Papers by Arno Schmidt-trucksäss
Zeitschrift für Gerontologie + Geriatrie
Age-related morphological changes in the cardiovascular system refer to a thickening of the arter... more Age-related morphological changes in the cardiovascular system refer to a thickening of the arterial wall as well as a diffuse increase in the wall thickness of the myocardium. In terms of function, this leads to a decrease of the myocardial contractility in systole and to a delay of the diastolic myocardial relaxation. At the arterial wall, an impairment of wall elasticity as well as a decrease of the vasoreagibility can be observed. The systolic blood pressure and the blood pressure amplitude rise; the blood flow-dependent vasodilatation mediated by endothelial cells decreases. The loss of cardiac pacemaker cells by approximately 90% from the 2nd to the 8th decade leads to a reduction of the heart rate variability and to a decrease of the maximum heart rate during exhaustive physical exercise. Hemodynamically these changes resulted in a continuous decline of the maximum cardiac output as well as the maximum oxygen transport capacity. Between the 3rd and 8th decade the peripheral skeletal muscle mass decreases as a result of a reduction of the size and the number of muscle fibers with an overproportional loss of 30-40% regarding the highly glycolytic type IIb fibers. Furthermore, the intramuscular capillarization declines so that, with a concomitant decrease in the number and size of the mitochondria, the supply with oxygen and energy sources and consecutively the aerobic muscular energy metabolism decreases by 8-10% per decade beginning with the 4th to 5th decade. Additionally, the maximum and explosive muscular strength decreases by 30-35% from the 4th decade onwards. In older, healthy men who perform a regular aerobic muscular training in endurance sport disciplines (e.g., walking, jogging or cycling), a decrease of the resting heart rate, a restoration of the primarily lowered heart rate variability, an improvement of the early diastolic left-ventricular filling as well as a significant increase in the VO2max could be proven. Other studies showed that regular endurance training on a cycle-ergometer resulted in a significant increase in capillarization within the exercising muscle groups. In older, trained individuals a reduced stiffness of the arterial vessel walls and an improved maximum exercise-induced muscular blood supply occurs. In other training studies performed with older subjects, a positive influence of regular endurance training on the carbohydrate metabolism along with an improvement of the primarily reduced insulin sensitivity could be demonstrated. In older men and women who regularly underwent muscular strength training, a significant increase in maximum strength with a significant increase in the proportion of type II muscle fibers was found.
Journal of Applied Physiology
Arterial properties of the carotid and femoral artery in endurance-trained and paraplegic subject... more Arterial properties of the carotid and femoral artery in endurance-trained and paraplegic subjects. relationships of blood flow changes to structure, function, and shear rate of conducting arteries have not been thoroughly examined. Therefore, the purpose of this study was to investigate these parameters of the elastic-type, common carotid artery (CCA) and the muscular-type, common femoral artery (CFA) in long-term highly active and extremely inactive individuals, assuming that the impact of activity-induced blood flow changes on conduit arteries, if any, should be seen in these subjects. We examined 21 highly endurance-trained athletes (A), 10 paraplegic subjects (P), and 20 sedentary subjects (S) by means of noninvasive ultrasound. As a result, the CFA diameter and compliance were highest in A (9.7 Ϯ 0.81 mm; 1.84 Ϯ 0.54 mm 2 /kPa) and lowest in P (5.9 Ϯ 0.7 mm; 0.54 Ϯ 0.27 mm 2 /kPa) compared with S (8.3 Ϯ 1.0 mm; 0.92 Ϯ 0.48 mm 2 /kPa) with P Ͻ 0.01 among the groups. Both parameters correlated with each other (r ϭ 0.62; P Ͻ 0.01). Compared with A (378 Ϯ 84 s Ϫ1 ; 37 Ϯ 15 s Ϫ1 ) and S (356 Ϯ 113 s Ϫ1 ; 36 Ϯ 20 s Ϫ1 ), the peak and mean shear rates of the CFA were almost or more than doubled in P (588 Ϯ 120 s Ϫ1 ; 89 Ϯ 26 s Ϫ1 ). In the CCA, only the compliance and peak shear rate showed significant differences among the groups (A: 1.28 Ϯ 0.47 mm 2 /kPa, 660 Ϯ 138 s Ϫ1 ; S: 1.04 Ϯ 0.27 mm 2 /kPa, 588 Ϯ 109 s Ϫ1 ; P: 0.65 Ϯ 0.22 mm 2 /kPa, 490 Ϯ 149 s Ϫ1 ; P Ͻ 0.05). In conclusion, the results suggest a structural and functional