Document Detail

Irregular Ventricular Activation Results in QT Prolongation and Increased QT Dispersion: A New Insight Into the Mechanism of AF-Induced Ventricular Arrhythmogenesis.
MedLine Citation:
PMID:  21668564     Owner:  NLM     Status:  Publisher    
Effects of Irregular Pacing on Repolarization. Introduction: Atrial fibrillation (AF) has been shown to be associated with increased risk of ventricular arrhythmias. We have previously shown reverse electrical remodeling of the ventricles following successful restoration of sinus rhythm in patients with persistent AF. The purpose of this study was to assess the relative role of irregular ventricular activation in mediating the previously observed changes. Methods and Results: Twenty-two patients referred for an invasive electrophysiologic study were randomized to 30 minutes of regular or irregular atrioventricular (AV) sequential pacing at 100 beats per minute (bpm) with a programmed AV interval of 100 ms. Irregular pacing was triggered from prerecorded digital signal with a mean rate of 100 bpm, and a standard deviation of 150 ms (25% of the mean rate). In the regular pacing group, QT and QTc decreased from 448 ± 102 ms and 453 ± 105 ms to 428 ± 109 ms and 442 ± 104 ms, respectively (P < 0.001 for QT interval and P < 0.001 for QTc interval). There was no significant change in QT dispersion. In the irregular pacing group, QT and QTc increased from 477 ± 104 ms and 486 ± 78 ms to 489 ± 106 ms and 500 ± 106 ms (P < 0.01 for QT interval and P = 0.03 for QTc interval). In addition, there was a significant increase in QT dispersion from 50 ± 22 ms to 66 ± 22 ms (P = 0.001). Since the rate and pacing sites were similar between the groups, we attribute the repolarization changes in the irregular pacing group to the irregular activation of the ventricles. Conclusion: The detrimental effects of irregular pacing go beyond the hemodynamic changes and include electrical remodeling that favors an arrhythmogenic substrate. (J Cardiovasc Electrophysiol, Vol. pp. 1-4).
Nazem W Akoum; Natalie A Sanders; Stephen L Wasmund; Mohamed H Hamdan
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-6-10
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  -     ISSN:  1540-8167     ISO Abbreviation:  -     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-6-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2011 Wiley Periodicals, Inc.
University of Utah, Medical Center, Salt Lake City, Utah, USA.
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