https://blog.wongcw.com/2021/12/08/%e5%9c%8b%e8%a1%8capple-watch%e7%b5%82%e6%96%bc%e7%8d%b2%e5%be%97%e3%80%8c%e5%ae%8c%e5%85%a8%e9%ab%94%e3%80%8d-ecg%e5%bf%83%e9%9b%bb%e5%9c%96%e5%b7%b2%e4%b8%8a%e7%b7%9a%e6%b8%ac%e8%a9%a6%e7%89%88/