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- Ahlsson, Anders, et al.
(author)
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Atrial function after epicardial microwave ablation in patients with atrial fibrillation
- 2008
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In: Scandinavian Cardiovascular Journal. - : Taylor & Francis. - 1401-7431 .- 1651-2006. ; 42:3, s. 192-201
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Journal article (peer-reviewed)abstract
- 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
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| 2. |
- Ahlström, Christer, 1977-, et al.
(author)
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Assessment of Suspected Aortic Stenosis by Auto Mutual Information Analysis of Murmurs
- 2007
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In: Engineering in Medicine and Biology Society, 2007. EMBS 2007. - 9781424407873 ; , s. 1945-1948
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Conference paper (peer-reviewed)abstract
- Mild sclerotic thickening of the aortic valve affects 25% of the population, and the condition causes aortic valve stenosis (AS) in 2% of adults above 65 years. Echocardiography is today the clinical standard for assessing AS. However, a cost effective and uncomplicated technique that can be used for decision support in the primary health care would be of great value. In this study, recorded phonocardiographic signals were analyzed using the first local minimum of the auto mutual information (AMI) function. The AMI method measures the complexity in the sound signal, which is related to the amount of turbulence in the blood flow and thus to the severity of the stenosis. Two previously developed phonocardiographic methods for assessing AS severity were used for comparison, the murmur energy ratio and the sound spectral averaging technique. Twenty-nine patients with suspected AS were examined with Doppler echocardiography. The aortic jet velocity was used as a reference of AS severity, and it was found to correlate with the AMI method, the murmur energy ratio and the sound spectral averaging technique with the correlation coefficient R = 0.82, R = 0.73 and R = 0.76, respectively.
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| 3. |
- Ahlström, Christer, et al.
(author)
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Feature Extraction for Systolic Heart Murmur Classification
- 2006
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In: Annals of Biomedical Engineering. - : Springer Science and Business Media LLC. - 0090-6964 .- 1573-9686. ; 34:11, s. 1666-1677
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Journal article (peer-reviewed)abstract
- Heart murmurs are often the first signs of pathological changes of the heart valves, and they are usually found during auscultation in the primary health care. Distinguishing a pathological murmur from a physiological murmur is however difficult, why an “intelligent stethoscope” with decision support abilities would be of great value. Phonocardiographic signals were acquired from 36 patients with aortic valve stenosis, mitral insufficiency or physiological murmurs, and the data were analyzed with the aim to find a suitable feature subset for automatic classification of heart murmurs. Techniques such as Shannon energy, wavelets, fractal dimensions and recurrence quantification analysis were used to extract 207 features. 157 of these features have not previously been used in heart murmur classification. A multi-domain subset consisting of 14, both old and new, features was derived using Pudil’s sequential floating forward selection (SFFS) method. This subset was compared with several single domain feature sets. Using neural network classification, the selected multi-domain subset gave the best results; 86% correct classifications compared to 68% for the first runner-up. In conclusion, the derived feature set was superior to the comparative sets, and seems rather robust to noisy data.
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| 4. |
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| 5. |
- Karefylakis, Christos, et al.
(author)
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Effect of Vitamin D supplementation on body composition and cardiorespiratory fitness in overweight men : a randomized controlled trial
- 2018
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In: Endocrine. - : Humana Press. - 1355-008X .- 1559-0100. ; 61:3, s. 388-397
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Journal article (peer-reviewed)abstract
- 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.
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| 6. |
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| 7. |
- Senn, Pascal, et al.
(author)
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NANOCI-Nanotechnology Based Cochlear Implant With Gapless Interface to Auditory Neurons
- 2017
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In: Otology and Neurotology. - 1531-7129 .- 1537-4505. ; 38:8, s. E224-E231
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Journal article (peer-reviewed)abstract
- Cochlear implants (CI) restore functional hearing in the majority of deaf patients. Despite the tremendous success of these devices, some limitations remain. The bottleneck for optimal electrical stimulation with CI is caused by the anatomical gap between the electrode array and the auditory neurons in the inner ear. As a consequence, current devices are limited through 1) low frequency resolution, hence suboptimal sound quality and 2), large stimulation currents, hence high energy consumption (responsible for significant battery costs and for impeding the development of fully implantable systems). A recently completed, multinational and interdisciplinary project called NANOCI aimed at overcoming current limitations by creating a gapless interface between auditory nerve fibers and the cochlear implant electrode array. This ambitious goal was achieved in vivo by neurotrophin-induced attraction of neurites through an intra-cochlear gel-nanomatrix onto a modified nanoCI electrode array located in the scala tympani of deafened guinea pigs. Functionally, the gapless interface led to lower stimulation thresholds and a larger dynamic range in vivo, and to reduced stimulation energy requirement (up to fivefold) in an in vitro model using auditory neurons cultured on multi-electrode arrays. In conclusion, the NANOCI project yielded proof of concept that a gapless interface between auditory neurons and cochlear implant electrode arrays is feasible. These findings may be of relevance for the development of future CI systems with better sound quality and performance and lower energy consumption. The present overview/review paper summarizes the NANOCI project history and highlights achievements of the individual work packages.
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| 8. |
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| 9. |
- Ahmed, Kamran, et al.
(author)
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Serum apolipoproteins, apoB/apoA-I ratio and objectively measured physical activity in elderly
- 2011
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In: Scandinavian Cardiovascular Journal. - : Informa Healthcare. - 1401-7431 .- 1651-2006. ; 45:2, s. 105-111
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Journal article (peer-reviewed)abstract
- 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.
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| 10. |
- Alme, Tomas Nordheim, et al.
(author)
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Chronic fatigue syndromes: real illnesses that people can recover from
- 2023
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In: Scandinavian Journal of Primary Health Care. - : TAYLOR & FRANCIS LTD. - 0281-3432 .- 1502-7724. ; 41:4, s. 372-376
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Journal article (peer-reviewed)abstract
- The Oslo Chronic Fatigue Consortium consists of researchers and clinicians who question the current narrative that chronic fatigue syndromes, including post-covid conditions, are incurable diseases. Instead, we propose an alternative view, based on research, which offers more hope to patients. Whilst we regard the symptoms of these conditions as real, we propose that they are more likely to reflect the brains response to a range of biological, psychological, and social factors, rather than a specific disease process. Possible causes include persistent activation of the neurobiological stress response, accompanied by associated changes in immunological, hormonal, cognitive and behavioural domains. We further propose that the symptoms are more likely to persist if they are perceived as threatening, and all activities that are perceived to worsen them are avoided. We also question the idea that the best way to cope with the illness is by prolonged rest, social isolation, and sensory deprivation.Instead, we propose that recovery is often possible if patients are helped to adopt a less threatening understanding of their symptoms and are supported in a gradual return to normal activities. Finally, we call for a much more open and constructive dialogue about these conditions. This dialogue should include a wider range of views, including those of patients who have recovered from them.
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