Pacemakers

Question 0

What are the 3 components of a Pacemaker, used to produce a repetitive electrical stimulus and convey it directly to the myocardium

Answer 0

1) Power Source - Battery unit called a pulse generator.
2) Conducting Wire - Electrode that goes to the heart to provide the stimulus.
3) Return Wire - Wire that runs to the battery unit to complete the electrical circuit.

Question 1

Define Capture

Answer 1

Capture - Pacemaker-induced depolarization of the heart.

Question 2

Describe the two basic ways in which Pacemakers can initiate impulses.

Answer 2

1) Triggered - Fixed-rate pacemakers that fire according to a predetermined plan, regardless of the patients underlying cardiac activity.
2) Inhibited - Pacemakers that only fire when needed.

Question 3

Describe the 3 letter classification system of Pacemakers.

* Remember “PSR”

Answer 3

1) Chamber Paced - Ventricle (V), Atrium (A), or Both (D-dual).
2) Chamber Sensed - Ventricle (V), Atrium (A), Both (D-dual), Neither (O).
3) Pacemaker Response - Triggered (T), Inhibited (I), Dual (D).

Question 4

Explain how a Pacemaker Response can be classified as “dual”.

Answer 4

It is triggered by the Atria and and inhibited by the Ventricles.

Question 5

Describe the Pacemaker setting of Override/Overdrive.

Answer 5

Override/Overdrive is used for tacchycarrhythmias. The rate is set faster than the patient’s own rate, which leads to the pacemaker becoming the dominant pacemaker. Then the pacemaker rate is turned down to control the rate.

Question 6

What are the 2 mentioned indications for VVI pacemaker?

Answer 6

1) AV Blocks

2) Atrial Arrhythmias (especially AFib)

Question 7

What are the 2 mentioned indications for DDI pacemakers?

Answer 7

1) Combination of AV Block and SSS

2) LV dysfunction in patients who need coordination of Atrial and Ventricular contractions to maintain adequate output.

Question 8

What are the 2 main indications for Permanently Implanted Biventricular Pacemakers?

Answer 8

1) HOCUM

2) CHF

Question 9

What are the 5 main SxS of Symptomatic Bradycardia?

Answer 9

1) Syncope
2) SOB
3) Chest Pain
4) Dizziness
5) Lightheadedness & Loss of consciousness

Question 10

What is the ACLS Tx for Bradycardia?

Answer 10

• All Trained Dogs Eat Iams
  1) Atropine IV (0.5 mg, repeat Q5mins for a total of 3.0 mg).
  2) Transcutaneous Pacing (TCP)
  3) Dopamine drip
  4) Epinephrine drip
  5) Isuprel drip (not used)

Question 11

What are the 4 main reasons Pacemakers fail to capture?

Answer 11

1) Threshold rise
2) Lead dislodgment
3) Lead fracture
4) RV infarct

Question 12

What does “Failure to Capture” look like on the monitor?

Answer 12

Pacer spikes are present but no ECG response

Question 13

Which interventions are used when a Pacemaker fails to capture?

Answer 13

1) ⬆ mA (called output on pacer)
2) Change polarity of lead wires
3) Reposition patient on side in case the lead has been dislodged
4) Assess for dislodged wires
5) CPR/ACLS
6) Transcutaneous Pacing

Question 14

Which occupations may need to be changed in a patient with a new pacemaker and why?

Answer 14

Occupations such as car mechanics and high wire repairmen electromagnetic fields disrupt the functioning of pacemakers.

Question 15

What is the significance of hiccups or muscle spasms at the set heart rate in a patient with a pacemaker?

Answer 15

The electrodes might have perforated the muscle wall and is pacing the diaphragm.

Question 16

What are the important teaching points for a patient with a new Pacemaker?

Answer 16

1) Don’t handle sores with bare hands (use gloves).
2) No lifting weights > 5-10 lbs for 6 weeks
3) Do not lift elbow above shoulders for 6 weeks
4) Carry pacemaker card at all times
5) How to take own pulse each day

Question 17

What does a Right Bundle Branch Block (RBBB) look like on an ECG and why?

Answer 17

Looks like rabbit ears with an R’ in lead V1, because the right fascicles is blocked, so the impulse travels through the cardiac cells instead of the electrical cells, therefore taking longer (6x longer) and resulting in a wide ( > 0.12 secs) QRS.

Question 18

RBBBs are very common in patients with which 3 disorders?

Answer 18

1) HTN
2) CAD
3) Hx of MI

Question 19

What does a LBBB look like on an ECG?

Answer 19

Looks like a normal cardiac cycle except the widened QRS (normal Pwave and PRI present).