Fig. 1

Patient flow, including planned sample size recalculation. *The initial sample size calculation resulted in 244 patients, which was readjusted in March 2011 after a pre-specified blinded sample size recalculation [16, 33]. Patients withdrawing consent prior to treatment were unaware of the assignment and were excluded from the population. Patients that refused a follow-up were contacted by phone to verify that they were alive, though no heart rhythm was obtained. RF, radiofrequency; CB, cryoballoon