Question

Part 1: Would you say the atria or ventricle take longer to depolarize? Why?

A. Atria take longer to depolarize; the average length of the P wave is longer than the average length of the QRS complex

B. Ventricles take longer to depolarize; the average length of the P wave is longer than the average length of the QRS complex

C. Atria take longer to depolarize; the average length of the QRS complex is longer than the average length of the P wave

D. Ventricles take longer to depolarize; the average length of the QRS complex is longer than the average length of the P wave

Part 2: A physiologic explanation for the observed effect of age on pulse wave velocity would be the following:

PWV velocity is directly correlated with vascular stiffness. As one ages, the vessels progressively become “stiffer” due to things like arteriosclerosis/atherosclerosis which increases the velocity of the pulse wave.

TRUE OR FALSE?

Answer 1

1. ANSWER: D. Ventricles take more time to depolarize.the average length of the QRS complex is longer than that of the average length of P wave.

Reason: The ventricles are the last to depolarise and the first to repolarise. Also average duration of QRS complex is greater 0.10 and less than 0.12 seconds whereas duration of P wave is 0.10 seconds in maximum.

2. ANSWER: TRUE.

REASON: Pulse wave velocity is the marker of arterial stiffness. It is usually calculated by dividing distance with the pressure wave transit time at two points of recording arteries.