title: Study of P wave morphology in lead V1 during supraventricular tachycardia for localizing the reentrant circuit.
abstract: Paroxysmal supraventricular tachycardia (SVT) is a benign form of tachycardia that generally does not require costly evaluation. The purpose of this study was to describe a new sign permitting delineation of the mechanism of SVT by analysis of the P wave in lead V1 and the left atrial electrogram, which may be registered by the esophageal electrode. Among 146 patients with SVT, 72 had a ventriculoatrial interval greater than 70 msec. The P wave in lead V1 during SVT was discernible in 69 of them. The precession of the left atrial electrogram on the P wave in lead V1 was always associated with reentry through a left lateral (n = 37) or posteroseptal (n = 4) accessory atrioventricular (AV) connection. When the P wave in lead V1 preceded or occurred simultaneously with the left atrial electrogram, reentry was through either the AV node or a right-sided accessory AV connection. On the other hand, although the P wave in lead V1 was more frequently negative in reentry through a right-sided connection and positive in reentry through a left-sided connection, the polarity was not specific enough to identify the reentry. The precession of the left atrial electrogram recorded by the esophageal electrode on the P wave in lead V1 during SVT was a specific criterion of reentry through a left accessory AV connection, and this technique could be useful for preliminary localization of the accessory connection before electrophysiologic study.
authors.affiliation: Department of Cardiology, Chu of Brabois, Vandoeuvre, France.
authors.forename: B
authors.initials: B
authors.lastname: Brembilla-Perrot
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016279:Atrial Function, Left; D002648:Child; D004562:Electrocardiography; D004594:Electrophysiology; D006801:Humans; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology; D013617:Tachycardia, Supraventricular / Q000503:physiopathology*