High Efficiency Cardiac System for Cardiac Therapy

8/4/2019 High Efficiency Cardiac System for Cardiac Therapy

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HIGH EFFICIENCY CARDIAC

SYSTEM FOR CARDIAC THERAPY

-AMOL PARAB

-VIKRAMADITYA DANGI-KSHITIJ PAWAR


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HUMAN HEART

1)Muscular organ responsible for pumping blood through blood vessels byrepeated , rhythmic contractions.

2) cardiac comes from Greek word KARDIA related to the heart

3)Average human heart 72 BMP ( 2.5 billion times in 66 yrs)

4) It is effectively a meshwork of cardiac muscle cells interconnected by

contiguous cytoplasmic bridges


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Need for Circulation

1) To deliver food materials and oxygen to the

tissues

2) To remove waste products and heat

3) Done by diffusion in small animals, but in largeanimals its a must


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Functioning

1) Right side collects deoxygenated blood in the right atrium

and pumps it into the lungs via right ventricle

2) CO2 , O2 by process of diffusion

3) Left side -- collects oxygenated blood in the left atrium andpumps it back into the body via left ventricle

4) Arteries supply the pure blood

5) Veins collect impure blood


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NEED FOR CARDIAC THERAPY

To avoid :

1) ARRHYTHMIAS

2)MYOCARDIAL INFARCTION


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ARRHYTHMIAS

1)An arrhythmia is a problem with the speed or rhythm of the

heartbeat.

2) A heartbeat that is too fast is called tachycardia

3) A heartbeat that is too slow is called bradycardia.

4)Common among older adults

5) Causes : heavy alcohol, smoking

6) Symptoms : Shortness of breath

Chest pain

Arrhythmic palpitations


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Myocardial Infarction

1)Myocardial infarction, commonly referred to as a heart attack,

occurs when one or more coronary arteries become suddenly

blocked, resulting in heart muscle death.

2) Myocardial infarction results from coronary artery disease (CAD),

which is an accumulation of plaque inside the coronary blood vessels.

3) When one of these plaques rupture, a clot forms rapidly at the site

and causes a sudden obstruction of blood flow in the coronary artery.

4)Symptoms : Shortness of breath and chest pain


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TREATMENT

1)Angioplasty is the technique of mechanically widening a narrowed or

obstructed blood vessel

2) An empty and collapsed balloon on a guide wire, known as a balloon

catheter is passed into the narrowed locations and then inflated to a

fixed size using water pressures some 75 to 500 times normal blood

pressure (6 to 20 atmospheres).

3) The balloon crushes the fatty deposits, opening up the blood vesselfor improved flow, and the balloon is then deflated and withdrawn.


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Problems with traditional methods

1) Large size

2) Poor efficiency (less than 20 %)

3) Away from surgical area

4) Use of co-axial cables resulting in power losses of 6 dB

5) Solid-state devices (smaller size) but generated heat

These problems can be solved by using microwave devices whichgenerate less heat and only heat the desired tissue without affecting

the surroundings .


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MICROWAVE ENERGY GENERATOR

CONCEPT

1) Microwave energy sources for cardiac surgery must be

capable of delivering up to 80 Watts at 2.54 GHz.

2) The primary technology for these sources is vacuum-tube

3) Artisan Laboratories Corporation has developed a new

microwave source called Ultralight Microwave Energy Source

for generating, amplifying, distributing and controlling

high power microwave energy for cardiac surgery.

4) In addition their concept allows for the use of optical fiber for

distribution of control signals. Using a fiber optic cable for

signal distribution has many benefits over coaxial cables

including: low loss, high isolation, small size, improved

flexibility.


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Continued..

1)The microwave input signal is compared against a

reference signal in a pulse width modulator (PWM)

generator.

2)The output is a pulse-width modulated signal

that drives an optical transmitter and is directed to a

microwave photonic amplifier via a fiber optic cable.

