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| 2. |
- Hedman, Kristofer, 1984-
(författare)
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Cardiac function and long-term volume load : Physiological investigations in endurance athletes and in patients operated on for aortic regurgitation
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background and aims. The heart is a remarkably adaptable organ, continuously changing its output to match metabolic demands and haemodynamic load. But also in long-term settings, such as in chronic or repeated volume load, there are changes in cardiac dimensions and mass termed cardiac hypertrophy. Depending on the stimulus imposing the volume load this hypertrophy differs in extent and phenotype. We aimed to study cardiac function in two settings with long-term volume load, including patients previously operated for aortic regurgitation and healthy females performing endurance training.Methods. In paper I, 21 patients (age 52±12 years, all male) operated on with aortic valve replacement for aortic regurgitation (AR) underwent a cardiopulmonary exercise test (CPET) and an echocardiographic evaluation in average 49±15 months following surgery. The peak oxygen uptake (peakVO2) was compared to results from a pre-operative and a six months follow-up, and relations to echocardiographic measures were determined.In papers II–IV, 48 endurance trained female athletes (ATH, age 21±2 years) were compared to 46 untrained females (CON, age 21±2 years) regarding echocardiographic measures of cardiac dimensions, global and regional cardiac function and maximal aerobic capacity (VO2max) determined with CPET. Relations between VO2max and cardiac variables were explored.Results. In paper I, peakVO2 had decreased from 26±6 to 23±5 mL/kg/min in patients from the first to second, late follow-up. This decrease was larger than expected by their increased age alone, and a majority of patients had a cardiorespiratory fitness below average according to reference values from healthy subjects of the same age, sex and weight.In papers II–IV, we found that ATH (VO2max 52±5 mL/kg/min) had larger atrial, ventricular and inferior vena cava dimensions compared to CON (VO2max 39±5 mL/kg/min). ATH had increased measures of right ventricular (RV) systolic function (RV atrioventricular plane displacement indexed by cardiac length 2.5±0.3 vs. 2.3±0.3, p=0.001) and left ventricular (LV) diastolic function (mitral E-wave velocity 0.92±0.17 vs. 0.86±0.11 m/s, p=0.029). In addition, systolic synchrony was similar between groups while there were heterogeneous differences in diastolic and systolic function across different myocardial segments. VO2max was most strongly related to LV end-diastolic volume (r=0.709, p<0.001).Conclusions. Decreasing peakVO2 following surgery for AR, despite a normalisation in cardiac dimension could either be a result of a remaining, slight myocardial dysfunction or post-operative negative influence on cardiac performance by filling disturbances or the prosthetic valve itself, or, a sign of an inadequate post-operative level of physical activity and lack of exercise training. This stresses the importance of post-operative management and methods for increasing aerobic capacity, where exercise testing could be valuable for guiding patients and tailoring exercise protocols.The eccentric cardiac hypertrophy in ATH, symmetrically distributed across the heart, depicts the physiological hypertrophy in response to volume load in endurance training. Cardiac function was similar, or for some measures slightly improved in ATH compared to CON and LV dimensions, rather than cardiac function, were predictors of VO2max. As the heart of female athletes has been far less studied than that in males, our results add knowledge regarding the female athlete’s heart, and our results of differences in segmental cardiac function merits further research.
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| 3. |
- Hedman, Kristofer, et al.
(författare)
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Cardiac systolic regional function and synchrony in endurance trained and untrained females
- 2015
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Ingår i: BMJ Open Sport & Exercise Medicine. - : BMJ. - 2055-7647. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Most studies on cardiac function in athletes describe overall heart function in predominately male participants. We aimed to compare segmental, regional and overall myocardial function and synchrony in female endurance athletes (ATH) and in age-matched sedentary females (CON).Methods In 46 ATH and 48 CON, echocardiography was used to measure peak longitudinal systolic strain and myocardial velocities in 12 left ventricular (LV) and 2 right ventricular (RV) segments. Regional and overall systolic function were calculated together with four indices of dyssynchrony.Results There were no differences in regional or overall LV systolic function between groups, or in any of the four dyssynchrony indices. Peak systolic velocity (s′) was higher in the RV of ATH than in CON (9.7±1.5 vs 8.7±1.5 cm/s, p=0.004), but not after indexing by cardiac length (p=0.331). Strain was similar in ATH and CON in 8 of 12 LV myocardial segments. In septum and anteroseptum, basal and mid-ventricular s′ was 6–7% and 17–19% higher in ATH than in CON (p<0.05), respectively, while s′ was 12% higher in CON in the basal LV lateral wall (p=0.013). After indexing by cardiac length, s′ was only higher in ATH in the mid-ventricular septum (p=0.041).Conclusions We found differences between trained and untrained females in segmental systolic myocardial function, but not in global measures of systolic function, including cardiac synchrony. These findings give new insights into cardiac adaptation to endurance training and could also be of use for sports cardiologists evaluating female athletes.
