这个真的有用吗？

Apple Watch 是lz心脏病发作跌倒之后自动打急救电话用的。别的用处不大

显然不会有什么大用，心率不齐的应该会被记录下来，其他的也就算了。有一种专门手机用的所谓 EKG，比 Apple Watch 好点，但仍然无法和医院用的全套 EKG 比。

比Apple watch 好点？是说用在其它手机上？那怎么跟身体链接

就是测出偶尔心律不齐又怎样？

这里有篇 KridaMobil 和 Aplle Watch 4 比较的文章：

Conclusions

Both the AW4 and the KM could reliably detect rhythm and heart rate in real-life clinical situations. However, a nonsignificant trend occurred toward better rhythm detection and accuracy with KM, compared with AW4. The difference is mainly due to artifacts (eg, tremors) and the fit of the strap for AW4. The findings have important implications for how these consumer devices can be used in real-life clinical settings.

https://pmc.ncbi.nlm.nih.gov/articles/PMC9700214/