Importance of QRS Duration in Patients with Suspected Coronary Artery Disease

Abstract & Commentary

By Harold L. Karpman, MD, FACC, FACP, Clinical Professor of Medicine, UCLA School of Medicine. Dr. Karpman reports no financial relationship to this field of study.

Synopsis: Resting QRS duration is an independent predictor of cardiac death and/or myocardial infarction in patients with suspected CAD.

Source: Arend FL, et al. Prognostic significance of QRS duration in patients with suspected coronary artery disease referred for noninvasive evaluation of myocardial ischemia. Am J Cardiol 2009;104:1490-1493.

The standard 12-lead electrocardiogram is an important first test for cardiac risk stratification because of its simplicity and wide availability. Several published studies in patients with previous myocardial infarctions and/or congestive heart failure have demonstrated that the QRS duration correlated strongly with the eventual clinical outcome.1-3

Because the prognostic impact of prolonged QRS duration in patients without known structural heart disease had not yet been evaluated, Arend and his colleagues mounted a study to evaluate the prognostic significance of the QRS duration in patients with suspected coronary artery disease (CAD) referred for non-invasive evaluation of myocardial ischemia by dobutamine stress echocardiography. During the mean follow-up period of 4.2 years, 280 patients died and 60 suffered a nonfatal myocardial infarction among the 1227 patients who were studied. Annualized event rates for cardiac death and/or myocardial infarction were significantly greater in patients who demonstrated QRS durations equal to or greater then 120 msec. QRS duration on the standard resting electrocardiogram therefore appears to be an independent predictor of cardiac death and cardiac death/nonfatal infarction in patients with suspected CAD.

Commentary

Prior studies have clearly demonstrated that the QRS duration in patients with suspected CAD (i.e., left ventricular dysfunction, heart failure, recurrent ventricular arrhythmias) provides incremental prognostic information regarding clinical outcomes.1-3 The Arend study revealed that the QRS duration in patients with suspected (and not yet proven) CAD also provides incremental prognostic information not only for the prediction of cardiac death, but also for the combined endpoints of cardiac death and/or myocardial infarction. Therefore, this simple, inexpensive and objective measurement can be used as an add-on to myocardial stress testing for risk stratification of patients with suspected and not already proven CAD. Although this study utilized a single, very specific type of provocative stress test, the findings suggest that careful measurements of the resting QRS duration is almost certainly of value in all patients and that the information derived will help clinicians determine CAD prognosis in the individual patient with or without known CAD. However, larger, carefully controlled and longer trials in these patients are needed to properly position the information derived by measuring QRS complex width into our prognostic armamentarium.

References

1. Silvet H, et al. Prognostic implications of increased QRS duration inpatients with moderate and severe left ventricular dysfunction. Am J Cardiol 2001;88:182-185.

2. Yamada T, et al. Usefulness of spatial dispersion of QRS duration in predicting mortality in patients with mild to moderate heart failure. Am J Cardiol 2004;94: 960-963.

3. Guttigoli AB, et al. Usefulness of prolonged QRS duration to identify high-risk ischemic cardiomyopathy patients with syncope and inducible ventricular tachycardia. Am J Cardiol 2005;95:391-394.