2. Low Voltage Technology Stimulation and Sensing

3. Pacing

4. Pacemaker pulse Pulse-amplitude(Volt) Pulse width (ms)

5. To stimulate the heart...

6. Strength Duration Curve pulse amplitude [Volts] 2.0 1.0 pulse width [ms] 0 0.5 1.0 1.5

7. Strength Duration Curve Rheobase the minimum pulse amplitude at which capture results at an infinitely wide pulse duration (1.0 ms) Chronaxie the pulse duration for which the pulse amplitude is twice the rheobase (0.4 -0.6 ms)

8. 2 x Rheobase Rheobase Chronaxie Strength Duration Curve pulse amplitude [Volts] 2.0 1.0 pulse width [ms] 0 0.5 1.0 1.5

9. Fibrous tissue Fibrous tissue around the lead tip resulting in high threshold.(Low current density)

10. Classic Threshold Development over Time Threshold (Volts) Output Threshold 2 weeks 2-3 months Time Implantation

11. Today’s Threshold Development over Time Threshold (Volts) Output Threshold 2 weeks 2-3 months Time Implantation

12. Example of programmability Amplitude (V) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 Pulse width (ms) …0.4 0.6 0.8 1.0 1.1 1.2 1.4 1.5 0.5 0.7 0.9 1.3 0.05

13. Sensing

14. Electrical recordings SurfaceECG Cell- potential IEGM

15. Low frequency content High frequency content Signal Frequency Content Note that both have the same rate!

16. 0,2 mV 1 mV 8 mV The Band-Pass Filter T-wave P- or R-wave Myopotentials

17. Sensitivity10.0 mV Sensitivity5.0 mV Sensitivity 1.0 mV Choosing Sensitivity

18. Sensitivity, Atrial Channel P-wave~3 mV Atrial fibrillation ~0.2-1.0 mV Noise ~0.1 mV Sensitivity 0.3 mV 0.1 0.3 0.5 1.0 1.5 2.0 3.0 4.0 5.0 Sensitivity 1.5 mV

19. Sensitivity, Ventricular Channel R-wave~9 mV PVC ~3.5 mV Noise ~0.5 mV Sensitivity 2.0 mV 0.5 1.0 2.0 3.0 4.0 5.0 7.0 9.0 12.5 Sensitivity 4.5 mV

20. Depolarisation spread/ sensing points B A Point A D Point C C Point B Point D C D A B