Question

The patient's heart rhythm shows an inverted P wave with a PR interval of 0.06 seconds. The heart rate is 54 beats per minute. The nurse recognizes the rhythm as a junctional escape rhythm, and understands that the rhythm is due to the:

a. loss of sinus node activity.
b. increased rate of the AV node.
c. increased rate of the SA node.
d. decreased rate of the AV node.

Answer 1

The nurse recognizes the rhythm as a junctional escape rhythm, caused by the loss of sinus node activity. The AV node takes over as the heart's pacemaker, resulting in a slower rate of 40-60 beats per minute, which is observed in the patient's ECG.

Step-by-step explanation:

The patient's heart rhythm shows an inverted P wave with a PR interval of 0.06 seconds and a heart rate of 54 beats per minute, which the nurse correctly recognizes as a junctional escape rhythm. This type of rhythm is indicative of the loss of sinus node activity, leading the atrioventricular (AV) node to take over as the pacemaker of the heart. Normally, the sinoatrial node (SA node) establishes the sinus rhythm, but in cases where it fails, the AV node assumes this role, generating a heart rate lower than the SA node's usual pace of 80-100 beats per minute.

With the AV node pacing the heart, the rate generally drops to between 40-60 beats per minute, as the AV node has an inherent pacing rate slower than the SA node. In the event of a total SA block, which is a condition where the SA node ceases to transmit electrical impulses, the AV node compensates by maintaining this lower but adequate heart rate to ensure blood circulation.