Dr. Karch and colleagues describe the results of right atrial mapping with a 64-pole basket catheter during persistent, induced sustained, and nonsustained atrial fibrillation. One implication which may be gathered from their report is that as atrial fibrillation evolves from paroxysmal to chronic, its wavelets may become less organized with shorter atrial fibrillation intervals. Atrial fibrillation, for the most part (approximately 80%), is a left atrial disease. Measurements from the right atrium are probably secondary responses to the left atrial dirvers (either spontaneous or induced), which evolve from left-sided pulmonary veins. Their observation of a slower, more organized atrial fibrillation in the nonsustained (i.e. paroxysmal) group is consistent with the results that we (meaning ourselves and the EP community) have observed with respect to atrial fibrillation ablation. Specifically, the slower and more organized the tachycardia (supraventricular or ventricular in origin), the more likely the success. Similarity, with atrial fibrillation ablation using a double trans-septal technique, we are able to achieve a cure rate of approximately 80% in the paroxysmal group, but only 50-60% in the chronic group. In closing, Karch and colleagues basket cases in the right atrium during atrial fibrillation is interesting, but not necessarily useful for most atrial fibrillation ablations. Operators have used the basket catheter and its splines in the left atrium (i.e. trans-septal) to map and isolate the pulmonary veins. This technique involves the placement of an appropriate sized basket partially into the pulmonary vein orifice. The exact contact and orifice location can be observed from electrogram analysis and anatomic distortion on fluoroscopy (i.e. circumferential indentation of the basket. So don t become a basket case over mapping the right atrium during atrial fibrillation; rather, focus on the left atrium for your atrial fibrillation ablations.