Strict heart rate control provides no advantage over lenient approach

December 20, 2010

Strictly controlling the heart rate of patients with atrial fibrillation provides no advantage over more lenient heart rate control, experts report in a focused update of the 2006 guidelines for the management of patients with atrial fibrillation.

The new recommendations, published in Circulation: Journal of the American Heart Association, the Journal of the American College of Cardiology, and HeartRhythm Journal, are updates of the American College of Cardiology/American Heart Association/European Society of Cardiology 2006 Guidelines for the Management of Patients With Atrial Fibrillation. The 2010 focused update allows experts to swiftly incorporate significant new findings into the guidelines.

Atrial fibrillation is an irregular heart rhythm that occurs when the heart's two upper chambers beat erratically, causing the chambers to pump blood rapidly, unevenly, and inefficiently. Blood can pool and clot in the chambers, increasing the risk of stroke or heart attack. More than 2 million Americans live with the condition.

The heart rate recommendation, one of several in the update, states that strict treatment to control a patient's heart rate (at less than 80 beats per minute at rest and less than 110 during a six-minute walk) is not beneficial over a more lenient approach to achieve a resting heart rate of less than 110 in patients with persistent, or continuous, atrial fibrillation with stable functioning of the ventricles, (the heart's lower chambers).

"The evidence showed rigid control did not seem to benefit patients," said L. Samuel Wann, M.D., chair of the focused update writing group and director of cardiology at the Wisconsin Heart Hospital in Milwaukee. "We don't need to be as compulsive about absolute numbers, particularly doing exercise tests and giving multiple drugs based solely on heart rate. Patients with symptoms due to rapid heart action need treatment, and the long term adverse effects of persistent tachycardia on ventricular function are still of concern."

The evidence-based updates, which reflect major advances in disease management, include:

Clopidogrel

A combination of aspirin and the oral antiplatelet drug clopidogrel "might be considered" to prevent stroke or other types of blood clots in atrial fibrillation patients who are poor candidates for the clot-preventing drug warfarin. Although warfarin remains effective, it requires patients to have regular testing to monitor its effectiveness and dosage adjustment. "It's a minor inconvenience for most, but a major inconvenience for some," Wann said.

Dronedarone

New research showed dronedarone, which is administered as a pill, could reduce hospitalizations for cardiovascular events related to atrial fibrillation. Dronedarone should not be given to patients with NYHA class IV heart failure or patients who have had an episode of decompensated heart failure in the past 4 weeks, especially if they have depressed ventricular function.

Dronedarone is associated with less hospitalizations and less side effects than amiodarone.

Catheter Ablation

Several new or revised recommendations support the role of catheter ablation as a treatment to maintain normal heart rhythm. In catheter ablation, a tube is inserted into a blood vessel and guided to the heart, where radiofrequency energy is applied that can destroy small areas of tissue responsible for an arrhythmia.

Ablation is useful when performed for selected patients at experienced centers (in which more than 50 cases are performed annually). For those patients with symptomatic paroxysmal atrial fibrillation (comes and goes on its own), who have not had success with drug treatment, do not have severe lung disease, and have a normal or mildly dilated left atrium and normal or mildly reduced function of the left ventricle, catheter ablation "is useful in maintaining sinus rhythm."

The treatment option is also reasonable for patients with symptomatic persistent atrial fibrillation, and it may be reasonable to treat symptomatic paroxysmal atrial fibrillation in patients with significant enlargement of the left atrium or with significant left ventricle dysfunction.

"Catheter ablation is one of the most rapidly growing procedural areas in cardiology right now, and the evidence does support that," Wann said.
-end-
Co-authors are: Anne B. Curtis, M.D.; Kenneth A. Ellenbogen, M.D.; N.A. Mark Estes III, M.D.; Michael D. Ezekowitz, M.B., Ch.B.; Warren M. Jackman, M.D.; Craig T. January, M.D.; James E. Lowe, M.D.; Richard L. Page, M.D.; David J. Slotwiner, M.D.; William G. Stevenson, M.D.; and Cynthia M. Tracy, M.D. Author disclosures are on the manuscript.

Statements and conclusions of study authors published in American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect the association's policy or position. The association makes no representation or guarantee as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at www.heart.org/corporatefunding.

The American College of Cardiology is transforming cardiovascular care and improving heart health through continuous quality improvement, patient-centered care, payment innovation and professionalism. The College is a 39,000-member nonprofit medical society comprised of physicians, surgeons, nurses, physician assistants, pharmacists and practice managers, and bestows credentials upon cardiovascular specialists who meet its stringent qualifications. The College is a leader in the formulation of health policy, standards and guidelines, and is a staunch supporter of cardiovascular research. The ACC provides professional education and operates national registries for the measurement and improvement of quality care. More information about the association is available online at http://www.cardiosource.org/ACC.

The American Heart Association is the nation's oldest and largest voluntary health organization dedicated to fighting heart disease and stroke. Our mission is to build healthier lives by preventing, treating and defeating these diseases. We fund cutting-edge research, conduct lifesaving public and professional educational programs, and advocate to protect public health. To learn more or join us in helping all Americans, call 1-800-AHA-USA1 or visit www.heart.org.

The Heart Rhythm Society is the international leader in science, education and advocacy for cardiac arrhythmia professionals and patients, and the primary information resource on heart rhythm disorders. Its mission is to improve the care of patients by promoting research, education and optimal health care policies and standards. Incorporated in 1979 and based in Washington, DC, it has a membership of more than 5,300 heart rhythm professionals in more than 72 countries around the world. www.HRSonline.org.

American Heart Association

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