Samsung had patented a "laser speckle interferometric system" technology which has been earlier seen in the 2016 patents. The devices also included in this are Galaxy smartphones and tablets and Galaxy Gear.
According to the report in Patently Mobile, "The laser speckle interferometric system may be applied to a mobile device of a cuff type to be worn on an arm of the user. For example, the laser speckle interferometric system according to an exemplary embodiment may be used when a brachial artery is used for measurement and correction of vital signs such as the blood pressure and heart rate."
The trademark filing doesn't reveal much information about where and on what device this technology has been used or will be used, but it is speculated to be included on a smartwatch.
The Apple watch uses the optical heart-rate sensor technology which measures your heart-rate and helps you to calm down.
The rumoured Samsung Galaxy watch is also alleged to be based on recent trademarks.