[Factors associated with intrahospital mortality in older patients with COVID-19 in Belgium : The COVID-AgeBru study]. / Face à la COVID-19. Mortalité intra-hospitalière chez les patients âgés de plus de 70 ans avec COVID-19 dans un hôpital universitaire en Belgique :l'étude COVID-AgeBru.

OBJECTIVE: We aimed at assessing the association between demographical and clinical data and the intrahospital mortality in older patients with COVID-19 in Belgium. METHODS: Descriptive, retrospective study of consecutive patients admitted to Brugmann university hospital, Brussels (Belgium) due to COVID-19 (Mars-September-2020). INCLUSION CRITERIA: Patients aged ≥ 70 years admitted to acute care with a positive PCR-RT test, or a highly indicative computed tomography scan. EXCLUSION CRITERIA: Patients transferred to another institution during hospitalization. OUTCOME MEASURE: All-cause intrahospital mortality. Demographic, clinical data, presence of comordibidties and comprehensive geriatric assessment were collected. Adjusted and unadjusted logistic regression were performed. RESULTS: From the 226 eligible patients, 160 (82.7 ± 6.5-year-old; 57.5 % females) met inclusion criteria, from which 67 (42 %) died during hospital stay. The adjusted logistic regression showed an association between intrahospital mortality and increasing age [OR = 1.09 per every year increase (95 % CI 1.02-1.16); p <0.001], type 2 diabetes [OR = 2.75 ( 1.17-6.46); p = 0.021], and acute respiratory distress syndrome (ARDS) [OR = 8.67 ( 3.48-21.61); p < 0.01]. CONCLUSIONS: A higher positive association between intrahospital mortality and increasing age, type 2 diabetes, and ARDS was found. The prognosis value of the comprehensive geriatric assessment in older people with COVID-19 in Belgium requires further studies.

INTRODUCTION: Les études sur l'impact de la pandémie en Belgique sont rares. L'objectif est d'évaluer l'association de l'âge et des comorbidités à la mortalité intra-hospitalière de toutes causes chez les patients âgés ? 70 ans avec COVID-19 dans un hôpital universitaire à Bruxelles, Belgique. Méthodes : Etude rétrospective descriptive des patients admis au CHU Brugmann pour cause de maladie COVID-19 (mars-septembre 2020). Critères d'inclusion : âge ≥ 70 ans admis avec PCR-RT positif ou haute probabilité d'infection au CT-scan thoracique. Critères d'exclusion : transfert dans un autre hôpital. Critère de jugement : toute cause de mortalité intra-hospitalière. Variables collectées : démographiques, cliniques et gériatriques [Katz, Lawton, MMSE, MNA, MNA-SF]. Une régression logistique non ajustée et ajustée a été réalisée. Résultats : Parmi les 226 patients éligibles, 160 (82,7 ± 6,5 ans; 57,5 % femmes) ont rempli les critères d'inclusion. Au total, 67 (42 %) sont décédés durant l'hospitalisation. La régression logistique a montré une association augmentée entre la mortalité et l'âge [odds ratio ou OR = 1,09/année en plus (IC 95 % 1,02-1,16) ; p< 0,001], le diabète de type 2 [OR = 2,75 (1,17-6,46); p = 0,021], l'ARDS [OR = 8,67 (3,48-21,61); p < 0,01]. CONCLUSION: L'âge, le diabète de type 2 et le syndrome de détresse respiratoire aiguë (ARDS) sont associés à une augmentation de la mortalité chez les patients âgés hospitalisés avec COVID-19 en Belgique.

Photonic emitter manipulation to sample nanoscale topography.

We demonstrate that photonic emitter manipulation can be used to image the nanoscale topography of a fluorescently labeled layer in confocal imaging. We exploit the fact that a metallic probe manipulates a fluorophore's photonic environment, and thereby its fluorescent lifetime, in a strongly distance-dependent manner. To image surface topography, a metallic probe that is not in contact with the surface is rasterscanned over a fluorescently labeled sample. The axial position of the probe is kept constant. At each lateral probe position, the fluorescence decay is recorded and analyzed to obtain probe - sample distances and hence, the topography of the sample. We present images resolving a microfabricated step of 14 nm in topography, with the probe positioned at different axial positions.

