Which QRS duration is considered normal?

• A. 0.12 seconds
• B. 0.10 seconds
• C. 0.15 seconds
• D. 0.08 seconds

Answer: (D)

QRS duration reflects the time it takes for the ventricles to depolarize. In a healthy heart, this happens quickly, producing a narrow QRS complex. Clinically, a normal QRS duration is about a tenth of a second or less; when it lengthens beyond that, it suggests a conduction delay such as a bundle-branch block. Among the given values, the one that clearly stays within this normal window is the shorter duration. The other options approach or exceed the upper limit of what’s considered normal, indicating prolonged ventricular conduction. So the value that best represents normal ventricular conduction is the shorter one.