UMEM Educational Pearls

Category: Cardiology

Title: normal QRS intervals

Keywords: electrocardiography, QRS, intervals (PubMed Search)

Posted: 5/3/2010 by Amal Mattu, MD
Click here to contact Amal Mattu, MD

Slight revisions have been made in what is considered to be normal QRS duration.
In children < 4yo, a normal QRS duration is < 90ms.
In children 4-16yo, a normal QRS duration is < 100ms.
Above the age of 16, a normal QRS duration is < 110m.

Consider these numbers when evaluating patients for aberrant conduction (e.g. toxicologic reasons as well) and when defining conduction blocks.

Surawicz B, Childers R, Deal BJ, et al. AHA/ACCF/HRS Recommendations for the standardized interpretation of the electrocardiogram, Part III: Intraventricular conduction disturbances. A scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. J Am Coll Cardiol 2009;53(11):976-981.