Cheyne-Stokes Respiration In Patients Research Articles

Abstract 12026: Correlates of Sleep Disordered Breathing and Cheyne-Stokes Respiration in Patients With Atrial Fibrillation Undergoing Pulmonary Vein Isolation

Background: Sleep disordered breathing (SDB) is known as a common comorbidity in patients with atrial fibrillation (AF). Indeed, patients undergoing pulmonary vein isolation (PVI) for AF had a high prevalence of SDB in particular, Cheyne-Stokes respiration (CSR). The aim of the present study is to assess the correlates of SDB severity and CSR in AF patients undergoing PVI. Methods and Results: The study was conducted under a single-center, observational design. We enrolled 140 consecutive patients undergoing PVI. All participants underwent home sleep apnea test (ApneaLink Air, ResMed, Australia) which could determine the severity of SDB as assessed by apnea-hypopnea index (AHI) and the percent of CSR (%CSR) pattern. Overall, 33 (27.9%) patients was no SDB (AHI<5), 53 (37.9%) patients was mild SDB (5≦AHI<15), 33 (23.6%) patients was moderate SDB (15≦AHI<30), and 15 (10.7%) patients was severe SDB(30≦AHI). Correlates of the increased AHI includes male sex (β=0.27, p=0.001), high age (β=0.19, p=0.0028), high body mass index (BMI) (β=0.29, p=0.0013), hypertension (β=0.18, p=0.038), and non-paroxysmal AF (β=0.17, p=0.047). On the other hand, correlates to %CSR rate includes male sex (β=0.17, p=0.026), high age (β=0.22, p=0.0054), non-paroxysmal AF (β=0.27, p=0.0005), high value of HbA1c (β=0.3, p<0.0001), and greater N-terminal fragment of the Brain natriuretic peptide (NT-proBNP) (β=0.26, p=0.0007). Conclusion: Increased SDB severity correlated with male sex, high age, obesity, hypertension and chronicity of AF in patients with PVI. Correlates the percent of %CSR were male sex, high age, the chronicity of AF, high value of HbA1c, and greater NT-proBNP. Treatment for SDB should be consider for these AF patients, because SDB increases the recurrence ratio of AF after PVI.

Periodic breathing in patients with stable obstructive sleep apnea on long-term continuous positive airway pressure treatment: a retrospective study using CPAP remote monitoring data

PurposeThe purpose of this study was to investigate the rate of periodic breathing (PB) and factors associated with the emergence or persistence of PB in patients with obstructive sleep apnea (OSA) by continuous positive airway pressure (CPAP) remote monitoring data.MethodsThis was a retrospective cohort study on 775 patients who had used the same model CPAP machine for at least 1 year as of September 1, 2020. The data were analyzed online using the dedicated analysis system. Using exporter software, average apnea/hypopnea index (AHI), average central apnea index (CAI), and average the rate of PB time (PB%) were cited.ResultsAmong 618 patients analyzed (age 61.7 ± 12.2 years, male 89%, BMI 27.2 ± 4.9), the average duration of CPAP use was 7.5 ± 4.0 years. The median PB% in stable patients was low at 0.32%, and only 149 patients (24%) had a PB% above 1%. Multiple regression analysis of factors for the development of PB showed that the most important factor was atrial fibrillation (Af) with a coefficient of 0.693 (95% CI; 0.536 to 0.851), followed by QRS duration with a coefficient of 0.445 (95% CI; 0.304 to 0.586), followed by history of heart failure, male sex, comorbid hypertension, obesity, and age. The average PB% for paroxysmal Af was significantly lower than that for persistent and permanent Af.ConclusionsThe median PB% in stable patients on CPAP treatment was low at 0.32%, with only 24% of patients having PB% ≥ 1%. Persistent Af and an increase in QRS duration were found to be important predictors of increased PB%.Clinical trial registrationUMIN000042555 2021/01/01.

