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Background Timely detection and treatment of hypertension prevents cardiovascular diseases. Formerly preeclamptic women are at increased risk for hypertension, but targeted and structural follow-up of these women is lacking. Purpose To develop a prediction model for the development of hypertension in the decade following preeclampsia in women who were initially normotensive shortly after pregnancy. Methods In this longitudinal cohort study, formerly preeclamptic women were invited twice for a cardiovascular assessment. The first visit took place at a median interval of 10 months after delivery and a second visit 10 years later as part of the Queen of Hearts cohort study on early detection of heart failure among young women with a history of preeclampsia (ClinicalTrials.gov Identifier NCT02347540). Normotensive women at the first visit were divided in two groups whether or not they had developed hypertension during visit 2. Hypertension was defined as SBP ≥130 mmHg and/or DBP ≥80 mmhg and/or use of antihypertensive medication. We developed a prediction model using multivariable logistic regression analysis. The model was internally validated with bootstrapping techniques. Results Of the 259 women, 185 (71%) were normotensive at first visit of which 49 (26%) had developed hypertension at the second visit. The prediction model, based on birth weight centile, mean arterial pressure, total cholesterol, left ventricular mass index and left ventricular ejection fraction, had a good to excellent discriminative ability of AUC-ROC-curve 0.82 (95% CI 0.75–0.89) with an optimism corrected AUC of 0.80. Sensitivity and specificity of our model to predict yearly 10% risk to develop hypertension was 98% and 65% respectively and positive- and negative-predictive values were 50% and 99% respectively. Conclusions Based on five easily available variables, we developed a good-to-excellent performing predictive tool to identify incident hypertension following preeclampsia in women that were normotensive shortly after pregnancy. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): This work was partially supported by funding of de Nederlandse Hartstichting (Dutch Heart Foundation, grant number: 2013T084, Queen of Hearts study)

BackgroundOur objective was to investigate trends over time in longevity and reasons for replacement with or without extraction of pacemaker leads after first implantation.MethodsData collected between 1984 and 2006 in the national Dutch pacemaker registry were used. This registry covered 84% of sold leads. First lead replacement with or without extraction of one or more leads implanted with a first pacemaker generator was the endpoint of interest. The time interval of and reason for first replacement were analyzed. A 7-year follow-up interval after first implantation was used to analyze changes over time.ResultsDuring 22 years of data collection, 138,225 leads were implanted with a first pacemaker generator. Within a mean 5.5 (SD 4.4) years for 7,377 patients one or more leads were extracted for the first time. In total, 8,849 leads (6.4%) were replaced or extracted. The main reasons for first replacement of leads with or without extraction were insulation failures (14.6%), infection (8.8%), displacement (7.6%), or for elective reasons (10.0%). The number of insulation failures peaked during 1991-1995.ConclusionsDespite improvements in pacing techniques and experience with cardiac devices, we found that insulation and conductor failures, and complications such as infections, did not diminish over the 20 years of the registry. Continuing attention in clinical practice for the evaluation of these adverse outcomes and maintaining quality registries is warranted, whereas manufacturers should use this information to further improve their devices.

Aims: After decades of experience and strongly improved technology, service time of pacemaker generators is expected to increase. To test this hypothesis, we conducted a retrospective review of a large cohort of patients with a pacemaker.Methods: We reviewed data collected between 1984 and 2006 in the first national Dutch pacemaker registry. This registry covered 96% of all generators implanted. We analysed the time of and reason for explantation of pacemaker generators. A 7-year follow-up interval after first implantation and following replacements was used to analyse changes over time.Results: During 22 years of data collection, nearly 97,000 first pacemaker generators were implanted. A total of 27,937 (22.4%) generators were explanted within a mean of 6.3 (standard deviation 3.3) years. Reasons for approximately 60% of these explantations were ` end of life' of the pacemaker generator or elective system change. Complications or failures such as infections and recalls accounted for approximately 20% of the explantations. For the remaining 20%, the reasons for explantation had not been registered.Conclusion: Despite progress in technology, a substantial proportion of pacemaker generators is explanted before its expected service time, with one in five generators being replaced due to technical failures, infections or other complications. Furthermore, the time interval between pacemaker implantation and explantation due to normal 'end of life' (battery EOL) decreased. Infections continue to rank highly as a cause for pacing system replacement, despite all current preventive measures.