adaptation in the CFA and a predominantly functional adaptation of the arterial wall properties to differences in the physical activity level and associated exercise-induced blood flow changes in the CCA. The results for humans confirm those from animal experiments. Similar shear rate values of S and P in the CFA support the hypothesis of constant shear stress regulation due to local blood flow changes in humans. On the other hand, the increased shear rate in the CFA in P indicates an at least partially nonphysiological response of the arterial wall in long-term chronic sympathectomy due to a change in local blood flow. arterial diameter; compliance; shear rate; physical activity; ultrasound Address for reprint requests and other correspondence: A. Schmidt-Trucksä ss, Freiburg
Atherosclerosis, 2015
Inflammatory risk factors in childhood, e.g. obesity, impact on carotid artery intima media thick... more Inflammatory risk factors in childhood, e.g. obesity, impact on carotid artery intima media thickness (CIMT), an early indicator of atherosclerosis. Little is known on potential infectious origins in childhood. We investigated the association between number of reported different childhood infectious diseases and CIMT in adolescence. 288 SAPALDIA offspring (8-21years) underwent a clinical examination in 2010-2011: anthropometry, blood pressure, CIMT, blood draw (cardiovascular biomarkers, cotinine). Offspring and parents gave information on individuals' and family health, child's vaccination status, infectious diseases and other early life factors. Life-time prevalence of bronchitis, pneumonia, tonsillitis, otitis, mononucleosis, meningitis, appendicitis, and scarlet fever were investigated, separately, and as cumulative infectious disease score. Multilevel adjusted linear regression analysis on the association between subjects' CIMT average and infectious diseases score was performed, stratifying by sex. Youth (mean age 14.8 yrs; 53% female) reported on average 1.3 of the listed infectious diseases; 22% boys and 15% girls reported ≥3 infectious diseases (p = 0.136). Two-thirds were vaccinated according to recommendations (boys 56%, girls 61.5%, p = 0.567). Sex-stratified analyses yielded significantly increased CIMT in boys with ≥3 infectious diseases vs. none (0.046 mm, 95%CI 0.024; 0.068). In girls, the effect was of same direction but statistically non-significant (0.011 mm, 95%CI -0.015; 0.036). The SAPALDIA Youth study complements current evidence on infectious origins of atherosclerosis in adults. The larger effects observed in boys may relate to a higher vulnerability of the vasculature and/or to infectious pathogens. Our data are suggestive of an early impact of childhood infectious diseases on vascular health.
International Journal of Sports Medicine
Autonomic dysreflexia presents a special situation in high-lesion spinal cord injury, however, in... more Autonomic dysreflexia presents a special situation in high-lesion spinal cord injury, however, intentionally or self-induced autonomic dysreflexia directly before or during competition to increase performance, so called 'boosting', is also being reported. In order to examine the influence of autonomic dysreflexia on plasma catecholamines, cardiocirculatory and metabolic parameters, 6 spinal cord injured wheelchair athletes with high-level lesions underwent wheelchair ergometry without (ST1) and with (ST2) autonomic dysreflexia. At the point of exhaustion significantly higher values for norepinephrine and epinephrine were observed in ST2 than in ST1. During autonomic dysreflexia a significantly higher peak performance (77.5 vs. 72.5 watt), higher peak heart rate (161 vs. 149 x min(-1)), and peak oxygen consumption (1.96 vs. 1.85 l x min(-1)), with comparable peak lactate (7.11 vs. 7.00 mmol x l(-1)) were reached on average. The blood pressure values in ST2 were partially hypertensive and higher than in ST1. In conclusion, autonomic dysreflexia, as a sympathetic spinal reflex, leads to a higher release of catecholamines during exercise. This results in higher peak performance, peak heart rate, peak oxygen consumption, and higher blood pressure values. The peak lactate, as an indicator of the anaerobic lactate metabolism, was unchanged. However, autonomic dysreflexia presents an unpredictable risk, caused predominantly by hypertensive blood pressure values, for high-lesion spinal cord injured persons at rest and more so during exercise; it is seen as a prohibited manipulation by the doping guidelines of the International Paralympic Committee.
