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  • 1. Abdukalikova, Anara
    et al.
    Kleyko, Denis
    Osipov, Evgeny
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Detection of Atrial Fibrillation From Short ECGs: Minimalistic Complexity Analysis for Feature-Based Classifiers2018In: 2018 Computing in Cardiology Conference (CinC), IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    In order to facilitate data-driven solutions for early detection of atrial fibrillation (AF), the 2017 CinC conference challenge was devoted to automatic AF classification based on short ECG recordings. The proposed solutions concentrated on maximizing the classifiers F-1 score, whereas the complexity of the classifiers was not considered. However, we argue that this must be addressed as complexity places restrictions on the applicability of inexpensive devices for AF monitoring outside hospitals. Therefore, this study investigates the feasibility of complexity reduction by analyzing one of the solutions presented for the challenge.

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  • 2. Abrahamsson, Niclas
    et al.
    Borjesson, Joey Lau
    Sundbom, Magnus
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Karlsson, F. Anders
    Eriksson, Jan W.
    Gastric Bypass Reduces Symptoms and Hormonal Responses in Hypoglycemia2016In: Diabetes, ISSN 0012-1797, E-ISSN 1939-327X, Vol. 65, no 9, p. 2667-2675Article in journal (Refereed)
    Abstract [en]

    Gastric bypass (GBP) surgery, one of the most common bariatric procedures, induces weight loss and metabolic effects. The mechanisms are not fully understood, but reduced food intake and effects on gastrointestinal hormones are thought to contribute. We recently observed that GBP patients have lowered glucose levels and frequent asymptomatic hypoglycemic episodes. Here, we subjected patients before and after undergoing GBP surgery to hypoglycemia and examined symptoms and hormonal and autonomic nerve responses. Twelve obese patients without diabetes (8 women, mean age 43.1 years [SD 10.8] and BMI 40.6 kg/m(2) [SD 3.1]) were examined before and 23 weeks (range 19-25) after GBP surgery with hyperinsulinemic-hypoglycemic clamp (stepwise to plasma glucose 2.7 mmol/L). The mean change in Edinburgh Hypoglycemia Score during clamp was attenuated from 10.7 (6.4) before surgery to 5.2 (4.9) after surgery. There were also marked postsurgery reductions in levels of glucagon, cortisol, and catecholamine and the sympathetic nerve responses to hypoglycemia. In addition, growth hormone displayed a delayed response but to a higher peak level. Levels of glucagon-like peptide 1 and gastric inhibitory polypeptide rose during hypoglycemia but rose less postsurgery compared with presurgery. Thus, GBP surgery causes a resetting of glucose homeostasis, which reduces symptoms and neurohormonal responses to hypoglycemia. Further studies should address the underlying mechanisms as well as their impact on the overall metabolic effects of GBP surgery.

  • 3.
    Albano, Amanda
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Gustavsson, Sandra
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lindqvist, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Grönlund, Christer
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Echocardio-variability - Low and high frequency beat-to-beat variability in echocardiographic signals2013In: Computing in Cardiology 2013, 2013, p. 767-770, article id 6713490Conference paper (Refereed)
    Abstract [en]

    Measurement signals originating from the cardiovascular system are known to comprise oscillating components and beat-to-beat variability, e.g., heart-rate variability and blood pressure variability. In clinical echocardiographic procedures, typically only a few cardiac cycles are acquired. This pilot study analyses the beat-to-beat variability of echocardiographic variables (echocardio-variability) in minute long acquisitions. 

  • 4.
    Alenius Dahlqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hörnsten, Rolf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Handheld ECG in analysis of arrhythmia and heart rate variability in children with Fontan circulation2014In: Journal of Electrocardiology, ISSN 0022-0736, E-ISSN 1532-8430, Vol. 47, no 3, p. 374-382Article in journal (Refereed)
    Abstract [en]

    Background: Our aim was to evaluate the intermittent use of a handheld ECG system for detecting silent arrhythmias and cardiac autonomic dysfunction in children with univentricular hearts. Methods: Twenty-seven patients performed intermittent ECG recordings with handheld devices during a 14-day period. A manual arrhythmia analysis was performed. We analyzed heart rate variability (HRV) using scatter plots of all interbeat intervals (Poincare plots) from the total observation period. Reference values of HRV indices were determined from Holter-ECGs in 41 healthy children. Results: One asymptomatic patient had frequent ventricular extra systoles. Another patient had episodes with supraventricular tachycardia (with concomitant palpitations). Seven patients showed reduced HRV. Conclusions: Asymptomatic arrhythmia was detected in one patient. The proposed method for pooling of intermittent recordings from handheld or similar devices may be used for detection of arrhythmias as well as for cardiac autonomic dysfunction.

  • 5.
    Alenius Dahlqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hörnsten, Rolf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Strömvall-Larsson, Eva
    Division of Cardiology, Department of Paediatrics, Sahlgrenska University Hospital/Queen Silvia Children’s Hospital, Göteborg University, Göteborg, Sweden.
    Berggren, Håkan
    Division of Cardiothoracic Surgery, Department of Paediatrics, Sahlgrenska University Hospital/Queen Silvia Children’s Hospital, Göteborg University, Göteborg, Sweden.
    Hanseus, Katarina
    Department of Paediatrics, Children’s Hospital, Lund University Hospital, Lund, Sweden.
    Johansson, Sune
    Paediatric Cardiac Surgical Unit, Children’s Hospital, Lund University Hospital, Lund, Sweden.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Heart rate variability in children with fontan circulation: lateral tunnel and extracardiac conduit2012In: Pediatric Cardiology, ISSN 0172-0643, E-ISSN 1432-1971, Vol. 33, no 2, p. 307-315Article in journal (Refereed)
    Abstract [en]

    The technique in Fontan surgery has developed from the lateral tunnel (LT) toward the extracardiac conduit (EC) used to reduce long-term complications such as atrial arrhythmia and sinus node dysfunction. Heart rate variability (HRV) examines cardiac nervous activity controlling the sinus node. This study aimed to investigate HRV in a cohort of children with univentricular hearts, focusing on the relation between HRV and surgical procedure. For 112 children with Fontan circulation, HRV was analyzed using power spectral analysis. Spectral power was determined in three regions: very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) regions. Patients were compared with 66 healthy controls subject. Patients with LT were compared with patients who had EC. The children with Fontan circulation showed a significantly reduced HRV including total power (P < 0.0001), VLF (P < 0.0001), LF (P < 0.0001), and HF (P = 0.001) compared with the control subjects. The LT and EC patients did not differ significantly. Reduced HRV was found in both the LT and EC patients. In terms of HRV reduction, EC was not superior to LT.

