Central sleep apnoea and inflammation are independently associated with arrhythmia in patients with heart failure

Nocturnal Cardiac Arrhythmias in Heart Failure With Obstructive and Central Sleep Apnea

BACKGROUND

Both OSA and central sleep apnea (CSA) may contribute to nocturnal cardiac arrhythmias (NCAs). Data are scarce regarding the prevalence of clinically important nocturnal atrial and ventricular arrythmias in patients with heart failure with reduced ejection fraction (HFrEF) and OSA or CSA.

RESEARCH QUESTION

In a cohort of patients with HFrEF, how does the prevalence of NCA compare among those with OSA, CSA, and those with no to mild sleep apnea? Is the severity of OSA or CSA associated with atrial and ventricular NCAs?

STUDY DESIGN AND METHODS

This cross-sectional analysis is an ancillary study of the Effect of Adaptive Servo Ventilation on Survival and Hospital Admissions in Heart Failure (ADVENT-HF) trial. We compared the prevalence of NCAs (excessive supraventricular ectopic activity [ESVEA], defined as premature atrial complexes ≥30/h or supraventricular tachycardia ≥ 20 beats); atrial fibrillation/flutter [AF]; and > 10 premature ventricular complexes [PVC/h]) on ECGs from polysomnograms of patients with HFrEF between those with OSA (apnea-hypopnea index [AHI ≥ 15 events/h]), those with CSA (AHI ≥ 15 events/h), and those with no to mild sleep apnea (AHI < 15 events/h [control]).

RESULTS

The prevalence of ESVEA was higher in patients with OSA (n = 430) and CSA (n = 150) compared with control participants (n = 76): 0%, 9%, and 12%, respectively. The prevalence of AF in the control, OSA, and CSA groups was 9%, 17%, and 27%; the prevalence of > 10 PVC/h was 45%, 59%, and 63%. In multivariable regression analyses, premature atrial complexes/h was associated with OSA severity (obstructive AHI: 22.4% increase per 10 events/h [95% CI, 5.2-42.3; P = .009), although neither obstructive nor central AHI was associated with AF or > 10 PVC/h.

INTERPRETATION

In patients with HFrEF, the prevalences of nocturnal ESVEA, AF, and PVC > 10/h were higher in those with OSA or CSA than in those without OSA or CSA, and OSA severity was related to the burden of nocturnal atrial ectopy. Severity of OSA or CSA was not significantly related to AF or > 10 PVC/h.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT01128816; URL: www.

CLINICALTRIALS

gov.

A systematic review on the association of sleep-disordered breathing with cardiovascular pathology in adults

Sleep-disordered breathing (SDB) is characterized by repeated breathing pauses during sleep. The prevalence of SDB varies widely between studies. Some longitudinal studies have found an association of SDB with incident or recurrent cardiovascular events. We sought to systematically describe the current data on the correlation between SDB and cardiovascular pathology. Studies were included if they were original observational population-based studies in adults with clearly diagnosed SDB. The primary outcomes include all types of cardiovascular pathology. We carried out pooled analyses using a random effects model. Our systematic review was performed according to the PRISMA and MOOSE guidelines for systematic reviews and was registered with PROSPERO. In total, 2652 articles were detected in the databases, of which 76 articles were chosen for full-text review. Fourteen studies were focused on samples of an unselected population, and 8 studies were focused on a group of persons at risk for SDB. In 5 studies, the incidence of cardiovascular pathology in the population with SDB was examined. In total, 49 studies described SDB in patients with cardiovascular pathology. We found an association between SDB and prevalent /incident cardiovascular disease (pooled OR 1.76; 95% CI 1.38–2.26), and pooled HR (95% CI 1.78; 95% CI 1.34–2.45). Notably, in patients with existing SDB, the risk of new adverse cardiovascular events was high. However, the relationship between cardiovascular disease and SDB is likely to be bidirectional. Thus, more large-scale studies are needed to better understand this association and to decide whether screening for possible SDB in cardiovascular patients is reasonable and clinically significant.

