Intraoperative mapping with a hand-held, roving
electrode requires a sustained rhythm lasting 5 to 10 minutes. To overcome this limitation, a computerized mapping system that records from 60 epicardial
electrodes simultaneously was used to study 16 patients with
Wolff-Parkinson-White syndrome. A sock containing 6 rows of
electrodes arranged concentrically from base to apex was place over the ventricles. The total time from placing the sock to analyzing the most basal row of
electrode recordings was 5 minutes. A 39 X 44-mm plaque containing 56
electrodes was than placed across the atrioventricular (AV) groove for detailed simultaneous mapping of the ventricle and atrium in the preexcited region identified from the most basal row of sock
electrodes. During plaque placement and recording, the remaining sock recordings were analyzed and a complete isochronal epicardial map was drawn. The plaque recordings were then analyzed. This technique rapidly detects early activation at the AV groove as do other computer systems using only a band of
electrodes around the AV groove. Also, complete epicardial mapping supplied important additional information. One patient with a posterior paraseptal accessory pathway had ventricular epicardial breakthrough below the strip recorded by the AV band. When more than 1 early activation site was present along the AV groove, complete maps allowed multiple pathways to be differentiated from normal activation fronts ascending from the bundle branches. Complete epicardial maps allowed the study of rapidly changing or short-lived electrical events including isolated premature impulses, initiation and termination of
reciprocating tachycardia by pacing, entrainment and changing degrees of fusion created by pacing during
reciprocating tachycardia, and ventricular responses during
atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)