Elsevier

Journal of Electrocardiology

Volume 45, Issue 2, March–April 2012, Pages 178-184
Journal of Electrocardiology

Factors associated with development of prolonged QRS duration over 20 years in healthy young adults: the Coronary Artery Risk Development in Young Adults study

https://doi.org/10.1016/j.jelectrocard.2011.11.001Get rights and content

Abstract

Background

Data describing factors associated with the development of a prolonged QRS duration (QRSd) from young adulthood to middle age are sparse.

Methods

We analyzed 12-lead electrocardiograms (ECGs) from the Coronary Artery Risk Development in Young Adults study over 20 years. We performed logistic regression to examine the associations of baseline (year 0) or average (years 0-20) risk factors with incident prolonged QRSd (QRS >100 milliseconds).

Results

We included 2537 participants (57.2% women, 44.7% black; mean age, 25 years); 292 (11.5%) developed incident QRSd greater than 100 milliseconds by year 20. In univariate analyses, baseline covariates associated with incident QRSd prolongation included white race, male sex, ECG–left ventricular mass index, and baseline QRSd. Similar results were observed after multivariable adjustment.

Conclusion

We found no long-term associations of modifiable risk factors with incident QRSd >100 milliseconds. Men, whites, and those with higher ECG–left ventricular mass index and QRSd in young adulthood are at an increased risk for incident prolonged QRSd by middle age.

Introduction

The QRS complex on the standard, resting 12-lead electrocardiogram (ECG) is a manifestation of electrical impulse propagation through the conduction system and the ventricular myocardium. A QRS duration (QRSd) of 100 milliseconds or less has been considered “normal.”1 Although prolongation of the QRSd (typically >120 milliseconds) has been associated with adverse cardiovascular events including heart failure, sudden cardiac death, and mortality in older adults,2, 3, 4 intermediate degrees of QRSd (100-120 milliseconds) in younger, healthier populations also have been associated with an increased cardiovascular risk.5 Definitions of QRSd conferring risk have varied, and cutpoints of greater than 100 milliseconds, greater than 110 milliseconds, and greater than 120 milliseconds have all been associated with adverse cardiovascular disease events including heart failure.6, 7, 8, 9 Therefore, because QRSd appears to increase with age,6, 9 in healthier and younger populations, an intermediate QRSd may be appropriate to study and may confer cardiovascular risk.

Most studies examining QRSd have been limited by single time-point assessments of ECGs or limited longitudinal follow-up. Furthermore, factors associated with the development of a prolonged QRSd from young adulthood to middle age using serial ECGs and long-term traditional risk factor measurements have not been well described. Recognition of factors associated with the development of a prolonged QRSd may provide insight into the possible modifiers of this prognostically important ECG finding in middle age.

In the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, we hypothesized that participants with exposure to underlying cardiovascular risk factors such as hypertension and diabetes would be more likely to develop incident QRSd greater than 100 milliseconds. Therefore, we assessed longitudinal ECGs obtained during a 20-year period in a young, healthy, biracial population to determine prospective associations of established cardiovascular risk factors, subclinical atherosclerosis disease measures, and left ventricular (LV) structural measures by echocardiography with incident QRSd prolongation, defined a priori as QRSd greater than 100 milliseconds. Finally, we sought to determine whether there are sex and race differences in the development of incident QRSd greater than 100 milliseconds.

Section snippets

Study population

Details of the CARDIA study, enrollment and follow-up have been published elsewhere.10 Briefly, the CARDIA study began in 1985 to 1986 with the enrollment of 5115 black and white participants aged 18 to 30 years and balanced on sex, education status, and age distribution within a center. Participants were recruited in Birmingham, AL; Chicago, IL; Minneapolis, MN; and Oakland, CA. The institutional review board at each of the study sites approved the study protocols, and written informed consent

Study participants

There were 2537 participants included in the study sample who had no QRS greater than 100 at baseline (Y0) ECG examination, with 292 (11.5%) developing incident QRS greater than 100 milliseconds by Y20. Baseline characteristics are shown in Table 1, stratified by QRSd at Y20. White race, male sex, elevated serum creatinine, elevated systolic blood pressure, lower HDL cholesterol, higher BMI, and higher ECG-LVMI at Y0 were present in participants with incident QRSd greater than 100 milliseconds

Discussion

In this analysis of longitudinal risk factor associations with incident prolongation of the QRS complex among young adults from the CARDIA study, we observed 2 important findings. First, we observed a 11.5% incidence of QRSd greater than 100 milliseconds over 20 years in a young, healthy, biracial cohort. Moreover, we identify factors that are associated with the development of a prolonged QRSd in this population. Specifically, we found that white race, male sex, and baseline ECG-LVMI and

Conclusion

Because QRSd is an important prognostic marker in middle age, understanding factors that modify its progression and potentially preventing its development from young adulthood to middle age may have important implications. Despite long-term exposure to cardiovascular risk factors, we found no modifiable risk factor associations with incident QRSd greater than 100 milliseconds. Men, whites, and those with higher ECG-LVMI and QRSd in young adulthood appear to be at higher risk for development of

Acknowledgments

None.

Disclosures: LI: None; EZS: None; HN: None; KL: None; DML-J: None.

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    This work was supported (or partially supported) by R01 HL086792 and by the following contracts: University of Alabama at Birmingham, Coordinating Center, N01-HC-95095; University of Alabama at Birmingham, Field Center, N01-HC-48047; University of Minnesota, Field Center and Diet Reading Center (Year 20 Exam), N01-HC-48048; Northwestern University, Field Center, N01-HC-48049; and Kaiser Foundation Research Institute, N01-HC-48050, from the National Heart, Lung and Blood Institute.

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