  • 6.
    Alenius Dahlqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Sunnegårdh, Jan
    Department of Cardiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
    Hanséus, Katarina
    Department of Clinical Sciences Lund, Children Heart Center, Skåne University Hospital, Lund University, Lund, Sweden.
    Strömvall Larsson, Eva
    Department of Cardiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
    Nygren, Anders
    Department of Cardiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
    Dalén, Magnus
    Department of Molecular Medicine and Surgery, Department of Cardiac Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
    Berggren, Håkan
    Department of Pediatric Cardiac Surgery, Children's Heart Center, The Queen Silvia Children's Hospital, Gothenburg , Sweden.
    Johansson Ramgren, Jens
    Department of Pediatric Cardiac Surgery, Children´s Heart Center, Skånes University Hospital Lund, Sweden.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Pacemaker treatment after Fontan surgery: a Swedish national study2019In: Congenital Heart Disease, ISSN 1747-079X, E-ISSN 1747-0803, Vol. 14, no 4, p. 582-589Article in journal (Refereed)
    Abstract [en]

    Objective: Fontan surgery is performed in children with univentricular heart defects. Previous data regarding permanent pacemaker implantation frequency and indications in Fontan patients are limited and conflicting. We examined the prevalence of and risk factors for pacemaker treatment in a consecutive national cohort of patients after Fontan surgery in Sweden.

    Methods: We retrospectively reviewed all Swedish patients who underwent Fontan surgery from 1982 to 2017 (n = 599).

    Results: After a mean follow‐up of 12.2 years, 13% (78/599) of the patients with Fontan circulation had received pacemakers. Patients operated with the extracardiac conduit (EC) type of total cavopulmonary connection had a significantly lower prevalence of pacemaker implantation (6%) than patients with lateral tunnel (LT; 17%). Mortality did not differ between patients with (8%) and without pacemaker (5%). The most common pacemaker indication was sinus node dysfunction (SND) (64%). Pacemaker implantation due to SND was less common among patients with EC. Pacemaker implantation was significantly more common in patients with mitral atresia (MA; 44%), double outlet right ventricle (DORV; 24%) and double inlet left ventricle (DILV; 20%). In contrast, patients with pulmonary atresia with intact ventricular septum and hypoplastic left heart syndrome were significantly less likely to receive a pacemaker (3% and 6%, respectively).

    Conclusions: Thirteen percent of Fontan patients received a permanent pacemaker, most frequently due to SND. EC was associated with a significantly lower prevalence of pacemaker than LT. Permanent pacemaker was more common in patients with MA, DORV, and DILV.

  • 7.
    Alenius Dahlqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hanséus, Katarina
    Department of Clinical Sciences Lund, Children Heart Centre, Skåne University Hospital, Lund University, Lund, Sweden.
    Strömvall Larsson, Eva
    Department of Cardiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
    Johansson Ramgren, Jens
    Department of Pediatric Cardiac Surgery, Children´s Heart Center, Skånes University Hospital Lund, Sweden.
    Berggren, Håkan
    Department of Pediatric Cardiac Surgery, Children's Heart Center, The Queen Silvia Children's Hospital, Gothenburg, Sweden.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Changes in Heart Rate and Heart Rate Variability During Surgical Stages to Completed Fontan Circulation2021In: Pediatric Cardiology, ISSN 0172-0643, E-ISSN 1432-1971, Vol. 42, no 5, p. 1162-1169Article in journal (Refereed)
    Abstract [en]

    Arrhythmia is related to heart rate variability (HRV), which reflects the autonomic nervous regulation of the heart. We hypothesized that autonomic nervous ganglia, located at the junction of the superior vena cava’s entrance to the heart, may be affected during the bidirectional Glenn procedure (BDG), resulting in reduced HRV. We aimed to investigate changes in heart rate and HRV in a cohort of children with univentricular heart defects, undergoing stepwise surgery towards total cavopulmonary connection (TCPC), and compare these results with healthy controls. Twenty four hours Holter-ECG recordings were obtained before BDG (n = 47), after BDG (n = 47), and after total cavopulmonary connection (TCPC) (n = 45) in patients and in 38 healthy controls. HRV was analyzed by spectral and Poincaré methods. Age-related z scores were calculated and compared using linear mixed effects modeling. Total HRV was significantly lower in patients before BDG when compared to healthy controls. The mean heart rate was significantly reduced in patients after BDG compared to before BDG. Compared to healthy controls, patients operated with BDG had significantly reduced heart rate and reduced total HRV. Patients with TCPC showed reduced heart rate and HRV compared with healthy controls. In patients after TCPC, total HRV was decreased compared to before TCPC. Heart rate was reduced after BDG procedure, and further reductions of HRV were seen post-TCPC. Our results indicate that autonomic regulation of cardiac rhythm is affected both after BDG and again after TCPC. This may be reflected as, and contribute to, postoperative arrhythmic events.

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  • 8.
    Alenius Dahlqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Hanséus, Katarina
    Department of Clinical Sciences Lund, Children Heart Centre, Skåne University Hospital, Lund University, Lund, Sweden.
    Strömvall Larsson, Eva
    Department of Cardiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
    Nygren, Anders
    Department of Cardiology, The Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
    Eliasson, Håkan
    Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Sinus node dysfunction in patients with Fontan circulation: could heart rate variability be a predictor for pacemaker implantation?Manuscript (preprint) (Other academic)
  • 9.
    Alenius Dahlqvist, Jenny
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hanséus, Katarina
    Strömvall-Larsson, Eva
    Nygren, Anders
    Eliasson, Håkan
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Sinus node dysfunction in patients with Fontan circulation: could heart rate variability be a predictor for pacemaker implantation?2019In: Pediatric Cardiology, ISSN 0172-0643, E-ISSN 1432-1971, Vol. 40, no 4, p. 685-693Article in journal (Refereed)
    Abstract [en]

    Sinus node dysfunction (SND) causes significant morbidity in patients after Fontan surgery. Heart rate variability (HRV) reflects the autonomic regulation of the heart, and changes in HRV have been associated with SND in adults. We aimed to study whether changes in HRV could be detected in 24-h electrocardiographic (ECG) recordings in Fontan patients with SND. We compared HRV results from two patient groups; patients with Fontan circulation who later required a pacemaker due to severe SND (n = 12) and patients with Fontan circulation and SND, without indication for pacemaker treatment (n = 11), with two control groups; patients with Fontan circulation without SND (n = 90) and healthy controls (n = 66). The Poincare plot index SD2 (representing changes in heart rate over 24-h) and the very low-frequency (VLF) HRV component were significantly higher in both SND groups, both compared with healthy controls and patients with Fontan circulation without SND. In SND patients with pacemakers, SD2 and VLF were slightly reduced compared to SND patients without pacemaker (p = 0.06). In conclusion, in Fontan patients with SND the HRV is significantly higher compared to healthy controls and Fontan patients without SND. However, in patients with severe SND requiring pacemaker, SD2 and VLF tended to be lower than in patients with SND without pacemaker, which could indicate a reduced diurnal HRV in addition to the severe bradycardia. This is a small study, but our results indicate that HRV analysis might be a useful method in the follow-up of Fontan patients regarding development of SND.

