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Transcript
Pacemaker for beginners
KITA yosuke
Iizuka Hospital
Objectives
 Review
basic pacemaker terminology
and function
 Discuss diagnosis and management of
pacemaker emergencies
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
Pacemaker Components
 Pulse
Generator
 Electronic Circuitry
 Lead system
Pulse Generator
 Lithium-iodine
cell is the current
standard battery
 Advantages:
life – 4 to 10 years
 Output voltage decreases gradually with
time making sudden battery failure unlikely
 Long
Electronic Circuitry
 Determines
the function of the
pacemaker itself
 Utilizes a standard nomenclature for
describing pacemakers
Pacemaker Nomenclature
I
II
III
IV
V
Chamber
Paced
Chamber
Sensed
Response to
Sensing
Rate Modulation,
Programmability
Antitachycardia
Features
A=Atrium
A=Atrium
T=Triggered
P=Simple
P=Pacing
V=Ventricle V=Ventricle I=Inhibited
M=Multiprogrammable
S=Shock
D=Dual
D=Dual
D=Dual
R=Rate Adaptive
D=Dual
O=None
O=None
O=None
C=Communicating
O=None
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
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
Pacer spike
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
Atrial Spike
Ventricular Spike
AV Pacing
Ventricular Pacing
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
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
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
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
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
Infection

Cellulitis or pocket infection:



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
Infection
 Consult
the pacemaker physician
 Draw blood cultures
 Give appropriate antibiotics
 Frequently the pacer and lead system
need to be removed
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
Pneumothorax
 Occurs
during cannulation of the
subclavian vien
 Incidence - ?? Cardiologist dependent
 Treatment:
or small – observation
 Symptomatic or large – tube thoracostomy
 Asymptomatic
 Notify
the pacemaker physician
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
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
Septal Perforation
 Management:
 Notify
the pacer service
 Pacer wire has to be removed but not
emergently
 Small VSD which heals spontaneously
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 inappropriate rate
 Standard ACLS protocols apply to all
unstable patients with pacemakers.