What does a QRS duration greater than 0.10 seconds indicate?

• A. Wide QRS and abnormal ventricular conduction
• B. Normal conduction
• C. Short PR interval
• D. Absent P waves

Answer: (A)

QRS duration tracks how long ventricular depolarization takes. A normal QRS is about 0.10 seconds or less. When the QRS duration exceeds 0.10 seconds, ventricular activation is slowed or conducted through abnormal pathways, producing a wide QRS. This points to abnormal ventricular conduction, such as bundle branch blocks or other ventricular conduction delays. The other statements don’t fit because normal conduction would have a normal (short) QRS, the PR interval is a measure of atrioventricular conduction rather than ventricular depolarization, and absent P waves relate to atrial activity rather than how the ventricles depolarize.