Lifestyle management of hypertension: International Society of Hypertension position paper endorsed by the World Hypertension League and European Society of Hypertension

Hypertension, defined as persistently elevated systolic blood pressure (SBP) >140 mmHg and/or diastolic blood pressure (DBP) at least 90 mmHg (International Society of Hypertension guidelines), affects over 1.5 billion people worldwide. Hypertension is associated with increased risk of cardiovascular disease (CVD) events (e.g. coronary heart disease, heart failure and stroke) and death. An international panel of experts convened by the International Society of Hypertension College of Experts compiled lifestyle management recommendations as first-line strategy to prevent and control hypertension in adulthood. We also recommend that lifestyle changes be continued even when blood pressure-lowering medications are prescribed. Specific recommendations based on literature evidence are summarized with advice to start these measures early in life, including maintaining a healthy body weight, increased levels of different types of physical activity, healthy eating and drinking, avoidance and cessation of smoking and alcohol use, management of stress and sleep levels. We also discuss the relevance of specific approaches including consumption of sodium, potassium, sugar, fibre, coffee, tea, intermittent fasting as well as integrated strategies to implement these recommendations using, for example, behaviour change-related technologies and digital tools.

Cardiovascular remodeling in active and controlled acromegaly: association with sleep-disordered breathing

PURPOSE

We hypothesized that an unfavorable cardiovascular profile in acromegaly is associated with sleep-disordered breathing (SDB), while acromegaly control improves both respiratory sleep characteristics and the cardiovascular profile.

METHODS

The patients underwent the assessment of breathing during sleep and cardiovascular profile assessment at the start of the study including arterial stiffness, blood pressure, echocardiography, nocturnal heart rate variability (HRV). The assessment was repeated in patients with acromegaly at 1 year after transsphenoidal adenectomy (TSA).

RESULTS

A total of 47 patients with acromegaly and 55 control subjects were enrolled. At one year after TSA, 22 patients with acromegaly were reassessed. Multiple linear regression analysis with adjustment for age, sex and body mass index (BMI) showed the associations of insulin growth-like factor 1 (IGF-1) with obstructive apnea index (OAI: β=0.035/h, p<0.001), but not with cardiovascular parameters, in patients with acromegaly. The analysis of combined acromegaly and control dataset with adjustment for age, sex and BMI showed the association the presence of acromegaly with diastolic blood pressure (DBP; β=17.99 mmHg, p<0.001), ejection fraction (EF; β=6.23%, p=0.009), left heart remodeling (left ventricle posterior wall: β=0.81 mm, p=0.045) and the association of the presence of SDB (apnea-hypopnea index≥15/h) with left ventricular function (EF: -4.12%, p=0.040; end systolic volume: 10.12 ml, p=0.004). Control of acromegaly was accompanied by the decrease in OAI (5.9 [0.8, 14.5]/h and 1.7 [0.2, 5.1]/h, p=0.004) and nocturnal heart rate (66.1 [59.2, 69.8] bpm and 61.7 [54.0, 67.2] bpm, p=0.025) and by the increase in blood pressure (DBP: 78.0 [70.3, 86.0] mm Hg and 80.0 [80.0, 90.0] mm Hg, p=0.012).

CONCLUSION

The comorbidities of acromegaly, including sleep-disordered breathing, appear to have a long-term effect on cardiovascular remodeling in active acromegaly. Future studies should investigate the applicability of the treatment of SDB for the reduction of cardiovascular risk in acromegaly.

Sleep-Disordered Breathing and Prognosis after Ischemic Stroke: It Is Not Apnea-Hypopnea Index That Matters

BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent after stroke and is considered to be a risk factor for poor post-stroke outcomes. The aim of this observational study was to evaluate the effect of nocturnal respiratory-related indices based on nocturnal respiratory polygraphy on clinical outcomes (including mortality and non-fatal events) in patients with ischemic stroke.

METHODS

A total of 328 consecutive patients (181 (55%) males, mean age 65.8 ± 11.2 years old) with confirmed ischemic stroke admitted to a stroke unit within 24 h after stroke onset were included in the analysis. All patients underwent standard diagnostic and treatment procedures, and sleep polygraphy was performed within the clinical routine in the first 72 h after admission. The long-term outcomes were assessed by cumulative endpoint (death of any cause, new non-fatal myocardial infarction, new non-fatal stroke/transient ischemic attack, emergency revascularization, emergency hospitalization due to the worsening of cardiovascular disease). A Cox-regression analysis was applied to evaluate the effects of nocturnal respiratory indices on survival.