Ventrikuläre Arrhythmien bei obstruktiver und zentraler Schlafapnoe

Hintergrund

Ventrikuläre Arrhythmien treten mit einer hohen Prävalenz auf und sind mit einer hohen Morbidität und Mortalität assoziiert. Sowohl die obstruktive (OSA) als auch die zentrale (ZSA) Schlafapnoe können auf Grund ihrer Pathophysiologie zu vermehrten ventrikulären Arrhythmien beitragen.

Ziel

Dieser Artikel soll die komplexen Zusammenhänge und Erkenntnisse jüngster Forschungen bezüglich schlafbezogenen Atmungsstörungen (SBAS) und ventrikulärer Arrhythmien und deren Therapiemöglichkeiten beleuchten.

Material und Methoden

Es erfolgte eine Literaturrecherche basierend auf prospektiven, retrospektiven, klinischen und experimentellen Studien sowie Reviews, Metaanalysen und aktuellen Leitlinien, die seit 2014 in der Medline-Datenbank gelistet wurden.

Ergebnisse

Es besteht ein bidirektionaler Zusammenhang zwischen der SBAS und ventrikulären Arrhythmien. Intermittierende Hypoxie, oxidativer Stress, wiederkehrende Arousals, intrathorakale Druckschwankungen und kardiales Remodeling tragen im Rahmen der SBAS zu einer erhöhten ventrikulären Arrhythmieneigung bei. Der Schweregrad der OSA, gemessen mittels Apnoe-Hypopnoe-Index, ist mit der Prävalenz ventrikulärer Arrhythmien assoziiert. Ähnliche Ergebnisse liegen für Patienten mit ZSA und Herzinsuffizienz vor. Studien zu ventrikulären Arrhythmien bei ZSA-Patienten ohne Herzinsuffizienz fehlen. Eine Positivdrucktherapie (PAP) bei OSA- oder ZSA-Patienten führte in verschiedenen Studien zu einer reduzierten Anzahl an ventrikulären Arrhythmien. Dieser Zusammenhang konnte jedoch nicht in allen Studien bestätigt werden. Ventrikuläre Arrhythmien treten bei der OSA gehäuft nachts auf, bei der ZSA gleichmäßig über den Tag verteilt.

Diskussion

Bisherige Studien weisen einen Zusammenhang zwischen der OSA bzw. der ZSA und ventrikulären Arrhythmien trotz unterschiedlicher Pathophysiologie nach. Hinsichtlich des Effektes der PAP auf ventrikuläre Arrhythmien bei Patienten mit OSA und ZSA sind weitere Studien erforderlich.

Atrial fibrillation is associated with central sleep apnea in clinic patients undergoing diagnostic polysomnography

Introduction

Sleep apnea is highly prevalent in patients with atrial fibrillation (AF). Obstructive sleep apnea (OSA) is the most common type, and best studied in the context of AF. However, recent investigations have indicated that central sleep apnea (CSA) may be a risk factor for incident AF. We evaluated the burden of CSA events in patients referred for diagnostic polysomnography (PSG) and whether AF is associated with CSA.

Methods

We identified patients with and without a history of AF who underwent clinically indicated PSG in a matched manner. OSA was defined as obstructive apnea‐hypopnea index (AHI) ≥15/h, and CSA was defined as central apnea index (CAI) ≥5/h. The association between AF and CSA was evaluated using multivariable logistic regression.

Results

Among 465 patients included, mean AHI was 25.5/h, and mean CAI was 1.7/h. OSA prevalence was 53.3%, while CSA prevalence was 8.4%. The prevalence of OSA in the AF and non‐AF groups (54.7% vs 52.0%, P = .56) was similar. CSA was more common in the AF group (12.3% vs 4.4%, P = .002). In multivariable analysis, AF (OR: 2.19 [1.02, 5.03], P = .05), male gender (OR: 2.5 [1.17, 5.84], P = .02), and older age (OR: 2.44, [1.16, 5.46], P = .02) were associated with CSA.

