Choices in the Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is more common as one gets older. It’s characterized by an irregular heart beat, which is often very rapid, and heart failure, as well as being a contributing cause, is a major complication. There are three main lines of treatment for AF:

1. anti-arrhythmic drugs (to correct the abnormal heart rhythm)
2. surgical ablation or destruction of a small area of abnormal heart muscle that’s responsible for the irregular rhythm, and
3. slowing of the heart rate by drug therapy.

Which one is best for which type of patient? That’s a critical question. A recent report in the New England Journal of Medicine compares the benefits and problems associated with controlling the heart’s rhythm (no. 1 above) with those of controlling the rate (no. 3) in patients with AF and heart failure.

In 1,376 patients who were enrolled and followed for an average of 3 years, the rate of cardiovascular death did not differ significantly between the rhythm-control (27%) and the rate-control (25%) groups. Overall mortality, stroke rates, and incidence of worsening heart failure were also similar.

In randomized trials in patients with AF but no heart failure, treatments that restore and maintain normal rhythm have not shown convincing advantages over those that simply control heart rate. However, patients in rhythm-control groups were more likely to be hospitalized in the first year after the start of the studies.

Is ablation superior to rhythm control by drugs (no. 2 vs. no. 1)? A debate between experts at the Cardiostim 2008 Meeting in France addressed this. So far there have been only 4 small controlled studies testing the benefits of ablation versus anti-arrhythmic drugs; these studies have shown the consistent superiority of ablation, with a Hazards Ratio of 3.7 in its favor.

In general, antiarrhythmic drugs are not very effective, and have some undesirable side effects. On the other hand, ablation techniques are comparatively new, with additional methods being tried constantly; there is no standardization, yet. There are relatively few centers that practice ablation, and insufficient trained cardiologists to treat all candidate AF patients this way. The risks have not been adequately characterized – one authority speaks of a 4% frequency of major complications.

The comparative benefits and costs of restoring normal rhythm in AF will become clearer in a few years. In the meantime, patients with AF in heart failure and a rapid pulse could probably do worse than have a trial of medications to slow their heart rate, as a first choice of treatment.