Dietary energy density in young children across Europe.

OBJECTIVES: To describe energy density (ED; kcal g(-1)) of dietary intake of European children. METHODS: From 16, 228 children who participated in the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) baseline examination, 8551 children with 24-h dietary recalls (24-HDR), with plausible reported energy intakes and complete covariate information were included in the present analysis. ED was calculated using two methods: (1) ED including solid foods (EDF) and (2) ED including solid foods and energy-containing beverages (EDF&B). Beverage energy was calculated in kcal per day. Dietary characteristics and body mass index (BMI) z-score of children aged 2 to <6 years and 6 to <10 years were compared between children with an overall EDF below the <25th percentile, between the 25th and 75th percentile as well as above the >75th percentile. Standardised regression coefficients were estimated to assess the association between dietary characteristics, BMI z-score and ED of the diet. RESULTS: Children with low EDF and EDF&B diets consumed less energy but higher quantity of food and beverages than children with high EDF and EDF&B diets. Consumption of caloric beverages decreased with increasing EDF&B of the diet owing to the relatively low ED of the beverages, in relation to solid foods. Generally, children with low EDF and EDF&B diets showed healthier food choices than peers with higher EDF and EDF&B diets. In this sample, EDF and EDF&B were not associated with BMI z-score. CONCLUSION: Health promotion strategies should proclaim lower ED diets by means of foods with high water and low fat content and mainly fruit and vegetable components. Excluding caloric beverages from EDF calculation is a useful method to avoid misinterpretation of true exposure to a high energy dense diet. We recommend excluding caloric beverages from EDF calculation when investigating the effect of ED on a certain (health) outcome.

Percentile reference values for anthropometric body composition indices in European children from the IDEFICS study.

INTRODUCTION: To characterise the nutritional status in children with obesity or wasting conditions, European anthropometric reference values for body composition measures beyond the body mass index (BMI) are needed. Differentiated assessment of body composition in children has long been hampered by the lack of appropriate references. OBJECTIVES: The aim of our study is to provide percentiles for body composition indices in normal weight European children, based on the IDEFICS cohort (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS). METHODS: Overall 18,745 2.0-10.9-year-old children from eight countries participated in the study. Children classified as overweight/obese or underweight according to IOTF (N=5915) were excluded from the analysis. Anthropometric measurements (BMI (N=12 830); triceps, subscapular, fat mass and fat mass index (N=11,845-11,901); biceps, suprailiac skinfolds, sum of skinfolds calculated from skinfold thicknesses (N=8129-8205), neck circumference (N=12,241); waist circumference and waist-to-height ratio (N=12,381)) were analysed stratified by sex and smoothed 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentile curves were calculated using GAMLSS. RESULTS: Percentile values of the most important anthropometric measures related to the degree of adiposity are depicted for European girls and boys. Age- and sex-specific differences were investigated for all measures. As an example, the 50th and 99th percentile values of waist circumference ranged from 50.7-59.2 cm and from 51.3-58.7 cm in 4.5- to <5.0-year-old girls and boys, respectively, to 60.6-74.5 cm in girls and to 59.9-76.7 cm in boys at the age of 10.5-10.9 years. CONCLUSION: The presented percentile curves may aid a differentiated assessment of total and abdominal adiposity in European children.

Comparison of different prognostic scores in estimating short- and long-term mortality in COVID-19 patients above 60 years old in a university hospital in Belgium.

