Christoph Langer

Bio: Christoph Langer is an academic researcher from University of Kiel. The author has contributed to research in topics: Heart failure & Cheyne–Stokes respiration. The author has an hindex of 17, co-authored 61 publications receiving 1515 citations. Previous affiliations of Christoph Langer include Heart and Diabetes Center North Rhine-Westphalia & Ruhr University Bochum.

Sleep-disordered breathing in heart failure with normal left ventricular ejection fraction.

Abstract: Aims In patients with systolic heart failure (SHF) a high prevalence of sleep-disordered breathing (SDB) has been documented. The purpose of this study was to investigate the prevalence and type of SDB in patients with heart failure with normal left ventricular ejection fraction (HFNEF). Methods and results Two hundred and forty-four consecutive patients (87 women, aged 65.3 ± 1.4 years) with HFNEF underwent capillary blood gas analysis, measurement of NT-proBNP concentrations, echocardiography, cardiopulmonary exercise testing (CPX), cardiorespiratory polygraphy, and simultaneous right and left heart catheterization. Sleep-disordered breathing was defined as an apnoea–hypopnoea-index (AHI) ≥5/h. Sleep-disordered breathing was documented in 69.3% of all patients, 97 patients (39.8%) presented with OSA and 72 patients (29.5%) with CSA. With an increasing impairment of diastolic function the proportion of SDB, and CSA in particular, increased. Patients with SDB performed worse on CPX and six-minute walk test. Partial pressure of CO2 was lower in CSA, whereas AHI, left atrial diameter, NT-proBNP, LVEDP, PAP, and PCWP were higher. Conclusion There is a high prevalence of SDB in HFNEF. In parallel to SHF, CSA patients in particular are characterized by a more impaired cardiopulmonary function. Whether SDB is of prognostic relevance in HFNEF needs to be determined.

Cheyne-Stokes respiration and obstructive sleep apnoea are independent risk factors for malignant ventricular arrhythmias requiring appropriate cardioverter-defibrillator therapies in patients with congestive heart failure.

Abstract: Aims The aim of this first large-scale long-term study was to investigate whether obstructive sleep apnoea (OSA) and/or central sleep apnoea (CSA) are associated with an increased risk of malignant cardiac arrhythmias in patients with congestive heart failure (CHF). Methods and results Of 472 CHF patients who were screened for sleep disordered breathing (SDB) 6 months after implantation of a cardiac resynchronization device with cardioverter-defibrillator, 283 remained untreated [170 with mild or no sleep disordered breathing (mnSDB) and 113 patients declined ventilation therapy] and were included into this study. During follow-up (48 months), data on appropriately monitored ventricular arrhythmias as well as appropriate cardioverter-defibrillator therapies were obtained from 255 of these patients (90.1%). Time period to first monitored ventricular arrhythmias and to first appropriate cardioverter-defibrillator therapy were significantly shorter in patients with either CSA or OSA. Forward stepwise Cox models revealed an independent correlation for CSA and OSA regarding monitored ventricular arrhythmias [apnoea–hypopnoea index (AHI) ≥5 h−1: CSA HR 2.15, 95% CI 1.40–3.30, P < 0.001; OSA HR 1.69, 95% CI 1.64–1.75, P = 0.001; AHI ≥15 h−1: CSA HR 2.06, 95% CI 1.40–3.05, P < 0.001; OSA HR 1.69, 95% CI 1.14–2.51, P = 0.02] and appropriate cardioverter-defibrillator therapies (AHI ≥5 h−1: CSA HR 3.24, 95% CI 1.86–5.64, P < 0.001; OSA HR 2.07, 95% CI 1.14–3.77, P = 0.02; AHI ≥15 h−1: CSA HR 3.41, 95% CI 2.10–5.54, P < 0.001; OSA HR 2.10, 95% CI 1.17–3.78, P = 0.01). Conclusion In patients with CHF, CSA and OSA are independently associated with an increased risk for ventricular arrhythmias and appropriate cardioverter-defibrillator therapies.

Adaptive servoventilation improves cardiac function in patients with chronic heart failure and Cheyne–Stokes respiration

Abstract: Background and aims Sleep disordered breathing (SDB), especially Cheyne–Stokes respiration (CSR) is common in patients with chronic heart failure (CHF). Adaptive servoventilation (ASV) was recently introduced to treat CSR in CHF. The aim of this study was to investigate the effects of ASV on CSR and CHF parameters. Methods In 29 male patients (63.9±9 years, NYHA≥II, left ventricular ejection fraction [LV-EF]≤40%), cardiorespiratory polygraphy, cardiopulmonary exercise (CPX) testing, and echocardiography were performed and concentrations of NT-proBNP determined before and after 5.8±3.5 months (median 5.7 months) of ASV (AutoSet CS™2, ResMed) treatment. All patients also received guideline-driven CHF therapy. Results Apnoea–hypopnoea-index was reduced from 37.4±9.4/h to 3.9±4.1/h (p<0.001). Workload during CPX testing increased from 81±26 to 100±31 W (p=0.005), oxygen uptake (VO2) at the anaerobic threshold from 12.6±3 to 15.3±4 ml/kg/min (p=0.01) and predicted peak VO2 from 58±12% to 69±17% (p=0.007). LV-EF increased from 28.2±7% to 35.2±11% (p=0.001), and NT-proBNP levels decreased significantly (2285±2192 pg/ml to 1061±1293 pg/ml, p=0.01). Conclusions In selected patients with CHF and CSR, addition of ASV to standard heart failure therapy is able to improve SDB, CPX test results, LV-EF and NT-proBNP concentrations.