Sleep-disordered breathing in patients with chronic heart failure before and after heart transplantation

Objective: To explore the characteristics of sleep-disordered breathing (SDB) in chronic heart failure patients waiting for heart transplantation and the changes of SDB after transplantation. Methods: From September 2018 to December 2019, 34 patients with chronic heart failure were prospectively enrolled into this study, who were hospitalized for waiting for heart transplantation in the departments of cardiovascular medicine and cardiovascular surgery, Renmin Hospital of Wuhan University. All of them received portable sleep physiological monitoring. The characteristics of their SDB were analyzed before and after heart transplantation. Results: Of the 34 patients waiting for heart transplantation, 22 had central sleep apnea, 4 had obstructive sleep apnea and 8 had no SDB. The cycle length of Cheyne-Stokes respiration was negatively correlated with left ventricular ejection fraction. After heart transplantation, 15 patients received repeat sleep physiological monitoring and their results showed that the SDB was significantly improved, with the elimination of Cheyne-Stokes respiration. Conclusions: Patients waiting for heart transplantation had a high prevalence of SDB, with Cheyne-Stokes respiration with central sleep apnea as the main type. However, heart transplantation may eliminate the Cheyne-Stokes respiration in patients with chronic heart failure.

Prospects for the treatment of central sleep apnea and Cheyne-Stokes respiration in heart failure

The risk factors, clinical manifestations, pathophysiology, diagnosis and treatment options for central sleep apnea and Cheyne-Stokes respiration in patients with heart failure are highlighted in this review. The effectiveness and prospects of therapeutic approaches are discussed: CPAP therapy, adaptive servo ventilation, transvenous stimulation of the phrenic nerve.

Prevalence and risk factors of Cheyne-Stokes respiration in patients with chronic heart failure with reduced left ventricular ejection fraction

Prevalence and risk factors of Cheyne-Stokes respiration in patients with chronic heart failure with reduced left ventricular ejection fraction

First Description of the Hyperpnea-Hypopnea Periodic Breathing in Patients with Interstitial Lung Disease-Obstructive Sleep Apnea: Treatment Implications in a Real-Life Setting.

There is evidence that hypopneas are more common than apneas in obstructive sleep apnea (OSA) related to idiopathic pulmonary fibrosis (IPF). We investigated the frequency distribution of hypopneas in 100 patients with interstitial lung diseases (ILDs) (mean age 69 yrs ± 7.8; 70% males), including 54 IPF cases, screened for OSA by home sleep testing. Fifty age- and sex-matched pure OSA patients were included as controls. In ILD-OSA patients the sleep breathing pattern was characterized by a high prevalence of hypopneas that were preceded by hyperpnea events configuring a sort of periodic pattern. This finding, we arbitrarily defined hyperpnea–hypopnea periodic breathing (HHPB), was likely reflecting a central event and was completely absent in control OSA. Also, the HHPB was highly responsive to oxygen but not to the continuous positive pressure support. Thirty-three ILD-OSA patients (42%) with a HHPB associated with a hypopnea/apnea ratio ≥3 had the best response to oxygen with a median residual AHI of 2.6 (1.8–5.6) vs. 28.3 (20.7–37.8) at baseline (p < 0.0001). ILD-OSA patients with these characteristics were similarly distributed in IPF (54.5%) and no-IPF cases (45.5%), the most of them being affected by moderate–severe OSA (p = 0.027). Future studies addressing the pathogenesis and therapy management of the HHPB should be encouraged in ILD-OSA patients.

P4706Phase-related variations in cardiopulmonary hemodynamics throughout cheyne-stokes respiration in patients with heart failure

P4706Phase-related variations in cardiopulmonary hemodynamics throughout cheyne-stokes respiration in patients with heart failure

Distinct Patterns of Hyperpnea During Cheyne-Stokes Respiration: Implication for Cardiac Function in Patients With Heart Failure.