BACKGROUND AND OBJECTIVES: Multiple scoring systems were used for risk stratification in COVID-19 patients. The objective was to determine among 6 scores which performed the best in predicting short-and long-term mortality in hospitalized COVID-19 patients ≥ 60 years. METHODS: An observational, retrospective cohort study conducted between 21/10/2020 and 20/01/2021. 6 scores were calculated (Clinical Frailty Scale (CFS), Charlson Comorbidity Index (CCI), 4C Mortality Score (4CMS), NEWS score (NEWS), quick-SOFA score (qSOFA), and Quick COVID-19 Severity Index (qCSI)). We included unvaccinated hospitalized patients with COVID-19 ≥ 60 years old in Brugmann hospital, detected by PCR and/or suggestive CT thorax images. Old and nosocomial infections, and patients admitted immediately at the intensive care unit were excluded. RESULTS: 199 patients were included, mean age was 76.2 years (60-99). 47.2% were female. 56 patients (28%) died within 1 year after the first day of hospitalization. The 4CMS predicted the best intrahospital, 30 days and 6 months mortality, with area under the ROC curve (AUROC) 0.695 (0.58-0.81), 0.76 (0.65-0.86) and 0.72 (0.63-0.82) respectively. The CCI came right after with respectively AUROC of 0.69 (0.59-0.79), 0.74 (0.65-0.83) and 0.71 (0.64-0.8). To predict mortality at 12 months after hospitalization, the CCI had the highest AUROC with 0.77 (0.69-0.85), before the 4CMS with 0.69 (0.60-0.79). DISCUSSION: Among 6 scores, the 4CMS was the best to predict intrahospital, 30-day and 6-month mortality. To predict mortality at 12 months, CCI had the best performance before 4CMS. This reflects the importance of considering comorbidities for short- and long-term mortality after COVID 19. REGISTRATION: This study was approved by the ethical committee of Brugmann University Hospital (reference CE 2020/228).

Helical twist controls the thickness of F-actin bundles.

In the presence of condensing agents such as nonadsorbing polymer, multivalent counter ions, and specific bundling proteins, chiral biopolymers typically form bundles with a finite thickness, rather than phase-separating into a polymer-rich phase. Although short-range repulsive interactions or geometrical frustrations are thought to force the equilibrium bundle size to be limited, the precise mechanism is yet to be resolved. The importance of the tight control of biopolymer bundle size is illustrated by the ubiquitous cytoskeletal actin filament bundles that are crucial for the proper functioning of cells. Using an in vitro model system, we show that size control relies on a mismatch between the helical structure of individual actin filaments and the geometric packing constraints within bundles. Small rigid actin-binding proteins change the twist of filamentous actin (F-actin) in a concentration-dependent manner, resulting in small, well defined bundle thickness up to approximately 20 filaments, comparable to those found in filopodia. Other F-actin cross-linking proteins can subsequently link these small, well organized bundles into larger structures of several hundred filaments, comparable to those found in, for example, Drosophila bristles. The energetic tradeoff between filament twisting and cross-linker binding within a bundle is suggested as a fundamental mechanism by which cells can precisely adjust bundle size and strength.

Cytoskeletal polymer networks: viscoelastic properties are determined by the microscopic interaction potential of cross-links.

Although the structure of cross-linking molecules mainly determines the structural organization of actin filaments and with that the static elastic properties of the cytoskeleton, it is largely unknown how the biochemical characteristics of transiently cross-linking proteins (actin-binding proteins (ABPs)) affect the viscoelasticity of actin networks. In this study, we show that the macroscopic network response of reconstituted actin networks can be traced back to the microscopic interaction potential of an individual actin/ABP bond. The viscoelastic response of cross-linked actin networks is set by the cross-linker off-rate, the binding energy, and the characteristic bond length of individual actin/ABP interactions.

Osmotic shrinkage and reswelling of giant vesicles composed of dioleoylphosphatidylglycerol and cholesterol.

The osmotic shrinkage of giant unilamellar dioleoylphosphatidylglycerol (DOPG) vesicles in a hypertonic osmotic solution is investigated. The volume reduction for given membrane area leads to a vesiculation of the bilayer into the interior of the giant. The size of the daughter vesicles that appear inside the giant is uniform and an increasing function of the cholesterol content, but independent of the osmotic gradient applied. The radius of the daughter vesicles increases from 0.2 microm to 3.0 microm when the cholesterol content is changed from 0 to 40%. It is argued that the size of the daughter vesicles is regulated by the membrane persistence length, which is an exponential function of the mean bending modulus. From the kinetics of shrinkage it follows that approximately 14% of the daughter vesicles remain attached to the mother giant. This is in reasonable agreement with osmotic swelling experiments which show that approximately 11% of the daughter vesicles is available for area expansion.

