http://cnet.co/TDeZl2
Several fitness trackers, as well as the Samsung Galaxy S5, now boast the ability to measure your heart rate. How do their readings stack up to an EKG? CNET’s Sharon Profis with help from Kaiser Permanente cardiologist Dr. Jon Zaroff put the Garmin VivoFit, Withings Pulse O2, Basis Carbon Steel, Samsung Gear Fit, and Samsung Galaxy S5 to the test.

source