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Sleep Circulation Time from Pulse Oximetry and Polysomnography: Predictive Value in Patients with Heart Failure with
Wei Jung Hsia1, Jack Rodman2, Benjamin Cantrill1
1Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90023, USA.
Sensors (Basel, Switzerland)
|August 13, 2026
Summary
Circulation time (Tcirc) measured during polysomnography (PSG) can help identify poor cardiac function in sleep apnea patients. A Tcirc over 28.6 seconds is linked to reduced ejection fraction (EF).
Area of Science:
- Cardiology
- Sleep Medicine
- Medical Diagnostics
Background:
- Assessing cardiac function, particularly left ventricular ejection fraction (EF), is crucial in managing patients with sleep apnea.
- Polysomnography (PSG) with pulse oximetry offers a potential non-invasive method to evaluate physiological parameters during sleep.
Purpose of the Study:
- To evaluate the utility of circulation time (Tcirc) derived from PSG in identifying patients with reduced EF.
- To determine if Tcirc can serve as a biomarker for poor cardiac function in individuals with sleep apnea.
Main Methods:
- Retrospective analysis of 89 adult sleep apnea patients (AHI > 5/h) who underwent PSG and transthoracic echocardiography (TTE) within one year.
- Calculation and averaging of Tcirc for each sleep stage (N2, N3, REM) from PSG data.
- Statistical analysis including Wilcoxon rank sum test, logistic regression, and Youden index to correlate Tcirc with EF.
Main Results:
- 14 patients had low EF (≤45%, Group A) and 75 had normal EF (≥50%, Group B).
- Group A exhibited prolonged overall Tcirc (median 27.8s) compared to Group B (median 23.5s), though not statistically significant (p=0.311).
- An optimal Tcirc cut-point of 28.6s demonstrated moderate discrimination (AUC=0.6), with Tcirc ≥ 28.6s associated with a 2.56-fold increased likelihood of low EF.
Conclusions:
- Total sleep Tcirc exceeding 28.6 seconds is associated with low ejection fraction in sleep apnea patients.
- This Tcirc threshold shows a specificity of 0.78 for identifying reduced EF, suggesting its potential as a screening tool.
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