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1.
Indian Pacing Electrophysiol J ; 24(3): 140-146, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38657736

RESUMO

BACKGROUND: Left bundle branch pacing (LBBP) is a novel physiological pacing technique which may serve as an alternative to cardiac resynchronization therapy (CRT) by biventricular pacing (BVP). This study assessed ventricular activation patterns and echocardiographic and clinical outcomes of LBBP and compared this to BVP. METHODS: Fifty consecutive patients underwent LBBP or BVP for CRT. Ventricular activation mapping was obtained by ultra-high-frequency ECG (UHF-ECG). Functional and echocardiographic outcomes and hospitalization for heart failure and all-cause mortality after one year from implantation were evaluated. RESULTS: LBBP resulted in greater resynchronization vs BVP (QRS width: 170 ± 16 ms to 128 ± 20 ms vs 174 ± 15 to 144 ± 17 ms, p = 0.002 (LBBP vs BVP); e-DYS 81 ± 17 ms to 0 ± 32 ms vs 77 ± 18 to 16 ± 29 ms, p = 0.016 (LBBP vs BVP)). Improvement in LVEF (from 28 ± 8 to 42 ± 10 percent vs 28 ± 9 to 36 ± 12 percent, LBBP vs BVP, p = 0.078) was similar. Improvement in NYHA function class (from 2.4 to 1.5 and from 2.3 to 1.5 (LBBP vs BVP)), hospitalization for heart failure and all-cause mortality were comparable in both groups. CONCLUSIONS: Ventricular dyssynchrony imaging is an appropriate way to gain a better insight into activation patterns of LBBP and BVP. LBBP resulted in greater resynchronization (e-DYS and QRS duration) with comparable improvement in LVEF, NYHA functional class, hospitalization for heart failure and all-cause mortality at one year of follow up.

2.
Epilepsia ; 64(4): 962-972, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36764672

RESUMO

OBJECTIVE: High-frequency oscillations are considered among the most promising interictal biomarkers of the epileptogenic zone in patients suffering from pharmacoresistant focal epilepsy. However, there is no clear definition of pathological high-frequency oscillations, and the existing detectors vary in methodology, performance, and computational costs. This study proposes relative entropy as an easy-to-use novel interictal biomarker of the epileptic tissue. METHODS: We evaluated relative entropy and high-frequency oscillation biomarkers on intracranial electroencephalographic data from 39 patients with seizure-free postoperative outcome (Engel Ia) from three institutions. We tested their capability to localize the epileptogenic zone, defined as resected contacts located in the seizure onset zone. The performance was compared using areas under the receiver operating curves (AUROCs) and precision-recall curves. Then we tested whether a universal threshold can be used to delineate the epileptogenic zone across patients from different institutions. RESULTS: Relative entropy in the ripple band (80-250 Hz) achieved an average AUROC of .85. The normalized high-frequency oscillation rate in the ripple band showed an identical AUROC of .85. In contrast to high-frequency oscillations, relative entropy did not require any patient-level normalization and was easy and fast to calculate due to its clear and straightforward definition. One threshold could be set across different patients and institutions, because relative entropy is independent of signal amplitude and sampling frequency. SIGNIFICANCE: Although both relative entropy and high-frequency oscillations have a similar performance, relative entropy has significant advantages such as straightforward definition, computational speed, and universal interpatient threshold, making it an easy-to-use promising biomarker of the epileptogenic zone.


Assuntos
Eletroencefalografia , Epilepsia , Humanos , Entropia , Eletroencefalografia/métodos , Epilepsia/diagnóstico , Epilepsia/cirurgia , Eletrocorticografia/métodos , Biomarcadores
3.
Eur Heart J Suppl ; 25(Suppl E): E17-E24, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37234235

