Significance of missing telemetered markers in implanted cardioverter-defibrillators

Background: We report three patients with St Jude ICDs (St. Jude Medical, Sylmar, CA, USA) where some aspect of the marker channel was missing. Methods and Results: Two cases were caused by the simultaneous occurrence of two distinct cardiac or device events that affected the proper delivery of markers by the telemetry system. Inability of the devices to sequentially process these events resulted in incomplete transmission of telemetry data to the programmers and caused missing markers in the telemetry recordings. In the third case, sensed atrial interference resulted in a short period of atrial asynchronous pacing, which prevented the delivery of a sensed atrial marker coincident with an atrial electrogram. This atrial electrogram by virtue of its timing would have otherwise been sensed outside the atrial refractory period. Conclusion: The perplexing recordings of the three patients should not be interpreted as representing true pacemaker malfunction. PACE 2012; 35:409–415)     

Wireless multi-channel single unit recording in freely moving and vocalizing primates

The ability to record well-isolated action potentials from individual neurons in naturally behaving animals is crucial for understanding neural mechanisms underlying natural behaviors. Traditional neurophysiology techniques, however, require the animal to be restrained which often restricts natural behavior. An example is the common marmoset (Callithrix jacchus), a highly vocal New World primate species, used in our laboratory to study the neural correlates of vocal production and sensory feedback. When restrained by traditional neurophysiological techniques marmoset vocal behavior is severely inhibited. Tethered recording systems, while proven effective in rodents pose limitations in arboreal animals such as the marmoset that typically roam in a three-dimensional environment. To overcome these obstacles, we have developed a wireless neural recording technique that is capable of collecting single-unit data from chronically implanted multi-electrodes in freely moving marmosets. A lightweight, low power and low noise wireless transmitter (headstage) is attached to a multi-electrode array placed in the premotor cortex of the marmoset. The wireless headstage is capable of transmitting 15 channels of neural data with signal-to-noise ratio (SNR) comparable to a tethered system. To minimize radio-frequency (RF) and electro-magnetic interference (EMI), the experiments were conducted within a custom designed RF/EMI and acoustically shielded chamber. The individual electrodes of the multi-electrode array were periodically advanced to densely sample the cortical layers. We recorded single-unit data over a period of several months from the frontal cortex of two marmosets. These recordings demonstrate the feasibility of using our wireless recording method to study single neuron activity in freely roaming primates.     

Development and validation of an algorithm for the study of sleep using a biometric shirt in young healthy adults

Portable polysomnography is often too complex and encumbering for recording sleep at home. We recorded sleep using a biometric shirt (electrocardiogram sensors, respiratory inductance plethysmography bands and an accelerometer) in 21 healthy young adults recorded in a sleep laboratory for two consecutive nights, together with standard polysomnography. Polysomnographic recordings were scored using standard methods. An algorithm was developed to classify the biometric shirt recordings into rapid eye movement sleep, non‐rapid eye movement sleep and wake. The algorithm was based on breathing rate and heart rate variability, body movement, and included a correction for sleep onset and offset. The overall mean percentage of agreement between the two sets of recordings was 77.4%; when non‐rapid eye movement and rapid eye movement sleep epochs were grouped together, it increased to 90.8%. The overall kappa coefficient was 0.53. Five of the seven sleep variables were significantly correlated. The findings of this pilot study indicate that this simple portable system could be used to estimate the general sleep pattern of young healthy adults.     

Declining Ring-necked Pheasants in the Klamath Basin, California: I. Insecticide Exposure

