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Resume L’hypoxie hypobare, caracteristique de l’environnement d’altitude, a des consequences physiologiques importantes sur les systemes cardio-vasculaire et respiratoire, qui sont fortement stimules pour maintenir au mieux un apport en oxygene le plus adequat possible. Ce processus dynamique d’acclimatation est influence a la fois par le niveau d’altitude concerne et la vitesse de progression mais est aussi tres individuel avec des reponses et des sensibilites variables. Ce large spectre des reponses est aussi a l’origine de symptomes plus ou moins importants caracterisant des pathologies specifiques que sont le mal aigu des montagnes, l’œdeme cerebral et l’œdeme pulmonaire de haute altitude. Cet article se propose de faire le point sur les connaissances actuelles a la fois sur l’acclimatation mais aussi sur les differentes pathologies specifiques a l’hypoxie d’altitude.

Resume Introduction L’insuffisance cardiaque touche pres de 2 % de la population avec une morbi-mortalite elevee malgre les avancees de la prise en charge therapeutique. Le syndrome d’apnee du sommeil (SAS) constitue un facteur de risque et d’aggravation de la dysfonction myocardique. Etat des connaissances Le SAS est retrouve chez 70 % des patients insuffisants cardiaques, 65 % des patients avec hypertension arterielle refractaire, 60 % des patients avec accident vasculaire cerebral et 50 % des patients avec fibrillation atriale. La morbidite cardiovasculaire associee est multipliee par 2 a 3. Les mecanismes physiopathologiques sont l’hypoxie intermittente nocturne, les variations de capnie, les variations de pressions intrathoraciques et les micro-eveils repetes, le tout concourant en une hyperactivation sympathique, une dysfonction endotheliale et une inflammation systemique. Conclusions La prise en charge du SAS chez les patients presentant une dysfonction myocardique doit etre couplee a la prise en charge cardiologique. Il est necessaire de poursuivre les evaluations scientifiques afin de determiner un parcours de soins precis et la place respective de chacune des prises en charge pneumologique et cardiologique.

Is the stress test still part of the useful examinations in the detection of risk heart disease in sports subjects? Should we continue to use it as a surveillance examination in coronary sports patients? Meta-analysis, considering a ST subshift of more than 1mm as a criterion for positivity, underline the low prevalence of abnormal examinations and a significant rate of false-positives. But for the diagnosis of coronary artery disease, it is mainly the evolution of the ST segment to effort or recovery and the occurrence of stress arrhythmias that detect true positivity. When coronary risk is more important (presence of risk factors, resumption of sport, intense and prolonged efforts), it seems lawful to recommend such a review on a regular basis among men over 40 years of age with two risk factors but Also among veterans taking up sport after a period of prolonged inactivity. For the asymptomatic coronary athlete the stress test remains at the centre of the final decision for the resumption of a sport in competition irrespective of the method of revascularization. Of course the stress test, even inevitable, remains flawed in the detection of coronary artery disease in the asymptomatic athlete. However, it provides additional information on the condition of being maximal, and attaching importance to arrhythmias, the tensional profile and the maximum power developed in addition to the ST segment's only study.

We measured the effects of adding CO2 to an inhaled hypoxic gas mixture on cardio-respiratory parameters during maximal exercise. Eight young males performed four incremental maximal exercise tests on cycle under ambient air, hypoxia (FIO2 0.125), inhaled CO2 (FICO2 0.045), and combination of hypoxia and inhaled CO2. The highest ventilation (VE) and VE/CO2 output were recorded in CO2 inhalation and combined treatments. Arterial O2 partial pressure was higher in combined than in hypoxia treatment, but the difference between the treatments narrowed from rest to end-exercise, at least partly because the magnitude of the increase in VE (%) at exercise was smaller in combined treatment than in hypoxia. Arterial O2 content was higher in combined treatment than in hypoxia at rest, but no more at maximal exercise. Cardiac output was higher and O2 extraction lower when breathing O2-poor gas mixtures than under the two other treatments. For a given oxygen consumption, hypoxia and combined treatment showed similar cardiac output and O2 extraction.