The effect of a low-fat, high-protein or high-carbohydrate ad libitum diet on weight loss maintenance and metabolic risk factors.

BACKGROUND: High-protein (HP) diets are often advocated for weight reduction and weight loss maintenance. OBJECTIVE: The aim was to compare the effect of low-fat, high-carbohydrate (HC) and low-fat, HP ad libitum diets on weight maintenance after weight loss induced by a very low-calorie diet, and on metabolic and cardiovascular risk factors in healthy obese subjects. DESIGN: Forty-eight subjects completed the study that consisted of an energy restriction period of 5-6 weeks followed by a weight maintenance period of 12 weeks. During weight maintenance subjects received maltodextrin (HC group) or protein (HP group) (casein (HPC subgroup) or whey (HPW subgroup)) supplements (2 x 25 g per day), respectively and consumed a low-fat diet. RESULTS: Subjects in the HP diet group showed significantly better weight maintenance after weight loss (2.3 kg difference, P=0.04) and fat mass reduction (2.2 kg difference, P=0.02) than subjects in the HC group. Triglyceride (0.6 mM difference, P=0.01) and glucagon (9.6 pg ml(-1) difference, P=0.02) concentrations increased more in the HC diet group, while glucose (0.3 mM difference, P=0.02) concentration increased more in the HP diet group. Changes in total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, insulin, HOMAir index, HbA1c, leptin and adiponectin concentrations did not differ between the diets. No differences were found between the casein- or whey-supplemented HP groups. CONCLUSIONS: These results show that low-fat, high-casein or whey protein weight maintenance diets are more effective for weight control than low-fat, HC diets and do not adversely affect metabolic and cardiovascular risk factors in weight-reduced moderately obese subjects without metabolic or cardiovascular complications.

Exogenous α-synuclein hinders synaptic communication in cultured cortical primary rat neurons.

Amyloid aggregates of the protein α-synuclein (αS) called Lewy Bodies (LB) and Lewy Neurites (LN) are the pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. We have previously shown that high extracellular αS concentrations can be toxic to cells and that neurons take up αS. Here we aimed to get more insight into the toxicity mechanism associated with high extracellular αS concentrations (50-100 µM). High extracellular αS concentrations resulted in a reduction of the firing rate of the neuronal network by disrupting synaptic transmission, while the neuronal ability to fire action potentials was still intact. Furthermore, many cells developed αS deposits larger than 500 nm within five days, but otherwise appeared healthy. Synaptic dysfunction clearly occurred before the establishment of large intracellular deposits and neuronal death, suggesting that an excessive extracellular αS concentration caused synaptic failure and which later possibly contributed to neuronal death.

Opposing effects of cation binding and hydration on the bending rigidity of anionic lipid bilayers.

We correlate the molecularly realistic self-consistent field predictions for the mean bending modulus kc of charged lipid vesicles with experimental observations of the size R of corresponding vesicles that are produced by the freeze-thaw method. We elaborate on the Ansatz that the bending modulus is related to the membrane persistence length and that this length scale sets the radius of the vesicles. Alkali cations have a remarkable effect on the mean bending modulus and thus on the equilibrium radius of negatively charged entropically stabilized dioleoylphosphatidylglycerol (DOPG) vesicles. Where cation hydration typically results in thicker and thus stiffer membranes, specific adsorption to the bilayer surface results in a decrease of the surface charge density and the thickness of the membrane-associated electric double layer. As a result of these opposing effects on kc and R, the largest DOPG vesicles are found in the presence of K+, which combines an intermediate hydration enthalpy and PG-binding affinity.