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| 4. |
- Hedman, Kristofer, et al.
(författare)
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ECHOCARDIOGRAPHIC CHARACTERIZATION OF THE INFERIOR VENA CAVA IN TRAINED AND UNTRAINED FEMALES
- 2016
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Ingår i: Ultrasound in Medicine and Biology. - : ELSEVIER SCIENCE INC. - 0301-5629 .- 1879-291X. ; 42:12, s. 2794-2802
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to explore the long-and short-axis dimensions, shape and collapsibility of the inferior vena cava in 46 trained and 48 untrained females (mean age: 21 +/- 2 y). Echocardiography in the subcostal view revealed a larger expiratory long-axis diameter (mean: 24 +/- 3 vs. 20 +/- 3 mm, p amp;lt; 0.001) and short-axis area (mean: 5.5 +/- 1.5 vs. 4.7 +/- 1.4 cm(2), p = 0.014) in trained females. IVC shape (the ratio of short-axis major to minor diameters) and the relative decrease in IVC dimension with inspiration were similar for the two groups. The IVC long-axis diameter reflected short-axis minor diameter and was correlated to maximal oxygen uptake (r = 0.52, p amp;lt; 0.01). In summary, the results indicate that trained females have a larger IVC similar in shape and respiratory decrease in dimensions to that of untrained females. The long-axis diameter corresponded closely to short-axis minor diameter and, thus, underestimates maximal IVC diameter. (E-mail: kristofer.hedman@liu.se) (C) 2016 The Authors. Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine amp; Biology.
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| 5. |
- Hedman, Kristofer, et al.
(författare)
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Female athlete's heart : Systolic and diastolic function related to circulatory dimensions
- 2015
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley-Blackwell. - 0905-7188 .- 1600-0838. ; 25:3, s. 372-381
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Tidskriftsartikel (refereegranskat)abstract
- There are relatively few studies on female athletes examining cardiac size and function and how these measures relate to maximal oxygen uptake (VO2max ). When determining sports eligibility, it is important to know what physiological adaptations and characteristics may be expected in female athletes, taking body and cardiac size into account. The purposes of this study were (a) to compare right and left heart dimensions and function in female endurance athletes (ATH) and in non-athletic female controls of similar age (CON); and (b) to explore how these measures related to VO2max . Forty-six ATH and 48 CON underwent a maximal bicycle exercise test and an echocardiographic examination at rest, including standard and color tissue Doppler investigation. All heart dimensions indexed for body size were larger in ATH (all P < 0.01). The diastolic mitral E/A ratio was 27% higher in ATH (P < 0.001) while systolic left and right atrio-ventricular longitudinal displacement was 7% (P = 0.002) and 15% (P < 0.001) larger in ATH, respectively. Half (50.3%) of the variability in VO2max could be explained by left ventricular end-diastolic volume. Our results could be useful in evaluating female endurance athletes with suspected cardiac disease and contribute to understanding differences between female athletes and non-athletes.
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| 6. |
- Hedman, Kristofer, et al.
