pacemaker presentation

8/4/2019 Pacemaker Presentation

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Therapeutic and Prosthetic

Devices

Part I : Cardiac Pacemaker

Dr. Mohamad O. Diab

Assistant ProfessorCollege of Engineering

Hariri Canadian University (HCU)


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Outline

Introduction

Physiology of the heart

Pacemaker Asynchronous

Synchronous

Demand type

Aterial synchronous type

Variable rate type


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Therapeutic and prosthetic

Instruments Electrically stimulate different parts of the body to relief pain,

cure diseases, or replace damaged biological organ in thebody.

Examples of Therapeutic and prosthetic devices:

Cardiac Pacemakers

Ventilators

Heart-Lung machines

Artificial Kidney Diathermy Devices

Electrosurgical Instrument

Cochlear Implant

Eye Bionic


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Physiology of the heart


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Electrical conduction system

of the heart
http://fr.wikipedia.org/wiki/Image:ECG_Principle_fast.gif


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Cardiac Pacemakers

Cardiac Pacemaker:

An electric stimulator that produces periodic electric pulses that are

conducted to electrode on the surface of the heart, within the heart

muscle, or within the cavity of the heart.

Two Type of Pacemakers:

1) Asynchronous cardiac pacemaker2) Synchronous cardiac pacemaker


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Types of pacemakers

Pacemakers

Asychronous Sychronous

Atrial sychronous Demand type Variable rate


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Asynchronous Cardiac PacemakersPower Supply: Lithium iodide

Cathode reaction: Li Li+

+ e-

Anode reaction at the Anode: I2 + 2e- 2I-

Timing Circuit: pulse rate is 70 to 90 pulse per minute

Output Circuit:

Constant-Voltage Amplitude pulses: 5.0 to 5.5 V with duration of 0.5

to 0.6 msec.

Constant-current amplitude pulses: 8 to 10 mA with pulse duration

from 1.0 to 1.2 ms.

Block diagram of an asynchronous cardiac pacemaker


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Figure 1. Two of the more commonly applied cardiac pacemaker electrodes

(a) Bipolar intraluminal electrode. (b) Intramyocardial electrode.

Lead Wires and Electrodes


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Synchronous Pacemakers

Provide electric stimulus when the cardiac normal rhythm is stopped.

Two type of synchronous pacemakers

1) The demand pacemaker (Irregular SA node firing)

2) The atrial-synchronous pacemaker (AV node is not working)

Figure 2. A demand-type synchronous pacemaker


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Figure 3. An atrial-synchronous cardiac pacemaker, which detects

electric signals corresponding to the contraction of the atria and uses

appropriate delays to activate a stimulus pulse to the ventricles. Figure

13.5 shows the waveforms corresponding to the voltages noted.

Atrial-Synchronous Pacemaker


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Rate-Responsive Pacemaker

Physiological Variable SensorRight-ventricle blood temperature Thermistor

Venous blood oxygen saturation Optical Oximeter

Respiratory rate and/or volume Thoracic electric-

impedance

Physiological variables are used to control the pulse rate of the

rate-responsive pacemakers


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Any Questions

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