Sleep Disordered Breathing and Heart Failure

Sleep apnea and sudden death in the non-cardiac population: A systematic review

INTRODUCTION

Obstructive sleep apnea (OSA) is one of the main risk factors for cardiovascular diseases and is associated with both morbidity and mortality. OSA has also been linked to arrhythmias and sudden death.

OBJECTIVE

To assess whether OSA increases the risk of sudden death in the non-cardiac population.

METHODS

This is a systematic review of the literature. The descriptors "sudden death" and "sleep apnea" and "tachyarrhythmias" and "sleep apnea" were searched in the PubMed/Medline and SciELO databases.

RESULTS

Thirteen articles that addressed the relationship between OSA and the development of tachyarrhythmias and/or sudden death with prevalence data, electrocardiographic findings, and a relationship with other comorbidities were selected. The airway obstruction observed in OSA triggers several systemic repercussions, e.g., changes in intrathoracic pressure, intermittent hypoxia, activation of the sympathetic nervous system and chemoreceptors, and release of catecholamines. These mechanisms would be implicated in the appearance of arrhythmogenic factors, which could result in sudden death.

CONCLUSION

There was a cause-effect relationship between OSA and cardiac arrhythmias. In view of the pathophysiology of OSA and its arrhythmogenic role, studies have shown a higher risk of sudden death in individuals who previously had heart disease. On the other hand, there is little evidence about the occurrence of sudden death in individuals with OSA and no heart disease, and OSA is not a risk factor for sudden death in this population.

Heart Failure, Investigator-Reported Sleep Apnea and Dapagliflozin: A Patient-Level Pooled Meta-Analysis of DAPA-HF and DELIVER

BACKGROUND

Sleep apnea is more common in patients with heart failure (HF) than in the general population, but little is known about its association with clinical outcomes in various HF phenotypes or how it might modify the effect of HF therapy.

OBJECTIVES

To examine the prevalence of sleep apnea, its association with outcomes and the effects of dapagliflozin in patients with HF with and without sleep apnea in a pooled analysis of 2 trials comparing dapagliflozin to placebo in HFrEF (DAPA-HF trial) and HFmrEF/HFpEF (DELIVER trial).

METHODS

A history of sleep apnea was investigator-reported. The primary outcome was a composite of worsening HF or cardiovascular death.

RESULTS

The prevalence of sleep apnea was 5.7% and 7.8% in patients with HFrEF and HFmrEF/HFpEF, respectively. The primary outcome occurred at a rate of 16.0 in participants with sleep apnea compared to 10.6 per 100 person-years in those without (adjusted HR 1.29 [95%CI, 1.10-1.52]). Compared with placebo, dapagliflozin reduced the risk of the primary endpoint to the same extent in patients with (HR 0.78 [95% CI, 0.59-1.03]) and without sleep apnea (HR 0.79 [0.72-0.87]) [Pinteraction = 0.93]. The beneficial effects of dapagliflozin on other clinical outcomes and symptom burden, physical function, and quality of life were consistent in participants with and without sleep apnea.

CONCLUSIONS

In DAPA-HF and DELIVER, the true prevalence of sleep apnea was likely underestimated. An investigator-reported history of sleep apnea was associated with higher rates of worsening HF events. The benefits of dapagliflozin on clinical outcomes were consistent in patients with and without sleep apnea.

CLINICAL TRIAL REGISTRATION

Unique identifiers: NCT01920711 CONDENSED ABSTRACT: In a pooled analysis of the DAPA-HF and DELIVER trials of more than 11,000 patients with heart failure (HF) across the range of ejection fractions, an investigator-reported history of sleep apnea was associated with higher rates of worsening HF events but not mortality. The beneficial effects of dapagliflozin on clinical outcomes were consistent in patients with and without sleep apnea. These findings provide further evidence for dapagliflozin as a new treatment option for patients with heart failure across the range of ejection fractions.

Preventing new-onset heart failure: Intervening at stage A

Heart failure (HF) prevention is an urgent public health need with national and global implications. Stage A HF patients do not show HF symptoms or structural heart disease but are at risk of HF development. There are no unique recommendations on detecting Stage A patients. Patients in Stage A are heterogeneous; many patients have different combinations of risk factors and, therefore, have markedly different absolute risks for HF. Comprehensive strategies to prevent HF at Stage A include intensive blood pressure lowering, adequate glycemic and lipid management, and heart-healthy behaviors (adopting Life's Essential 8). First and foremost, it is imperative to improve public awareness of HF risk factors and implement healthy lifestyle choices very early. In addition, recognize the HF risk-enhancing factors, which are nontraditional cardiovascular (CV) risk factors that identify individuals at high risk for HF (genetic susceptibility for HF, atrial fibrillation, chronic kidney disease, chronic liver disease, chronic inflammatory disease, sleep-disordered breathing, adverse pregnancy outcomes, radiation therapy, a history of cardiotoxic chemotherapy exposure, and COVID-19). Early use of biomarkers, imaging markers, and echocardiography (noninvasive measures of subclinical systolic and diastolic dysfunction) may enhance risk prediction among individuals without established CV disease and prevent chemotherapy-induced cardiomyopathy. Efforts are needed to address social determinants of HF risk for primordial HF prevention.Central illustrationPolicies developed by organizations such as the American Heart Association, American College of Cardiology, and the American Diabetes Association to reduce CV disease events must go beyond secondary prevention and encompass primordial and primary prevention.