Therapeutische Umschau
Regular physical exercise has shown to be beneficial for patients with cardiovascular disease. Th... more Regular physical exercise has shown to be beneficial for patients with cardiovascular disease. Therefore cardiac rehabilitation in Germany is continued for years after hospital discharge in outpatient cardiac exercise groups which meet twice a week under the guidance of a physician and a sports instructor. Before participation cardiac patients have to be examined including exercise tests and echocardiography for assessment of contraindications for exercise therapy as well as individual exercise capacity. Patients are assigned to two groups with different levels of exercise intensity according to their symptom-free work-capacity (cutoff level 1 W/kg). During exercise sessions sports-specific forms of exercise such as stretching, aerobic exercise or ball games are accompanied by psychosocial elements such as stress management. This global approach is intended to improve cardiovascular risk factors, cardiac function, and work capacity as well as to stabilize the patient psychologically in order to accelerate social integration. Recently these groups have opened towards patients after cardiac transplantation or with severe heart failure. Therefore, cardiac exercise groups play a central role in cardiac rehabilitation long after the acute cardiac event.
Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine
Chronic dynamic exercise leads to regulative and structural adaptations of the heart (athlete&... more Chronic dynamic exercise leads to regulative and structural adaptations of the heart (athlete's heart). To what extent the enlargement and physiologic hypertrophy of the heart lead to changes in the function of the valves, particularly regurgitation, is not yet clear. The aim of this study was to examine the regurgitation levels of different states of "athlete's heart." Our study population consisted of 5124 healthy subjects (4046 male and 1078 female, 18-60 years), regularly exercising 1 to 20 h/wk. Subjects were divided into 3 groups depending on their relative heart volumes (RHVs): (1) very enlarged heart group (VEHG; male, n = 1251; female, n = 201), with RHVs of greater than 14 (male) and 13 (female) mL/kg; (2) mildly enlarged heart group (MEHG; male, n = 702; female, n = 224), with RHVs of 12 to 14 (male) and 11 to 13 (female) mL/kg; and (3) control subjects (CS; male, n = 2093; female, n = 653), with RHVs of less than 12 (male) and 11 (female) mL/kg. According to US Food and Drug Administration criteria for valve regurgitation, it could be shown by Doppler sonography that as physiologic enlargement and hypertrophy increased significantly, the frequency and severity of aortic valve regurgitation (mean +/- SD: VEHG, 0.04 +/- 0.09; MEHG, 0.09 +/- 0.10; CS, 0.10 +/- 0.11; P < .05) and high mitral regurgitation (VEHG, 0.10 +/- 0.17; MEHG, 0.20 +/- 0.29; CS, 0.26 +/- 0.32; P < .01) decreased. On the contrary, pulmonary regurgitation (VEHG, 0.79 +/- 0.45; MEHG, 0.47 +/- 0.33; CS, 0.35 +/- 0.38; P < .01) and tricuspid valve regurgitation (VEHG, 0.42 +/- 0.29; MEHG, 0.47 +/- 0.33; CS, 0.35 +/- 0.38; P < .01) increased highly significantly with heart size. These findings strongly support the view of athlete's heart as a physiologic adaptation of the heart, at least on the left side, not causing increased valvular regurgitation.
PloS one, 2015
ClinicalTrials.gov NCT01771445.
