[Variation of body surface QRST isointegral map in patients with idiopathic long QT syndrome].

Body surface QRST isointegral maps in patients with long QT syndrome (LQTS) often show multipolar distribution. We recorded body surface maps in eight cases with LQTS. There were same day variations in the distribution of multipolarity and unipolarity in two of seven cases, and day-to-day variation in one of seven cases. In two of four cases, the distribution of the map changed from unipolarity to multipolarity following hand-pushing exercise. When two patients with same day variation or day-to-day variation were administered beta-adrenergic blocking agents, their QRST isointegral maps all showed unipolar distribution and had no variations. These findings suggest that QRST isointegral map can be a useful method for predicting the effectiveness of beta-adrenergic blocking drugs in idiopathic long QT syndrome.