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Introduction: Breathing changes induced by repeated short olfactory stimuli are used as an objective indicator of the integrity of the olfactory system. Until now, it has not been investigated whether chemosensorically induced changes in inspiratory and expiratory time parameters can be suppressed intentionally. The same applies to breathing changes due to weak CO 2 stimuli., Methodology: 34 healthy adult normosmics were stimulated during relaxed regular nasal breathing using a flow olfactometer with nine differently concentrated H 2 S and three weak CO 2 stimulation pulses. They were instructed to intentionally maintain regular nasal breathing during the stimulation. A significant breathing change was present if the duration of the inspiration (DIN) or the expiration (DEX) of the first stimulatory breath was outside the double standard deviation of the mean of five prestimulatory regular breaths. These could be shortened or extended the DIN or DEX., Results: Despite high motivation, the chemosensorically induced breathing changes could not be suppressed intentionally. Rest breathing reacted to both stimulants by changes in both the inspiratory and the expiratory time parameters. However, it outweighed the expiratory reactions. CO 2 evoked more breathing changes than H 2 S. The frequency of reaction rate of H 2 S stimuli was not concentration-dependent. Strong H 2 S stimuli induced more frequent shortening than prolongation of DEX., Conclusions: Chemosensorically triggered breathing changes cannot be suppressed intentionally. They therefore provide an additional objective tool to check the functionality of nasal chemosensory afferents., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Background: In a previous study, the detection threshold for H2S during aerobic exercise worsened with forced nasal breathing. The cause remained unclear. It is to be examined how the detection threshold changes with exclusive mouth breathing., Material and Methods: During a resting phase, an aerobic physical load and subsequent recovery phase, different H2S concentrations were applied inspiratory-synchronously intranasal using a flow-olfactometer in a staircase procedure. The missing nasal breathing was objectified online and offline. The reaction times were determined. In parallel, various vital parameters have been measured., Results: The passive detection thresholds for H2S between the load and recovery phases did not differ. In the resting phase, the threshold was highest. The reaction times were not different in the three experimental phases., Conclusion: An increased sympathetic tone, resulting from an approximately half-hour aerobic exercise, did not change the passive olfactory threshold for H2S during oral respiration compared to the subsequent recovery period. The high olfactory threshold in the resting phase might be explained by initial adaptation difficulties to the experimental conditions., Competing Interests: Die Autoren geben an, dass kein Interessenkonflikt besteht., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background: Sleep-disordered breathing (SDB) represents a common and highly relevant co-morbidity in patients with atrial fibrillation (Afib). Obstructive sleep apnea (OSA) has been identified as an independent risk factor for developing Afib and for Afib recurrence after treatment, but the role of central sleep apnea (CSA) is less clear. This study investigated characteristics of SDB in Afib patients with preserved left ventricular ejection fraction (PEF)., Methods and Results: Consecutive patients (07/2007 to 03/2016) with documented Afib at hospital admission and PEF undergoing 6-channel cardiorespiratory polygraphy (PG) screening were retrospectively analyzed. A total of 211 patients were included (146 men; age 68.7 ± 8.5 years). Only 6.6% of patients had no SDB (apnea-hypopnea index [AHI] < 5/h). When moderate-to-severe SDB (AHI ≥ 15/h) was classified based on the predominant type of apneas and hypopneas, OSA (≥ 80% obstructive events) was found in 15% of patients, CSA (≥ 80% central events) in 10%, and 36% had mixed sleep apnea. For patients with Cheyne-Stokes respiration (CSR; 34%), time spent in CSR increased significantly as total AHI increased (p < 0.001); total CSR duration was 20, 50, and 117 min, respectively, in patients with mild, moderate, and severe SDB., Conclusions: SDB was highly prevalent in this cohort of patients with Afib and PEF. The proportion of patients with moderate-to-severe OSA, for whom treatment is recommended by current guidelines, was about 15%. With 36% of patients presenting with moderate-to-severe mixed sleep apnea and almost 10% of patients having CSA, treatment guidelines for these types of SDB in the setting of Afib are needed.

