Later this year, the ECG app will be available to Apple Watch Series 4 customers in the US, giving them the ability to take an electric cardiogram anytime, right from their wrist. And for US customers with Apple Watch Series 1 and later watchOS will soon enable periodic checks for a regular heart rhythms that may be suggestive of AFib. These are unprecedented and potentially life-changing features, showing how Apple Watch is not only an indispensable communication and fitness companion but also an intelligent guardian for your health.