10- Pacemakers Flashcards
What is the role of the pacemaker ?
Supports the heart and circulatory system
Site the date of the fort portable pacemaker and it’s évolution till nowadays
1958: first portable pacemaker
2004: implantable pacemaker
Site the typical system components for pacemakers
Leads/electrodes
Pacemaker device
External computer for programming
Site the main part of the circuitry of a pacemaker
impulse generator
electrode for stimulation
return electrode
heart (tissue resistance)
which part of the circuitry generate the pulse ?
The capacitor.
how to create a pulse
generate a stimulation
delay
bring capacitor in
discharge the capacitor
what are the aims of the circuit of a parcemaker ?
create a biphasic pulse
charge accumulation ensures proper charge compensation
what are the key parameters
electrodes size ranges of impedance tissue resistance (loss voltages)
what are the five main parameers of pacemaker code in the right order ?
chamber paced (A,V,D) - chamber sensed (A,V,D) - response to sensing (I,T,D) - programmability rate to modulation (P, M, C, R) - antiarrhythmia function (P,S,D)
How to hermeticaly seal pacemakers ?
titanium and electril feedthrough
how are pin connectors in pacemaker ?
made of plastic, connector with clamp.
Cite the electronic components of pacemakers
Coil, battery(5-10y), electronics, IC packaging (ASICs, hybrid), subtrate (ceramic, FR4 captor)
Cite the implant electronics components
pulse generator (capacitor), signal detection(ECG), signal processing (ecg analysis) and communication (coil)
site advantage of unipolar field stimulation
simple concept, low space requirement
Site advantage of bipolar field stimulation
less susceptible to interference, more complex to manufacture.
Describe the implantation of pacemaker
leads: transvenous, fena subelavia dextra (if right ventricle via vena cava if left, in right atrum via coronary artery).
stimulator in skin/muscle.
Site two example of wireless pacemakers
Nanostim(st jude medical) or micra(medtronic)
Defines the three pacing and sensory functions
Fixed frequency (stimulator in right ventricle)
P wave triggered ( sensed in A , paced in V)
R wave controlled (paced and sensed in V)
When is done atrial stimulation ?
1 before Pwave
cite 3 pacemakers mode
A sensing, V pacing
V sensing, A pacing
A and V pacing (before P, and anorther time)
which parameter can be chosen for the stimulation ?
impulse amplitude and duration, sensitivity, interval for trigger (time between detected heart signal and stimulation) and conduction (time between stimulation and activation)
how are sensors integratted in pacemakers ?
receive from heart and disturbance inf, send to pacemaker.
what is the sick sine syndrom (SSS) ?
Information for frequency is missing.
What are the limit for control in pacemaker ?
Open loop control and no inf about hemodynamic needs.
what amount of energy has to be given for defibrillator ?
3 J:Kg. so from 200 to 400J at 2A for 10-20
what is called AED ?
Automated External Defibrillator (def. after ECG measurement)
how does defibrillators works ?
defibrillation of the atria - triggering from R wave.
what are the main actors in circuit for defibrillation.
capacitor to discharge
coil to smooth peaks
How does the semi automated defibrilator works ?
USer delivers the discharge