3)The optical PWM signal is used to drive the high efficiency

microwave photonic amplifier that converts the signal back to

microwaves


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CONTINUED..

1)The design and fabrication of the system consisted of building

three main circuits: PWM Generator, Laser Transmitter andthe Microwave Photonic amplifier.

2)The PWM generator uses a high speed comparator to convert the analog

or microwave signal to a PWM.

3) The PWM output is used to modulate a laser transmitter and the resultingsignal is transmitted over a fiber to the microwave photonic amplifier

4) They achieved 80 % maximum efficiency with 55 %

power added efficiency at a level of 100 mW.

COMPUTER AIDED DESIGN OF


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COMPUTER AIDED DESIGN OF

MINIATURIZED ANTENNAS FOR

MICROWAVE CARDIAC ABLATION

1) In this methods of designing miniaturized antennas for the application

of microwave ablation for the cure of cardiac arrhythmias.

2) Finite Difference Time Domain and Finite Element methods are used to

first design and optimize miniaturized antennas.

3) The overall size of the antennas has 2.5mm outer diameter that is

suitable for intravenous catheterization delivery.

4) Bioheat transfer equation is solved using finite difference method and its

predicted temperature results are compared with the results obtained from

the experiments.


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CONTINUED..

1)Cardiac ablation refers to the procedure of destroying

myocardial tissue that is responsible for causingarrhythmias.

2)This procedure utilises external electromagnetic energy to raise

the local temperature of the problematic site that originates the

arrhythmia to produce a lesion so that the conduction of

undesirable electrical signal is eliminated.

3)Over the past years, the radio-frequency (RF) had become a

popular mode of energy delivery system for cardiac ablation.

4)However, one of the disadvantages of RF ablation is that it

requires constant contact between the RF electrode and themyocardium tissue.


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Continued..

1) In contrast to RF energy, microwave energy causes dielectric heating by

stimulating the oscillation of dipoles within the myocardium.

2) Taking the advantage of this property, microwave antenna is capable

of depositing energy deep within the myocardium and hence obtaining greater

lesion depth than RF ablation.


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Continued

1) During the ablation procedure the temperature differences

are usually more than 1 O"C, therefore, the temperature

dependent nature of the myocardium tissue's dielectric

constant is an important factor and must be

considered during modelling.

2)Once the near-Electric-field values of the antenna are

obtained, the Specific Absorption Rate (SAR) is calculated.

3)Using the calculated SAR, one is able to predict the

temperature profile of the antenna by applying the Bio-HeatTransfer Equation (BHE) and solved by using the FD

technique.


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Continued..

1)A novel coaxial slot array antenna is extensively analysed and tested using the

FDTD technique.

2)Overall, the CSA antenna is capable of generating temperatures of greater than

55 degrees required forirreversible lesion formation in a very short period of time.

3)The lesion sizes, in terms of width and depth, are controlled by varying the

microwave energy and ablation duration. In relatively short periods of ablation

time, the CSA antenna is capable of producing lesions of sufficient depth for

transmural atrial ablation. In some cases, transmural ventricular ablation is also

achieved.

4) Thus optimum temperature can be obtained.


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MICROWAVE TOMOGRAPHY

1) Microwave tomography is a novel, early development stage imaging modality

with a number of potentially attractive biomedical applications.

2) A high contrast between properties of normal and diseased tissue

is a great potential of this imaging modality.

3)With microwave tomography tissues are differentiated and, consequentially,

can be imaged, based on differences in dielectric properties.

4)It has been proven in a number of studies that dielectric properties of biological

tissues are a strong indicator of its functional and pathological

conditions.


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Continued..


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Continued..

1) The system operates at frequencies of 0.9-1.0GHz.

2) The operation frequency can be changed within the optimum

spectrum for tomographic imaging.

3)The working chamber consists of a cylinder with diameter of 120cm and

height of 135cm, filled with matching solution.

4)In microwave tomographic experiments the object under study is placed

into the central part of the working chamber, which is filled

with matching solution.