In heart failure (HF), we observed two patterns of hyperpnea during Cheyne-Stokes respiration with central sleep apnea (CSR-CSA): a positive pattern where end-expiratory lung volume remains at or above functional residual capacity, and a negative pattern where it falls below functional residual capacity. We hypothesized the negative pattern is associated with worse HF. Patients with HF underwent polysomnography. During CSR-CSA, hyperpnea, apnea-hyperpnea cycle, and lung to finger circulation times (LFCT) were measured. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentration and left ventricular ejection fraction (LVEF) were assessed. Of 33 patients with CSR-CSA (31 men, mean age 68 years), 9 had a negative hyperpnea pattern. There was no difference in age, body mass index, and apnea-hypopnea index between groups. Patients with a negative pattern had longer hyperpnea time (39.5 ± 6.4 versus 25.8 ± 5.9 seconds, P < .01), longer cycle time (67.8 ± 15.9 versus 51.7 ± 9.9 seconds, P < .01), higher NT-proBNP concentrations (2740 [6769] versus 570 [864] pg/ml, P = .01), and worse New York Heart Association class (P = .02) than those with a positive pattern. LFCT and LVEF did not differ between groups. Patients with HF and a negative CSR-CSA pattern have evidence of worse cardiac function than those with a positive pattern. Greater positive expiratory pressure during hyperpnea is likely generated during the negative pattern and might support stroke volume in patients with worse cardiac function. A commentary on this article appears in this issue on page 1227. The trial is registered with Current Controlled Trials (www.controlled-trials.com; ISRCTN67500535) and Clinical Trials (www.clinicaltrials.gov; NCT01128816).

Treatment of Cheyne-Stokes respiration in patients with heart failure with reduced ejection fraction – Registry

Treatment of Cheyne-Stokes respiration in patients with heart failure with reduced ejection fraction – Registry

Resonance as the Mechanism of Daytime Periodic Breathing in Patients with Heart Failure

In patients with chronic heart failure, daytime oscillatory breathing at rest is associated with a high risk of mortality. Experimental evidence, including exaggerated ventilatory responses to CO2 and prolonged circulation time, implicates the ventilatory control system and suggests feedback instability (loop gain > 1) is responsible. However, daytime oscillatory patterns often appear remarkably irregular versus classic instability (Cheyne-Stokes respiration), suggesting our mechanistic understanding is limited. We propose that daytime ventilatory oscillations generally result from a chemoreflex resonance, in which spontaneous biological variations in ventilatory drive repeatedly induce temporary and irregular ringing effects. Importantly, the ease with which spontaneous biological variations induce irregular oscillations (resonance "strength") rises profoundly as loop gain rises toward 1. We tested this hypothesis through a comparison of mathematical predictions against actual measurements in patients with heart failure and healthy control subjects. In 25 patients with chronic heart failure and 25 control subjects, we examined spontaneous oscillations in ventilation and separately quantified loop gain using dynamic inspired CO2 stimulation. Resonance was detected in 24 of 25 patients with heart failure and 18 of 25 control subjects. With increased loop gain-consequent to increased chemosensitivity and delay-the strength of spontaneous oscillations increased precipitously as predicted (r = 0.88), yielding larger (r = 0.78) and more regular (interpeak interval SD, r = -0.68) oscillations (P < 0.001 for all, both groups combined). Our study elucidates the mechanism underlying daytime ventilatory oscillations in heart failure and provides a means to measure and interpret these oscillations to reveal the underlying chemoreflex hypersensitivity and reduced stability that foretells mortality in this population.

Implications of revised AASM rules on scoring apneic and hypopneic respiratory events in patients with heart failure with nocturnal Cheyne-Stokes respiration.

