SUPRAVENTRICULAR TACHYCARDIA INITIATED AND TERMINATED BY A SINGLE ELECTRICAL STIMULUS

In a patient with normal atrioventricular conduction, a Supraventricular tachycardia was repeatedly initiated and terminated by a single premature atrial beat. During the tachycardia, the atrial to His bundle activation time (A-H time) of the His bundle electrogram increased (P-R interval prolonged), and the polarity of the P wave remained unaltered. These observations suggest the creation and abolition of a circus movement of an unusual type, probably solely intraatrial, by a single premature atrial beat. © 1969.