7. Arrhythmia Interpretation, Arrhythmia emergencies, and Pacemaker Therapy

Question 1

Arrhythmia Interpretation, Arrhythmia emergencies, and Pacemaker Therapy

Answer 1

Test candidates are expected to have mastered arrhythmia interpretation and have an understanding of ACLS principles, so look these over. An exam question may describe the arrhythmia OR provide an arrhythmia strip for interpretation, but the question will usually be related to pt management.

Question 2

**For exam questions that include the development of an arrhythmia, pay close attention to the pt’s clinical response to the arrhythmia

Answer 2

** Is the pt stable or unstable? If the clinical description is NOT provided, consider this fact and do NOT assume the pt response!

Question 3

Conduction Abnormalities: Wolff-Parkinson-White syndrome

Answer 3

WPW is a genetic conduction abnormality in which an abnormal conduction pathway exists that allows a reentrant tachycardia pathway to bypass the normal AV node conduction pathway, resulting in supraventricular tachycardia. WPW is primarily seen in those younger than 30 years old.

Question 4

Wolff-Parkinson-White syndrome: When in sinus rhythm

Answer 4

the ECG demonstrates a short PR interval and the presence of a delta wave (seen as a slow rise in the initial upstroke of the QRS).

Question 5

WPW results in ___

Answer 5

SVT when the abnormal pathway takes over, but It may also present as PRE-EXCITED ATRIAL FIBRILLATION (irregular rhythm, rates of 150 beats/minute or greater, and a wide QRS.)

Question 6

Wolff-Parkinson-White syndrome: Signs and symptoms during SVT include

Answer 6

palpitations, dizziness, chest pain, sob, and syncope

Question 7

Treatment of Wolff-Parkinson-White syndrome

Answer 7

-Radiofrequency ablation to eliminate the reentrant pathway
-If unstable SVT is present, perform synchronized cardioversion OR administer adenosine
-If pre-excited atrial fibrillation (AF) is present, administer Bblockers, amiodarone, or procainadmide IV.
-Do NOT give adenosine, digoxin, or ca channel blockers for pre-excited AF; these agents may enhance antegrade conduction thru the abnormal pathway by increasing the refractory period in the AV node, RESULTING IN VENTRICULAR FIBRILLATION, VF.

Question 8

Conduction abnormalities: Prolongation of the QT interval

Answer 8

(causes, treatment) is often addressed on the CCRN exam. QT prolongation may lead to Torsades de pointes.

Question 9

**Causes of QT prolongation include

Answer 9

-Drugs–amiodarone, quinidine, haloperidol, procainamide.
-Electrolyte problems – hypokalemia, hypocalcemia, hypomagnesemia.

Question 10

**Treatment for Torsades VT

Answer 10

magnesium

Question 11

Pacemaker Therapy: Code

Answer 11

A = atria
V = Ventricle
D = dual (both)

Question 12

Pacemaker Code, paced v sensed

Answer 12

-First initial = chamber paced; this was “invented” first
-Second initial = chamber sensed; this function came
along second
-Third initial = response to sensing; last to be devd

Question 13

Third initial in pacer code

Answer 13

I = inhibits (pacer detects intrinsic cardiac activity and withholds its pacing stimuli)….demand
D = inhibits AND triggers (pacer detects intrinsic cardiac activity and fires a pacing stimuli in response)
O = none

Question 14

On the CCRN exam, you may see a Q that asks how a “VVI” or a “DDD” pacer works. If you remember the code, you should be able to figure out the answer.

Question 15

e.g. Which pacemaker paces both the atria and the ventricles, senses both the atria and the ventricles, and can inhibit and trigger in response to sensing?

Answer 15

DDD

Question 16

e.g. Which pacemaker paces the ventricle, senses the ventricle, and inhibits pacing in response to sensing?

Answer 16

VVI

Question 17

Review the 3 basic pacer malfunctions

Answer 17

1. failure to pace
2. failure to capture
3. failure to sense

Question 18

Failure to pace

Answer 18

No spike at all when expected

Question 19

failure to capture

Answer 19

spikes without a QRS for ventricular pacing, e.g.

Question 20

failure to sense

Answer 20

pacing in native beats

Question 21

Implantable Cardioverter-defibrillator (ICD)

Answer 21

ICDs can provide “tiered” therapy:
-programmed to SHOCK (defibrillate or synchronized cardioversion)
-Programmed to BURST PACE (sense tachyarrhythmia, provide a series of beats faster than the tachyarrhythmia, and then suddenly stop [with the hope of the recovery of the SA node]).
-Programmed to provide pacing for bradyarrhythmias

Question 22

If the ICD does not correct the sudden death arrhythmia,

Answer 22

shock as usual. DO NOT place shocking pads directly over the ICD.
Pt will require special education r/t device and emotional support, since many pts experience a FEAR of being shocked.