A study of organophosphorus (OP) insecticide exposure was conducted on a declining population of ring-necked pheasants (Phasianus colchicus) associated with agricultural lands at Tule Lake National Wildlife Refuge (TLNWR) during the summers of 1990–92. Findings at TLNWR were compared with a nearby pheasant population at Lower Klamath National Wildlife Refuge (LKNWR) not subjected to intensive farming or OP insecticide applications. Direct toxicity of anticholinesterase (antiChE) compounds (in this case methamidophos) killed 2 young pheasants (91 and 92% brain acetylcholinesterase [AChE] inhibition), but no deaths of adult radio-equipped hens were ascribed to direct insecticide intoxication. However, within 20 days postspray of OP insecticides, 68% (28 of 41) of the adult pheasants collected at TLNWR were exposed to antiChE insecticides, and exhibited brain AChE inhibition of 19–62%, with 15% (6 of 41) showing >55% brain AChE inhibition. The lack of radio-equipped hens dying was unexpected because >50% brain AChE inhibition has been frequently used as a diagnostic tool for evaluating cause of death from antiChE insecticides. No young were radio-equipped, so the extent of the effects of insecticide exposure on the survivorship of young was unknown. It is concluded that insecticide exposure was not the major factor impacting the pheasant population (see Grove et al., in press), although some young were acutely intoxicated. However, the loss of insects killed by insecticide use may have contributed to food shortages of young pheasants, indirectly influencing survival.     

Bladder telemetry: A new approach to evaluate micturition behavior under physiological and inflammatory conditions

Aims

To establish a new approach to cystometry using telemetry in conscious rats and to use this technique to determine the role of conscious decision making processes with respect to the initiation of voiding in physiological, inflammatory, and painful conditions.

Methods

The pressure transducer of a telemetric transmitter was implanted in the dome of the urinary bladder. After a recovery period of at least 1 month, several investigations of urodynamic parameters were performed after diuresis activation by a pulse of furosemide. The model was characterized by tolterodine and mirabegron under physiological conditions and same animals were reused to evaluate the modification of the voiding pattern under bladder inflammation induced by cyclophosphamide.

Results

The quality of traces and measurement of parameters recorded telemetrically were comparable to those with conventional cystometry. Furosemide induced a reproducible transient increase of urine production and a series of voids that persisted for 60 min. Tolterodine reduced the amplitude of micturition contractions although mirabegron was devoid of any effect. Seven hours after injection of CYP, voiding frequency increased significantly and the micturition amplitude contraction was not altered. However, the mean volume voided during individual micturitions and the total voided volume decreased. During a second exposure to furosemide 24H after CYP injection, the micturition pattern returned to control, however, the micturition volume was still lower than in control.

Conclusion

This telemetric model appears to be as accurate as previously described in conscious conventional cystometry, and allows the repeated evaluation of compounds which may modulate the voiding patterns. Neurourol. Urodynam. 36:308–315, 2017. © 2016 The Authors. Neurourology and Urodynamics published by Wiley Periodicals, Inc.     

清醒Beagle犬安全药理心血管遥测系统验证研究

 目的 选用临床上报道的对QT间期延长有影响的2种阳性药和无影响的1种阴性药在符合GLP条件下对心血管遥测系统进行验证。方法 验证研究中,清醒Beagle犬分别静脉注射给予生理盐水(1 mL·kg^-1, iv, n=2)、卡托普利 (3 mg·kg^-1, iv,n=2)、特非那丁(3 mg·kg^-1, iv, n=2) 和索他洛尔 (10 mg·kg^-1, iv,n=2)。DSI遥测系统连续获取给予上述4种供试品后至少24 h数据,数据包括血压、心电图、心率等指标。DSI Ponemah ECG分析程序使用Fridericia心率校正公式对QT间期进行校正。结果 生理盐水对心血管参数没有明显的影响。卡托普利除导致心率显著增加和平均压下降外,对ECG参数无明显影响。特非那丁和索他洛尔在实验设计剂量下导致Beagle犬经心率校正的QT间期(QTcf)显著增加,增加大于10%。结论 实验数据显示,遥测系统能够检测到清醒Beagle犬中心血管功能的相关变化。在符合ICH安全药理S7B指南的条件下,遥测系统可用作药物所致QT间期延长的模型。
     

Effect of peri-modiolar cochlear implant positioning on auditory nerve responses: A neural response telemetry study

