Atrial fibrillation (AF) ablation has become widespread therapy in patients who are refractory to antiarrhythmic drugs. The complexity and cost of imaging and navigation ystems have led to development of custom-built ablation atheters. The 2 catheter technologies that currently seem to stablish themselves as viable alternatives are cryoballoon blation and phased radiofrequency (RF) ablation with multielectrode catheters. The safety of AF ablation has always been a concern because it is an elective procedure for a condition that is not directly life threatening. Among the adverse events that are most notable and may have long-term irreversible impact are stroke and transient ischemic attack (TIA), observed after respectively 0.23% and 0.71% of AF ablations. Over the last year, there have been a number of publications on a form of adverse event after ablation that was not previously appreciated. Diffusion-weighted magnetic resonance imaging (DW-MRI) can determine ischemia-induced changes in fluid shift over the cell membrane in the brain. After irrigated-tip RF ablation for AF, Gaita et al described discrete new ischemic lesions without any appreciable clinical symptoms. This phenomenon, called silent cerebral ischemia (SCI), was observed in 11^ to 14% of patients, with a possible relation to cardioversion or insufficient activated clotting time (ACT) levels during the procedure. Gaita et al compared the susceptibility to SCI of irrigated-tip ablation, cryoballoon, and pulmonary vein ablation catheter (PVAC) phased RF ablation. With DW-MRI before and directly after the procedure, it was found that PVAC ablation showed significantly more SCI than either irrigated-tip or cryoballoon ablation (38.9% vs 8.3% vs 5.6%), with a 1.48 higher relative risk. More recently in a similar study, Herrera et al reported that although the time