Document Detail

The separate and joint effects of prolonged QT interval and heart rate on mortality.
MedLine Citation:
PMID:  19878945     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Understanding why prolonged Bazett-corrected QT interval (QTc) is a risk factor for mortality is difficult, because QTc is positively correlated with heart rate. To optimally distinguish the effects of QT interval and heart rate on mortality, QT interval and heart rate were modeled separately and jointly in Pima Indians. METHODS: The effects of QT and heart rate on all-cause and cause-specific mortality were assessed in the overall study population and according to the presence or absence of diabetes using multivariable time-dependent proportional hazards models. RESULTS: Among 1488 nondiabetic and 990 diabetic subjects > or =25 years old, 81 nondiabetic and 149 diabetic subjects died during a median follow-up of 7.3 years. When included in the same regression model, QT and heart rate each predicted all-cause mortality [hazard ratios per standard deviation (SD) (95% confidence interval)=1.31 (1.10-1.57) and 1.57 (1.32-1.87) respectively]. In nondiabetic subjects, hazard ratios for all-cause mortality were 1.54 (1.19-1.99) for QT and 1.86 (1.46-2.37) for heart rate. In diabetic subjects, hazard ratios for all-cause mortality were lower, 1.27 (1.00-1.62) for QT and 1.41 (1.12-1.78) for heart rate. In the overall study population, neither QT nor heart rate significantly predicted cardiovascular disease (CVD) mortality [hazard ratios=1.13 (0.77-1.64) and 1.46 (0.98-2.19)] when adjusted for each other. Heart rate unadjusted for QT, however, predicted CVD mortality [hazard ratio=1.34 (1.00-1.79)] in a separate model. CONCLUSIONS: QT prolongation and high heart rate both predict all-cause mortality in Pima Indians, but heart rate was consistently the stronger predictor of the two.
Nan Hee Kim; Meda E Pavkov; Robert G Nelson; Robert L Hanson; Peter H Bennett; Jeffrey M Curtis; Maurice L Sievers; William C Knowler
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural     Date:  2009-10-01
Journal Detail:
Title:  Atherosclerosis     Volume:  209     ISSN:  1879-1484     ISO Abbreviation:  Atherosclerosis     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-03-26     Completed Date:  2010-06-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0242543     Medline TA:  Atherosclerosis     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  539-44     Citation Subset:  IM    
Copyright Information:
Published by Elsevier Ireland Ltd.
Endocrinology and Metabolism, Korea University Medical School, Seoul, Republic of Korea.
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MeSH Terms
Arizona / epidemiology
Cause of Death
Diabetes Mellitus / mortality
Heart Rate / physiology*
Indians, North American*
Liver Diseases, Alcoholic / mortality
Long QT Syndrome / mortality*,  physiopathology
Middle Aged
Proportional Hazards Models
Risk Assessment

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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