Page 198 - Critical Care Nursing Demystified

Chapter 4 CARE OF THE PATIENT WITH CRITICAL CARDIAC RHY THM DISTURBANCE NEEDS 183

anxiety are some of the causes of tachycardias and need to be treated to reduce
the heart rate. Figure 4–6 was sinus tachycardia.
• RATE: Atrial/ventricular rate = greater than 100.
• RHYTHM: Atrial/ventricular rhythm = regular.

• CONDUCTION: All intervals are normal except the QTI may be short-
ened due to decreased diastolic filling time.

NURSING ALERT

An unexplained tachycardia should always be investigated; what is causing it and
why? Once determined, treat the underlying cause. If hypoxic, give oxygen; if feverish,
give antipyretics; if anxious, give sedatives. If you can not find the cause, notify the

health care provider.

Atrial Rhythms

In the rhythms covered previously, all of the pacemakers came from the SA
node; now you have a rhythm where the pacemaker changes. It is no longer in
the SA node; the pacemaker is in atrial tissue. Since the atrial pacemaker takes Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
over, you can see very distinct changes in the atrial heart rate and shape of the
P waves. Atrial rhythms we will explore include premature atrial contractions
(PACs), paroxysmal atrial tachycardia (PAT), atrial flutter, and atrial fibrillation.
Following are descriptions of what the nurse would analyze in each one.

Premature Atrial Contractions (PACs)
Premature atrial contractions, as their name suggests, are early contractions that
come from the atria. Because they come early from an irritable, cranky area of
the atrium, they cause the rhythm to fall out of synch. They can fall in any type
of underlying rhythm. You will see the following on a rhythm strip.
• RATE: The underlying rate can be anything from SB to NSR to ST. Some-
times the P wave will be upside down or different looking from the
patient’s SA node P waves. Since these do not come from the SA node,
they might look different than the native P waves.
• RHYTHM: The PAC throws the rhythm off because this beat is premature
or early.
• CONDUCTION: The other conduction intervals should be normal.
Occasionally, if the PAC originates close to the AV node, the PRI can be
shorter than normal.