title: Electrophysiological mechanisms of long and short QT syndromes.
abstract: The QT interval on the human electrocardiogram is normally in the order of 450 ms, and reflects the summated durations of action potential (AP) depolarization and repolarization of ventricular myocytes. Both prolongation and shortening in the QT interval have been associated with ventricular tachy-arrhythmias, which predispose affected individuals to sudden cardiac death. In this article, the molecular determinants of the AP duration and the causes of long and short QT syndromes (LQTS and SQTS) are explored. This is followed by a review of the recent advances on their arrhythmogenic mechanisms involving reentry and/or triggered activity based on experiments conducted in mouse models. Established and novel clinical risk markers based on the QT interval for the prediction of arrhythmic risk and cardiovascular mortality are presented here. It is concluded by a discussion on strategies for the future rational design of anti-arrhythmic agents.
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, PR China.
authors.forename: Gary
authors.initials: G
authors.lastname: Tse
authors.affiliation: Department of Psychology, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Yin Wah Fiona
authors.initials: YW
authors.lastname: Chan
authors.affiliation: Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, SAR, PR China.
authors.forename: Wendy
authors.initials: W
authors.lastname: Keung
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, PR China; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Yan
keywords: Cardiac arrhythmia; Long QT syndrome; Repolarization; Short QT syndrome; Wavelength