This study investigated the implications of the revised scoring rules of the American Academy of Sleep Medicine (AASM) in patients with heart failure (HF) with Cheyne-Stokes respiration (CSR). Ninety-one patients (NYHA ≥II, LVEF ≤45%; age 73.6 ± 11.3years old; 81 male subjects) with documented CSR underwent 8h of cardiorespiratory polygraphy recordings. Those were analyzed by a single scorer strictly applying the 2007 recommended, 2007 alternative, and the 2012 scoring rules. Compared with the AASM 2007 recommended rules, apnea-hypopnea index (AHI) and hypopnea index (HI) increased significantly when the 2007 alternative and 2012 rules were applied (AHI 34.1 ± 13.5/h vs 37.6 ± 13.2/h vs 38.3 ± 13.2/h, respectively; HI 10.2 ± 9.4/h vs 13.7 ± 10.7/h vs 14.4 ± 11.0/h, respectively; all p < 0.001). Duration of CSR increased significantly with the alternate versus recommended 2007 rules (182.2 ± 117.0 vs 170.1 ± 115.0min; p ≤ 0.001); there was a significant decrease in CSR duration for the 2012 versus 2007 alternative rules (182.2 ± 117.0 vs 166.7 ± 115.4min; p ≤ 0.001). AHI was higher using the AASM 2012 scoring rules due to a less strict definition of hypopnea. Data on the prognostic effects of CSR in patients with HF and the benefits of treatment are mostly based on the AASM 2007 recommended rules, so differences between these and the newer version need to be taken into account.

The Relationship between Nocturnal Hypoxemia and Left Ventricular Ejection Fraction in Congestive Heart Failure Patients

Congestive heart failure (CHF) is a major cause of mortality and morbidity. Among patients with heart failure, sleep disordered breathing (SDB) is a common problem. Current evidence suggests that SDB, particularly central SDB, is more prevalent in patients with CHF than in the general population, but it is underdiagnosed as SDB symptoms that are less prevalent in CHF. The main aims of this study were to determine the relationship between nocturnal hypoxemia and left ventricular ejection fraction in patients with chronic heart failure. By means of echocardiography, 108 patients with left ventricular ejection fraction ≤45% were divided into mild, moderate, and severe CHF. Hypoxemia was recorded overnight in the hospital and was measured by portable pulse oximetry. In the 108 patients with CHF, 44 (40.7%) were severe, 17 (15.7%) moderate, and 47 (43.6%) mild CHF. 95 (88%) of patients with CHF had abnormal patterns of nocturnal hypoxemia suggestive of Cheyne-Stokes respiration. Ejection fraction correlated negatively with dip frequency. There was no correlation between nocturnal hypoxemia with BMI and snoring. This study confirms strong associations between sleep apnea and heart disease in patients with CHF. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

Clinical characteristics of hospitalized heart failure patients with daytime cheyne-stokes respiration

Introduction Cheyne-Stokes respiration (CSR) frequently occurs in patients with heart failure (HF). CSR in HF patients is important because it may independently predict morbidity and mortality due to HF. In previous analyses of HF patients, CSR was observed not only in the nighttime but also in the daytime. Moreover, daytime CSR may also predict worse prognosis in HF patients. Most of these studies have evaluated HF patients only on chronic phase. Daytime CSR in patients with HF on sub-acute phase (during hospitalization) remains unknown. We therefore investigated prevalence and clinical characteristics of daytime CSR in hospitalized patients with worsening of HF. Materials and methods In consecutive patients who were hospitalized due to worsening of HF, breathing pattern was monitored with a portable respiratory polygraph continuously over 24 h after their condition was stabilized. The monitor comprised sensors for airflow and for respiratory effort and a pulse oximeter finger sensor. Body weight and blood test data were collected simultaneously. Results 28 HF patients were enrolled (age, 71.1_ plus/minus 11.4 years; 9 women; LVEF, 51.8_ plus/minus 15.1 %). Daytime CSR was highly prevalent (N = 22, 78.6%). In the nighttime, frequency of apneas and hypopneas per hour of recording expressed as nighttime apnea- hypopnea index (nAHI) was 19.0_ plus/minus 10.5 whereas AHI in the daytime (dAHI) was 8.8_ plus/minus 5.7. The patients were divided into two groups according to median value of the dAHI: higher dAHI group (dAHI ⩾ 8.4) and lower dAHI group (dAHI 8.4). We found no significant differences between two groups in baseline characteristics including age, sex, body mass index, plasma brain natriuretic peptide level, LVEF, New York Heart Association class, PaCO2 and the presence of atrial fibrillation or ischemic heart disease (IHD). We only found significant difference in lung-to-finger circulation time (LFCT) between two groups (38.0 vs 24.0 s; p 0.001) despite no difference in other cardiac parameters.In addition, LFCT was correlated with dAHI (r = 0.71, p 0.0001). LFCT was longer in men (men vs women, 33.8 vs 24.9 s, p 0.05) and patients with IHD (36.5 vs 26.5 s, p 0.01). Conclusion Daytime CSR is frequent in hospitalized patients with HF and is correlated with prolonged LFCT. Prolonged LFCT, which indicates impaired cardiac output, has an adverse effect on survival. Therefore, significant daytime CSR in hospitalized patients with HF might be a predictor of increased morbidity and mortality. Acknowledgements We express gratitude to all those who participated in this study.

