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  • 1.
    Ahlsson, Anders
    et al.
    Örebro University, School of Health and Medical Sciences.
    Linde, Peter
    Rask, Peter
    Englund, Anders
    Örebro University, School of Health and Medical Sciences.
    Atrial function after epicardial microwave ablation in patients with atrial fibrillation2008In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 42, no 3, p. 192-201Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To study epicardial microwave ablation of concomitant atrial fibrillation and its effects on heart rhythm and atrial function during follow-up. DESIGN: The study included 20 open-heart surgery patients with concomitant atrial fibrillation. Transthoracic echocardiography with flow and tissue Doppler recordings was performed preoperatively and at 6 months postoperatively. Blood samples were obtained preoperatively and postoperatively for analysis of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and amino terminal precursor of brain natriuretic peptide (NT-proBNP). RESULTS: Fourteen of 19 patients (74%) were in sinus rhythm with no antiarrhythmic drugs at 12 months. All patients in sinus rhythm had preserved left and right atrial-filling waves through atrioventricular valves during atrial contraction. Tissue velocity echocardiography on patients in sinus rhythm showed preserved atrial wall velocities, atrial strain, and atrial strain rate. Levels of natriuretic peptides tended to decrease in patients with stable sinus rhythm at one year compared to patients in atrial fibrillation. CONCLUSIONS: Epicardial microwave ablation results in sinus rhythm in a majority of patients and seems to preserve atrial mechanical function

  • 2. Ahmed, Kamran
    et al.
    Rask, Peter
    Hurtig-Wennlöf, Anita
    Örebro University, School of Health and Medical Sciences.
    Serum apolipoproteins, apoB/apoA-I ratio and objectively measured physical activity in elderly2011In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 45, no 2, p. 105-111Article in journal (Refereed)
    Abstract [en]

    Objectives: Several studies have suggested that subjectively reported physical activity is associated with favorable apolipoproteins and apoB/apoA-I ratio but this association has not been studied much in elderly, and seldom with objective methods. The specific aim of the current study was to increase our understanding of the association between objectively measured physical activity, and apolipoproteins and apoB/apoA-I ratio in elderly subjects.

    Design: In a long-term follow-up of coronary artery bypass graft surgery patients, a total of 89 subjects (55?88 years old) were recruited. Peak oxygen uptake was measured by ergospirometry and physical activity by accelerometry. Subjects were divided into two groups based on their activity levels (i.e. more or less than 30 minutes of moderate activity per day).

    Results: Only 26% (23/89) of participants achieved the recommended 30 min/day of moderate intensity activity. Objectively measured physical activity was associated with higher apolipoprotein A-I levels and smaller apoB/apoAI ratio and lower body mass index, whereas no significant association with apolipoprotein B was observed.

    Conclusion: The significant association of objectively measured physical activity with favorable apolipoprotein A-I levels and a apoB/apoA-I ratio stresses the importance of being physically active.

  • 3.
    Hurtig-Wennlöf, Anita
    et al.
    Örebro University, School of Health and Medical Sciences.
    Ahlström, Christer
    Department of Biomedical Engineering, Linköping University, Linköping, Sweden; Biomedical Engineering, Örebro University Hospital, Örebro, Sweden.
    Egerlid, Rigmor
    Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Resare, Marie
    Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Ask, Per
    Department of Biomedical Engineering, Linköping University, Linköping, Sweden; Biomedical Engineering, Örebro University Hospital, Örebro, Sweden.
    Rask, Peter
    Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Heart sounds are altered by open cardiac surgery2009In: Experimental and clinical cardiology, ISSN 1205-6626, Vol. 14, no 2, p. 18-20Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND OBJECTIVE: Patients have reported that they perceive their own heart sounds differently after open cardiac surgery than before the surgery. The present study was designed to investigate whether changes in heart sounds can be quantitatively measured.

    METHOD: Heart sounds were recorded from 57 patients undergoing coronary artery bypass graft (CABG) surgery and from a control group of 10 subjects. The so-called Hjorth descriptors and the main frequency peak were compared before and after surgery to determine whether the characteristics of the heart sounds had changed.

    RESULTS: At a group level, the first heart sound was found to be significantly different after CABG surgery. Generally, the heart sounds shifted toward a lower frequency after surgery in the CABG group. No significant changes were found in the control group.

    CONCLUSION: Heart sounds are altered after CABG surgery. The changes are objectively quantifiable and may also be subjectively perceived by the patients.

