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Fitbit ECG Data Export Format

The Fitbit Electrocardiogram (ECG) data export reports a participant’s ECG reading taken from their Fitbit wearable device. The Fitbit ECG app allows participants to create and record an ECG by taking a 30-second reading on their wrist-worn Fitbit device. This is made possible by the electrical sensors on certain Fitbit products that can detect and analyze heart rhythm data for signs of atrial fibrillation (AFib). While the assessment cannot provide a definitive diagnosis of AFib, the results can lead to a more productive conversation between a participant and their healthcare provider.

The data in the Fitbit export is obtained through the Fitbit API. The available data will vary based on the device capabilities and the user's privacy settings. See the Fitbit "Electrocardiogram (ECG)" documentation for more information about using and interpreting Fitbit data.

Fitbit ECG

Fitbit ECG Waveform

Sample CSV Exports

In the CSV export, the waveform sample data is exported in a separate file from the ECG reading data.

FitbitECG:

FitbitEcgKey,ParticipantID,ParticipantIdentifier,InsertedDate,StartTime,AverageHeartrate,ResultClassification,SamplingFrequencyHz,ScalingFactor,NumberOfWaveformSamples,LeadNumber,FeatureVersion,DeviceName,FirmwareVersion
7e6135ff4edeed11a1789ccd120ce8c9-1862dbf0ad0,7e6135ff-4ede-ed11-a178-9ccd120ce8c9,aaf84dbd-4ede-ed11-a178-9ccd120ce8c9,2023-04-21T19:14:00Z,2023-02-07T16:19:00.304,49,Inconclusive: Low heart rate,250,10922,7500,1,2.11.0-2.13-2.16,Sense 2,20001.184.52

FitbitECG_Waveform:

FitbitEcgKey,Index,WaveformSample
7e6135ff4edeed11a1789ccd120ce8c9-1862dbf0ad0,0,0
7e6135ff4edeed11a1789ccd120ce8c9-1862dbf0ad0,1,11593
7e6135ff4edeed11a1789ccd120ce8c9-1862dbf0ad0,2,23106
7e6135ff4edeed11a1789ccd120ce8c9-1862dbf0ad0,3,32767

Sample JSON Export

ECG & Waveforms:

{
 "FitbitEcgKey": "7e6135ff4edeed11a1789ccd120ce8c9-1862dbf0ad0",
 "StartTime": "2023-02-07T16:19:00.304",
 "AverageHeartRate": 49,
 "ResultClassification": "Inconclusive: Low heart rate",
 "WaveformSamples": [
  0,
  11593,
  23106,
  32767,
  ...
  ],
 "SamplingFrequencyHz": 250.0,
 "ScalingFactor": 10922.0,
 "NumberOfWaveformSamples": 7500,
 "LeadNumber": 1,
 "FeatureVersion": "2.11.0-2.13-2.16",
 "DeviceName": "Sense 2",
 "FirmwareVersion": "20001.184.52",
 "ParticipantID": "7e6135ff-4ede-ed11-a178-9ccd120ce8c9",
 "ParticipantIdentifier": "aaf84dbd-4ede-ed11-a178-9ccd120ce8c9",
 "InsertedDate": "2023-04-21T19:14:00Z"
}