Chicago, IL - Trends in antiarrhythmic management in the US have shifted toward amiodarone as the drug of choice for sinus-rhythm maintenance and away from digoxin for rate control. Despite decisive progress in the past decade, anticoagulation use is still unexpectedly low, with not even half of AF patients at risk for stroke being anticoagulated.1

Although oral coagulant use in creased, it remains concerning that many patients at high risk for stroke are not anticoagulated.

"Although oral-coagulant use increased, it remains concerning that many patients at high risk for stroke are not anticoagulated," the researchers, led by Dr Margaret Fang (University of California, San Francisco), state in their survey report in the January 12, 2004 issue of Archives of Internal Medicine.

The incidence of AF is increasing, currently affecting 2.3 million Americans. Fang and colleagues analyzed data from the National Ambulatory Medical Care Survey (NAMCS) from 1991 to 2000 to evaluate trends and changes in the management of AF over time, with a focus on three major therapeutic goals:

Control of rapid ventricular rate.

Restoration and maintenance of sinus rhythm.

Prevention of thromboembolic complications.

They expected digoxin to be largely replaced by beta blockers and calcium channel blockers and the use of anticoagulants and new sinus-rhythm medications, such as amiodarone, to have increased over time. They analyzed 1355 patient visits for AF in terms of prescribed medications and developed a multivariate model for independent predictors of drug use.

Agents for rate control remain the most commonly used medications in AF, and, as expected, the use of digoxin declined significantly, but it was not replaced by an equally significant increase in the use of beta blockers and calcium channel blockers. Studies had indicated that digoxin was less effective than beta blockers or calcium channel blockers in controlling effort-related tachycardia. "We were surprised that the decline in digoxin was not more offset by increases in the use of other medications for rate control," Fang et al write. Further studies, they point out, should determine whether this indicates an underuse of beta blockers and calcium channel blockers. The authors report no significant predictors of rate-control medication use. Sinus-medication use, on the other hand, was associated with male sex and visit to a cardiologist.

Marked shifts occurred in the use of sinus-rhythm medications, away from the use of quinidine and toward a rapid rise in prescriptions for amiodarone, with low cardiac toxicity and less need for initial electrocardiographic monitoring. "We expect that the results of recent trials comparing rate to rhythm control will slow this sharp rise in amiodarone use," the authors state.

Although antithrombotic therapy increased in general, especially the use of anticoagulants in patients 80 years or older, still fewer than 50% of patients at high risk for stroke received anticoagulants.