Andrea Segreti (1)(2)(3), Simone Pasquale Crispino (1)(2), Daniele Valente (1)(2), Emiliano Guerra (4), Martina Ciancio (1)(2), Luca Carnuccio (4)(5), Antonio Moffa (4)(5), Manuele Casale (4)(5), Francesco Grigioni (1)(2).

(1) Cardiology Unit, Fondazione Policlinico Universitario Campus Bio-Medico, Rome.
(2)Research Unit of Cardiovascular Science, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma.
(3) Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome.
(4) Cardiology Division, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Policlinico di Modena.
(5) School of Medicine, Campus Bio-Medico University Rome.
(6) Integrated Therapies in Otolaryngology, Fondazione Policlinico Universitario Campus Bio-Medico, Rome.

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Introduction: Obstructive Sleep Apnea Syndrome (OSAS) is a prevalent disorder characterized by repetitive episodes of upper airway obstruction during sleep, leading to significant cardiovascular risks. Despite its high prevalence and health burden, OSAS remains underdiagnosed. Cardiovascular alterations are common in OSAS patients, making the electrocardiogram (ECG) a potential non-invasive tool to identify individuals at increased cardiovascular risk due to OSAS.

Methods: This retrospective investigated the association between OSAS severity and ECG metrics in patients scheduled for OSAS surgical treatment. Data were collected from patient records at a single university hospital. The study enrolled 152 patients, aged 18 years and older, all diagnosed with OSAS and awaiting surgical correction. The ECG characteristics analyzed included heart rate, PR segment, QRS morphology and intraventricular conduction defects, QT interval, and axis measurements. Polysomnographic evaluations provided data on sleep apnea severity, including the Apnea-Hypopnea Index (AHI) and the Oxygen Desaturation Index (ODI). The primary objective was to correlate OSAS severity (AHI and ODI) with ECG alterations.

Results: The study identified significant correlations between OSAS severity and various ECG metrics. The PR interval showed a modest yet significant positive correlation with AHI (r=0.228, p=0.036), indicating that increased sleep apnea severity may be associated with prolonged atrioventricular conduction time. Additionally, the P wave axis demonstrated a significant negative correlation with AHI in the supine position (r=-0.670, p=0.024), suggesting an impact of sleep position on atrial electrical orientation. The Respiratory Disturbance Index (RDI) also showed a significant negative correlation with the P wave axis (r=-0.578, p=0.024). A notable inverse correlation was found between oxygen saturation (SpO2) and the PR interval (r=-0.306, p=0.011), indicating that as oxygen saturation decreases, the PR interval lengthens.
No significant correlations were observed between AHI and the QRS duration (r=0.179, p=0.114), QT interval (r=0.140, p=0.202), or QTc interval (r=0.068, p=0.536), suggesting that sleep apnea severity does not significantly affect ventricular depolarization and repolarization in this study population. Moreover, the QRS and T wave axes did not show significant correlations with AHI, indicating no direct influence of sleep apnea severity on ventricular depolarization or repolarization orientation.

Conclusions: This study confirms the significant association between OSAS and various electrocardiographic alterations. These ECG changes suggest that OSAS severity is likely linked to atrial electrical remodeling and prolonged atrioventricular conduction, emphasizing the importance of cardiovascular clinical and electrocardiographic monitoring in OSAS patients. Early detection and management of OSAS could potentially reduce its cardiovascular impacts. Further prospective studies are needed to explore the underlying mechanisms and therapeutic strategies.