Hintergrund Seit in den 1980er Jahren erste wissenschaftliche Studien die negativen gesundheitlic... more Hintergrund Seit in den 1980er Jahren erste wissenschaftliche Studien die negativen gesundheitlichen Folgen von Passivrauchen nachgewiesen haben, werden Rauchverbote in öffentlichen Räumen kontrovers diskutiert. Die Weltgesundheitsorganisation erliess 2003 ein Rahmenübereinkommen zur Eindämmung des Tabakkonsums, das von 168 Staaten unterschrieben und inzwischen von 176 ratifiziert wurde. Seither wurden in mehreren Ländern Rauchverbote in öffentlichen Räumen und an Arbeitsplätzen eingeführt. Begleitend wurden oft Studien zu Rauchexposition und Gesundheitsfaktoren von Gastgewerbemitarbeitern durchgeführt, mit unterschiedlichen Methoden. Die Exposition wurde meistens anhand von Fragebogen oder unter Anwendung eines Proxys wie PM2.5 eingeschätzt, was jedoch ungenau sein kann. Die Nikotinmessung von biologischen Proben wie Urin, Blut oder Speichel kann ausserdem vom persönlichen Metabolismus beeinflusst werden und reflektiert daher in erster Linie die kurzfristige Belastung. Bezüglich der Gesundheit konzentrierten sich die meisten Studien auf respiratorische Untersuchungen und Symptomerhebungen. Kardiovaskuläre Auswirkungen des Passivrauchens wurden bisher beim Gastronomiepersonal kaum untersucht. Mit der vorliegenden Studie sollten einige dieser Lücken gefüllt werden. Im Mai 2010 wurde in der Schweiz das erste Bundesgesetz zum Schutz der Bevölkerung vor Passivrauchen eingeführt. Da die lose Regelung Raum für Ausnahmen liess, war es weiterhin möglich, kleine Raucherlokale oder abgetrennte Rauchräume von begrenzter Grösse zu führen. Die COSIBAR Studie nutzte die Umsetzung des Bundesgesetzes als natürliche Intervention für eine Untersuchung der Exposition und kardio-respiratorischen Gesundheit bei nichtrauchenden Gastgewerbemitarbeitern.
Journal of Applied Physiology
The purpose of this study was to investigate the influence of different injury levels in persons ... more The purpose of this study was to investigate the influence of different injury levels in persons with spinal cord injury (SCI) on epinephrine (Epi) and norepinephrine (NE) at rest and during graded wheelchair exercise and the related changes in heart rate and O2 uptake (VO2). Twenty tetraplegics (Tetra), 10 high-lesion paraplegics (HLPara), 20 paraplegics with SCI below T5 (MLPara), and 18 able-bodied, nonhandicapped persons (AB) were examined. Because of the higher level of interruption of the sympathetic pathways, Tetra persons showed lower Epi and NE at rest and only slight increases during exercise compared with all other groups; the Tetra subjects' impaired cardiac sympathetic innervation caused restricted cardioacceleration and strongly reduced maximal VO2. When compared with AB persons, HLPara had comparable NE but lower Epi levels as a result of partial innervation of the noradrenergic system and denervation of the adrenal medulla. MLPara subjects showed an augmented basal and exercise-induced upper spinal thoracic sympathetic activity compared with AB subjects. The increase in heart rate in relation to VO2 was higher in HLPara because of a smaller stroke volume as a result of venous blood pooling. The different exercise response in persons with SCI is a result of the interruption of pathways in the spinal cord to the peripheral sympathetic nervous system in addition to the motor paralysis.
Proceedings 10th International Conference on Image Analysis and Processing, 1999
This study presents a novel automatic system for detecting the intimal and adventitial layers of ... more This study presents a novel automatic system for detecting the intimal and adventitial layers of the far common carotid artery (CCA) by applying the snake techniques. Cohen's snake is also modified and some criteria are added for our applications. In addition, the oscillating problem of using snakes is solved by properly choosing the time step from analysis of the frequency response of the filters. The snake scheme combined with a time diminishing gravity window and an external force makes it possible to detect the intima-media complex of the far CCA. Besides, a cost function assists the snake in selecting the optimal shape of adventitia layer. This mechanism is also helpful when there are plaques on the CCA wall. Moreover, this study compares the proposed snake and ziplock snake with respect to the manual extraction contour. According to that comparison, the system can automatically detect the intimal and adventitial layers. In addition to that it does not need any manual correction and it is noise-resistant, the proposed system allows a user to quantitatively measure an important predictor of heart infarction and strokes.
