A case of biventricular pacing with a spike on T-wave caused by the algorithm maintaining biventricular pacing rate

AbstractCardiac-resynchronization therapy (CRT) improves the cardiac function of patients with left ventricular (LV) dyssynchrony. Maintenance of the biventricular pacing rate is very important in managing the hemodynamics in patients implanted with CRT devices. A low biventricular pacing rate, for example, in cases with atrial fibrillation or rapid intrinsic atrioventricular (AV) conduction, decreases the benefits of CRT. The LUMAX HF-T 540 device series (BIOTRONIK, Berlin, Germany) has a LV-triggered pace algorithm, which allows biventicular pacing rates to be maintained even during rapid intrinsic rhythms caused by shortened AV conduction and/or premature ventricular contraction (PVC) occurring in the right ventricle. We encountered a case of CRT device implantation with a defibrillator wherein this triggered pace algorithm caused a spike on T-wave due to T-wave oversensing. By remote monitoring, we were also able to determine that the T-wave oversensing was due to a PVC. The LUMAX 540 series allows for changes in the sensing threshold and filter settings of the device, which facilitated the elimination of T-wave oversensing in this case

Visualization of Painful Experiences Believed to Trigger the Activation of Affective and Emotional Brain Regions in Subjects with Low Back Pain

In the management of clinical low back pain (LBP), actual damage to lower back areas such as muscles, intervertebral discs etc. are normally targeted for therapy. However, LBP may involve not only sensory pain, but also underlying affective pain which may also play an important role overall in painful events. Therefore we hypothesized that visualization of a painful event may trigger painful memories, thus provoking the affective dimension of pain. The present study investigated neural correlates of affect processing in subjects with LBP (n = 11) and subjects without LBP (n = 11) through the use of virtual LBP stimuli. Whole brain functional magnetic resonance imaging (MRI) was performed for all subjects while they were shown a picture of a man carrying luggage in a half-crouching position. All subjects with LBP reported experiencing discomfort and 7 LBP subjects reported experiencing pain. In contrast to subjects without LBP, subjects with LBP displayed activation of the cortical area related to pain and emotions: the insula, supplementary motor area, premotor area, thalamus, pulvinar, posterior cingulate cortex, hippocampus, fusiform, gyrus, and cerebellum. These results suggest that the virtual LBP stimuli caused memory retrieval of unpleasant experiences and therefore may be associated with prolonged chronic LBP conditions

Augmented single-unit muscle sympathetic nerve activity in heart failure with chronic atrial fibrillation

Atrial fibrillation (AF) is a common complication in heart failure (HF) patients. However, it remains unclear whether irregular ventricular response patterns induced by AF increase sympathetic nerve activity. We measured resting multi- and single-unit muscle sympathetic nerve activity (MSNA) in 21 age-matched HF patients with chronic AF (n= 11) rhythm or sinus rhythm (SR, n= 10). The multi-unit MSNA, which was expressed as total activity, was similar between HF + AF patients and HF + SR patients. However, the single-unit MSNA in HF + AF patients was significantly greater than that in HF + SR patients (62 ± 9 spikes min -1vs. 42 ± 4 spikes min -1, P < 0.05). Moreover, the incidence of multiple firing of single-unit MSNA within a given burst was augmented in HF + AF patients as compared with HF + SR patients (48 ± 8%vs. 26 ± 3%, P < 0.01). A significant negative relationship was observed between the reduced diastolic pressure induced by a prolonged cardiac interval in AF subjects and single-unit MSNA frequency within one cardiac interval in each HF + AF subject. The firing characteristics of single-unit MSNA were different between HF patients with AF and HF patients with SR; particularly, those with a prolonged long RR interval showed multiple firings of single-unit MSNA. These findings suggest that AF per se leads to the instantaneous augmentation of single-unit MSNA induced by decreased diastolic pressure, which might partially contribute to disease progression in HF patients. © 2012 The Authors. The Journal of Physiology © 2012 The Physiological Society

カルバモイルメチルラジカルの環化反応と天然物合成への応用

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学

Altered Interaction Between Plasminogen Activator Inhibitor Type 1 Activity and Sympathetic Nerve Activity With Aging

金沢大学大学院医学系研究

表面波探査手法による地下S波速度構造推定の高精度化

京都大学0048新制・課程博士博士(工学)甲第18257号工博第3849号新制||工||1590(附属図書館)31115京都大学大学院工学研究科都市社会工学専攻(主査)教授 松岡 俊文, 教授 清野 純史, 教授 小池 克明学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

Multimode inversion with amplitude response of surface waves in the spatial autocorrelation method

Microtremors are usually analysed without any consideration of the higher modes of surface waves. However, recent studies have demonstrated that higher modes contain useful information for improving the inverted S-wave velocity model. In this study, we propose two inversion methods that consider higher modes by using the amplitude response of each mode, which can avoid mode misidentification in the spatial autocorrelation (SPAC) method. One method is to compare the observed phase velocities by the extended spatial autocorrelation (ESPAC) method with the effective phase velocities calculated from theoretical dispersion curves and the amplitude responses of each mode. In the other method, SPAC coefficients are fit directly by comparing theoretical SPAC coefficients determined from dispersion curves and amplitude responses with the observed ones. The latter, direct-fitting approach is much simpler than the method using effective phase velocities. To investigate the effectiveness of these methods, a simulation study was conducted. Simulated microtremors that included higher modes were successfully inverted by the proposed multimode methods. The observed phase velocities and SPAC coefficients determined from field data were also consistent with theoretical ones constructed by the proposed methods except at low frequencies. The inversion using effective phase velocities required prior information about an infinite half-space to obtain a better S-wave velocity model whereas the direct-fitting inversion worked well without prior information, suggesting the direct-fitting method is more robust than the method using effective phase velocities. We conclude that our proposed inversion methods are effective for estimating the S-wave velocity structure even if higher modes of surface waves are predominant in observed microtremors

Characteristics of the horizontal component of Rayleigh waves in multimode analysis of surface waves

In surface-wave analysis, S-wave velocity estimations can be improved by the use of higher modes of the surface waves. The vertical component of P-SV waves is commonly used to estimate multimode Rayleigh waves, although Rayleigh waves are also included in horizontal components of P-SV waves. To demonstrate the advantages of using the horizontal components of multimode Rayleigh waves, we investigated the characteristics of the horizontal and vertical components of Rayleigh waves. We conducted numerical modeling and field data analyses rather than a theoretical study for both components of Rayleigh waves. As a result of a simulation study, we found that the estimated higher modes have larger relative amplitudes in the vertical and horizontal components as the source depth increases. In particular, higher-order modes were observed in the horizontal component data for an explosive source located at a greater depth. Similar phenomena were observed in the field data acquired by using a dynamite source at 15-m depth. Sensitivity analyses of dispersion curves to S-wave velocity changes revealed that dispersion curves additionally estimated from the horizontal components can potentially improve S-wave velocity estimations. These results revealed that when the explosive source was buried at a greater depth, the horizontal components can complement Rayleigh waves estimated from the vertical components. Therefore, the combined use of the horizontal component data with the vertical component data would contribute to improving S-wave velocity estimations, especially in the case of buried explosive source signal