Machines · Study 077
ECG Monitor
A bedside heart monitor sweeps a green ECG trace across a grid. Raise or lower the heart rate from 45 to 160 beats per minute with your pointer.
What you're looking at
The waveform is a sum of five bell shaped bumps placed at fixed points in each beat: a small P wave, the sharp down-up-down of the QRS complex, and a broader T wave. A write head moves left to right laying down the newest samples and erasing a short gap ahead of itself, as older monitors did.
The idea behind it
The letters P, Q, R, S and T were chosen by Willem Einthoven, who built the first practical electrocardiograph in the early 1900s and received a Nobel Prize for it in 1924. Each wave marks an electrical event: the P wave is the upper chambers firing, the QRS spike is the main pumping chambers, and the T wave is their recovery.
Try this
Move the pointer up to speed the heart and down to slow it. This is an illustration, not a medical reference.
