Page 203 - Critical Care Nursing Demystified

188 CRITICAL CARE NURSING DeMYSTIFIED

• RATE: Atrial rate of between 60 and 100; ventricular rate of 30 to 40.
• RHYTHM: Regular in atrium and ventricles but they beat independently
of each other. The P does not cause the QRS as they are not communicat-
ing with each other.
• CONDUCTION: PRI varies from beat to beat. QRS are wide and bizarre
and may have P waves imbedded in them.

NURSING ALERT

Watch the ventricular response on this rhythm as too slow a heart rate can cause a
dramatic drop in BP, resulting from a decreased cardiac output. This can occur with
ischemia or MI. You need to prepare for temporary and/or permanent cardiac pacing
with this condition as most patients can not tolerate it for long.

Ventricular Rhythms

Along with the advanced heart blocks, ventricular rhythms must be identified and
follow-up care rendered. Rhythms can be one or two beats or sustained rhythms.
We will describe several of these bad actors, including premature ventricular con- 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.
tractions (PVCs), ventricular tachycardia (VT), ventricular fibrillation (VF), and
asystole. The last three rhythms are seen in a cardiac arrest or Code Blue.

Premature Ventricular Contractions (PVCs)
A premature ventricular contraction is an irritable beat that fires the ventricles
before the SA node can repolarize. The beat is early; the QRS is wide and
bizarre with a T wave often in the opposite direction of the QRS. Frequently a
pause after the PVC, called a compensatory pause, occurs because the heart
received a wallop of a stimulus too early and needs a longer time to recoup. This
sets the rhythm into an irregular pattern.
• RATE: Underlying rhythm could be anything.
• RHYTHM: Irregular at the PVC; it fires the ventricles early.
• CONDUCTION: PRI not present as no atrial conduction is associated
with a PVC. The QRS is wide and greater than 0.1 seconds, and it is very
different from the patient’s normally conducted QRS.
Patterns of PVCs PVCs can come in a regularly irregular fashion. There can be
• Bigeminy – 1 normal beat; 1 PVC
• Trigeminy – 2 normal beats; 1 PVC

• Quadrigeminy – 3 normal beats; 1 PVC