Boston Scientific CRM training. module
1
basic pacing system - answerconsists of an implantable pulse generator and one or two
pacing leads
pacing lead - answerinsulated conductor wire that conducts sensed electrical signals
(electrogram) from the heart to the implanted PG and delivers pacing pulses to the heart
- one end of the lead (connector pin) connects to the pg and the other (lead tip) is in
contact with endocardial tissue
implantable pulse generator - answercontains a battery and the circuits that control
system operations
pacing lead - answerinsulated conductor wire that conducts sensed electrical signals
the PG and delivers pacing pulses to the heart
- battery and circuits are enclosed in a hermetically sealed titanium case
pacing circuit - answerconsists of a battery pacing lead, electrodes (cathode & anode),
and body tissues and fluid
pacing circuit battery - answerpower source that, along with the circuitry, generates
electrical impulses.
- electrical impulse begins in the pacemaker battery, travels along the lead to the
cathode, stimulates the heart, then returns through body tissue to the anode to
complete the pacing circuit
cathode (tip electrode) - answer- pacing lead conducts the impulse to the cathode
- cathode delivers the impulse to the myocardium
- negative electric charge
anode (ring electrode) - answerthe electrode to which the impulse returns after
stimulating the heart
- body tissues and fluid between the anode and cathode are part of the conduction
pathway
- positive electric charge
pacing pulse - answercurrent, voltage, and impedance
, pacing pulse: current (I) - answerthe movement of electrons through an electric circuit
over time, measured in milliamperes(mA) in a pacing circuit
pacing pulse: voltage (V) - answerthe force that causes current to flow
- in a pacing system, voltage is called amplitude, which reflects the intensity of the
pacing pulse
pacing pulse: impedance (R) - answersum of all factors that resist the flow of current
along a conduction pathway, measured in Ohms
- main sources of impedance in a pacing system are the lead conductor, lead electrode,
and the concentration of charged ions at the electrode-tissue interface
ohm's law - answerdescribes the relationship between current, voltage, and impedance
- shows that low voltage and high impedance reduce the battery current drain and
extend the pacemaker longevity
- decreasing the output voltage of a pacing system decreases the current flow
- increases the impedance of a pacing system decreases the current flow
- low voltage and high impedance reduce battery current drain and extend pacemaker
longevity
pacing impedance (resistance) - answer- affects the characteristics of a pacing pulse
and influences pacing efficiency
pacing impedance: electrode resistance - answerresistance to current flow from the
electrode to the myocardium
- concentrate the current and delivers a more intense pacing pulse
- electrode resistance uses current efficiency and therefor improves pacing efficiency
pacing impedance: lead conductor resistance - answer- resistance along the conductor
wire
- produces a small loss of energy to waste during impulse conduction
- does not contribute to myocardial stimulation and does not improve pacing efficiency
pacing impedance: polarization - answer- resistance caused by the concentration of
oppositely charged ions at the electrode
- ions form a barrier that resist current flow when the pacing pulse is delivered
- increases the voltage requirement, so it does not improve pacing efficiency
what do most pacemaker functions use for power? - answerlithium manganese dioxide
(Li/MNO2)
- pacemakers automatically monitor the status to estimate remaining battery life
- battery status is reported as a status indicator and time to explant gauge
- battery depletion is produced by measuring the battery capacity consumed, remaining
charge, and power consumption at current programmed settings
- voltage is NOT used to estimate battery depletion
- pacemaker battery longevity ranges from 8-15 years
1
basic pacing system - answerconsists of an implantable pulse generator and one or two
pacing leads
pacing lead - answerinsulated conductor wire that conducts sensed electrical signals
(electrogram) from the heart to the implanted PG and delivers pacing pulses to the heart
- one end of the lead (connector pin) connects to the pg and the other (lead tip) is in
contact with endocardial tissue
implantable pulse generator - answercontains a battery and the circuits that control
system operations
pacing lead - answerinsulated conductor wire that conducts sensed electrical signals
the PG and delivers pacing pulses to the heart
- battery and circuits are enclosed in a hermetically sealed titanium case
pacing circuit - answerconsists of a battery pacing lead, electrodes (cathode & anode),
and body tissues and fluid
pacing circuit battery - answerpower source that, along with the circuitry, generates
electrical impulses.
- electrical impulse begins in the pacemaker battery, travels along the lead to the
cathode, stimulates the heart, then returns through body tissue to the anode to
complete the pacing circuit
cathode (tip electrode) - answer- pacing lead conducts the impulse to the cathode
- cathode delivers the impulse to the myocardium
- negative electric charge
anode (ring electrode) - answerthe electrode to which the impulse returns after
stimulating the heart
- body tissues and fluid between the anode and cathode are part of the conduction
pathway
- positive electric charge
pacing pulse - answercurrent, voltage, and impedance
, pacing pulse: current (I) - answerthe movement of electrons through an electric circuit
over time, measured in milliamperes(mA) in a pacing circuit
pacing pulse: voltage (V) - answerthe force that causes current to flow
- in a pacing system, voltage is called amplitude, which reflects the intensity of the
pacing pulse
pacing pulse: impedance (R) - answersum of all factors that resist the flow of current
along a conduction pathway, measured in Ohms
- main sources of impedance in a pacing system are the lead conductor, lead electrode,
and the concentration of charged ions at the electrode-tissue interface
ohm's law - answerdescribes the relationship between current, voltage, and impedance
- shows that low voltage and high impedance reduce the battery current drain and
extend the pacemaker longevity
- decreasing the output voltage of a pacing system decreases the current flow
- increases the impedance of a pacing system decreases the current flow
- low voltage and high impedance reduce battery current drain and extend pacemaker
longevity
pacing impedance (resistance) - answer- affects the characteristics of a pacing pulse
and influences pacing efficiency
pacing impedance: electrode resistance - answerresistance to current flow from the
electrode to the myocardium
- concentrate the current and delivers a more intense pacing pulse
- electrode resistance uses current efficiency and therefor improves pacing efficiency
pacing impedance: lead conductor resistance - answer- resistance along the conductor
wire
- produces a small loss of energy to waste during impulse conduction
- does not contribute to myocardial stimulation and does not improve pacing efficiency
pacing impedance: polarization - answer- resistance caused by the concentration of
oppositely charged ions at the electrode
- ions form a barrier that resist current flow when the pacing pulse is delivered
- increases the voltage requirement, so it does not improve pacing efficiency
what do most pacemaker functions use for power? - answerlithium manganese dioxide
(Li/MNO2)
- pacemakers automatically monitor the status to estimate remaining battery life
- battery status is reported as a status indicator and time to explant gauge
- battery depletion is produced by measuring the battery capacity consumed, remaining
charge, and power consumption at current programmed settings
- voltage is NOT used to estimate battery depletion
- pacemaker battery longevity ranges from 8-15 years