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  • 10. Almby, K. E.
    et al.
    Abrahamsson, N.
    Lundqvist, M. H.
    Hammar, U.
    Thombare, K.
    Panagiotou, A.
    Karlsson, F. A.
    Sundbom, M.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Eriksson, J. W.
    Effects of GLP-1 receptor activation on counterregulatory responses during hypoglycaemia after gastric bypass surgery: no evidence for GLP-1 as a counterregulatory hormone2019In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 62, p. S416-S416Article in journal (Other academic)
  • 11. Almby, Kristina E.
    et al.
    Abrahamsson, Niclas
    Lundqvist, Martin H.
    Hammara, Ulf
    Thombare, Ketan
    Panagiotou, Amalia
    Karisson, F. Anders
    Sundbom, Magnus
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Eriksson, Jan W.
    Effects of GLP-1 on counter-regulatory responses during hypoglycemia after GBP surgery2019In: European Journal of Endocrinology, ISSN 0804-4643, E-ISSN 1479-683X, Vol. 181, no 2, p. 161-171Article in journal (Refereed)
    Abstract [en]

    Objectives: The aim of the study was to explore the role of GLP-1 receptor activation on the counter-regulation and symptoms of hypoglycemia in subjects who have undergone gastric bypass surgery (GBP).

    Design: Experimental hyperinsulinemic–hypoglycemic clamp study.

    Methods: Twelve post-GBP subjects participated in a randomized cross-over study with two hyperinsulinemic, hypoglycemic clamps (glucose nadir 2.7 mmol/L) performed on separate days with concomitant infusions of the GLP-1 analog exenatide or with saline, respectively. Continuous measurements of metabolites and counter-regulatory hormones as well as assessments of heart rate variability and symptoms of hypoglycemia were performed throughout the clamps.

    Results: No effect of GLP-1 receptor activation on counter-regulatory hormones (glucagon, catecholamines, cortisol, GH) or glucose infusion rate was seen, but we found indications of a downregulation of the sympathetic relative to the parasympathetic nerve activity, as reflected in heart rate variability. No significant differences in symptom of hypoglycemia were observed.

    Conclusions/interpretation: Short-term exposure to a GLP-1 receptor agonist does not seem to impact the counter-regulatory hormonal and metabolic responses in post-GBP subjects during hypoglycemic conditions, suggesting that the improvement in symptomatic hypoglycemia post-GBP seen following treatment with GLP-1 receptor agonists may be mediated by mechanism not directly involved in counter-regulation.

  • 12.
    Almby, Kristina E.
    et al.
    Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Katsogiannos, Petros
    Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Pereira, Maria J.
    Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Anders Karlsson, F.
    Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Sundbom, Magnus
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Kamble, Prasad G.
    Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Eriksson, Jan W.
    Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Time course of metabolic, neuroendocrine, and adipose effects during 2 years of follow-up after gastric bypass in patients with type 2 diabetes2021In: Journal of Clinical Endocrinology and Metabolism, ISSN 0021-972X, E-ISSN 1945-7197, Vol. 106, no 10, p. E4049-E4061Article in journal (Refereed)
    Abstract [en]

    Context: Roux-en-Y gastric bypass surgery (RYGB) markedly improves glycemia in patients with type 2 diabetes (T2D), but underlying mechanisms and changes over time are incompletely understood.

    Objective: Integrated assessment of neuroendocrine and metabolic changes over time inT2D patients undergoing RYGB.

    Design and Setting: Follow-up of single-center randomized study.

    Patients: Thirteen patients with obesity andT2D compared to 22 healthy subjects.

    Interventions: Blood chemistry, adipose biopsies, and heart rate variability were obtained before and 4, 24, and 104 weeks post-RYGB.

    Results: After RYGB, glucose-lowering drugs were discontinued and hemoglobin A1c fell from mean 55 to 41 mmol/mol by 104 weeks (P < 0.001). At 4 weeks, morning cortisol (P < 0.05) and adrenocorticotropin (P = 0.09) were reduced by 20%. Parasympathetic nerve activity (heart rate variability derived) increased at 4 weeks (P < 0.05) and peaked at 24 weeks (P < 0.01). C-reactive protein (CRP) and white blood cells were rapidly reduced (P < 0.01). At 104 weeks, basal and insulin-stimulated adipocyte glucose uptake increased by 3-fold vs baseline and expression of genes involved in glucose transport, fatty acid oxidation, and adipogenesis was upregulated (P < 0.01). Adipocyte volume was reduced by 4 weeks and more markedly at 104 weeks, by about 40% vs baseline (P < 0.01).

    Conclusions: We propose this order of events: (1) rapid glucose lowering (days); (2) attenuated cortisol axis activity and inflammation and increased parasympathetic tone (weeks); and (3) body fat and weight loss, increased adipose glucose uptake, and whole-body insulin sensitivity (months-years; similar to healthy controls).Thus, neuroendocrine pathways can partly mediate early glycemic improvement after RYGB, and adipose factors may promote long-term insulin sensitivity and normoglycemia.

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  • 13.
    Almby, Kristina E.
    et al.
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Lundqvist, Martin H.
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Abrahamsson, Niclas
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Kvernby, Sofia
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Fahlström, Markus
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Pereira, Maria J.
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Gingnell, Malin
    Department of Neurosciences and Department of Psychology, Uppsala University, Uppsala, Sweden.
    Karlsson, F Anders
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Fanni, Giovanni
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Sundbom, Magnus
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Haller, Sven
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Faculty of Medicine, University of Geneva, Geneva, Switzerland.
    Lubberink, Mark
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Wikström, Johan
    Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
    Eriksson, Jan W.
    Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden.
    Effects of Gastric Bypass Surgery on the Brain: Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia2021In: Diabetes, ISSN 0012-1797, E-ISSN 1939-327X, Vol. 70, no 6, p. 1265-1277Article in journal (Refereed)
    Abstract [en]

    While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by 18F-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.

