Cardioversion of atrial fibrillation or atrial flutter into sinus rhythm reduces nocturnal central respiratory events and unmasks obstructive sleep apnoea

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.

Sleep apnea in patients undergoing coronary artery bypass grafting: Impact on perioperative outcomes

Sleep-disordered breathing is common in patients with coronary artery disease undergoing coronary artery bypass grafting. Sleep-disordered breathing is associated with increased perioperative morbidity, arrhythmias (e.g. atrial fibrillation) and mortality. This study investigated the impact of sleep-disordered breathing on the postoperative course after coronary artery bypass grafting, including development of atrial fibrillation. This prospective single-centre cohort study included adults undergoing coronary artery bypass grafting. All were screened for sleep-disordered breathing (polygraphy) and atrial fibrillation (electrocardiogram) preoperatively; those with known sleep-disordered breathing or atrial fibrillation were excluded. Endpoints included new-onset atrial fibrillation, duration of mechanical ventilation, time in the intensive care unit, and postoperative infection. Regression analysis was performed to identify associations between sleep-disordered breathing and these outcomes. A total of 508 participants were included (80% male, median age 68 years). The prevalence of any (apnea-hypopnea index ≥ 5 per hr), moderate (apnea-hypopnea index = 15-30 per hr) and severe (apnea-hypopnea index > 30 per hr) sleep-disordered breathing was 52.9%, 9.3% and 10.2%, respectively. All-cause 30-day mortality was 0.98%. After adjustment for age and sex, severe sleep-disordered breathing was associated with longer respiratory ventilation support (crude odds ratio [95% confidence interval] 5.28 [2.18-12.77]; p < 0.001) and higher postoperative infection rates (crude odds ratio 3.32 [1.45-7.58]; p < 0.005), but not new-onset atrial fibrillation or mortality. New-onset atrial fibrillation was significantly associated with postoperative infection and prolonged hospital stay. The significant associations between sleep-disordered breathing and several adverse outcomes after coronary artery bypass grafting support the need for preoperative sleep-disordered breathing screening in individuals undergoing cardiac surgery.

Impact of sleep apnoea on 30 day hospital readmission rate and cost in heart failure with reduced ejection fraction

AIMS

In this study, we estimated the 30 day all-cause and heart failure-specific readmission rates, predictors, mortality, and hospitalization costs in patients with obstructive sleep apnoea admitted with acute decompensated heart failure with reduced ejection fraction.

METHODS AND RESULTS

This is a retrospective cohort study using the Agency of Healthcare Research and Quality's National Readmission Database for the year 2019. The primary outcome was the 30 day all-cause hospital readmission rate. The secondary outcomes were (i) in-hospital mortality rate for index admissions; (ii) 30 day mortality rate for index hospitalizations; (iii) the five most common principal diagnosis for readmission; (iv) readmission in-hospital mortality rate; (v) length of hospital stay; (vi) independent risk factors for readmission; and (vii) hospitalization costs. We identified 6908 hospitalizations that met our study definition. The mean patient age was 62.8 years, and women comprised only 27.6% of patients. The 30 day all-cause readmission rate was 23.4%. 48.9% of readmissions were due to decompensated heart failure. The in-hospital mortality rate during readmissions was significantly higher than that of the index admission (5.6% vs. 2.4%; P < 0.05). The mean length of stay for patients during index admissions was 6.5 days (6.06-7.02), while during readmissions, it was 8.5 days (7.4-9.6; P < 0.05). The mean total hospitalization charges at index admissions were $78 438 (68 053-88 824), while during readmissions, they were higher at $124 282 (90 906-157 659; P < 0.05). The mean total cost of hospitalization during index admissions was $20 535 (18 311-22 758), while at readmissions, it was higher at $29 954 (24 041-35 867; P < 0.05). The total hospital charges for all 30 day readmissions were $195 million, and total hospital costs was $46.9 million. The variables found to be associated with increased rate of readmissions were patients with Medicaid insurance, higher Charlson co-morbidity Index, and longer length of stay. The variables associated with lower rate of readmissions were prior percutaneous coronary intervention and patients with private insurance.

CONCLUSIONS

In patients with obstructive sleep apnoea admitted with heart failure with reduced ejection fraction, we found a substantial all-cause readmission rate of 23.4% with heart failure readmission constituting about 48.9% of readmissions. Readmissions were associated with higher mortality and resource use.

