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Sökning: WFRF:(Sandstedt Bengt 1951)

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1.
  • Gottfridsson, Christer, 1958, et al. (författare)
  • Spectral turbulence and late potentials in the signal-averaged electrocardiograms of patients with monomorphic ventricular tachycardia versus resuscitated ventricular fibrillation.
  • 2000
  • Ingår i: Scandinavian cardiovascular journal : SCJ. - 1401-7431. ; 34:3, s. 261-71
  • Tidskriftsartikel (refereegranskat)abstract
    • Signal-averaged electrocardiograms (SAECG) were analyzed for late potentials and spectral turbulence in 208 patients with ischemic heart disease with a history of sustained monomorphic ventricular tachycardia (MVT) (n = 62), resuscitation from ventricular fibrillation (VF) (n = 64) or no ventricular tachyarrhythmia (n = 82). Receiver operating characteristic curves were utilized to optimize cut-off values for prediction of MVT and VF. Patients with MVT had a lower ejection fraction (mean = 0.37) than patients with VF (0.44; p = 0.01) and controls (0.48; p < 0.0001). The mean FQRSD in MVT patients (126 ms) was longer than in VF and controls (113 ms; p = 0.005 and 102 ms; p < 0.0001, respectively). The RMS40 was lower in MVT (19 microV) than in VF and controls (29 microV; p = 0.0003 and 28 microV; p < 0.0001, respectively); 81% of the MVT patients were spectral turbulence-positive vs 47% of VF patients and 31% of control patients (p < 0.0001 for both differences). With optimized reference values, FQRSD, TQRSD and ISCSD contributed significantly to the identification of MVT patients and FQRSD to VF patients. The sensitivity of combined time-domain and spectral turbulence analysis was 90% for MVT and 58% for VF, with 63% specificity. MVT patients had a lower ejection fraction and were more often late potential and spectral turbulence positive than VF and control patients. These findings indicate that a large electroanatomic substrate is required in MVT. A long FQRSD was a risk marker for both MVT and VF. Spectral turbulence analysis added independent information, and the combination of time-domain and spectral turbulence analysis was superior to either method alone in identifying the MVT patients. Neither method of analysis, singly nor in combination, performed satisfactorily in identification of VF risk.
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2.
  • Krona, Cecilia, 1976, et al. (författare)
  • Analysis of neuroblastoma tumour progression; loss of PHOX2B on 4p13 and 17q gain are early events in neuroblastoma tumorigenesis
  • 2008
  • Ingår i: International Journal of Oncology. - 1019-6439. ; 32:3, s. 575-583
  • Tidskriftsartikel (refereegranskat)abstract
    • Neuroblastomas are biologically and clinically heterogeneous tumours that most often occur sporadically in children at median age 2. The PHOX2B gene is implicated in the development of the autonomic nervous system and has been found to be infrequently mutated in sporadic neuroblastoma tumours and in some patients with hereditary neuroblastoma. We have screened a selected series of 36 paediatric tumours with presumed genetic predisposition, 34 of them neuroblastomas, for mutations in PHOX2B. A constitutional heterozygous missense mutation was found in a boy who developed bilateral adrenal tumours and stage 4 disease during infancy. The second allele of the PHOX2B locus was lost in the tumour DNA. Histopathological evaluation of the tumours suggested growth of two primary tumours, one with diploid DNA content and the other with tetraploid DNA content, i.e. a case of neuroblastoma stage 4M (multifocal tumour). However, array CGH (comparative genomic hybridization) data performed on both tumour masses from the patient instead supported a model where a common malignant precursor gave rise to the diploid tumour and subsequently the tetraploid tumour have progressed from the common precursor or by metastasis from the diploid tumour with additional genetic changes. The whole genome dosage analysis showed that the remaining alleles of PHOX2B had been lost in both tumours together with a specific 17q gain pattern. The tetraploid tumour had these features together with additional whole chromosomal loss of chromosomes 3, 9, 14, and 15. Based on the data presented here we suggest that loss of PHOX2B and 17q gain are early events in neuroblastoma tumourigenesis. We also propose investigators to re-analyze the rare cases of multifocal neuroblastomas with the array CGH technique for better understanding of the origin of these tumours.
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3.
  • Sandstedt, Bengt, 1951, et al. (författare)
  • Genuine effects of ventricular fibrillation upon myocardial blood flow, metabolism and catecholamines in patients with aortic stenosis.