Conclusion

Though CSA is much less common than OSA in patients with AF, the presence of AF is independently associated with CSA.

The prevalence of sleep-disordered breathing in Northwest Russia: The ARKHsleep study

Sleep-disordered breathing (SDB) is a chronic condition characterized by repeated breathing pauses during sleep. The reported prevalence of SDB in the general population has increased over time. Furthermore, in the literature, a distinction is made between SDB, obstructive sleep apnea (OSA), and "OSA syndrome" (OSAS). Patients with SDB are at increased risk of comorbid cardiovascular diseases (CVDs). The aim of the ARKHsleep study was to assess the prevalence of SDB in general and of OSA and OSAS in particular. A total of 1050 participants aged 30-70 years, who were randomly selected from a population register, were evaluated for the probability of SDB using the Epworth Sleepiness Scale score and body mass index. Sleep was recorded for one night via home sleep apnea testing (Somnolter®). Medical conditions were determined from medical records. Additional data included background characteristics, anthropometric variables, blood pressure, and scores from four questionnaires. The survey sample consisted of 41.2% males and had a mean age of 53.1 ± 11.3 years. The prevalence of mild-to-severe, moderate-to-severe, and severe SDB was 48.9% [45.8-51.9], 18.1% [15.9-20.6], and 4.5% [3.2-5.8], respectively. Individuals reporting snoring or breathing pauses had a higher severity of SDB than individuals free of symptoms. The ARKHsleep study revealed a high burden of both SDB and CVD; however, more large-scale cohort studies and intervention studies are needed to better understand whether the early recognition and treatment of mild SDB with or without symptoms will improve cardiovascular prognosis and/or quality of life.

Plasma fatty acid-binding protein 4 (FABP4) level is associated with abnormal QTc interval in patients with stable angina and chronic kidney disease

BACKGROUND

Fatty acid-binding protein 4 (FABP4) (also known as adipocyte FABP or adipocyte P2) is expressed in adipocytes, macrophages, and capillary endothelial cells. Previous studies have shown associations among plasma FABP4, insulin resistance, metabolic syndrome, diabetes mellitus, greater coronary plaque burden, coronary artery disease, heart failure, and mortality. However, little is known about the relationship between FABP4 level and prolonged QT interval. The aim of this study was to investigate whether plasma FABP4 level is associated with a prolonged QT interval by analyzing 12-lead electrocardiograms (ECGs) in patients with stable angina and chronic kidney disease (CKD).

METHODS

This study included 397 consecutive patients with stable angina and CKD who were enrolled in a disease management program. Plasma FABP4 concentrations were measured using enzyme-linked immunosorbent assays. A 12-lead ECG recording was obtained from each patient. We assessed the relationships between FABP4 levels (both as a continuous variable and stratified by tertile) at admission and corrected QT (QTc) prolongation.

RESULTS

Patients with an abnormal QTc interval had higher median plasma FABP4 levels than those with borderline and normal QTc intervals (15.9 ng/mL vs. 10.2 ng/mL vs. 8.5 ng/mL, respectively, P < 0.0001). Statistically significant associations were observed between plasma FABP4 levels and QTc interval (β = 0.267, P < 0.0001). Using multivariate and trend analyses, a higher concentration of plasma FABP4 level was independently associated with QTc prolongation in patients with stable angina and CKD.

CONCLUSION

In this study, plasma FABP4 levels were significantly higher in the patients with an abnormal QTc interval and were correlated with QTc prolongation. Further studies are required to elucidate whether plasma FABP4 plays a role in the pathogenesis of QTc prolongation.

Prevalence and clinical characteristics of obstructive- and central-dominant sleep apnea in candidates of catheter ablation for atrial fibrillation in Japan

INTRODUCTION

We aimed to study the prevalence and types of sleep apnea (SA) as well as their clinical characteristics in atrial fibrillation (AF) ablation candidates in Japan.