Bending rigidity of mixed phospholipid bilayers and the equilibrium radius of corresponding vesicles.

In spite of the large mean bending moduli observed for phospholipid bilayers, stable vesicle phases were recently observed for dilute solutions of charged phospholipids. A correspondingly large negative Gaussian bending modulus associated with charged membranes results in an overall curvature energy that is so low that entropic stabilization is possible. The mean bending modulus determines the membrane persistence length and therefore it is reasonable that there is a correlation between the membrane rigidity and the size of the lipid vesicles. Here we show that in mixtures of the anionic phospholipid dioleoylphosphatidylglycerol and the zwitterionic phospholipid dioleoylphosphatidylcholine the radius of vesicles produced by repetitive freeze-thaw cycles is considerably smaller than expected from the rigidities of the corresponding pure lipid bilayers. Self-consistent field calculations indicate that the changes in the equilibrium radius of mixed bilayers can be attributed to the dependences of the mean bending modulus k(c) on lipid mixing and the average surface charge density.

Basic design features of the parallel alpha beta barrel, a ubiquitous protein-folding motif.

Basic design features of the beta-sheet portion in parallel alpha beta barrels in known protein structures are analysed in the context of a model of a regular hyperboloid. A formal description of the relationships between beta-sheet twist, number of strands in the sheet and barrel dimensions is derived, and the underlying physical principles are rationalized. Results suggest that the major constraints on the geometry of the beta-sheet portion of the barrel come from the requirements to have optimal H-bonding interactions between beta-strands and to closely pack amino acid side-chains in the barrel interior so as to exclude bulk water. In addition, we show how the hyperboloid model and the ensuing formalism can serve to derive useful geometric and graphic tools for computer-aided protein design de novo. We then illustrate how these tools are used to determine that the requirement to have a closed regular eight-stranded beta-sheet surface imposes no particular constraints on the geometry (phi, psi angles) of the polypeptide backbone. Understanding the role of the amino acid sequence in determining the observed structures remains a major challenge. Detailed comparisons of known alpha beta-barrel structures (and amino acid sequence) with each other, and with polypeptide fragments from other protein crystal structures, reveal only a limited number of common sequence-structure motifs. These belong to characteristic alpha beta 1 and alpha beta 3 loop families previously described in alpha beta proteins, and occur at least once in nearly all the alpha beta-barrel structures examined.

The influence of different boundary conditions on the response of the head to impact: a two-dimensional finite element study.

The objective of the present study is to gain a better understanding of the possible importance of skull-brain interface conditions, boundary conditions at the head-neck junction, and brain material properties when modeling the response of the human head to transient loadings. To that end, a two-dimensional plane strain finite element model of a para-sagittal section of a human head has been developed. The model comprises the brain and the skull, with the foramen magnum represented by a force-free opening. The model geometry was obtained from MRI data. The material properties used were adopted from the literature and are homogeneous and isotropic. In all analyses the skull bone was modeled as a linearly elastic material. First, to enable a comparison between simulation results and experiments reported in the literature, the loading conditions, realized in experiments reported in literature, were used as input to the completely linearly elastic model without a kinematic constraint at the head-neck junction. This was done for both rigid coupling and no coupling at the skull-brain interface. Next, various versions of the model were constructed by using different combinations of the following features: linear elastic or viscoelastic brain material properties, different contact conditions at the skull-brain interface, and incorporation of a neck constraint. The results show that both coup and contrecoup pressures are much more sensitive to the type of skull-brain interface condition than to the presence or absence of a force-free foramen magnum. A neck constraint proves to be an important modeling assumption, because of its effect upon the deformation of the brain. The use of different time-dependent deviatoric material parameters for the brain did not significantly change the head's response.

Living and dying with chronic obstructive pulmonary disease.

