Consistency of heart rate-QTc prolongation consistency and sudden cardiac death: The Rotterdam Study

Maartje N Niemeijer; Marten E van den Berg; Jaap W Deckers; Oscar H Franco; Albert Hofman; Jan A Kors; Bruno H Stricker; Peter R Rijnbeek; Mark Eijgelsheim

doi:10.1016/j.hrthm.2015.07.011

Consistency of heart rate-QTc prolongation consistency and sudden cardiac death: The Rotterdam Study

Heart Rhythm. 2015 Oct;12(10):2078-85. doi: 10.1016/j.hrthm.2015.07.011. Epub 2015 Jul 9.

Authors

Maartje N Niemeijer¹, Marten E van den Berg², Jaap W Deckers³, Oscar H Franco¹, Albert Hofman¹, Jan A Kors², Bruno H Stricker⁴, Peter R Rijnbeek², Mark Eijgelsheim⁵

Affiliations

¹ Department of Epidemiology.
² Department of Medical Informatics.
³ Department of Cardiology.
⁴ Department of Epidemiology; Department of Internal Medicine, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands; Inspectorate of Health Care, Utrecht, The Netherlands. Electronic address: b.stricker@erasmusmc.nl.
⁵ Department of Epidemiology; Department of Internal Medicine, Erasmus MC - University Medical Center Rotterdam, Rotterdam, The Netherlands.

PMID: 26165945
DOI: 10.1016/j.hrthm.2015.07.011

Abstract

Background: A prolonged heart rate-corrected QT (QTc) interval is a well-known risk indicator for sudden cardiac death (SCD) and a contraindication for drugs with potentially arrhythmogenic adverse effects.

Objective: We aimed to study the consistency of QTc interval prolongation and whether a consistent QTc interval prolongation correlates differently with SCD than does an inconsistently prolonged QTc interval.

Methods: We used a population-based cohort study of persons 55 years and older. We excluded participants using QTc-prolonging drugs or with bundle branch block. The QT interval was corrected for heart rate using Bazett and Fridericia formulas. Using a Cox regression model, we assessed the association between QTc interval prolongation consistency and the occurrence of SCD.

Results: A total of 3484 participants had electrocardiograms (ECGs) recorded on 2 consecutive visits. In 96%-98% of participants with a normal QTc interval on the first ECG, the QTc interval remained normal, but only in 27%-35% of those with a prolonged QTc interval, the QTc interval was prolonged on the second ECG after a median of 1.8 years. A consistently prolonged QTc interval was associated with an increased risk of SCD as compared with a consistently normal QTc interval (Bazett: hazard ratio 2.23; 95% confidence interval 1.17-4.24, Fridericia: hazard ratio 6.67; 95% confidence interval 2.96-15.06). A prolonged QTc interval preceded or followed by a normal QTc interval was not significantly associated with an increased risk of SCD.

Conclusion: Persons with an inconsistently prolonged QTc interval did not have a higher risk of SCD than those with a consistently normal QTc interval. Persons with a consistently prolonged QTc interval did have a higher risk of SCD. Our results suggest that repeated measurements of the QTc interval could enhance risk stratification.

Keywords: Electrocardiogram; Epidemiology; Population-based; QT interval; Sudden cardiac death.

MeSH terms

Aged
Death, Sudden, Cardiac / epidemiology*
Death, Sudden, Cardiac / etiology
Electrocardiography*
Female
Follow-Up Studies
Heart Rate / physiology
Humans
Long QT Syndrome / complications
Long QT Syndrome / mortality
Long QT Syndrome / physiopathology*
Male
Middle Aged
Netherlands / epidemiology
Population Surveillance / methods*
Prognosis
Proportional Hazards Models
Retrospective Studies
Risk Factors
Survival Rate