RESULTS

The mean follow-up period comprised 12 months (maximal-48 months). Patients with unfavourable outcomes demonstrated a higher obstructive apnea-hypopnea index, a higher hypoxemia burden assessed as a percent of the time with SpO₂ < 90%, a higher average desaturation drop, and a higher respiratory rate at night. Survival time was significantly lower (30.6 (26.5; 34.7) versus 37.9 (34.2; 41.6) months (Log Rank 6.857, p = 0.009)) in patients with higher hypoxemia burden (SpO₂ < 90% during ≥2.1% versus <2.1% of total analyzed time). However, survival time did not differ depending on the SDB presence assessed by AHI thresholds (either ≥5 or ≥15/h). The multivariable Cox proportional hazards regression (backward stepwise analysis) model demonstrated that the parameters of hypoxemia burden were significantly associated with survival time, independent of age, stroke severity, stroke-related medical interventions, comorbidities, and laboratory tests.

CONCLUSION

Our study demonstrates that the indices of hypoxemia burden have additional independent predictive value for long-term outcomes (mortality and non-fatal cardiovascular events) after ischemic stroke.

The Prognostic Role of Polysomnography Parameters in Heart Failure Patients with Previous Decompensation

Background: Sleep-disordered breathing (SDB) is a widespread comorbidity in patients with chronic heart failure (HF) and may have a deleterious effect on the pathogenesis of HF. We aimed to evaluate the prognostic role of polysomnography parameters in HF patients with previous decompensation. Methods: 123 patients were included in the prospective cohort study. In addition to the standard examination, all patients underwent polysomnography (PSG). Results: The Kaplan−Meier analysis showed the incidence of the combined endpoint differs between LVEF categories ≤25.5% vs. >25.5% (χ2 = 9.6, log rank p = 0.002), NTpro-BNP > 680 vs. ≤680 pg/mL (χ2 = 12.7, log rank p = 0.001), VO2peak categories <16 vs. ≥16 mL/min/kg (χ2 = 14.2, log rank p = 0.001), VE/VCO2 slope ≥38.5 vs. <38.5 (χ2 = 14.5, log rank p = 0.001), wake after sleep onset >40 min vs. ≤40 min (χ2 = 9.7, log rank p = 0.03), and sleep stage 2 (S2) <44% vs. ≥44% (χ2 = 12.4, log rank p = 0.001). Conclusion: Among the PSG parameters, WASO > 40 min and S2 < 44% were associated with a combined endpoint in patients with previous decompensation of HF. Moreover, higher NT-proBNP and VE/VCO2 slope, lower LVEF, and VO2peak were also independent factors of a poor prognosis.

Compelled dichotomy of the cardiology training during COVID-19 time: green flag to the distant technologies

Background

The COVID-19 pandemic has dramatically influenced healthcare systems as well as the training environment worldwide. Numerous concerns have been raised about the disruption of cardiology training due to the social and physical distancing. We aimed to characterize the changes made in cardiology training in response to the COVID-19 pandemic and the personal perception of the new educational realities amongst first-year residents of the university clinic of the national medical research centre.

Methods

The institutional educational program underwent urgent and significant adaptation. Functions of the e-learning platform were extended in the purpose of the accumulation of the recorded lectures, online discussions, meetings, case-based clinical scenarios, virtual simulations, and regular virtual clinical rounds 2 times per week. Using an online 7-items survey, we analyzed the practical experience of 33 clinical cardiology trainees who worked within “red” and “green” zones and their personal perception of the distance educational technologies.

Results

At the peak of the pandemic outbreak, 40.6% of the residents have transferred into facilities restructured for COVID-19 patients for a median of 3 (1; 4) months. According to the responses they did not experience changes in the direct supervision time by their trainers and have achieved a higher level of independence in the procedural activity (arterial and central venous catheterization, CPR, performing intubation and invasive ventilation), decision making (such as prescription of anticoagulants and antibiotics, treatment of comorbid conditions), interpretation of the laboratory (acid-base balance, markers of myocardial, kidney and liver damage) and instrumental findings (ECG, echocardiography, coronary tomography). Despite the challenges, 75% of the trainees positively assessed their training in infectious settings.

