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- Ingvarsson, Annika, et al.
(författare)
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Normal Reference Ranges for Transthoracic Echocardiography Following Heart Transplantation
- 2018
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 0894-7317. ; 31:3, s. 349-360
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Tidskriftsartikel (refereegranskat)abstract
- Background: Heart function following heart transplantation (HTx) is influenced by numerous factors. It is typically evaluated using transthoracic echocardiography, but reference values are currently unavailable for this context. The primary aim of the present study was to derive echocardiographic reference values for chamber size and function, including cardiac mechanics, in clinically stable HTx patients. Methods: The study enrolled 124 healthy HTx patients examined prospectively. Patients underwent comprehensive two-dimensional echocardiographic examinations according to contemporary guidelines. Results were compared with recognized reference values for healthy subjects. Results: Compared with guidelines, larger atrial dimensions were seen in HTx patients. Left ventricular (LV) diastolic volume was smaller, and LV wall thickness was increased. With respect to LV function, both ejection fraction (62 ± 7%, P < .01) and global longitudinal strain (-16.5 ± 3.3%, P < .0001) were lower. All measures of right ventricular (RV) size were greater than reference values (P < .0001), and all measures of RV function were reduced (tricuspid annular plane systolic excursion 15 ± 4 mm [. P < .0001], RV systolic tissue Doppler velocity 10 ± 6 cm/sec [. P < .0001], fractional area change 40 ± 8% [. P < .0001], and RV free wall strain -16.9 ± 4.2% [. P < .0001]). Ejection fraction and LV global longitudinal strain were significantly lower in patients with previous rejection. Conclusion: The findings of this study indicate that the distribution of routinely used echocardiographic measures differs between stable HTx patients and healthy subjects. In particular, markedly larger RV and atrial volumes and mild reductions in both LV and RV longitudinal strain were evident. The observed differences could be clinically relevant in the assessment of HTx patients, and specific reference values should be applied in this context.
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- Werther Evaldsson, A., et al.
(författare)
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Echocardiographic right ventricular strain from multiple apical views is superior for assessment of right ventricular systolic function
- 2019
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961. ; 39:2, s. 168-176
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Tidskriftsartikel (refereegranskat)abstract
- Background: Right ventricular (RV) systolic function is an important determinant of outcome in patients with pulmonary hypertension (PH). Conventional echocardiographic measures of RV are mainly based on longitudinal contractility. Recently, measurement of RV global longitudinal strain derived from multiple windows (RVGLS) has emerged as an option but has not been well evaluated. The aim of the present study was to evaluate which echocardiographic RV function parameter correlates best with RV ejection fraction derived from cardiac magnetic resonance imaging (RVEFCMR). Methods and results: Fifty-five patients evaluated for PH underwent RV assessment with echocardiography and CMR. Conventional echocardiographic parameters of RV function including tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (S′), RV fractional area change (RVFAC) and RV index of myocardial performance (RIMP). RVGLS was measured from three separate apical views using a 17-segment model and strain from the lateral free wall was calculated separately (RVfree). The study included 55 patients, whereas assessment of RVGLS could be obtained in 29 patients. The Pearson correlation coefficient with RVEFCMR was strong for RVGLS (r = 0·814, P<0·001) and RVfree (r = 0·778, P<0·001), modest for RVFAC (r = 0·681, P<0·001), TAPSE (r = 0·592, P<0·001) and RIMP (r=−0·521, P<0·01), and weak for S′ (r = 0·385, P<0·01). Conclusion: The echocardiographic RV measures, RVGLS and RVfree correlated well with RVEFCMR, whereas correlation with TAPSE, RIMP and S′ was unsatisfactory. Our findings suggest that RVGLS and RVfree are the preferred echocardiographic methods for clinical practice. RVfree is easiest to perform but RVGLS could provide incremental value in selected patients.
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| 5. |
- Ingvarsson, Annika, et al.
(författare)
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Impact of bridging with left ventricular assist device on right ventricular function following heart transplantation.
