Atrial Fibrillation: Progression is Deadly

A new analysis explores the characteristics of patients with permanent versus non-permanent atrial fibrillation, as well as those whose condition is controlled versus uncontrolled.

More than 2.2 million Americans have atrial fibrillation (AF). Patients with AF are more likely to have or develop multiple complications, including heart failure, coronary artery disease, valvular heart disease, diabetes mellitus, and hypertension. Experts tend to classify AF into four types: permanent AF (PermAF), and 3 types of non-permanent AF (nonPermAF): paroxysmal AF, persistent AF, and first episode (or not-yet-classified) AF. Over time, AF typically progresses from first episode, to paroxysmal, to persistent, and may eventually become “end-stage” or PermAF.

An analysis addressing AF subset characteristics and current management was published online on January 31, 2014, in PLoS One. Authored by a multinational team of researchers, it describes the distribution of AF in a large, geographically diverse contemporary sample.

The researchers used data from the Real-life Global Survey Evaluating Patients with Atrial Fibrillation (RealiseAF), an international, observational, cross-sectional survey including 10,491 participants. They found that 4869 (46%) of the participants had PermAF and 5622 (54%) had nonPermAF. They looked at participants’ CHADS₂ scores to estimate stroke risk. (A CHADS₂ score is a clinical prediction rule that assigns points to the presence of congestive heart failure, hypertension, age of at least 75 years, diabetes mellitus, or prior stroke, transient ischemic attack, or thromboembolism. A score of 2 or higher indicates moderate to high stroke risk.)

PermAF patients were more likely to be older and to have been diagnosed with AF longer. They also reported more symptoms and comorbidities (especially heart failure), and were less physically active than nonPermAF patients. PermAF patients had higher mean CHADS₂ scores (2.2 vs. 1.7 for nonPermAF patients) and were more likely to have a CHADS₂ score of at least 2 (67.3% vs. 53.0% for nonPermAF patients).

Among PermAF patients, 84.2% were prescribed a rate-control (as opposed to a rhythm-control) strategy, compared with 27.5% of nonPermAF patients. PermAF patients were more likely to be taking anticoagulants and medication for heart failure than were nonPermAF patients. However, PermAF patients were less likely to be taking statins and antiplatelet agents. Angiotensin receptor blocker use was similar in both groups.

Half of PermAF patients’ conditions were controlled, defined as being in sinus rhythm or in AF with a resting heart rate of at most 80 bpm. In controlled PermAF patients, the overall picture of health was better than in uncontrolled patients. Specifically, controlled PermAF patients had fewer symptoms, less severe heart failure, and fewer hospitalizations for acute heart failure than did uncontrolled patients, but had a greater number of arrhythmic events. They also tended to have lower BMIs and to be more active than uncontrolled PermAF patients.

The authors interpret their findings to indicate that as AF progresses from nonPermAF to PermAF, the number of associated comorbidities increases, especially those of cardiac origin. The analysis identified an unmet need for safe and effective rhythm-control treatments. Such treatments could control AF, minimize symptoms and complications, and potentially delay progression to PermAF. The researchers also identified an unmet need for rate-control treatments for PermAF. Adopting rate-control treatments could decrease heart failure, improve symptoms, and prevent complications.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.