OBJECTIVE: To characterize chronic obstructive pulmonary disease (COPD) over patients' last 6 months of life. STUDY DESIGN: A retrospective analysis of a prospective cohort from the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT). SETTING: Hospitalization for exacerbation of COPD at five US teaching hospitals. PARTICIPANTS: COPD patients who died within 1 year (n = 416) among 1016 enrolled. METHODS: Interview and medical record data were organized into time windows beginning with death and ending 6 months earlier. OUTCOME MEASURES: Days in hospital, prognosis, illness severity, function, symptoms, patients' preferences, and impacts on families. RESULTS: One-year survival was 59%, 39% had > or = 3 comorbidities, and 15 to 25% of the patients' last 6 months were in hospitals. Exacerbation etiologies included respiratory infection (47%) and cardiac problems (30%). Better quality of life predicted longer survival (ARR: 0.36; 95% CI, 0.19-0.87) as did heart failure etiology of exacerbation (ARR: 0.57; CI, 0.40, 0.82). Estimates of survival by physicians and by prognostic model were well calibrated, although patients with the worst prognoses survived longer than predicted. Patients' estimates of prognosis were poorly calibrated. One-quarter of patients had serious pain throughout, and two-thirds had serious dyspnea. Patients' illnesses had a major impact on more than 25% of families. Patients' preferences for Do-Not-Resuscitate orders increased from 40% at 3 to 6 months before death to 77% within 1 month of death; their decisions not to use mechanical ventilation increased from 12 to 31%, and their preferences for resuscitation decreased from 52 to 23%. CONCLUSIONS: Patients with advanced COPD often die within 1 year and have substantial comorbidities and symptoms. Adequate description anchors improved care.

Dying with lung cancer or chronic obstructive pulmonary disease: insights from SUPPORT. Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments.

CONTEXT: Many are calling for patients with advanced chronic obstructive pulmonary disease (COPD) to receive hospice care, but the traditional hospice model may be insufficient. OBJECTIVE: To compare the course of illness and patterns of care for patients with non-small cell lung cancer and severe COPD. DESIGN: Prospective cohort study of seriously ill, hospitalized adults. SETTING: Five teaching hospitals in the United States. PATIENTS: Patients with Stage III or IV non-small cell lung cancer (n = 939) or acute exacerbation of severe COPD (n = 1008). MAIN OUTCOME MEASURES: Patients' preferences for pattern of care and for ventilator use; symptoms; life-sustaining interventions; and survival prognoses. RESULTS: Sixty percent in each group wanted comfort-focused care; 81% with lung cancer and 78% with COPD were extremely unwilling to have mechanical ventilation indefinitely. Severe dyspnea occurred in 32% of patients with lung cancer and 56% of patients with COPD and severe pain in 28 % of patients with lung cancer and 21% of patients with COPD. Patients with COPD who died during index hospitalization were more likely than patients with lung cancer to receive mechanical ventilation (70.4% vs 19.8%), tube feeding (38.7% vs 18.5%), and cardiopulmonary resuscitation (25.2% vs 7.8%). Mechanical ventilation had greater short term effectiveness in patients with COPD, based on survival to hospital discharge (76% vs 38%). Patients with COPD maintained higher median 2-month and 6-month survival prognoses, even days before death. CONCLUSIONS: Hospitalized patients with lung cancer or COPD preferred comfort-focused care, yet dyspnea and pain were problematic in both groups. Patients with COPD were more often treated with life-sustaining interventions, and short-term effectiveness was comparatively better than in patients with lung cancer. In caring for patients with severe COPD, consideration should be given to implementing palliative treatments more aggressively, even while remaining open to provision of life-sustaining interventions.

Echocardiographic and physiological performance characteristics of triathletes.

