This work studied different aspects of phased radiofrequency ablation based on data from a total of 159 patients who underwent the procedure for paroxysmal or persistent atrial fibrillation. We demonstrated that the procedure is safe with no significant learning curve effect only on fluoroscopy times, but not on complication rates, procedure time and acute isolation rate of the pulmonary veins. In a subset of 27 patients the rate of silent cerebral ischemia (SCI) was assessed by comparing the results of diffusion-weighted magnetic resonance imaging of the brain before and after the ablation and correlated with the number of microemboli recorded during different stages of the procedures using transcranial Doppler. New SCI on DW-MRI after PVI was demonstrated in 6 patients (22%) with a tendency to disappear by the 3-month follow-up control with the exception of one patient who still had a detectable lesion significantly reduced in size. No significant difference in the total number of microemboli was detected in those patients who demonstrated a new acute MRI lesion versus in those who had no new lesion. However, the number of microemboli recorded during PV angiography was significantly higher in the patients with versus in those without new brain lesions. Further, multivariate logistic regression results demonstrated that the total MES count detected during the entire procedure was predictive of silent cerebral lesions at an advanced age: patients aged 68 years or older were significantly more likely, to have new brain lesions if the number of MESs was high.