Aim. To compare the clinical characteristics of two groups of patients with a combination of obstructive sleep apnea (OSA) and paroxysmal atrial fibrillation (AF), undergoing conservative treatment for arrhythmia and after pulmonary vein isolation.Material and methods. The study included 362 patients with paroxysmal AF who underwent respiratory sleep monitoring.Results. A predominance of clinically significant OSA was revealed (moderate and severe — 37% and 29%, respectively), as well as a higher drug burden and comorbidity in the group of patients receiving drug treatment for AF. The threshold value of body mass index (BMI), at which a high risk of severe OSA was predicted, corresponded to class 1 obesity (BMI ≥31 kg/m2). The results obtained demonstrated an association between an increase in the left atrium anteroposterior size and the severity of OSA (4,1 [3,8-4,4] cm, r=0,28; p<0,001), which may be due to cardiac structural remodeling in patients with a combination of paroxysmal AF and severe OSA.Conclusion. In a cohort of patients with paroxysmal AF, a high incidence of clinically significant OSA was revealed. In the group of patients with a combination of OSA and AF undergoing conservative treatment, more unfavorable cardiovascular characteristics and a more severe comorbid status were revealed compared to the group of patients undergoing surgical treatment.

Создание руководства поддержано Советом по терапевтическим наукам отделения клинической медицины Российской академии наук.

Aim. To identify and study the nature of sleep-related breathing disorders (SBDs) in a cohort of hospitalized patients with heart failure (HF) with reduced and mildly reduced ejection fraction (EF), as well as to clarify the relationship between SBD type, etiology and severity of HF. Material and methods. The study included 117 patients with HF with reduced and mildly reduced ejection fraction hospitalized at the National Medical Research Center for Therapy and Preventive Medicine from 2019 to 2021. All patients underwent clinical and paraclinical examination, including cardiorespiratory sleep study. Patients were divided into three groups according to the type and severity of SBD: no or mild SBD, predominantly with obstructive sleep apnea (OSA) and predominantly with central sleep apnea (CSA). Severity of SBD and clinical data were compared between these groups. Results. A total of 5 patients (4,27%) did not have any SBDs, while 47 (40,17%) were diagnosed with CSA, and 65 (55,56%) — OSA of varying severity. The proportions of patients with moderate and severe CSA and OSA differed insignificantly and amounted to 35,9% (n=42) and 44,4% (n=52), respectively. There were following proportions of diseases related to HF: coronary artery disease (41,88%), nonischemic cardiomyopathy (26,5%), arrhythmogenic cardiomyopathy (15,38%) and other causes (16,24%) (hypertension, myocarditis, heart defects). We found that reduced EF <40%, end-diastolic volume >210 ml, and ventricular ectopy (>300 extrasystoles/day) were associated with CSA, and body mass index >30 kg/m 2 was traditionally associated with OSA. Conclusion. More than half of HF patients with reduced and mildly reduced EF have SBDs. Decreased LVEF and ventricular ectopic activity are associated with CSA, while increased body mass index is associated with OSA. Consideration of SBD risk factors may improve patient phenotyping for individualized therapy.

Review of the article Medvedeva E. A., Korostovtseva L. S., Bochkarev M. V., Sazonova Yu. V., Sviryaev Yu. V. Clinical and prognostic role of sleep-related breathing disorders in patients with heart failure depending on body mass index. Russian Journal of Cardiology. 2023;28(3):5263. doi:10.15829/1560-4071-2023-5263. EDN LWBNSN

The aim of the present research was to examine the electrical activity of the brain on polysomnographic recordings using a new approach of oscillatory wavelet patterns. This study has shown that EEG signals recorded in the REM stage of sleep have specific oscillatory characteristics in the band 20-40 Hz, which make it possible to statistically reliably distinguish this stage of sleep both from other stages of sleep and from wakefulness. Keywords: continuous wavelet analysis, polysomnography, sleep stages.

