Date: 14/10 2009
Student’s name: Mustafa Azmi Sami
Professor’s name: Professor Grigaliunas
To know the functions of a pacemaker and its use for medical purposes.
Task to be performed
To evaluate the main parameters of the cardiac pacemaker pulses: duration, frequency, voltage and period. Also to calculate battery lifetime of the pacemaker.
Many organs are being stimulated by electric pulses nowadays to restore lost or inadequate functions. Electric stimulation is often more effective than pharmacotherapy. When heart pulse rate becomes less than 40 per minute, than the natural pacemaker of the heart can be substituted by artificial periodic electrical pulses of a special generator. This generator sends out electrical pulses to the heart so it keeps pumping blood out lungs and body.
Equipment and materials
1. Connect the pacemaker to an oscilloscope and set the position to 0,05 V/cm and 0,2 ms/ cm. 2. Knob the level so the pulse appears on the screen of the oscilloscope. 3. Determine the duration and voltage of the pulse.
4. Take the amplitude of the pulse and multiply it by 50 (the real pulse is reduced 50 times). 5. Set knob “duration/cm” at position 100 ms/cm and adjust the knob so both of the pulses appear on the screen. 6. Take the period of the pulses, T.
7. Calculate heart beat frequency. f = 60/T.
8. Calculate the charge of each pulse. q = U*τ/R
9. Calculate battery life time. t = Q/ (q*365*24*60*f)
The methods we used for the calculations:
Measuring the amplitude [pic]
Measuring the duration of the pulse[pic]
• the amplitude is 5V
• the duration of the pulse is 0,00096 seconds
• the period between the two pulses in 0,92 seconds
• the frequency of the pulse is 1,08696 bps