title: Ibutilide and novel indexes of ventricular repolarization in persistent atrial fibrillation patients.
abstract: OBJECTIVE
  To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF).
  
  
  METHODS
  We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1 + 1 mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion.
  
  
  RESULTS
  The final study population consisted of 20 patients (mean age: 67.1 ± 9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patients developed short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P = 0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P = 0.021), the Tpe interval in lead II from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P < 0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P = 0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P = 0.012). However, the Tpe/QT ratio in lead II did not change significantly.
  
  
  CONCLUSIONS
  Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.
authors.affiliation: Panagiotis Korantzopoulos, Anna Kotsia, Giannis Baltogiannis, Kallirroi Kalantzi, Konstantinos Kyrlas, John A Goudevenos, Department of Cardiology, University of Ioannina Medical School, 45110 Ioannina, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Korantzopoulos
authors.forename: Konstantinos P
authors.initials: KP
authors.lastname: Letsas
authors.forename: Anna
authors.initials: A
authors.lastname: Kotsia
authors.forename: Giannis
authors.initials: G
authors.lastname: Baltogiannis
authors.forename: Kallirroi
authors.initials: K
authors.lastname: Kalantzi
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kyrlas
authors.forename: John A
authors.initials: JA
authors.lastname: Goudevenos
keywords: Arrhythmic risk; Dispersion of repolarization; Ibutilide; Proarrhythmia; T peak-to-end; T peak-to-end/QT ratio; Ventricular repolarization