  • 4.
    Karefylakis, Christos
    et al.
    Örebro University, School of Medical Sciences.
    Ariander, AnnaClara
    Rask, Peter
    Örebro University, School of Medical Sciences. Örebro University Hospital.
    Särnblad, Stefan
    Örebro University, School of Medical Sciences.
    Rask, Eva
    Region Örebro län, Örebro.
    Effect of Vitamin D supplementation on body composition in overweight men: A randomized controlled trial2017Conference paper (Refereed)
  • 5.
    Karefylakis, Christos
    et al.
    Örebro University, School of Medical Sciences.
    Särnblad, Stefan
    Örebro University, School of Medical Sciences.
    Ariander, Annaclara
    Örebro University, School of Medical Sciences.
    Ehlersson, Gustaf
    Örebro University, School of Medical Sciences.
    Rask, Eva
    Örebro University, School of Medical Sciences. Department of Endocrinology.
    Rask, Peter
    Örebro University Hospital. Örebro University, School of Medical Sciences.
    Effect of Vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men: A randomized controlled trialManuscript (preprint) (Other academic)
  • 6.
    Karefylakis, Christos
    et al.
    Department of Endocrinology, School of Medical Sciences, Örebro University, Örebro, Sweden.
    Särnblad, Stefan
    Örebro University, School of Medical Sciences. Department of Pediatrics.
    Ariander, Annaclara
    School of Medical Sciences, Örebro University, Örebro, Sweden.
    Ehlersson, Gustaf
    School of Medical Sciences, Örebro University, Örebro, Sweden.
    Rask, Eva
    Örebro University, School of Medical Sciences. Department of Endocrinology.
    Rask, Peter
    Örebro University Hospital. Örebro University, School of Medical Sciences. Department of Clinical Physiology.
    Effect of Vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men: a randomized controlled trial2018In: Endocrine (Basingstoke), ISSN 1355-008X, E-ISSN 1559-0100, Vol. 61, no 3, p. 388-397Article in journal (Refereed)
    Abstract [en]

    Purpose: Several observational studies have shown an association between vitamin D deficiency and non-skeletal major health issues including impaired cardiorespiratory fitness and adiposity. Only a few studies have examined the impact of vitamin D supplementation on these conditions and the results are ambiguous. The aim of this study was to examine the effect of vitamin D supplementation on body composition and cardiorespiratory fitness in overweight/obese men with vitamin D deficiency.

    Methods: This study was a prospective, placebo controlled, double blinded, randomized trial with a study period of 6 months. Forty overweight/obese men (BMI > 25 kg/m2) with vitamin D deficiency (25(OH)D ≤ 55 nmol/L) were randomized to receive either 2000 IU Cholecalciferol drops or the equivalent amount of drops of placebo. At baseline and follow up body composition and cardiorespiratory fitness were measured and blood samples were obtained. Body composition was measured using bioelectrical impedance analysis (BIA) and cardiorespiratory fitness using cardiopulmonary exercise test (CPET). The primary outcomes were changes in percentage body fat and in maximum oxygen uptake (VO2max).

    Results: No statistically significant difference between the placebo and the intervention group regarding changes in percentage body fat (p = 0.54) and VO2max (p = 0.90) was observed. Moreover, there was no statistically significant difference between the groups concerning changes in BMI (p = 0.26), maximum load (p = 0.89) and oxygen uptake at anaerobic threshold (AT) (p = 0.14).

    Conclusions: We conclude that treatment with 2000 IU/d vitamin D for 6 months does not impact body composition or maximum oxygen uptake in overweight/obese men with vitamin D deficiency.

  • 7.
    Kiotsekoglou, Anatoli
    et al.
    Örebro University Hospital. Örebro University, School of Medical Sciences. Department of Clinical Physiology, University Hospital of Örebro, Örebro, Sweden.
    Moggridge, James C.
    Department of Medical Physics and Bioengineering, University College Hospital, London, United Kingdom.
    Child, Anne H.
    Cardiovascular and Cell Sciences Research Institute, St George's, University of London, London, United Kingdom.
    Rask, Peter
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Clinical Physiology, University Hospital of Örebro, Örebro, Sweden.
    The role of advanced echocardiography and cardiovascular magnetic resonance in the assessment of myocardial function in Marfan syndrome-An update2017In: Echocardiography, ISSN 0742-2822, E-ISSN 1540-8175, Vol. 34, no 5, p. 760-767Article in journal (Refereed)
    Abstract [en]

    Cardiovascular assessment of patients with Marfan syndrome has normally focused on the aortic root and vascular manifestations of the disease due to the high risk of aortic dissection. Although primary myocardial impairment has long been suspected in these patients, the evidence has been controversial. Advanced echocardiography and cardiovascular magnetic resonance imaging have proven to be effective, accurate, and more sensitive in the detection of subtle cardiac dysfunction. The application of these techniques to Marfan syndrome over the last 10 years has made significant progress in demonstrating the presence of primary myocardial impairment in these patients, but further work is still required to obtain confirmatory molecular, pathophysiological, and prognostic clinical data. Phenotypic expression of the disease has prognostic value, also suggesting potential effective medical therapy.

