1. CARDIAC PACEMAKER
Ms. Saranya N
27-Feb-18
Cardiac Pacemaker

2. Implantable Pacemaker Systems Contain the Following Components:
Lead wire(s)
Implantable pulse generator (IPG)
A basic pacing system is made up of:
Implantable pulse generator that contains:
A power source—the battery within the pulse generator that generates the impulse
Circuitry—controls pacemaker operations
Leads—Insulated wires that deliver electrical impulses from the pulse generator to the heart. Leads also transmit electrical signals from the heart to the pulse generator.
Electrode—a conductor located at the end of the lead; delivers the impulse to the heart.
27-Feb-18
Cardiac Pacemaker

3. Pacemaker Components Combine with Body Tissue to Form a Complete Circuit
Pulse generator: power source or battery
Leads or wires
Cathode (negative electrode)
Anode (positive electrode)
Body tissue
Lead
IPG
In a bipolar system, body tissue is part of the circuit only in the sense that it affects impedance (at the electrode-tissue interface). In a unipolar system, contact with body tissue is essential to ground the IPG and allow pacing to occur.
Anode
Cathode
27-Feb-18
Cardiac Pacemaker

4. The Pulse Generator:
Contains a battery that provides the energy for sending electrical impulses to the heart
Houses the circuitry that controls pacemaker operations
Circuitry
Lithium-iodine is the most commonly used power source for today’s pacemakers. Microprocessors (both ROM and RAM) control sensing, output, telemetry, and diagnostic circuits.
Battery
27-Feb-18
Cardiac Pacemaker

5. Leads Are Insulated Wires That:
Deliver electrical impulses from the pulse generator to the heart
Sense cardiac depolarization
Lead
27-Feb-18
Cardiac Pacemaker

6. During Pacing, the Impulse:
Impulse onset
Begins in the pulse generator
Flows through the lead and the cathode (–)
Stimulates the heart
Returns to the anode (+) *
During pacing, the electrical impulse:
Begins in the pulse generator
Flows through the cathode (negative electrode)
Stimulates the heart tissue
Returns through the body tissue to the anode (positive electrode)
This pathway forms a complete pacing circuit.
27-Feb-18
Cardiac Pacemaker

7. Flows through the tip electrode (cathode)
A Unipolar Pacing System Contains a Lead with Only One Electrode Within the Heart; In This System, the Impulse:
Flows through the tip electrode (cathode)
Stimulates the heart
Returns through body fluid and tissue to the IPG (anode) +
Anode
In the unipolar system, the impulse:
Travels down the lead wire to stimulate the heart at the tip electrode also referred to as the cathode (–)
Returns to the metal casing of the impulse generator or the anode (+) by way of body fluids
The flow of the impulse makes a complete circuit. -
Cathode
27-Feb-18
Cardiac Pacemaker

8. Flows through the tip electrode located at the end of the lead wire
A Bipolar Pacing System Contains a Lead with Two Electrodes Within the Heart. In This System, the Impulse:
Flows through the tip electrode located at the end of the lead wire
Stimulates the heart
Returns to the ring electrode above the lead tip
The impulse:
Travels down the lead wire to stimulate the heart at the tip electrode, which is the cathode (–)
Travels to the ring electrode, which is the anode (+), located several inches above the lead tip
Returns to the pulse generator by way of the lead wire
Anode
Cathode
27-Feb-18
Cardiac Pacemaker

9. Most Pacemakers Perform Four Functions:
Stimulate cardiac depolarization
Sense intrinsic cardiac function
Respond to increased metabolic demand by providing rate responsive pacing
Provide diagnostic information stored by the pacemaker
The modern pacemaker supports heart function in the following ways:
Provides effective and consistent cardiac depolarization
Prevents unnecessary pacing by sensing cardiac activity
Increases rate to meet increased metabolic demand
Provides information about how the patient’s heart and the implanted pacemaker are functioning
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Cardiac Pacemaker

10. Types 1. Asynchronous/Fixed Rate 2. Synchronous/Demand
3. Single/Dual Chamber
Sequential (A & V)
4. Programmable/nonprogrammable
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Cardiac Pacemaker

11. Single-Chamber System
The pacing lead is implanted in the atrium or ventricle, depending on the chamber to be paced and sensed
27-Feb-18
Cardiac Pacemaker

12. Advantages and Disadvantages of Single-Chamber Pacing Systems
Implantation of a single lead
Single ventricular lead does not provide AV synchrony
Single atrial lead does not provide ventricular backup if A-to-V conduction is lost
Pacing in the VVI/R mode and loss of AV synchrony can lead to pacemaker syndrome. Pacemaker syndrome can be defined as “an assortment of symptoms related to the adverse hemodynamic impact from the loss of AV synchrony.”
Atrial pacemakers should only be used with patients who have proven AV conduction and regular follow-up testing available.
27-Feb-18
Cardiac Pacemaker

13. Dual-Chamber Systems Have Two Leads:
One lead implanted in the atrium
One lead implanted in the ventricle
27-Feb-18
Cardiac Pacemaker

14. Benefits of Dual Chamber Pacing
Provides AV synchrony
Lower incidence of atrial fibrillation
Lower risk of systemic embolism and stroke
Lower incidence of new congestive heart failure
Lower mortality and higher survival rates
Studies have been done that demonstrate the differences in outcome, hemodynamic improvement, and quality of life assessment by using AV synchronous, or "atrial-based," pacing modes instead of VVI/R. Some of the benefits of using an atrial-based pacing mode include:
AV synchrony–Clinical benefits such as increased cardiac output, augmentation of ventricular filling (especially important for the majority of the pacing population with LVD and reduced compliance from effects of aging). Providing AV synchrony minimizes valvular regurgitation, and preserves atrial electrical stability.
In the Framingham Study, the development of chronic AF was associated with a doubling of overall mortality and of mortality from cardiovascular disease (Kannel, 1982) The following emphasize the importance of preventing atrial fibrillation:
Patients with AF unrelated to rheumatic or prosthetic valvular disease have a risk of ischemic stroke about five times higher than those with normal sinus rhythm.
AF is associated with over 75,000 cases of stroke per year.
See bibliography for listing of studies cited.
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Cardiac Pacemaker

15. PACEMAKER MODE?
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Cardiac Pacemaker

16. PACEMAKER MODE?
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Cardiac Pacemaker

17. PACEMAKER MODE?
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Cardiac Pacemaker

18. WHAT IS HAPPENING HERE?
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Cardiac Pacemaker

19. WHAT IS HAPPENING HERE?
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Cardiac Pacemaker

20. THANK YOU
27-Feb-18
Cardiac Pacemaker