RESUMO

Biventricular pacing (Biv) and left bundle branch area pacing (LBBAP) are methods of cardiac resynchronization therapy (CRT). Currently, little is known about how they differ in terms of ventricular activation. This study compared ventricular activation patterns in left bundle branch block (LBBB) heart failure patients using an ultra-high-frequency electrocardiography (UHF-ECG). This was a retrospective analysis including 80 CRT patients from two centres. UHF-ECG data were obtained during LBBB, LBBAP, and Biv. Left bundle branch area pacing patients were divided into non-selective left bundle branch pacing (NSLBBP) or left ventricular septal pacing (LVSP) and into groups with V6 R-wave peak times (V6RWPT) < 90 ms and ≥ 90 ms. Calculated parameters were: e-DYS (time difference between the first and last activation in V1-V8 leads) and Vdmean (average of V1-V8 local depolarization durations). In LBBB patients (n = 80) indicated for CRT, spontaneous rhythms were compared with Biv (39) and LBBAP rhythms (64). Although both Biv and LBBAP significantly reduced QRS duration (QRSd) compared with LBBB (from 172 to 148 and 152 ms, respectively, both P < 0.001), the difference between them was not significant (P = 0.2). Left bundle branch area pacing led to shorter e-DYS (24 ms) than Biv (33 ms; P = 0.008) and shorter Vdmean (53 vs. 59 ms; P = 0.003). No differences in QRSd, e-DYS, or Vdmean were found between NSLBBP, LVSP, and LBBAP with paced V6RWPTs < 90 and ≥ 90 ms. Both Biv CRT and LBBAP significantly reduce ventricular dyssynchrony in CRT patients with LBBB. Left bundle branch area pacing is associated with more physiological ventricular activation.

4.
Sensors (Basel) ; 22(5)2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35271057

RESUMO

Pulse wave velocity is a commonly used parameter for evaluating arterial stiffness and the overall condition of the cardiovascular system. The main goal of this study was to establish a methodology to test and validate multichannel bioimpedance as a suitable method for whole-body evaluations of pulse waves. We set the proximal location over the left carotid artery and eight distal locations on both the upper and lower limbs. In this way, it was possible to simultaneously evaluate pulse wave velocity (PWV) in the upper and lower limbs and in the limbs via four extra PWV measurements. Data were acquired from a statistical group of 220 healthy subjects who were divided into three age groups. The data were then analysed. We found a significant dependency of aortic PWV on age in those values measured using the left carotid as the proximal. PWV values in the upper and lower limbs were found to have no significant dependency on age. In addition, the PWV in the left femoral artery shows comparable values to published already carotid-femoral values. Those findings prove the reliability of whole-body multichannel bioimpedance for pulse wave velocity evaluation and provide reference values for whole-body PWV measurement.


Assuntos
Envelhecimento , Análise de Onda de Pulso , Artérias Carótidas , Humanos , Extremidade Inferior , Análise de Onda de Pulso/métodos , Reprodutibilidade dos Testes
5.
Hum Brain Mapp ; 42(17): 5626-5635, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34448523

RESUMO

The degree of response to subthalamic nucleus deep brain stimulation (STN-DBS) is individual and hardly predictable. We hypothesized that DBS-related changes in cortical network organization are related to the clinical effect. Network analysis based on graph theory was used to evaluate the high-density electroencephalography (HDEEG) recorded during a visual three-stimuli paradigm in 32 Parkinson's disease (PD) patients treated by STN-DBS in stimulation "off" and "on" states. Preprocessed scalp data were reconstructed into the source space and correlated to the behavioral parameters. In the majority of patients (n = 26), STN-DBS did not lead to changes in global network organization in large-scale brain networks. In a subgroup of suboptimal responders (n = 6), identified according to reaction times (RT) and clinical parameters (lower Unified Parkinson's Disease Rating Scale [UPDRS] score improvement after DBS and worse performance in memory tests), decreased global connectivity in the 1-8 Hz frequency range and regional node strength in frontal areas were detected. The important role of the supplementary motor area for the optimal DBS response was demonstrated by the increased node strength and eigenvector centrality in good responders. This response was missing in the suboptimal responders. Cortical topologic architecture is modified by the response to STN-DBS leading to a dysfunction of the large-scale networks in suboptimal responders.


Assuntos
Córtex Cerebral/fisiopatologia , Estimulação Encefálica Profunda , Rede Nervosa/fisiopatologia , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia , Desempenho Psicomotor/fisiologia , Núcleo Subtalâmico/fisiopatologia , Idoso , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde
6.
J Cardiovasc Electrophysiol ; 32(5): 1385-1394, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33682277

