1. Pacemaker for beginners
HAZHIR HEIDARI BEIGVAND

2. Objectives Review basic pacemaker terminology and function
Discuss diagnosis and management of pacemaker emergencies

3. Historical Perspective
Electrical cardiac pacing for the management of brady-arrhythmias was first described in 1952
Permanent transvenous pacing devices were first introduced in the early 1960’s

4. Pacemaker Components
Pulse Generator
Electronic Circuitry
Lead system

5. Pulse Generator Lithium-iodine cell is the current standard battery
Advantages:
Long life – 4 to 10 years
Output voltage decreases gradually with time making sudden battery failure unlikely

6. Electronic Circuitry Determines the function of the pacemaker itself
Utilizes a standard nomenclature for describing pacemakers

7. Pacemaker NomenclatureI II
III IV V
Chamber Paced
Chamber Sensed
Response to Sensing
Rate Modulation, Programmability
Anti-tachycardia Features
A=Atrium
T=Triggered
P=Simple
P=Pacing
V=Ventricle
I=Inhibited
M=Multi-programmable
S=Shock
D=Dual
R=Rate Adaptive
O=None
C=Communicating

8. Lead Systems
Endocardial leads which are inserted using a subclavian vein approach
Actively fixed to the endocardium using screws or tines
Unipolar or bipolar leads
Unipolar lead is smaller, more flexible, less likely to fracture but not compatible with ICD

11. Electrocardiogram During Cardiac Pacing
Pacemaker has two main functions:
Sense intrinsic cardiac electrical activity
Electrically stimulate the heart
VVI- senses intrinsic cardiac activity in the ventricle and when a preset interval of time with no ventricular activity occurs it depolarizes the right ventricle causing ventricular contraction

12. Pacer spike

13. Electrocardiogram
Dual chamber pacer is more complicated because the pacer has the ability to both sense and pace either the atrium or the ventricle
Possible to have only atrial, only ventricular or both atrial and ventricular pacing
DDD pacer is a common example of this

14. Atrial Spike
Ventricular Spike

15. AV Pacing
Ventricular Pacing

16. Magnet Placement
The EKG technician should perform a 12 lead cardiogram and then a rhythm strip with a magnet over the pacer
Often a very poorly understood concept by the non-cardiologist
Does not inactivate the pacer as is commonly believed
Activate a lead switch present in the pacemaker which converts the pacer to a asynchronous or fixed-rate pacing mode
Inhibits the sensing function of a pacemaker

18. Class I Indications For Permanent Pacing
Third degree AV block associated with:
Symptomatic bradycardia
Symptomatic bradycardia secondary to drugs required for dysrhythmia management
Asystole > 3 seconds or escape rate < 40
After catheter ablation of the AV node
Post-op AV block not expected to resolve
Neuromuscular disease with AV block

19. Indications Symptomatic bradycardia from second degree AV block
Bifascicular or trifascicular block with intermittent third degree or type II second degree block
Sinus node dysfunction with symptomatic bradycardia
Recurrent syncope caused by carotid sinus stimulation

20. Indications Post myocardial infarction with any of:
Persistent second degree AV block with bilateral bundle branch block or third degree AV block
Transient second or third degree AV block and bundle branch block
Symptomatic, persistent second or third degree AV block

21. Infections Pacemaker insertion is a surgical procedure:
1% risk for bacteremia
2% risk for wound or pocket infection
Usually occur soon after pacer insertion
Presence of a foreign body complicates management

22. Infection Cellulitis or pocket infection: Bacteremia: Staphylococcus
Tenderness and redness over the pacemaker itself
Avoid performing a needle aspiration – damage the pacer
Bacteremia: Staphylococcus
aureus and Staphylococcus epi 60-70% of the time
Empiric antibiotics should include vancomycin pending culture

23. Infection Consult the pacemaker physician Draw blood cultures
Give appropriate antibiotics
Frequently the pacer and lead system need to be removed

24. Case 1
67 year old male presents to the emergency room 12 hours after insertion of a pacemaker complaining of left sided chest pain and shortness of breath
PR96, RR 33, BP 125/85, Oxygen saturation 88% RA
CXR as shown

26. Pneumothorax Occurs during cannulation of the subclavian vien
Incidence - ?? Cardiologist dependent
Treatment:
Asymptomatic or small – observation
Symptomatic or large – tube thoracostomy
Notify the pacemaker physician

27. Case 2
72 year old male presents to the emergency room after a fall, tripped over a bath mat, no LOC
Shortened and rotated left leg
Past history – pacemaker, hypertension
Nurse does an routine pre-op CXR and EKG

30. Septal Perforation
Usually identified at the time of pacer insertion but leads can displace after insertion
Can occur with transvenous pacer insertion
Keys diagnosis are a RBBB pattern on EKG and a pacer lead displaced to the apex of the heart on CXR

31. Septal Perforation Management: Notify the pacer service
Pacer wire has to be removed but not emergently
Small VSD which heals spontaneously

32. Conclusions Pacemakers are becoming more common everyday
We need to understand basic pacing terminology and modes to treat patients effectively.
Most pacer malfunctions are due to failure to sense, failure to capture, over-sensing, or in-appropriate rate
Standard ACLS protocols apply to all unstable patients with pacemakers.