1377 An Unexpected Signal: Autonomic Dysfunction Unmasked by Home Sleep Apnea Test

Abstract Introduction Clinically significant autonomic dysfunction can manifest in the context of sleep disordered breathing. We present a case where an abnormal pulse rate response to obstructive events was identified on Home Sleep Apnea Test (HSAT), leading to an additional autonomic diagnosis beyond obstructive sleep apnea (OSA). This case highlights how HSAT can identify rare comorbidities, such as cardiovascular dysautonomia, and how treatment of OSA can improve sleep disordered breathing and autonomic disease. Report of case(s) A 29-year-old female with BMI of 28, asthma, and migraines presented with persistent fatigue following COVID-19 and EBV infections two years prior. She endorsed snoring, witnessed apneas, excessive daytime sleepiness, morning headaches, and gasping in her sleep with associated palpitations. A WatchPAT HSAT revealed mild OSA (AHI 3% of 5.9/hr) with prominent non-sustained episodes of tachycardia related to obstructive events. On average, heart rate increased 40 bpm (maximum 56 bpm) after respiratory events, correlating with the clinical complaint. Given the exaggerated cardiac response noted on HSAT, concern for dysautonomia led to referral for cardiac evaluation of arrhythmias. She underwent a tilt table test that demonstrated a 46 bpm (>30) increase in heart rate, diagnostic of postural orthostatic tachycardia syndrome (POTS). After starting PAP therapy, she experienced significant improvement in her fatigue and migraines, along with resolution of nocturnal palpitations. Conclusion In OSA, oxygen desaturations, abnormal central nervous system arousals, and sympathetic activation can lead to autonomic dysregulation. Studies show that CPAP therapy can restore abnormal baroreceptor function and reduce sympathetic over reactivity. A typical pulse rate response to arousals or respiratory events may range from 6 to 15 bpm above baseline. This case highlights that an exaggerated heart rate variability detected on HSAT should prompt consideration of underlying dysautonomia. As HSATs become more widely used, recognition of atypical pulse rate response can allow for early diagnosis and management of cardiovascular autonomic dysfunction triggered by sleep disordered breathing. This case highlights unique takeaways: first, that OSA can worsen dysautonomia and its treatment can relieve symptoms of both OSA and autonomic dysfunction; and second, that HSAT features beyond standard OSA screening can help direct clinicians in working up comorbidities worsened by OSA. Support (if any)