Aim. To study the isolated effect of obstructive sleep apnea (OSA) on left atrial (LA) remodeling in patients with paroxysmal atrial fibrillation (AF) who underwent pulmonary vein (PV) ablation and concomitant severe and moderate OSA.Material and methods. A subanalysis of echocardiographic data was performed in 50 patients with paroxysmal AF and moderate/severe OSA who underwent PV isolation and were followed up for 12 months (main group, 33; control group, 17). The clinical efficacy of catheter ablation was assessed after the end of the threemonth blind period. The following echocardiographic parameters were included in the subanalysis: anterior-posterior LA dimension, LA volume, LA volume index (LAVI), and pulmonary artery systolic pressure (PASP).Results. After 12 months, the control group showed a significant increase in the anterior-posterior LA dimension (40,5 (40-42) mm vs 42 (40-45) mm, p=0,037), LA volume (68,5 (58-74,5) ml vs 69 (63-89) ml, p=0,006), LAVI (35,0 (29-37) ml/m2 vs 35,5 (32-41,5) ml/m2, p=0,005) and PASP (27 (25-30) vs 30 (29-33), p=0,004). Intragroup analysis of patients not receiving continuous positive airway pressure (CPAP) therapy and without recurrent AF did not reveal significant changes in LA size (anterior-posterior LA dimension — 40 (40-42) mm vs 40 (40- 41) mm, p=0,317; LA volume — 63 (58-71) ml vs 64 (61-69) ml, p=0,509; LAVI — 32 (29-36) ml/m2 vs 33 (31-34) ml2, p=0,509).Conclusion. In patients with paroxysmal AF and concomitant moderate to severe OSA who underwent AF catheter treatment, the absence of CPAP therapy is not associated with a significant increase in the linear and volume LA dimensions in the absence of AF recurrence.

The second part of the review highlights treatments for different types of sleep apnea in patients with heart failure. In both obstructive and central sleep apnea, ventilatory support during sleep takes a special place in treatment. Therefore, the review details the role of different ventilation modes (in particular, CPAP therapy and adaptive servo-ventilation), analyzes available evidence-based medicine data. The role of low-flow oxygen therapy, surgical treatment, implantable devices, specific therapy (theophylline, acetazolamide) in the treatment of central sleep apnea is also shown, and a novel method of treating central sleep apnea is considered — phrenic nerve stimulation.

This review examines in detail the mechanisms of cardiovascular autonomic control in the course of sleep, during single and multiple repetitive episodes of apnea, their role in pathogenesis of atrial fi brillation (AF), and also highlights the methods of autonomic modulation. In conditions of a single or chronic exposure to obstructive sleep apnea, cardiovascular autonomic dysfunction is one of the leading factors providing the possibility of AF development and recurrence. A combined effect on AF risk factors (their modifi cation, use of continuous positive airway pressure therapy, drug therapy, and interventional techniques) can normalize the autonomic control and positively affect the substrate leading to the development and progression of arrhythmia.

Установлено, что короткая продолжительность сна ассоциирована с развитием сердечно-сосудистых заболеваний и метаболических нарушений, а также увеличивает смертность от всех причин. В представленном обзоре даны определения границ короткого сна, частичной и полной депривации сна, освещены патофизиологические механизмы, которые могут быть запущены при продолжительности сна менее 6 часов, оценены влияния экспериментальных типов сокращения сна, а также короткой продолжительности сна на развитие тех или иных сердечно-сосудистых заболеваний.

The article presents an observation of a rare clinical arrhythmia — REM-associated advanced atrioventricular block 2nd degree. The absence of structural abnormalities of the heart, the young age and the need for additional methods of instrumental examination for diagnosis (polysomnography, test with the active orthostasis test) are important features of the case. Despite the orphan nature of this arrhythmia, the correct diagnosis is important for the choice of the management strategy choice.