Background: While millions of people are living permanently at high altitude (>2500m) worldwide, the mechanisms underlying their tolerance to chronic hypoxia and those responsible for the occurrence of chronic mountain sickness (CMS) remain to be elucidated. Excessive erythrocytosis (EE) is thought to be the main mechanism responsible for CMS symptoms and is included in the definition of CMS but the precise interplay between EE and CMS has been poorly described. Methods: The present study benefits from an exceptional dataset coming from 1594 dwellers of La Rinconada, the highest city in the world (5100-5300m). Based on individual clinical characteristics, subjects were categorized according to i) the presence of EE, ii) CMS symptoms severity and iii) CMS diagnosis based on current guidelines. Findings: The prevalence of EE (44%) and CMS diagnosis (26%) was high compared to other highlander populations. Individuals with EE reported few symptoms while symptomatic individuals had lower hematocrit compared to asymptomatic counterparts. Multivariable analysis revealed that age and sex are the main factors associated with EE while age, hematocrit and number of years living at La Rinconada are factors associated with CMS symptoms. Interpretation: High hematocrit values may be required to reside in La Rinconada with limited symptoms. These results might question the classical definition of CMS in such high altitude population. Funding Statement: This work was supported by the ‘‘Fonds de dotation AGIR pour les maladies chroniques’’ and by the French National Research Agency (ANR-12-TECS-0010) in the framework of the ‘‘Investissements d’avenir’’ program (ANR-15-IDEX-02). Declaration of Interests: All authors have no conflict of interest related to the present work to disclose. Ethics Approval Statement: The study was approved by the ethics committees of Inter-region Rhone-Alpes-Auvergne (IRB-5891) and Universidad Nacional Mayor de San Marcos (CIEI-2019-002).

Background Appropriate advice for the practice of sport in patients with a cardiomyopathy is a challenging issue. Recent evolution towards more comprehensive and tailored recommendations may facilitate the clinical practice. However, neither their application in real life has been evaluated nor the concordance within clinicians. Methods We submitted six cases from real life to an expert panel of eighteen clinicians (7 cardiomyopathy experts, 7 arrhythmia experts, 4 sport physicians). The six athletes had Hypertrophic (HCM, n = 3), Dilated (DCM, n = 2), Right ventricular arythmogenic (ARVC, n = 1) cardiomyopathy. Advice for the practice of sport (competitive or recreational, globally or regarding the main usual activity of the athlete or according to detailed sports classification) was collected through a structured questionnaire. Results Experts authorize the practice of the usual sport in 28% of total cases. Global concordance within experts is significant but low (Kendall W = 0.34, P Conclusions Divergent advices were observed between experts regarding sports activity that can be authorized in athletes with a cardiomyopathy. Advices were also frequently discordant with recent European recommendations. These results underline difficulties for athletes’ personalized recommendation and the need for large prospective studies to progress towards optimal management.

Introduction Living in high altitude is challenging for the cardiovascular system, and some of highlanders develop a chronic mountain sickness (CMS). Only few data are available above the altitude of 4380 m. La Rinconada is the highest mining city in the world at an altitude of 5100 m. Objective To describe heart remodeling and pulmonary hemodynamic and study the relationship with CMS. Method Rest and exercise echocardiography were performed in Lima (sea level, n = 18), Puno (3810 m, n = 23) and La Rinconada (n = 55). Results Age and BMI were higher in La Rinconada (30 ± 2; 32 ± 3; 43 ± 2 years and 24 ± 1; 25.4 ± 0.8 and 25.9 ± 0.4 kg.m-2 in Lima, Puno and La Rinconada respectively). Mean arterial pressure were normal and comparable regardless of altitude. As expected, hematocrit significantly (P Fig. 1 ). Conclusion These are the first data of a population living permanently above 5100 m. Eccentric LV remodeling, larger right cavities, lowering myocardial strain in both ventricle are the main findings. The higher rest and exercise TVR in altitude are only related to the hematocrit level.

