Published Online
on January 26, 2009

A more recent version of this article appeared on February 10, 2009

This Article Full Text (PDF) CME: Take the course for this article: Circulation: February 10, 2009, Volume 119, Number 5 All Versions of this Article: 119/5/663    most recent CIRCULATIONAHA.108.797035v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chugh, S. S. Articles by Jui, J. Search for Related Content PubMed PubMed Citation Articles by Chugh, S. S. Articles by Jui, J. Pubmed/NCBI databases Medline Plus Health Information Cardiac Arrest Coronary Artery Disease Related Collections Arrhythmias, clinical electrophysiology, drugs Epidemiology Related Article

Submitted on June 9, 2008
Accepted on November 24, 2008

Determinants of Prolonged QT Interval and Their Contribution to Sudden Death Risk in Coronary Artery Disease. The Oregon Sudden Unexpected Death Study

Sumeet S. Chugh MD^*, Kyndaron Reinier PhD, Tejwant Singh MD, Audrey Uy-Evanado MD, Carmen Socoteanu MD, Dawn Peters PhD, Ronald Mariani EMT-P, Karen Gunson MD, and Jonathan Jui MD, MPH

From the Cardiac Arrhythmia Center, Division of Cardiovascular Medicine, Oregon Health and Science University, Portland.

^* To whom correspondence should be addressed. E-mail: sumeet.chugh{at}cshs.org.

Background—In a recent cohort study, prolongation of the corrected QT interval (QTc) was associated with an independent increased risk of sudden cardiac death (SCD). We evaluated determinants of prolonged QTc and the relationship of prolonged QTc to SCD risk among patients with coronary artery disease in the general population.

Methods and Results—A case-control design was used. Cases were SCD patients with coronary artery disease among a metropolitan area of 1 000 000 residents (2002 to 2006); controls were area residents with coronary artery disease but no history of SCD. All cases were required to have an ECG suitable for QTc analysis before and unrelated to the occurrence of SCD. A total of 373 cases and 309 controls met criteria for analysis. Mean QTc was significantly longer in cases than in controls (450±45 versus 433±37 ms; P<0.0001). In a multivariate model, gender, diabetes mellitus, and QTc-prolonging drugs were significant determinants of QTc prolongation in controls. In a logistic regression model predicting SCD, diabetes mellitus (odds ratio, 1.97; 95% confidence interval, 1.32 to 2.96) and use of QTc-prolonging drugs (odds ratio, 2.90; 95% confidence interval, 1.92 to 4.37) were significant predictors of SCD among subjects with normal or borderline QTc. However, abnormally prolonged QTc in the absence of diabetes and QT-prolonging medications was the strongest predictor of SCD (odds ratio, 5.53; 95% confidence interval, 3.20 to 9.57).

Conclusions—Diabetes mellitus and QTc-affecting drugs determined QTc prolongation and were predictors of SCD in coronary artery disease. However, idiopathic abnormal QTc prolongation was associated with 5-fold increased odds of SCD. A continued search for novel determinants of QTc prolongation such as genomic factors is likely to enhance risk stratification for SCD in coronary artery disease.

Key words: coronary disease • death, sudden • epidemiology • population • diabetes mellitus • prescription drugs • risk

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