Aim. To assess the effect of withdrawing long-term (12 months) CPAP therapy on the course of obstructive sleep apnea (OSA) in patients with moderate to severe disease.Material and methods. The study included 40 patients with moderate to severe OSA and paroxysmal atrial fibrillation (AF) after surgical treatment. The mean age of the subjects was 59,3+8,2 years. In addition, 55% of patients had obesity. All patients were started on CPAP therapy. After 12 months, CPAP therapy was canceled in the patients who completed the study. Additional cardiorespiratory sleep monitoring was performed 1-2 days after the withdrawal of treatment to assess the severity of sleep-related breathing disorders.Results. Cancellation of CPAP therapy in all observed cases led to an immediate relapse of OSA. Although the mean value of the apnea/hypopnea index (AHI) decreased from 24 episodes per hour [20; 34] before treatment up to 21 episodes per hour [13; 27] after 12-month CPAP therapy, there was no significant difference before and after therapy. In addition, the statistical analysis showed a transition from more severe OSA degrees to moderate ones, depending on the initial severity of the disease. Correlation analysis demonstrated significant relationships of the OSA severity, the final AHI value and the minimum oxygen level with the patient’s body weight (before and after therapy) (r=0,396, 0,411 and -0,488; r=0,358, 0,398 and -0,44, respectively, p<0,05).Conclusion. In our study, when the 12-month CPAP therapy was canceled, no complete cure for sleep-related breathing disorders was recorded in any case. OSA recurrence was recorded immediately after discontinuation of CPAP therapy (on days 1-2) and its severity depended on the initial severity of the disease. At present, the continuation of CPAP therapy remains the only way to achieve complete control of OSA as a risk factor for AF.

Obstructive sleep apnea (OSA) is associated with many cardiovascular and metabolic diseases. Sleep apnea causes intermittent hypoxemia, chest pressure fluctuations and a reaction from the cerebral cortex in the form of a short awakening during sleep (EEG-activation). The consequences of pathological pathways are studied in experimental models involving cell cultures, animals, and healthy volunteers. At present, the negative impact of intermittent hypoxemia on a variety of pathophysiological disorders of the heart and blood vessels (vascular tone fluctuations, thickening of the intimamedia complex in the vascular wall, direct damaging effect on the myocardium) has a great evidence base. Two other pathological components of OSA (pressure fluctuations and EEG-activation) can also affect cardiovascular system, mainly affecting the increase in blood pressure and changing cardiac hemodynamics. Although these reactions are considered separately in the review, with the development of sleep apnea they occur sequentially and are closely interrelated. As a result, these pathological pathways trigger further pathophysiological mechanisms acting on the heart and blood vessels. It is known that these include excessive sympathetic activation, inflammation, oxidative stress and metabolic dysregulation. In many respects being links of one process, these mechanisms can trigger damage to the vascular wall, contributing to the formation of atherosclerotic lesions. The accumulated data with varying degrees of reliability confirm the participation of OSA through these processes in the formation of cardiovascular disorders. There are factors limiting direct evidence of this interaction (sleep deprivation, causing similar changes, as well as the inability to share the contribution of other risk factors for cardiovascular diseases, in particular arterial hypertension, obesity, which are often associated with OSA). It is necessary to continue the study of processes that implement the pathological effect of OSA on the cardiovascular system.

The problem of heart failure (HF) is one of the central problems in modern cardiology due to its high prevalence among the population and high mortality. In turn, sleep-related breathing disorders (SRBD) are widespread in patients with HF and are associated with both the progression of the underlying disease and a decrease in the quality of life. For the first time, periodic breathing, as one of the types of sleep breathing disorders, was described in patients with HF.Further study of the issue showed a high prevalence of other types of SRBD among patients with HF The article discusses the physiology of sleep breathing monitoring in a healthy person and the pathophysiology of SRBD. The pathogenesis of central sleep apnea and its relationship with HF are discussed in detail. In addition, the mechanisms of the adverse effect of obstructive sleep apnea and HF are highlighted.

Polysomnography and cardiorespiratory (respiratory) sleep monitoring are the most common diagnostic methods for respiratory sleep disorders. Polysomnography traditionally takes the place of the “gold” standard for detection of all types of respiratory events since its inception. Currently, cardiorespiratory monitoring of sleep is becoming more widespread as a diagnostic method with a minimum set of parameters for determining respiratory events during sleep. The increased use of cardiorespiratory (respiratory) monitoring of sleep is due to 2 reasons: the increased need for diagnosis due to the wide occurrence of respiratory disorders in the population and the conditions of the method (simple use, the need for a sleep laboratory, cheaper cost). However, the method is not indicated to all patients. Potential limitations for cardiorespiratory monitoring of sleep are the lack of sleep recording (information about the structure of sleep and reactions of sleep to respiratory disorders), monitoring of the study by medical personnel, and absence of body position sensor. These factors influence the assessment of the severity of the disease and the verification of certain forms of the disease. Currently, new methods of screening sleep apnea have been formed, based on modern innovative technologies and available in practical medicine. These include the determination of the presence of respiratory events be ECG Holter monitoring during sleep, the recognition of snoring and respiratory events in sleep from an audiometric signal recording and the determination of the probability of apnea with the help of registration movements during sleep (actigraphy).