Association of hypoxic burden metrics with cardiovascular outcomes in heart failure and sleep-disordered breathing

AIMS

Heart failure (HF) and sleep-disordered breathing (SDB) frequently coexist. We aimed to compare the prognostic value of different nocturnal hypoxic burden metrics in hospitalized HF patients.

METHODS AND RESULTS

HF patients underwent polygraphy screening for SDB in this prospective cohort. Hypoxic burden metrics assessed using pulse oximetry included time < 90% oxygen saturation (T90), proportion of total recording time < 90% oxygen saturation (TRT90), oxygen desaturation index (ODI), and mean oxygen saturation (meanSO2 ). The prespecified endpoints were the composite of cardiovascular death or admission for worsening HF. This study included 764 hospitalized HF patients, 16.5% and 36.6% of whom had obstructive and central sleep apnoea, respectively. With a median follow-up time of 2.2 years, endpoint events occurred in 410 (53.7%) patients. In univariate and multivariate analyses, T90, TRT90, and meanSO2 were substantially associated with the composite outcome, whereas ODI was not. After multivariate Cox model adjustment, patients with 5.0 ≤ T90 ≤ 52.0 min [hazard ratio (HR) 1.32, 95% confidence interval (CI): 1.02-1.71, P = 0.034] or T90 > 52.0 min (HR 1.56, 95% CI: 1.21-2.02, P = 0.001) had a greater risk of the composite outcome than those with T90 < 5.0 min. The TRT90 and T90 results were similar. Compared with meanSO2  > 95%, meanSO2  < 93% (HR 1.47, 95% CI: 1.16-1.88, P = 0.002) was correlated with adverse outcomes.

CONCLUSIONS

The hypoxic burden metrics T90, TRT90, and meanSO2 , but not ODI, were independent predictors of cardiovascular death or readmission for worsening HF. Indicators of duration and severity, not just the frequency of nocturnal hypoxaemia, should be valued and considered for intervention to improve outcomes in HF patients.

Effects of continuous positive airway pressure therapy on left ventricular performance in patients with severe obstructive sleep apnea

We investigated myocardial performance concerning obstructive sleep apnea (OSA) severity and the benefits of continuous positive airway pressure (CPAP) therapy. In this randomized sham-controlled trial, 52 patients (mean age, 49 years; 92%, males; mean AHI, 59) with severe OSA were randomly assigned to receive either CPAP or sham treatment for 3 months. The severity of OSA was determined using the apnea/hypopnea index (AHI), oxygen desaturation index (ODI), percentage of sleep time below 90% oxygen saturation (T90), and average O₂ saturation during sleep (mean SpO₂). We compared the changes in myocardial work after 3 months of CPAP (n = 26) versus the sham group (n = 26) at rest and during an exercise stress test. Unlike AHI or ODI, indices of hypoxemia including T90 and mean SpO₂ were significantly correlated with global constructive work, as defined by work of left ventricle (LV) that contributes to LV ejection during systole (T90, β = 0.393, p = 0.012; mean SpO₂, β = 0.331, p = 0.048), and global wasted work (GWW), as defined by work of LV that does not contribute to LV ejection (T90, β = 0.363, p = 0.015; mean SpO₂, β =  - 0.370, p = 0.019). After 3 months, GWW decreased (80.0 ± 49.2 to 60.8 ± 26.3, p = 0.009) and global work efficiency increased (94.0 ± 4.5 to 95.7 ± 2.0, p = 0.008) in the CPAP group compared to those in the sham group. At the 3-month follow-up exercise stress echocardiography, worsening of GWW during exercise was significantly decreased in the CPAP group compared to that in the sham group (p = 0.045 at 50 W). Hypoxemia indices were closely associated with myocardial performance in patients with severe OSA. CPAP treatment for 3 months improved left ventricular myocardial performance by decreasing wasted work and increasing work efficacy compared to the sham treatment.

A State-of-the-Art Review on Sleep Apnea Syndrome and Heart Failure

Heart failure (HF) affects many patients worldwide every year. It represents a leading cause of hospitalization and still, today, mortality remains high, albeit the progress in treatment strategies. Several factors contribute to the development and progression of HF. Among these, sleep apnea syndrome represents a common but still underestimated factor because its prevalence is substantially higher in patients with HF than in the general population and is related to a worse prognosis. This review summarizes the current knowledge about sleep apnea syndrome coexisting with HF in terms of morbidity and mortality to provide actual and future perspectives about the diagnosis, evaluation, and treatment of this association.

Prevalence and clinical characteristics of sleep-disordered breathing in patients with heart failure of different left ventricular ejection fractions

PURPOSES

The prevalence of sleep-disordered breathing (SDB) is high in patients with heart failure (HF), while the prevalence of SDB in HF with different left ventricular ejection fractions (LVEF) has rarely been reported. We aimed to explore the prevalence and clinical characteristics of SDB in patients with HF having different LVEF.

