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Definition of measures for the study of heart rate variability in the time domain(7)
|
Measure |
Unit | Definition |
|---|---|---|
| SDNN | ms | Standard deviation of all normal NN intervals |
| SDNNi | ms | Standard deviation of NN calculated over 5-minute intervals |
| SDANN | ms | Standard deviation of the average NN interval |
| rMSSD | ms | Root mean square of the successive NN interval difference |
| pNN50 | % | Normal-to-normal NN intervals whose difference exceeds 50 milliseconds |
