A1 Refereed original research article in a scientific journal
Beat-to-beat cardiac repolarization lability increases during hypoxemia and arousals in obstructive sleep apnea patients
Authors: Ebrahimian Serajeddin, Sillanmäki Saara, Hietakoste Salla, Kulkas Antti, Töyräs Juha, Bailón Raquel, Hernando David, Lombardi Carolina, Grote Ludger, Bonsignore Maria R., Saaresranta Tarja, Pépin Jean-Louis, Leppänen Timo, Kainulainen Samu
Publisher: American Physiological Society
Publication year: 2024
Journal: American journal of physiology : heart and circulatory physiology
Journal name in source: American journal of physiology. Heart and circulatory physiology
Journal acronym: Am J Physiol Heart Circ Physiol
Volume: 326
Issue: 5
First page : H1094
Last page: H1104
ISSN: 0363-6135
eISSN: 1522-1539
DOI: https://doi.org/10.1152/ajpheart.00760.2023
Web address : https://journals.physiology.org/doi/full/10.1152/ajpheart.00760.2023
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/387706973
Obstructive sleep apnea (OSA) is associated with the progression of cardiovascular diseases, arrhythmias, and sudden cardiac death (SCD). However, the acute impacts of OSA and its consequences on heart function are not yet fully elucidated. We hypothesized that desaturation events acutely destabilize ventricular repolarization, and the presence of accompanying arousals magnifies this destabilization. Ventricular repolarization lability measures, comprising heart rate corrected QT (QTc), short-time-variability of QT (STVQT), and QT variability index (QTVI), were calculated before, during, and after 20,955 desaturations from lead II electrocardiography signals of 492 patients with suspected OSA (52% men). Variations in repolarization parameters were assessed during and after desaturations, both with and without accompanying arousals, and groupwise comparisons were performed based on desaturation duration and depth. Regression analyses were used to investigate the influence of confounding factors, comorbidities, and medications. The standard deviation (SD) of QT, mean QTc, SDQTc, and STVQT increased significantly (P < 0.01), whereas QTVI decreased (P < 0.01) during and after desaturations. The changes in SDQT, mean QTc, SDQTc, and QTVI were significantly amplified (P < 0.01) in the presence of accompanying arousals. Desaturation depth was an independent predictor of increased SDQTc (β = 0.405, P < 0.01), STVQT (β = 0.151, P < 0.01), and QTVI (β = 0.009, P < 0.01) during desaturation. Desaturations cause acute changes in ventricular repolarization, with deeper desaturations and accompanying arousals independently contributing to increased ventricular repolarization lability. This may partially explain the increased risk of arrhythmias and SCD in patients with OSA, especially when the OSA phenotype includes high hypoxic load and fragmented sleep.NEW & NOTEWORTHY Nocturnal desaturations are associated with increased ventricular repolarization lability. Deeper desaturations with accompanying arousals increase the magnitude of alterations, independent of confounding factors, comorbidities, and medications. Changes associated with desaturations can partially explain the increased risk of arrhythmias and sudden cardiac death in patients with OSA, especially in patients with high hypoxic load and fragmented sleep. This highlights the importance of detailed electrocardiogram analytics for patients with OSA.
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