The Disparities in the Electrogram Voltage Measurement During Atrial Fibrillation and Sinus Rhythm

Unipolar Electrogram Voltage in Patients with Atrial Fibrillation . Introduction: The peak electrogram voltage is a typical metric applied at each site for voltage mapping. However, the peak amplitude depends on the direction and complexity of the wavefront propagation. The root‐mean‐square (RMS) measure of the amplitude is a temporal integral that represents the steady‐state value. The objective of this study was to investigate the disparities between the electrogram voltage during SR and AF by using 2 recording modalities: the conventional peak voltage and an RMS measurement. Methods and Results: This study enrolled 20 patients (age = 59 ± 13) with paroxysmal AF undergoing catheter ablation guided by Ensite array. The unipolar electrogram voltage during SR and AF (7 seconds in duration) was obtained from the same sites, and labeled by the 3‐dimensional (3D) geometry. Overall 1,200 electrograms were analyzed from equally distributed mapping sites in the left atrium. A point‐by‐point comparison of the unipolar peak negative voltage (PNV) showed less agreement (Bland and Altman test: 10.4% outside 2 standard deviations, and intraclass correlation coefficient [ICC]= 0.64). The RMS voltage demonstrated agreement between SR and AF for all sites (BA test: 5.9% of the sites, and the ICC = 0.81). The probability of predicting a low‐voltage during AF using the voltage during SR was significantly lower when using the PNV measurement compared to that when using the RMS voltage (15% vs 61%, P < 0.05). Conclusion: The peak electrogram unipolar voltage during AF did not represent the voltage during SR. The RMS amplitude may be an alternative metric for voltage mapping to characterize the myocardial substrate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 393–398, April 2010)     

Ring 14 chromosome presenting as early-onset isolated partial epilepsy

We report four infants (two males, two females) with ring 14 chromosome presenting with early-onset partial epilepsy. The first seizure occurred between 3 and 6 months (3, 3, 4, and 6mo respectively). In all four cases, diagnosis was based on early focal seizures, rather than on psychomotor retardation or morphological features, which were not prominent at seizure onset. Moreover, despite the young age of the patients and the high frequency of seizures, neither epileptic spasms nor progression to 'epileptic encephalopathy', such as hypsarrhythmia, were observed. Epilepsy remained partial in these patients. At the most recent follow-up, all four children had slight or mild psychomotor delay, and two of them had moderate non-specific dysmorphic traits. Data from the literature about epilepsy in ring 14 chromosome syndrome were also reviewed. Ring 14 chromosome syndrome may be revealed by isolated, early-onset focal epilepsy suggestive of focal lesions with only mild mental retardation and morphological features at the time of diagnosis. The characteristics of these observations differ from classic ring 14 syndrome, and may enlarge this clinical spectrum. Many unanswered questions remain concerning phenotype–genotype correlation and identification of the potential genes and molecular mechanisms responsible for epilepsy in patients with ring 14 syndrome.     

CONTEMPLATING TOTAL ARTIFICIAL HEART INACTIVATION IN CASES OF FUTILITY

Though currently an experimental technology, there is the potential for implantation of 100,000 total artificial replacement hearts each year in the United States once regulatory approvals are obtained. Although these devices are intended to lengthen life and improve its quality, clinical scenarios can emerge in which the device is no longer serving these goals and termination of life support, including inactivation of the implant, must be contemplated. Although the literature is replete with guidance on the withdrawal of non-implantable therapies, such as dialysis and artificial ventilation, there has been minimal discussion involving the deactivation of implanted therapies. Here, guidance is offered regarding the withdrawal of total artificial heart therapy.     

ELECTIVE INACTIVATION OF TOTAL ARTIFICIAL HEART TECHNOLOGY IN NON-FUTILE SITUATIONS: INPATIENTS,OUTPATIENTS AND RESEARCH PARTICIPANTS

Total artificial heart technology as a potential clinical therapy raises the issue of elective device inactivation in both futile and non-futile situations. This article explores elective device inactivation in non-futile situations. In reply to such requests for inactivation, the medical team should reflect on the individual's decision-making capacity, the clinical appropriateness of the therapy, and the setting of the request (clinical research vs. clinical practice). A decision-making flowchart is presented as a guide for managing inactivation requests. In the research setting, current U.S. federal regulations are murky as to the matter of study withdrawal made by participants who lack decision-making capacity. This compared with clear legal and ethical approaches in the non-research setting (clinical practice).     

Harms and Responsibilities Associated with Battery‐Operated Implants (BOI): Who Controls Postmortem Explantation?

