Pauses after burst pacing provoke afterdepolarizations and torsades de pointes in a patient with long QT syndrome.
A patient with long QT syndrome and syncope underwent electrophysiological testing and recording of monophasic action potentials (MAP). Programmed ventricular stimulation using up to three premature stimuli did not provoke arrhythmias. Transient action potential prolongation and afterdepolarizations were observed during pauses directly after high-rate fix frequent right ventricular burst pacing at 120-160 bpm. During the pause after burst pacing at 180 bpm, afterdepolarizations at 16-19% amplitude of the MAP plateau persisted for several beats and preceded a short episode of torsades de pointes. High-rate burst pacing provoked afterdepolarizations and triggered torsades de pointes in this patient with long QT syndrome.
Kirchhof
Paulus
P
Department of Cardiology and Angiology, University Hospital Münster, Germany. kirchhp@uni-muenster.de
Zellerhoff
Stephan
S
Mönnig
Gerold
G
Schulze-Bahr
Eric
E
D000200:Action Potentials / Q000502:physiology; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D001919:Bradycardia / Q000503:physiopathology / Q000517:prevention & control; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000503:physiopathology*; D010138:Pacemaker, Artificial; D016171:Torsades de Pointes / Q000209:etiology* / Q000503:physiopathology
D000319:Adrenergic beta-Antagonists