The results of prospective studies, meta-analyzes and systematic reviews on the associations of obstructive sleep apnea (OSA) with various cardiovascular diseases (CVD) were analyzed. The second part is devoted to the analysis of the relationship between OSA and CVD such as coronary artery disease, cerebrovascular disease, heart failure, pulmonary hypertension. All of them are associated with breathing-related sleep disorders. Among these diseases, the most significant associations were revealed for OSA and heart failure, OSA and cerebrovascular disease. Separately, the relationship of OSA with cardiovascular mortality is discussed. Most observational studies have shown that OSA without treatment increases mortality rate.

The results of prospective studies, meta-analyzes and systematic reviews on the associations of obstructive sleep apnea (OSA) with various cardiovascular diseases (CVD) were analyzed. Currently, the mechanisms related to high prevalence of breathing-related sleep disorders among population of economically developed countries are clear, and an increase in the number of OSA patients has been shown. The relationship between OSA and CVD has been widely confirmed in large cohort studies. The first review part discusses the relationship of hypertension (HTN) and various heart arrhythmias (atrial fibrillation (AF), bradyarrhythmias, premature ventricular contraction, sudden death during sleep) with breathing-related sleep disorders. These groups of cardiovascular disorders currently show the most proven relationship with sleep apnea. In addition to cross-sectional studies indicating the high prevalence of OSA in patients with HTN and AF, some observational studies indicate an increase in the number of patients with HTN and paroxysmal AF with history of untreated sleep apnea. An analysis of the current issues of OSA phenotypes (in particular, REM-related OSA in hypertensive patients) as the most unfavorable cardiovascular factors is carried out.

Aim. To study the prevalence of obstructive sleep apnea (OSA) among patients with atrial fibrillation (AF) who have undergone catheter treatment for this arrhythmia, as well as to study the possible interrelationships of these sleep breathing disorders with comorbid diseases and the received therapy in this cohort.Material and methods. 231 patients from a random sample were examined (men – 118 [51.1%], mean age 57.8±9.3 years) in the range of 1-6 months after catheter therapy for AF. All patients underwent cardiorespiratory sleep monitoring for one night. The criterion for OSA severity was apnea/hypopnea index (AHI) for hour (the norm is less than 5 events/h). Depending on the results obtained, all patients were divided into groups without apnea and with apnea of varying severity – a mild degree with an AHI value of 5 to 15 events/h, moderate severity with an AHI value of 16 to 30 events/h, and severe degree when the value of AHI more than 30 events/h. The study was performed without abolishing the basic therapy.Results. According to the results of cardiorespiratory sleep monitoring 127 patients (56.7%) with OSA criteria, were registered. Among them, a mild degree of OSA was found in 35.4% (n=45), a moderate degree – in 40.9% (n=52), and severe one – in 23.7% (n=30) of all patients with apnea. Among patients with obstructive sleep apnea 51.1% were males. Arterial hypertension was significantly more frequent in patients with OSA of pronounced degrees of severity compared with patients without apnea (p=0.047). Weight and body mass index of patients with OSA were significantly higher than in patients without apnea (p=0.001 and p=0.001, respectively). The left atrium (LA) size in patients with severe OSA was significantly larger than in patients without apnea (p=0.0005), which may indicate a possible contribution of severe obstructive apnea to the arrhythmia generating. OSA was the strongest independent factor among others related to the LA size (odds ratio was 1.6; 95% confidence interval 1.2-2.1; p<0.0003).Conclusion. Obstructive sleep apnea is very widespread among a cohort of patients with AF who have undergone a catheter procedure to isolate the pulmonary veins. Sleep breathing disorder is the strongest and most independent risk factor for AF associated with increased LA, among other risk factors such as age, hypertension, and obesity.