Effects of sacubitril-valsartan on central and obstructive apneas in heart failure patients with reduced ejection fraction

OBJECTIVE

This study aimed to evaluate the effect of sacubitril-valsartan (SV) on central apneas (CA) and obstructive apneas (OA) in patients with heart failure with reduced ejection fraction (HFrEF).

METHODS

In patients with HFrEF, SV initiation was titrated to the highest tolerable dosage. Patients were evaluated with portable apnea monitoring, echocardiography, and cardiopulmonary exercise testing at baseline and 3 months later.

RESULTS

Of a total of 18 patients, 9 (50%) had OA, 7 (39%) had CA, and 2 (11%) had normal breathing. SV therapy was related to a reduction in NT-pro BNP and an improvement in LV function after 3 months. Portable apnea monitoring revealed a significant decrease of the respiratory event index (REI) after treatment with SV (20 ± 23 events/h to 7 ± 7 events/h, p = 0.003). When subgrouping according to type of apneas, REI, and time spent below 90% saturation (T90) decreased in patients with CA and OA (all p < 0.05).

CONCLUSION

In this prospective study, SV treatment for 3 months in patients with CA and OA is associated with a significant decrease in REI.

Angiologie und schlafbezogene Atmungsstörungen: Neues im DGK-Positionspapier?

Schlafbezogene Atmungsstörungen (SBAS) stellen ein gesundheitliches Risiko dar; sie beeinflussen Lebensqualität und Prognose negativ. Besonders gefährdet sind dabei angiologische Patienten mit kardiovaskulären Begleiterkrankungen wie arterielle Hypertonie, Herzinsuffizienz oder Vorhofflimmern. Dies zum einen, da die Diagnostik wegen einer Überlagerung der Symptome häufig erschwert ist, zum anderen aber auch durch eine unmittelbare Korrelation der Pathophysiologie beider Erkrankungen, die gegenseitig ihren Progress begünstigen. Die sorgfältige Fahndung und Therapie einer SBAS ist somit bei diesen Patienten besonders herausfordernd. Es stehen mit nicht invasiven Beatmungsformen und implantierbaren Devices sowie der wachsenden telemedizinischen Infrastruktur zunehmend Optionen zur Verfügung, welche die Symptomlast und die gesundheitlichen Risiken reduzieren können. Deshalb fasst der folgende Artikel neue Entwicklungen zu SBAS zusammen und gibt einen Überblick über aktuelle Empfehlungen.

Obstructive sleep apnea and atrial fibrillation: insights from a bidirectional Mendelian randomization study

Background

Observational studies have suggested that obstructive sleep apnea (OSA) is in relation to atrial fibrillation (AF); however, these studies might be confounded and whether the relationship is causal remains unclear. We conducted a bidirectional Mendelian randomization (MR) study to clarify the causal inference between OSA and AF.

Methods

Genetic instruments for OSA and AF were obtained from genome-wide association studies. The fixed-effects inverse-variance weighted (IVW) method was used as the main method, supplemented by several sensitivity analyses. For replication, another AF dataset was used to validate the causal effect of OSA on AF. Furthermore, multivariable MR analyses were performed to obtain direct estimates adjusting for potential confounders.

Results

Genetic liability to OSA was found to be significantly associated with a higher AF risk in the fixed-effects IVW method [odds ratio (OR) 1.210; 95% CI 1.119–1.307; P = 1.51 × 10^–6]. The results were consistent in MR sensitivity analyses as well as in replication analyses, and the significance remained after adjusting for potential confounders. In the reverse MR analyses, there was no causal effect of AF on OSA.

Conclusions

Our study strengthened the causal evidence of genetically predicted OSA with a higher AF risk. Early screening and appropriate management of OSA might show anti-arrhythmic benefits.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01180-5.

Sleep apnea and atrial fibrillation: challenges in clinical and translational research

INTRODUCTION

Sleep-disordered breathing (SDB) is present in 21-74% of all patients with atrial fibrillation (AF). Treatment of SDB by positive airway pressure may help to prevent recurrence of AF after electrical cardioversion and help to improve AF ablation success rates in non-randomized studies.

AREAS COVERED

In this review, the current understanding of the atrial arrhythmogenic pathophysiology of SDB is summarized, and diagnostic and therapeutic challenges in AF patients are discussed. Current international recommendations are presented, and a comprehensive literature search is undertaken.

