Hypothetical Mechanisms for Increased Risk of Sudden Cardiac Death During Sleep in URM Populations




Rai, Shefali
Smith, Michael


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Purpose: Sudden cardiac death (SCD) is one of the leading causes of death. It is an unanticipated natural death from a cardiac pathology that occurs within an hour of onset of symptoms and no prior fatal condition. The majority of SCD are due to fatal arrhythmias. Prolongation of ventricular depolarization and repolarization, represented by the QT interval, affects impulse conduction and therefore increases the risk of these fatal arrhythmias. Additionally, SCD is presumed to be the primary cause of death during sleep including in underrepresented minority (URM) populations. Factors such as BMI and home environment can negatively impact sleep quality and potentially lead to increased susceptibility to sleep apnea and SCD within URM populations. Preliminary findings from our lab using a simulated obstructive sleep apnea (OSA) model demonstrates increased QT interval duration during sleep apnea and a follow-up study in patients with OSA as summarized below. This poster summarizes these prior findings and describes proposed studies to test the hypothesis that QT interval prolongation during sleep apneic events will be more pronounced in URM populations. Methods: We reviewed lab studies demonstrating the mean change in QT intervals throughout the night in individuals with sleep apnea. Preliminary Results: Individuals with OSA demonstrate prolonged mean QT intervals (> 400 ms). The mean QT interval duration during sleep apnea measured late in the night (433 ms) was longer than the interval measured early in the night (423 ms). The QT interval duration was longer in African American individuals (450 ms) when compared to Caucasian individuals (432 ms). Conclusion: Sleep apnea is associated with cardiovascular disease and can therefore potentially lead to increased risk of SCD in sleep. The OSA model lab studies show that sleep apnea can lead to prolonged QT intervals and a potential for URM to be at a greater risk of arrhythmia and SCD during sleep apneic events. This poster will focus on developing a new study for a series of physiologic studies to address the hypothesis that URM subjects with OSA are at increased risk of SCD during sleep. Student doctor Rai was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Number (R25HL125447). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.