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Ebrahimian S, Sillanmäki S, Hietakoste S, Kulkas A, Töyräs J, Bailón R, Hernando D, Lombardi C, Grote L, Bonsignore MR, Saaresranta T, Pépin JL, Leppänen T, Kainulainen S. Beat-to-beat cardiac repolarization lability increases during hypoxemia and arousals in obstructive sleep apnea patients. Am J Physiol Heart Circ Physiol 2024; 326:H1094-H1104. [PMID: 38426864 DOI: 10.1152/ajpheart.00760.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/02/2024]
Abstract
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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Affiliation(s)
- Serajeddin Ebrahimian
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Saara Sillanmäki
- Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Salla Hietakoste
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Antti Kulkas
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- Department of Clinical Neurophysiology, Seinäjoki Central Hospital, Seinäjoki, Finland
| | - Juha Töyräs
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane, Australia
- Science Service Center, Kuopio University Hospital, Kuopio, Finland
| | - Raquel Bailón
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragón Institute of Engineering Research (I3A), IIS Aragón, University of Zaragoza, Zaragoza, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - David Hernando
- Biomedical Signal Interpretation and Computational Simulation (BSICoS) Group, Aragón Institute of Engineering Research (I3A), IIS Aragón, University of Zaragoza, Zaragoza, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Madrid, Spain
| | - Carolina Lombardi
- IRCCS Istituto Auxologico Italiano, Department of Cardiovascular, Neural and Metabolic Sciences, Milan, Italy
- Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Ludger Grote
- Department of Sleep Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
- Sleep and Vigilance Laboratory, Department of Internal Medicine, University of Gothenburg, Gothenburg, Sweden
| | | | - Tarja Saaresranta
- Division of Medicine, Department of Pulmonary Diseases, Turku University Hospital, University of Turku, Turku, Finland
- Sleep Research Centre, Department of Pulmonary Diseases and Clinical Allergology, University of Turku, Turku, Finland
| | - Jean-Louis Pépin
- Inserm U1300, HP2 Laboratory, University of Grenoble Alpes, Grenoble, France
| | - Timo Leppänen
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane, Australia
| | - Samu Kainulainen
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
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Toman O, Hnatkova K, Šišáková M, Smetana P, Huster KM, Barthel P, Novotný T, Andršová I, Schmidt G, Malik M. Short-Term Beat-to-Beat QT Variability Appears Influenced More Strongly by Recording Quality Than by Beat-to-Beat RR Variability. Front Physiol 2022; 13:863873. [PMID: 35431991 PMCID: PMC9011003 DOI: 10.3389/fphys.2022.863873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 02/28/2022] [Indexed: 12/14/2022] Open
Abstract
Increases in beat-to-beat variability of electrocardiographic QT interval duration have repeatedly been associated with increased risk of cardiovascular events and complications. The measurements of QT variability are frequently normalized for the underlying RR interval variability. Such normalization supports the concept of the so-called immediate RR effect which relates each QT interval to the preceding RR interval. The validity of this concept was investigated in the present study together with the analysis of the influence of electrocardiographic morphological stability on QT variability measurements. The analyses involved QT and RR measurements in 6,114,562 individual beats of 642,708 separate 10-s ECG samples recorded in 523 healthy volunteers (259 females). Only beats with high morphology correlation (r > 0.99) with representative waveforms of the 10-s ECG samples were analyzed, assuring that only good quality recordings were included. In addition to these high correlations, SDs of the ECG signal difference between representative waveforms and individual beats expressed morphological instability and ECG noise. In the intra-subject analyses of both individual beats and of 10-s averages, QT interval variability was substantially more strongly related to the ECG noise than to the underlying RR variability. In approximately one-third of the analyzed ECG beats, the prolongation or shortening of the preceding RR interval was followed by the opposite change of the QT interval. In linear regression analyses, underlying RR variability within each 10-s ECG sample explained only 5.7 and 11.1% of QT interval variability in females and males, respectively. On the contrary, the underlying ECG noise contents of the 10-s samples explained 56.5 and 60.1% of the QT interval variability in females and males, respectively. The study concludes that the concept of stable and uniform immediate RR interval effect on the duration of subsequent QT interval duration is highly questionable. Even if only stable beat-to-beat measurements of QT interval are used, the QT interval variability is still substantially influenced by morphological variability and noise pollution of the source ECG recordings. Even when good quality recordings are used, noise contents of the electrocardiograms should be objectively examined in future studies of QT interval variability.