International audience; Physical performance relies on the concerted action of myriad responses, many of which are under circadian clock control. Little is known, however, regarding the time-dependent effect on exercise performance at the molecular level. We found that both mice and humans exhibit daytime variance in exercise capacity between the early and late part of their active phase. The daytime variance in mice was dependent on exercise intensity and relied on the circadian clock proteins PER1/2. High-throughput gene expression and metabolic profiling of skeletal muscle revealed metabolic pathways that are differently activated upon exercise in a daytime-dependent manner. Remarkably, we discovered that ZMP, an endogenous AMPK activator, is induced by exercise in a time-dependent manner to regulate key steps in glycolytic and fatty acid oxidation pathways and potentially enhance exercise capacity. Overall, we propose that time of day is a major modifier of exercise capacity and associated metabolic pathways.

Objectif Le sous diagnostic du SAOS est responsable d’une morbidite per-operatoire et son aggravation est potentiellement un facteur d’arythmies cardiaques post-operatoires. Etudier l’impact du SAOS sur les evenements cardiaques rythmiques apres chirurgie sous anesthesie generale (AG). Methodes Etude monocentrique cas temoins prospective non randomisee (juin 2015–juillet 2018). Les patients adresses en consultation d’anesthesie pour une chirurgie digestive ou urologique sous AG suivie d’hospitalisation ≥ 2 jours, âges ≥ 40 ans, avec questionnaire STOP-BANG ≥ 3 effectuaient une polygraphie ventilatoire couplee a un holter-ECG, nuit N0 (pre-operatoire) puis a N1 et N3 en post-chirurgie. Le « SAOS » etait defini par un IDO > 10 et/ou un IAH > 15, les patients presentant un IDO > 40/h etaient exclus. Resultats Cent vingt patients avec STOP-BANG ≥ 3 etaient inclus, 62 avec SAOS et 29 non SAOS, 13 patients (11 %) etaient exclus pour SAOS severe et 16 patients (13 %) sortis d’etude. Les anomalies rythmiques associees aux episodes hypoxiques augmentaient significativement en N3 par rapport a N0 sur la population totale (1 [0 ; 4] vs 0 [0 ; 2], p = 0,04), dans le groupe SAOS (1 [0 ; 4] vs 1 [0 ; 2], p = 0,02) mais pas dans le groupe non SAOS (0 [0 ; 5,5] vs 0 [0 ; 2,5], p = 0,84). Il n’existait pas d’aggravation significative de l’IAH et de l’IDO en post-operatoire. Conclusion Les arythmies cardiaques associees aux episodes hypoxiques se majorent lors de la 3e nuit post-operatoire chez les patients SAOS, demontrant la necessite d’un depistage du SAOS en pre-operatoire.

Summary Hepatopulmonary syndrome (HPS) is of prognostic value in patients awaiting for orthotopic liver transplantation (OLT), but little is known about the effect of cirrhotic cardiomyopathy (CCM). The aim of the present study was to estimate the prevalence and possible relation between respiratory and cardiac abnormalities in a same series of patients awaiting OLT. Special attention was paid to the prognostic value of CCM in comparison to HPS. Eighty-three patients were included (19 females, 64 males; 52.1 ± 10.0 yrs). All had lung function testing with arterial blood gases and echocardiographic evaluation at rest with a contrast echocardiography in case of arterial oxygenation defect. To estimate the presence of CCM, patients underwent a complete left and right echocardiography and Doppler examination. Complete echocardiographic assessment could be obtained in 64 of the 83 patients of the study. HPS was observed in 16.9% (14/83) and CCM in 23.4% (15/64) of patients. There was a tendency of more serious adverse events before and after OLT in patients with HPS in comparison to others but CCM was not of prognostic value. HPS and CCM were frequent in these patients awaiting OLT but both abnormalities were not found in the same patients. CCM was neither related to death before OLT nor to death or serious adverse events after OLT.

