Epicardial mapping of patients undergoing surgical correction of the Wolff-Parkinson-White syndrome is usually accomplished by using a single point probe. This somewhat tedious and time consuming method has been streamlined by computer-based systems allowing multiple simultaneous point maps to be developed either by electrodes applied as a band around the atrioventricular groove or a sock over the ventricle. Because the computer technology required to access, analyze, and display this data is not widely available, a system was devised to display ten simultaneous electrograms from a wrap of ten electrodes placed about the atrial or ventricular side of the atrioventricular groove. Using this technique three patients undergoing surgery for accessory pathway removal were accurately and quickly mapped allowing surgical cure of the preexcitation in each case.