The postmortem issues raised by battery‐operated implants (BOI) are complex and issues of consent, setting (clinical vs research), and environmental risks have received little attention in bioethics literature. Analyzing the issues, the following are argued: (1) Patients receiving BOIs should sign a consent form that includes a requirement for postmortem explant of the device; (2) BOI consent forms should require the explanted devices be returned to their manufacturers for Returned Product Analysis; (3) Failure to explant and analyze devices from the research setting fails the research goal of generation of knowledge for the benefit of future patients; (4) Failure to explant and analyze devices from the clinical setting allows product defects to be potentially hidden from patients, families, clinicians, manufacturers, and regulatory agencies; (5) Bodies buried with BOIs potentially harm the environment; (6) Religious or philosophical objections to autopsy should not supersede the duty to explant and analyze BOIs; (7) The concepts herein for BOIs could potentially extend to non‐BOI if the device has failure modes that can lead to a potentially life‐threatening event or can cause permanent debilitating health issues, and the burial or cremation of the device poses environmental harm. In these situations, neither the patient (premortem) nor family (postmortem) should have the right to refuse explant. (PACE 2013; 36:7–10)     

齐墩果酸固体分散体的制备及体外溶出度测定

目的：为了提高制剂中齐墩果酸(OIA)的溶出度。方法：选择聚乙烯吡咯烷酮(PVPk-30)、泊洛沙姆188两种载体,用溶剂法制备齐墩果酸固体分散体;建立HPLC法检测固体分散体的体外溶出度;并进行差热分析和红外光谱测定以鉴别药物在载体中的存在状态和药物与载体之间的相互作用。结果：使用HPLC法测定OLA的溶出量,结果准确可靠、稳定、无载体的干扰。制备成固体分散体能显著地提高OLA的体外溶出速度;PVPk-30载体的固体分散体溶出速度快于泊洛沙姆载体的固体分散体溶出速度。结论：可以选择PVPk-30作为载体制备OLA固体分散体有效地提高OLA溶出速度。     

基于不同湍流模型的离心泵叶轮内部流场分析

基于计算流体力学数值模拟技术,对一个低比转速离心泵叶轮内部流场流动情况进行分析研究。分别采用4种湍流模型：标准k ε模型、RNG k ε模型、Realizable k ε模型和雷诺应力模型（RSM）及SIMPLE 算法,对不同湍流模型及不同工况下的扬程预测曲线,比较计算时间的差别,在此基础上,比较不同模型在设计工况下的流场,并与实验结果进行了对比分析。     

BLOOD DISTRIBUTION OF TENOXICAM IN HUMANS: A PARTICULAR HSA DRUG INTERACTION

Blood binding of tenoxicam was studied in vitro by equilibrium dialysis. Isolated human plasma proteins and blood cells were checked, and the distribution of the bound form was then calculated. The results showed that tenoxicam is mainly bound to HSA and that binding percentages are not different when measured in plasma (98.4%) and in an HSA solution at physiological concentration (704 microM, 98.15%). In these conditions, within the range of 1-150 microM, the tenoxicam binding percentage remained constant, evidence of a nonsaturable process. When a lower HSA concentration (10 microM) was used, the binding parameters of the tenoxicam interaction were calculated by using the same equilibrium dialysis data, by 3 methods of analysis- a stoichiometric method and site-oriented methods, fixing or not the number of HSA binding sites (n) as integer values. The best fit was observed with the first method, suggesting that two main interactions occurred. The site-oriented method gave lesser fits, the better being observed when n was not fixed. Its value, 1.77, suggest the possibility of two binding sites, one of them not preformed. The effects of known markers of site I, warfarin and apazone, of site II, diazepam and ibuprofen and of palmitic acid showed that tenoxicam is bound simultaneously to both sites I and II. The binding capacity of site I for tenoxicam is enhanced by diazepam: as this compound alone is bound to site II, this result suggests that the two HSA binding sites are not independent.     

Emotional and behavioural problems experienced by children living in single-parent families: A pilot study

This study compared the prevalence of emotional and behavioural problems experienced by 10-11 year old and 14-15 year old children living in single-parent and two-parent families in South Australia. The 10-11 year old male children living in single-parent families were found to have significantly more emotional and behavioural problems than 10-11 year old male children living in two-parent families. In particular, the younger male children living in single-parent families experienced more externalizing behaviour problems than younger male children living in two-parent families. It is suggested that paediatricians and general practitioners need to be aware of children who are at particular risk for developing emotional and behavioural problems, and the approaches which may be employed to provide help.     

Adaptation of the gastric epithelium to injury is maintained in vitro and is associated with increased TGF-α expression

Adaptation is the name given to the progressive decrease in gastric mucosal damage following repeated dosing with damaging agents. This study aimed to determine whether adaptation is an intrinsic property of the gastric epithelium and the role in the development of this process of TGFα. Rats were given either one or six daily doses of 10 mg/kg diclofenac or six daily doses of vehicle only (1% methylcellulose). On the 7th day, antral mucosa was taken for organ culture and loaded with [⁵¹Cr]. Explants were challenged with ethanol and damage quantified by [⁵¹Cr] release. In a separate experiment, rats were dosed as above and the gastric mucosa was extracted and TGFα quantified by RIA. The rate of [⁵¹Cr] release was significantly lower after ethanol injury in explants from rats previously adapted to diclofenac (9.2±2.5%) compared with those exposed to a single damaging dose of diclofenac (25.9±3.5%) or vehicle only (26.4±3.3%; P < 0.01; anova ). The concentration of TGFα was significantly higher in the gastric epithelium of rats adapted to diclofenac than other groups (P < 0.05; t-test). Cross adaptation of the gastric mucosa to injury has therefore been demonstrated in antral mucosal explants in organ culture while TGFα peptide expression is elevated in the adapted gastric mucosa. These findings suggest that adaptation is an inherent property of the gastric epithelium and it is likely that TGFα may play a role in its maintenance.