Efficacy of melatonin with behavioural sleep-wake scheduling for delayed sleep-wake phase disorder: A double-blind, randomised clinical trial

BACKGROUND

Delayed Sleep-Wake Phase Disorder (DSWPD) is characterised by sleep initiation insomnia when attempting sleep at conventional times and difficulty waking at the required time for daytime commitments. Although there are published therapeutic guidelines for the administration of melatonin for DSWPD, to our knowledge, randomised controlled trials are lacking. This trial tested the efficacy of 0.5 mg melatonin, combined with behavioural sleep-wake scheduling, for improving sleep initiation in clinically diagnosed DSWPD patients with a delayed endogenous melatonin rhythm relative to patient-desired (or -required) bedtime (DBT).

METHODS

This randomised, placebo-controlled, double-blind clinical trial was conducted in an Australian outpatient DSWPD population. Following 1-wk baseline, clinically diagnosed DSWPD patients with delayed melatonin rhythm relative to DBT (salivary dim light melatonin onset [DLMO] after or within 30 min before DBT) were randomised to 4-wk treatment with 0.5 mg fast-release melatonin or placebo 1 h before DBT for at least 5 consecutive nights per week. All patients received behavioural sleep-wake scheduling, consisting of bedtime scheduled at DBT. The primary outcome was actigraphic sleep onset time. Secondary outcomes were sleep efficiency in the first third of time in bed (SE T1) on treatment nights, subjective sleep-related daytime impairment (Patient Reported Outcomes Measurement Information System [PROMIS]), PROMIS sleep disturbance, measures of daytime sleepiness, clinician-rated change in illness severity, and DLMO time.

FINDINGS

Between September 13, 2012 and September 1, 2014, 307 participants were registered; 116 were randomised to treatment (intention-to-treat n = 116; n = 62 males; mean age, 29.0 y). Relative to baseline and compared to placebo, sleep onset occurred 34 min earlier (95% confidence interval [CI] -60 to -8) in the melatonin group. SE T1 increased; PROMIS sleep-related impairment, PROMIS sleep disturbance, insomnia severity, and functional disability decreased; and a greater proportion of patients showed more than minimal clinician-rated improvement following melatonin treatment (52.8%) compared to placebo (24.0%) (P < 0.05). The groups did not differ in the number of nights treatment was taken per protocol. Post-treatment DLMO assessed in a subset of patients (n = 43) was not significantly different between groups. Adverse events included light-headedness, daytime sleepiness, and decreased libido, although rates were similar between treatment groups. The clinical benefits or safety of melatonin with long-term treatment were not assessed, and it remains unknown whether the same treatment regime would benefit patients experiencing DSWPD sleep symptomology without a delay in the endogenous melatonin rhythm.

CONCLUSIONS

In this study, melatonin treatment 1 h prior to DBT combined with behavioural sleep-wake scheduling was efficacious for improving objective and subjective measures of sleep disturbances and sleep-related impairments in DSWPD patients with delayed circadian phase relative to DBT. Improvements were achieved largely through the sleep-promoting effects of melatonin, combined with behavioural sleep-wake scheduling.

TRIAL REGISTRATION

This trial was registered with the Australian New Zealand Clinical Trials Registry, ACTRN12612000425897.

Morning and Evening Blue-Enriched Light Exposure Alters Metabolic Function in Normal Weight Adults

Increasing evidence points to associations between light-dark exposure patterns, feeding behavior, and metabolism. This study aimed to determine the acute effects of 3 hours of morning versus evening blue-enriched light exposure compared to dim light on hunger, metabolic function, and physiological arousal. Nineteen healthy adults completed this 4-day inpatient protocol under dim light conditions (<20lux). Participants were randomized to 3 hours of blue-enriched light exposure on Day 3 starting either 0.5 hours after wake (n = 9; morning group) or 10.5 hours after wake (n = 10; evening group). All participants remained in dim light on Day 2 to serve as their baseline. Subjective hunger and sleepiness scales were collected hourly. Blood was sampled at 30-minute intervals for 4 hours in association with the light exposure period for glucose, insulin, cortisol, leptin, and ghrelin. Homeostatic model assessment of insulin resistance (HOMA-IR) and area under the curve (AUC) for insulin, glucose, HOMA-IR and cortisol were calculated. Comparisons relative to baseline were done using t-tests and repeated measures ANOVAs. In both the morning and evening groups, insulin total area, HOMA-IR, and HOMA-IR AUC were increased and subjective sleepiness was reduced with blue-enriched light compared to dim light. The evening group, but not the morning group, had significantly higher glucose peak value during blue-enriched light exposure compared to dim light. There were no other significant differences between the morning or the evening groups in response to blue-enriched light exposure. Blue-enriched light exposure acutely alters glucose metabolism and sleepiness, however the mechanisms behind this relationship and its impacts on hunger and appetite regulation remain unclear. These results provide further support for a role of environmental light exposure in the regulation of metabolism.

