Solveig Magnusdottir ^1* Hilmisson Hugi ¹ Robert J. Thomas ^2*

• ¹ MyCardio LLC, Denver, United States
• ² Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States

High blood pressure (HBP) is an independent, modifiable driver of cardiovascular (CV) morbidity and mortality. Nocturnal hypertension and non-dipping of blood-pressure (NdBP) may be early markers of HBP. Similarly, to paUents with NdBP, individuals with non-dipping of heart rate (NdHR) during sleep have an increased risk of CV-disease, CV-events and CV-related mortality. The aim of this analysis was to evaluate if cardiopulmonary coupling (CPC)-analysis derived sleep states (stable/unstable non-rapid eye movement [NREM] sleep) and concomitant HR changes can provide informaUon about nocturnal BP.Plethysmogram (PLETH)-signals from the HeartBEAT-study (NCT01086800) were analyzed for CPC-sleep-states. Included in the analysis are sleep recordings from parUcipants (n=302) with acceptable PLETH-signal quality at baseline (n=302) and follow-up (n=267), all having confirmed CV-disease or CV-disease risk factors. The parUcipants had a high prevalence of obstrucUve sleep apnea (OSA), 98.4% with moderate-OSA (apnea hypopnea index, AHI ³15) and 29.6% severe-OSA (AH³30). IA "Heart-rate-module" was created to evaluate uUlity to idenUfy paUents more likely to have BP-dipping during sleep. PaUents who did not decrease ³10% in BP from wake to sleep were defined as NdBP and NdHR if HR during stable-NREM-sleep was higher than during unstable-NREM-sleep.The most significant difference in minimum HR (HRmin) was observed when comparing BP-dippers (56 ± 4 BPM) and non-BP-dippers (59 ± 4 BPM ) (p<0.0001) during diastolic bloodpressure in stable NREM-sleep. Higher HRmin were associated with an increased likelihood of being a non-dipper, with the strongest relaUonship with diastolic-BP and stable-NREM sleep.Every increase of 1-BPM during stable-NREM sleep was associated with ~4.4% increase in probability of being non-dipper (p=0.001). Non-dipping HR subjects have higher mean, sleep and wake-BP than HR-dippers. When CPAP-therapy is efficacious, and dipping-paXern is achieved -physical, and mental health is improved.HR-analyUcs in relaUon to the sleep period and CPC-spectrogram-esUmated sleep-states can provide novel and potenUally clinically useful informaUon on autonomic health. HR-dipping (or not) may be a useful screener of BP-dipping/non-dipping, to idenUfy individuals who may benefit from formal assessment of 24-hour-ambulatory BP. Such a stepped approach may enable a more pracUcal and applicable approach to diagnosing HBP.