AUTHOR=Hilmisson Hugi , Thomas Robert Joseph , Magnusdottir Solveig 

TITLE=Cardiopulmonary coupling-calculated sleep stability and nocturnal heart rate kinetics as a potential indicator for cardiovascular health: a relationship with blood pressure dipping

JOURNAL=Frontiers in Sleep

VOLUME=3

YEAR=2024

URL=https://www.frontiersin.org/journals/sleep/articles/10.3389/frsle.2024.1230958

DOI=10.3389/frsle.2024.1230958

ISSN=2813-2890

ABSTRACT=<sec><title>Introduction</title><p>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. Similar to patients 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 heart rate (HR) changes can provide information about nocturnal blood pressure (BP).</p></sec><sec><title>Method</title><p>Plethysmogram (pleth) signals from the HeartBEAT study (NCT01086800) were analyzed for CPC sleep states. Included in the analysis are sleep recordings from participants with acceptable pleth-signal quality at baseline (<italic>n</italic> = 302) and follow-up (<italic>n</italic> = 267), all having confirmed CV disease or CV-disease risk factors. The participants had a high prevalence of obstructive sleep apnea (OSA), 98.4% with moderate-OSA [apnea–hypopnea index (AHI) ≥ 15) and 29.6% severe OSA (AHI ≥ 30). A “heart-rate module” was created to evaluate the utility of identifying patients more likely to have BP dipping during sleep. Patients who did not have a decrease of ≥10% in their BP from wake to sleep were defined as NdBP and NdHR if their heart rate during stable-NREM sleep was higher than during unstable-NREM sleep.</p></sec><sec><title>Results</title><p>The most significant difference in minimum HR (HR<sub>min</sub>) was observed when comparing BP dippers [56 ± 4 beats per minute (BPM)] and non-BP dippers (59 ± 4 BPM; <italic>p</italic> &lt; 0.0001) during diastolic blood pressure in stable-NREM sleep. Higher HR<sub>min</sub> were associated with an increased likelihood of being a non-dipper, with the strongest relationship with diastolic BP and stable-NREM sleep. Every increase of 1 BPM during stable-NREM sleep was associated with an ~4.4% increase in the probability of NdBP (<italic>p</italic> = 0.001). Subjects with NdHR have higher mean BP during sleep and wake periods than HR dippers. When continuous positive airway pressure therapy is efficacious, and a dipping pattern is achieved—physical and mental health is improved.</p></sec><sec><title>Conclusion</title><p>HR analytics in relation to the sleep period and the CPC spectrogram-estimated sleep states can provide novel and potentially clinically useful information on autonomic health. HR dipping (or not) may be a useful screener of BP dipping or non-dipping to identify individuals who may benefit from a formal assessment of 24-h ambulatory BP. Such a stepped approach may enable a more practical and applicable approach to diagnosing HBP.</p></sec><sec><title>Clinical Trial Registration</title><p>The Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study is registered at <ext-link ext-link-type="uri" xlink:href="https://clinicaltrials.gov/ct2/show/NCT01086800" xmlns:xlink="http://www.w3.org/1999/xlink">clinicaltrials.gov/ct2/show/NCT01086800</ext-link>.</p></sec>