Using domiciliary non-invasive ventilator data downloads to inform clinical decision-making to optimise ventilation delivery and patient compliance

Introduction

Ventilation parameter data from patients receiving home mechanical ventilation can be collected via secure data cards and modem technology. This can then be reviewed by clinicians and ventilator prescriptions adjusted. Typically available measures include tidal volume (V_T), leak, respiratory rate, minute ventilation, patient triggered breaths, achieved pressures and patient compliance. This study aimed to assess the potential impact of ventilator data downloads on management of patients requiring home non-invasive ventilation (NIV).

Methods

A longitudinal within-group design with repeated measurements was used. Baseline ventilator data were downloaded, reviewed and adjustments made to optimise ventilation. Leak, V_T and compliance data were collected for comparison at the first review and 3-7 weeks later. Ventilator data were monitored and amended remotely via a modem by a consultant physiotherapist between the first review and second appointment.

Results

Analysis of data from 52 patients showed increased patient compliance (% days used >4 hours) from 90% to 96% (p=0.007), increased usage from 6.53 to 6.94 hours (p=0.211) and a change in V_T(9.4 vs 8.7 mL/kg/ideal body weight, p=0.022). There was no change in leak following review of NIV prescriptions (mean (SD): 43 (23.4) L/min vs 45 (19.9)L/min, p=0.272).

Conclusion

Ventilator data downloads, via early remote assessment, can help optimise patient ventilation through identification of modifiable factors, in particular interface leak and ventilator prescriptions. However, a prospective study is required to assess whether using ventilator data downloads provides value in terms of patient outcomes and cost-effectiveness. The presented data will help to inform the design of such a study.

Whole-genome association analyses of sleep-disordered breathing phenotypes in the NHLBI TOPMed program

BACKGROUND

Sleep-disordered breathing is a common disorder associated with significant morbidity. The genetic architecture of sleep-disordered breathing remains poorly understood. Through the NHLBI Trans-Omics for Precision Medicine (TOPMed) program, we performed the first whole-genome sequence analysis of sleep-disordered breathing.

METHODS

The study sample was comprised of 7988 individuals of diverse ancestry. Common-variant and pathway analyses included an additional 13,257 individuals. We examined five complementary traits describing different aspects of sleep-disordered breathing: the apnea-hypopnea index, average oxyhemoglobin desaturation per event, average and minimum oxyhemoglobin saturation across the sleep episode, and the percentage of sleep with oxyhemoglobin saturation < 90%. We adjusted for age, sex, BMI, study, and family structure using MMSKAT and EMMAX mixed linear model approaches. Additional bioinformatics analyses were performed with MetaXcan, GIGSEA, and ReMap.

RESULTS

We identified a multi-ethnic set-based rare-variant association (p = 3.48 × 10-8) on chromosome X with ARMCX3. Additional rare-variant associations include ARMCX3-AS1, MRPS33, and C16orf90. Novel common-variant loci were identified in the NRG1 and SLC45A2 regions, and previously associated loci in the IL18RAP and ATP2B4 regions were associated with novel phenotypes. Transcription factor binding site enrichment identified associations with genes implicated with respiratory and craniofacial traits. Additional analyses identified significantly associated pathways.

CONCLUSIONS

We have identified the first gene-based rare-variant associations with objectively measured sleep-disordered breathing traits. Our results increase the understanding of the genetic architecture of sleep-disordered breathing and highlight associations in genes that modulate lung development, inflammation, respiratory rhythmogenesis, and HIF1A-mediated hypoxic response.

Obstructive sleep apnoea but not central sleep apnoea is associated with left ventricular remodelling after acute myocardial infarction

Obejctive

Obstructive sleep apnoea (OSA) increases left ventricular transmural pressure more than central sleep apnoea (CSA) owing to negative intrathoracic pressure swings. We tested the hypothesis that the severity of OSA, and not CSA, is therefore associated with spheric cardiac remodelling after acute myocardial infarction.

