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Low Voltage Technology. Stimulation and Sensing. Pacing. Pacemaker pulse. Pulse- amplitude (Volt). Pulse width (ms). To stimulate the heart. Strength Duration Curve. pulse amplitude [Volts]. 2.0. 1.0. pulse width [ms]. 0. 0.5. 1.0. 1.5. Strength Duration Curve. Rheobase
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Low Voltage Technology Stimulation and Sensing
Pacemaker pulse Pulse-amplitude(Volt) Pulse width (ms)
Strength Duration Curve pulse amplitude [Volts] 2.0 1.0 pulse width [ms] 0 0.5 1.0 1.5
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)
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
Fibrous tissue Fibrous tissue around the lead tip resulting in high threshold.(Low current density)
Classic Threshold Development over Time Threshold (Volts) Output Threshold 2 weeks 2-3 months Time Implantation
Today’s Threshold Development over Time Threshold (Volts) Output Threshold 2 weeks 2-3 months Time Implantation
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
Electrical recordings SurfaceECG Cell- potential IEGM
Low frequency content High frequency content Signal Frequency Content Note that both have the same rate!
0,2 mV 1 mV 8 mV The Band-Pass Filter T-wave P- or R-wave Myopotentials
Sensitivity10.0 mV Sensitivity5.0 mV Sensitivity 1.0 mV Choosing Sensitivity
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
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
Depolarisation spread/ sensing points B A Point A D Point C C Point B Point D C D A B