METHODS

Patients with stable HF were consecutively enrolled. All patients underwent portable overnight cardiorespiratory polygraphy and echocardiography. According to their LVEF, the patients were divided into the HFrEF (HF with reduced EF, EF < 40%), HFmrEF (HF with mid-range EF, 40 ≤ EF < 50), and HFpEF groups (HF with preserved EF, EF ≥ 50%). The prevalence and clinical data of SDB among the 3 groups were then compared.

RESULTS

A total of 252 patients, including 134 men, were enrolled in the study. The prevalence of SDB in patients with HF was 70%. Obstructive sleep apnea (OSA) was diagnosed in 48% and central sleep apnea (CSA) in 22%. The prevalence of SDB in the HFrEE, HFmrEF, and HFpEF groups was 86%, 86%, and 62%, respectively (P = 0.001). The prevalence of OSA among the 3 groups was 42%, 47%, and 49%, respectively (P = 0.708), while the prevalence of CSA among the 3 groups was 44%, 40%, and 13% (P < 0.001). Logistic regression analysis revealed that age and BMI were independent risk factors for OSA in patients with HF, while LVEF and smoking were independent risk factors for CSA in patients with HF. Correlational analyses revealed that LVEF was negatively correlated with apnea-hypopnea index (AHI) (r = -0.309, P < 0.001) and central apnea index (CAI) ( r = -0.558, P < 0.001), while there was no significant correlation with obstructive apnea index (OAI). The ROC curve revealed that LVEF could predict the occurrence of CSA and SDB, with AUC = 0.683 (95%CI 0.600-0.767, P < 0.001) and AUC = 0.630 (95%CI 0.559-0.702, P = 0.001), but not of OSA.

CONCLUSIONS

SDB was highly common in HF, and the prevalence of SDB was different in HF with different LVEF, mainly due to the difference in cardiac functions. The prevalence and severity of SDB in HFrEF and HFmrEF were significantly higher than those in HFpEF, which was mainly related to the increase in CSA. When HFmrEF was similar to HFrEF in cardiac functions, the prevalence, type, and severity of SDB were similar between the two groups. Changes in LVEF had a significant impact on CAI, but not on OAI. LVEF can predict the occurrence of CSA and SDB to a certain extent.

Practice recommendations for the role of physiotherapy in the management of sleep disorders: the 2022 Brazilian Sleep Association Guidelines

This clinical guideline supported by the Brazilian Sleep Association comprises a brief history of the development of Brazilian sleep physiotherapy, outlines the role of the physiotherapist as part of a sleep health team, and describes the clinical guidelines in respect of the management of some sleep disorders by the physiotherapist (including sleep breathing disorders, i.e., obstructive sleep apnea, central sleep apnea, upper airway resistance syndrome, hypoventilation syndromes and overlap syndrome, and pediatric sleep breathing disorders; sleep bruxism; circadian rhythms disturbances; insomnia; and Willis-Ekbom disease/periodic limb movement disorder. This clinical practice guideline reflects the state of the art at the time of publication and will be reviewed and updated as new information becomes available.

Sleep-disordered breathing in heart failure patients with different etiologies

Background

The prevalence of sleep‐disordered breathing (SDB) is closely related to the severity of heart failure (HF), and the severity of HF is different in patients with HF of different etiologies.

Hypothesis: This study aimed to explore the prevalence of SDB in patients with HFof different etiologies.

Methods

Hospitalized HF patients were consecutively enrolled. All patients underwent portable overnight cardiorespiratory polygraphy. Patients were divided into five groups according to the etiology of HF: ischemic, hypertensive, myocardial, valvular, and arrhythmic. The prevalence of SDB and clinical data was compared among the five groups.

Results

In total, 248 patients were enrolled in this study. The prevalence of SDB in HF was 70.6%, with the prevalence of obstructive sleep apnea (OSA) at 47.6% and central sleep apnea (CSA) at 23.0%. Patients were divided into five groups: ischemic, hypertensive, myocardial, valvular, and arrhythmic. The prevalence of SDB among the five groups was 75.3%, 81.4%, 77.8%, 51.9%, and 58.5% (p = .014), respectively. The prevalence of OSA among the five groups was 42.7%, 72.1%, 36.1%, 37.0%, and 49.1% (p = .009), whereas the CSA was 32.6%, 9.3%, 41.7%, 14.8%, and 9.4% (p < .001), respectively.

Conclusions

SDB is common in HF patients. The prevalence and types of SDB varied in HF with different etiologies, which may be related to the different severities of HF. SDB was highly prevalent in patients with ischemic, hypertensive, and myocardial HF. Hypertensive HF patients were mainly complicated with OSA, while myocardial HF patients were mainly complicated with CSA. Both conditions were highly prevalent in ischemic HF patients. The prevalence of SDB was relatively low in valvular and arrhythmic HF patients, and OSA was the main type.

