Atrial fibrillation (AF) is the most common form of arrhythmia, and there are a plethora of new devices and drugs to treat this burgeoning condition, along with its associated stroke risk. Yet, how these therapies will manifest within clinical practice has yet to be seen.
Sinus rhythm vs. rate control
Approximately 2.2 million people in the U.S. have AF, with about 160,000 new cases are diagnosed annually. After age 65, between 3 and 5 percent of people have AF, according to the Heart Rhythm Society (HRS). The condition costs approximately $6.65 billion annually in the U.S., largely due to increased hospitalization.
Traditionally, there are two approaches to the treatment of AF. One is cardioversion and anti-arrhythmic drugs to maintain sinus rhythm, and the other is the use of rate-controlling drugs, allowing AF to persist.
“Currently, we do not have a standard way to know the health-related quality of life [HrQol] of the patients,” says Valentin Fuster, MD, PhD, director of the Heart Center at Mount Sinai Medical Center in New York City. “Therefore, when we discern about the value of rate versus rhythm control, we haven’t clearly defined the patient from a symptomatic point of view.”
Fuster is calling for an international standardization of HrQol symptoms because choosing a strategy is highly influenced by how the patient feels.
Currently, clinicians tend to use generic HrQol questionnaires—most commonly the Short-Form health survey of 36 items—which “might not detect subtle, but important, HrQol changes in patients with AF,” wrote Fuster in a March editorial (Nature Rev 2010;7:115-116). Instead, he recommends using a disease-specific questionnaire or scale.
“To ensure that the debate progresses on whether rate or rhythm control is the better therapeutic strategy for patients with AF, and to enable us to make well-informed clinical decisions for individual patients with AF, the international AF community must agree on a standard, easy-to-use, AF-specific HrQol questionnaire,” Fuster wrote.
The AFFIRM trial has been most influential in informing physicians’ choices between sinus rhythm and rate control. The investigators concluded that the management of AF with the sinus rhythm control strategy offers no survival advantage over the rate control strategy, and there are “potential advantages,” such as a lower risk of adverse drug effects, with the rate control strategy (N Engl J Med 2002;347(23):1825-1833).
Eric N. Prystowsky, MD, director of the electrophysiology lab at St. Vincent Hospital in Indianapolis, says AFFIRM resulted in a “big misunderstanding” for the daily management of AF patients. He notes that AFFIRM was one of the many studies to assess the different strategies. “These studies focused on an elderly population, who could symptomatically be enrolled in either treatment strategy,” says Prystowsky, suggesting that the same strategy shouldn’t be applied to all AF patients. Almost 45 percent of the eligible patients in AFFIRM, according to the entry criteria, were excluded, largely because of physician and patient choice.
“Due to its exclusionary criteria, AFFIRM doesn’t really inform practitioners how to manage symptomatic AF patients,” says Robert C. Kowal, MD, PhD, a cardiac electrophysiologist at Baylor Heart and Vascular Hospital in Houston.
Rate control is easier to maintain compared with trying to keep a patient in sinus rhythm, so many practitioners default to this strategy, says Prystowsky. “Also,” he adds, “the trial did not find that rate control is superior to rhythm control, but rather that the two strategies were neutral.”
However, Prystowsky points out that the percentage of patients who are non-responsive to rate control decreases as they age. “If patients are more sedentary, they tend to respond better to a rate control strategy,” he says. “However, younger patients with paroxysmal AF—typically younger than 65 years—often desire a better strategy.”
Kowal concurs that sinus rhythm is “generally superior to rate control, but the problem is how physicians achieve sinus rhythm. If we had better modalities or therapies than anti-arrhythmic drugs to establish sinus rhythm with a high frequency and a high durability, then sinus rhythm would begin to show superiority to rate control in trials.”
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“In the past, it was believed that non-valvular AF stroke