title: Electrocardiographic markers of repolarization heterogeneity during dofetilide or sotalol initiation for paroxysmal atrial fibrillation.
abstract: Serial electrocardiographic monitoring of ΔQTc as an assumed harbinger of proarrhythmia is currently recommended for dofetilide and sotalol initiation. Markers of repolarization heterogeneity such as increased peak to end of T-wave (TpTe) duration and abnormal T-wave morphology may also predict proarrhythmia. We investigated whether such T-wave measurements on baseline electrocardiogram will correlate with ΔQTc after drug initiation. An analysis of 140 consecutive patients with paroxysmal atrial fibrillation hospitalized in sinus rhythm for sotalol or dofetilide initiation was performed. Baseline and serial electrocardiograms were analyzed using QT Guard Plus software (GE Healthcare), which measured QTc and TpTe and scored T-wave morphology for asymmetry, notching, and flatness using T-wave vector magnitude and principal component analysis algorithms. Sotalol and dofetilide were administered in 71% and 29% of patients, respectively. Mean age was 61 ± 14 years, and 34% were women. After a single dose of either drug, there was a statistically significant increase in QTc and TpTe (p <0.01), as well as composite and individual T-wave markers of repolarization heterogeneity (p <0.01). QTc increased by a mean of 19 ± 30 ms after initial antiarrhythmic dose. ΔQTc was inversely related to baseline QTc and TpTe (p <0.01). After controlling for baseline QTc, there was no independent association between T-wave markers of repolarization heterogeneity and ΔQTc. In conclusion, for patients with paroxysmal atrial fibrillation admitted for dofetilide or sotalol loading, T-wave markers of increased repolarization heterogeneity are measurable within hours after initiation. A shorter baseline QTc is associated with an increased ΔQTc; however, there is no independent relation between baseline T-wave markers of repolarization heterogeneity and ΔQTc.
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL. Electronic address: andrew-sauer@fsm.northwestern.edu.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sauer
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL.
authors.forename: Rachel
authors.initials: R
authors.lastname: Kaplan
authors.affiliation: GE Healthcare, Milwaukee, Wisconsin.
authors.forename: Joel
authors.initials: J
authors.lastname: Xue
authors.affiliation: GE Healthcare, Milwaukee, Wisconsin.
authors.forename: Patrick
authors.initials: P
authors.lastname: Dorsey
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL.
authors.forename: Matthew
authors.initials: M
authors.lastname: Hayes
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL.
authors.forename: Sanjiv J
authors.initials: SJ
authors.lastname: Shah
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL.
authors.forename: Rod
authors.initials: R
authors.lastname: Passman
mesh_terms: D000367:Age Factors; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy*; D015331:Cohort Studies; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004562:Electrocardiography / Q000187:drug effects* / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010627:Phenethylamines / Q000008:administration & dosage*; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D012984:Software; D013015:Sotalol / Q000008:administration & dosage*; D013449:Sulfonamides / Q000008:administration & dosage*; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D010627:Phenethylamines; D013449:Sulfonamides; D013015:Sotalol; C063533:dofetilide