Due to the accidental contacts with COVID-19 patients and the associated need for 14-days quarantine residents who remained in the “green” zone experienced a reduction in direct supervision time from 57 to 17 hours per week (−70%) and were lack of procedural skills improvement. However, using the wide range of the educational resources provided in demand resulted in an increase in their learning time (plus 8 hours per week) with improvement in cardiology knowledge. Positive feedback was received from 85% of these residents with mention of the improvement of self-management.

Conclusions

Despite worldwide adoption of the educational program to the distant learning cardiology residents can experience different educational scenarios in the different setting due to COVID-19 cases surge. Combination of direct supervision, teaching remotely with staff support, case-based discussions, wider use of simulation, telemedicine, and social media engagement are urgently needed for adaptation of the educational programs in order to reduce the continuing shortage of specialists.

Funding Acknowledgement

Type of funding sources: None.

Ischemic Stroke and Sleep: The Linking Genetic Factors

This review summarizes the available data about genetic factors which can link ischemic stroke and sleep. Sleep patterns (subjective and objective measures) are characterized by heritability and comprise up to 38-46%. According to Mendelian randomization analysis, genetic liability for short sleep duration and frequent insomnia symptoms is associated with ischemic stroke (predominantly of large artery subtype). The potential genetic links include variants of circadian genes, genes encoding components of neurotransmitter systems, common cardiovascular risk factors, as well as specific genetic factors related to certain sleep disorders.

Sleep and Cardiovascular Risk

Sleep is essential for healthy being and healthy functioning of human body as a whole, as well as each organ and system. Sleep disorders, such as sleep-disordered breathing, insomnia, sleep fragmentation, and sleep deprivation are associated with the deterioration in human body functioning and increased cardiovascular risks. However, owing to the complex regulation and heterogeneous state sleep per se can be associated with cardiovascular dysfunction in susceptible subjects. The understanding of sleep as a multidimensional concept is important for better prevention and treatment of cardiovascular diseases.

Pulse wave velocity is decreased in acromegaly compared to non-acromegaly study participants with similar cardiovascular risk profile

OBJECTIVE

Acromegaly patients were reported to have an increased arterial stiffness that could contribute to the frequent cardiovascular complications in this population. The chronic excess of GH and IGF-1 may lead to arterial stiffening via different mechanisms, including hypertension, impaired glucose tolerance and dyslipidemia, however, it is not known whether the activation of GH/IGF-1 axis might influence arterial stiffening independently of cardiovascular risk factors. The objective of this prospective case-control study was to compare arterial stiffness assessed with pulse-wave velocity (PWV) in acromegaly versus non-acromegaly group with similar cardiovascular risk profile.

DESIGN

This prospective case-control study included 27 patients with active acromegaly, who underwent the assessment of clinical, physiological, biochemical parameters and the evaluation of PWV with applanation tonometry. We used "The epidemiology of cardiovascular disease in different regions of the Russian Federation" study database (n = 522) to establish a non-acromegaly control group with similar cardiovascular risk profile (n = 54). Non-acromegaly control participants underwent the same assessment as acromegaly patients except for the measurement of serum GH and IGF-1 levels. We compared PWV in acromegaly patients to the general non-acromegaly cohort and its subset, matched with acromegaly patients for cardiovascular risk factors. We also investigated the associations of PWV with clinical, physiological and biochemical parameters in acromegaly and non-acromegaly group using correlation and regression analysis with adjustment for age and sex.