EXPERT OPINION

AF patients with SDB rarely report SDB-related symptoms such as daytime sleepiness. Therefore, systematic home sleep testing evaluation should be considered for all patients eligible for rhythm control strategy. A close interdisciplinary collaboration between the electrophysiologist/cardiologist, nurses and sleep-specialists are required for the management of SDB in AF patients. An arrhythmia-orientated assessment of SDB may better quantify SDB-related AF risk in an individual patient and may help to better guide targeted and personalized SDB treatment in AF patients as a component of rhythm and symptom control strategies. Finally, randomized controlled trials are needed to confirm the relationship between SDB and AF, and the benefits of routine testing and treatment of SDB in AF patients.

Prevalence and Assessment of Sleep-Disordered Breathing in Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis

BACKGROUND

In this study, we sought to estimate the prevalence of concomitant sleep-disordered breathing (SDB) in patients with atrial fibrillation (AF) and to systematically evaluate how SDB is assessed in this population.

METHODS

We searched Medline, Embase and Cinahl databases through August 2020 for studies reporting on SDB in a minimum 100 patients with AF. For quantitative analysis, studies were required to have systematically assessed for SDB in consecutive AF patients. Pooled prevalence estimates were calculated with the use of the random effects model. Weighted mean differences and odds ratios were calculated when possible to assess the strength of association between baseline characteristics and SDB.

RESULTS

The search yielded 2758 records, of which 33 studies (n = 23,894 patients) met the inclusion criteria for qualitative synthesis and 13 studies (n = 2660 patients) met the meta-analysis criteria. The pooled SDB prevalence based on an SDB diagnosis cutoff of apnea-hypopnea index (AHI) ≥ 5/h was 78% (95% confidence interval [CI] 70%-86%; P < 0.001). For moderate-to-severe SDB (AHI ≥ 15/h), the pooled SDB prevalence was 40% (95% CI 32%-48%; P < 0.001). High degrees of heterogeneity were observed (I² = 96% and 94%, respectively; P < 0.001). Sleep testing with the use of poly(somno)graphy or oximetry was the most common assessment tool used (in 22 studies, 66%) but inconsistent diagnostic thresholds were used.

CONCLUSIONS

SDB is highly prevalent in patients with AF. Wide variation exists in the diagnostic tools and thresholds used to detect concomitant SDB in AF. Prospective systematic testing for SDB in unselected cohorts of AF patients may be required to define the true prevalence of SDB in this population.

A case of Cheyne-Stokes breathing emerging in a patient with atrial fibrillation and an implanted hypoglossal nerve stimulator

NONE

Treatment emergent central sleep apnea (TECSA) can occur with positive airway pressure (PAP) therapy, mandibular advancement devices, and now recent cases with hypoglossal nerve stimulator (HNS) therapy during treatment for obstructive sleep apnea (OSA). There have been few published reports of Cheyne-Stokes breathing (CSB) emerging after implantation of a hypoglossal nerve stimulator (HNS). We present a case of a 76-year-old male with chronic atrial fibrillation and OSA who developed significant CSB after implantation of a HNS device. As popularity increases for alternative treatments of OSA, there should be close monitoring for emergence of CSB, especially in those who may have a propensity for high loop gain abnormalities contributing to central sleep apneas, such as patients with chronic atrial fibrillation. Further research is needed on CSA in patients with HNS implantation and atrial fibrillation, the prevalence of TECSA in the growing HNS therapy population, and the development of future management strategies.

Sacubitril-valsartan treatment is associated with decrease in central apneas in patients with heart failure with reduced ejection fraction

BACKGROUND

To assess the impact of sacubitril-valsartan on apneic burden in patients with heart failure with reduced ejection fraction (HFrEF), 51 stable HFrEF patients planned for switching from an ACE-i/ARB to sacubitril-valsartan were prospectively enrolled.

METHODS AND RESULTS

At baseline and after 6 months of treatment, all patients underwent echocardiography, 24-h cardiorespiratory monitoring, neurohormonal evaluation, and cardiopulmonary exercise testing. At baseline 29% and 65% of patients presented with obstructive and central apneas, respectively. After 6 months, sacubitril-valsartan was associated with a decrease in NT-proBNP, improvement in LV function, functional capacity and ventilatory efficiency. After treatment, the apnea-hypopnea index (AHI) decreased across the 24-h period (p < 0.001), as well as at daytime (p < 0.001) and at nighttime (p = 0.026), proportionally to baseline severity. When subgrouping according to the type of apneas, daytime, nighttime and 24-h AHI decreased in patients with central apneas (all p < 0.01). Conversely, in patients with obstructive apneas, the effect of drug administration was neutral at nighttime, with significant decrease only in daytime events (p = 0.007), mainly driven by reduction in hypopneas.