Effects of Sacubitril-Valsartan on Clinical, Echocardiographic, and Polygraphic Parameters in Patients Affected by Heart Failure With Reduced Ejection Fraction and Sleep Apnea

Background

Heart failure with reduced ejection fraction (HFrEF) is a clinical condition frequently diagnosed in clinical practice. In patients affected by HFrEF, sleep apnea (SA) can be detected among the most frequent comorbidities. Sacubitril–valsartan (sac/val) association has been proven to be effective in reducing disease progression and all-cause mortality in HFrEF patients. Sac/val treatment can potentially attenuate SA development via several pathophysiologic mechanisms, including improvement of global hemodynamics, reduction of extracellular fluid overload, and decrease of sympathetic neural activity.

Methods

We recruited 132 patients affected by HFrEF and SA, already under treatment with continuous positive airway pressure (CPAP), which was discontinued 24 h before the scheduled study timepoints. Physical examination, echocardiography, nocturnal cardio-respiratory monitoring, and laboratory tests were performed in each patient at baseline and after a 6-month treatment with sac/val.

Results

After 6 months, sac/val induced statistically significant changes in clinical, hemodynamic, biohumoral (NT-proBNP, serum electrolytes, creatinine, and uric acid), and echocardiographic parameters. In particular, cardiac index (CI), both atrial and ventricular volumes and global longitudinal strain (GLS) improved. Moreover, polysomnography, carried out during a temporary CPAP interruption, revealed a significant reduction in global apnea-hypopnea index (AHI) value (p < 0.0001), central AHI (p < 0.0001), obstructive AHI (p < 0.0001), oxygen desaturation index (ODI) (p < 0.0001), and percentage time of saturation below 90% (TC90) (p < 0.0001). The changes of CI, estimated glomerular filtration rate (eGFR), NT-proBNP, and tricuspid annular plane excursion (TAPSE) contributed to 23.6, 7.6, 7.3, and 4.8% of AHI variability, respectively, and the whole model accounted for a 43.3% of AHI variation.

Conclusions

Our results suggest that treatment with sac/val is able to significantly improve the cardiorespiratory performance of patients with HFrEF and SA, integrating the positive impact of CPAP. Thus, both CPAP and sac/val therapy may synergistically contribute to lower the risks of both cardiac and pulmonary complications in HFrEF patients with SA.

2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: Developed by the Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). With the special contribution of the Heart Failure Association (HFA) of the ESC

Document Reviewers: Rudolf A. de Boer (CPG Review Coordinator) (Netherlands), P. Christian Schulze (CPG Review Coordinator) (Germany), Magdy Abdelhamid (Egypt), Victor Aboyans (France), Stamatis Adamopoulos (Greece), Stefan D. Anker (Germany), Elena Arbelo (Spain), Riccardo Asteggiano (Italy), Johann Bauersachs (Germany), Antoni Bayes-Genis (Spain), Michael A. Borger (Germany), Werner Budts (Belgium), Maja Cikes (Croatia), Kevin Damman (Netherlands), Victoria Delgado (Netherlands), Paul Dendale (Belgium), Polychronis Dilaveris (Greece), Heinz Drexel (Austria), Justin Ezekowitz (Canada), Volkmar Falk (Germany), Laurent Fauchier (France), Gerasimos Filippatos (Greece), Alan Fraser (United Kingdom), Norbert Frey (Germany), Chris P. Gale (United Kingdom), Finn Gustafsson (Denmark), Julie Harris (United Kingdom), Bernard Iung (France), Stefan Janssens (Belgium), Mariell Jessup (United States of America), Aleksandra Konradi (Russia), Dipak Kotecha (United Kingdom), Ekaterini Lambrinou (Cyprus), Patrizio Lancellotti (Belgium), Ulf Landmesser (Germany), Christophe Leclercq (France), Basil S. Lewis (Israel), Francisco Leyva (United Kingdom), AleVs Linhart (Czech Republic), Maja-Lisa Løchen (Norway), Lars H. Lund (Sweden), Donna Mancini (United States of America), Josep Masip (Spain), Davor Milicic (Croatia), Christian Mueller (Switzerland), Holger Nef (Germany), Jens-Cosedis Nielsen (Denmark), Lis Neubeck (United Kingdom), Michel Noutsias (Germany), Steffen E. Petersen (United Kingdom), Anna Sonia Petronio (Italy), Piotr Ponikowski (Poland), Eva Prescott (Denmark), Amina Rakisheva (Kazakhstan), Dimitrios J. Richter (Greece), Evgeny Schlyakhto (Russia), Petar Seferovic (Serbia), Michele Senni (Italy), Marta Sitges (Spain), Miguel Sousa-Uva (Portugal), Carlo G. Tocchetti (Italy), Rhian M. Touyz (United Kingdom), Carsten Tschoepe (Germany), Johannes Waltenberger (Germany/Switzerland) All experts involved in the development of these guidelines have submitted declarations of interest. These have been compiled in a report and published in a supplementary document simultaneously to the guidelines. The report is also available on the ESC website www.escardio.org/guidelines For the Supplementary Data which include background information and detailed discussion of the data that have provided the basis for the guidelines see European Heart Journal online.