  • 8.
    Lidén, Mats
    et al.
    Örebro University, School of Medical Sciences.
    Wodecki, Maciej
    Department of Clinical Physiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
    Thunberg, Per
    Örebro University, School of Medical Sciences. Department of Medical Physics.
    Rask, Peter
    Örebro University Hospital. Örebro University, School of Medical Sciences.
    Impact of Heart Rate on Flow Measurements in Aortic Regurgitation2017In: Journal of Heart Valve Disease, ISSN 0966-8519, E-ISSN 2053-2644, Vol. 26, no 5, p. 502-508, article id 4562Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Flow measurements using cardiac magnetic resonance imaging (CMRI) enable quantification of the stroke volume, regurgitant volume (RV) and regurgitant fraction (RF) in patients with aortic regurgitation (AR). These variables are used to assess the severity of the valve disease and for the timing of surgery. The aim of the study was to investigate the impact of an increased heart rate on measurement of the RV and RF in patients with AR.

    METHODS: Among 13 patients with known moderate or severe AR, regurgitant flow measurements, using phase-contrast cine magnetic resonance imaging, were obtained in the ascending aorta. Flow measurements were obtained at rest and at increased heart rates after intravenous administration of atropine.

    RESULTS: The mean heart rate was 61 beats per min at rest and 91 beats per min after atropine administration. The RV and RF were 52 ml and 35% at rest, respectively, and 34 ml (p <0.001) and 30% (p = 0.065) at increased heart rate, respectively.

    CONCLUSIONS: An increased heart rate leads to a decreased RV. The RF is more stable and may therefore be preferable for severity grading in AR.

  • 9.
    Loiske, Karin
    et al.
    Örebro University, School of Health and Medical Sciences. Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Waldenborg, Micael
    Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Fröbert, Ole
    Cardiology, Örebro University Hospital, Örebro, Sweden.
    Rask, Peter
    Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Emilsson, Kent
    Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Left and right ventricular systolic long-axis function and diastolic function in patients with takotsubo cardiomyopathy2011In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 31, no 3, p. 203-208Article in journal (Refereed)
    Abstract [en]

    Aims: Takotsubo cardiomyopathy is characterized by apical wall motion abnormalities without coronary stenosis. Limited information is available on the genesis of the underlying reversible contractile disorder. Our objective in this prospective study was to investigate biventricular changes in systolic long-axis function and diastolic parameters in the acute phase and after recovery.

    Methods and results: Thirteen consecutive patients were examined by echocardiography and coronary angiography at admission and again by echocardiography after 3 months. Amplitudes, systolic and diastolic velocities of the mitral and tricuspid annuli and conventional diastolic parameters were measured. Systolic long-axis shortening of the left ventricle (LV) and right ventricle (RV) improved from 9·6 ± 2·2 mm to 11·2 ± 1·9 mm (P = 0·02) and from 21·3 ± 3·6 mm to 24·1 ± 2·8 mm (P = 0·02), respectively. LV systolic, early and late diastolic velocities measured by pulsed-wave tissue Doppler also improved, while additional conventional diastolic parameters of the LV and RV diastolic function were unchanged.Conclusions: Takotsubo cardiomyopathy temporarily affects systolic LV and RV function, while most diastolic parameters remain unchanged

  • 10.
    Rask, Peter
    Umeå universitet, Klinisk fysiologi, Umeå, Sweden.
    Aortic stenosis: diagnostic use and hemodynamic effects of dipyridamole1995Doctoral thesis, comprehensive summary (Other academic)
  • 11.
    Thunberg, Per
    et al.
    Department of Biomedical Engineering, Örebro University Hospital, Örebro, Sweden.
    Emilsson, Kent
    Örebro University, School of Health and Medical Sciences. Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Rask, Peter
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Kähäri, Anders
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Estimation of ejection fraction and stroke volume using single- and biplane magnetic resonance imaging of the left cardiac ventricle2008In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 49, no 9, p. 1016-1023Article in journal (Other academic)
    Abstract [en]

    Background: In cardiac magnetic resonance imaging (MRI), left ventricular stroke volume (SV) and ejection fractions (EF) are occasionally calculated using single-plane and biplane ellipsoid models. In previous studies, the calculated SV and EF using single- and biplane ellipsoid models have been compared to reference values calculated from short-axis (SA) images. In these studies, however, it has been emphasized that through-plane motion of the basal SA images represents an important source of error, which may result in incorrect reference values.