CONCLUSIONS

Sacubitril-valsartan on top of medical treatment is associated with a reduction in the apneic burden among a real-life cohort of HFrEF patients. The most marked reduction was observed for central apneas.

Impact of Catheter Ablation on Sleep Quality and Relationship Between Sleep Stability and Recurrence of Paroxysmal Atrial Fibrillation After Successful Ablation: 24-Hour Holter-Based Cardiopulmonary Coupling Analysis

Background

Sleep fragmentation and sleep apnea are common in patients with atrial fibrillation (AF). We investigated the impact of radio‐frequency catheter ablation (RFCA) on sleep quality in patients with paroxysmal AF and the effect of a change in sleep quality on recurrence of AF.

Methods and Results

Of 445 patients who underwent RFCA for paroxysmal AF between October 2007 and January 2017, we analyzed 225 patients who had a 24‐hour Holter test within 6 months before RFCA. Sleep quality was assessed by cardiopulmonary coupling analysis using 24‐hour Holter data. We compared cardiopulmonary coupling parameters (high‐frequency coupling, low‐frequency coupling, very‐low‐frequency coupling) before and after RFCA. Six months after RFCA, the high‐frequency coupling (marker of stable sleep) and very‐low‐frequency coupling (rapid eye movement/wake marker) was significantly increased (29.84%–36.15%; P<0.001; and 26.20%–28.76%; P=0.002, respectively) while low‐frequency coupling (unstable sleep marker) was decreased (41.25%–32.13%; P<0.001). We divided patients into 3 tertiles according to sleep quality before RFCA, and the risk of AF recurrence in each group was compared. The second tertile was used as a reference; patients with unstable sleep (Tertile 3) had a significantly lower risk of AF recurrence (hazard ratio [HR], 0.32; 95% CI, 0.12–0.83 for high‐frequency coupling; and HR, 0.22; 95% CI, 0.09–0.58 for low‐frequency coupling).

Conclusions

Sleep quality improved after RFCA in patients with paroxysmal AF. The recurrence rate was significantly lower in patients who had unstable sleep before RFCA. These results suggest that RFCA can influence sleep quality, and sleep quality assessment before RFCA may provide a risk marker for recurrence after RFCA in patients with paroxysmal AF.

Rhythm Control in Heart Failure Patients with Atrial Fibrillation

AF and heart failure (HF) commonly coexist. Left atrial ablation is an effective treatment to maintain sinus rhythm (SR) in patients with AF. Recent evidence suggests that the use of ablation for AF in patients with HF is associated with an improved left ventricular ejection fraction and lower death and HF hospitalisation rates. We performed a systematic search of world literature to analyse the association in more detail and to assess the utility of AF ablation as a non-pharmacological tool in the treatment of patients with concomitant HF.

Interaktionen schlafbezogener Atmungsstörungen mit Vorhofflimmern

Hintergrund

Vorhofflimmern (VHF) ist die häufigste Herzrhythmusstörung. Sowohl die zentrale als auch die obstruktive Schlafapnoe interagieren mit dieser Erkrankung. Intermittierende Hypoxie, oxidativer Stress, wiederkehrende Aufwachreaktionen, intrathorakale Druckveränderungen und atriales Remodeling können im Rahmen einer schlafbezogenen Atmungsstörung (SBAS) zu VHF führen.

Ziel

Dieser Artikel stellt die komplexen Zusammenhänge und Erkenntnisse jüngster Forschungen bezüglich SBAS und VHF sowie die Therapiemöglichkeiten dar.

Material und Methoden

Es erfolgten eine Literaturrecherche von Original- und Übersichtsartikeln sowie Metaanalysen, die zwischen 1963 und 2020 in der PubMed-Datenbank veröffentlicht wurden.

Ergebnisse

Die Erkenntnisse der Studien weisen auf einen bidirektionalen kausalen Zusammenhang zwischen SBAS und VHF hin. Die pathophysiologischen Auswirkungen der obstruktiven und zentralen Schlafapnoe auf VHF sind unterschiedlich. Die Studien, die die Effekte einer Therapie der SBAS auf das Rezidivrisiko von VHF nach Intervention (Kardioversion oder Pulmonalvenenisolation) untersuchen, ergeben bisher kein eindeutiges Bild.

