrial fibrillation include hyper-

tension, valvular heart disease (especially mitral valve dis-

ease), arteriosclerotic heart disease with and without a prior

myocardial infarction, pericardial disease, and heart failure.Noncardiovascular diseases that predispose to atrial fibril-

lation include diabetes mellitus, hyperthyroidism, acute and

chronic alcohol abuse, and a variety of pulmonary diseases

such as chronic obstructive lung disease, pneumonia, and

pulmonary embolism. Finally, iatrogenic causes of atrial

fibrillation include cardiac and noncardiac surgery as well

as therapy with bronchodilating beta agonists, nonprescrip-

tion cold remedies, antihistamines, and local anesthetics.4

Recent investigation has revealed that inflammation in the

atria might play an important role in the initiation, mainte-

nance, and perpetuation of atrial fibrillation.5 Unfortunately,

the underlying etiology of atrial fibrillation is often not wellunderstood in individual patients, although there is increasing

evidence for a genetic predisposition.6 Families with auto-

somal dominant inheritance of atrial fibrillation have been

reported.7 In familial forms of atrial fibrillation, mutations have

been described affecting both potassium and sodium channels,

with associations with other inherited rhythm disorders such as

Brugada syndrome, short QT syndrome, and, most recently, in

a form of long QT syndrome.8

Idiopathic or “lone” atrial fibrillation is not as benign an

entity as once thought. Jouven et al observed a 4-fold

Funding: There are no funding sources for this manuscript.

Conflicts of Interest: There is no conflict of interest to disclose from

Dr. Indik or Dr. Alpert.

Authorship: Both authors had access to the data and content of this

manuscript and had a role in the writing of the manuscript.

Requests for reprints should be addressed to Julia Heisler Indik, MD,

University of Arizona, Sarver Heart Center, 1501 N. Campbell Ave.,

Tucson, AZ 85724.

E-mail address: [email protected]

0002-9343/$ -see front matter © 2009 Elsevier Inc. All rights reserved.

doi:10.1016/j.amjmed.2008.12.012

mailto:[email protected]

mailto:[email protected]



increase in cardiovascular mortality and a 2-fold increase in

all-cause mortality for middle-aged French men with lone

atrial fibrillation.9 A recent community-based study from

Omstead County in Minnesota and the EuroHeart Failure

Survey demonstrated that patients with newly diagnosed

atrial fibrillation with or without

heart failure had a high mortality

risk as well as prolonged hospital-ization, especially within the first

4 months following diagnosis.10,11

Of further concern are recent re-

ports that atrial fibrillation in pa-

tients without any evidence of

stroke are associated with memory

impairment, dementia, and hip-

pocampal atrophy.12,13 In patients

with paroxysmal atrial fibrillation,

a precipitating event, for example,

binge drinking, heavy exertion, or

emotional upset, can be identifiedin approximately 40% of individ-

uals.14 The most common precip-

itant was exercise, present in nearly 19% of patients, fol-

lowed by eating in 8%. Caffeine-containing beverages

precipitated atrial fibrillation in only 2.4% of patients.

The diagnosis of atrial fibrillation is usually straightfor-

ward, depending on the recognition of a randomly irregular

heart rhythm on physical exami-

nation or electrocardiogram. Atrial

fibrillation is further characterizedby whether it terminates spontane-

ously, “paroxysmal atrial fibrilla-

tion,” or requires cardioversion to

restore sinus rhythm, “persistent

atrial fibrillation.” There are 2 po-

tential strategies to manage atrial

fibrillation: control of the ventric-

ular heart rate, or restoration of

sinus rhythm. In patients over the

age of 65 years with at least one

risk factor for stroke, the Atrial

Fibrillation Follow-up Investiga-tion of Rhythm Management

(AFFIRM) trial demonstrated that

Figure 1 To employ a rate control strategy to manage atrial fibrillation, patients should first be

assessed for the risk for stroke to determine the need for anticoagulation. For patients with rapid

ventricular rates in atrial fibrillation, AV nodal blocking medications are utilized, which include

beta-blockers, calcium channel blockers, and digoxin. Pacemaker and AV node ablation is reserved

for patients who cannot be successfully managed medically. To employ a rhythm control strategy to

manage atrial fibrillation, patients also should first be assessed for the need for anticoagulation.

Antiarrhythmic drug (AAD) therapy and cardioversion are utilized as needed to maintain sinus

rhythm, and catheter ablation is reserved for patients who have symptomatic atrial fibrillation not

adequately controlled by pharmacologic therapy.

CLINICAL SIGNIFICANCE

● Atrial fibrillation is the most commonarrhythmia in this country, with a prev-

alence that has been increasing.

● Patients with atrial fibrillation need to beconsidered for the need for anticoagula-

tion, based upon their risk for stroke.

● Atrial fibrillation can be managed with

either rate or rhythm control strategies,

which are based upon both pharmaco-

logic and nonpharmacologic methods,

including catheter ablation.

416 The American Journal of Medicine, Vol 122, No 5, May 2009



there is no difference in survival using either a rate control

or rhythm control strategy.15 In the AFFIRM study, the rate

control strategy predominantly relied upon the use of atrio-

ventricular (AV) nodal blocking medications, while the

rhythm control strategy predominantly relied upon cardio-

version and the use of antiarrhythmic medications, most

commonly amiodarone. Whether rate and rhythm control

strategies are equivalent in younger patients (under the ageof 65 years) is unknown. Of note, newer techniques to

maintain sinus rhythm, including catheter ablation, were not

studied in the AFFIRM trial. Randomized trials are under-

way to assess whether ablation for atrial fibrillation can

favorably alter cardiovascular outcomes.