ATS Core Curriculum 2021. Adult Sleep Medicine: Sleep Apnea

The American Thoracic Society Sleep Core Curriculum updates clinicians on important sleep topics, presented during the annual meeting, and appearing in summary here. This year’s sleep core theme is sleep-disordered breathing and its management. Topics range from pathophysiological mechanisms for the association of obstructive sleep apnea (OSA) and metabolic syndrome, surgical modalities of OSA treatment, comorbid insomnia and OSA, central sleep apnea, and sleep practices during a pandemic. OSA has been associated with metabolic syndrome, independent of the role of obesity, and the pathophysiology suggests a role for sleep fragmentation and intermittent hypoxia in observed metabolic outcomes. In specific patient populations, surgical treatment modalities for OSA have demonstrated large reductions in objective disease severity compared with no treatment and may facilitate adherence to positive airway pressure treatment. Patient-centered approaches to comorbid insomnia and sleep apnea include evaluating for both OSA and insomnia simultaneously and using shared-decision making to determine the order and timing of positive airway pressure therapy and cognitive behavioral therapy for insomnia. The pathophysiology of central sleep apnea is complex and may be due to the loss of drive to breathe or instability in the regulatory pathways that control ventilation. Pandemic-era sleep practices have evolved rapidly to balance safety and sustainability of care for patients with sleep-disordered breathing.

Use of Actigraphy (Wearable Digital Sensors to Monitor Activity) in Heart Failure Randomized Clinical Trials: A Scoping Review

BACKGROUND

Actigraphy-based measurements of physiologic parameters may enable design of patient-centric heart failure (HF) clinical trials. Recently, the Heart Failure Collaboratory focused on recommendations for meaningful change and use of actigraphy as an end point in HF clinical trials. We aimed to evaluate randomized controlled trials (RCTs) that have quantified the impact of HF interventions using actigraphy.

METHODS

Using a scoping review strategy, we evaluated the use of actigraphy in HF RCTs. Studies were identified through electronic searches of Embase, OVID Medline, PubMed, and Cochrane Review. Data on trial characteristics and results were collected.

RESULTS

We identified 11 RCTs with a total of 1,455 participants. The risk of bias across the included trials was high overall. All trials had the primary outcomes reflecting measures of either physical activity (n = 8), sleep (n = 2), or both (n = 1). Five trials evaluated response to pharmacologic therapies compared with placebo, 3 evaluated physical activity interventions, 2 evaluated group or cognitive therapy, and 1 evaluated sleep-ventilation strategy. Sample sizes ranged from 30 to 619 participants. There was significant heterogeneity relating to device type, body placement site, and handling of missing actigraphy data. Duration of monitoring ranged from 48 hours to 12 weeks. None of the studies evaluating pharmacologic therapies (n = 5) demonstrated a significant improvement of actigraphy-based primary end point measurements.

CONCLUSIONS

There is significant heterogeneity in the use, methodology, and results of actigraphy-based HF RCTs. Our results highlight the need to develop, standardize, and validate actigraphy-specific outcomes for use in HF clinical trials.

Novel technologies in the management of heart failure with preserved ejection fraction: a promise during the time of disappointment from pharmacological approaches?

PURPOSE OF REVIEW

Despite numerous attempts, none of a wide variety of tested drugs achieved meaningful improvement in the outcomes of heart failure with preserved ejection fraction (HFpEF), making new therapeutic strategies a major unmet medical need. The medical device industry embraced the challenge, developing novel technologies directed to face specific aspects of the pathophysiology of HFpEF. This review focuses on some of the most promising technologies attaining meaningful clinical progress recently in the field of HFpEF therapy.

RECENT FINDINGS

Implantable pulmonary artery pressure, monitoring for optimization of medical therapy, proved to be beneficial in heart failure admissions in a large postmarketing clinical study. Investigational devices, such as inter-atrial shunts and transvenous phrenic nerve stimulators for the treatment of central sleep apnea with Cheyne-Stokes breathing, are currently being evaluated in HFpEF cohorts in recent trials.

SUMMARY

Device-based therapies for HFpEF demonstrated encouraging safety and efficacy results in various stages of the disease. Further efforts are needed to ensure that these devices will reach clinical use and contribute to the management of HFpEF patients.

A Mouse Model Suggests That Heart Failure and Its Common Comorbidity Sleep Fragmentation Have No Synergistic Impacts on the Gut Microbiome

Heart failure (HF) is a common condition associated with a high rate of hospitalizations and adverse outcomes. HF is characterized by impairments of either the cardiac ventricular filling, ejection of blood capacity or both. Sleep fragmentation (SF) involves a series of short sleep interruptions that lead to fatigue and contribute to cognitive impairments and dementia. Both conditions are known to be associated with increased inflammation and dysbiosis of the gut microbiota. In the present study, mice were distributed into four groups, and subjected for four weeks to either HF, SF, both HF and SF, or left unperturbed as controls. We used 16S metabarcoding to assess fecal microbiome composition before and after the experiments. Evidence for distinct alterations in several bacterial groups and an overall decrease in alpha diversity emerged in HF and SF treatment groups. Combined HF and SF conditions, however, showed no synergism, and observed changes were not always additive, suggesting preliminarily that some of the individual effects of either HF or SF cancel each other out when applied concomitantly.

