Why I returned my KardiaMobile 6L ECG device
July 06, 2025
A key feature of the Apple Watch is that it provides passive monitoring of your heart, and it can alert you to a certain cardiac rhythm issues. But it’s a “one lead” ECG, which is a fraction (1/12th, to be exact) of a professional device. This limits how many conditions the Apple Watch can detect.
As a supplement to the Apple Watch, I decided to buy a KardiaMobile 6L ECG device. With its additional sensors, it promised to give more detailed readings. The Kardia devices, including their less expensive models, only monitor your heart when you’re seated and using them, which is why I’m calling them supplemental.
After coughing up $140 to Amazon for the Kardia Mobile 6L, I returned it for a refund after just a couple of days. I’m a tech professional, and I carefully research my purchases, and I found The KardiaMobile 6L had too many unpleasant surprises and limitations.
Here are the ones that bothered me the most:
- To see the more advanced analysis, you have to subscribe at the cost of $100 a year. Without a subscription, it doesn’t do anything more than the Apple Watch. (Technically, it actually does less.)
- The Kardia app constantly nags you to subscribe by implying that the app has identified serious conditions, but won’t tell you about them until you pay up. As I declined to subscribe, I don’t know if it really had detected something or not, but if it does and won’t tell you without payment, that’s extortion.
- Your ECG data is locked inside the Kardia app. You can only share a rendered PDF of the tracing, and the data is not written to HealthKit so other useful apps and services, such as Qaly, can’t read it.
- The Kardia app requires you to log in every time you use it, and it does not support Password Manager. This is a serious usability problem. If this is supposed to be a ‘privacy’ feature, other apps have solved this problem in a more user-friendly way.
None of these issues were apparent before I purchased the KardiaMobile 6L device. In fact, the reviews posted by others are overwhelmingly positive. But those customers probably lack a comparative experience and don’t realize how unfriendly, limited, and imperious the product is.