Which therapy strategy is chosen depends upon the

symptoms of the patient and comorbidities. In particular,

patients with infrequent symptoms may not require any

further treatment. However, many individuals have frequent

episodes of symptomatic atrial fibrillation, including fatigue

and dyspnea. Indeed, quality of life and exercise tolerance

are decreased in patients with atrial fibrillation, and both of these variables improve when sinus rhythm is restored.16

For rhythm control, many patients will require antiarrhyth-

mic drug therapy to maintain sinus rhythm (Figure 1). An-

tiarrhythmic drugs include the Vaughn-Williams Class IC

agents, such as propafenone or flecainide, and Class III

agents such as sotalol, dofetilide, or amiodarone. The choice

of antiarrhythmic medication is dependent on whether there

is any other heart disease such as significant hypertrophy,

systolic heart failure, or coronary artery disease (Figure 2).

Dronedarone is a new antiarrhythmic drug—awaiting Food

and Drug Administration approval—that is related to ami-

odarone but without iodine on its aromatic ring, which isresponsible for the long-term toxicity of amiodarone.

Dronedarone may be approved for management in a broad

group of patients, except for severe systolic heart failure,

where there has been concern for an increase in mortality

seen in the Antiarrhythmic Trial with Dronedarone in

Moderate to Severe CHF Evaluating Morbidity Decrease

(ANDROMEDA) trial.17 Patients who are not adequately

controlled on an antiarrhythmic medication can be con-

sidered for catheter ablation for atrial fibrillation.18

Other patients hardly seem to notice when they are inatrial fibrillation, as long as their heart rate is controlled.

Pharmacologic options to achieve rate control include

digoxin, beta-blockers, and calcium channel blockers (Fig-

ure 1). If such medications are not tolerated or are ineffec-

tive, then pacemaker implantation with AV node ablation

can be considered. Ablation of the AV node does not restore

sinus rhythm, but controls the consequence of atrial fibril-

lation, a rapid ventricular heart rate. It should be noted that,

for rate control patients, digoxin therapy slows resting but

not exercise heart rate, and this agent does not prevent

recurrent episodes of atrial fibrillation, although beta-

blocker administration can accomplish this goal.19 Digoxinalso should be used cautiously in the elderly and in patients

with chronic kidney disease, as the drug is cleared by the

kidneys.

The presence of atrial fibrillation markedly increases the

patient’s risk for developing arterial embolism and stroke,

depending on the presence of other clinical conditions, such

as hypertension and diabetes. Consequently, most patients

with atrial fibrillation should receive antithrombotic therapy

with warfarin. Even patients in whom rhythm control is

established should continue on warfarin because silent ep-

isodes of atrial fibrillation may still be occurring, for exam-

ple, at night during sleep. The Cardiac Failure, Hyperten-sion, Age, Diabetes, Stroke (Doubled) (CHADS2) score was

developed to identify patients who are at high enough risk

Figure 2 Antiarrhythmic drug therapy is chosen according to whether the patient has

heart disease, including systolic heart failure, coronary artery disease, and substantial left

ventricular hypertrophy. Dronedarone, indicated in parentheses, may be approved as an

appropriate choice for a broad range of patients, except in those with systolic heart failure.

417Indik and Alpert Management of Atrial Fibrillation



for stroke to warrant anticoagulation with warfarin.20 Pa-

tients with 2 moderate risk factors (age over 75 years,

hypertension, diabetes, or heart failure) or one high risk

factor (prior stroke, prosthetic heart valve, or mitral steno-

sis) have an estimated risk of stroke of 3.1%-5.1% per year

and should be anticoagulated with warfarin.20 If the risk of

bleeding is markedly increased, then aspirin may be the

therapy of choice because hemorrhage is less common withthis agent than with warfarin.

The presence of atrial fibrillation can contribute to pa-

tient morbidity. A rapid ventricular response can produce

myocardial ischemia or even infarction in a patient with

underlying coronary artery disease. Whether atrial fibrilla-

tion worsens prognosis in patients with acute myocardial

infarction or new-onset heart failure has been the subject of

considerable debate. Interestingly, some studies have re-

ported that atrial fibrillation independently worsens progno-

sis in patients with heart failure or myocardial infarction,

whereas other observers have found no effect of associated

atrial fibrillation on outcomes.20-25Despite the generally worsened prognosis for patients with

atrial fibrillation, many patients do well for years and even

decades. Therefore, the prognosis for the individual patient is

variable. As noted earlier, excellent rate control with beta-

blockers, nondihydroperidine calcium blockers (diltiazem and

verapamil) and digoxin, along with anticoagulation and control

of other cardiovascular risk factors, can stabilize patients with

atrial fibrillation for years. In this regard, it is of interest that 2

studies have documented significant improvement in prognosis

for patients with atrial fibrillation treated during the 1990s as

compared with individuals managed during the 1980s.26,27 In

our own practice, we work hard with patients to assess theirsymptoms and expectations with regard to choosing a rate or

rhythm control strategy.

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418 The American Journal of Medicine, Vol 122, No 5, May 2009

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