Discrepancy between bpm in Kardia mobile and Fitbit

[star68]

Hi,

I have a Kardia mobile (a device to measure your heart like an ecg) that I purchased with the intention to record my tachycardia episodes to show my cardiologist.  If any of you have this device perhaps you could answer my question.  An episode woke me up last night and I quickly got the Kardia to record it, the Kardia was saying poor signal but the bpm read 150 the signal was on and off, so I don't know if that affect the heart beat recording but in my fitbit heart rest section shows that the highest recorded heartbeat at the same time of the episode is 107 bpm.  I am very confused.  As well when my episode started I felt fast hearbeat but the fitbit only showed like 85 bpm it feels like when it's a sudden fast heartbeat it freezes.  Have you ever experienced this? Thank you.

[SunsetRunner]

My Fitbit ( Ionic ) is always way off and can't handle the faster or rapidly changing HR. I tested it many times against chest strap ( also ECG ). I wouldn't use Fitbit or any other optical HR sensor as a reference device in case of medical condition. It isn't just Fitbit. Optical sensors are far from being perfect. Even when using pulseoximeter which is little more medical device than a fitness tracker, the test should be done several times including different fingers and the person should be still to obtain best results (still not ruling out further ECG examination).

[emili]

@star68 I would not use your fitbit as a medical device, not in any way. It is meant for tracking activity which if its wrong doesn't typically result in a medical emergency.