  • 14.
    Andersen, Leon
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Appelblad, Micael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Svenmarker, Staffan
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Our initial experience of monitoring the autoregulation of cerebral blood flow during cardiopulmonary bypass2023In: The journal of extra-corporeal technology, ISSN 0022-1058, Vol. 55, no 4, p. 209-217Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Cerebral blood flow (CBF) is believed to be relatively constant within an upper and lower blood pressure limit. Different methods are available to monitor CBF autoregulation during surgery. This study aims to critically analyze the application of the cerebral oxygenation index (COx), one of the commonly used techniques, using a reference to data from a series of clinical registrations.

    METHOD: CBF was monitored using near-infrared spectroscopy, while cerebral blood pressure was estimated by recordings obtained from either the radial or femoral artery in 10 patients undergoing cardiopulmonary bypass. The association between CBF and blood pressure was calculated as a moving continuous correlation coefficient. A COx index > 0.4 was regarded as a sign of abnormal cerebral autoregulation (CA). Recordings were examined to discuss reliability measures and clinical feasibility of the measurements, followed by interpretation of individual results, identification of possible pitfalls, and suggestions of alternative methods.

    RESULTS AND CONCLUSION: Monitoring of CA during cardiopulmonary bypass is intriguing and complex. A series of challenges and limitations should be considered before introducing this method into clinical practice.

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  • 15.
    Andersson, Jonas
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ryberg, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sjöström, Lars-Göran
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Karpe, Fredrik
    NIHR Oxford Biomedical Research Centre, Churchill Hospital, Oxford, UK..
    Lindahl, Bernt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Long term effects of a diet intervention on adipose tissue blood flow, heart rate variability and endothelial function: a randomized controlled trialManuscript (preprint) (Other academic)
  • 16.
    Andersson, Jonas
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Sjöström, Lars-Göran
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hultin, Magnus
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Karpe, Fredrik
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Dysregulation of subcutaneous adipose tissue blood flow in overweight postmenopausal women2010In: Menopause: The Journal of the North American Menopause, ISSN 1072-3714, E-ISSN 1530-0374, Vol. 17, no 2, p. 365-371Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: A putative link between abdominal obesity and metabolic-vascular complications after menopause may be due to a decreased adipose tissue blood flow (ATBF). The present work aimed to analyze possible changes in ATBF with being overweight and menopausal and its putative link to endothelial dysfunction and autonomic nervous system balance.

    METHODS: Forty-three healthy women were classified into four groups according to weight and menopause status. The ATBF was measured by xenon washout while fasting and after oral glucose intake. The nitric oxide synthase inhibitor asymmetric dimethylarginine was used as a marker of endothelial function and heart rate variability-estimated autonomic nervous system activity.

    RESULTS: Fasting ATBF was decreased in both overweight groups (P = 0.044 and P = 0.048) versus normal-weight premenopausal women. Normal-weight and overweight postmenopausal women exhibited lower maximum ATBF compared with normal-weight premenopausal women (P = 0.015 and P = 0.001, respectively), and overweight postmenopausal women exhibited lower maximum ATBF compared with normal-weight postmenopausal women (P = 0.003). A negative correlation was found between fasting ATBF and asymmetric dimethylarginine (P = 0.015), whereas maximum ATBF was negatively associated with sympathetic-parasympathetic nervous system balance (ratio of the power of the low frequency to the power of the high frequency; P = 0.002).

    CONCLUSIONS: Loss of ATBF flexibility in overweight postmenopausal women may contribute to the metabolic dysfunction seen in this group of women.

  • 17.
    Andersson, Kennet
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Suhr, Ole B.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Faes, Luca
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Directed coherence analysis in patients with severe autonomic dysfunction2014In: 2014 8th conference of the European Study Group on Cardiovascular Oscillations (ESGCO), IEEE conference proceedings, 2014, p. 167-168Conference paper (Refereed)
    Abstract [en]

    Many different approaches have been applied to analyse the coupling between cardiovascular signals. This study evaluated the use of directed coherence, based on multivariate autoregressive modelling, for analysis of cardiovascular signals in patients with transthyretin amyloidosis, a rare disease where severe autonomic dysfunction is common.

  • 18.
    Andersson, Nina
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Adaptive method for assessment of cerebrospinal fluid outflow conductance.2007In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 45, no 4, p. 337-343Article in journal (Refereed)
    Abstract [en]

    Outflow conductance (C out) is important for predicting shunt responsiveness in patients with suspected idiopathic adult hydrocephalus syndrome (IAHS). C out is determined by performing an infusion test into the cerebrospinal fluid system, and the reliability of the test is dependent on the measurement time. The objective of this study was to develop an adaptive signal analysis method to reduce the investigation time, by taking the individual intracranial pressure variations of the patient into consideration. The method was evaluated on 28 patients with suspected IAHS. The results from full time investigations (60 min) were compared to the results of the new algorithm. Applying the new adaptive method resulted in a reduction of mean investigation time by 14.3 ± 5.9 min (mean ± SD), p < 0.01. The reduction of reliability in the C out estimation was found clinically negligible. We thus recommend this adaptive method to be used when performing constant pressure infusion tests.

  • 19. Bandaragoda, Tharindu
    et al.
    De Silva, Daswin
    Kleyko, Denis
    Osipov, Evgeny
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Alahakoon, Damminda
    Trajectory clustering of road traffic in urban environments using incremental machine learning in combination with hyperdimensional computing2019In: 2019 IEEE Intelligent Transportation Systems Conference (ITSC), IEEE, 2019, p. 1664-1670Conference paper (Refereed)
    Abstract [en]

    Road traffic congestion in urban environments poses an increasingly complex challenge of detection, profiling and prediction. Although public policy promotes transport alternatives and new infrastructure, traffic congestion is highly prevalent and continues to be the lead cause for numerous social, economic and environmental issues. Although a significant volume of research has been reported on road traffic prediction, profiling of traffic has received much less attention. In this paper we address two key problems in traffic profiling by proposing a novel unsupervised incremental learning approach for road traffic congestion detection and profiling, dynamically over time. This approach uses (a) hyperdimensional computing to enable capture variable-length trajectories of commuter trips represented as vehicular movement across intersections, and (b) transforms these into feature vectors that can be incrementally learned over time by the Incremental Knowledge Acquiring Self-Learning (IKASL) algorithm. The proposed approach was tested and evaluated on a dataset consisting of approximately 190 million vehicular movement records obtained from 1,400 Bluetooth identifiers placed at the intersections of the arterial road network in the State of Victoria, Australia.