- 2022
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Ingår i: ESC heart failure. - : Wiley. - 2055-5822. ; 9:3, s. 1864-1874
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Tidskriftsartikel (refereegranskat)abstract
- Patients awaiting orthotopic heart transplantation (OHT) can be bridged utilizing a left ventricular assist device (LVAD) that reduces left ventricular filling pressures, decreases pulmonary artery wedge pressure, and maintains adequate cardiac output. This study set out to examine the poorly investigated area of if and how pre-treatment with LVAD impacts right ventricular (RV) function following OHT.We prospectively evaluated 59 (LVAD n=20) consecutive OHT patients. Transthoracic echocardiography (TTE) was performed in conjunction with right heart catheterization (RHC) at 1, 6, and 12months after OHT. RV function TTE-parameters included tricuspid annular plane systolic excursion (TAPSE), systolic tissue velocity (S'), fractional area change, two-dimensional RV global longitudinal strain and longitudinal strain from the RV lateral wall (RVfree). At 1month after OHT, the LVAD group had significantly better longitudinal RV function than the non-LVAD group: TAPSE (15±3mm vs. 12±2mm, P<0.001), RV global longitudinal strain (-19.8±2.1% vs. -14.3±2.8%, P<0.001), and RVfree (-19.8±2.3% vs. -14.1±2.9%, P<0.001). At this time point, pulmonary vascular resistance (PVR) was also lower [1.2±0.4 Wood Units (WU) vs. 1.6±0.6 WU, P<0.05] in the LVAD group compared with the non-LVAD group. At 6 and 12months, no difference was detected in any of the TTE and RHC measured parameters between the two groups. Between 1 and 12months, all parameters of RV function improved significantly in the non-LVAD group but remained unaltered in the LVAD group.Our results indicate that pre-treatment with LVAD decreases PVR and is associated with significantly better RV function early following OHT. During the first year following transplantation, RV function progressively improved in the non-LVAD group such that at 6 and 12months, no difference in RV function was detected between the groups.
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| 6. |
- Ingvarsson, Annika, et al.
(författare)
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Impact of gender on echocardiographic characteristics in heart transplant recipients
- 2019
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 39:4, s. 246-254
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Assessment following heart transplantation (HTx) is routinely performed using transthoracic echocardiography. Differences in long-term mortality following HTx related to donor-recipient matching have been reported, but effects of gender on cardiac size and function are not well studied. The aims of this study were to evaluate differences in echocardiographic characteristics of HTx recipients defined by gender. Methods and results: The study prospectively enrolled 123 (n = 34 female) HTx recipients of which 23 recipients was donor-recipient gender mismatched. Patients were examined with 2-dimensional echocardiography using Philips iE33 ultrasound system. Data were analysed across strata based on recipient gender and gender mismatch. Male recipients had larger left ventricular (LV) mass, thicker septal wall (P<0·001) and larger absolute LV volumes (P<0·001). Mean LV ejection fraction (EF) was higher in females (P<0·05), but no differences in conventional parameters of right ventricular (RV) function were found. Ventricular strain was higher in females than in males: LV global longitudinal strain (P<0·01), RV global longitudinal strain (P<0·05) and RV lateral free wall (P<0·05). The male group receiving a female donor heart had comparable EF and strain parameters to the female group receiving a gender-matched heart. Conclusion: We found that female recipient gender was associated with smaller chamber size, higher LV EF and better LV and RV longitudinal strain. Gender-mismatched male recipients appeared to exhibit function parameters similar to gender-matched female recipients. Our results indicate that the gender aspect, analogous to current reference guidelines in general population, should be taken into consideration when examining patients post-HTx.
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| 7. |
- Johnsson, Filip, 1960, et al.
(författare)
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An experimental study of in-furnace processes and dynamic behaviour of a 235 MWe CFB boiler
- 2004
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Ingår i: VGB PowerTech. - 1435-3199. ; 84:3, s. 82-87
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Tidskriftsartikel (refereegranskat)abstract
- In a project funded by the 5th Framework Programme of the European Union, a 235 MWe Circulating Fluidized Bed (CFB) boiler is investigated with respect to in-furnace processes and dynamic response to load changes. The purpose of the project is to assess the insufficiently known features of large-scale CFB boilers. The furnace of the boiler has a cross-section of 21 x 10 meters and a height of 44 meters. The boiler is located in Turow, Poland, and is operated on a local brown coal.The project is unique in that several measurement ports were opened in the walls of the large CFB furnace for measurements in various locations inside the furnace. Also, a number of techniques were employed with new probes developed for this type of measurements to form a basis for studies of hydrodynamic processes as well as local variations in gas components (such as O2, CO, THC) and solid bed materials. The paper describes the measurement techniques and provides examples of results obtained from the in-situ measurements and from the dynamic response study.
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| 10. |
- Knöbig, T, et al.
(författare)
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Are measurements in small-scale combustors representative of the performance of large-scale combustors with circulating fluidized bed?
- 1997
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Ingår i: VDI Berichte 1314: Wirbelschichtfeurungen: Erfahrungen und Perspektiven. - 3180913142 ; 1314, s. 281-296
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Comparative combustion experiments were performed in an industrial-scale combustor at the Chalmers University of Technology and in a lab-scale facility at the Technical University of Hamburg-Harburg. A comparison between the axial profiles of the concentrations of O2, CO NO, N2O and NH3 along the riser height, which were obtained during combustion of wood, peat and coal, shows basic similarity, which indicates that lab-scale combustors of suitable dimensions may be a valuable tool for the investigation of combustion phenomena. However, some significant deviations caused by three-dimensional effects in the large-scale combustor and indicate the limitations of small-scale experiments.
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