July 30, 2011

Chicago, IL - Many have been called, but few have been chosen—drugs, that is, to give patients undergoing CABG surgery for prevention of postoperative atrial fibrillation (AF). Amiodarone often works, but other drugs have been tried and fizzled in attempts to find a safer, shorter-acting alternative.

Now a single-center retrospective cohort study suggests that ranolazine (Ranexa, Gilead Sciences) might also be worth exploring for prevention of post-CABG AF[1]. Currently an antianginal for patients with stable CAD, ranolazine may have prevented some ventricular and supraventricular arrhythmias in MERLIN TIMI 36, a trial that found the drug ineffective in acute coronary syndromes.

The current study, from Dr Ronald H Miles (Aspirus Heart and Vascular Institute, Wausau, WI) and colleagues and published online July 4, 2011 in the American Journal of Cardiology, looked at 393 patients undergoing CABG at a single center from 2008 to 2010. Amiodarone or ranolazine had been initiated before the surgery and continued for 10 to 14 days afterward.

The prevalence of AF after CABG was significantly (p=0.035) reduced among patients who had received ranolazine compared with those getting amiodarone, while short-term clinical outcomes were similar.

Outcomes for patients undergoing CABG and AF prophylaxis with amiodarone or ranolazine

End point Amiodarone, n=211 (%) Ranolazine, n=182 (%) p
Post-CABG AF 26.5 17.5 0.035
30-d readmission 10.4 10.4 1.00
30-d mortality 1.09 0.94 0.88

In an analysis that controlled for age, sex, preoperative AF, heart failure, LVEF, MI history, CABG history, chronic lung disease, and use of beta blockers and ACE inhibitors or angiotensin receptor blockers, use of amiodarone, compared with ranolazine, carried an odds ratio (OR) of 1.7 (95% CI 1.01-2.91) for post-CABG AF (p=0.045). Other multivariate predictors included age (OR 2.2 for every 10 years, 95% CI 1.63-2.95; p<0.001) and chronic lung disease (OR 1.86, 95% CI 1.00-3.43; p=0.049).

The current study wasn't randomized or placebo controlled, the group notes, but "because amiodarone use has been shown to decrease AF after CABG, and we observed less AF with ranolazine, the present results seem particularly encouraging."

Senior author Dr David K Murdock (Aspirus Heart and Vascular Institute) discloses that he was a MERLIN investigator and formerly a consultant for Gilead Sciences; the other authors had no disclosures.


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