Diskussion

Bisherige Studien bestätigen multiple Interaktionen zwischen SBAS und VHF. Aufgrund widersprüchlicher Ergebnisse hinsichtlich der Effekte einer positiven Atemwegsdrucktherapie auf das Rezidivrisiko von VHF nach Interventionen sind weitere Studien nötig.

Automatic positive airway pressure for obstructive sleep apnea in heart failure with reduced ejection fraction

Background

Moderate-to-severe obstructive sleep apnea (OSA) is highly prevalent in heart failure patients with reduced left ventricular ejection fraction (HFrEF), and is associated with worsening cardiac function and increased mortality.

Objectives

The automatic positive airway pressure (APAP) trial tested the impact of APAP treatment on changes for the pre-specified endpoints: changes in peak oxygen uptake (peak VO₂), percent-predicted peak VO₂ and oxygen uptake at anaerobic threshold (VO₂-AT).

Methods

This randomized, controlled pilot study included patients with chronic, stable HFrEF who had moderate-to-severe OSA. Patients were randomized 1:1 to either APAP (AutoSet™, ResMed) or nasal strips (control) for 6 months.

Results

76 patients have been randomized and 58 had complete data for final analysis. There was a statistically significant change in the APAP intervention arm for the primary endpoint percent-predicted peak VO₂ in comparison to control (67 ± 17 to 73 ± 19%; p = 0.01). Additional primary endpoints peak VO₂ and VO₂-AT showed a trend in increase in the APAP group. Moreover, there were significant improvements within the APAP group for hypoxemia, left ventricular function and quality of life from baseline to 6 months, but not within the control group (p = 0.001 and p = 0.037, respectively).

Conclusion

APAP intervention was shown to significantly improve outcome compared to control group, represented in percent-predicted peak VO₂, an established surrogate marker for cardiovascular prognosis in HFrEF. APAP has additional beneficial effects on hypoxemia, cardiac function and quality of life.

Nightly sleep apnea severity in patients with atrial fibrillation: Potential applications of long-term sleep apnea monitoring

In patients with atrial fibrillation (AF), the prevalence of moderate-to-severe sleep-disordered breathing (SDB) ranges between 21% and 72% and observational studies have demonstrated that SDB reduces the efficacy of rhythm control strategies, while treatment with continuous positive airway pressure lowers the rate of AF recurrence. Currently, the number of apneas and hypopneas per hour (apnea-hypopnea-index, AHI) determined during a single overnight sleep study is clinically used to assess the severity of SDB. However, recent studies suggest that SDB-severity in an individual patient is not stable over time but exhibits a considerable night-to-night variability which cannot be detected by only one overnight sleep assessment. Nightly SDB-severity assessment rather than the single-night diagnosis by one overnight sleep study may better reflect the exposure to SDB-related factors and yield a superior metric to determine SDB-severity in the management of AF. In this review we discuss mechanisms of night-to-night SDB variability, arrhythmogenic consequences of night-to-night SDB variability, strategies for longitudinal assessment of nightly SDB-severity and clinical implications for screening and management of SDB in AF patients.

The effect of atrial fibrillation intervention on nocturnal respiratory events in elderly patients with persistent AF

BACKGROUND

Sleep-disordered breathing (SDB) and atrial fibrillation (AF) are associated. This study investigated the impact of AF intervention on 6-month home sleep testing data.

METHODS

Sixty-seven patients (aged 66 to 86, 53% male) with persistent AF were randomized (1:1:1) to direct current cardioversion (DCCV) (22 patients), permanent pacemaker (PPM) + atrioventricular node ablation (AVNA) + DCCV (22 patients) or AF ablation (23 patients). Baseline and 6-month multichannel home sleep tests with the Watch-PAT200 (Itamar Medical Lts., Caesarea, Israel) were recorded. Implantable cardiac monitors (ICMs) (Medtronic Reveal XT, Minneapolis, Minnesota) in the DCCV and AF ablation groups, and PPM Holters in the 'pace and ablate' group were utilized to assess cardiac rhythm beat-to-beat throughout the study period.