Methods

This sub-analysis of a prospective observational study included 24 patients with acute myocardial infarction who underwent primary percutaneous coronary intervention. Spheric remodelling, calculated according to the sphericity index, was assessed by cardiac magnetic resonance imaging at baseline and 12 weeks after acute myocardial infarction. OSA and CSA [apnoea-hypopnoea index (AHI) ≥ 5/hour] were diagnosed by polysomnography.

Results

Within 12 weeks after acute myocardial infarction, patients with OSA exhibited a significant increase in systolic sphericity index compared to patients without sleep-disordered breathing (no SDB) and patients with CSA (OSA vs. CSA vs. no SDB: 0.05 ± 0.04 vs. 0.01 ± 0.04 vs. − 0.03 ± 0.03, p = 0.002). In contrast to CSA, the severity of OSA was associated with an increase in systolic sphericity index after accounting for TIMI-flow before percutaneous coronary intervention, infarct size, pain-to-balloon-time and systolic blood pressure [OSA: B (95% CI) 0.443 (0.021; 0.816), p = 0.040; CSA: 0.193 (− 0.134; 0.300), p = 0.385].

Conclusion

In contrast to CSA and no SDB, OSA is associated with spheric cardiac remodelling within the first 12 weeks after acute myocardial infarction. Data suggest that OSA-related negative intrathoracic pressure swings may contribute to this remodelling after acute myocardial infaction.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01684-z) contains supplementary material, which is available to authorized users.

Distinct impacts of sleep-disordered breathing on glycemic variability in patients with and without diabetes mellitus

BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent in patients with diabetes mellitus (DM) and heart failure (HF) and contributes to poor cardiovascular outcomes. Enlarged glycemic variability (GV) is a risk factor of cardiac events independently of average blood glucose level, but the influence of SDB on GV is uncertain. In this study, we examined whether the impact of SDB on GV is modified by the presence of DM with or without HF.

METHODS AND RESULTS

Two hundred three patients (67.5±14.1 [SD] years old, 132 males) who were admitted to our institute for examination or treatment of DM and/or HF underwent continuous glucose monitoring and polysomnography. Both HbA1c (8.0±2.0 vs. 5.7±0.4%) and mean amplitude of glycemic excursion (MAGE, median: 95.5 vs. 63.5 mg/dl) were significantly higher in a DM group (n = 100) than in a non-DM group (n = 103), but apnea-hypopnea index (AHI: 29.0±22.7 vs. 29.3±21.5) was similar in the two groups. AHI was correlated with log MAGE in the non-DM group but not in the DM group, and multivariate regression analysis revealed that AHI was an independent variable for log MAGE in the non-DM group but not in the DM group. We then divided the non-DM patients into two subgroups according to BNP level (100 pg/ml). AHI was positively correlated with log MAGE (r = 0.74, p<0.001) in the non-DM low-BNP subgroup, but such a correlation was not found in the non-DM high-BNP subgroup. Continuous positive airway pressure (CPAP) reduced MAGE from 75.3 to 53.0 mg/dl in the non-DM group but did not reduce MAGE in the DM group.

CONCLUSION

Severity of SDB was associated with higher GV, but DM as well as HF diminished the contribution of SDB to GV. Treatment with CPAP was effective for reduction of GV only in patients without DM.

Proteomic Biomarkers of the Apnea Hypopnea Index and Obstructive Sleep Apnea: Insights into the Pathophysiology of Presence, Severity, and Treatment Response

Obstructive sleep apnea (OSA), a disease associated with excessive sleepiness and increased cardiovascular risk, affects an estimated 1 billion people worldwide. The present study examined proteomic biomarkers indicative of presence, severity, and treatment response in OSA. Participants (n = 1391) of the Stanford Technology Analytics and Genomics in Sleep study had blood collected and completed an overnight polysomnography for scoring the apnea−hypopnea index (AHI). A highly multiplexed aptamer-based array (SomaScan) was used to quantify 5000 proteins in all plasma samples. Two separate intervention-based cohorts with sleep apnea (n = 41) provided samples pre- and post-continuous/positive airway pressure (CPAP/PAP). Multivariate analyses identified 84 proteins (47 positively, 37 negatively) associated with AHI after correction for multiple testing. Of the top 15 features from a machine learning classifier for AHI ≥ 15 vs. AHI < 15 (Area Under the Curve (AUC) = 0.74), 8 were significant markers of both AHI and OSA from multivariate analyses. Exploration of pre- and post-intervention analysis identified 5 of the 84 proteins to be significantly decreased following CPAP/PAP treatment, with pathways involving endothelial function, blood coagulation, and inflammatory response. The present study identified PAI-1, tPA, and sE-Selectin as key biomarkers and suggests that endothelial dysfunction and increased coagulopathy are important consequences of OSA, which may explain the association with cardiovascular disease and stroke.