  • 20.
    Björ, Bodil
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Karlsson, Marcus
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Näslund, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Acute effects on heart rate variability when exposed to hand transmitted vibration and noise.2007In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 81, no 2, p. 193-199Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: This study investigates possible acute effects on heart rate variability (HRV) when people are exposed to hand transmitted vibration and noise individually and simultaneously. METHODS: Ten male and 10 female subjects were recruited by advertisement. Subjects completed a questionnaire concerning their work environment, general health, medication, hearing, and physical activity level. The test started with the subject resting for 15 min while sitting down. After resting, they were exposed to one of four exposure conditions: (1) only vibration; (2) only noise; (3) both noise and vibration; or (4) a control condition of exposure to the static load only. All four exposures lasted 15 min and the resting time between the exposures was 30 min. A continuous electrocardiogram (ECG) signal was recorded and the following HRV parameters were calculated: total spectral power (P(TOT)); the spectral power of the very low frequency component (P(VLF)); the low frequency component (P(LF)); the high frequency component (P(HF)); and the ratio LF/HF. RESULTS: Exposure to only vibration resulted in a lower P(TOT) compared to static load, whereas exposure to only noise resulted in a higher P(TOT). The mean values of P(TOT), P(VLF), P(LF), and P(HF) were lowest during exposure to vibration and simultaneous exposure to vibration and noise. CONCLUSIONS: Exposure to vibration and/or noise acutely affects HRV compared to standing without these exposures. Being exposed to vibration only and being exposed to noise only seem to generate opposite effects. Compared to no exposure, P(TOT) was reduced during vibration exposure and increased during noise exposure.

  • 21.
    Boles, Usama
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology. Cardiology Department, Letterkenny University Hospital, Letterkenny, Co. Donegal, Ireland.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sharif, Zain
    David, Santhosh
    McGrory, Siobhan
    Henein, Michael Y.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology. Molecular & Clinical Sciences Research Institute, St. George University, London, UK.
    Cytokine Disturbances in Coronary Artery Ectasia Do Not Support Atherosclerosis Pathogenesis2018In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 19, no 1, article id 260Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Coronary artery ectasia (CAE) is a rare disorder commonly associated with additional features of atherosclerosis. In the present study, we aimed to examine the systemic immune-inflammatory response that might associate CAE.

    METHODS: Plasma samples were obtained from 16 patients with coronary artery ectasia (mean age 64.9 ± 7.3 years, 6 female), 69 patients with coronary artery disease (CAD) and angiographic evidence for atherosclerosis (age 64.5 ± 8.7 years, 41 female), and 140 controls (mean age 58.6 ± 4.1 years, 40 female) with normal coronary arteries. Samples were analyzed at Umeå University Biochemistry Laboratory, Sweden, using the V-PLEX Pro-Inflammatory Panel 1 (human) Kit. Statistically significant differences (p < 0.05) between patient groups and controls were determined using Mann-Whitney U-tests.

    RESULTS: The CAE patients had significantly higher plasma levels of INF-γ, TNF-α, IL-1β, and IL-8 (p = 0.007, 0.01, 0.001, and 0.002, respectively), and lower levels of IL-2 and IL-4 (p < 0.001 for both) compared to CAD patients and controls. The plasma levels of IL-10, IL-12p, and IL-13 were not different between the three groups. None of these markers could differentiate between patients with pure (n = 6) and mixed with minimal atherosclerosis (n = 10) CAE.

    CONCLUSIONS: These results indicate an enhanced systemic pro-inflammatory response in CAE. The profile of this response indicates activation of macrophages through a pathway and trigger different from those of atherosclerosis immune inflammatory response.

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  • 22.
    Boles, Usama
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Cardiology Department, Letterkenny University Hospital, Co Donegal, Ireland; Heart and Vascular centre, Cardiology Department, Mater Private Hospital, Dublin, Ireland.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Cardiology Department, Heart and Vascular Centre, Mater Private Hospital, Dublin, Ireland.
    David, Santhosh
    Ahmed, Khalid
    Henein, Michael Y.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine. Molecular and Clinical Sciences Research Institute, St George University, London, United Kingdom; Brunel University London, London, United Kingdom.
    Coronary artery ectasia carries a worse prognosis: a long-term follow-up study2019In: Polish Archives of Internal Medicine, ISSN 0032-3772, E-ISSN 1897-9483, Vol. 129, no 11, p. 833-835Article in journal (Refereed)
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  • 23.
    Brändström, Helge
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Karlsson, Marcus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Ängquist, Karl-Axel
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Haney, Michael
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Autonomic nerve system responses for normal and slow rewarmers after hand cold provocation: effects of long-term cold climate training2013In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 86, no 3, p. 357-365Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Differences among individuals concerning susceptibility to local cold injury following acute cold exposure may be related to function of the autonomic nervous system. We hypothesized that there are differences in heart rate variability (HRV) between individuals with normal or more pronounced vasoconstriction following cold exposure and that there is an adaptation related to prolonged cold exposure in autonomic nervous system response to cold stimuli.

    METHODS: Seventy-seven young men performed a cold provocation test, where HRV was recorded during cold hand immersion and recovery. Forty-three subjects were re-examined 15 months later, with many months of cold weather training between the tests. Subjects were analyzed as 'slow' and 'normal' rewarmers according to their thermographic rewarming pattern.

    RESULTS: For the 'pre-training' test, before cold climate exposure, normal rewarmers had higher power for low-frequency (P(LF)) and high-frequency (P(HF)) HRV components during the cold provocation test (ANOVA for groups: p = 0.04 and p = 0.005, respectively). There was an approximately 25 % higher P(HF) at the start in normal rewarmers, in the logarithmic scale. Low frequency-to-high frequency ratio (P(LF)/P(HF)) showed lower levels for normal rewarmers (ANOVA for groups: p = 0.04). During the 'post-training' cold provocation test, both groups lacked the marked increase in heart rate that occurred during cold exposure at the 'pre-training' setting. After cold acclimatization (post-training), normal rewarmers showed lower resting power values for the low-frequency and high-frequency HRV components. After winter training, the slow rewarmers showed reduced low-frequency power for some of the cold provocation measurements but not all (average total P(LF), ANOVA p = 0.05), which was not present before winter training.

