Apple has patented a new emergency system for Apple Watch what could send an alert to friends or family when it is detected that the user requires medical care. It is able to monitor the pulsations to detect Heart problems, and much more.
The patent entitled "CARE EVENT DETECTION AND ALERTS" describes a system that monitors an Apple Watch user for so-called "attention events", or any scenario that might require the attention of the user. medical staff, Firefighters, policemen, or other emergency services.
For example the device could be programmed to monitor the heart of an arrhythmia user, for after detection, send an alert to the response to the family or emergencies. While not specifically mentioned in the document, the Apple Watch is the only one qualified to meet the goals of the proposed system.
That is because the Apple Watch is already equipped with advanced sensors, and a processing hardware that is capable of detecting these processes. You can also communicate with the iPhone to make sure none of the alerts are missed.
In some cases the iPhone and Apple Watch will work together to detect these attention events. For example, if the iPhone detects a change in acceleration or elevation, and the watch detects significant changes in heart rate, this could suggest to the user that it requires urgent attention. You may also be able to send useful information with said alert, such as a user's medical data obtained in the Health application, their location, and much more.
In this link we leave you the patent of the emergency system for the Apple Watch.