2. The rhythmic beating of heart is due to the
SA node situated at the R.A of heart
Some situations this natural pace maker stop
functioning
Becomes unreliable
Pulse does not reach the heart due to
conduction block
Normal synchronization of heart get
disturbed
3. NEED OF C.P.M
By giving external electrical stimulation
impulses to the heart muscle, it is possible to
regulate heart rate
These impulses are given by an electronic
instrument called a pacemaker
4. CONSISTS OF TWO PARTS
PULSE GENERATOR
ELECTRONIC UNIT
Generates stimulating impulse
Rate and amplitude will be controlled
THE LEAD
Carriesthe electrical pulse from Pulse Generator
to the heart
5. ELECTRODE ARRANGEMENT
BIPOLAR ARRANGEMENT
Twoelectrodes are placed on the heart for
stimulation
UNI POLAR ARRANGEMENT
One electrode is placed on the heart and the
other electrode is placed elsewhere in the body
6. TYPES OF PACE MAKERS
EXTERNAL PM
IMPLANTABLE PM
Fixed Rate PM
Demand PM
R wave triggered PM
R wave blocked PM
Atrial Triggered PM
Dual chamber PM
7. EXTERNAL P M
Used when short term pacing is required
Used for patients recovering from cardiac
surgery
Applied a 80 mA pulse through 50 cm 2
electrode on the chest
8. THE PULSE MAY BE DELIVERED…
Continuously-When the HR is going below the
preset value, artificial PM is activated
It is independent of electrical activity of heart
On Demand (R-wave synchronous Pacing)-
Normally the PM wont be working
When HR falls below preset value PM is
activated
Beat to beat examination of time interval b/w
two R waves is done
9. BASED ON TYPE OF O/P WAVE FORM
Voltage PM (voltage O/P remains constant)
Current PM (Current in the ckt is determined by
the internal resistance)
Current Limited Voltage PM
10. IMPLANTABLE PM
Implanted beneath the skin
O/P leads are directly connected to heart
muscle
Powered by small batteries
Highly reliable components
Power source for long period
Biological inert material
Properly isolated from body fluids
11.
12. PACKAGING OF IMPLANTABLE PM
Circuit and power source is packed
separately
Sealed within the stainless steel case
Case is made from titanium or 316 L
stainless steel
Pure platinum conductor for electrodes
13. POWER SOURCE
Mercury Batteries
1.35 V
3-5 batteries
Disadvantages like dendritic mercury growth
Corrosion
Leakage etc
14. Biological power source-Galvanic cells using
body fluids as electrolyte
Nuclear batteries- Plutonium-238
Lithium cells-
