Rhythm Interpretation第 2 / 100 题
What is the normal duration of the QRS complex in an adult?
a.Less than 0.12 second
b.0.12 to 0.20 second
c.0.20 to 0.36 second
d.Greater than 0.44 second
解析
A normal QRS is under 0.12 second (fewer than three small boxes) because the ventricles depolarize rapidly through the bundle branches and Purkinje fibers. The 0.12 to 0.20 second range describes the PR interval, not the QRS. Values of 0.20 second or more suggest a bundle branch block or a beat that started in the ventricles, and 0.44 second is a QT-interval reference, not a QRS value.
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