American College of Cardiology

* * Two atrial fibrillation treatments compared in the largest-ever trial of its kind

(ATLANTA)—One of the largest-ever comparisons of two methods for managing patients with atrial fibrillation, an abnormal rhythm of the heart’s smaller upper chambers, could change the way physicians treat an increasingly common health problem.

Normally the two upper heart chambers, the atria, efficiently pump blood into the two larger chambers, the ventricles. But atrial fibrillation impairs ventricular filling because the atrial muscle cells don’t contract in synchrony, which can sometimes lead to potentially fatal ventricular rhythms. Atrial fibrillation can also promote formation of clots that can trigger strokes. Physicians can use drugs to restore proper atrial rhythm (rhythm control) or, instead, to control the ventricular heart rate (rate control). But neither method has been shown to be safer or more effective than the other. That could change.

In the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM), more than 4,000 elderly patients with atrial fibrillation who were at high-risk for stroke or death were randomly managed with either rhythm control or rate control. All patients received blood thinners to lower the risk of stroke, which is standard therapy.

“AFFIRM is the largest trial of its kind ever conducted, and the first to use death as a primary outcome measure,” said Dr. D. George Wyse, of the University of Calgary in Alberta, Canada. Dr. Wyse is scheduled to present its results Monday, March 18, at 9:15 a.m. at the American College of Cardiology 51st Annual Scientific Session.

** Repeated shocks vs. rate-controlling medications in patients with atrial fibrillation

(ATLANTA)—Patients with atrial fibrillation, a common rhythm abnormality in the heart’s smaller upper chambers, called the atria, can be treated with either shocks or medications to restore normal atrial beats. But physicians may alternatively choose to restore adequate blood flow with drugs that regulate contractions of the heart’s lower chambers, the ventricles. Now a study has directly compared these methods—electrical shocks as needed to restore normal heart rhythm or drug therapy to control the rate of ventricular beats—to determine whether one or the other might serve patients better.

Normally the atria rhythmically and efficiently fill the ventricles with blood. But this process is impaired by atrial fibrillation, in which the atrial muscle cells contract in an uncoordinated way. Without effective treatment, the disorder can lead to the formation of clots that can cause strokes, or, occasionally, trigger abnormal ventricular rhythms that could become fatal.

The RACE study is the first study to compare electric-shock rhythm control and ventricular rate control only in patients with persistent atrial fibrillation—excluding patients with the less serious intermittent form of the rhythm abnormality, according to Dr. Isabelle C. Van Gelder, a lead investigator with the study. All patients in the RACE (Rate Control vs. Electrical Cardioversion for Persistent Atrial Fibrillation) study were given blood-thinning medications to help prevent stroke, observed Dr. Van Gelder, of the Interuniversity Cardiology Institute of The Netherlands, Utrecht.

RACE principal investigator Dr. Harry J. Crijns, of the University Hospital Maastricht in The Netherlands, is slated to disclose the trial’s findings Monday, March 18, at 9:30 a.m. at the American College of Cardiology 51st Annual Scientific Session.

Antibiotic/anti-inflammatory tested in patients with acute unstable chest pain or heart attack

(ATLANTA)—A randomized trial is testing whether long-term treatment with azithromycin, a macrolide antibiotic, can prevent death or further cardiac problems after unstable chest pain or acute heart attack in patients with prior infection by Chlamydia pneumoniae.

“Epidemiologic studies have suggested that there is some relationship between previous C. pneumoniae infection and coronary artery disease,” observed Dr. Bojan Cercek. Azithromycin can not only kill C. pneumoniae; it also appears to have anti-inflammatory effects, which prior studies suggest might benefit patients at risk of heart attacks, according to Dr. Cercek, of Cedars-Sinai Medical Center in Los Angeles.

In the Azithromycin in Acute Coronary Syndrome trial, 1,440 patients with prior C. pneumoniae exposure who developed an acute threatened or outright heart attack were randomly assigned to five days of treatment with the antibiotic or a placebo. If such antibiotic therapy is found to help reduce such patients’ risk of recurrent chest pain, further heart attacks, or death, then it could eventually become a standard treatment.

Dr. Cercek is slated to present results from the Azithromycin in Acute Coronary Syndrome trial Monday, March 18, at 9:45 a.m. at the American College of Cardiology 51st Annual Scientific Session.

Can an antibiotic help prevent second heart attacks in C. pneumoniae positive patients?

(ATLANTA)—Recent research suggests that certain bacteria may be involved in the development of heart disease, but whether antibiotics should have a treatment role in patients with heart disease is unknown. A randomized trial is examining whether targeted antibiotic treatment might prevent further problems in patients with a history of heart attack who also show evidence of prior infection by one of the implicated organisms, Chlamydia pneumoniae.

In the Weekly Intervention with Zithromax for Atherosclerosis and its Related Disorders (WIZARD) trial, more than 7,700 such patients were assigned to receive either azithromycin, known to have anti-Chlamydia activity, or a dummy placebo pill. If the trial shows that fewer patients who received azithromycin subsequently died or were less likely to experience repeat heart attacks or other heart disease events, it may mean that some antibiotics could play a significant role in the management of some patients with heart disease.

Dr. Michael W. Dunne, of Pfizer Inc., is scheduled to present the results of WIZARD Monday, March 18, at 10 a.m. at the American College of Cardiology 51st Annual Scientific Session.

(ATLANTA)—Chest pain caused by heart vessels partially obstructed by clots, which can rapidly turn into a full heart attack, is often treated with blood thinners along with aspirin or other anti-clotting drugs. A trial has now compared the traditional blood thinner heparin with a more recently developed derivative for safety and effectiveness in patients with such threatened heart attack who are also receiving eptifibatide, a powerful clot-preventing agent.

In the INTERACT (Integrelin and Enoxaparin Randomized Assessment of Acute Coronary syndrome Treatment) trial, more than 700 patients receiving eptifibatide were randomly assigned also to receive either traditional heparin or the low-molecular-weight heparin enoxaparin. Eptifibatide belongs to a class of agents, the glycoprotein IIb/IIIa receptor inhibitors, that directly discourage platelets from clumping into clots. They are sometimes called “super aspirins,” after the more familiar medication that keeps platelets apart less effectively. The INTERACT trial, researchers hope, will help show that the combination of eptifibatide and enoxaparin can be effective against threatened heart attacks without increasing the risk of bleeding.

The INTERACT trial is the largest-yet randomized trial of its kind, said Dr. Shaun G. Goodman, of St. Michael’s Hospital in Toronto, Canada. Dr. Goodman is slated to present its results Monday, March 18, at 10:15 a.m. at the American College of Cardiology 51st Annual Scientific Session.

The American College of Cardiology, a 28,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in development of standards and guidelines, and the formulation of health care policy.

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