  • 2004
  • Ingår i: Scandinavian cardiovascular journal : SCJ. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 38:2, s. 113-20
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: Ventricular fibrillation (VF) is life-threatening because of its haemodynamic and metabolic effects. The purpose was to examine if VF also has primary effects per se. We therefore investigated the early effects of VF on myocardial blood flow, metabolic characteristics and catecholamine concentrations in patients undergoing surgery for aortic stenosis. DESIGN: The immediate effects of up to 5 min of VF were studied in 21 patients during cardiopulmonary bypass (CPB) before valve replacement. RESULTS: During VF the global myocardial oxygen consumption, coronary blood flow and vascular resistance were unchanged, and the mean arterial pressure (on CPB) decreased from 70 to 51 mmHg (p < 0.02). Fibrillation induced a high myocardial tone and a probable functional aortic insufficiency, which instantly equilibrated left ventricular and aortic pressures. Signs of myocardial ischaemia and acidosis developed after 4 min: a decrease in the pH of coronary sinus blood from 7.38 to 7.32 (p < 0.001), an increased release of lactate from 32 to 137 micromol/min (p < 0.001) and potassium from 29 to 73 micromol/min (p < 0.05). The noradrenaline net release increased from 0.021 to 0.58 nmol/min (p < 0.02) after 1.5 min of VF and then decreased. The adrenaline net uptake remained low and unchanged (17-28%). CONCLUSION: VF in patients with aortic stenosis was rapidly followed by myocardial ischaemia, acidosis and a transient increase in the myocardial noradrenaline net release despite sufficient coronary perfusion and unchanged global myocardial oxygen consumption. The VF instantly induced equilibration of left ventricular and aortic pressure and probably caused a relative underperfusion of the subendocardium. These factors all support persistence of VF.
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4.
  • Sandstedt, Bengt, 1951 (författare)
  • Studies on malignant ventricular tachyarrhythmias and their treatment with an implantable defibrillator
  • 2004
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Aims: To investigate the hemodynamic, metabolic and autonomic effects of ventricular fibrillation per se during maintained circulation. To study the defibrillation threshold (DFT) and efficacy of a new and thinner ICD lead (DSP) compared with the standard lead (C). To study the effects of pectoral or abdominal generator positioning on bidirectional and biphasic defibrillation. To study if the results of perioperative induction testing data would make postoperative ICD induction testing unnecessary. The evaluate the effects of time, exercise and amiodarone on an electrogram morphology discriminator. Methods: The coronary sinus flow (CSF), systemic and left ventricular pressure, myocardial oxygen consumption, metabolic products and catecholamine were analyzed in patients with aortic stenosis during induction of ventricular fibrillation (VF) with ongoing cardiopulmonary bypass. DSP and C leads DFT and pacing data from implantation and during follow-up were compared. The effect on DFT was studied by an alternating step-down protocol with an ICD in abdominal and a pectoral position in the same patient. Peroperative and postoperative ICD induction tests were performed and the relative and absolute defibrillation energy efficacy was analyzed. The effects of time, exercise and amiodarone therapy on the algorithm function were studied.Results: Myocardial ischemia, acidosis and a temporary noradrenalin net release developed during 4 min of VF despite an unchanged CSF and global myocardial oxygen consumption. The aortic and left ventricular pressure equilibrated rapidly after start of VF start. In the DSP both performed equally well. Abdominal or pectoral position did not affect the DFT. A relative energy of d 10J and an absolute defibrillation energy of T 20J at implantation could have made 89% of the predischarge tests unnecessary. The mean long-term MD function was not changed over time, at exercise or treatment of amiodarone. Transient miss-classification of electrograms occurred over time and during tachycardias.Conclusions: VF, per se, rapidly induced signs of myocardial ischemia, acidosis and a transient increase in noradrenaline release as well as an equilibration of the left ventricular and aortic pressures. Both the DSP and the C electrode were safe and effective in the treatment of ventricular tachyarrhythmias. No difference was found between the abdominal and pectoral positions in the same patient. The combined criteria of a relative defibrillation margin of 10 J and an absolute energy of 20 J at ICD implantation could be used without risk to reduce the need of postoperative induction testing to 11%. The morphological electrogram discrimination function showed stable mean values over time, during an exercise test and during amiodarone treatment. Single, transient, false low morphology discrimination scores were found during follow-up. The morphology discrimination must be frequently automatically updated and combined with other detection enhancements.
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5.
  • Sandstedt, Bengt, 1951, et al. (författare)
  • Testing the implantable cardioverter-defibrillator after implantation--is it necessary?
  • 2007
  • Ingår i: Pacing Clin Electrophysiol. - 0147-8389. ; 30:8, s. 985-91
  • Tidskriftsartikel (refereegranskat)abstract
    • The results of intraoperative and postoperative predischarge implantable cardioverter-defibrillator (ICD) testing of 211 consecutive patients, starting at 15 J and requiring two successful terminations of induced VT/VF with a relative defibrillation safety margin (DSM) of >10 J, were reviewed. The aim was to define the type of intraoperative response that would make postoperative predischarge testing unnecessary. The intraoperative responses were divided into three types: A, a DSM > or =10 J and an absolute energy level of < or =20 J; B, a DSM of > or =10 J and an absolute energy level of >20 J; and C, a DSM <10 J and an absolute energy level of >20 J. At operation, the responses to defibrillation were A, 88.6%; B, 7.1%; and C, 4.3%. Accepting an A response only would leave 11.4% of the patients for postoperative testing. The positive and negative predictive values for diagnosing a postoperative C response were 0.78 and 0.97, respectively. Similarly, the predictive values for diagnosing a postoperative B or C response were 0.71 and 0.97, respectively. The postoperative testing responses were A, 89.1%; B, 4.3%; and C, 6.6%. In summary, an intraoperative A response was sufficient to make a postoperative defibrillation testing unnecessary, while it was found that intraoperative B and C responders should undergo postoperative testing. Applying these criteria, approximately 90% of the patients could be discharged without any postoperative induction test.
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