(författare)
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The size and shape of the inferior vena cava in trained and untrained females in relation to maximal oxygen uptake
- 2015
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background. The increase in cardiac dimensions following endurance training is well acknowledged. A few studies report a larger inferior vena cava (IVC) in trained, predominatly male subjects while athlete-control studies upon females are lacking. Previous studies were constrained to long-axis measurements, and there are no reports in the literature on IVC short-axis dimensions and shape in athletes.Methods and Results. Forty-eight sedentary and 46 endurance trained females (mean age 21±2 years, VO2max 39±5 vs. 52±5 mL×kg-1×min-1, p<0.001) underwent echocardiographic examination including IVC diameter and cross-sectional area measured in the subcostal view. IVC shape was calculated as the ratio of short-axis major-to-minor diameter.Five out of eight IVC dimensions were larger in trained females, including maximal long-axis diameter (mean 24±3 vs. 20±3 mm, p<0.001) and maximal short-axis area (mean 5.5±1.5 vs. 4.7±1.4 cm2, p=0.022). Both groups presented with a slightly oval IVC with no differences between the groups in IVC shape or inspiratory decrease in any IVC dimension. The IVC long-axis diameter reflected the minor-axis diameter obtained in the short-axis view, during both expiration and inspiration. Positive correlations were seen between maximal IVC long-axis diameter and maximal oxygen uptake (r=0.52, p<0.01), left ventricular end-diastolic volume (r=0.46, p<0.01) and right atrial area (r=0.49, p<0.01).Conclusion. The IVC was larger in endurance trained than in untrained females but showed similar shape and inspiratory decrease in dimensions. The long-axis IVC diameter was related to maximal oxygen uptake.
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| 7. |
- Kvernby, Sofia, et al.
(författare)
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Longitudinal Changes in Myocardial T-1 and T-2 Relaxation Times Related to Diffuse Myocardial Fibrosis in Aortic Stenosis; Before and After Aortic Valve Replacement
- 2018
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Ingår i: Journal of Magnetic Resonance Imaging. - : WILEY. - 1053-1807 .- 1522-2586. ; 48:3, s. 799-807
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diffuse myocardial fibrosis is associated with adverse outcomes, although detection and quantification is challenging. Cardiac MR relaxation times mapping represents a promising imaging biomarker for diffuse myocardial fibrosis. Purpose: To investigate whether relaxation times can detect longitudinal changes in myocardial tissue composition associated with diffuse fibrosis in patients with severe aortic stenosis (AS) before and after aortic valve replacement (AVR). Study type: Prospective longitudinal study. Population/Subjects/Phantom/Specimen/Animal Model: Fifteen patients with severe AS. Field Strength/Sequence: 3T /3(3) 3(3) 5-MOLLI, T2-GraSE, and 3D-QALAS. Assessment: Patients underwent MR examinations at three timepoints: before AVR, as well as 3 and 12 months after AVR. Data from each patient was analyzed in 16 myocardial segments. Statistical Tests: The segment-wise T1 and T2 data were analyzed over time after surgery using linear mixed models for repeated measures analysis. Results: The results showed that T1 relaxation times were significantly (Pamp;lt; 0.05) shorter 3 and 12 months postoperative than preoperative and that the T2 relaxation times were significantly (Pamp;lt; 0.05) longer 3 and 12 months postoperative than preoperative for both 3D and 2D mapping methods. No significant changes were seen between 3 and 12 months postoperative for any of the methods (P50.06/0.19 for T1 with 3D-QALAS/MOLLI and P50.09/0.25 for T2 with 3DQALAS/ GraSE). Data Conclusion: We demonstrated that changes in myocardial relaxation times and thus tissue characteristics can be observed within 3 months after AVR surgery. The significant changes in relaxation times from preoperative examinations to the follow-up may be interpreted as a reduction of interstitial fibrosis in the left ventricular wall. Level of Evidence: 1 Technical Efficacy: Stage 3
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| 8. |
- Nilsson, Henric, et al.