RESULTS

The prevalence of moderate-to-severe SDB [apnoea-hypopnoea index (AHI) ≥ 15/h] was 60%. At 6 months there was no change in AHI, Epworth sleepiness scale, sleep time, % REM sleep, respiratory desaturation index or central apnoeic events. Twenty-five patients (15 AF ablation, 9 DCCV and 1 following DCCV post-AVNA) maintained SR at 6 months confirmed on ICMs in these patients. AHI fell from 29.8 ± 26.6/h to 22.2 ± 20.4/h; P = 0.049.

CONCLUSIONS

SDB is highly prevalent in patients with persistent AF. Restoration of sinus rhythm, and the associated long-term recovery of haemodynamics, is associated with a significant reduction in AHI. This implicates reversal of fluid shift from the lower limbs to the neck region, a key mechanism in the pathogenesis of SDB.

Sleep-disordered breathing in patients with cardiovascular diseases cannot be detected by ESS, STOP-BANG, and Berlin questionnaires

Sleep-disordered breathing (SDB) is highly prevalent in patients with cardiovascular diseases (CVD) and associated with poor outcome. At least 50% of heart failure (HF) patients present with SDB, equally divided in obstructive sleep apnea (OSA) and central sleep apnea (CSA). CVD patients with SDB do not always present with typical SDB symptoms. Therefore, we asked whether established questionnaires allow for the reliable detection of SDB. In this prospective cohort study, 89 CVD patients (54 male, 59 ± 15 years, BMI 30 ± 6 kg/m²) in stable clinical state underwent an ambulatory polygraphy. SDB was defined as an apnea-hypopnea index (AHI) ≥ 15/h. We evaluated the Epworth Sleepiness Scale (ESS), STOP-BANG and Berlin questionnaires as well as anthropometric data and comorbidities regarding their ability to predict SDB. The ESS showed no correlation with SDB. The sensitivity of the Berlin Questionnaire to detect SDB was 73%, specificity was 42%. The STOP-BANG questionnaire showed a sensitivity of 97% while specificity was 13%. Coronary heart disease and/or history of myocardial infarction, hyperuricemia and age significantly contributed to a logistic regression model predicting presence of SDB. However, our regression model explains only 36% of the variance regarding the presence or absence of SDB. The approach to find variables, which would allow an early and reliable differentiation between patients with CVD and coexistence or absence of SDB, failed. Thus, as CVD patients show a high SDB prevalence and poor outcome, only a systematic screening based on measures of respiration-related parameters (i.e., respiratory flow, blood oxygen saturation, etc.) allows for a reliable SDB assessment.

Predominant obstructive or central sleep apnea in patients with atrial fibrillation: influence of characterizing apneas versus apneas and hypopneas

OBJECTIVE/BACKGROUND

Sleep-disordered breathing (SDB) is common in patients with atrial fibrillation (Afib). Although a high proportion of respiratory events are hypopneas, previous studies have only used apneas to differentiate obstructive (OSA) from central (CSA) sleep apnea. This study investigated the impact of using apneas and hypopneas versus apneas only to define the predominant type of SDB in Afib patients with preserved ejection fraction.

PATIENTS/METHODS

This retrospective analysis was based on high-quality cardiorespiratory polygraphy (PG) recordings (07/2007-03/2016) that were re-analyzed using 2012 American Academy of Sleep Medicine criteria, with differentiation of apneas and hypopneas as obstructive or central. Classification of predominant (>50% of events) OSA and CSA was defined based on apneas only (OSA_AI and CSA_AI) or apneas and hypopneas (OSA_AHI and CSA_AHI). SDB was defined as an apnea-hypopnea index ≥5/h.

RESULTS

A total of 211 patients were included (146 male, age 68.7 ± 8.5 y). Hypopneas accounted for >50% of all respiratory events. Based on apneas only, 46% of patients had predominant OSA and 44% had predominant CSA. Based on apneas and hypopneas, the proportion of patients with OSA was higher (56%) and that with CSA was lower (36%). In the subgroup of patients with moderate to severe SDB (AHI ≥ 15/h), the proportion with predominant CSA was 55.2% based on apneas only versus 42.1% with apneas and hypopneas.

CONCLUSIONS

In hospitalized patients with Afib and SDB, use of apneas and hypopneas versus apneas alone had an important influence on the proportion of patients classified as having predominant OSA or CSA.

