title: Short-term QT variability markers for the prediction of ventricular arrhythmias and sudden cardiac death: a systematic review.
abstract: Sudden cardiac death (SCD) is a major health burden and is primarily caused by ventricular arrhythmias. Currently, the most well-known marker for the risk of ventricular arrhythmias is QT/QTc prolongation. Animal studies indicate that QT variability might be a better indicator. Our objective was to give an overview of the literature on QT variability in humans, therefore we performed a free-text search in PubMed and Embase from inception through February 2013. We identified nine QT variability markers in 109 studies reporting on QT variability markers, measured on the surface ECG. QT variability can be distinguished using two characteristics: heart rate normalisation and whether QT interval is measured on consecutive beats. Most study populations were small (median 48 subjects, range 1-805) and different methods, time intervals and leads for measurement were used. QT variability markers were determinants for the risk of ventricular arrhythmias, (sudden) cardiac death and total mortality. Few studies compared the predictive value of QT variability with that of QT/QTc prolongation. A study comparing all different QT variability markers is lacking. In conclusion, QT variability markers are potential determinants of ventricular arrhythmias and cardiac mortality. However, it is unclear which marker and methodology are clinically most useful as well as what reference values are reliable. More studies on larger datasets are needed to find the most accurate marker for the prediction of arrhythmias and SCD to assess its value in addition to QT/QTc duration and its role in drug-induced arrhythmia and sudden death.
authors.affiliation: Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Maartje N
authors.initials: MN
authors.lastname: Niemeijer
authors.affiliation: Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Marten E
authors.initials: ME
authors.lastname: van den Berg
authors.affiliation: Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Eijgelsheim
authors.affiliation: Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Gerard
authors.initials: G
authors.lastname: van Herpen
authors.affiliation: Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands Inspectorate of Health Care, The Hague, The Netherlands.
authors.forename: Bruno H
authors.initials: BH
authors.lastname: Stricker
authors.affiliation: Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Kors
authors.affiliation: Department of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Rijnbeek
mesh_terms: D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004562:Electrocardiography; D006339:Heart Rate; D006801:Humans; D011237:Predictive Value of Tests; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors
keywords: Arrhythmias