BACKGROUND: Endurance sports require a variety of physiological adaptations. OBJECTIVE: To examine the structural and functional heart adaptations and their hemodynamic implications in triathletes. PATIENTS AND METHODS: A group of 52 male triathletes was compared with a control group of 22 healthy male nonathletes. All of the subjects were given a bidimensional cardiac Doppler echocardiography examination and administered maximal exercise tests with lactic acid determinations, on a bicycle ergometer and a treadmill. RESULTS: The triathletes showed clear structural and functional heart adaptations with concentric and eccentric hypertrophy with evidence of a supernormal diastolic left ventricular function. The performance capacity of the triathlete differed significantly from that of the control subject. The maximal oxygen consumption and the maximal oxygen consumption per kilogram on the bicycle and on the treadmill were significantly higher in the triathletes. The same results and conclusions were obtained concerning aerobic capacities and power outputs on a bicycle ergometer at blood lactate concentrations of 2, 3 and 4 mmol/L. The heart rate 6 min after the start of exercise is a significant parameter for the evaluation of the physical condition of a subject. The lactic acid determinations during the recovery phase enabled important conclusions to be drawn about the physical condition of the subjects. CONCLUSIONS: The triathletes showed evidence of important structural and functional heart adaptations with hemodynamic implications. The maximal performing capacities, on the bicycle as well as on the treadmill, were distinctly higher in the triathlete group. Furthermore, the aerobic and anaerobic capacities were significantly different between the groups. In this context, the heart rate 6 min after the start of exercise and the blood lactate concentrations 20 min after the maximal exercise test were significant parameters. It was not always the best triathletes who had the most significant structural cardiac adaptations. Thus, the 'athletic heart' syndrome as a physiological entity is questioned.

Structural heart adaptations in triathletes.

OBJECTIVE: To perform a triathlon in aerobic conditions, a variety of cardiovascular, haemodynamic and metabolic adaptations are required. The heart is the central concern and also the most important limiting factor. In this study we investigate the structural and functional heart adaptations of a group of triathletes. METHODS AND RESULTS: A group of 52 male triathletes was divided into 4 subgroups in function of their athletic results and compared with a control group of 22 healthy, very active but no athletic men. The groups had comparable anthropometric and general physical characteristics. Very significant differences in cardiac structure and cardiac function were observed between the groups. In the triathletes, we registered distinct signs of significantly mixed eccentric and concentric hypertrophy. Unlike the findings in a pathological left ventricular hypertrophy, the diastolic left ventricular function in triathletes was completely normal and even better than in the control group. The late passive diastolic filling period of the triathlete, in particular, seemed to have specific characteristics. The comparison between the subgroups of triathletes shows us that genetic factors probably play an important role in the cardiac adaptations in triathletes. CONCLUSIONS: In our opinion the "athletic heart" in triathletes is not a specific "physiological entity" but is a transitional phase to a dilated hypertrophic cardiomyopathy. Our study yields some arguments for the following proposition: "People are born as elite athletes, with specific characteristics of the left ventricle and with a specifically supernormal diastolic left ventricular function."

Supernormal left ventricular diastolic function in triathletes.

We studied the structural and functional heart adaptations of 52 male triathletes compared with those of 22 active, nonathletic men, by 2-dimensional Doppler echocardiography. Left ventricular diastolic function was evaluated by recording transmitral flow velocities. To exclude the influences of preload, left atrial pressure, and aortic pressure, left ventricular diastolic function was also evaluated by pulsed Doppler tissue imaging. Significant differences in cardiac structure and function were observed between the 2 groups. In the triathletes, the left ventricular diastolic function was completely normal, despite signs of mixed eccentric and concentric left ventricular hypertrophy, and this function was better than that in the control group. We measured 2 aspects of the late passive diastolic filling period in the triathletes: ASEAC value (the amplitude of excursion of the interventricular septal endocardium at the end of left ventricular diastole just after atrial contraction); and the time between onset of the P wave on the electrocardiographic tracing and onset of systolic septal movement on M-mode echocardiography. Pulsed Doppler tissue imaging confirmed these results. The E/A ratios (peak early left ventricular diastolic motion velocity divided by the peak atrial systolic motion velocity), measured by pulsed Doppler tissue imaging, yielded even more evidence for supernormal left ventricular diastolic function in the triathletes. Left ventricular relaxation and filling properties were measured along the longitudinal and transverse axes by pulsed Doppler tissue imaging, which was useful for evaluating left ventricular diastolic function. We determined that triathletes may develop supernormal left ventricular diastolic function with increased diastolic reserves.