Introduction: Alterations of breathing pattern evoked by odors are used to proof the integrity of the olfactory system in the sense of respiratory olfactometry. Spontaneous breathing changes normally cannot be distinguished from evoked changes. It is therefore necessary to repeatedly apply stimuli with a pure odorant during tidal breathing, randomized with neutral air, to detect a majority of olfactory-evoked respiratory changes., Methods: In 26 adult normosmics, 15 H 2 S and 15 neutral air stimuli (duration: 2 sec) were randomly applied with an interstimulus interval of at least 1 minute, using a flow olfactometer. Before stimulation, the respiration was not allowed to scatter significantly (variation coefficient of the duration of inspiration (DIN) and expiration (DEX) ≤0.1). A respiratory response was fulfilled when respectively DIN and DEX of the stimulus breath exceeded the double standard deviation of the same parameters in the five preceding respiratory cycles. The number of reactions was normalized to the number of stimuli and to the off-line as regularly calculated respiratory complexes and thus reaction indices were formed., Results: H 2 S stimuli clearly evoked more respiratory changes than neutral air stimuli. DIN and DEX decreased with olfactory stimulation more frequently than with an application of neutral air. Extensions of DIN and DEX were not different between the two stimulus qualities., Conclusions: Only the randomized nasal stimulation with an odor and a blank makes the respiration-olfactometry meaningful., Competing Interests: Interessenkonflikt: Die Autoren geben an, dass kein Interessenkonflikt besteht., (Georg Thieme Verlag KG Stuttgart · New York.)

Sleep disordered breathing (SDB) (obstructive sleep apnea, central sleep apnea/Cheyne-Stokes respiration or the combination of both) is highly prevalent in patients with a wide variety of cardiovascular diseases including hypertension, arrhythmia, coronary artery disease, myocardial infarction and stroke (reviewed previously in the September issue of this journal). Its close association with outcomes in chronic heart failure with reduced ejection fraction (HF-REF) suggests that it may be a potential treatment target. Herein, we provide an update on SDB and its treatment in HF-REF.

Background: The affective valence of an olfactory stimulus will be encoded in its respiratory response. Unpleasant odors shorten the inhalation of the first stimulated breaths in wakefulness and sleep. The aim of the present study was to assess the effekt of intravenous anesthetic propofol on the chemosensory evoked changes of breathing pattern., Material and Methods: 13 ASA 1/2 patients got intranasal chemosensory stimuli (H2S and CO2) by flow-olfactometer during "deep" (EEG-based bispectral analysis, BIS:≤60) and "moderate" (BIS>60) propofol-induced sedation with preserved spontaneous breathing. The duration of the in- and exhalation was analyzed for 5 breaths before and for 2 breaths after the onset of stimulation., Results: During deep sedation respiratory reactions were observed only by CO2 irritation. During moderate sedation respiratory responses were evoked by H2S stimuli, too. In moderate sedation extensions of the inhalations of the first breath after both the unpleasant pure olfactory H2S stimuli and the trigeminal stimuli were more frequent than reductions., Conclusion: Olfactory stimuli change the breathing only during moderate sedation, trigeminal stimuli during deep and moderate propofol-induced sedation. In opposite to both wakefulness and sleep the duration of inhalation is often extended by H2S-stimuli during moderate sedation., (© Georg Thieme Verlag KG Stuttgart · New York.)

Aims: Sleep-disordered breathing (SDB), in particular obstructive sleep apnoea, is associated with an increased risk of onset or recurrence of atrial fibrillation (AF) and atrial flutter. This prospective study investigated the relationship between restoration of sinus rhythm and SDB in patients with AF or atrial flutter., Methods and Results: 138 consecutive patients (age 67.8 ± 10.3 years, 67.4 % male) with AF (86.2 %) or atrial flutter (13.8 %) were enrolled and underwent multichannel cardiorespiratory polygraphy the night before and immediately after electrical cardioversion (CV). None of the patients was treated with ventilation therapy before or during the study. Overall prevalence of SDB [apnoea-hypopnoea index (AHI) ≥5/h] was 92 % and prevalence of moderate-to-severe SDB (AHI) ≥15/h was 64 %. Within the first night after CV, AHI decreased from 23.4 ± 16.3 to 16.3 ± 11.5/h, p < 0.001. This was due to a significant decrease in central respiratory events, with a total reduction of patients showing central sleep apnoea (n = 53 at baseline vs n = 23 immediately after CV; p < 0.001)., Conclusions: In conclusion, SDB represents a highly prevalent comorbidity in patients with atrial arrhythmias. Through cardioversion, an immediate reduction of SDB can be detected due to a significant reduction in central respiratory events.

