The Apple Watch already features a built-in heart rate monitor, however Apple is poised to improve this technology with an on-board electrocardiogram (EKG or ECG). Such a sensor would provide more detailed information regarding the electrical activity of the wearer's heart, potentially warning of irregular heart rates.
According to Bloomberg, adding this technology to Apple Watch would make it into a "serious medical device". With EKG capabilities, the Apple Watch would be able to detect heart conditions, which can increase the risk of strokes and heart failure.
Apple may have to seek FDA approval for such a sensor, as the wearable EKG would monitor the health of a user's heart and warn of potential cardiac problems. Apple is said to be developing a sensor that would work by taking heart measurements by squeezing the frame of the Apple Watch with two fingers. The device would then track the electrical signals in the heart without using any third-party EKG readers, such as the AliveCor KardiaBand.
Apple Watch has already been used to successfully track hypertension and sleep apnea. Apple has also expressed interest in monitoring blood glucose levels for those with diabetes. With Apple's push to develop more health functionality, a future Apple Watch could also provide more detailed heart monitoring with the push of a button.