On an electrocardiogram, the time between atrial and ventricular contraction is known as the:
a. P–R segment c. QRS interval
b. ST segment d. Q–T interval
ANS: A
The P–R segment represents the time delay that occurs within the atrioventricular node and therefore represents the time between atrial and ventricular contractions. The ST segment occurs during ventricular depolarization, the QRS interval represents ventricular polarization, and the Q–T interval represents the time required for ventricular depolarization and repolarization to oc-cur.
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