RESUMO

BACKGROUND: Right ventricular (RV) pacing causes delayed activation of remote ventricular segments. We used the ultra-high-frequency ECG (UHF-ECG) to describe ventricular depolarization when pacing different RV locations. METHODS: In 51 patients, temporary pacing was performed at the RV septum (mSp); further subclassified as right ventricular inflow tract (RVIT) and right ventricular outflow tract (RVOT) for septal inflow and outflow positions (below or above the plane of His bundle in right anterior oblique), apex, anterior lateral wall, and at the basal RV septum with nonselective His bundle or RBB capture (nsHBorRBBp). The timings of UHF-ECG electrical activations were quantified as left ventricular lateral wall delay (LVLWd; V8 activation delay) and RV lateral wall delay (RVLWd; V1 activation delay). RESULTS: The LVLWd was shortest for nsHBorRBBp (11 ms [95% confidence interval = 5-17]), followed by the RVIT (19 ms [11-26]) and the RVOT (33 ms [27-40]; p < .01 between all of them), although the QRSd for the latter two were the same (153 ms (148-158) vs. 153 ms (148-158); p = .99). RV apical capture not only had a longer LVLWd (34 ms (26-43) compared to mSp (27 ms (20-34), p < .05), but its RVLWd (17 ms (9-25) was also the longest compared to other RV pacing sites (mean values for nsHBorRBBp, mSp, anterior and lateral wall captures being below 6 ms), p < .001 compared to each of them. CONCLUSION: RVIT pacing produces better ventricular synchrony compared to other RV pacing locations with myocardial capture. However, UHF-ECG ventricular dysynchrony seen during RVIT pacing is increased compared to concomitant capture of basal septal myocytes and His bundle or proximal right bundle branch.


Assuntos
Ventrículos do Coração , Septo Interventricular , Fascículo Atrioventricular , Estimulação Cardíaca Artificial , Eletrocardiografia , Ventrículos do Coração/diagnóstico por imagem , Humanos , Contração Miocárdica , Septo Interventricular/diagnóstico por imagem
7.
Epilepsia ; 62(5): e70-e75, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33755992

RESUMO

We hypothesized that local/regional properties of stimulated structure/circuitry contribute to the effect of deep brain stimulation (DBS). We analyzed intracerebral electroencephalographic (EEG) recordings from externalized DBS electrodes targeted bilaterally in the anterior nuclei of the thalamus (ANT) in 12 patients (six responders, six nonresponders) with more than 1 year of follow-up care. In the bipolar local field potentials of the EEG, spectral power (PW) and power spectral entropy (PSE) were calculated in the passbands 1-4, 4-8, 8-12, 12-20, 20-45, 65-80, 80-200 and 200-500 Hz. The most significant differences between responders and nonresponders were observed in the BRIDGE area (bipolar recordings with one contact within the ANT and the second contact in adjacent tissue). In responders, PW was significantly decreased in the frequency bands of 65-80, 80-200, and 200-500 Hz (p < .05); PSE was significantly increased in all frequency bands (p < .05) except for 200-500 Hz (p = .06). The local EEG characteristics of ANT recorded after implantation may play a significant role in DBS response prediction.


Assuntos
Núcleos Anteriores do Tálamo/fisiopatologia , Núcleos Anteriores do Tálamo/cirurgia , Estimulação Encefálica Profunda/métodos , Epilepsia Resistente a Medicamentos/fisiopatologia , Epilepsia Resistente a Medicamentos/cirurgia , Eletroencefalografia/métodos , Humanos
8.
J Cardiovasc Electrophysiol ; 31(1): 300-307, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31788894

RESUMO

INTRODUCTION: The present study introduces a new ultra-high-frequency 14-lead electrocardiogram technique (UHF-ECG) for mapping ventricular depolarization patterns and calculation of novel dyssynchrony parameters that may improve the selection of patients and application of cardiac resynchronization therapy (CRT). METHODS: Components of the ECG in sixteen frequency bands within the 150 to 1000 Hz range were used to create ventricular depolarization maps. The maximum time difference between the UHF QRS complex centers of mass of leads V1 to V8 was defined as ventricular electrical dyssynchrony (e-DYS), and the duration at 50% of peak voltage amplitude in each lead was defined as the duration of local depolarization (Vd). Proof of principle measurements was performed in seven patients with left (left bundle branch block) and four patients with right bundle branch block (right bundle branch block) before and during CRT using biventricular and His-bundle pacing. RESULTS: The acquired activation maps reflect the activation sequence under the tested conditions. e-DYS decreased considerably more than QRS duration, during both biventricular pacing (-50% vs -8%) and His-bundle pacing (-77% vs -13%). While biventricular pacing slightly increased Vd, His-bundle pacing reduced Vd significantly (+11% vs -36%), indicating the contribution of the fast conduction system. Optimization of biventricular pacing by adjusting VV-interval showed a decrease of e-DYS from 102 to 36 ms with only a small Vd increase and QRS duration decrease. CONCLUSIONS: The UHF-ECG technique provides novel information about electrical activation of the ventricles from a standard ECG electrode setup, potentially improving the selection of patients for CRT and application of CRT.