RESULTS

Acromegaly patients had lower PWV (6.70 (5.75-7.65) m/s) compared to unmatched non-acromegaly control cohort (7.50 (6.70-8.57) m/s, p = 0.01) and to the non-acromegaly control group matched for cardiovascular risk factors (7.45 (6.73-8.60), p < 0.01). In non-acromegaly control group PWV was associated with BMI (ρ = 0.40, p < 0.01; β = 0.09, p < 0.01), obesity (r = 0.46, p < 0.01; β = 1.36, p < 0.01), systolic blood pressure (ρ = 0.60, p < 0.01; β = 0.05, p < 0.01), diastolic blood pressure (ρ = 0.62, p < 0.01; β = 0.07, p < 0.01), triglycerides (ρ = 0.55, p < 0.01; β = 0.58, p = 0.04), glucose (ρ = 0.54, p < 0.01; β = 0.70, p < 0.01) and diabetes (r = 0.40, p < 0.01; β = 1.10, p = 0.03), while in acromegaly group PWV was associated with IGF-1 expressed in mcg/ml (ρ = -0.49, p ≤0.01; β = -0.002, p ≤0.01) and in percentage of the upper limit of the normal (ρ = -0.47, p = 0.01; β = -0.005, p ≤0.01) as well as with diuretics treatment (β = -1.17, p = 0.03).

CONCLUSIONS

PWV is decreased in acromegaly patients compared to non-acromegaly control participants with similar cardiovascular risk profile. Future studies need to explore the role of GH/IGF-1 axis in the regulation of arterial wall properties and the reliability of PWV as a prognostic marker of cardiovascular complications in acromegaly.

Effect of early sleep apnoea treatment with adaptive servo-ventilation in acute stroke patients on cerebral lesion evolution and neurological outcomes: study protocol for a multicentre, randomized controlled, rater-blinded, clinical trial (eSATIS: early Sleep Apnoea Treatment in Stroke)

BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent in acute ischaemic stroke and is associated with worse functional outcome and increased risk of recurrence. Recent meta-analyses suggest the possibility of beneficial effects of nocturnal ventilatory treatments (continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV)) in stroke patients with SDB. The evidence for a favourable effect of early SDB treatment in acute stroke patients remains, however, uncertain.

METHODS

eSATIS is an open-label, multicentre (6 centres in 4 countries), interventional, randomized controlled trial in patients with acute ischaemic stroke and significant SDB. Primary outcome of the study is the impact of immediate SDB treatment with non-invasive ASV on infarct progression measured with magnetic resonance imaging in the first 3 months after stroke. Secondary outcomes are the effects of immediate SDB treatment vs non-treatment on clinical outcome (independence in daily functioning, new cardio-/cerebrovascular events including death, cognition) and physiological parameters (blood pressure, endothelial functioning/arterial stiffness). After respiratory polygraphy in the first night after stroke, patients are classified as having significant SDB (apnoea-hypopnoea index (AHI) > 20/h) or no SDB (AHI < 5/h). Patients with significant SDB are randomized to treatment (ASV+ group) or no treatment (ASV- group) from the second night after stroke. In all patients, clinical, physiological and magnetic resonance imaging studies are performed between day 1 (visit 1) and days 4-7 (visit 4) and repeated at day 90 ± 7 (visit 6) after stroke.

DISCUSSION

The trial will give information on the feasibility and efficacy of ASV treatment in patients with acute stroke and SDB and allows assessing the impact of SDB on stroke outcome. Diagnosing and treating SDB during the acute phase of stroke is not yet current medical practice. Evidence in favour of ASV treatment from a randomized multicentre trial may lead to a change in stroke care and to improved outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02554487 , retrospectively registered on 16 September 2015 (actual study start date, 13 August 2015), and www.kofam.ch (SNCTP000001521).

Sleep-related breathing disorders in patients with pulmonary hypertension

Introduction

There are some evidences of sleep-related breathing disorders (SRBD) association with pulmonary hypertension (PH). Only limited information regarding the SRBD prevalence in pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) patients, is available.

Purpose

To estimate the features of SRBD and the asymmetric dimethylarginine (ADMA) level in PAH and CTEPH patients and their relationship with the severity of PH.

Methods

There were included 31 patients (45% male; 55% female) with a verified diagnosis of precapillary PH: 22.6% – with PAH; 9,7% with PAH associated with adult congenital heart disease; 64.5% – with CTEPH; 3.2% with PAH associated with connective tissue disease. Patients underwent a general clinical examination, questionnaires, a comprehensive assessment of respiratory function, a complete polysomnographic study, ECG and ECHO studies, assessment of clinical and biochemical blood tests, including an assessment of ADMA and NT-proBNP levels.

