One of the biggest surprises at this year's September event was the Apple Watch Series 4, and more specifically its ability to take electrocardiograms (or ECGs) on the go. A truly revolutionary feature that allows users to get a super-accurate heart reading by simply touching the Digital Crown of the Apple Watch Series 4. This is the first smartwatch to offer this type of functionality, but Apple went further to clarify that the Series 4 was also the first over-the-counter ECG device for consumers.