Subclinical left ventricular systolic dysfunction detected in obstructive sleep apnea with automated function imaging and its association with nocturnal hypoxia

BACKGROUND

Early detection of left ventricular (LV) dysfunction is crucial in obstructive sleep apnea (OSA) due to its close relationship with cardiovascular diseases. Global longitudinal strain (GLS) derived from automated function imaging (AFI) can precisely assess global longitudinal function. The aim of this study was to determine if LV GLS was reduced in patients with OSA and a normal LV ejection fraction (LVEF) and to assess any associated determinants.

METHODS

Polysomnography (PSG) and echocardiography were done in consecutive patients with suspected OSA and normal LVEF in this prospective study. Patients were divided into two groups according to apnea-hypopnea index (AHI) (Group 1, normal or mild OSA: AHI < 15/h; Group 2, moderate-to-severe OSA: AHI ≥ 15/h). Clinical, PSG, and echocardiographic parameters were compared between the two groups and the associated factors were investigated.

RESULTS

Of 425 consecutive patients, 244 were analyzed after exclusions. Patients in Group 2 had significantly worse GLS than those in Group 1 (p < 0.001). The prevalence of GLS reduction (defined as < - 19.7%) was 25% and 76%, respectively (χ² = 34.19, p < 0.001). Nocturnal lowest pulse oxygen saturation (SpO₂), AHI, body mass index (BMI), and gender were associated with GLS reduction (all p < 0.05). Further multivariate analysis showed that the lowest SpO₂ (OR: 2.15), gender (OR: 2.45), and BMI (OR: 2.66) remained independent (all p < 0.05), and the lowest SpO₂ was the most powerful determinant (χ² = 33.0, p < 0.001) in forward regression analysis. The intra- and inter-operator variability for AFI and coefficient of repeatability was low even in those with relatively poor images.

CONCLUSIONS

In patients with normal LVEF, more severe OSA was associated with a worse GLS. The major determinants were lowest nocturnal SpO₂, gender, and obesity, but not AHI. GLS can be rapidly and reliably assessed using AFI.

Undiagnosed sleep apnoea in cardiac rehabilitation: Age-dependent effect on diastolic function in coronary artery disease patients with preserved ejection fraction

BACKGROUND

Focusing on detection of sleep apnoea early in the cardiac rehabilitation process may improve the recovery process and reduce recurrence of cardiovascular events. Patients who continue to be undiagnosed may experience a significantly worse outcome during their cardiac rehabilitation and recovery. Diastolic dysfunction has both diagnostic and prognostic importance in the management of coronary artery disease. We hypothesise that undiagnosed/untreated sleep apnoea in middle-aged coronary artery disease patients with preserved left ventricular ejection fraction changes the pattern of diastolic filling close to that in elderly patients without sleep apnoea.

METHODS AND RESULTS

This cross-sectional study included the 450 coronary artery disease patients with undiagnosed sleep apnoea who had left ventricular ejection fraction ⩾50% and were referred consecutively to the Clinic of Cardiovascular Rehabilitation within two weeks after treatment for acute coronary syndrome. Polysomnographic and echocardiographic measurements were analysed. Mild to severe sleep apnoea was defined as the apnoea-hypopnea index ⩾5. Age was dichotomised into under the age of 60 years and age 60 years or over. Up to 35% of coronary artery disease patients were likely to have undiagnosed sleep apnoea. There was a statistically significant interaction between the effect of sleep apnoea and age group on diastolic function defined as the ratio peak flow velocity in early diastole/peak flow velocity in atrial contraction ratio (p=0.036). This ratio was significantly (p=0.029) lower in the mild-severe sleep apnoea group (0.97, 95% confidence interval 0.88-1.06) than in the non-sleep apnoea group (1.09, 95% confidence interval 1.03-1.15) among middle aged (<60 years) coronary artery disease patients. Therefore, filling patterns in the middle aged (<60 years) patients with sleep apnoea resemble those observed in the elderly (⩾60 years) patients without sleep apnoea. The effect of sleep apnoea on left ventricular filling pattern in elderly was not observed.

CONCLUSIONS

Age modifies the effect of sleep apnoea on cardiovascular outcomes. The findings that undiagnosed sleep apnoea impairs diastolic function in a middle-aged coronary artery disease patient underscore the importance of early diagnosis and treatment of sleep apnoea. It is recommended to train and educate cardiac rehabilitation staff on the importance of sleep disorders in this population.

Inhibition of Brainstem Endoplasmic Reticulum Stress Rescues Cardiorespiratory Dysfunction in High Output Heart Failure

