A basic note on pacemaker that will be usefull to undergraduate students to attain a brief and basic knowledge on pacemaker. when the natural pacemaker of the heart becomes unrelyable , an artificial pacemaker needs to be implanted in the which will cause contraction of the myocardium by initiating electrical activity of the heart.

1. By
Anjuman Nahar
pacemaker

2. Anatomyandphysiologyof the circulatory system
Circulatory system is a complex system that
transports blood, nutrients, oxygen and
carbon dioxide within the body.

4. Conducting system of the heart
Regular contractions of the heart are managed by the heart’s
electrical system, which has three important components:
Sinoatrial (SA) node : known as the heart’s natural pacemaker, leading
the rhythm in a healthy heart
Atrioventricular (AV) node : the bridge between the atria and
ventricles, passing electrical signals from
the atria to the ventricles
His & Purkinje system : carries electrical signals throughout the
ventricles. It includes the His bundle, right
bundle branch, left bundle , branch, and
Purkinje fibers

5. pacemaker
electric stimulator device
produces periodic electric pulses to the heart.
Causes the heart to contract
Used in cases of heart block or MI.

6. Need for cardiac pacemaker
• The rhythmic beating of the heart is due to the
triggering pulses that originate in an areaof a
specialized tissue in the right atrium of the heat. This
area is known as the SA node.
• In abnormal situations if the SA node does not function
properly or becomes unreliable, the normal
synchronization of the heart gets disturbed.
• When monitored this menifests as decrese in heart
rate or changes in ECG readings.
• However by giving external electrical stimulation by a
cardiac pacemaker these findings can be corrected.

7.  Parts of the pacecemaker
1. an electrcical unit that generate electrical pulses of
controlled rate and amplitude.
2. the lead that carries the pulses from the pulse
generator to the heart.
 Arrangement of the electrodes
1. Unipolar
2. Bipolar
 Properties of the lead wires
1. Good conductors
2. Mechanically strong- [interwound, helical, sillicon-
rubber encapsulation]
3. Good insualtion
4. Platinum and alloys of platinum[elgiloy, MP35N]

8. Types of pacemakers
External pacemakers
• used temporary cases or in cases of emergency
like in ICU or awaiting for implantation.
• Pulses may be delivered either
continuously[asynchonous] or in
demand[synchronous].
• Asynchronous pacemaker provides a constant
rate of pulses continuously.
• Synchronous pacemaker provides stimulation on
demand i.e. when there is need of stimulation.

9. Block diagram of asynchronous
pacemaker
Power circuit
Oscillator
circuit
Pulse output
circuit
electrodes
Timing circuit Output circuit electrodes
Block diagram of synchronous
pacemaker
Reset circuit amplifier

10. Implantable pacemaker
• It is entirely implanted beneath the skin
• The various types of implantable pacemaker are
1. Fixed rate pacemaker: in patients with permanent heart
block
2. Demand pacemaker: they stay in a standby mode during
natural beats.
3. Rate responsive pacemaker: extra sensor controls
individuals movement and breathing.
4. Biventricular: uses three leads- right atrium, right
ventricle & left ventricle.
5. Dual chamber: uses two electrodes, each in the upper and
lower chamber.
6. Single chamber: use only one electrode in either right
atrium or ventricle when SA node generates improper
pulses.

11. Advantages
• It mimics natural action of the heart.
• Generates a faster electrical stimulation to
produce heart beats
• A biventricular pacemaker coordinates the
contraction of atria and ventricles and improves
effective pumping of the heart.
• It is used to correct atrial fibrillation
• Cardiac failure can be prevented as it can detect
electrical signals between the ventricles of the
heart.

12. Disadvantages
• Pacemaker implantation may expose patients to
different issues such as oversensitive to sedation
and susceptible to swelling and bruising.
• There may be a need of lifestyle modification
such as users must be cautious around electrical
apparatus such as mobile phones, microwaves,
high tension wires etc.
• Pacemaker users should be cautious with clinical
hardware instruments such as MRI

13. Complications
• Tachycardia
• Infectins near the site where the device is
planted
• Damage to blood vessels or nerves near the
pacemaker
• Blood clots at the site of insertion of device

14. Pacemaker indications
• Sinus node dysfunction
• Acquired AV block
• Chronic bifascicular block
• After the acute phase of myocardial infarction
• Neurocardiogenic syncope
• Hypersensitive carotid sinus syndrome
• Post cardiac transplantation
• Hypertrophic cardiomyopathy
• Pacing to prevent tachycardia

15. THANKYOU