1. Using Holter ECG and Heart Rate Variability to Detect Sleep-Disordered Breathing
Phyllis K Stein, Ph.D.
Heart Rate Variability Laboratory
Washington University School of Medicine
St. Louis, MO

2. Background
When patients with sleep-disordered breathing have an event, there is an autonomic arousal associated with a brief awakening, they then resume normal breathing, and fall back asleep.
This repeated awakening is associated with a repeated increase in heart rate which return to baseline when the patient falls back asleep.

3. Sleep Apnea Clarified

4. Heart-Rate-Based Graphical Method
for Detecting Sleep-Disordered Breathing
1. Sequence of unedited beat-to-beat R-R (or preferable edited N-N) intervals.
2. Convert R-R intervals to instantaneous HR (60,000/R-R interval in ms).
3. Plot tachogram of HR vs. time on 6 parallel 10-min plots (one hr/page).

5. Tachogram Axes x-axis = time in minutes (0-10 minutes)
0-100 bpm
“x-axis”
x-axis = time in minutes (0-10 minutes)
y-axis for each min plot is H (0-100 bpm in cm)
“x-axis” is mean HR for that min segment

6. Sleep Onset in a Patient Without OSAHS
To bed

7. Onset of OSAHS
Patient falls asleep

8. Tachograms From the Computers In Cardiology Sleep Apnea Contest
Data based on R-R intervals using simple QRS detection algorithm and not edited.
35 tachograms blindly scored for OSA, no OSA and indeterminate. # each category known.
Graphical method, 1 pair wrong, severe sleep-disordered breathing but hypopneas not OSA.

9. CVHR Subject 2
Brady-tachy pattern not seen

10. CVHR Subject 5
Tachycardia during OSA

11. CVHR Subject 7

12. CVHR Subject 8

13. CVHR and Normal Sleep or Quiet Rest Subject 9
Probable change in position resulting in OSA

14. CVHR Subject 13

15. CVHR Subject 16 (Hypopneas)

16. CVHR Subject 19

17. CVHR Subject 20

18. CVHR Subject 21

19. CVHR Subject 23

20. Apnea Appears to be Positional in Subject 23
Change in position terminates apnea

21. CVHR Subject 25

22. CVHR Subject 26

23. CVHR Subject 27

24. CVHR Subject 28

25. CVHR Subject 30
Probable change in position-apnea more severe earlier

26. Severe Sleep Apnea Subject 31
Magnitude of RSA declines during some but not all events

27. Severe Sleep Apnea Subject 32
Probable change in position or sleep stage. RSA is reduced.

28. Tachogram Evaluation
Identify epochs of CVHR (cyclic variation of heart rate)
Quantify CVHR by by total number of minutes (to nearest 30s) with CVHR.
If CVHR is predominant, no need to quantify.

29. CVHR Definition
At least 3 consecutive cycles of rising and falling heart rate.
A visible rise in heart rate (5 bpm).
A return to baseline.
Each cycle 10 s duration.
At least 20s but less than 2 min between cycles.

30. CVHR Criteria for Significantly Abnormal Sleep
20% of time in CVHR of any type
High amplitude regular CVHR pathomnemonic for OSA
Lower amplitude or irregular CVHR may be associated with apneas, hypopneas, periodic limb movements or arousals for no apparent reason.

31. Results of Sleep Lab Validation of CVHR Tachogram Method
100% detection of significantly abnormal sleep.
High amplitude regular CVHR always sleep apnea.
Lower amplitude or irregular CVHR could be apneas or hypopneas or leg movements, a mixture or arousals for no apparent reason.
Non-diagnostic for flat tachograms (extremely low HRV) or atrial fibrillation.

32. Heart Rate Patterns on Tachograms Can Detect More Than Just Sleep Apnea

33. HR Patterns During Central Apneas

34. HR Patterns During Severe De-Saturation
O2 Sat = 65%
Irregular Low Amplitude CVHR

35. Low Amplitude CVHR Possibly Associated with Mixed Events

36. HR Patterns Associated with Periodic Limb Movements

37. Cheyne-Stokes Breathing

38. Cheyne-Stokes Breathing

39. Blown Up Section of Prior Tachogram Showing RSA During Cheyne-Stokes Respiration

40. Power Spectral Analysis of Heart Rate Variability
to Detect Sleep-Disordered Breathing

41. HRV power spectral plot quantifies the underlying periodicities in heart rate.
CVHR is a periodic change in heart rate which should be reflected in the HRV power spectrum

42. Normal-Appearing Nighttime Power Spectral Plot
HF Peak Due to RSA

43. Onset of OSAHS
Patient falls asleep

44. Power Spectral Plot for Previous Tachogram
Showing OSAHS Pattern
VLF Peak Associated with Sleep Apnea
HF Peak Due to RSA
0.8 Hz

45. HR Patterns During Central Apneas

46. Power Spectral Plot for Previous Tachogram
Showing HRV Pattern for Central Apneas
0.8 Hz
VLF Peak Associated with Central Apneas
Little or no HF power

47. HR Patterns During Severe De-Saturation
O2 Sat =65%
Irregular Low Amplitude CVHR

48. Power Spectral Plot for Previous Tachogram
Diffuse HF Peak Reflecting Irregular
Respiration or Heart Rate Pattern
VLF Peak Associated with OSAHS
0.8 Hz

49. Cheyne-Stokes Breathing

50. 2-Min Averaged HRV Pattern for Cheyne-Stokes Respiration
Hard to see CSR peak

51. Hourly HRV Power Spectral Plots for Cheyne-Stokes Breathing

52. HR Patterns Associated with PLMs

53. Power Spectral Plot for Previous Tachogram
Showing Periodic Limb Movements
VLF Peak Due to PLMS (0.04 Hz)
HF Peak Due to RSA
0.8 Hz

54. Conclusions
Sleep apnea and other sleep-disturbing syndromes can easily be identified from heart rate tachograms generated from routine Holter recordings
Visual examination of HRV patterns generated from hourly power spectral plots often available on commercial Holter scanners may help identify patients with CVHR.
Method is not valid for patients with significant autonomic dysfunction resulting in flat tachograms or in patients with atrial fibrillation