    CONCLUSIONS: These HRV results support the conclusion that cold adaptation occurred in both groups. We conclude that further prospective study is needed to determine whether cold adaptation provides protection to subjects at higher risk for cold injury, that is, slow rewarmers.

  • 24.
    Erelund, Sofia
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Karp, Kjell
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Arvidsson, Sandra
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Johansson, Bengt
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Pulmonary function in a cohort of heart-healthy individuals from Northern Sweden: a comparison with discordant reference values2023In: BMC Pulmonary Medicine, E-ISSN 1471-2466, Vol. 23, no 1, article id 110Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Dynamic spirometry is an important investigation to differentiate between impaired and normal lung function. This study aimed to evaluate the results of lung function testing in a cohort of subjects from Northern Sweden without any known heart or pulmonary disease. Our focus was to compare with two reference materials that have showed differences in the age-dependency of lung function in Swedish subjects.

    METHODS: The study population consisted of 285 healthy adults (148 males, 52%) between 20-90 years of age. The subjects had been randomly selected from the population register for inclusion in a study investigating cardiac function in heart-healthy subjects, but were also assessed with dynamic spirometry. At least seven percent reported smoking. Sixteen subjects presented with pulmonary functional impairments and were excluded from the current study. The sex-specific age-dependency in lung volumes was estimated using the LMS model, where non-linear equations were derived for the mean value (M), the location (L) or skewness, and the scatter (S) or coefficient of variation. This model of the observed lung function data was compared with reference values given by the original LMS model published by the Global Lung Initiative (GLI), and with the model from the recent Obstructive Lung Disease In Norrbotten (OLIN) study, where higher reference values were presented for Swedish subjects than those given by the GLI model.

    RESULTS: No differences were found in the age-dependency of pulmonary function between the LMS model developed in the study and the OLIN model. Although the study group included smokers, the original GLI reference values suggested significantly lower normal values of FEV1 (forced expiratory volume) and FVC (forced vital capacity), and consequently fewer subjects below the lower limit of normality, than both the rederived LMS and OLIN models.

    CONCLUSIONS: Our results are in line with previous reports and support that the original GLI reference values underestimate pulmonary function in the adult Swedish population. This underestimation could be reduced by updating the coefficients in the underlying LMS model based on a larger cohort of Swedish citizens than was available in this study.

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  • 25.
    Erelund, Sofia
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Karp, Kjell
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Hörnsten, Rolf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Arvidsson, Sandra
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Are ECG changes in heart-healthy individuals of various ages related to cardiac disease 20 years later?2021In: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 126, no 1, article id e6064Article in journal (Refereed)
    Abstract [en]

    Background: This research study aimed at assessing the electrocardiographic (ECG) changes caused by ageing in a cohort of healthy subjects with normal echocardiographic examinations.

    Methods: A total of 219 healthy individuals (119 males and 100 females) were evaluated for possible arrhythmias with a standard 12-lead resting ECG and 24-h Holter ECG. As the recordings were performed between 1998 and 2000, a 20-year follow-up study was carried out by assessing the local medical records to investigate whether the subjects had experienced any cardiovascular health complications or disease since the baseline assessment.

    Results: Eighty-three subjects (45 males and 38 females) presented with pathological ECG findings at baseline. The most common finding on analysis of Holter ECG recordings was premature atrial contractions, and the most severe pathological finding was episodes of ventricular tachycardia (eight subjects). Regarding the analysis of the standard 12-lead ECG, the most common finding was left ventricular hypertrophy, and the most severe pathological findings were ST-T changes and prolongation of the QT interval. Despite other cardiac examinations performed on these patients showing normal results, in combination with a strict inclusion criterion, this study showed that 28% of all subjects had pathological resting 12-lead ECGs at rest and 35% had pathological heart rhythms when assessed by 24-h Holter ECG. At follow-up, 21% of females and 43% of males had presented with ECG abnormalities, and 30% of females and 36% of males had cardiovascular disease. There was hypertension in 45% of females and in 58% of males. However, no association was found between the follow-up findings and ECG changes seen at baseline.

    Conclusion: Although most ECG changes found at baseline could be considered as a normal variation, they may progress to more severe heart complications as the subject ages. The results of this study also validate ECG findings of previous studies and underline that diagnostic criteria should be based on gender and age.

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  • 26.
    Erelund, Sofia
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Slunga-Järvholm, Lisbeth
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Nordendahl, Maria
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Johansson, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Heart rate variability and long-term survival in females with ischemic heart diseaseManuscript (preprint) (Other academic)
  • 27.
    Erelund, Sofia
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Södergren, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Sundström, Nina
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Heart rate variability and cardiovascular risk factors in patients with rheumatoid arthritis: a longitudinal study2023In: Autonomic Neuroscience: Basic & Clinical, ISSN 1566-0702, E-ISSN 1872-7484, Vol. 249, article id 103119Article in journal (Refereed)
    Abstract [en]

    Background: It is established that the risk of cardiovascular disease (CVD) is increased in patients with Rheumatoid Arthritis (RA). Heart rate variability (HRV) is a method for evaluating the activity in the cardiac autonomic nervous system. Our aim was to assess the longitudinal development of HRV in patients with RA and compare with healthy controls. Furthermore, we wanted to investigate associations between HRV, inflammatory disease activity and cardiovascular complications in patients with RA over time.

    Method: HRV was assessed with frequency-domain analysis at baseline and after five years in 50 patients with early RA, all being younger than 60 years. HRV indices were age-adjusted based on the estimated age-dependency in 100 age and sex matched healthy controls. Additionally, clinical data including serological markers, disease activity, and blood pressure were collected from the patients. Eleven years after inclusion CVD was assessed.

    Results: At baseline, patients with RA presented with lower HRV compared to controls during deep breathing (6 breaths/min), paced normal breathing (12 breaths/min) and after passive tilt to the upright position. No significant change in HRV was observed at the five-year follow-up. A significant negative correlation was found between HRV parameters and systolic blood pressure (SBP) at baseline. A significant positive correlation was found between heart rate and inflammatory markers at baseline but not after five years. Nine patients had developed CVD after 11 years, but no significant association was found with baseline HRV data.

