ANN ARBOR—Up to 40 percent of patients who undergo open heart surgery suffer atrial fibrillation?a rapid, irregular beat in the upper chambers of the heart?in the days after the operation. Administering a cardiac drug called amiodarone for several days prior to surgery, however, reduces the likelihood of atrial fibrillation by approximately 50 percent, according to a study conducted at the University of Michigan Health System.

As a result of the amiodarone treatment, patients experienced less discomfort and the length and cost of hospitalization was reduced. The research findings appear in this week’s edition of the New England Journal of Medicine.

In the double-blind, randomized study, 64 patients were given oral doses of amiodarone for a minimum of seven days before elective heart surgery and 60 patients received a placebo. One in four of the patients who received the medication suffered atrial fibrillation after surgery, compared with 53 percent of the patients who were administered a placebo.

For patients receiving amiodarone:

• The mean length-of-hospital-stay was 6.5 days, compared with 7.9 days for the control group.

• When atrial fibrillation occurred, it was less severe, with a significantly lower maximum ventricular heart rate than the rate experienced by the placebo group.

• Hospital costs were several thousand dollars less per case.

In addition, reducing the occurrence of atrial fibrillation lowers the risk of stroke, which is a possible complication of atrial fibrillation, and decreases the need to shock the heart (defibrillation) to regulate the heartbeat.

“The amiodarone treatment resulted in less discomfort for patients and lower hospital costs,” said Fred Morady, M.D., a member of the U-M research team. “The next step is to determine if similar benefits can be achieved when the medication is administered in an accelerated dose over a shorter period of time.”

That’s important because heart surgery often must be performed quickly, without the luxury of a lengthy pre-operative treatment period. The required week-long treatment with amiodarone limits its widespread use for the prevention of atrial fibrillation following heart surgery.

The U-M research team included Morady,Adam Strickberger, M.D.; K. Ching Man, D.O.; Rajiva Goyal, M.D.; G. Michael Deeb, M.D.; Steven F. Bolling, M.D.; Francis D. Pagani, M.D.; Cynthia Bitar, R.N.; and Emile G. Daoud, M.D. (Daoud is now affiliated with Riverside Hospital in Columbus, Ohio). Marc D. Meissner, M.D., of Harper Hospital in Detroit also contributed to the study.

The project was partially funded by Wyeth-Ayerst Laboratories, which manufactures amiodarone under the trade name Cordarone.

Adam StrickbergerWyeth-Ayerst LaboratoriesU-M News and Information ServicesUniversity of Michigan