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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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