Recent evidence shows that chronic activation of catecholaminergic neurons of the rostral ventrolateral medulla is crucial in promoting autonomic imbalance and cardiorespiratory dysfunction in high output heart failure (HF). Brainstem endoplasmic reticulum stress (ERS) is known to promote cardiovascular dysfunction; however, no studies have addressed the potential role of brainstem ERS in cardiorespiratory dysfunction in high output HF. In this study, we assessed the presence of brainstem ERS and its potential role in cardiorespiratory dysfunction in an experimental model of HF induced by volume overload. High output HF was surgically induced via creation of an arterio-venous fistula in adult male Sprague-Dawley rats. Tauroursodeoxycholic acid (TUDCA), an inhibitor of ERS, or vehicle was administered intracerebroventricularly for 4 weeks post-HF induction. Compared with vehicle treatment, TUDCA improved cardiac autonomic balance (LF_HRV/HF_HRV ratio, 3.02±0.29 versus 1.14±0.24), reduced cardiac arrhythmia incidence (141.5±26.7 versus 35.67±12.5 events/h), and reduced abnormal respiratory patterns (Apneas: 11.83±2.26 versus 4.33±1.80 events/h). TUDCA administration (HF+Veh versus HF+TUDCA, P<0.05) attenuated cardiac hypertrophy (HW/BW 4.4±0.3 versus 4.0±0.1 mg/g) and diastolic dysfunction. Analysis of rostral ventrolateral medulla gene expression confirmed the presence of ERS, inflammation, and activation of renin-angiotensin system pathways in high output HF and showed that TUDCA treatment completely abolished ERS and ERS-related signaling. Taken together, these results support the notion that ERS plays a role in cardiorespiratory dysfunction in high output HF and more importantly that reducing brain ERS with TUDCA treatment has a potent salutary effect on cardiac function in this model.

Standardized definitions for evaluation of heart failure therapies: scientific expert panel from the Heart Failure Collaboratory and Academic Research Consortium

The Heart Failure Academic Research Consortium is a partnership between the Heart Failure Collaboratory (HFC) and Academic Research Consortium (ARC), comprised of leading heart failure (HF) academic research investigators, patients, United States (US) Food and Drug Administration representatives, and industry members from the US and Europe. A series of meetings were convened to establish definitions and key concepts for the evaluation of HF therapies including optimal medical and device background therapy, clinical trial design elements and statistical concepts, and study endpoints. This manuscript summarizes the expert panel discussions as consensus recommendations focused on populations and endpoint definitions; it is not exhaustive or restrictive, but designed to stimulate HF clinical trial innovation.

The central nervous system and heart failure

The view that chronic heart failure was exclusively a disease of the heart dominated the cardiovascular literature until relatively recently. However, over the last 40 years it has increasingly come to be seen as a multisystem disease. Aside from changes in the sympathetic and parasympathetic nervous systems and the renin-angiotensin-aldosterone system, adaptations to the lungs, muscles and gastrointestinal tract have been clearly documented. It is clear that the brain and CNS are also affected in patients with heart failure, although this is often under recognized. The purpose of this review is to summarize the changes in the structure and biochemical function of the CNS in patients with chronic heart failure and to discuss their potential importance.

Chronic Sleep Fragmentation Mimicking Sleep Apnea Does Not Worsen Left-Ventricular Function in Healthy and Heart Failure Mice

Aims: Obstructive sleep apnea (OSA) has been associated with heart failure (HF). Sleep fragmentation (SF), one of the main hallmarks of OSA, induces systemic inflammation, oxidative stress and sympathetic activation, hence potentially participating in OSA-induced cardiovascular consequences. However, whether SF per se is deleterious to heart function is unknown. The aim of this study was to non-invasively evaluate the effect of SF mimicking OSA on heart function in healthy mice and in mice with HF. Methods and Results: Forty C57BL/6J male mice were randomized into 4 groups: control sleep (C), sleep fragmentation (SF), isoproterenol-induced heart failure (HF), and mice subjected to both SF+HF. Echocardiography was performed at baseline and after 30 days to evaluate left ventricular end-diastolic (LVEDD) and end-systolic (LVESD) diameters, left ventricular ejection fraction (LVEF) and fraction shortening (FS). The effects of SF and HF on these parameters were assessed by two-way ANOVA. Mice with isoproterenol-induced HF had significant increases in LVEDD and LVESD, as well as a decreases in LVEF and FS (p = 0.013, p = 0.006, p = 0.027, and p = 0.047, respectively). However, no significant effects emerged with SF (p = 0.480, p = 0.542, p = 0.188, and p = 0.289, respectively). Conclusion: Chronic SF mimicking OSA did not induce echocardiographic changes in cardiac structure and function in both healthy and HF mice. Thus, the deleterious cardiac consequences of OSA are likely induced by other perturbations associated with this prevalent condition, or result from interactions with underlying comorbidities in OSA patients.

Sleep Apnea and Heart Failure With a Reduced Ejection Fraction Among Persons Living With Human Immunodeficiency Virus

Background

Sleep apnea (SA) is common and has prognostic significance among broad groups of patients with heart failure (HF). There are no data characterizing the presence, associations, and prognostic significance of SA among persons living with human immunodeficiency virus (PLHIV) with HF.

Methods

We conducted a single-center study of PLHIV with HF with reduced ejection fraction (HFrEF; left ventricular ejection fraction [LVEF] <50%) and analyzed the relationship of SA with 30-day HF hospital readmission rate.