Sleep, sleep apnea and atrial fibrillation: Questions and answers

Sleep apnea (SA) is a common sleep disorder increasingly recognized as a risk for cardiovascular disease. Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with significant morbidity and mortality. An increasing number of investigations in recent years have linked SA to AF. In this review, we aim to provide a critical overview of the existing evidence in a question and answer format by addressing the following: What is the prevalent association between the two conditions (separating nocturnally detected AF episodes from AF as a prevalent condition)? Is SA a risk factor for incident AF? Is SA a risk factor for recurrence of AF following cardioversion/catheter-based ablation? What is the association between SA and AF in patients with heart failure? Are there signature electrocardiographic markers of AF found in patients with SA? Are there electrophysiology-based studies supporting the link between SA and AF? What other sleep characteristics (beyond SA) are found in patients with AF? What is the impact of SA treatment on AF? What is the effect of AF treatment on sleep? Finally, we address unsolved questions and suggest future directions to enhance our understanding of the AF-SA relationship.

Cardioversion of atrial fibrillation does not affect obstructive sleep apnea

BACKGROUND

Sleep apnea is common in patients with atrial fibrillation, but the effect of the cardioversion of atrial fibrillation to sinus rhythm on central and obstructive apneas is mainly unknown. The primary aim of the study was to analyze the association between cardioversion of atrial fibrillation and sleep apneas, to investigate whether obstructive or central sleep apneas are reduced following cardioversion. A secondary objective was to study the effect on sleep quality.

METHODS

Twenty-three patients with atrial fibrillation were investigated using overnight polysomnography, including esophagus pressure monitoring and ECG, before and after the cardioversion of persistent atrial fibrillation.

RESULTS

Obstructive sleep apnea occurred in 17/23 patients (74%), and central sleep apnea in 6/23 patients (26%). Five patients had both obstructive and central sleep apnea. Sinus rhythm at follow-up was achieved in 16 patients. The obstructive apnea-hypopnea index, central apnea-hypopnea index, and the number of patients with obstructive or central sleep apnea did not differ before and after restoration of sinus rhythm. Sleep time, sleep efficiency, time in different sleep stages, and subjective daytime sleepiness were normal and unaffected by cardioversion.

CONCLUSIONS

Both obstructive and central sleep apneas are highly prevalent in patients with persistent atrial fibrillation. Obstructive sleep apneas are unaffected by the cardioversion of atrial fibrillation to sinus rhythm. The sleep pattern is normal and unaffected by cardioversion in patients with atrial fibrillation.

CLINICAL TRIAL REGISTRATION

Trial number NCT00429884.

Impact of sleep-disordered breathing in patients with acute myocardial infarction: a retrospective analysis

Sleep-disordered breathing (SDB) is associated with an increased risk of cardiovascular events. Previous studies showed that severe SDB has a negative impact on myocardial salvage and progression of left ventricular dysfunction after acute myocardial infarction (AMI). This study investigated the frequency of SDB and the effects of SDB on left ventricular function after AMI. This retrospective study enrolled all patients with AMI who had undergone cardiorespiratory polygraphy for SDB diagnosis. The apnea-hypopnea index was used as a standard metric of SDB severity. SDB was classified as mild (apnea-hypopnea index >5 to <15 per h), moderate (≥15 to <30 per h) or severe (apnea-hypopnea index ≥30 per h). According to the majority of events, SDB was classified as predominant obstructive sleep apnea, central sleep apnea or mixed sleep apnea (mixed SDB). A total of 223 patients with AMI (112 with ST elevation and 111 without ST elevation; 63.2 ± 11.2 years, 82% male, left ventricular ejection fraction 49 ± 12%) were enrolled. SDB was present in 85.6%, and was moderate-to-severe in 63.2%; 40.8% had obstructive sleep apnea, 41.7% had central sleep apnea and 3.1% had mixed SDB. Left ventricular ejection fraction was lower in patients with AMI with severe SDB (45 ± 14%) versus those without SDB (57 ± 7%; P < 0.005). In addition, lower left ventricular ejection fraction (≤45%) was associated with increased frequency (apnea-hypopnea index ≥5 per h in 96%) and severity (apnea-hypopnea index ≥30 per h in 48%) of SDB in general and a higher percentage of central sleep apnea (57%) in particular. SDB is highly frequent in patients with AMI. SDB severity appeared to be linked to impaired left ventricular function, especially in patients with central sleep apnea.