    Conclusion: This study showed that patients with RA have autonomic imbalance both at an early stage of the disease and after five years, despite anti-rheumatic medication, but no correlation between HRV and inflammation markers were observed. Reduced HRV was also significantly negatively correlated with increased SBP. Hypertension is a common finding in patients with RA. Thus, significant decline of HRV could be a useful early marker for development of hypertension in patients with RA.

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  • 28.
    Granåsen, Gabriel
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Karlsson, Markus
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. marcus.karlsson@regionvasterbotten.se.
    Westermark, Per
    Institutionen för immunologi, genetik och patologi, Uppsala universitet.
    Grönlund, Christer
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Suhr, Ole B.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Multimodal analysis of the pattern of disturbances in heart rate variability and echocardiographic features in patients with hereditary transthyretin amyloidosis and hypertrophic cardiomyopathyManuscript (preprint) (Other academic)
  • 29.
    Granåsen, Gabriel
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Multivariate Classification of Cardiac Autonomic Function and Echocardiographic Abnormalities2013In: 2013 COMPUTING IN CARDIOLOGY CONFERENCE (CINC), 2013, p. 1151-1154Conference paper (Refereed)
    Abstract [en]

    Abnormalities in the function, physiology and the regulation of the heart can be diagnosed using echocardiography (ECHO) and analysis of heart rate variability (HRV). Patients with transthyretin amyloidosis often present increased wall thickness in the myocardium and/ or autonomic dysfunction. We used a novel approach to analyse the relationship between these findings, using a combination of dimension reduction techniques and model based clustering.

  • 30.
    Grip, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Sterner, Ylva
    Karlsson, J Stefan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Gerdle, Björn
    Classification of neck movement patterns related to whiplash-associated disorders using neural networks2003In: IEEE transactions on information technology in biomedicine, ISSN 1089-7771, Vol. 7, no 4, p. 412-418Article in journal (Refereed)
    Abstract [en]

    This paper presents a new method for classification of neck movement patterns related to Whiplash-associated disorders (WAD) using a resilient backpropagation neural network (BPNN). WAD are a common diagnosis after neck trauma, typically caused by rear-end car accidents. Since physical injuries seldom are found with present imaging techniques, the diagnosis can be difficult to make. The active range of the neck is often visually inspected in patients with neck pain, but this is a subjective measure, and a more objective decision support system, that gives a reliable and more detailed analysis of neck movement pattern, is needed. The objective of this study was to evaluate the predictive ability of a BPNN, using neck movement variables as input. Three-dimensional (3-D) neck movement data from 59 subjects with WAD and 56 control subjects were collected with a ProReflex system. Rotation angle and angle velocity were calculated using the instantaneous helical axis method and motion variables were extracted. A principal component analysis was performed in order to reduce data and improve the BPNN performance. BPNNs with six hidden nodes had a predictivity of 0.89, a sensitivity of 0.90 and a specificity of 0.88, which are very promising results. This shows that neck movement analysis combined with a neural network could build the basis of a decision support system for classifying suspected WAD, even though further evaluation of the method is needed.

  • 31. Guo, Li
    et al.
    Berglin, Lena
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Mattila, Heikki
    Design of a garment-based sensing system for breathing monitoring2013In: Textile research journal, ISSN 0040-5175, E-ISSN 1746-7748, Vol. 83, no 5, p. 499-509Article in journal (Refereed)
    Abstract [en]

    The long-term monitoring of biophysiological signals requires new types of sensor systems that are wearable and at the same time convenient for the users. This paper describes the design of a novel garment-based sensing system for the long-term monitoring of breathing rhythm. The system concept was realized in a prototype garment, integrated with coated piezoresistive sensors. The prototype garment was tested by five subjects, and compared with a standard piezoelectric respiratory belt. Each signal was quantitatively and qualitatively evaluated in the time and frequency domain to make sure that no medical and diagnostic information was lost. The results showed a good agreement between the garment-based sensors and the standard reference, where errors occurred only when the breathing rate was extremely high. The garment-based sensor system could also distinguish the predominance breathing compartment (chest versus abdominal breathing). The system could detect a 10 s pause in breathing, which could be of importance in studies of sleep apnea. A garment-based sensing system maintains the accuracy of the signal quality without reducing the comfort for the user. It makes possible long-term ambulatory monitoring and has home-based healthcare applications.

  • 32.
    Gustafsson, Sandra
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Granåsen, Gabriel
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Grönlund, Christer
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Suhr, Ole B.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindqvist, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Discriminating hereditary transthyretin cardiomyopathy from hypertrophic cardiomyopathy using an echocardiographic and ECG based classification tree2014In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 35, no Supplement 1, Meeting abstract P5254, p. 929-929Article in journal (Other academic)
  • 33.
    Gustavsson, Sandra
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Granåsen, Gabriel
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Grönlund, Christer
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Mörner, Stellan
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Henein, Michael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Suhr, Ole B
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindqvist, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Can echocardiography and ECG discriminate hereditary transthyretin V30M amyloidosis from hypertrophic cardiomyopathy?2015In: Amyloid: Journal of Protein Folding Disorders, ISSN 1350-6129, E-ISSN 1744-2818, Vol. 22, no 3, p. 163-170Article in journal (Refereed)
    Abstract [en]

    Objective: Hereditary transthyretin (ATTR) amyloidosis with increased left ventricular wall thickness could easily be misdiagnosed by echocardiography as hypertrophic cardiomyopathy (HCM). Our aim was to create a diagnostic tool based on echocardiography and ECG that could optimise identification of ATTR amyloidosis. Methods: Data were analysed from 33 patients with biopsy proven ATTR amyloidosis and 30 patients with diagnosed HCM. Conventional features from ECG were acquired as well as two dimensional and Doppler echocardiography, speckle tracking derived strain and tissue characterisation analysis. Classification trees were used to select the most important variables for differentiation between ATTR amyloidosis and HCM. Results: The best classification was obtained using both ECG and echocardiographic features, where a QRS voltage >30 mm was diagnostic for HCM, whereas in patients with QRS voltage <30 mm, an interventricular septal/posterior wall thickness ratio (IVSt/PWt) >1.6 was consistent with HCM and a ratio <1.6 supported the diagnosis of ATTR amyloidosis. This classification presented both high sensitivity (0.939) and specificity (0.833). Conclusion: Our study proposes an easily interpretable classification method for the differentiation between HCM and increased left ventricular myocardial thickness due to ATTR amyloidosis. Our combined echocardiographic and ECG model could increase the ability to identify ATTR cardiac amyloidosis in clinical practice.

