title: Distinct U wave changes in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT).
abstract: Although catecholaminergic polymorphic ventricular tachycardia (CPVT) is associated with fatal ventricular arrhythmias and sudden death, the ECG findings are not fully understood. In this paper, we report on alterations in the U-wave. Seven patients from 6 families with CPVT in which bidirectional tachycardia and polymorphic VT were induced by exercise or isoproterenol infusion visited our hospitals. VT was not inducible by programmed electrical stimulation. A novel gene mutation of the ryanodine receptor 2 (RyR2) was confirmed in 2 families. In one of these patients, U-wave alternans was observed following ventricular pacing at 160 beats/min. In the other patient, U-wave alternans was observed during the recovery phase after the exercise stress test, which was terminated because of polymorphic VT. In both cases, leads V3-V5 were the leads showing alternans most clearly. In the third patient, a negative U-wave became positive following a pause from sinus arrest and a change in T-wave was also noted. Since such findings were not found in the other subjects who underwent electrophysiologic study, isoproterenol infusion or exercise stress testing, the phenomenon seems to be relevant to the underlying pathogenesis of CPVT. The genesis and significance of U-wave alteration need to be determined.
authors.affiliation: Division of Cardiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Satoru
authors.initials: S
authors.lastname: Komura
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Okada
authors.forename: Masaomi
authors.initials: M
authors.lastname: Chinushi
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
authors.forename: Tohru
authors.initials: T
authors.lastname: Ohe
mesh_terms: D000293:Adolescent; D000328:Adult; D002395:Catecholamines; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D015444:Exercise; D005260:Female; D006801:Humans; D007545:Isoproterenol; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011110:Polymorphism, Genetic; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics; D017180:Tachycardia, Ventricular / Q000235:genetics* / Q000503:physiopathology*
chemical_list: D002395:Catecholamines; D019837:Ryanodine Receptor Calcium Release Channel; D007545:Isoproterenol