The impact of epicardial adipose tissue in patients with acute myocardial infarction

AIMS

Epicardial adipose tissue (EAT) has been linked to impaired reperfusion success after percutaneous coronary intervention (PCI). Whether EAT predicts myocardial damage in the early phase after acute myocardial infarction (MI) is unclear. Therefore, we investigated whether EAT in patients with acute MI is associated with more microvascular obstruction (MVO), greater ST-deviation, larger infarct size and reduced myocardial salvage index (MSI).

METHODS AND RESULTS

This retrospective analysis of a prospective observational study including patients with acute MI (n = 54) undergoing PCI and 12 healthy matched controls. EAT, infarct size and MSI were analyzed with cardiac magnetic resonance imaging, conducted 3-5 days and 12 weeks after MI. Patients with acute MI showed higher EAT volume than healthy controls (46 [25.;75. percentile: 37;59] vs. 24 [15;29] ml, p < 0.001). The high EAT group (above median) showed significantly more MVO (2.22 [0.00;5.38] vs. 0.0 [0.00;2.18] %, p = 0.004), greater ST-deviation (0.38 [0.22;0.55] vs. 0.15 [0.03;0.20] mV×10-1, p = 0.008), larger infarct size at 12 weeks (23 [17;29] vs. 10 [4;16] %, p < 0.001) and lower MSI (40 [37;54] vs. 66 [49;88] %, p < 0.001) after PCI than the low EAT group. After accounting for demographic characteristics, body-mass index, heart volume, infarct location, TIMI-flow grade as well as apnea-hypopnea index, EAT was associated with infarct size at 12 weeks (B = 0.38 [0.11;0.64], p = 0.006), but not with MSI.

CONCLUSIONS

Patients with acute MI showed higher volume of EAT than healthy individuals. High EAT was linked to more MVO and greater ST-deviation. EAT was associated with infarct size, but not with MSI.

Effect of CPAP therapy on kidney function in patients with obstructive sleep apnoea and chronic kidney disease: a protocol for a randomised controlled clinical trial

INTRODUCTION

Obstructive sleep apnoea (OSA) is common in patients with chronic kidney disease (CKD) and may contribute to the progression of kidney disease either through direct effects of hypoxia on the kidney or indirectly through hypoxaemia-induced oxidative stress, endothelial dysfunction, inflammation, activation of the renin-angiotensin and sympathetic nervous systems, and hypertension. Treatment of OSA with continuous positive airway pressure (CPAP) improves many of these physiological abnormalities in patients with normal renal function, though to date there are no trials evaluating the effect of OSA treatment on kidney function in patients with CKD. The purpose of this study is to test the feasibility and efficacy of CPAP therapy in CKD patients with OSA.

METHODS AND ANALYSIS

The study is a randomised, controlled, non-blinded, parallel clinical trial in which patients with established CKD are screened for OSA. Patients with OSA are randomised to either conventional medical therapy (control group) or medical therapy and CPAP (CPAP group) and followed for 1 year. The primary outcome is the change in estimated glomerular filtration rate. Secondary outcomes are the change in the urinary albumin/creatinine ratio, the Epworth Sleepiness Scale , Pittsburgh Sleep Quality Index and Kidney Disease Quality of Life questionnaire.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Conjoint Health Research Ethics Board (ID: REB15-0055). Results from this study will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02420184; Pre-results.

Empagliflozin inhibits increased Na influx in atrial cardiomyocytes of patients with HFpEF

AIMS

Heart failure with preserved ejection fraction (HFpEF) causes substantial morbidity and mortality. Importantly, atrial remodelling and atrial fibrillation are frequently observed in HFpEF. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have recently been shown to improve clinical outcomes in HFpEF, and post-hoc analyses suggest atrial anti-arrhythmic effects. We tested if isolated human atrial cardiomyocytes from patients with HFpEF exhibit an increased Na influx, which is known to cause atrial arrhythmias, and if that is responsive to treatment with the SGTL2i empagliflozin.

