title: Ibutilide increases the variability and complexity of atrial fibrillation electrograms: antiarrhythmic insights using signal analyses.
abstract: BACKGROUND
  Intravenous ibutilide is used to convert atrial fibrillation (AF) to sinus rhythm (SR) due to its Class III antiarrhythmic mechanisms. However, the effects of ibutilide on local electrograms (EGMs) during AF have not been elucidated.
  
  
  RESULTS
  We used EGM analysis techniques to characterize how ibutilide administration changes the frequency, morphology, and repeatability of AF EGM signals, thereby providing insight into ibutilide's antiarrhythmic mechanism of action. AF recordings were collected from 21 patients with AF, both before and after ibutilide administration. The effects of ibutilide on the following AF EGM parameters were assessed: (1) dominant frequency (DF), (2) variations in EGM amplitude and overall morphology, (3) repetition of EGM patterns, and (4) complexity of the AF frequency spectra. When comparing pre- versus post-ibutilide administration EGMs, DF decreased from 5.45 Hz to 4.02 Hz (P < 0.0001). There was an increase in the variability of both AF EGM amplitudes (P = 0.003) and overall AF EGM morphologies (P = 0.003). AF EGM pattern repetitiveness decreased (P = 0.01), and the AF frequency spectral profile manifested greater complexity (P = 0.02).
  
  
  CONCLUSIONS
  Novel EGM signal analysis techniques reveal that ibutilide administration causes increased complexity in the atrial electrical activation pattern with decreasing rate. These findings may be explained by the progressive destabilization of higher frequency, more homogeneous primary drivers of AF over the course of ibutilide administration, and/or less uniform propagation of atrial activation, until AF maintenance becomes more difficult and either transforms to atrial tachycardia or terminates to SR.
authors.affiliation: Cardiology Division, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York; Newyork-Presbyterian Hospital, Columbia University Medical Center, New York, New York.
authors.forename: Angelo B
authors.initials: AB
authors.lastname: Biviano
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Ciaccio
authors.forename: Tara
authors.initials: T
authors.lastname: Gabelman
authors.forename: William
authors.initials: W
authors.lastname: Whang
authors.forename: Hasan
authors.initials: H
authors.lastname: Garan
mesh_terms: D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013449:Sulfonamides / Q000008:administration & dosage*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000889:Anti-Arrhythmia Agents; D013449:Sulfonamides; C067192:ibutilide
keywords: atrial fibrillation; dominant frequency; electrogram analysis; ibutilide; linear prediction