BUFFALO, N.Y. — Anne B. Curtis, MD, Charles and Mary Bauer Professor and Chair of the University at Buffalo Department of Medicine in the School of Medicine and Biomedical Sciences, is a key contributor to the new guidelines for physicians, published last month, that incorporate the latest research on the best way to treat patients with atrial fibrillation.
Over the past decade, Curtis, one of the world’s leading clinical cardiac electrophysiologists and an expert in cardiac arrhythmias, has played an important role in developing national guidelines for treating atrial fibrillation.
The guidelines are issued by the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. They provide health-care providers with recommendations based on the most current research findings so that they can make the best treatment decisions for their patients.
In the Q&A below, Curtis explains how the guidelines will affect the way physicians treat patients with atrial fibrillation.
What is atrial fibrillation? Atrial fibrillation is a heart rhythm disorder that is manifested as a rapid, irregular heart beat that can cause symptoms such as fatigue, shortness of breath, exercise intolerance, and even lead to heart failure in some patients. It is the most common sustained type of irregular heartbeat observed in hospital patients.
How is atrial fibrillation normally treated? Atrial fibrillation is usually treated with medications to slow the heart rate, anti-arrhythmic drugs to keep the rhythm normal and anti-thrombotic drugs to prevent stroke. Anti-thrombotic drugs, or drugs to prevent blood clots from forming, are used because the fibrillating chambers of the heart can develop blood clots, which, if they break off and go to the brain, can cause stroke. All these efforts manage, but don’t cure, the arrhythmia. When nonsurgical treatment fails, atrial fibrillation can be treated with catheter ablation; however ablation does not always prevent recurrences or the need for additional procedures.
What was the purpose of the new guidelines, issued in January? The purpose of the 2011 American ACCF/AHA/HRS Focused Update on the Management of Patients with Atrial Fibrillation was to update the guidelines issued in 2006, in light of new research findings.
What is the most significant change in the new guidelines that patients should be aware of? The most significant change in the new guidelines has to do with catheter ablation, the minimally invasive surgical procedure used to treat patients with atrial fibrillation when they have not responded to medications. In catheter ablation, a catheter is threaded into a patient’s blood vessels and into the heart, where energy is applied to create scar tissue in defined areas to prevent abnormal electrical impulses from causing atrial fibrillation. The new guidelines establish this procedure as a class 1 recommendation for selected patients who have failed medical therapy. That is a stronger recommendation than it was in the 2006 guidelines, based on the fact that ablation is now considered a standard, rather than an experimental, procedure. This change is based on studies showing that ablation is effective in preventing recurrences of atrial fibrillation better than continued drug therapy.
What do you think was the most surprising change in the new guidelines? The most surprising change to me is based on recent research showing that strict control of the heart rate of patients with atrial fibrillation doesn’t seem to result in better outcomes than more lenient control. This recommendation was based on a study called RACE II, Rate Control Efficacy in Permanent Atrial Fibrillation, which found no difference in outcomes between patients who had strict control and those with more lenient control. It should be recognized, however, that in long-term follow-up, there was only a mean difference of nine beats per minute between the two groups. I believe it is still a disadvantage for patients to have very high heart rates in AF, say, over 120 beats-per-minute but, conversely, aggressively treating patients until the heart rate gets too slow, for example, much below 60-70 beats-per-minute, has disadvantages, too. One consequence could be that a patient might end up needing a pacemaker to prevent slow heart rates.
What other changes in the guidelines may affect how patients with AF are treated? A new anti-arrhythmic agent called dronedarone is now being recommended to prevent hospitalizations in patients with AF. In 2006, when the previous guidelines were issued, this drug wasn’t available yet.
What is the purpose of the additional update, issued this week? The purpose of this week’s update is to release a new guideline recommendation for a recently released anticoagulant, dabigatran. It is recommended as an alternative to warfarin for prevention of stroke in patients with atrial fibrillation who do not have serious valvular heart disease, an artificial heart valve or serious kidney or liver disease.
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