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Cardiac Pacemaker System

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Cardiac Pacemaker System Presented by: Wong Shin Shin (KEU 98038) McCartney Dandot (KEU 97010) Scope of presentation Introduction A prelude: normal heart activity ... – PowerPoint PPT presentation

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Title: Cardiac Pacemaker System


1
Cardiac Pacemaker System
  • Presented by
  • Wong Shin Shin (KEU 98038)
  • McCartney Dandot (KEU 97010)

2
Scope of presentation
  • Introduction
  • A prelude normal heart activity
  • Pacemakers its past history
  • Conception of idea
  • Invention process
  • Clinical prototyping
  • Pacemakers Current development
  • Pacemakers its future trend
  • Comment and conclusion

3
Introduction
  • A pacemaker system is a device capable of
    generating artificial pacing impulses and
    delivering them to the heart.
  • It consists of a pulse generator and appropriate
    electrodes.
  • In the past few years electronic pacemaker
    systems have become extremely important in saving
    and sustaining the lives of cardiac patients
    whose normal pacing function of the heart have
    been impaired.

4
Normal heart activity
5
Why need the pacemakers?
  • Sometimes a heart's natural rhythm is interrupted
    or becomes irregular- bradycardia
  • The heart's natural pacemaker sends out
    electrical impulses too slowly due to a diseased
    SA node.
  • Or, the electrical impulses may be blocked along
    the pathway through the heart, -"heart block."
  • Symptoms dizziness, extreme fatigue, shortness
    of breath, or fainting spells.
  • A pacemaker stimulates the heart muscle with
    precisely timed discharges of electricity that
    cause the heart to beat in a manner very similar
    to a naturally occurring heart rhythm.

6
Pacemakers its past history Conception of idea
  • Cloroform was popular in the late 1980s, but when
    it was used, occasional respiratory and cardiac
    arrest occurred, as an occasional complication of
    cloroform anesthesia
  • To restart the heart, Green in the United Kingdom
    1872 applied the output of a 300V battery using
    hand-held electrodes applied to the base of the
    neck and the lower left chest.
  • Interestingly, the electrode applied to the lower
    left chest stimulated the ventricles. The other
    electrode applied to the base of the neck
    delivered current to the phrenic nerve and
    twitched the diaphragm, causing a brisk
    inspiratory motion.

7
Invention process
  • In 1882, Ziemssen in Germany applied cardiac
    pacing to a 42-year-old woman who had a large
    defect in the anterior left chest wall following
    resection of an enchondroma.
  • The heart was only covered by skin, on which
    Ziemssen placed electrodes.
  • Using induction-coil shocks, he paced the heart
    with a stimulus frequency higher than that of the
    normal heart rate.

8
Clinical prototyping
  • Dr. Rune Elmqvist designed the world's first
    implantable pacemaker. It included a pulse
    generator delivering about two volts with an
    impulse period of two milliseconds. The original
    transistors showed large leakage currents and
    were found not suitable.
  • Problems of the early pacemakers breakage of
    electrode wires, short battery life, the need for
    surgery for pacemaker and lead implantation
  • Chardack 1961 described a durable electrode
    wire made from the alloy that is used in the
    escapement spring of watches. It was sutured to
    the epicardium, and a thoracotomy was required.

9
  • Within a year, Lillehei et al. 1960 reported
    the use of right ventricular catheter electrodes
    with an external pacemaker to pace 66 patients.
    The pacemaker was built by Earl Bakken, a
    biomedical engineer, the founder of Medtronic
    Inc. in 1949, which soon became the pioneer
    pacemaker company.
  • The pacemaker manufactured is called the
    Greatbatch-Chardack pacemaker. It consisted of a
    transistor oscillator and an amplifier energized
    by 10 mercury-zinc cells. The 10 cells and
    electronic circuitry were potted in epoxy and
    covered by a double shell of Silastic. The
    electrode used was about the size of a postage
    stamp

10
Earl's first wearable, battery-powered,
transistorized cardiac pacemaker
11
Invention process (cont.)
  • From Earl E. Bakken's Book "One Man's
  • Full life"
  • "Back at the garage, I dug out a back
    issue of Popular Electronics magazine in which I
    recalled seeing a circuit for an electronic,
    transistorized metronome. The circuit transmitted
    clicks through a loudspeaker the rate of the
    clicks could be adjusted to fit the music. I
    simply modified that circuit and placed it,
    without the loudspeaker, in a four-inch-square,
    inch-and-thick metal box with terminals and
    switches on the outside - and that, as they say,
    was that. "

12
Schematic drawing of a pacemaker
13
A closer look at the pacemaker
The programmer is a telemetry device used to
provide two-way communication between the
generator and the clinician. It can alter the
therapy delivered by the pacemaker and retrieve
diagnostic data that are essential for optimally
titrating that therapy.
14
Pacemaker today
15
Pacemaker Current Development
  • Comprise of 3 distinct components
  • Pulse generator
  • Lead
  • Programmer
  • Come in different shapes and sizes
  • Small and lightweight (22-50gms)
  • Depending upon patients heart condition,
    physician will prescribe the number of chambers
    to be paced and type of pacing

16
Number of Chambers
  • A single-chamber pacemaker paces either the right
    atrium or the right ventricle, with one lead.
    Most common is the right ventricle.
  • A dual-chamber pacemaker paces both the right
    atrium and right ventricle of the heart with two
    pacing leads. Most common type of pacemaker
    implanted today.