Sleep-Disordered Breathing and Arrhythmia in Heart Failure Patients

Heart failure (HF) treatment remains complex and challenging, with current recommendations aiming at consideration and treatment of comorbidities in patients with HF. Sleep-disordered breathing (SDB) and arrhythmia come into play, as both are associated with quality of life deterioration, and morbidity and mortality increase in patients with HF. Interactions of these diseases are versatile and may appear intransparent in daily practice. Nevertheless, because of their importance for patients' condition and prognosis, SDB and arrhythmia individually, but also through interaction on one another, necessitate attention, following the fact that treatment is requested and desired considering latest research findings and outcomes.

Positive airway pressure therapy in heart failure patients: Long-term effects on lung function

PURPOSE

The prevalence of sleep-disordered breathing (SDB) in patients with heart failure (HF) is high. Positive airway pressure (PAP) is first-choice therapy, but recent data indicates that PAP therapy may increase mortality in HF patients with reduced ejection fraction (HF-REF) and predominant central sleep apnea (CSA). This study investigated long-term effects of PAP therapy on pulmonary function, including respiratory muscle strength. All patients underwent multichannel cardiorespiratory polysomnography (PSG) and comprehensive lung function testing at baseline and follow-up (mean 588±43days).

RESULTS

350 patients (mean age 68±10.7years, 88% male) were included, inspiratory vital capacity, 3.3±0.9 vs 3.2±0.8L; forced expiratory volume in 1s, 2.5±0.7 vs 2.4±0.7L; lung diffusion capacity, 6.2±1.9 vs 5.9±1.8mmol/min/kPa; correction for hemoglobin, 1.1±0.02 vs 1.1±0.3mmol/min/kPa/L; and mouth occlusion pressure, 0.42±0.11 vs 0.4±0.12kPa.

CONCLUSIONS

PAP therapy had no negative nor positive impact on lung function, including respiratory muscle strength, in stable HF-REF patients with SDB, and is therefore safe from a respiratory perspective.

Sleep apnoea and stroke

Sleep disorders have been known to physicians for a long time. In his famous aphorisms, Hippocrates said “Sleep or watchfulness exceeding that which is customary, augurs unfavorably”. Modern medicine has been able to disentangle some of the phenomena that disturb sleep. Among the most notable offenders is sleep apnoea that has gained prominence in the past few decades. It is being proposed as one of the potentially modifiable risk factors for vascular diseases including stroke. The pathological mechanisms linking sleep apnoea to vascular risk factors include hypoxia, cardiac arrhythmias, dysautonomia, impaired glucose tolerance, hypertension, dyslipidaemia and inflammation. In this article, we review literature linking sleep apnoea and stroke, including sleep apnoea as a risk factor for primary prevention with the potential to improve outcome after acute stroke and as a secondary risk factor, amenable to modification and hence vascular risk reduction.

Atrial fibrillation and sleep-disordered breathing

Atrial fibrillation (AF) is a common supraventricular arrhythmia that increases in prevalence with increasing age and in the presence of comorbidities such as heart failure (HF). AF increases the risk of a number of serious complications, including stroke and HF. As a result, the rate of hospitalization is high, making AF a costly disease. Treatment strategies for AF are broadly based around rate and rhythm control, either pharmacological or mechanical. There appear to be a number of links between sleep-disordered breathing (SDB) and AF, although further studies are needed to fully understand the physiological mechanisms that link these conditions. Patients with AF and SDB share a number of risk factors and comorbidities, including age, male sex, hypertension, congestive HF and coronary artery disease (CAD), and the prevalence of SDB in AF is higher than in the general population. Prevalence rates of obstructive sleep apnea (OSA) in patients with AF have been reported to range from 21% to just over 80%. The prevalence of central sleep apnea (CSA) in patients with AF is less well defined, but appears to be particularly high in patients who also have HF and a reduced left ventricular ejection fraction (LVEF). The frequency of apneas can be reduced by effective treatment of AF, while co-existing OSA reduces the effectiveness of treatments for AF and there is an increased risk of arrhythmia recurrence in the presence of SDB. Treating OSA with continuous positive airway pressure (CPAP) therapy has shown the potential to decrease the incidence of AF, improve the effectiveness of AF interventions, and decrease the risk of arrhythmia recurrence, although data from large randomized, controlled clinical trials are lacking. Based on available data, inclusion of SDB recognition and management strategies as part of AF management appears to have the potential to reduce the impact of this arrhythmia at both the individual and societal levels, and has been recognized as important in recent guidelines.