title: Induction of polymorphic ventricular tachycardia by programmed ventricular stimulation in vasospastic angina pectoris.
abstract: This study was designed to examine the ventricular vulnerability of patients with vasospastic angina. Fourteen patients (mean age 57 +/- 9 years) with vasospastic angina underwent electrophysiologic testing during the asymptomatic phase (baseline) and after the relief of acetylcholine-induced spasm with isosorbide dinitrates. Twenty patients without structural heart disease served as a control group. By programmed ventricular stimulation, polymorphic ventricular tachycardia (VT) was induced at baseline in 6 of 14 patients, with 1 patient developing ventricular fibrillation and 7 of 14 patients developing repetitive ventricular responses. After isosorbide dinitrate, polymorphic VT was induced in only 1 patient who had ventricular fibrillation at baseline. Repetitive ventricular responses were induced in 3 of 5 patients who had VT at baseline and in 4 of the 7 patients with repetitive ventricular responses at baseline. There was a significant difference in the incidences and severity of induced ventricular arrhythmias between the 2 phases (p <0.01). Among 20 control subjects, repetitive ventricular responses were induced only in 6 patients, but no VT was induced. There was a significant difference in the incidence of induced ventricular arrhythmias and VT at baseline between the vasospastic angina and control groups (p <0.001 and <0.01, respectively). Thus, patients with vasospastic angina had increased ventricular vulnerability, even during the symptom-free period without ischemic events, which could predispose to the development of life-threatening arrhythmias aggravated by vasospastic attacks.
authors.affiliation: Department of Cardiology, Yokohama Minami Kyosai Hospital, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nishizaki
authors.forename: M
authors.initials: M
authors.lastname: Arita
authors.forename: H
authors.initials: H
authors.lastname: Sakurada
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Ashikaga
authors.forename: N
authors.initials: N
authors.lastname: Yamawake
authors.forename: J
authors.initials: J
authors.lastname: Numano
authors.forename: M
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000328:Adult; D000368:Aged; D000788:Angina Pectoris, Variant / Q000150:complications / Q000503:physiopathology*; D003251:Constriction, Pathologic; D003331:Coronary Vessels / Q000473:pathology; D004558:Electric Stimulation; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000503:physiopathology*