Results

SRBD of a predominantly obstructive nature were found in 74.2% of the examined: 38.7% were mild, 22.6% were moderate, 12.9% were severe. In 35% of patients, episodes of periodic breathing during sleep were recorded. There was no association SRBD with PH functional class and hemodynamic parameters. Moderate correlation was observed between the apnea-hypopnea index and remodeling indices of the heart chambers according to ECHO: for the end-diastolic size of the left ventricle (ρ=0.54; p=0.005); for an indicator of the ratio of the size of the ventricles (RV/LV) (ρ=−0.41, p=0.05). The presence of SRBD wasn't associated with the level of peripheral blood saturation according to pulse oximetry in sleep and during wakefulness. Negative moderate correlation was observed between NT-proBNP level and the average peripheral blood saturation at night in the entire examined group (ρ=−0.40; p=0.035). All patients showed an increase in ADMA, with no association between ADMA and SRBD severity.

Conclusions

The incidence of SRBD is extremely high in PAH and CTEPH patients. However, there no association between presence and severity of PH, including with right heart remodeling. But the severity of nocturnal hypoxemia is associated with an increase in NT-proBNP level, a proven marker of poor prognosis in PAH and CTEPH groups of patients. SRBD severity indices (apnea-hypopnea index and desaturation index) are associated with ECHO parameters characterizing remodeling of left heart chambers. Increasing ADMA level as a marker of endothelial dysfunction was related with PH severity, but not with SRBD.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Almazov National Medical Research Centre

P1554Is self-reported sleep-disordered breathing associated with increased cardiovascular risk?

Background

Sleep-disordered breathing (SDB) is associated with the increased cardiovascular (CV) morbidity and mortality. However, sleep apnea is not considered in the standard scales used for the risk stratification.

Purpose

We evaluated the association between self-reported SDB and SCORE risk (the 10-year risk of fatal CV events according to the systemic coronary risk evaluation) in the population-based sample from St Petersburg.

Methods

We selected 1555 subjects without previously known CV events (550 males, 35%; mean age 46.7±11.6 years old) out of 1600 participants of the population-based sample (from the epidemiological study ESSE-RF, St Petersburg). All subjects were interviewed (questions about lifestyle, medical history, complaints) using standard questionnaire. We assessed self-reported snore (“Do you snore?”) and sleep apnea (“Do you have sleep apneas?”). Affirmative response was considered diagnostic. Daytime sleepiness was assessed based on the answers >3 times/week to the question “How often have you been unable to refrain sleeping when required?”. The 10-year risk of fatal CV events was assessed by the SCORE high-risk charts calculator. For statistical analysis we used parametric statistics, frequency and contingency analyses (Chi-square), multiple logistic regression analysis (stepwise inclusion; the parameters not evaluated in the SCORE scale were considered, i.e. body mass index, glucose level, triglyceride, HDL-cholesterol, creatinine, C-reactive protein, self-reported insomnia).

Results

Based on the SCORE assessment the participants were divided as following: low risk (<1%) was the most predominant category (n=864, 55.6%); moderate risk (≥1% and <5%) was found in 468 (30.1%), high risk (5–10%) – in 184 (11.8%), and very high risk – in 39 (2.5%) subjects. In total, 740 (47.6%) subjects had snoring, while only 77 (5%) subjects reported sleep apneas. Neither self-reported snoring nor sleep apnea were associated with daytime sleepiness (p>0.05). High-to-very-high SCORE risk was found more often in subjects with self-reported snoring compared to non-snorers: 21.2% vs. 8.1%, respectively (Chi-square=54.3, p<0.001). At the same time no association was found between self-reported sleep apneas and cardiovascular risk. Logistic regression demonstrated an association between SCORE risk and self-reported snoring (OR=3.06 95% CI 2.25–4.16, p<0.001). Multiple regression analysis confirmed the impact of snoring in the increased SCORE risk (OR=2.16 95% CI 1.55–3.02, p<0.001) after adjustment for the other factors.

Conclusions

Our study demonstrated that in Russian population-based sample self-reported snoring (unlike self-reported sleep apnea) is associated with the increased 10-year risk of fatal CV events. The lack of association between SCORE risk and sleep apnea might be related to the subjective assessment based on the questionnaire.