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Affiliation(s)
- Ondřej Toman
- Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czechia
- Department of Internal Medicine and Cardiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Katerina Hnatkova
- National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Martina Šišáková
- Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czechia
- Department of Internal Medicine and Cardiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | | | | | - Petra Barthel
- Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Tomáš Novotný
- Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czechia
- Department of Internal Medicine and Cardiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Irena Andršová
- Department of Internal Medicine and Cardiology, University Hospital Brno, Brno, Czechia
- Department of Internal Medicine and Cardiology, Faculty of Medicine, Masaryk University, Brno, Czechia
- *Correspondence: Irena Andršová
| | - Georg Schmidt
- Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Marek Malik
- Department of Internal Medicine and Cardiology, Faculty of Medicine, Masaryk University, Brno, Czechia
- National Heart and Lung Institute, Imperial College, London, United Kingdom
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Andršová I, Hnatkova K, Šišáková M, Toman O, Smetana P, Huster KM, Barthel P, Novotný T, Schmidt G, Malik M. Heart Rate Influence on the QT Variability Risk Factors. Diagnostics (Basel) 2020; 10:diagnostics10121096. [PMID: 33339231 PMCID: PMC7767205 DOI: 10.3390/diagnostics10121096] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/05/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022] Open
Abstract
QT interval variability, mostly expressed by QT variability index (QTVi), has repeatedly been used in risk diagnostics. Physiologic correlates of QT variability expressions have been little researched especially when measured in short 10-second electrocardiograms (ECGs). This study investigated different QT variability indices, including QTVi and the standard deviation of QT interval durations (SDQT) in 657,287 10-second ECGs recorded in 523 healthy subjects (259 females). The indices were related to the underlying heart rate and to the 10-second standard deviation of RR intervals (SDRR). The analyses showed that both QTVi and SDQT (as well as other QT variability indices) were highly statistically significantly (p < 0.00001) influenced by heart rate and that QTVi showed poor intra-subject reproducibility (coefficient of variance approaching 200%). Furthermore, sequential analysis of regression variance showed that SDQT was more strongly related to the underlying heart rate than to SDRR, and that QTVi was influenced by the underlying heart rate and SDRR more strongly than by SDQT (p < 0.00001 for these comparisons of regression dependency). The study concludes that instead of QTVi, simpler expressions of QT interval variability, such as SDQT, appear preferable for future applications especially if multivariable combination with the underlying heart rate is used.
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Affiliation(s)
- Irena Andršová
- Department of Internal Medicine and Cardiology, University Hospital Brno, Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00 Brno, Czech Republic; (I.A.); (M.Š.); (O.T.); (T.N.)
| | - Katerina Hnatkova
- National Heart and Lung Institute, Imperial College, 72 Du Cane Road, Shepherd’s Bush, London W12 0NN, UK;
| | - Martina Šišáková
- Department of Internal Medicine and Cardiology, University Hospital Brno, Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00 Brno, Czech Republic; (I.A.); (M.Š.); (O.T.); (T.N.)
| | - Ondřej Toman
- Department of Internal Medicine and Cardiology, University Hospital Brno, Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00 Brno, Czech Republic; (I.A.); (M.Š.); (O.T.); (T.N.)
| | - Peter Smetana
- Wilhelminenspital der Stadt Wien, Montleartstraße 37, 1160 Vienna, Austria;
| | - Katharina M. Huster
- Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, D-81675 Munich, Germany; (K.M.H.); (P.B.); (G.S.)
| | - Petra Barthel
- Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, D-81675 Munich, Germany; (K.M.H.); (P.B.); (G.S.)
| | - Tomáš Novotný
- Department of Internal Medicine and Cardiology, University Hospital Brno, Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00 Brno, Czech Republic; (I.A.); (M.Š.); (O.T.); (T.N.)
| | - Georg Schmidt
- Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, D-81675 Munich, Germany; (K.M.H.); (P.B.); (G.S.)
| | - Marek Malik
- National Heart and Lung Institute, Imperial College, 72 Du Cane Road, Shepherd’s Bush, London W12 0NN, UK;
- Department of Internal Medicine and Cardiology, Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00 Brno, Czech Republic
- Correspondence:
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