New guidelines take an evidence-based medicine
approach to atrial fibrillation
Atrial fibrillation (AFIB), affecting 0.4% of the total population, is a supraventricular
tachyarrhythmia caused by simultaneous discharge of multiple atrial foci. It
is the most common sustained arrhythmia encountered in clinical practice. Because
the prevalence of AFIB increases with advancing age, as many as 1% of individuals
over age 60 may be affected, and up to 6% of those over 80 years may present
with signs or symptoms.
The most common complaint from patients with AFIB is cardiac palpitation,
although fatigue, dyspnea, and dizziness are also reported. Some patients, however,
despite an irregular heart rhythm, are asymptomatic. And because diverse causes
underlie the etiology of AFIBand numerous diseases affecting cardiac tissues,
such as hypertension, congestive heart failure, and valvular heart disease,
are often present concomitantly with AFIBits treatment may be quite complex.
Because AFIB treatment is so complicated and patient-specific, new practice
guidelines were recently established by the American College of Cardiology (ACC),
the American Heart Association (AHA), and the European Society of Cardiology
(ESC). Their purpose is to offer assistance in clinical decision making by describing
a range of accepted approaches for diagnosing, managing, and preventing AFIB
and associated conditions. The guidelines are the first comprehensive practice
recommendations on AFIB to be published in several years.
Several algorithms for pharmacologic interventions are included in the guidelines
for managing patients with different types of AFIB. The algorithms can be followed
to determine not only if treatment is required but what type of
medication should be considered. For example, patients with newly discovered
AFIB may or may not require antiarrhythmic therapy, depending on whether the
irregular rhythm is paroxysmal or persistent. For paroxysmal AFIB, antiarrhythmic
therapy may be delayed, but anticoagulation may be indicated. In contrast, persistent
AFIB with disabling symptoms may require pharmacologic intervention to treat
the arrhythmia, to maintain cardiac rate control, and for anticoagulation. Other
algorithms in the new guidelines offer a step-by-step process for determining
which antiarrhythmic drugs are best for individuals in the face of other types
of heart disease.
"The new guidelines are well done, very complete, and up to date," said Jerry
Bauman, Pharm.D., FCCP, FACC, professor and interim head of the department of
pharmacy practice at the University of Illinois. One thing that sets them apart
from other documents published previously is that "the authors take a firm evidence-based
approach" toward clinical recommendations. The suggestions in the new ACC/AHA/
ESC guidelines are based primarily on published data and are ranked according
to whether the data were derived from multiple randomized clinical trials, nonrandomized
observational studies, or expert opinion.
Bauman also noted the prominent place dofetilide (Tikosyn, Pfizer) received
in the guidelines. According to Judy Cheng, Pharm.D., associate professor of
pharmacy practice at Arnold & Marie Schwartz College of Pharmacy & Health
Sciences at the Long Island University, "Dofetilide is the only new antiarrhythmic"
to be added since the last guidelines. "The new guidelines help to establish
the type of patient population for which the drug is best suited. Dofetilide
is one of the few drugs that can be used in heart failure patients," she said.
While both Bauman and Cheng are pleased with the new AFIB practice guidelines,
they believe that the current standards of practice for pharmacologic therapy
are already in line with them. However, the guidelines may result in changes
in the surgical management of AFIB, particularly with respect to surgical ablation.
Atrioventricular nodal ablation and permanent pacemaker implantation may be
considered for patients experiencing symptoms due to a rapid ventricular rate
during AFIB that is not adequately controlled with antiarrhythmic or negative
A full text version of the guidelines is available on the American College
of Cardiology Web site located at www.acc.org/clinical/statements.htm
and will also be published in the mid-October issue of the European Heart
Kelly Dowhower Karpa, R.Ph., Ph.D.
The author is a writer in the Philadelphia area.
Kelly Karpa. New guidelines take an evidence-based medicine approach to atrial fibrillation. Drug Topics 2001;19:32.