Diabetologie und Stoffwechsel, 2006
Lecture Notes in Computer Science, 2007
In this paper, we introduce a novel unsupervised segmentation method using a histogram fitting me... more In this paper, we introduce a novel unsupervised segmentation method using a histogram fitting method to find out the optimal histogram clustering based on multi Gaussian models. The fitting problem is performed via the trust region reflective Newton method to minimize a predefined cost function. The histogram clustering is the global information describing the probability of a given gray value
Lecture Notes in Computer Science, 2009
In this paper, we propose a novel method for automatic detection of the lumen diameter and intima... more In this paper, we propose a novel method for automatic detection of the lumen diameter and intima-media thickness from dynamic B-mode sonographic image sequences with and without plaques. There are two phases in this algorithm. In the first phase a dual dynamic programming (DDP) is applied to detect the far wall IMT and near wall IMT. The general median curves are then calculated. In the second phase, the DDP is applied again using the median curves as the knowledge to obtain a more informed search and to potentially correct errors from the first phase. All results are visually controlled by professional physicians. Based on our experiments, this system can replace the experts' manual work, which is time-consuming and not repeatable. (a) (b) (c) © © Fig. 1. A typical B-mode sonographic image. (a) A sub-image from a dynamic image sequence. (b) The DDP result superimposed on the sub-image of Frame No. 43. (c) The DDP result on Frame No. 45. © © © Fig. 2. The far wall IMT and plaque detection: The first column are the raw sub-images; they are frame No. 38, 41, 44, and 47, respectively. The second column are the results of DDP superimposed on the raw sub-images. The third column are the results of proposed scheme superimposed on the raw sub-images.
3rd IEEE International Symposium on Biomedical Imaging: Macro to Nano, 2006., 2006
We present a novel method for detecting the intima and adventitia of carotid artery in B-mode son... more We present a novel method for detecting the intima and adventitia of carotid artery in B-mode sonographic images. This method simultaneously detects both layers with the anatomic information of these layers to reduce the influence of noises. We have tested the method on images made from different sonographic instrumentation. A comparison between automatic detection and professional manual tracing is performed. The results show that this method can be applied directly on these instrumentation with few modifications.
PLOS ONE, 2015
Regular physical activity has been shown to reduce cardiovascular disease risk in the general pop... more Regular physical activity has been shown to reduce cardiovascular disease risk in the general population. While smaller studies in specified groups (highly trained versus untrained individuals) indicate a certain dose-dependent effect of physical activity on the reduction of carotid stiffness (an indicator of subclinical vascular disease), it is unclear whether this association is present in a representative sample. Thus, we investigated this question cross-sectionally in participants from the population-based Swiss Cohort Study on Air Pollution And Lung and Heart Diseases In Adults (SAPALDIA). Self-reported total, moderate and vigorous physical activity and distensibility as a measure of local arterial stiffness among 1636 participants aged 50 to 81 years without clinically manifest diseases were evaluated. Mixed regression models were used to examine associations of physical activity intensity with distensibility. Vigorous physical activity, but not total nor moderate physical activity, was significantly associated with increased distensibility (= reduced carotid stiffness) in univariate analyses (percent change in the geometric mean and 95% confidence interval per 1 standard deviation increment in vigorous physical activity = 2.54 (0.69; 4.43), p<0.01; in total physical activity = 1.62 (-0.22; 3.50), p = 0.08; in moderate physical activity = 0.70 (-1.12; 2.56), p = 0.45). These associations disappeared when we additionally adjusted for age. After adjustment for the most important confounders and risk factors, we found no evidence for an association of physical activity with carotid stiffness in the general middle aged to elderly population.
European Geriatric Medicine, 2012
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Papers by Arno Schmidt-trucksäss