METHODS AND RESULTS

Cardiomyocytes were isolated from atrial biopsies of 124 patients (82 with HFpEF) undergoing elective cardiac surgery. Na influx was measured with the Na-dye Asante Natrium Green-2 AM (ANG-2). Compared to patients without heart failure (NF), Na influx was doubled in HFpEF patients (NF vs. HFpEF: 0.21 ± 0.02 vs. 0.38 ± 0.04 mmol/L/min (N = 7 vs. 18); P = 0.0078). Moreover, late INa (measured via whole-cell patch clamp) was significantly increased in HFpEF compared to NF. Western blot and HDAC4 pulldown assay indicated a significant increase in CaMKII expression, CaMKII autophosphorylation, CaMKII activity, and CaMKII-dependent NaV1.5 phosphorylation in HFpEF compared to NF, whereas NaV1.5 protein and mRNA abundance remained unchanged. Consistently, increased Na influx was significantly reduced by treatment not only with the CaMKII inhibitor autocamtide-2-related inhibitory peptide (AIP), late INa inhibitor tetrodotoxin (TTX) but also with sodium/hydrogen exchanger 1 (NHE1) inhibitor cariporide. Importantly, empagliflozin abolished both increased Na influx and late INa in HFpEF. Multivariate linear regression analysis, adjusting for important clinical confounders, revealed HFpEF to be an independent predictor for changes in Na handling in atrial cardiomyocytes.

CONCLUSION

We show for the first time increased Na influx in human atrial cardiomyocytes from HFpEF patients, partly due to increased late INa and enhanced NHE1-mediated Na influx. Empagliflozin inhibits Na influx and late INa, which could contribute to anti-arrhythmic effects in patients with HFpEF.

Promoting sustained access to cognitive behavioral therapy for insomnia in Australia: a system-level implementation program

STUDY OBJECTIVES

Insomnia is a highly prevalent and debilitating disorder. Cognitive behavioral therapy for insomnia (CBTi) is the recommended "first line" treatment, but is accessed by a minority of people with insomnia. This paper describes a system-level implementation program to improve access to CBTi in Australia to inform CBTi implementation in other locations.

METHODS

From 2019-2023, we conducted a program of work to promote sustained change in access to CBTi in Australia. Three distinct phases included (1) scoping and mapping barriers to CBTi access, (2) analysis and synthesis of barriers and facilitators to devise change goals, and (3) structured promotion and coordination of change. We used a system-level approach, knowledge brokerage, and codesign, and drew on qualitative, quantitative, and implementation science methods.

RESULTS

We identified barriers to CBTi access from the perspectives of people with insomnia, primary care clinicians, and the health system. A stakeholder advisory committee was convened to codesign change goals, identify modifiable barriers, devise program logic, and drive change strategies. We commenced a program to promote system-level change in CBTi access via: improved awareness and education of insomnia among primary care clinicians, self-guided interventions, and advocating to Government for additional CBTi funding mechanisms.

CONCLUSIONS

This implementation program made significant progress toward improving access to CBTi in Australia. Ongoing work is required to continue this program, as long-term system-level change requires significant and sustained time, effort, and resources from multiple stakeholders. This program may be used to inform CBTi implementation activities in other locations.

CITATION

Sweetman A, McEvoy RD, Frommer MS, et al. Promoting sustained access to cognitive behavioral therapy for insomnia in Australia: a system-level implementation program. J Clin Sleep Med. 2025;21(2):325-335.

Predictors of Nocturnal Hypoxemic Burden in Patients Undergoing Elective Coronary Artery Bypass Grafting Surgery

