Safety of repetitive nerve stimulation in patients with cardiac implantable electronic devices

Introduction: Pacemakers and implantable cardioverter-defibrillators (ICDs) are vulnerable to inappropriate sensing of electromagnetic interference (EMI), such as from nerve conduction studies. We conducted a prospective study to assess the safety of repetitive nerve stimulation (RNS). Methods: Fourteen patients undergoing insertion of 10 ICDs and 4 pacemakers under general anesthesia received RNS of the median, axillary, and spinal accessory nerves at 2 HZ and 50 HZ . We recorded detection of EMI and whether or not this resulted in an arrhythmia diagnosis or change in pacing output. Results: EMI was visible in 2 ICDs, without spurious tachyarrhythmia detection. EMI was observed in 3 of the 4 pacemakers, which led to pacing inhibition and a pause in 2, both of which were programmed to a unipolar sensing configuration. Conclusions: RNS is safe in patients with ICDs. In pacemaker patients, RNS appears safe during bipolar sensing, but caution is recommended in pacemaker patients with unipolar sensing. Muscle Nerve 47: 840–844, 2013     

A systematic review and meta‐analysis of clinical variables used in Huntington disease research

Treatment effect in Huntington disease (HD) clinical trials has relied on primary outcome measures such as total motor score or functional rating scales. However, these measures have limited sensitivity, particularly in pre‐ to early stages of the disease. We performed a systematic review of HD clinical studies to identify endpoints that correlate with disease severity. Using standard HD keywords and terms, we identified 749 published studies from 1993 to 2011 based on the availability of demographic, biochemical, and clinical measures. The average and variability of each measure was abstracted and stratified according to pre‐far, pre‐close, early, mild, moderate, and severe HD stages. A fixed‐effect meta‐analysis on selected variables was conducted at various disease stages. A total of 1,801 different clinical variables and treatment outcomes were identified. Unified Huntington Disease Rating Scale (UHDRS) Motor, UHDRS Independence, and Trail B showed a trend toward separation between HD stages. Other measures, such as UHDRS Apathy, Verbal Fluency, and Symbol Digit, could only distinguish between pre‐ and early stages of disease and later stages, whereas other measures showed little correlation with increasing HD stages. Using cross‐sectional data from published HD clinical trials, we have identified potential endpoints that could be used to track HD disease progression and treatment effect. Longitudinal studies, such as TRACK‐HD, are critical for assessing the value of potential markers of disease progression for use in future HD therapeutic trials. A list of variables, references used in this meta‐analysis, and database is available at http://www.cmmt.ubc.ca/research/investigators/leavitt/publications . © 2013 International Parkinson and Movement Disorder Society     

Access to Cytotoxic Medicines by Children With Cancer: A Focus on Low and Middle Income Countries

Background

The Essential Medicines Working Group of the International Society of Pediatric Oncology (SIOP) has proposed a list of antineoplastic drugs that should be available in low and middle income countries.

Procedure

Data were extracted on the listing of 18 essential and 8 ancillary antineoplastic medicines in the national essential medicines lists (NEMLs) or national reimbursable medicines lists (NRMLs) of 135 countries with gross national income (GNI) per capita of less than US $25,000. Correlations between numbers of medicines listed and GNI per capita, annual government health expenditure (AGHE) per capita, and the number of physicians per million people were examined.

Results

Listing of the 18 essential antineoplastic drugs ranged from 27% (thioguanine) to 95% (methotrexate). The median number of medicines listed was 7 (0–18) in low income countries (n = 26) and 14 in lower‐middle (n = 42), upper‐middle (n = 44), and high income countries (n = 20). For the ancillary eight medicines, the median was one (0–8) across the 135 countries. Correlations with GNI per capita (r = 0.17, P = 0.0266) and physician density (r = 0.25, P = 0.0017) were statistically significant; not so for AGHE per capita (r = 0.00, P = 0.5000).

Conclusions

There was large variability within income groups in numbers of antineoplastic agents identified as essential in NEMLs and NRMLs. While not a direct measure of availability, listing is an important step, guiding procurement for the public sector. These results focus attention on deficits in NEMLs and NMRLs as a step to improving access to effective antineoplastic medicines for cancers in children in low and middle income countries. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc.     

Lack of efficacy of high-dose verapamil in preventing brain damage in baboons and pigs after prolonged partial cerebral ischemia

There has been mounting speculation that calcium antagonists may be useful in reducing or preventing brain damage after cardiopulmonary resuscitation. To test the clinical usefulness of these agents in averting such damage, high-dose verapamil was administered to baboons and pigs after partial cerebral ischemia for varying periods of time. In Group A baboons and pigs, the major aortic branches supplying the carotid and vertebral circulations were clamped for periods ranging from 15 to 150 minutes, and neurological recovery was observed. In Group B, verapamil hydrochloride 0.7 mg/kg was given by intravenous infusion after similar periods of arterial occlusion. The administration of verapamil did not lead to any clinically improved neurological outcome. The use of verapamil after prolonged periods of partial cerebral ischemia did not improve neurological recovery in baboons and pigs.