Acknowledgement/Funding

The study was supported by the Grant of the President of Russian Federation for the Leading Scientific Schools of Russia (agreement No. 075-02-2018-57,

Prevalence of sleep-disordered breathing after stroke and TIA: A meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis on the prevalence of sleep-disordered breathing (SDB) after stroke.

METHODS

We searched PubMed, Embase (Ovid), the Cochrane Library, and CINAHL (from their commencements to April 7, 2017) for clinical studies reporting prevalence and/or severity of SDB after stroke or TIA. Only sleep apnea tests performed with full polysomnography and diagnostic devices of the American Academy of Sleep Medicine categories I-IV were included. We conducted random-effects meta-analysis. PROSPERO registration number: CRD42017072339.

RESULTS

The initial search identified 5,211 publications. Eighty-nine studies (including 7,096 patients) met inclusion criteria. Fifty-four studies were performed in the acute phase after stroke (after less than 1 month), 23 studies in the subacute phase (after 1-3 months), and 12 studies in the chronic phase (after more than 3 months). Mean apnea-hypopnea index was 26.0/h (SD 21.7-31.2). Prevalence of SDB with apnea-hypopnea index greater than 5/h and greater than 30/h was found in 71% (95% confidence interval 66.6%-74.8%) and 30% (95% confidence interval 24.4%-35.5%) of patients, respectively. Severity and prevalence of SDB were similar in all examined phases after stroke, irrespective of the type of sleep apnea test performed. Heterogeneity between studies (I ²) was mostly high.

CONCLUSION

The high prevalence of SDB after stroke and TIA, which persists over time, is important in light of recent studies reporting the (1) feasibility and (2) efficacy of SDB treatment in this clinical setting.

Sleep architecture measurement based on cardiorespiratory parameters

This paper presents a method for the detection of wakeful state, rapid eye movement sleep (REM), light sleep (N1&N2) and deep sleep (N3&N4) based on cardiorespiratory parameters. Experiments were conducted with data of 625 subjects without sleep-disordered breathing selected from the SHHS dataset. Compared to previous studies, our method considers results of neighboring epochs classification and epoch position over record time. The method demonstrates Cohen's kappa of 0.57 ± 0.13 and the accuracy of 71.4 ± 8.6 %. The results might contribute to the development of screening tools for diagnostics, prevention, and management of sleep disorders.

Estimation of a priori probabilities of sleep stages: A cycle-based approach

This paper presents a model for the estimation of a priori probabilities of sleep epoch classes based on the epoch location in a sleep cycle. These probabilities are used as additional features for sleep stage classification based on the analysis of respiratory effort. The model was validated with data of 685 subjects selected from the Sleep Heart Health Study dataset. The model improves a base algorithm by 8 percent points and demonstrates Cohen's kappa of 0.56 ± 0.12. Our results will contribute to the development of screening tools for unobtrusive sleep structure estimation.

Sleep-disordered breathing: clinical features, pathophysiology and diagnosis

In recent decades, the association between sleep-disordered breathing (SDB) and cardio- and cerebrovascular diseases (including hypertension, coronary heart disease and stroke) has been the focus of interest of both clinicians and researchers. A growing concern is the increasing prevalence of SDB in the general population, which can be partly explained by the rise in obesity prevalence and population aging, as well as by the development of enhanced diagnostic tools and approaches. Because of evidence of adverse long-term effects of SDB on cardiovascular morbidity and overall mortality, systematic screening for SDB should be considered for populations at risk. The evidence of a long-term benefit of treatment for SDB, however, is still controversial and the best management approaches are still unclear. This article summarises available epidemiological data and focuses on the main pathophysiological mechanisms linking SDB to cardio- and cerebrovascular disorders. We will also give a critical overview of the current diagnostic procedures. The available treatment approaches and their prognostic effects on cardio- and cerebrovascular health will be discussed in a second paper.

