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Cardiac pacemaker

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Cardiac pacemaker

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Cardiac pacemaker
Rupon bhowmik
dept of medical physics and biomedical engineering,gono university,Dhaka,Bangladesh

Cardiac pacemaker
Rupon bhowmik
dept of medical physics and biomedical engineering,gono university,Dhaka,Bangladesh

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Cardiac pacemaker

  1. 1. Presentation on Cardiac pacemaker
  2. 2. Objectives • What is cardiac pacemaker ? • History of cardiac pacemaker • When are pacemaker used ? • Types of cardiac pacemaker • Pacemaker circuit • Cardiac pacemaker design • Procedure during the pacemaker implanted • Technical specification of a pacemaker • Advantage and Disadvantage of pacemaker- • Conclusion • Reference 2
  3. 3. What is cardiac pacemaker ? • A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate. • Pacemakers are used to treat arrhythmias . Arrhythmias are problems with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm. 3
  4. 4. History of cardiac pacemaker- In 1932 Albert Hyman Concept of artificial pacemaker, magneto-generator to power up electrode. In 1950 john Hopps 1st trans-cutaneous pacemaker.Vaccum tube technology & direct AC power supply is used. In 1958 Dr.Ake senning 1st implanted (trans- venous) pacemaker. In 1959 W.M Chardack 1st successful long term implantable pacemaker. 4
  5. 5. When are pacemaker used ? • Pacemakers may be prescribed for a number of condition,including : • Bradycardia - A condition in which the heart beats too slowly. • Atrial fibrillation – A common heart rhythm disorder in which the heart beats too fast and chaotically. Which disorder can be treated by pacemaker. • Heart failure – A condition in which the heartbeat is not strong enough to carry a normal amount of blood and oxygen to the brain and other parts of the body. 5
  6. 6. Types of cardiac pacemaker- • The pacemaker’s primary function is the heart its secondary function is sensing for intrinsic signals.Pacemaker can be categorized in several ways- they can be defined with a code of three letters or they can be unipolar , bipolar, single-chamber , dual-chamber pacemaker. • First , we will discuss the codes used to define different types of pacemakers- Single chamber pacemaker Dual chamber pacemaker Biventricular pacemaker Rate responsive pacemaker 6
  7. 7. Types of cardiac pacemaker- • Single chamber pacemaker have one wire that is placed in the right upper chamber (atrium) or lower chamber (ventricle). • Dual Chamber pacemaker have two wires, one in the atrium and one in the ventricle. Fig : Single chamber pacemaker Fig : Dual chamber pacemaker 7
  8. 8. Types of pacemaker- • Biventricular pacemaker have three wires , one is in the right atrium , one in the right ventricle and a third in the left ventricle. This pacemaker used to improve pumping in patients with heart failure. • Rate responsive pacemaker adjust rate to a patient’s level of activity. They pace faster when a patient is exercising and slower when a patient is resting. Fig : Biventricular pacemaker Fig : Rate responsive pacemaker 8
  9. 9. Pacemaker Circuit- • A pacemaker has three components :  This is kept in small metal case and the circuit is connected to a battery. The circuit generates the impusle at a specific time.  These insulated wires carry the impusle to the heart.  This is kept in the hospital or clinic to program the pacemaker and to adjust the setting of impulse amplitudes and frequency. The programmer is a specialized computer with a hardware and software interface. 1.Pacemaker electronic circuit 2. Pacing leds 3. Programmer 9
  10. 10. Pacemaker Circuit- Reversion circuit Sensing circuit Refractory Circuit Timing circuit Pulse Width circuit Rate Limit circuit Output circuit Rate Slowdown circuit Voltage monitor Energy Compensation circuit Figure : Block Diagram of Pacemaker 10
  11. 11. Cardiac pacemaker design- • They are packaged in hermetically (airtight) sealed metal packages. • Titanium • Stainless steel • Power supply : Currently Lithium Iodide batteries are used • Increased life time • Open circuit voltage of 2.8 V. • Highly reliable • Relatively High source resistance is a major limitation Timing Circuit : Advanced pacemakers have timing circuits to determine when a stimulus should be applied to the heart. Output Circuit/Pulse Generator : Produces the actual electrical stimulus that is applied to the heart. 11