Background: Nocturnal hypoxemia has been linked to increased cardiovascular morbidity and mortality. Several common diseases, such as sleep-disordered breathing (SDB), heart failure (HF), obesity, and pulmonary disease, coincide with an elevated nocturnal hypoxemic burden with and without repetitive desaturations. Research question: This study aimed to evaluate the association of relevant common diseases with distinctive metrics of nocturnal hypoxemic burden with and without repetitive desaturations in patients undergoing coronary artery bypass grafting surgery. Study design and methods: In this subanalysis of the prospective observational study, CONSIDER-AF (NCT02877745) portable SDB monitoring was performed on 429 patients with severe coronary artery disease the night before cardiac surgery. Pulse oximetry was used to determine nocturnal hypoxemic burden, as defined by total recording time spent with oxygen saturation levels < 90% (T90). T90 was further characterized as T90 due to intermittent hypoxemia (T90desaturation) and T90 due to nonspecific and noncyclic SpO2-drifts (T90non-specific). Results: Multivariable linear regression analysis identified SDB (apnea-hypopnea-index ≥ 15/h; B [95% CI]: 6.5 [0.4; 12.5], p = 0.036), obesity (8.2 [2.5; 13.9], p = 0.005), and mild-to-moderate chronic obstructive pulmonary disease (COPD, 16.7 [8.5; 25.0], p < 0.001) as significant predictors of an increased nocturnal hypoxemic burden. Diseases such as SDB, obesity and HF were significantly associated with elevated T90desaturation. In contrast, obesity and mild-to-moderate COPD were significant modulators of T90non-specific. Interpretation: SDB and leading causes for SDB, such as obesity and HF, are associated with an increased nocturnal hypoxemic burden with repetitive desaturations. Potential causes for hypoventilation syndromes, such as obesity and mild-to-moderate COPD, are linked to an increased hypoxemic burden without repetitive desaturations. Clinical Trial Registration: ClinicalTrials.gov identifier: NCT02877745.

The noninvasive ventilation outcomes score in patients requiring NIV for COPD exacerbation without prior evidence of airflow obstruction

Introduction

Exacerbation of COPD complicated by respiratory acidaemia is the commonest indication for noninvasive ventilation (NIV). The NIV outcomes (NIVO) score offers the best estimate of survival for those ventilated. Unfortunately, two-thirds of cases of COPD are unrecognised, and patients may present without COPD having been confirmed by spirometry.

Methods

In the 10-centre NIVO validation study there was no pre-admission spirometry in 111 of 844 consecutive patients (termed "clinical diagnosis" patients). We compared the performance of the NIVO, DECAF and CURB-65 scores for in-hospital mortality in the clinical diagnosis cohort. Usual clinical practice was not influenced, but confirmation of COPD in the year following discharge was captured.

Results

In the clinical diagnosis cohort, in-hospital mortality was 19.8% and rose incrementally across the NIVO risk categories, consistent with the NIVO validation cohort. NIVO showed good discrimination in the clinical diagnosis cohort: area under the receiver operating curve 0.724, versus 0.79 in the NIVO validation cohort. At 1 year after discharge, 41 of 89 clinical diagnosis patients had undertaken diagnostic spirometry; 33 of 41 had confirmation of airflow obstruction (forced expiratory volume in 1 s/(forced) vital capacity <0.7), meaning the diagnosis of COPD was incorrect in 19.5% of cases.

Discussion

These data support the use of the NIVO score in patients with a "clinical diagnosis" of COPD. NIVO can help guide shared decision-making, assess risk-adjusted outcomes by centre and challenge prognostic pessimism. Accurate diagnosis is critical to ensure that acute and long-term treatment is optimised; this study highlights failings in the follow-up of such patients.

Sleep-Disordered Breathing, Advanced Age, and Diabetes Mellitus Are Associated with De Novo Atrial Fibrillation after Cardiac Surgery

Background: Postoperative de novo atrial fibrillation (POAF) is one of the most frequently encountered complications following cardiac surgery. Despite the identification of several risk factors, the link between sleep-disordered breathing (SDB) and POAF has barely been examined. The objective of this prospective observational study was to determine whether severe SDB is associated with POAF in patients after elective coronary artery bypass grafting (CABG) surgery. Study design and methods: The incidence and preoperative predictors of in-hospital POAF were assessed in 272 patients undergoing CABG surgery at the University Medical Center Regensburg (Germany). In-hospital POAF was detected by continuous telemetry-ECG monitoring and 12-lead resting ECGs within the first seven postoperative days. POAF that occurred after hospital discharge within 60 days post CABG surgery was classified as post-hospital POAF and was ascertained by standardized phone interviews together with the patients' medical files, including routinely performed Holter-ECG monitoring at 60 days post CABG surgery. The night before surgery, portable SDB monitoring was used to assess the presence and type of severe SDB, defined by an apnea-hypopnea index ≥ 30/h. Results: The incidence of in-hospital POAF was significantly higher in patients with severe SDB compared to those without severe SDB (30% vs. 15%, p = 0.009). Patients with severe SDB suffered significantly more often from POAF at 60 days post CABG surgery compared to patients without severe SDB (14% vs. 5%, p = 0.042). Multivariable logistic regression analysis showed that severe SDB (odds ratio, OR [95% confidence interval, CI]: 2.23 [1.08; 4.61], p = 0.030), age ≥ 65 years (2.17 [1.04; 4.53], p = 0.038), and diabetes mellitus (2.27 [1.15; 4.48], p = 0.018) were significantly associated with in-hospital POAF. After additional adjustment for heart failure, the association between sleep apnea and postoperative atrial fibrillation was attenuated (1.99 [0.92; 4.31], p = 0.081). Conclusions: Amongst established risk factors, severe SDB was significantly associated with in-hospital POAF in patients undergoing CABG surgery. Whether SDB contributes to POAF independently of heart failure and whether risk for POAF may be alleviated by proper treatment of SDB merits further investigation.

