1. Figure 13.1 Block diagram of an asynchronous cardiac pacemaker

2. Figure Two of the more commonly applied cardiac pacemaker electrodes (a) Bipolar intraluminal electrode. (b) Intramyocardial electrode.

3. Figure A demand-type synchronous pacemaker Electrodes serve as a means of both applying the stimulus pulse and detecting the electric signal from spontaneously occurring ventricular contractions that are used to inhibit the pacemaker's timing circuit.

4. Figure An atrial-synchronous cardiac pacemaker, which detects electric signals corresponding to the contraction of the atria and uses appropriate delays to activate a stimulus pulse to the ventricles. Figure 13.5 shows the waveforms corresponding to the voltages noted.

5. Figure 13.5 Block diagram of a rate-responsive pacemaker

6. Figure A transcutaneous RF-powered electric stimulator Note that the implanted circuit of this stimulator is entirely passive and that the amplitude of the pulse supplied to the electrodes is dependent on the coupling coefficient between the internal and external coils.

7. Figure A stimulator system for use on stroke patients suffering from gait problems associated with drop foot.

8. Figure 13.8 Block diagram of cochlear prosthesis
Speech
processor
Stimulus
controller
External
coil
Internal
coil
Stimulator
circuit
Electrode
array
Microphone
External unit
Implanted unit
Figure 13.8 Block diagram of cochlear prosthesis

9. Figure (a) Basic circuit diagram for a capacitive–discharge type of cardiac defibrillator. (b) A typical waveform of the discharge pulse. The actual waveshape is strongly dependent on the values of L, C, and the torso resistance RL.

10. Figure Electrodes used in cardiac defibrillation (a) A spoon-shaped internal electrode that is applied directly to the heart. (b) A paddle-type electrode that is applied against the anterior chest wall.

11. Figure A cardioverter The defibrillation pulse in this case must be synchronized with the R wave of the ECG so that it is applied to a patient shortly after the occurrence of the R wave.

12. Figure Connection of a pump oxygenator to bypass the heart A disk-type oxygenator is used with a roller pump. Venous blood is taken from a cannula in the right atrium, and oxygenated blood is returned through a cannula in the femoral artery.

13. Figure An artificial kidney The dialysate delivery system in this unit mixes dialysate from a concentrate before pumping it through the exchange chamber.

14. Figure In extracorporeal shock-wave lithotripsy, a biplane x-ray apparatus is used to make sure the stone is at the focal point of spark-generated shock waves from the ellipsoidal reflector.

15. Figure An instrumentation system for recording pressure, temperature, and percentage of O2 in inspired air coming from a continuous-positive-airway-pressure apparatus.

16. Thermistor
Power
line
Bridge
Amplifier 1 3
Gate
pulse
generator 4
Silicon-
controlled
switch
Comparator
Set-point
resistor
1-Hz
sawtooth
generator 2 5
Heater
Figure Block diagram of a proportional temperature controller used to maintain the temperature of air inside an infant incubator.

17. Figure 13.17 Block diagram of the electronic control system for a fluid or drug delivery pump

18. Power supply Electronic controller Sensor Control valve Reservoir Pump
To tissue
Figure A block diagram of an implantable artificial pancreas showing the major components of the system.

19. Figure 13. 19 (a) Block diagram for an electrosurgical unit
Figure (a) Block diagram for an electrosurgical unit. High-power, high-frequency oscillating currents are generated and coupled to electrodes to incise and coagulate tissue. (b) Three different electric voltage waveforms available at the output of electrosurgical units for carrying out different functions.

20. Figure 13.20 Block diagram of a typical electrosurgical unit