Scanning electron microscopic analysis of different drug eluting stents after failed implantation: From nearly undamaged to major damaged polymers†

Abstract: Background: Implantation of drug eluting stents (DES) in tortuous and/or calcified vessels is much more demanding compared with implantation of bare metal stents (BMS) due to their larger diameters. It is unknown whether drug eluting stent coatings get damaged while crossing these lesions. Methods: In 42 patients (34 male, 68.1 ± 10 years) with 45 calcified lesions (15.9 mm ± 7.9 mm), DES could not be implanted, even after predilatation. Diabetes was present in 19 patients (45 %). Sixty-one stents were used; 19 Cypher select™, 18 Taxus Liberte™, 10 CoStar™, 5 Endeavor RX™, 4 Xience V™. 3 Janus Carbostent™, 1 Yukon Choice S™, and 1 Axxion™ DES. The entire accessible surface area of these stents, in either the unexpanded and expanded state, were examined with an environmental scanning electron microscope (XL30 ESEM, Philips) to evaluate polymer or surface damage. Results: The polymers of Taxus Liberte, Cypher Select, Xience V, CoStar, and Janus DES were only slightly damaged (less than 3% of surface area), whereas the Endeavor RX Stents showed up to 20% damaged surface area. In DES without a polymer (Yukon and Axxion), it could be shown that most of the stent surface (up to 40%) were without any layer of drug. Conclusion: Placement of drug eluting stents in tortuous vessels and/or calcified lesions could cause major surface damage by scratching and scraping of the polymer or drug by the arterial wall, even before implantation. There were remarkable differences among the stents examined, only minor damage with the Cypher, Taxus Costar, Janus, and Xience V, whereas the Endeavor, the Yukon, and the Janus DES showed large areas of surface injury. © 2009 Wiley-Liss, Inc.

Adaptive servoventilation in diastolic heart failure and Cheyne–Stokes respiration

Abstract: A high prevalence of nocturnal Cheyne–Stokes respiration (CSR) has been documented in patients with heart failure with normal left ventricular ejection fraction (HFNEF). The aim of the present study was to investigate the effects of adaptive servoventilation (ASV) for treatment of CSR in these patients. In 60 patients with HFNEF, defined according to current European Society of Cardiology guidelines, CSR was documented by polysomnography (apnoea/hypopnoea index (AHI) of >15 events·h−1). ASV treatment was offered to all patients; 21 initially rejected treatment, withdrew from treatment or presented noncompliant during follow-up (controls), whereas ongoing ASV therapy was initiated in 39 patients (ASV group). Echocardiography, cardiopulmonary exercise testing and measurement of N-terminal-pro-brain natriuretic peptide were performed at baseline and follow-up (11.6±3 months). ASV therapy led to a significant reduction in AHI, longest apnoea and hypopnoea length, maximum and mean oxygen desaturation by pulse oximetry, percentage of study time with an oxygen saturation of <90% and arousal index. In addition, significant positive effects could be confirmed on absolute and predicted peak oxygen consumption, oxygen consumption at the individual aerobic–anaerobic threshold, oxygen pulse, as well as left atrial size, and transmitral flow patterns (mean early diastolic lengthening velocity and the ratio of peak early Doppler mitral inflow velocity to this lengthening velocity). ASV effectively attenuates CSR in patients with HFNEF and improves heart failure symptoms and cardiac function. Whether or not this is accompanied by an improved prognosis remains to be determined.

Rules for Scoring Respiratory Events in Sleep: Update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events

