ArticleAnnals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc2020
Clinically significant incidental QTc prolongation is subject to within-individual variability.
Article in Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
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Who cites it
12 citing papers in PubMed.
- Methadone administration and QT interval prolongation: protocol for a systematic review and meta-analysis.BMJ open · 2026Article
- Dilemma of Finding the Most Useful QTc Formula: A Retrospective Analysis of South-East London.Cureus · 2025Article
- Surveillance of Corrected QT Interval-Prolonging Medications upon Admission throughout Hospitalization in a Tertiary Care Geriatric Ward.Medical principles and practice : international journal of the Kuwait University, Health Science Centre · 2025Article
- Automated Quantification of QT-Intervals by an Algorithm: A Validation Study in Patients with Chronic Obstructive Pulmonary Disease.International journal of chronic obstructive pulmonary disease · 2024Article
- The Heart of Rett Syndrome: A Quantitative Analysis of Cardiac Repolarization.Cardiology research · 2023Article
- Development and Validation of a Nomogram for Prediction of QT Interval Prolongation in Patients Administered Bedaquiline-Containing Regimens in China: a Modeling Study.Antimicrobial agents and chemotherapy · 2022Article
- QTc interval on 24-hour holter monitor: To trust or not to trust?Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc · 2022Article
- Influence of heart rate correction formulas on QTc interval stability.Scientific reports · 2021Article
- Problems with Bazett QTc correction in paediatric screening of prolonged QTc interval.BMC pediatrics · 2020Article
- Clinically significant incidental QTc prolongation is subject to within-individual variability.Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc · 2020Article
- Sources of QTc variability: Implications for effective ECG monitoring in clinical practice.Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc · 2020Review
- Validation of a Clinical Decision Support Tool for Quantifying Risk of Torsades de Pointes in a Psychiatric Inpatient Population.Innovations in clinical neuroscienceArticle
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Authors and funding
8 authors.
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No grant is acknowledged in the PubMed record.
Abstract
backgroundProlonged QTc interval observed in daily practice is often deemed to be drug induced and might result in drug discontinuation, with possible therapeutic consequences. However, whether clinically significant prolonged QTc may be due to within-individual variability occurs has yet to be described.
methodsA retrospective cohort study documenting within-individual QTc variability in subjects attending annual routine medical evaluation. At each visit, QT interval was measured and corrected for heart rate using Bazett and three other commonly used formulae. Outcome measures were rates of ΔQTc ≥60 msec, absolute QTc ≥500 msec and QTc ≥25% from baseline.
resultsA total of 188 subjects [54 (29%)] females were recruited. Mean age at first ECG was 54 ± 12.8 years with mean time interval of 12.2 ± 1.1 months between measurements. Mean Bazett QTc was higher compared to the other 3 formulae: 412 ± 20 vs. 400 ± 16 msec. Using Bazett formula, 18/188 (9.6%) and 5/188 (2.7%) subjects showed at least one measurement with ΔQTc ≥60 msec and QTc ≥500 msec, respectively. Of the former, 5/18 (27.8%) showed QTc ≥25% prolongation. In multivariate analysis, QTc ≥500 msec was significantly associated with number of measurements (HR: 5.01, 95%CI: 1.21-20.78, p = .026) with no effect of other known confounders. Lower rates were demonstrated with the other three formulae.
conclusionIn clinical practice, significant prolonged QTc may be attributed to within-individual variability, particularly when adjusting the QT interval with Bazett correction. This should be taken into consideration when decisions on changing current drug regimens are to be made.
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