The time it takes for peak voltage to develop within the ventricles, measured from the onset of the QRS to the peak of the R wave, is the ________ deflection. A prolonged version (>0.06 s) is considered a late R wave.

The time it takes for peak voltage to develop within the ventricles, measured from the onset of the QRS to the peak of the R wave, is the ________ deflection. A prolonged version (>0.06 s) is considered a late R wave.

• A. Intrinsicoid deflection
• B. QRS duration
• C. PR interval
• D. ST segment

Answer: (A)

Intrinsicoid deflection is the R wave peak time—the interval from the onset of the QRS complex to the peak of the R wave. This measures how quickly the ventricles, especially the left ventricle, are being activated. A prolonged intrinsicoid deflection (often considered around 60 ms or more) is described as a late R wave, which can indicate delayed left ventricular conduction or hypertrophy.

This differs from the total QRS duration, which covers the entire ventricular depolarization time; the PR interval, which reflects atrioventricular conduction; and the ST segment, which lies after depolarization and before repolarization.