Brief Article
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World J Cardiol. Jul 26, 2013; 5(7): 242-246
Published online Jul 26, 2013. doi: 10.4330/wjc.v5.i7.242
Ibutilide and novel indexes of ventricular repolarization in persistent atrial fibrillation patients
Panagiotis Korantzopoulos, Konstantinos P Letsas, Anna Kotsia, Giannis Baltogiannis, Kallirroi Kalantzi, Konstantinos Kyrlas, John A Goudevenos
Panagiotis Korantzopoulos, Anna Kotsia, Giannis Baltogiannis, Kallirroi Kalantzi, Konstantinos Kyrlas, John A Goudevenos, Department of Cardiology, University of Ioannina Medical School, 45110 Ioannina, Greece
Konstantinos P Letsas, Second Department of Cardiology, Evangelismos General Hospital of Athens, 10675 Athens, Greece
Author contributions: Korantzopoulos P, Letsas K and Goudevenos JA contributed to the conception and design of the study, drafting the article, final approval; Kotsia A, Baltogiannis G, Kalantzi K and Kyrlas K contributed to the acquisition of data, critical revision of the article, final approval.
Correspondence to: Panagiotis Korantzopoulos, MD, PhD, Department of Cardiology, University of Ioannina Medical School, Campus, PO Box 1186, 45110 Ioannina, Greece. p.korantzopoulos@yahoo.gr
Telephone: +30-26-51045654 Fax: +30-26-51007017
Received: February 10, 2013
Revised: May 15, 2013
Accepted: June 1, 2013
Published online: July 26, 2013
Processing time: 173 Days and 11.5 Hours
Abstract

AIM: 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.

CONCLUSION: 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.

Keywords: Ibutilide, Ventricular repolarization, Arrhythmic risk, Proarrhythmia, Dispersion of repolarization, T peak-to-end, T peak-to-end/QT ratio

Core tip: In this pilot study we examined the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation scheduled for electrical cardioversion. Electrocardiographic (ECG) indexes such as corrected QT interval, the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured. We showed that ibutilide significantly increases the dispersion of ventricular repolarization as assessed by modern ECG markers such as Tpe interval and Tpe/QT ratio. These indexes may have a prognostic value with regard to drug-induced proarrhythmia.