Abstract: The American Academy of Sleep Medicine (AASM) Sleep Apnea Definitions Task Force reviewed the current rules for scoring respiratory events in the 2007 AASM Manual for the Scoring and Sleep and Associated Events to determine if revision was indicated. The goals of the task force were (1) to clarify and simplify the current scoring rules, (2) to review evidence for new monitoring technologies relevant to the scoring rules, and (3) to strive for greater concordance between adult and pediatric rules. The task force reviewed the evidence cited by the AASM systematic review of the reliability and validity of scoring respiratory events published in 2007 and relevant studies that have appeared in the literature since that publication. Given the limitations of the published evidence, a consensus process was used to formulate the majority of the task force recommendations concerning revisions.The task force made recommendations concerning recommended and alternative sensors for the detection of apnea and hypopnea to be used during diagnostic and positive airway pressure (PAP) titration polysomnography. An alternative sensor is used if the recommended sensor fails or the signal is inaccurate. The PAP device flow signal is the recommended sensor for the detection of apnea, hypopnea, and respiratory effort related arousals (RERAs) during PAP titration studies. Appropriate filter settings for recording (display) of the nasal pressure signal to facilitate visualization of inspiratory flattening are also specified. The respiratory inductance plethysmography (RIP) signals to be used as alternative sensors for apnea and hypopnea detection are specified. The task force reached consensus on use of the same sensors for adult and pediatric patients except for the following: (1) the end-tidal PCO(2) signal can be used as an alternative sensor for apnea detection in children only, and (2) polyvinylidene fluoride (PVDF) belts can be used to monitor respiratory effort (thoracoabdominal belts) and as an alternative sensor for detection of apnea and hypopnea (PVDFsum) only in adults.The task force recommends the following changes to the 2007 respiratory scoring rules. Apnea in adults is scored when there is a drop in the peak signal excursion by ≥ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study), or an alternative apnea sensor, for ≥ 10 seconds. Hypopnea in adults is scored when the peak signal excursions drop by ≥ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative sensor, for ≥ 10 seconds in association with either ≥ 3% arterial oxygen desaturation or an arousal. Scoring a hypopnea as either obstructive or central is now listed as optional, and the recommended scoring rules are presented. In children an apnea is scored when peak signal excursions drop by ≥ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study), or an alternative sensor; and the event meets duration and respiratory effort criteria for an obstructive, mixed, or central apnea. A central apnea is scored in children when the event meets criteria for an apnea, there is an absence of inspiratory effort throughout the event, and at least one of the following is met: (1) the event is ≥ 20 seconds in duration, (2) the event is associated with an arousal or ≥ 3% oxygen desaturation, (3) (infants under 1 year of age only) the event is associated with a decrease in heart rate to less than 50 beats per minute for at least 5 seconds or less than 60 beats per minute for 15 seconds. A hypopnea is scored in children when the peak signal excursions drop is ≥ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative sensor, for ≥ the duration of 2 breaths in association with either ≥ 3% oxygen desaturation or an arousal. In children and adults, surrogates of the arterial PCO(2) are the end-tidal PCO(2) or transcutaneous PCO(2) (diagnostic study) or transcutaneous PCO(2) (titration study). For adults, sleep hypoventilation is scored when the arterial PCO(2) (or surrogate) is > 55 mm Hg for ≥ 10 minutes or there is an increase in the arterial PCO(2) (or surrogate) ≥ 10 mm Hg (in comparison to an awake supine value) to a value exceeding 50 mm Hg for ≥ 10 minutes. For pediatric patients hypoventilation is scored when the arterial PCO(2) (or surrogate) is > 50 mm Hg for > 25% of total sleep time. In adults Cheyne-Stokes breathing is scored when both of the following are met: (1) there are episodes of ≥ 3 consecutive central apneas and/or central hypopneas separated by a crescendo and decrescendo change in breathing amplitude with a cycle length of at least 40 seconds (typically 45 to 90 seconds), and (2) there are five or more central apneas and/or central hypopneas per hour associated with the crescendo/decrescendo breathing pattern recorded over a minimum of 2 hours of monitoring.

2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC)

Abstract: ACC : American College of Cardiology ACE : angiotensin-converting enzyme ACS : acute coronary syndrome AF : atrial fibrillation AGNES : Arrhythmia Genetics in the Netherlands AHA : American Heart Association AMIOVIRT : AMIOdarone Versus Implantable cardioverter-defibrillator:

2015 ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death.

Abstract: 2015 ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC)Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC).

Abstract: ACC : American College of Cardiology ACE : angiotensin-converting enzyme ACS : acute coronary syndrome AF : atrial fibrillation AGNES : Arrhythmia Genetics in the Netherlands AHA : American Heart Association AMIOVIRT : AMIOdarone Versus Implantable cardioverter-defibrillator:

The Expanded Biology of Serotonin

Abstract: Serotonin is perhaps best known as a neurotransmitter that modulates neural activity and a wide range of neuropsychological processes, and drugs that target serotonin receptors are used widely in psychiatry and neurology. However, most serotonin is found outside the central nervous system, and virtually all of the 15 serotonin receptors are expressed outside as well as within the brain. Serotonin regulates numerous biological processes including cardiovascular function, bowel motility, ejaculatory latency, and bladder control. Additionally, new work suggests that serotonin may regulate some processes, including platelet aggregation, by receptor-independent, transglutaminase-dependent covalent linkage to cellular proteins. We review this new “expanded serotonin biology” and discuss how drugs targeting specific serotonin receptors are beginning to help treat a wide range of diseases.