Hypoxaemic burden in heart failure patients receiving adaptive servo-ventilation

AIMS

This study aimed to assess the effectiveness of adaptive servo-ventilation (ASV) for lowering hypoxaemic burden components in heart failure with reduced ejection fraction (HFrEF) patients.

METHODS AND RESULTS

Fifty-six stable HFrEF patients with left ventricular ejection fraction ≤ 40 were randomized to receive either ASV (n = 27; 25 males) or optimal medical management or optimal medical management alone (n = 29; 26 males). Patients underwent overnight polysomnography at baseline and a 12 week follow-up visit. We quantified hypoxaemic as time spent at <90% oxygen saturation (T90) decomposed into desaturation-related components (T90desaturation ) and non-specific drifts (T90non-specific ). In the ASV arm, T90 significantly shortened by nearly 60% from 50.1 ± 95.8 min at baseline to 20.5 ± 33.0 min at follow-up compared with 59.6 ± 88 and 65.4 ± 89.6 min in the control arm (P = 0.009). ASV reduced the apnoea-related component (T90desaturation ) from 37.7 ± 54.5 to 2.1 ± 7.3 min vs. 37.7 ± 54.5 and 40.4 ± 66.4 min in the control arm (P = 0.008). A significant non-specific T90 component of 19.6 ± 31.8 min persisted during ASV. In adjusted multivariable regression, T90desaturation was significantly associated with the ratio of the forced expiratory volume in the first second to the forced vital capacity of the lungs (β = 0.336, 95% confidence interval 0.080 to 0.593; P = 0.011) and T90non-specific with left ventricular ejection fraction (β = -0.345, 95% confidence interval -0.616 to -0.073; P = 0.014).

CONCLUSIONS

ASV effectively suppresses the sleep apnoea-related component of hypoxaemic burden in HFrEF patients. A significant hypoxaemic burden not directly attributable to sleep apnoea but related to the severity of heart failure remains and may adversely affect cardiovascular long-term outcomes.

Systemic inflammation predicts diastolic dysfunction in patients with sleep disordered breathing

Heart failure with preserved ejection fraction (HFpEF) constitutes approximately half of all patients with heart failure and causes mortality similar to heart failure with reduced ejection fraction [1]. HFpEF is highly relevant as novel evidence-based therapies emerge but treatment options remain limited [1]. Diastolic dysfunction is a hallmark of HFpEF and is also very common in up to 80% of high-risk cardiovascular patients undergoing cardiac surgery [2]. Even without overt HFpEF, echocardiographic diastolic dysfunction is independently associated with increased mortality [3]. Another important characteristic of HFpEF is the frequent presence of comorbidities, with one of the most important being sleep disordered breathing (SDB). SDB affects over one billion patients in the general population and is highly prevalent in cardiovascular high-risk patients, which underscores its high socioeconomic relevance [4]. Interestingly, SDB patients frequently exhibit diastolic dysfunction [5]; however, the underlying mechanisms remain elusive thus far [6]. In this cross-sectional experimental study, we analysed the role of inflammation and fibrosis for diastolic dysfunction in cardiovascular high-risk patients stratified by the prevalence of SDB, which may provide a groundwork for future therapeutic strategies.

Systemic and myocardial inflammation are associated with diastolic cardiac dysfunction in patients with sleep disordered breathing, which may have therapeutic implications https://bit.ly/3vxAECC