What does a Kardia Mobile ECG tell my cardiologist that a wearable can't?

The AliveCor Kardia Mobile is an FDA-cleared, consumer-accessible single-lead ECG device, you press your thumbs (or your knee) against the electrodes for 30 seconds and receive an ECG trace stored in the Kardia app. It is meaningfully superior to the passive rhythm notifications generated by consumer wearables for one specific purpose: it generates an actual ECG trace that a physician can read, not an algorithmic interpretation without the underlying data.

What your cardiologist can see on a Kardia trace that a passive wearable alert does not provide: the actual morphology of P waves (confirming or denying AFib), the pattern of premature beats (distinguishing PACs from PVCs from artifact), the QRS duration (a prolonged QRS suggests bundle branch block), and the regularity pattern that differentiates atrial flutter from AFib. What neither a Kardia nor an Apple Watch single-lead ECG can tell me: ST-segment depression (because the standard limb leads measuring ischemia require a different axis than these devices provide), left ventricular hypertrophy, Q-wave patterns, or the full picture of a 12-lead ECG. A Kardia is a very useful clinical tool for rhythm documentation. It is not a 12-lead ECG. (AliveCor Kardia FDA clearance, https://www.accessdata.fda.gov/cdrh_docs/pdf16/K163724.pdf)

Cardiologist's calibrated position, Promising (2) for Kardia as a clinical supplement for rhythm documentation. Not a substitute for formal cardiac evaluation.

What to do: If you are having palpitations, bring a Kardia to your appointment and record a trace during the visit. If you cannot capture a trace during an episode, record at least three baseline readings to establish your normal rhythm pattern.

For the full picture, read What Your Apple Watch Is Trying to Tell You.