5) The major purpose of the matching solution is to decrease the high

reflection of EM fields from the air-body boundary. Various types of

matching solutions have been used: deionized water, saline and fattysolutions with dielectric constants varying in between 40-

80 at room temperature.


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DIATHERMY

1) In the natural sciences the term diathermy means "electricallyinduced heat" and is commonly used for muscle relaxation.

2) It is also a method of heating tissue electromagnetically or

ultrasonically for therapeutic purposes in medicine.

3) Surgical diathermyis usually better known as "electrosurgery

4) Electrosurgery and surgical diathermy involve the use of high

frequency A.C. electrical current in surgery as either a cutting

modality, or else to cauterize small blood vessels to stop

bleeding.

5) This technique induces localized tissue burning and damage, the

zone of which is controlled by the frequency and power of the

device.


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Continued..

1) Diathermy involves current frequencies between 400KHz to 10MHz, thus

allowing currents of 500mA to safely pass through patient (100mA at a

household frequency of 50Hz will cause electrocution.

2)Monopolar diathermy

Electrical plate is placed on patient and acts as indifferent electrode

Current passes between instrument and indifferent electrode

As surface area of instrument is an order of magnitude less than that of

the plate

Localized heating is produced at tip of instrument

Minimal heating effect produced at indifferent electrode

3) Bipolar diathermy

Two electrodes are combined in the instrument (e.g. forceps)

Current passes between tips and not through patient


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Microwave diathermy

1) Its frequency is 27,120,000 cycles per second and the

wavelength is 11 metre

2) High frequency waves are generated by Magnetron

1) Circuit Description: Diathermy machine consist o f two main

circuits ;an oscillating circuit, which produces the high

frequency current and a patient circuit which is

connected to the oscillating circuit and through which the

electrical energy is transferred to the patient.

2) Uses: pain bacterial infection boils


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Continued..

More uses:

1.Inflammation of shoulder joint

2.Inflammation of Elbow Joint (Tennis Elbow)

3.Degeneration of joints of neck (Cervical Spondylosis)

4.Degeneration of joints like knee and hip (Osteoarthritis)

5.Ligament Sprains in knee joint

6.Low Back Ache

7.Plantar fascitis (Heel Pain)

8. Sinusitis

SIE METHOD OF ANALYSING


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SIE METHOD OF ANALYSING

MICROWAVE FIELDS

OF A 3D HEART MODEL1) There are several important factors when using microwaves devices

(wavelengths of 10 cm to 1 mm) which will determine their successful

application in medical procedures.

2) The first factor is the wavelength of the microwave may be of the same order as the

size of the tissue to be incinerated and permits us to eliminate only the unhealthy

tissue.

3)The second factor is the MC used for ablation is very minute and when using

this procedure it greatly diminishes the risks of many complications as

compared to traditional surgical operations.

4) The third factor is that when doctors monitor a patient using microwaves devices

like ours he can keep informed of the patients vital signs such as blood pressure

and pulse


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Continued..

1 Our SIE method was used for the numerical analysis of a

microwave electric field on a heart model when a MC was placed

inside.

2. We have seen that our SIE method enables one to optimal the size

and shape of a MC when used to remove abnormal tissue in the

heart.3. The imaginary parts of the permittivities of the heart media are

quite large; this causes the attenuate of the microwave energy in

the media. We see that the amplitude of the electric field decreases

while moving away from the MC tip.


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Continued

4. We see that the microwave electric field distribution

inside of the heart model depends on the shape and

location of the microwave catheter.

5. We discovered that the electric field distribution most

suitable for microwave ablation is when a curved microwavecatheter is pressed against the top lateral surface of left

heart cavity. In this case the electric field distribution in the

transversal cross-section has only one maximum which

means that the electric field is concentrated

only on the tissue to be removed. Also the magnitudes of

electrical field distribution in the longitudinal cross sectionof the heart model are less than in other cases


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High Efficiency Cardiac System for Cardiac Therapy