Sleep stage classification based on respiratory signal

One of the research tasks, which should be solved to develop a sleep monitor, is sleep stages classification. This paper presents an algorithm for wakefulness, rapid eye movement sleep (REM) and non-REM sleep detection based on a set of 33 features, extracted from respiratory inductive plethysmography signal, and bagging classifier. Furthermore, a few heuristics based on knowledge about normal sleep structure are suggested. We used the data from 29 subjects without sleep-related breathing disorders who underwent a PSG study at a sleep laboratory. Subjects were directed to the PSG study due to suspected sleep disorders. A leave-one-subject-out cross-validation procedure was used for testing the classification performance. The accuracy of 77.85 ± 6.63 and Cohen's kappa of 0.59 ± 0.11 were achieved for the classifier. Using heuristics we increased the accuracy to 80.38 ± 8.32 and the kappa to 0.65 ± 0.13. We conclude that heuristics may improve the automated sleep structure detection based on the analysis of indirect information such as respiration signal and are useful for the development of home sleep monitoring system.

Bioradiolocation-based sleep stage classification

This paper presents a method for classifying wakefulness, REM, light and deep sleep based on the analysis of respiratory activity and body motions acquired by a bioradar. The method was validated using data of 32 subjects without sleep-disordered breathing, who underwent a polysomnography study in a sleep laboratory. We achieved Cohen's kappa of 0.49 in the wake-REM-light-deep sleep classification, 0.55 for the wake-REM-NREM classification and 0.57 for the sleep/wakefulness determination. The results might be useful for the development of unobtrusive sleep monitoring systems for diagnostics, prevention, and management of sleep disorders.

Sleep stage classification based on bioradiolocation signals

This paper presents an algorithm for the detection of wakeful state, rapid eye movement sleep (REM) and non-REM sleep based on the analysis of respiratory movements acquired through a bioradar. We used the data from 29 subjects without sleep-related breathing disorders who underwent a polysomnography study at a sleep laboratory. A leave-one-subject-out cross-validation procedure was used for testing the classification performance. Cohen's kappa of 0.56 ± 0.16 and accuracy of 75.13 ± 9.81 % were achieved when compared to polysomnography results. The results of our work contribute to the development of home sleep monitoring systems.

Sleep-disordered breathing: clinical features, pathophysiology and diagnosis

In recent decades, the association between sleep-disordered breathing (SDB) and cardio- and cerebrovascular diseases (including hypertension, coronary heart disease and stroke) has been the focus of interest of both clinicians and researchers. A growing concern is the increasing prevalence of SDB in the general population, which can be partly explained by the rise in obesity prevalence and population aging, as well as by the development of enhanced diagnostic tools and approaches. Because of evidence of adverse long-term effects of SDB on cardiovascular morbidity and overall mortality, systematic screening for SDB should be considered for populations at risk. The evidence of a long-term benefit of treatment for SDB, however, is still controversial and the best management approaches are still unclear. This article summarises available epidemiological data and focuses on the main pathophysiological mechanisms linking SDB to cardio- and cerebrovascular disorders. We will also give a critical overview of the current diagnostic procedures. The available treatment approaches and their prognostic effects on cardio- and cerebrovascular health will be discussed in a second paper.

Is Mixed Apnea Associated with Non-Rapid Eye Movement Sleep a Reversible Compensatory Sign of Heart Failure?

Patient: Male, 24

Final Diagnosis: Dilated cardiomyopathy

Symptoms: Biventricular heart failure • sleep apnea

Medication: —

Clinical Procedure: Heart transplantation

Specialty: Cardiology

New insights into the management of rhythm and conduction disorders after acute myocardial infarction

PATIENT

Male, 53 FINAL DIAGNOSIS: Myocardial infarction Symptoms: Chest pain • tachycardia

MEDICATION

- Clinical Procedure: - Specialty: Cardiology.

OBJECTIVE

Challenging differential diagnosis.

BACKGROUND

Comorbidities, including obesity and sleep-breathing disorders, can adversely influence outcomes in acute myocardial infarction (AMI), and should be considered in diagnosis and treatment administration.

CASE REPORT

The case demonstrates the difficulties of treating a middle-aged Caucasian patient with multiple comorbidities that could be overcome by a personalized approach and evaluation of concomitant sleep-breathing disorders (by polysomnography study). Diagnosis and treatment of sleep apnea by positive airway pressure (PAP therapy) played a pivotal role in heart rate and rhythm control.

CONCLUSIONS

In this case, effective PAP therapy enabled titration of antiarrhythmic drugs (to maximal doses) to achieve heart rate control and to eliminate severe ventricular tachyarrhythmias and contributed to the better recovery in a post-AMI patient with left ventricular systolic dysfunction.