    Purpose: To compare the calculated SV and EF using single-plane and biplane ellipsoid models with SV and EF calculated from SA images in which compensation was made for through-plane motion.

    Material and Methods: A group of 20 patients who underwent MRI examination were included in the study. SV and EF were calculated using the stack of SA images (which had been compensated for through-plane motion) and compared to the SV and EF calculated according to the single- and biplane ellipsoid models.

    Results: The mean difference between the single-plane model and the reference was -0.3±6.5 for EF and 7.2±17.1 ml for SV. Corresponding comparison between the biplane method and the reference resulted in a mean difference of 0.3±6.1 for EF and 11.8±14.9 ml for SV.

    Conclusion: The results from this study show that left ventricular EF can be adequately estimated using the single- and biplane ellipsoid models, while SV tends to be overestimated using both geometrical models

  • 12.
    Thunberg, Per
    et al.
    Department of Medical Physics, Örebro University Hospital, Örebro, Sweden.
    Emilsson, Kent
    Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Rask, Peter
    Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Kähäri, Anders
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Flow and peak velocity measurements in patients with aortic valve stenosis using phase contrast MR accelerated with k-t BLAST2012In: European Journal of Radiology, ISSN 0720-048X, E-ISSN 1872-7727, Vol. 81, no 9, p. 2203-2207Article in journal (Refereed)
    Abstract [en]

    Objective: To investigate the accuracy of velocity measurements in patients with aortic valve stenosis using phase contrast (PC) imaging accelerated with SENSE (Sensitivity Encoding) and k-t BLAST (Broad-use Linear Acquisition Speed-up Technique).

    Methods: Accelerated quantitative breath hold PC measurements, using SENSE and k-t BLAST, were performed in twelve patients whose aortic valve stenosis had been initially diagnosed using echocardiography. Stroke volume (SV) and peak velocity measurements were performed on each subject in three adjacent slices using both accelerating methods.

    Results: The peak velocities measured with PC MRI using SENSE were -8.0±9.5% lower (p<0.01) compared to the peak velocities measured with k-t BLAST and the correlation was r=0.83. The stroke volumes when using SENSE were slightly higher 0.4±17.1 ml compared to the SV obtained using k-t BLAST but the difference was not significant (p>0.05).

    Conclusions In this study higher peak velocities were measured in patients with aortic stenosis when combining k-t BLAST with PC MRI compared to PC MRI using SENSE. A probable explanation of this difference is the higher temporal resolution achieved in the k-t BLAST measurement. There was, however, no significant difference between calculated SV based on PC MRI using SENSE and k-t BLAST, respectively.

  • 13.
    Thunberg, Per
    et al.
    Örebro University, School of Health and Medical Sciences. Department of Biomedical Engineering.
    Emilsson, Kent
    Örebro University, School of Health and Medical Sciences. Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden.
    Rask, Peter
    Department of Clinical Physiology,, Örebro University Hospital, Örebro, Sweden.
    Kähäri, Anders
    Department of Radiology, Örebro University Hospital, Örebro, Sweden.
    Separating the left cardiac ventricle from the atrium in short axis MR images using the equation of the atrioventricular plane2008In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 28, no 4, p. 222-228Article in journal (Refereed)
    Abstract [en]

    Short axis (SA) images obtained from cardiac magnetic resonance imaging are used to advantage in the calculation of important clinical parameters such as the ejection fraction and stroke volume (SV). A prerequisite for these calculations is the separation of the left ventricle and the left atrium. When only using the information seen in the SA images this separation can be a source of error due to the through-plane motion of the basal part of the left ventricle. In this study a method is proposed where the separation of the left ventricle and the atrium is performed by identifying the intersections of the atrioventricular plane in the SA images. The equation of the atrioventricular plane was determined in both systole and diastole using long axis and four chamber image views. Stroke volumes were measured in 20 patients using SA images where the endocardium had been delineated. The SV obtained using the new method was compared with quantitative flow measurements and the conventional technique for calculation of SV from SA images, respectively. The agreement of SV was, according to Bland-Altman analysis, 2.0 ml (95% CI -12.0 to 15.9 ml) in comparison with the flow measurements and 2.2 ml (95% CI -9.2 to 13.6 ml) compared to the conventional method. Inter- and intra-observer variability, when using the new proposed method, was small. This study shows that the identification of the left atrioventricular plane in SA images can be used in the separation of the left atrium and ventricle.

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