  • 34.
    Haney, Michael F.
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Can heart rate variability become a screening tool for anesthesia-related hypotension?2007In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 51, no 10, p. 1289-1291Article in journal (Refereed)
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  • 35.
    Hansson, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lind, T.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Öhlund, Inger
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Increased abdominal fat mass and high fat consumption in young school children with congenital heart disease: results from a case-control study2020In: Journal of human nutrition and dietetics, ISSN 0952-3871, E-ISSN 1365-277X, Vol. 33, no 4, p. 566-573Article in journal (Refereed)
    Abstract [en]

    Background We have previously found that infants with complex congenital heart disease (CHD) experience growth failure despite high-energy dietary supplementation. This is a follow-up and comparison with healthy controls at 9 years of age regarding body composition and macronutrient intake, especially in relationship to the diet provided during infancy. Methods Anthropometric changes in 10 children with CHD at 12 months and at 4 and 9 years of age were analysed as Z-scores. To assess body composition and food intake at 9 years of age, a dual-energy X-ray absorptiometry scan and a 3-day food diary were completed and compared with age- and gender-matched controls using Wilcoxon's signed-rank test for matched pairs. Results Growth changes from 12 months to 9 years, converted to Z-scores for weight for height and height for age, were significantly different within the group of children with complex CHD, although no growth differences were seen in comparison with healthy controls at 9 years of age. However, the children with CHD had statistically higher abdominal fat mass index and higher daily intake of fat, particularly from saturated fatty acid in g kg-1 compared to controls. Conclusions At 9 years of age, children with complex CHD with growth failure and high fat intake in infancy have normalised growth but increased abdominal fat mass and higher intake of saturated fatty acid compared to their peers. Nutritional monitoring in early childhood may detect unhealthy diet quality and prevent later health risks in this group.

  • 36.
    Hansson, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lind, Torbjörn
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhlund, Inger
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Fluid restriction negatively affects energy intake and growth in very low birthweight infants with haemodynamically significant patent ductus arteriosus2019In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 108, no 11, p. 1985-1992Article in journal (Refereed)
    Abstract [en]

    Aim: We explored if fluid restriction in very low birthweight (VLBW) infants with a haemodynamically significant patent ductus arteriosus (PDA) affected energy and protein intakes and growth.

    Methods: Retrospectively, we identified 90 VLBW infants that were admitted to Umea University Hospital, Sweden, between 2009 and 2012: 42 with and 48 without haemodynamically significant PDA (hsPDA). Anthropometric, fluid, energy and protein intake data during the first 28 days of life were expressed as z‐scores.

    Results: In the 42 infants diagnosed with hsPDA, fluid intake was restricted after diagnosis, resulting in a decrease in energy and protein intake. No decrease was observed in the other 48 infants in the cohort. Multivariate analysis showed that the z‐score of weight change depended on both ductus arteriosus status and energy intake; thus, infants with hsPDA did not grow as expected with the energy provided to them.

    Conclusion: Energy and protein intake was diminished in prematurely born infants with hsPDA when fluid was restricted after diagnosis. The initial reduction in intakes may have contributed to the lower postnatal growth observed in these infants.

  • 37.
    Hansson, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Sandberg, Camilla
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Öhlund, Inger
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lind, Torbjörn
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Sthen Bergdahl, Magne
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Rylander Hedlund, Eva
    Department of Women’s and Children’s Health, Division of Pediatric Cardiology, Karolinska Institutet, Stockholm, Sweden.
    Sjöberg, Gunnar
    Department of Women’s and Children’s Health, Division of Pediatric Cardiology, Karolinska Institutet, Stockholm, Sweden.
    Rydberg, Annika
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Vitamin D, liver-related biomarkers, and distribution of fat and lean mass in young patients with Fontan circulation2022In: Cardiology in the Young, ISSN 1047-9511, E-ISSN 1467-1107, Vol. 32, no 6, p. 861-868Article in journal (Refereed)
    Abstract [en]

    Introduction/aim: Young patients with Fontan circulation may have low serum 25-hydroxyvitamin D levels, an affected liver, and unhealthy body compositions. This study aimed to explore the association between vitamin D intake/levels, liver biomarkers, and body composition in young Fontan patients.

    Method: We collected prospective data in 2017 to 2018, obtained with food-frequency questionnaires, biochemical analyses of liver biomarkers, and dual-energy X-ray absorptiometry scans in 44 children with Fontan circulation. Body compositions were compared to matched controls (n = 38). Linear regression analyses were used to investigate associations of biomarkers, leg pain, and lean mass on serum levels of 25-hydroxyvitamin D. Biomarkers were converted to z scores and differences were evaluated within the Fontan patients.

    Results: Our Fontan patients had a daily mean vitamin D intake of 9.9 µg and a mean serum 25-hydroxyvitamin D of 56 nmol/L. These factors were not associated with fat or lean mass, leg pain, or biomarkers of liver status. The Fontan patients had significantly less lean mass, but higher fat mass than controls. Male adolescents with Fontan circulation had a greater mean abdominal fat mass than male controls and higher cholesterol levels than females with Fontan circulation.

    Conclusion: Vitamin D intake and serum levels were not associated with body composition or liver biomarkers in the Fontan group, but the Fontan group had lower lean mass and higher fat mass than controls. The more pronounced abdominal fat mass in male adolescents with Fontan circulation might increase metabolic risks later in life.

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  • 38.
    Hedelin, Rikard
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Bjerle, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Henriksson-Larsén, K
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Cardiac autonomic imbalance in an overtrained athlete.2000In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 32, no 9, p. 1531-1533Article in journal (Refereed)
    Abstract [en]

    PURPOSE: In order to investigate overtraining-related adaptations in the autonomic nervous system, cardiac autonomic activity was examined in a junior cross-country skier who presented with reduced performance in competitions, early breathlessness during training sessions, and accumulated central fatigue. METHODS: Power spectral analysis of heart rate variability (HRV) was performed before, when overtrained (OT), and after recovery (Rec). RESULTS: In the overtrained state, high frequency (HF) and total powers in the lying position were higher compared with before and after. In normalized units, the increased HF in OT was even more prominent and clearly higher than in any control subject, and it was reversed in Rec. Resting heart rate was slightly reduced in OT and returned to baseline in Rec. CONCLUSIONS: The shift toward increased heart rate variability, particularly in the HF range, together with a reduced resting heart rate suggest a cardiac autonomic imbalance with extensive parasympathetic modulation in this athlete when overtrained.

  • 39.
    Heldestad, Victoria