Betas find another cardiology role
Betas find another cardiology role
Combo with digoxin favorable in AF treatment
For patients with chronic atrial fibrillation (AF), combining the beta blocker atenolol with digoxin therapy led to the best heart rate control, according to a February study of five regimens conducted at a California Veterans Administra tion Medical Center. (The American College of Cardiology is publishing the findings. See box, above right for contact information.)
Like its historical use in treating congestive heart failure, digoxin has long been a first-line monotherapy for AF treatment.
But according to research led by Bramah Singh, MD, of the VA Medical Center of West Los Ang eles, the most effective treatment combines digoxin and a beta blocker. To reach that conclusion, Singh and colleagues compared five regimens divided among 12 patients with chronic AF. The regimens included patients receiving digoxin; the calcium channel blocker diltiazem; the beta blocker atenolol; a combination of digoxin and diltiazem; or a combination of digoxin and atenolol.
The use of all three drugs as separate monotherapies did result in decreased heart rate and control, with digoxin surprisingly performing least effectively by itself, according to Singh. What’s more, as a monotherapy, the beta blocker outperformed the other drugs, he adds. But overall, and based on effective control over a 24-hour period, the beta-digoxin combination performed the best.
"Although digoxin has been very widely used, it is not very good at controlling the heart rate, especially during activities of daily living," says Singh. "The best control we achieved with a single drug was with the beta blocker, but when we combined it with digoxin, we achieved almost ideal control of the heart rate."
Singh says the way the two drugs work separately is the key to success. "Digoxin favorably modulates the parasympathetic nervous system, while atenolol blocks the effect of the sympathetic nervous system, which drives the heart rate. Together, the two drugs achieve a synergistic effect in which the total of their combined effects is greater than the sum of their individual effects."
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