METHODS

Before catheter ablation, 197 consecutive AF patients (age: 60 ± 9 years, body mass index; 25.0 ± 3.0) were evaluated with portable polygraphy. We compared the clinical characteristics, according to the severity of SA as well as its types, as defined by the presence of obstruction and the mixed vs. central apnea indices.

RESULTS

The mean apnea-hypopnea index (AHI) was 17.7 ± 11.9, with 135 AF patients having an AHI ≥10 (68.5%). Patients with an AHI ≥10 had a significantly higher body mass index, plasma brain natriuretic peptide (BNP) level, prevalence of hypertension, and larger left atrial size. Among patients with an AHI ≥10, the incidence of obstructive-dominant SA was 60.9% and that of central-dominant SA was 7.6%. The prevalence of hypertension was significantly higher in obstructive-dominant SA patients (obstructive vs. central: 48.3% vs. 20.0%, P = 0.038). The obstructive apnea index correlated with plasma BNP level and age, but the central and mixed apnea indices did not.

CONCLUSIONS

The prevalence of SA was common in AF ablation candidates, even without an obesity epidemic, and the SA type was predominantly obstructive. Portable polygraphy was useful for detecting undiagnosed SA patients in AF ablation candidates.

Serum albumin level and abnormal corrected QT interval in patients with coronary artery disease and chronic kidney disease

BACKGROUND

Lower concentrations of serum albumin appear to be associated with an increased risk of all-cause and cardiovascular mortality, coronary heart disease, heart failure and stroke. However, little is known about the relationship between serum albumin level and prolonged QT interval.

AIM

To investigate whether lower serum albumin is associated with prolonged QT interval by recording 12-lead electrocardiography in patients with coronary artery disease and chronic kidney disease.

METHODS

This study included 1383 consecutive patients with coronary artery disease and chronic kidney disease (841 with acute coronary syndrome and 542 with elective percutaneous coronary intervention patients) who were enrolled in a disease management programme. Twelve-lead electrocardiography was recorded in each subject. We assessed the relationship between albumin levels (both as a continuous variable and stratified by tertile) at admission and corrected QT (QTc) prolongation.

RESULTS

Patients with abnormal QTc interval had lower serum albumin levels than those with normal and borderline QTc intervals. Statistically significant negative associations were observed between serum albumin levels and QTc interval (β = -0.211, P < 0.0001). Using multivariate and trend analyses, a lower concentration of serum albumin was independently associated with QTc prolongation in both the patients with acute coronary syndrome and elective percutaneous coronary intervention patients.

CONCLUSION

Concentrations of serum albumin were significantly lower in the patients with an abnormal QTc interval and were associated with QTc prolongation. Further studies are needed to clarify whether lower serum albumin plays a role in the pathogenesis of QTc prolongation.

Prognostic Importance of Novel Oxygen Desaturation Metrics in Patients With Heart Failure and Central Sleep Apnea

BACKGROUND

Sleep-disordered breathing, particularly central sleep apnea (CSA), is highly prevalent in heart failure (HF) and an independent prognostic marker. We assessed the hypothesis that an increased hypoxemic burden during sleep may have greater prognostic value than the frequency of apneic and hypopneic episodes.

METHODS AND RESULTS

We prospectively conducted overnight cardiorespiratory polygraphy on consecutive HF patients referred to our hospital from 2008 to 2011. We studied CSA defined by an apnea-hypopnea index (AHI) of ≥5 events/h with >75% of all events being central in origin. We determined the AHI, proportion of the sleep time with SpO₂ <90% (T90%), and proportion of the recording time that 4% desaturation events occurred (4%POD). We studied 112 HF patients with either systolic or diastolic dysfunction. During a follow-up period of 37 ± 25 months, 32 patients (29%) died. Nonsurvivors had a higher 4%POD compared with survivors (11 ± 6.4% vs 19 ± 13%; P = .001), but did not differ significantly from survivors regarding AHI and T90%. An adjusted logistic regression analysis revealed that the 4%POD was the best independent predictor of mortality.