The implantation of cardiac pacemakers has become a well-established therapy for conduction disorders and sinus node dysfunction. In many countries pacemaker registries have been initiated in order to collect information on patient characteristics, trends in numbers and the types of pacemakers used, to identify problematic devices, and for safety monitoring. For this utilisation study the Central Pacemaker Patients Registration (CPPR) from the Netherlands Pacemaker Registry Foundation (CPPR-SPRN) containing data collected for more than 20 years was used. During this period nearly 97,000 first pacemakers were implanted. Analyses show an increase in the rate of implanted devices. The change in pacemaker type from VVI to DDD, followed by biventricular stimulation, is reflected by the number of simultaneously implanted leads, which is partly a consequence of cardiac resynchronisation therapy. Our data demonstrate that indications for implantation and type of pacemaker are comparable with other European countries.

Measuring distance in short-range radio devices greatly enhances the user experience. The distance information gives the user the opportunity to make intelligent decisions to which device in range he may want to connect. Previous efforts using radio signal strength or ultra-wideband technologies have not shown to be successful. In this paper, a narrowband RF technique is presented that is based on phase locking in phase modulated RF signals. The technique is compatible with existing technologies like Bluetooth and IEEE 802.15.4 systems. Simulations match well with theory. Experimental results with a prototype operating at 2.4 GHz show that accuracies below 0.5 m are well within reach.

Partial Least Squares (PLS) was used to develop Quantitative Structure-Property Relationships (QSPRs) to analyze substrate structures in asymmetric ketone hydrogenation reactions with Noyori's catalyst. For a set of benzophenone substrates, PLS models were obtained which could correlate the substrate structure to the product enantiomeric excess (e.e.). The structural conformation used for calculating some of the descriptors was found to be important for obtaining satisfying model properties. Acceptable R 2 and Q 2 values could be obtained despite the small training data set of only 13 benzophenones. The model was subsequently used for the systematic estimation of product e.e. values for a series of other benzophenone substrates. Reaction results for two benzophenones show that the model can correctly indicate a low, medium or high expected e.e. value.

The feasibility of enantiomeric excess (ee) prediction is demonstrated for asymmetric oxazaborolidine mediated ketone reduction. A quantitative structure-selectivity (QSSR) model of chiral oxazaborolidines was created by using multivariate data analysis. High-throughput methods and regression techniques were used to correlate the model with the ee’s of reactions with a training set and to predict the ee’s for an additional set of oxazaborolidines. The predicted ee’s corresponded well with the actual values, indicating that the model is very useful for the initial selection of catalysts for screening experiments.

Aims Guidelines regarding pacemaker (PM) follow-up (FU) are not precisely defined. The study aim is to describe long-term routine in-hospital FU, evaluate compliance to guidelines, and assess the portion of visits-with-an-action (VWA). Methods and results The multicentre prospective FOLLOWPACE study collected data in the period 2003–2010, regarding FU of 1517 patients with a first PM for bradycardia indications in 23 Dutch hospitals. A total of 15 472 visits were analysed with a median FU of 4.9 years, adding up to 6750 patient years. The median time to the first three visits was 35, 127, and 303 days, respectively. Thereafter the median interval between visits was 180 days. Most patients had 2 FU/year, 22% had 1 FU/year, and 18% had >3 FU/year. Seventy-three percent of patients with single-chamber PMs had at least 1 FU/year, whereas 36% of patients with dual-chamber PMs received at least 2 FU/year. During the first year, 52% of visits were VWA, as opposed to 17% after 6 years. Battery status was assessed in 98%, and stimulation and sensing thresholds in 90% and 77% of visits, respectively. Reprogramming markedly declined from ∼60% in the first FU visit to 10–20% after the fifth visit. Conclusion Although the measurements during PM FU are according to guidelines, the frequency of FU is not. Moreover, in the vast majority of performed FU, PM programming is left unchanged. This suggests that a large portion of FU visits is redundant, such that their frequency after the first year can be diminished, or replaced by remote FU.

After the implantation of the first pacemakers in the Netherlands, controlling the quality of the implantation procedure and the device became an important issue for cardiologists, technicians and manufacturers. Over the years, the cooperation between the different workers in this field led to the development of new devices and novel features in the pacemakers, ensuring improvement in the quality of life of the pacemaker patient. This article gives an impression of how registration in national and local novel systems contributed to this development. (Neth Heart J 2008;16(Suppl1):S9-S11.).

After the implantation of the first pacemakers in the Netherlands, controlling the quality of the implantation procedure and the device became an important issue for cardiologists, technicians and manufacturers. Over the years, the cooperation between the different workers in this field led to the development of new devices and novel features in the pacemakers, ensuring improvement in the quality of life of the pacemaker patient. This article gives an impression of how registration in national and local novel systems contributed to this development. (Neth Heart J 2008;16 (Suppl 1):S9-S11.)