Conclusions. There was no evidence that a reduction in current was needed for nerve stimulation as a result of modiolar placement of a cochlear implant. However, modiolus hugging did reduce the spread of excitation for the basal and apical electrodes. This improved stimulation selectivity may result in improved speech discrimination by implant users. Objective. To test the effect of modiolar placement of a cochlear implant on stimulation thresholds, and to confirm whether peri-modiolar electrode placement resulted in the hypothesized reduced spread of excitation. Material and methods. Auditory nerve responses were measured by means of neural response telemetry (NRT) in 14 subjects. All subjects received a Nucleus CI24R(CS) Contour implant. For each subject, the stimulation threshold and response growth rate were determined on all the odd-numbered electrodes, using a masker-and-probe paradigm. In addition, the spatial spread of excitation was measured on electrodes 1, 6, 11, 16 and 20, using a variable-masker paradigm. All NRT measurements were performed intra-operatively, both before and after peri-modular placement of the electrode by removal of surgical stylet. Results. Removal of the stylet had no significant effect on the threshold and growth rate of NRT responses. It caused a reduction in the spread of excitation for electrodes 1, 6 and 20, but not for electrodes 11 and 16.     

人工耳蜗术后编程中神经反应遥测阈值及行为T值的比较分析

目的 了解人工耳蜗术后神经反应遥测(NRT)阈值的变化,NRT与行为T值之间的相关性,以及长期行为T值的变化,为人工耳蜗植入术后的患儿编程提供帮助。 方法 20例接受Nucleus CI24R型多导人工耳蜗植入的患儿,在开机时及6个月调试时对1、11、20号电极进行NRT阈值测试,通过NRT值进行电子耳蜗程序设置;开机后1年和2年对患儿进行行为T值测试,并设置程序;收集开机时及6个月的NRT值分别与1年及2年的行为T值比较。 结果 1号电极开机时和6个月时NRT相互比较差异无统计学意义,11号和22号电极开机时和6个月时NRT差异有统计学意义,三对电极1年与2年行为T值差异都无统计学意义;开机时NRT阈值与行为T值的相关关系中:开机时NRT阈值与行为T值只有22号电极呈正相关,其余两电极中无相关关系。6个月NRT阈值与行为T值的相关关系中:1号电极6个月NRT阈值与行为T值均为正相关;22号电极开机6个月NRT值与1年行为T值为正相关,其他无相关关系。 结论 各电极NRT阈值自开机时基本保持稳定,NRT阈值与行为T值部分电极具有相关性,开机时和最初几次调机时患儿不能配合进行行为测试可以选择NRT阈值来参考调试耳蜗;1年和2年的行为T值也基本稳定,说明患儿术后1年能较好配合行为T值测试,对于配合较好者的患儿可以适当延长调试时间。     

Effects of telemetry implantation surgery on blood pressure and its underlying mechanism

Objective. This study aimed to investigate the effects of radio-telemetry implantation surgery on blood pressure (BP) and renin-angiotensin-aldosterone system (RAAS), calcitonin gene-related peptide (CGRP) and endothelin-1 (ET-1) in rats. Methods: Six spontaneously hypertensive rat (SHRs) and six WKY rats successfully implanted telemetry were used as experimental group, while six SHRs and six Wistar-Kyoto (WKY) rats of comparable age, weight and BP free from implantation surgery were used as normal control group. BP in each group was monitored using the tail cuff method; furthermore, the content of PRA-I, PRA-II, ALD and ET-1, CGRP in plasma was measured with the ELISA. Results: After implantation surgery, there was no general strain difference in systolic blood pressure (SBP) and diastolic blood pressure (DBP) in either SHRs or WKY rats. But there was a significant increase in renin and a suppression of the difference in angiotensin and aldosterone in SHRs and WKY rats. CGRP, ET-1 showed an overall decrease in SHRs and WKY rats. Conclusion: These results indicated that although radio-telemetry is regarded as an efficient and reliable technology for measuring BP, we must pay attention to the influence of the operation itself on BP regulators. After the implantation surgery, decrease in arterial BP or decrease in circulating blood volume might stimulate the secretion of renin, and with the increase of BP and local blood flow, the level of CGRP was decreased. And the decrease of ET-1 may be a kind of protective suppression.