Ninety patients who underwent cardioversion of persistent atrial fibrillation (AF) were randomized to bisoprolol 5 to 10 mg once daily or carvedilol 12.5 to 25 mg twice daily. Using intention-to-treat analysis, 23 patients (46%) in the bisoprolol group and 17 patients (32%) in the carvedilol group relapsed into AF during the 1 year of total follow-up (p = 0.486). Patients treated with carvedilol had a 14% (hazard ratio 0.86) lower risk of relapse of AF compared with patients in the bisoprolol group, although results were statistically insignificant (p = 0.661) after controlling for patient age, gender, baseline heart rate, and left atrial diameter.