Results

Our cohort included 1124 individuals admitted with HFrEF; 15% were PLHIV, and 92% were on antiretroviral therapy. SA was noted in 28% of PLHIV and 26% of uninfected controls. Compared to uninfected controls with HFrEF and SA, PLHIV with HFrEF and SA had a lower body mass index, lower LVEF, a higher pulmonary artery systolic pressure (PASP), were more likely to have obstructive rather than central SA (P < .05 for all). In a multivariable model, PASP, low CD4 count, high viral load (VL), and SA parameters (apnea-hypopnea index, CPAP use and duration) were predictors of 30-day HF readmission rate. Each 1-hour increase in CPAP use was associated with a 14% decreased risk of 30-day HF readmission among PLHIV.

Conclusions

Compared to uninfected controls, PLHIV were more likely to have obstructive SA than central SA. Apnea severity, low CD4 count, high VL, and cocaine use were positively associated with 30-day HF hospital readmission rate, whereas CPAP use and increased duration of CPAP use conferred protection.

Acetazolamide as a potent chloride-regaining diuretic: short- and long-term effects, and its pharmacologic role under the 'chloride theory' for heart failure pathophysiology

According to the "chloride theory" for heart failure (HF) pathophysiology, manipulation of the serum chloride concentration is an important therapeutic target. This study determined the short- and long-term effects of acetazolamide (Diamox), a potential chloride-regaining diuretic, on peripheral blood, serum electrolytes, and renal function. Effects of low-dose Diamox (250-500 mg/day) were evaluated in 30 HF patients for whom Diamox was added as de-novo/add-on decongestion therapy for acutely worsening HF (n = 18) or as modification therapy for serum hypochloremia in stable HF ( < 100 mEq/L; n = 12). Peripheral hematologic tests were performed at baseline, and at short- ( ≤ 10 days) and long-term ( ~ 60 days) time-points. In all 30 study patients of both groups, the serum chloride concentration increased in the short-term and even further over the long-term. The serum potassium concentration constantly decreased throughout the study period. Both the blood urea nitrogen and serum creatinine concentrations increased in the short-term, but returned to baseline levels over the long-term. Responders to Diamox (n = 13; defined by HF resolution and body weight loss ≥ 1 kg) in the decongestion group exhibited reduced serum b-type natriuretic peptide levels and a markedly increased serum chloride concentration, but the hemoglobin/hematocrit and serum creatinine concentrations did not change after treatment. In conclusion, acetazolamide is a potent candidate "chloride-regaining diuretic" for treating HF patients under the "chloride theory". Its effect to enhance the serum chloride concentration occurred within 10 days and persisted for at least ~ 60 days. Plasma volume and renal function were preserved under adequate diuretic treatment with acetazolamide.

The Influence of Sleep Apnea on 24-Hour and Nocturnal ECG and Blood Pressure Parameters in Patients with Acute Heart Failure

OBJECTIVE

To investigate the influence of sleep apnea (SA) on ECG and blood pressure (BP) monitoring parameters in patients with acute heart failure (AHF).

METHODS

A total of 51 hospitalized patients with AHF (13 women, 38 men, mean age 60.8 years) underwent 24-hour combined monitoring of ECG and BP and SA testing before discharge. Heart rhythm (mean heart rate, arrhythmias, pauses, QT interval, heart rate variability) and BP (mean systolic and diastolic values, variability, circadian variation) parameters were obtained for the whole day and for nighttime (22: 00-06: 00). Depending on SA severity, the patients were divided into two groups (respiratory event index, REI, < 15/h and ≥15/h). Comparisons of parameters between the two groups were performed using t test and χ2 test (alpha < 0.05 for significance).

RESULTS

A total of 29 (56.9%) patients had REI ≥15/h. In this group, the systolic and diastolic BP values (24-hour and nighttime) were significantly higher (p < 0.05). BP variability did not differ, and a markedly blunted circadian variation of both the systolic and diastolic values was observed. In the group with REI ≥15/h, we found a higher nocturnal versus diurnal mean heart rate ratio (p = 0.046) and a greater occurrence of nocturnal versus diurnal ventricular premature beats (p = 0.0098).

CONCLUSION

The presence of significant SA was found to influence the BP values and nocturnal ventricular ectopy in patients with stabilized AHF. SA, 24-hour ECG, and BP monitoring could provide important information with potential impact on patient management.

Cognitive impairment predicts mortality in outpatient veterans with heart failure

BACKGROUND

In our prior study of 250 outpatient veterans with heart failure (HF), 58% had unrecognized cognitive impairment (CI) which was linked to worsened medication adherence. Literature suggests HF patients with CI have poorer clinical outcomes including higher mortality.

OBJECTIVE

The study is to examine mortality rates in outpatients with HF and undiagnosed CI compared to their cognitively intact peers.

METHODS

This is a retrospective study for all-cause mortality.

RESULTS

During the 3-year follow up, 64/250 (25.6%) patients died: 20/106 (18.9%) with no CI, 29/104 (27.9%) with mild CI, and 15/40 (37.5%) with severe CI. Patients with CI were at increased risk for mortality (hazard ratio 1.82, p = 0.038). Those with severe CI had the worst outcome (hazard ratio 2.710, p = 0.011).

CONCLUSIONS

CI was an independent risk factor for mortality in patients with heart failure when controlling for age and markers of disease severity. Cognitive screening should be performed routinely to identify patients at greater risk for adverse outcomes.