attached contacts to obtain
the clearest waveforms.
generated by the heart when
it is beating can indicate many things. First, the distance
(time) between beats indicates the rate the heart is beating.
For example, if the time between beats is .75 seconds, the
heart rate is 80 beats per minute, BPM, calculated by the
formula, BPM = 60/time) = 60/.75 = 80. For .428 seconds,
the BPM = 60/.428 = 140 BPM.
Other things like uneven beats (arrhythmias) show up as
varied spacing between beats. This happens very often in
older people (like myself). Inverted “T” waves may indicate
potassium levels that are too low or ischemia (restricted
blood flow) due to arterial plaques or blockages.
Other waveform anomalies can indicate damaged heart
tissue, electrolyte imbalances, ectopic firing, atrial or
ventricle fibrillation, etc. It is left to the reader to consult
with a health care professional or cardiologist if they feel
something is abnormal.
There are many texts available for understanding and
interpreting ECG waveforms. Here are some for you to
• www.merckmanuals.com/professional/cardio vascular-disorders/cardiovascular-tests-and-procedures/electrocardiography-ecg
Conclusion and Final
The unit worked beautifully when I tested it on myself,
my wife, and friends. The tracings were clear and detailed.
Some of the recordings I captured and saved are shown in
Figures 17 and 18.
I have included the actual trace recordings which can be
downloaded from the article link. If readers have any
questions, you may contact me at RJHEE@aol.com. NV
February 2017 31
■ FIGURE 17. My ECG waveform.
■ FIGURE 18. My wife’s ECG waveform.
■ FIGURE 15. Lead II
■ FIGURE 16.