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- Höijer, Carl Johan, et al.
(författare)
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Single chamber atrial pacing: A realistic option in sinus node disease: A long-term follow-up study of 213 patients
- 2007
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 30:6, s. 740-747
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Tidskriftsartikel (refereegranskat)abstract
- Background: Despite several decades of experience with atrial pacing, many centers do not apply this mode to any greater extent, mainly because of concerns for the development of future atrioventricular (AV) block or atrial fibrillation. Recent studies have emphasized possible negative effects of right ventricular stimulation, even when AV-synchrony is preserved, and have thus given rise to renewed interest in single chamber atrial pacing for sinus node disease. Methods: This study presents the results of up to 19 years' follow-up of 213 patients with sinus node disease treated with atrial pacing with respect to survival and causes of death, development of atrial fibrillation and AV block, and total mode survival. Patients were divided into two groups: with or without associated atrial tachyarrhythmias at the time of implant. Results are given for all patients and for the two groups separately. Results: The mean follow-up time was 10.1 years. The survival of the entire group was lower after 10 years than that of an age and gender-matched general Swedish population. This was caused by patients with the brady-tachy syndrome (BT) having a significantly higher mortality rate than controls, whereas those with bradycardia only (B) had survival comparable to the general population. Permanent atrial fibrillation (AF) developed in 20% of patients and was significantly more common in patients with BT. The majority of patients with AF (78%) no longer needed any pacing, i.e., did not require ventricular stimulation due to slow ventricular rate. The annual incidence of high grade AV block was 1.8%. If patients with preexisting bundle branch block were excluded, the incidence was 1.6%. No fatal episode of AV block was seen. The overall mode survival at the end of follow-up was 75%, with 155 patients still with atrial pacemakers. Conclusion: Atrial pacing is a safe and reliable mode of pacing in patients with sinus node disease, even in the very long-term.
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| 2. |
- Lundstedt-Enkel, Katrin, et al.
(författare)
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A Statistical Resampling Method To Calculate Biomagnification Factors Exemplified with Organochlorine Data from Herring (Clupea harengus) Muscle and Guillemot (Uria aalge) Egg from the Baltic Sea
- 2005
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Ingår i: ENVIRONMENTAL SCIENCE & TECHNOLOGY. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 39:21, s. 8395-8402
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Tidskriftsartikel (refereegranskat)abstract
- A novel method for calculating biomagnification factors is presented and demonstrated using contaminant concentration data from the Swedish national monitoring program regarding organochlorine contaminants (OCs) in herring (Clupea harengus) muscle and guillemot (Uria aalge) egg, sampled from 1996 to 1999 from the Baltic Sea. With this randomly sampled ratios (RSR) method, biomagnification factors (BMFRSR) were generated and denoted with standard deviation (0) as a measure of the variation. The BMFRSR were calculated by randomly selecting one guillemot egg out of a total of 29 and one herring out of a total of 74, and the ratio was determined between the concentration of a given OC in that egg and the concentration of the same OC in that herring. With the resampling technique, this was performed 50 000 times for any given OC, and from this new distribution of ratios, BMFRSR for each OC were calculated and given as geometric mean (GM) with GM standard deviation (GMSD) range, arithmetic mean (AM) with AMSD range, and minimum (BMFMIN) as well as maximum (BMFMAX) biomagnification factors. The 14 analyzed OCs were p,p'DDT and its metabolites p,p'DDE and p,p'DDD, polychlorinated biphenyls (PCB congeners: CB28, CB52, CB101, CB118, CB138, CB153, and CB180), hexachlorocyclohexane isomers (alpha-, beta-, and gamma HCH), and hexachlorobenzene (HCB). Multivariate data analysis (MVDA) methods, including principal components analysis (PCA), partial least squares regression (PLS), and PLS discriminant analyses (PLS-DA), were first used to extract information from the complex biological and chemical data generated from each individual animal. MVDA were used to model similarities/dissimilarities regarding species (PCA, PLS-DA), sample years (PLS), and sample location (PLS-DA) to give a deeper understanding of the data that the BMF modeling was based upon. Contaminants that biomagnify, that had BMFRSR significantly higher than one, were p,p'DDE, CB118, HCB, CB138, CB180, CB153, beta HCH, and CB28. The contaminants that did not biomagnify were p,p'DDT, p,p'DDD, alpha HCH, CB101, and CB52. Eventual biomagnification for gamma HCH could not be determined. The BMFRSR for OCs present in herring muscle and guillemot egg showed a broad span with large variations for each contaminant. To be able to make reliable calculations of BMFs for different contaminants, we emphasize the importance of using data based upon large numbers of, as well as well-defined, individuals.
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