17
Single-chamber pacemaker
  • Correct a slow or unsteady heartbeat, resulted
    from heart block.
  • Pacemaker lead will ensure that the heart's
    ventricles contract rhythmically and fully.

A single-chamber pacemaker placed in the right
ventricle of the heart
18
Single-chamber pacemaker model available from
Medtronic
  • Rate responsive
  • It has one or two sensors that detect changes in
    the heart rate needs.
  • It then adjust the heart rate accordingly

Medtronic Kappa SR, Series 400
19
Dual-chamber pacemaker
  • Senses both atrial and ventricular activity to
    see if pacing is needed
  • When pacing does occur, the contraction of the
    atria is followed closely by a contraction in the
    ventricles
  • Resulting in timing that mimics the heart's
    natural way of working.

A dual-chamber pacemaker with two pacing leads
20
Dualchamber pacemaker model available from
Medtronic
  • Rate responsive
  • It has one or two sensors that detect changes in
    the heart rate needs.
  • It then adjust the heart rate accordingly

Medtronic Kappa DR, Series 400
21
Rate-Responsive Pacemaker
  • A rate-responsive pacemaker uses a or a
    combination of special sensor(s)
  • activity sensor
  • minute ventilation sensor
  • that recognizes body changes and helps the
    heartbeat speed up or slow down to meet patient
    body's changing needs for blood.
  • It mimics patient heart's natural function.
  • The physician has many options in programming the
    pacemaker to respond to the patient normal
    activities as illustrated in the next slide.

22
  • A normal heart rhythm slows down or speeds up
    many times during the day.
  • The heart beats slower while resting or sleeping.
  • Exercise or emotional excitement make heart beat
    faster because, in an excited state, the body
    requires greater amounts of blood to be
    circulated.

23
Successes of the Pacemaker
  • Successfully implanted, since the late 1950s.
  • More than 2 million people have been benefited
  • The development of new pacing technologies since
    1985 has opened the door for significant
    improvements in pacemaker wearers' quality of
    life
  • by permitting greater tolerance for exercise and
    participation in new activities.

24
Case study on the success of Medtronic Kappa 400
Series
  • One year after receiving a single sensor (minute
    ventilation), single chamber pacemaker, a
    69-year-old patient was still having symptoms
    when exercising
  • After implanting the Medtronic Kappa 400 Series
    pacemaker, the patient was able to resume his
    previous exercise regimen of rock climbing and
    exercising at a gym.
  • The integrated dual sensors (activity and minute
    ventilation) of the Medtronic Kappa 400 Series
    pacemakers provide heart rate support
    proportional to a patient's metabolic demands.

25
Pacemakers its future trend
  • In future generations,
  • developments in the field of microprocessor
    technology will most likely lead to greater
    flexibility in the self-adjustment of rate,
    output, and the overall sensitivity of
    pacemakers.
  • The continued innovation of programmability and
    telemetry will increase the diagnostic
    capabilities of pacemakers.
  • Systems are being developed which can facilitate
    storing of patient details and which can diagnose
    rhythm disturbances using sophisticated
    algorithms.
  • Sensors will be combined with electrogram
    analysis to differentiate between physiological
    and pathological alterations in hemodynamics so
    that appropriate adjustments can be initiated.

26
Pacemakers its future trend (cont.)
  • Pacemaker technology that is self-adjusting will
    evolve that can differentiate arrhythmias and
    initiate the appropriate pacing modality.
  • Progress in battery technology will reduce
    generator size further without effects on
    longevity.
  • Generator microprocessors will permit more
    flexible programming of algorithms that will
    satisfy the patient's changing requirements.
  • A pacemaker may be reprogrammed or experience a
    change in the sensing or pacing thresholds after
    a shock from a defibrillator.
  • In future generations, it is important that the
    pacemaker be able to protect itself from
    excessive energy and shocks caused by a
    defibrillator.

27
Comment and conclusion
  • A pacemaker system is a device that sends
    periodic impulses to the heart to restore the
    rhythm of the heart.
  • Early devices provided only single-chamber,
    asynchronous, nonprogrammable pacing coupled with
    questionable reliability and longevity.
  • Today, advanced electronics afford dual-chamber
    multiprogrammability, diagnostic functions, rate
    response, data collection, and exceptional
    reliability, and lithium-iodine power sources
    extend longevity to upward of 10 years.

28
Comment and conclusion (cont.)
  • Such features have evidently improved the
    management of patients with cardiac problems such
    as bradycardia.
  • The new diagnostic function can aid clinicians to
    diagnose and keep track with patients
    development.
  • Continual advances in a number of clinical,
    scientific, and engineering disciplines have so
    expanded the use of pacing that it now provides
    cost-effective benefits to an estimated 350,000
    patients worldwide each year.

29
Thats all for our presentation
  • Thank you very much for your
  • attention!
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