CONCLUSIONS

The 4%POD, a novel metric for the nocturnal hypoxemic burden, is an independent prognostic marker in HF patients affected by CSA.

Effects of Nasal Septum Deviation and Septoplasty on Cardiac Arrhythmia Risk

OBJECTIVE

Upper airway obstruction (UAO) can result in cardiac complications, including arrhythmias and sudden cardiac death. Nasal septum deviation (NSD) is a common cause of UAO. The aim of this study was to assess the risk of cardiac arrhythmias in patients with NSD. To assess this risk, we measured noninvasive indicators of atrial arrhythmia (P-wave dispersion [Pd]) and ventricular arrhythmia (corrected QT dispersion [QTcd]) and compared these values between NSD patients and healthy subjects.

STUDY DESIGN

Prospective study.

SETTINGS

Tertiary referral center.

SUBJECTS AND METHODS

This study included 53 consecutive patients who had underwent septoplasty due to marked NSD. Electrocardiographic records were used to determine Pd and QTcd values preoperatively and 6 months postoperatively. Fifty-three consecutive age- and sex-matched subjects without any UAO were also examined as a control group.

RESULTS

Preoperative Pd and QTcd values were significantly higher in NSD patients than in the control group (Pd: 57.40 ± 14.21 vs 34.11 ± 7.12 milliseconds, P < .001; QTcd: 81.77 ± 16.39 vs 50.25 ± 11.51 milliseconds, P < .001, respectively). In addition, Pd and QTcd values were significantly greater in preoperative NSD patients when compared with the same patients postoperatively (Pd: 57.40 ± 14.21 vs 36.32 ± 8.9 milliseconds, P = .013; QTcd: 81.77 ± 16.39 vs 55.76 ± 11.4 milliseconds, P = .012, respectively).

CONCLUSION

In conclusion, NSD patients are at risk for both atrial and ventricular cardiac arrhythmias; however, septoplasty in these patients can relieve UAO and reduce the risk of arrhythmias.

Sleep, death, and the heart

Obstructive and central sleep apnea have been associated with increased risk of adverse cardiovascular events and mortality. Sympathetic dysregulation occurring as a result of the respiratory disturbance is thought to play a role in this increased risk. Sleep apnea increases the risk of arrhythmias, myocardial ischemia/infarction, stroke, and heart failure, all of which may increase mortality risk. A higher incidence of nocturnal arrhythmias, cardiac ischemia, and sudden death has been noted in subjects with sleep-disordered breathing (SDB). In this review, the association between SDB and each of these conditions is discussed, as well as the potential mechanisms underlying these risks and the effects of treatment of SDB. Particular emphasis is placed on the relationship between SDB and nocturnal atrial and ventricular arrhythmias, myocardial ischemia/infarction and sudden death.

Obstructive Sleep Apnea and Atrial Fibrillation: Pathophysiology and Implications for Treatment

Obstructive sleep apnea (OSA) is increasingly recognized as an important risk factor for arrhythmogenesis. Epidemiological and clinical studies have suggested a strong association between OSA and atrial fibrillation (AF). With the increasing global epidemic of obesity, the incidence of OSA is also expected to rise. Various mechanisms mediated through adverse electrical and structural changes have been proposed to explain the increased risk of AF in patients with OSA. Multiple studies have also observed a greater risk of AF recurrence after cardioversion and catheter ablation (CA) in the patients with untreated OSA. The epidemiological and pathophysiological associations between OSA and AF have significant implications on the treatment outcomes of rhythm-control strategies for AF. Adequate screening and optimal management of OSA are of key importance to help improve the clinical outcomes following cardioversion and CA. In this review, we sought to describe the role of various mechanisms by which OSA mediates the pathogenesis of AF and contributes to adverse outcomes following CA.