Sleep-wake fluctuations and respiratory events during Cheyne-Stokes respiration in patients with heart failure

Fluctuations in sleep-wake state are thought to contribute to the respiratory instability of Cheyne-Stokes respiration in patients with heart failure by promoting the rhythmic occurrence of central apnea and ventilatory overshoot. There are no data, however, on the relationship between vigilance state and respiratory events. In this study we used a novel method to detect the occurrence of state transitions (time resolution: 0.25s, minimum duration of state changes: 2s) and to assess their time relationship with apnoeic events. We also evaluated whether end-apnoeic arousals are associated with a ventilatory overshoot. A polysomnographic, daytime laboratory recording (25min) was performed during Cheyne-Stokes respiration in 16 patients with heart failure. Automatic state classification included wakefulness and non-rapid eye movement sleep stages 1-2. As a rule, wakefulness occurred during hyperpnoeic phases, and non-rapid eye movement sleep occurred during apnoeic events. Ninety-two percent of the observed central apneas (N=272) were associated with a concurrent wakefulness → non-rapid eye movement sleep → wakefulness transition. The delay between wakefulness → non-rapid eye movement sleep transitions and apnea onset was -0.3 [-3.1, 3.0]s [median (lower quartile, upper quartile); P=0.99 testing the null hypothesis: median delay=0], and the delay between non-rapid eye movement sleep→wakefulness transitions and apnea termination was 0.2 [-0.5, 1.2]s (P=0.7). A positive/negative delay indicates that the state transition occurred before/after the onset or termination of apnea. Non-rapid eye movement sleep→wakefulness transitions synchronous with apnea termination were associated with a threefold increase in tidal volume and a twofold increase in ventilation (all P<0.001), indicating ventilatory overshoot. These findings highlight that wakefulness→non-rapid eye movement sleep → wakefulness transitions parallel apnoeic events during Cheyne-Stokes respiration in patients with heart failure. The relationships between state changes and respiratory events are consistent with the notion that state fluctuations promote ventilatory instability.

Treatment of Cheyne‐Stokes Respiration Reduces Arrhythmic Events in Chronic Heart Failure

This study aimed to investigate whether adequate treatment of Cheyne-Stokes respiration (CSR) reduces the risk of arrhythmic events in patients with chronic heart failure (CHF). A cohort of 403 registry patients with CHF (LVEF≤45%, NYHA-class≥2) and implanted cardioverter-defibrillator devices (ICD) was studied. They underwent overnight polygraphy, with 221 having mild or no CSR (apnea-hypopnea index [AHI]<15/h), and 182 having moderate to severe CSR (AHI>15/h). Latter ones were offered therapy with adaptive servoventilation (ASV), which 96 patients accepted and 86 rejected. During follow-up (21± 15 months) defibrillator therapies were recorded in addition to clinical and physiologic measures of heart failure severity. Event-free survival from (a) appropriate cardioverter-defibrillator therapies and (b) appropriately monitored ventricular arrhythmias was shorter in the untreated CSR group compared to the treated CSR and the no CSR group. Stepwise Cox proportional hazard regression analysis showed untreated CSR (a: hazard ratio [HR] 1.99, 95% confidence interval [CI] 1.46-2.72, P < 0.001; b: HR 2.19, 95%CI 1.42-3.37, P < 0.001), but not treated CSR (a: HR 1.06, 95%CI 0.74-1.50; P = 0.77; b: HR 1.21, 95%CI 0.75-1.93, P = 0.43) was an independent risk factor. The treated CSR group showed improvements in cardiac function and respiratory stability compared to the untreated CSR group. This study demonstrates a decrease of appropriate defibrillator therapies by ASV treated CSR in patients with CHF and ICD. A reduced exposure to hyperventilation, hypoxia, and improvement in indices of CHF severity and neurohumoral disarrangements are potential causative mechanisms.