Obstructive sleep apnoea and central sleep apnoea/Cheyne-Stokes respiration are collectively referred to as sleep-disordered breathing (SDB). Rapidly accumulating evidence suggests that both forms of SDB, and often a combination of both, are highly prevalent in patients with a wide variety of cardiovascular diseases, including hypertension, heart failure, arrhythmias, coronary artery disease, acute coronary syndrome and stroke. The presence of SDB in these patients is independently associated with worse cardiac function and exercise tolerance, recurrent arrhythmias, infarct expansion, decreased quality of life and increased mortality. Recent data suggest positive effects of positive airway pressure (PAP) therapy on quality of life and cardiovascular function. In addition, ongoing clinical trials may soon provide first definitive data on PAP therapy of SDB on hard outcomes such as mortality. This review presents current data highlighting links between SDB and a variety of cardiovascular conditions, the importance of recognising and diagnosing SDB in patients with cardiovascular disease, and the effects of effective SDB treatment on cardiovascular endpoints.

Background: A prestimulatory regular breathing is required for the respiration-olfactometry. In a sitting position, just about every second prestimulatory breathing sequence fulfilled this requirement checking off -line. It should be examined whether breathing in reclining position is more regular., Methods: The coefficients of variation of the time parameters of breathing in reclining and sitting position during 30 min were determined and compared., Results: Breathing regularity did not increase in reclining position with 48 healthy persons (age group 1: 18 to 30 years, n = 24, 18 women; age group 2: > 55 years, n = 24, 13 women). The age and gender had no eff ect on the proportion of regular breathing. With 7 persons, the yield of 5 on each other following regular breaths was inadequate. Additionally one person excluded from our study was not able to breathe regularly without interruptions., Conclusion: The respiration-olfactometry cannot be performed in each person. It is not more successful in reclining than in sitting position., (© Georg Thieme Verlag KG Stuttgart · New York.)

This study investigated the effect of heart failure on respiratory patterns in patients with obstructive sleep apnoea (OSA). 39 patients with established OSA (apnoea/hypopnoea index (AHI) >10 events·h(-1)) and either with heart failure (New York Heart Association (NYHA) class II and III, left ventricular-ejection fraction (LVEF) ≤40%; n=26, age mean ± SD 67 ± 9 years) or without heart failure (LVEF ≥50%, N-terminal pro-brain naturic peptide <400 pg·mL(-1); n=13, age 73 ± 6 years) underwent simultaneous right- and left-heart catheterisation within 12 h of cardiorespiratory polygraphy recording. Respiratory patterns of OSA were significantly longer in OSA patients with heart failure versus without heart failure, including mean ± SD cycle length (46.0 ± 10.0 versus 37.8 ± 10.6 s; p=0.024), ventilation length (25.4 ± 6.3 versus 21.3 ± 7.1 s; p=0.044), apnoea length (20.5 ± 4.9 versus 16.5 ± 3.9 s; p=0.013), time-to-peak ventilation (10.6 ± 3.0 versus 8.3 ± 2.5 sc; p=0.021) and circulatory delay (28.5 ± 7.5 versus 22.6 ± 3.7 s; p=0.005). Positive and robust correlations were found between some of these parameters and the degree of congestion in heart failure: cycle length (r=0.53; p=0.006), ventilation length (r=0.55; p=0.004) and time-to-peak ventilation (r=0.47; p=0.015) all increased with a rise in pulmonary capillary wedge pressure. Respiratory patterns in OSA appear to be dependent on cardiac function, with an increase in event lengths as cardiac function decreases. In patients with heart failure, some of these events correlate with the degree of pulmonary congestion.

Sleep disordered breathing is of major prognostic relevance in heart failure patients. With increasing severity of heart failure, prevalence of Cheyne-Stokes respiration (CSR) rises. Due to pathophysiological interactions Cheyne-Stokes respiration and heart failure may lead to a vicious circle. Therefore therapeutic approaches are necessary. Because CSR can markedly improve with recovery of cardiac function, Guideline driven heart failure treatment represents the foundation of an adequate therapy of CSR in heart failure patients. This includes maximum medical treatment, optimal myocardial revascularisation and, if guidelines recommend cardiac resynchronization therapy. In case CSR persists specific therapy seems to be appropriate. Recently, adaptive servoventilation was introduced as the most favourable ventilation therapy in these patients. Beside tremendous effects on CSR improvement of cardiac functional parameters in heart failure patients has been shown. Nevertheless randomised, controlled studies are awaited to assess its value in heart failure therapy. [ABSTRACT FROM AUTHOR]