Mechanisms and clinical consequences of untreated central sleep apnea in heart failure

Central sleep apnea (CSA) is a highly prevalent, though often unrecognized, comorbidity in patients with heart failure (HF). Data from HF population studies suggest that it may present in 30% to 50% of HF patients. CSA is recognized as an important contributor to the progression of HF and to HF-related morbidity and mortality. Over the past 2 decades, an expanding body of research has begun to shed light on the pathophysiologic mechanisms of CSA. Armed with this growing knowledge base, the sleep, respiratory, and cardiovascular research communities have been working to identify ways to treat CSA in HF with the ultimate goal of improving patient quality of life and clinical outcomes. In this paper, we examine the current state of knowledge about the mechanisms of CSA in HF and review emerging therapies for this disorder.

Death and disability in patients with sleep apnea--a meta-analysis

BACKGROUND

Several studies have been attempting to ascertain the risks of Sleep Apnea Syndrome (SAS) and its morbidity and mortality.

OBJECTIVE

The main objective was to verify whether SAS increases the risk of death; the secondary objective was to evaluate its morbidity in relation to cardiovascular disease and the number of days hospitalized.

METHODS

A systematic review and a meta-analysis were performed of the published literature. The research focused on studies comparing the number of deaths in patients with untreated SAS and in patients with non-SAS.

RESULTS

The meta-analysis was based on 13 articles, corresponding to a total of 13394 participants divided into two groups (non-SAS = 6631; SAS = 6763). The meta-analysis revealed a clear association of SAS with the occurrence of fatal events, where the presence of SAS corresponded to a 61% higher risk of total mortality (OR=1.61; CI: 1.43 - 1.81; p < 0.00001), while the risk of death from cardiac causes was 2.52 times higher in these patients (OR = 2.52; IC: 1.80 - 3.52; p < 0.00001). Similar results were obtained for mortality from other causes (OR = 1.68; CI: 1.08 - 2.61; p = 0.02). Resembling results were obtained in the remaining outcomes: non-fatal cardiovascular events were higher in the SAS group (OR = 2.46; IC: 1.80 - 3.36; p < 0.00001), the average number of days hospitalized was also higher in the SAS group (IV = 18.09; IC: 13.34 - 22.84; p < 0.00001).

CONCLUSION

The results show that untreated SAS significantly increases the risk of death, cardiovascular events and the average number of days hospitalized.

Arrhythmia risk associated with sleep disordered breathing in chronic heart failure

The intersecting relationships of sleep disordered breathing (SDB), arrhythmogenic risk and chronic heart failure (HF) are complex and most likely multi-directional and synergistic. Autonomic dysfunction is a common pathophysiological feature of each of these entities. Intermittent hypoxia, hypercapnia, mechanical cardiac influences due to upper airway obstruction and rostral fluid shifts are SDB-specific mechanisms which may trigger, perpetuate and exacerbate HF and arrhythmogenesis. Specific pathophysiological mechanisms will vary according to the predominance of central as compared to obstructive sleep apnea. The risk of cardiac arrhythmias and HF attributable to SDB may be considerable given the high prevalence of SDB and its likely physiologic burden. The current review focuses on the data, which have accrued elucidating the specific contributory mechanisms of SDB in cardiac arrhythmias and HF, highlighting the clinical relevance and effects of standard SDB treatment on these outcomes, and describing the role of novel therapeutics.

Sleep-disordered breathing increases the risk of arrhythmias

Sleep-disordered breathing (SDB) has been consistently associated with increased risk for cardiovascular diseases, including arrhythmias. The purpose of this review is to elucidate the several pathophysiologic pathways such as repetitive hypoxia and reoxygenation, increased oxidative stress, inflammation and sympathetic activation that may underlie the increased incidence of arrhythmias in SDB patients. We discuss in particular the incidence of ventricular arrhythmias, atrial fibrillation and bradyarrhythmias in SDB patients. In addition, we discuss the electrocardiographic alteration such as ST-T changes during apneic events and QT dispersion induced by SDB that may trigger complex ventricular arrhythmias and sudden cardiac death. Finally, we consider also the therapeutic interventions such as continuous positive airways pressure therapy, a standard treatment for SDB, that may reduce the incidence and recurrence of supraventricular and ventricular arrhythmias in patients with SDB.