Evidence to support magnetic resonance conditional labelling of all pacemaker and defibrillator leads in patients with cardiac implantable electronic devices

Aims: Many cardiac pacemakers and defibrillators are not approved by regulators for magnetic resonance imaging (MRI). Even following generator exchange to an approved magnetic resonance (MR)-conditional model, many systems remain classified ‘non-MR conditional’ due to the leads. This classification makes patient access to MRI challenging, but there is no evidence of increased clinical risk. We compared the effect of MRI on non-MR conditional and MR-conditional pacemaker and defibrillator leads. // Methods and results: Patients undergoing clinical 1.5T MRI with pacemakers and defibrillators in three centres over 5 years were included. Magnetic resonance imaging protocols were similar for MR-conditional and non-MR conditional systems. Devices were interrogated pre- and immediately post-scan, and at follow-up, and adverse clinical events recorded. Lead parameter changes peri-scan were stratified by MR-conditional labelling. A total of 1148 MRI examinations were performed in 970 patients (54% non-MR conditional systems, 39% defibrillators, 15% pacing-dependent) with 2268 leads. There were no lead-related adverse clinical events, and no clinically significant immediate or late lead parameter changes following MRI in either MR-conditional or non-MR conditional leads. Small reductions in atrial and right ventricular sensed amplitudes and impedances were similar between groups, with no difference in the proportion of leads with parameter changes greater than pre-defined thresholds (7.1%, 95% confidence interval: 6.1–8.3). // Conclusions: There was no increased risk of MRI in patients with non-MR conditional pacemaker or defibrillator leads when following recommended protocols. Standardizing MR conditions for all leads would significantly improve access to MRI by enabling patients to be scanned in non-specialist centres, with no discernible incremental risk

Self-employment in an equilibrium model of the labor market

Self-employed workers account for between 8% and 30% of participants in the labor markets of OECD countries, Blanch ower (2004). This paper develops and estimates a general equilibrium model of the labor market that accounts for this sizable proportion. The model incorporates self-employed workers, some of whom hire paid employees in the market. Employment rates and earnings distributions are determined endogenously and are estimated to match their empirical counterparts. The model is estimated using the British Household Panel Survey (BHPS). The model is able to estimate nonpecuniary amenities associated with employment in di erent labor market states, accounting for both different employment dynamics within state and the misreporting of earnings by self-employed workers. Structural parameter estimates are then used to assess the impact of an increase in the generosity of unemployment benefits on the aggregate employment rate. Findings suggest that modeling the self-employed, some of whom hire paid employees implies that small increases in unemployment benefits leads to an expansion in aggregate employment

The retirement behaviour of the self-employed in Britain

We analyze the retirement behaviour of older self-employed workers, using a life cycle framework and a multinomial logit model of dynamic employment and retirement choices. Using data from the two-wave Retirement Survey, we find that greater actual or potential earnings decrease the probability of retirement among the self-employed. In contrast to employees, none of gender, health or family circumstances appear to affect self-employed retirement decisions. The dynamic analysis reveals that relatively few employees and virtually no retirees switch into self-employment in later life. The switches that do occur are motivated less by attempts to use self-employment as a bridge job or 'stepping stone' to full retirement, than by self-employment being a last resort for less affluent workers with job histories of weak attachment to the labour market. We compare self-employed and employee retirement behaviour and discuss the policy implications of our results.

Basic and reductive sulfone-directed ring-opening reactions of difluorinated oxa[2.2.1]bicycloheptanes

Phenylsulfenyl chloride reacts with racemic endo Diels-Alder adduct 4 (DEC ) CONEt2) to afford lactone 8, which can be reduced and protected in a series of high-yielding steps. Key sulfone 10 can be ring opened under strong base conditions to afford vinyl sulfone 11. Attempted desulfonation resulted in the formation of a monofluoroalkene, but a direct desulfonation/eliminative ring opening with strain relief delivered highly functionalized monocyclic species 16