It was previously shown that dehydroepiandrosterone (DHEA) reverses chronic hypoxia-induced pulmonary hypertension (PH) in rats, but whether DHEA can improve the clinical and hemodynamic status of patients with PH associated to chronic obstructive pulmonary disease (PH-COPD) has not been studied whereas it is a very severe poorly treated disease.Eight patients with PH-COPD were treated with DHEA (200mg daily orally) for 3 months. The primary end-point was the change in the 6-minute walk test (6-MWT) distance. Secondary end-points included pulmonary hemodynamics, lung function tests and tolerance of treatment.The 6-MWT increased in all cases, from 333m (median [IQR]) (257; 378) to 390m (362; 440) (P0.05). Mean pulmonary artery pressure decreased from 26mmHg (25; 27) to 21.5mmHg (20; 25) (P0.05) and pulmonary vascular resistance from 4.2UI (3.5; 4.4) to 2.6UI (2.5; 3.8) (P0.05). The carbon monoxide diffusing capacity of the lung (DLCO % predicted) increased significantly from 27.4% (20.1; 29.3) to 36.4% (14.6; 39.6) (P0.05). DHEA treatment did not change respiratory parameters of gas exchange and the 200mg per day of DHEA used was perfectly tolerated with no side effect reported.DHEA treatment significantly improves 6-MWT distance, pulmonary hemodynamics and DLCO of patients with PH-COPD, without worsening gas exchange, as do other pharmacological treatments of PH (trial registration NCT00581087).

To evaluate the role of central and peripheral contributions to exercise limitation after transplantation, we compared, during exercise, 2 groups of very well-trained heart transplants recipients (HTRs) and kidney transplant recipients (KTRs) with a group of control subjects (CSs), matched for physical level.Nineteen male subjects, 7 HTRs, 6 KTRs and 6 CSs, participated in the study. All transplant patients were in sinus rhythm and were matched for immunosuppressive therapy, none of whom had therapy with chronotropic effects. Exercise capacities were evaluated using a symptom-limited treadmill test. Oxygen consumption (VO2) and heart rate (HR) were measured continuously. Heart rate reserve (HRR) was defined as peak HR minus resting HR; resting HR was the stabilized HR measured in the supine position before the treadmill test.Functional capacities were evaluated for all HTRs, KTRs and CSs, according to maximal VO2 (41.5 +/- 4.0, 52.0 +/- 8.7 and 50.6 +/- 9.0 ml/kg per min, respectively), maximal treadmill speed (9.9 +/- 1.2, 12.7 +/- 1.9 and 15.5 +/- 1.5 km/h) and HRR (65 +/- 17, 101 +/- 12 and 110 +/- 11 beats per minute [bpm]), which were significantly lower in the HTR group (p0.05). Regardless of type of organ transplant, both HTR and KTR patients had a similar VO2/treadmill speed relationship, significantly higher than in the CS group. HRR correlated with maximal VO2 for HTRs (r = 0.72, p0.05).Despite regular training, the decreased mechanical efficiency reflected by an increased VO2/treadmill speed relationship suggests a peripheral limitation in both heart and kidney transplant patients. Furthermore, exercise limitations in HTRs likely arose from both central and peripheral factors, in view of their specific HRR reduction. These factors probably contributed to the decreased speed and VO2 observed in the HTR group.

Objectives : Circulating adrenomedullin (ADM), a potent vasorelaxing and natriuretic peptide involved in cardiovascular homeostasis, is increased after cardiac and renal transplantation. ADM is also implicated in hemodynamic abnormalities during liver cirrhosis, but whether ADM is increased late after liver transplantation is unknown. Patients : A total of 18 subjects—10 liver-transplant patients (Ltx) and 8 healthy subjects—were enrolled in the study. Design and measurements : After a 15-min rest period in supine position, heart rate and systemic blood pressure were determined in all subjects. Then, venous blood samples were obtained in order to simultaneously determine the cyclosporine through levels, the biological (cyclosporine, renal and hepatic functions) and hormonal (ADM and atrial natriuretic peptide (ANP)) characteristics of the Ltx. Results : ADM (27.2±4.1 vs. 53.8±6.9 pmol/l, P =0.02), and ANP (5.9±0.9 vs. 12.8±1.4 pmol/l, P =0.001) were significantly increased in late, stable Ltx (35.4±9.6 months after transplantation). Furthermore, increased ADM correlated positively with elevated creatinine ( r =0.76, P =0.01) and ANP ( r =0.64, P =0.04) after liver transplantation. Conclusions : Liver-transplant patients exhibit a sustained increase in circulating ADM. Such an increase likely results from renal impairment associated with volume regulation abnormalities, suggesting a potential role for ADM in volume regulation after liver transplantation.