  12. 12. Cardiac pacemaker design- • Generates an electrical stimulus pulse that has been optimized for stimulating the myocardium through the electrode system that is being applied with the generator. • Constant-voltage or constant-current amplitude pulses are the two usual types of stimuli produced by the output circuit. • Output Circuit : Constant-voltage amplitude pulses are typically in the range of 5.0 to 5.5 V with a duration of 500 to 600 µs. Pulse rate range 70 to 90 beats per minutes. • Lead Wires : Must be mechanically strong. Must maintain good electrical insulation to prevent the possibility of shunting important stimulating current away from its intended point of application on the heart. • Electrodes : Can be placed on the external surface of the heart (epicardial electrodes). Made of materials that do not dissolve during long term implantation. 12
  13. 13. Procedure during the pacemaker implanted- Generally, a pacemaker insertion follows this process:  You will be asked to remove any jewelry or other objects that may interfere with the procedure.  You will be asked to empty your bladder prior to the procedure.  An intravenous (IV) line will be started in your hand or arm prior to the procedure for injection of medication and to administer IV fluids, if needed.  You will be connected to an electrocardiogram (ECG or EKG) monitor that records the electrical activity of the heart and monitors the heart during the procedure using small, adhesive electrodes.  Large electrode pads will be placed on the front and back of the chest.  Once the lead wire is inside the heart, it will be tested to verify proper location and that it works. There may be one, two, or three lead wires inserted, depending on the type of device your doctor has chosen for your condition 13
  14. 14. Procedure during the pacemaker implanted-  The ECG will be observed to ensure that the pacer is working correctly.  The skin incision will be closed with sutures, adhesive strips, or a special glue.  A sterile bandage or dressing will be applied. Figure : Location of pacemaker implant 14
  15. 15. Technical specification of a pacemaker- Pacing Modes VVI,VVT,VVO,AAI,AOO,OFF Basic Pacing rates Between 30bpm and 120bpm Sensitivites Between 0.5mv and 4.0mv ,in step of 0.5mv Electrical configuration for pacing Monopolar/bipolar Initial voltage 2.8v Electrode material Titanium coated with iridium oxide. Lead body Polyurethene Means of attachment Titannium alloy screws 15
  16. 16. Advantage and Disadvantage of pacemaker- ADVANTAGE  The pacemaker uses electrical impulse to stimulate faster rate when the natural system of heart falling to regulate heart beat pacing.  For biventricular pacemaker, its work to ensure the ventricle and atria to work together and improve the heart pumping efficiency.  Used to rectify that causes the heart ventricle to quiver instead than beat in normal rhythm.  By using pacemaker the heart failure can be prevent by coordinate electrical signal between ventricles of the heart. DISADVANTAGE  Pacemaker implantation may reveal patients to surgical site infections. Apart from that they can get allergic to anesthesia and also became swollen and bruising.  The pacemaker users have to be careful with electrical appliances such as cell phone, microwave oven and also high tension wire.  Not only routines that need to be taken into account, but they must also be wary of medical equipment, such as MRI with very high magnetic forces and shockwave lithotripsy to get rid kidney stones.  All these can disrupt the electrical signalling of pacemaker and stop it from functioning and can cause fatal. 16
  17. 17. Conclusion- • The artificial pacemaker has been around for over 50 years. Technology has allowed us to advance tremendously int he field of medicine. Today engineers are find ways for creating longer lasting batteries and a way to develop a and replace the actual pacemaker located in our bodies now. With these advances in technology, artificial pacemakers are changing the lives of thousands every year. 17
  18. 18. Reference- • Handbook of Biomedical Instrumentation,R S khandpur,Tata McGraw-Hill,2003. • http://www.hopkinsmedicine.org/healthlibrary/test _procedures/cardiovascular/pacemaker_insertion _92,P07980 • https://www.nhcs.com.sg/patientcare/ConditionsA ndTreatments/Pages/CardiacPacemakerImplanta tion.aspx • Basic principal of cardiac pacemaker Technology, D. Korpas, Implantable Cardiac Devices Technology, Springer Science+Business Media New York 2013. 18
  19. 19. Thank you for your attention 19

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