Transvenous Phrenic Nerve Stimulation in Patients With Cheyne-Stokes Respiration and Congestive Heart Failure: A Safety and Proof-of-Concept Study

Cheyne-Stokes respiration (CSR), which often occurs in patients with congestive heart failure (CHF), may be a predictor for poor outcome. Phrenic nerve stimulation (PNS) may interrupt CSR in patients with CHF. We report the clinical use of transvenous PNS in patients with CHF and CSR. Nineteen patients with CHF and CSR were enrolled. A single stimulation lead was placed at the junction between the superior vena cava and brachiocephalic vein or in the left-side pericardiophrenic vein. PNS stimulation was performed using Eupnea System device (RespiCardia Inc). Respiratory properties were assessed before and during PNS. PNS was assessed at a maximum of 10 mA. Successful stimulation capture was achieved in 16 patients. Failure to capture occurred in three patients because of dislocation of leads. No adverse events were seen under maximum normal stimulation parameters for an overnight study. When PNS was applied following a series of central sleep apneic events, a trend toward stabilization of breathing and heart rate as well as improvement in oxygen saturation was seen. Compared with pre-PNS, during PNS there was a significant decrease in apnea-hypopnea index (33.8 ± 9.3 vs 8.1 ± 2.3, P = .00), an increase in mean and minimal oxygen saturation as measured by pulse oximetry (89.7% ± 1.6% vs 94.3% ± 0.9% and 80.3% ± 3.7% vs 88.5% ± 3.3%, respectively, all P = .00) and end-tidal CO2 (38.0 ± 4.3 mm Hg vs 40.3 ± 3.1 mm Hg, P = .02), but no significant difference in sleep efficiency (74.6% ± 4.1% vs 73.7% ± 5.4%, P = .36). The preliminary results showed that in a small group of patients with CHF and CSR, 1 night of unilateral transvenous PNS improved indices of CSR and was not associated with adverse events.

Cheyne-Stokes Respiration in Patients with First-Ever Lacunar Stroke

The aim of this single-center prospective study was to assess the presence of Cheyne-Stokes respiration (CSR) and CSR-related variables in 68 consecutive patients with radiologically proven first-ever lacunar stroke undergoing a respiratory sleep study using a portable respiratory polygraph within the first 48 hours of stroke onset. CSR was diagnosed in 14 patients (20.6%). Patients with CSR as compared with those without CSR showed a significantly higher mean (standard deviation, SD) apnea-hypopnea index (AHI) (34.9 (21.7) versus 18.5 (14.4), P = 0.001) and central apnea index (13.1 (13.8) versus 1.8 (3.4), P = 0.0001) as well as higher scores of the Barthel index and the Canadian Neurological scale as a measure of stroke severity, and longer hospital stay. CSR was present in one of each five patients with lacunar stroke. The presence of CSR was associated with a trend towards a higher functional stroke severity and worse prognosis.