(författare)
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Cardiopulmonary exercise testing for evaluation of a randomized exercise training intervention following aortic valve replacement
- 2019
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Ingår i: Clinical Physiology and Functional Imaging. - : WILEY. - 1475-0961 .- 1475-097X. ; 39:1, s. 103-110
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Tidskriftsartikel (refereegranskat)abstract
- Aortic valve surgery is the definitive treatment for aortic stenosis (AS). No specific recommendation is available on how exercise training should be conducted and evaluated after aortic valve replacement (AVR). This study aimed to examine the effect of aerobic exercise training on exercise capacity following AVR. In addition to our primary outcome variable, peak oxygen uptake (peakVO(2)), the effect on submaximal cardiopulmonary variables including oxygen uptake kinetics (tau), oxygen uptake efficiency slope (OUES) and ventilatory efficiency (VE/VCO2 slope) was evaluated. Following AVR due to AS, 12 patients were randomized to either a group receiving 12 weeks of supervised aerobic exercise training (EX) or a control group (CON). Exercise capacity was assessed by a maximal cardiopulmonary exercise test (CPET). There was a significant increase in peak load (+28%, P = 0 center dot 031) and in peakVO(2) (+23%, P = 0 center dot 031) in EX, corresponding to an increase in achieved percentage of predicted peakVO(2) from 88 to 104% (P = 0 center dot 031). For submaximal variables, there were only non-statistically significant trends in improvement between CPETs in EX. In CON, there were no significant differences in any maximal or submaximal variable between CPETs. We conclude that 12 weeks of supervised aerobic exercise training induces significant adaptations in cardiopulmonary function following AVR, especially in regard to maximal variables including peakVO(2). In addition, we provide novel data on the effect on several submaximal variables following exercise training in this group of patients.
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| 9. |
- Tamás, Éva, 1968-, et al.
(författare)
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Decision support for assessment of left ventricular diastolic function
- 2018
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Ingår i: Physiological Reports. - : John Wiley & Sons. - 2051-817X. ; 6:16
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Tidskriftsartikel (refereegranskat)abstract
- Echocardiographic assessment of the left ventricular diastolic function (LVDF), an integrated part of evaluation of left ventricular function is still a delicate task and is performed with substantial inter-rater variability. Therefore, we aimed to create and evaluate a guidelines-based automated decision support. An algorithm was created for a hierarchical analysis of LVDF based on variables as recommended by the latest guidelines. Age-adjusted normal ranges were pooled from previously published studies into an integrated reference table. For proof-of-concept, 20 echocardiographic examinations were analyzed offline by four experienced physicians with more than 10 years of echocardiographic experience. The first assessments were to be performed as they would be in the clinical practice. Six months later, the assessments were repeated based on the 2017 ASE/EACVI guidelines. The overall inter-rater agreement for the first clinical assessments was moderate, while the guidelines-based assessments had only fair inter-rater agreement. Both kinds of manual assessment had poor agreement with the standardized automated assessment algorithm of LVDF. In conclusion, the presented automated decision support for evaluation of diastolic LV function by Doppler echocardiography is mainly based on current guidelines involving multiple parameters in combination. Incorporating age dependency aspects in our program (available for use at https://liu.se/en/research/left-ventricular-diastolic-function-decision-support) enhances the accuracy of the evaluation and reduces variability in evaluation of LVDF. The large inter-rater variation in classification in this study also underscores the usefulness of tools to support a standardized evaluation.
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| 10. |
- Allvin, Renée, 1956-, et al.
(författare)
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Confident but not theoretically grounded : experienced simulation educators’ perceptions of their own professional development
- 2017
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Ingår i: Advances in Medical Education and Practice. - Macclesfield : DOVE Medical Press Ltd.. - 1179-7258. ; :8, s. 99-108
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Tidskriftsartikel (refereegranskat)abstract
- Background: Medical simulation enables the design of learning activities for competency areas (eg, communication and leadership) identi ed as crucial for future health care professionals. Simulation educators and medical teachers follow different career paths, and their education backgrounds and teaching contexts may be very different in a simulation setting. Although they have a key role in facilitating learning, information on the continuing professional development (pedagogical development) of simulation educators is not available in the literature. Objectives: To explore changes in experienced simulation educators’ perceptions of their own teaching skills, practices, and understanding of teaching over time.Methods: A qualitative exploratory study. Fourteen experienced simulation educators partici- pated in individual open-ended interviews focusing on their development as simulation educators. Data were analyzed using an inductive thematic analysis. Results: Marked educator development was discerned over time, expressed mainly in an altered way of thinking and acting. Five themes were identi ed: shifting focus, from following to utilizing a structure, setting goals, application of technology, and alignment with profession. Being con dent in the role as an instructor seemed to constitute a foundation for the instructor’s pedagogical development.Conclusion: Experienced simulation educators’ pedagogical development was based on self- con dence in the educator role, and not on a deeper theoretical understanding of teaching and learning. This is the rst clue to gain increased understanding regarding educational level and possible education needs among simulation educators, and it might generate several lines of research for further studies.
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