title: Intraventricular concealed double tachycardia: a case report.
abstract: An electrophysiologic study was performed on a patient with ischemic sustained ventricular tachycardia (VT). During pacing at the right ventricular apex, ventricular double potential was recorded at the left ventricular apex. Sustained VT was induced by double extra stimuli from the right ventricular apex. Three types of VTs with different QRS morphologies were observed, and each VT was changeable to other types. The interval between one of the two potentials and the surface QRS was constant during all VTs, but the other potential showed dissociation from the surface QRS. During this dissociation, an intrinsic rhythm of the potential was sometimes shorter than the cycle length of the VT. The mechanism of a block between the VT and a bystander could hardly explain these electrophysiologic findings. Concealed double ventricular tachycardia was considered to be the likely mechanism.
authors.affiliation: First Department of Internal Medicine, Niigata University School of Medicine, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Niwano
authors.forename: Y
authors.initials: Y
authors.lastname: Aizawa
authors.forename: M
authors.initials: M
authors.lastname: Tamura
authors.forename: A
authors.initials: A
authors.lastname: Shibata
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D003327:Coronary Disease / Q000503:physiopathology; D004558:Electric Stimulation; D004562:Electrocardiography; D004594:Electrophysiology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D013610:Tachycardia / Q000175:diagnosis* / Q000503:physiopathology