Loop Gain As a Means to Predict a Positive Airway Pressure Suppression of Cheyne-Stokes Respiration in Patients with Heart Failure

Patients with heart failure (HF) and Cheyne-Stokes respiration or periodic breathing (PB) often demonstrate improved cardiac function when treatment with continuous positive airway pressure (CPAP) resolves PB. Unfortunately, CPAP is successful in only 50% of patients, and no known factor predicts responders to treatment. Because PB manifests from a hypersensitive ventilatory feedback loop (elevated loop gain [LG]), we hypothesized that PB persists on CPAP when LG far exceeds the critical threshold for stable ventilation (LG = 1). To derive, validate, and test the clinical utility of a mathematically precise method that quantifies LG from the cyclic pattern of PB, where LG = 2π/(2πDR - sin2πDR) and DR (i.e., duty ratio) = (ventilatory duration)/(cycle duration) of PB. After validation in a mathematical model of HF, we tested whether our estimate of LG changes with CPAP (n = 6) and inspired oxygen (n = 5) as predicted by theory in an animal model of PB. As a first test in patients with HF (n = 14), we examined whether LG predicts the first-night CPAP suppression of PB. In lambs, as predicted by theory, LG fell as lung volume increased with CPAP (slope = 0.9 ± 0.1; R(2) = 0.82; P < 0.001) and as inspired-arterial PO(2) difference declined (slope = 1.05 ± 0.12; R(2) = 0.75; P < 0.001). In patients with HF, LG was markedly greater in 8 CPAP nonresponders versus 6 responders (1.29 ± 0.04 versus 1.10 ± 0.01; P < 0.001); LG predicted CPAP suppression of PB in 13/14 patients. Our novel LG estimate enables quantification of the severity of ventilatory instability underlying PB, making possible a priori selection of patients whose PB is immediately treatable with CPAP therapy.

Cheyne-Stokes Respiration in Patients with Heart Failure: Prevalence, Causes, Consequences and Treatments

Cheyne-Stokes respiration (CSR) is characterized by a pattern of cyclic oscillations of tidal volume and respiratory rate with periods of hyperpnea alternating with hypopnea or apnea in patients with heart failure. CSR harms the failing heart through intermittent hypoxia brought about by apnea and hypopnea and recurrent sympathetic surges. CSR impairs the quality of life and increases cardiac mortality in patients with heart failure. Thus, CSR should actively be pursued in patients with severe heart failure. When CSR persists despite optimal therapy of heart failure, noninvasive adaptive servoventilation is currently the most promising treatment.

A hybrid approach for continuous detection of sleep‐wakefulness fluctuations: validation in patients with Cheyne–Stokes respiration

Fluctuations in sleep/wake state have been proposed as an important mechanism contributing to the development of oscillatory breathing patterns, including Cheyne-Stokes respiration in patients with heart failure. In order to properly assess the interactions between changes in state and changes in ventilatory parameters, a methodology capable of continuously and reliably detecting state transitions is needed. Traditional fixed-epoch analysis of polysomnographic recordings is not suitable for this purpose. Moreover, visual identification of changes in the dominant electroencephalogram activity at the transition from wakefulness to sleep and vice versa is often very subjective. We have therefore developed a hybrid approach--including both visual scoring and computer-based procedures--for continuous analysis of state transitions from polysomnographic recordings, specifically tailored for fluctuations between wakefulness and non-rapid eye movement-1 and -2 sleep. The overall analysis process comprises three major phases: (1) manual identification of relevant electroencephalogram/electrooculogram features and events, including a sample of unequivocal alpha and theta-delta activity; (2) automatic statistical discrimination of dominant electroencephalogram activity; and (3) state classification (wakefulness, non-rapid eye movement-1 and -2). The latter is carried out by merging information from visual scoring with the output of the discriminator. Validation has been carried out in 16 patients with heart failure during daytime Cheyne-Stokes respiration, using a training and testing set of electroencephalogram polysomnograms. The statistical discriminator correctly classified 99.1 ± 1.4% and 99.2 ± 1.1% of unequivocal alpha and theta-delta activity. This approach has therefore the potential to be used to reliably measure the incidence and location of sleep-wake transitions during abnormal breathing patterns, as well as their temporal relationship with major ventilatory events.