Assuntos
Fascículo Atrioventricular/fisiopatologia , Bloqueio de Ramo/terapia , Terapia de Ressincronização Cardíaca , Eletrocardiografia , Insuficiência Cardíaca/terapia , Frequência Cardíaca , Potenciais de Ação , Idoso , Idoso de 80 Anos ou mais , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/fisiopatologia , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Valor Preditivo dos Testes , Estudo de Prova de Conceito , Fatores de Tempo , Resultado do Tratamento , Função Ventricular Esquerda , Função Ventricular Direita
9.
J Neural Transm (Vienna) ; 127(12): 1579-1588, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32965592

RESUMO

Although deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson's disease (PD) is generally a successful therapy, adverse events and insufficient clinical effect can complicate the treatment in some patients. We studied clinical parameters and cortical oscillations related to STN-DBS to identify patients with suboptimal responses. High-density EEG was recorded during a visual oddball three-stimuli paradigm in DBS "off" and "on" conditions in 32 PD patients with STN-DBS. Pre-processed data were reconstructed into the source space and the time-frequency analysis was evaluated. We identified a subgroup of six patients with longer reaction times (RT) during the DBS "on" state than in the DBS "off" state after target stimuli. These subjects had lower motor responsiveness to DBS and decreased memory test results compared to the other subjects. Moreover, the alpha and beta power decrease (event-related desynchronizations, ERD), known as an activation correlate linked to motor and cognitive processing, was also reduced in the DBS "on" condition in these patients. A subgroup of PD patients with a suboptimal response to STN-DBS was identified. Evaluation of RT could potentially serve as a biomarker for responsiveness to STN-DBS.


Assuntos
Estimulação Encefálica Profunda , Doença de Parkinson , Núcleo Subtalâmico , Cognição , Humanos , Doença de Parkinson/terapia , Tempo de Reação
10.
J Electrocardiol ; 63: 159-163, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31324399

RESUMO

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment in patients with heart failure and conduction abnormalities. However, a significant number of patients do not respond to CRT. Currently employed criteria for selection of patients for this therapy (QRS duration and morphology) have several shortcomings. QRS area was recently shown to provide superior association with CRT response. However, its assessment was not fully automated and required the presence of an expert. OBJECTIVE: Our objective was to develop a fully automated method for the assessment of vector-cardiographic (VCG) QRS area from electrocardiographic (ECG) signals. METHODS: Pre-implantation ECG recordings (N = 864, 695 left-bundle-branch block, 589 men) in PDF files were converted to allow signal processing. QRS complexes were found and clustered into morphological groups. Signals were converted from 12­lead ECG to 3­lead VCG and an average QRS complex was built. QRS area was computed from individual areas in the X, Y and Z leads. Practical usability was evaluated using Kaplan-Meier plots and 5-year follow-up data. RESULTS: The automatically calculated QRS area values were 123 ±â€¯48 µV.s (mean values and SD), while the manually determined QRS area values were 116 ±â€¯51 ms; the correlation coefficient between the two was r = 0.97. The automated and manual methods showed the same ability to stratify the population (hazard ratios 2.09 vs 2.03, respectively). CONCLUSION: The presented approach allows the fully automatic and objective assessment of QRS area values. SIGNIFICANCE: Until this study, assessing QRS area values required an expert, which means both additional costs and a risk of subjectivity. The presented approach eliminates these disadvantages and is publicly available as part of free signal-processing software.


Assuntos
Terapia de Ressincronização Cardíaca , Insuficiência Cardíaca , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/terapia , Eletrocardiografia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/terapia , Humanos , Masculino , Resultado do Tratamento , Vetorcardiografia
11.
Ann Neurol ; 82(2): 299-310, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28779553

RESUMO

OBJECTIVE: In the present study, we aimed to investigate depth electroencephalographic (EEG) recordings in a large cohort of patients with drug-resistant epilepsy and to focus on interictal very high-frequency oscillations (VHFOs) between 500Hz and 2kHz. We hypothesized that interictal VHFOs are more specific biomarkers for epileptogenic zone compared to traditional HFOs. METHODS: Forty patients with focal epilepsy who underwent presurgical stereo-EEG (SEEG) were included in the study. SEEG data were recorded with a sampling rate of 25kHz, and a 30-minute resting period was analyzed for each patient. Ten patients met selected criteria for analyses of correlations with surgical outcome: detection of interictal ripples (Rs), fast ripples (FRs), and VHFOs; resective surgery; and at least 1 year of postoperative follow-up. Using power envelope computation and visual inspection of power distribution matrixes, electrode contacts with HFOs and VHFOs were detected and analyzed. RESULTS: Interictal very fast ripples (VFRs; 500-1,000Hz) were detected in 23 of 40 patients and ultrafast ripples (UFRs; 1,000-2,000Hz) in almost half of investigated subjects (n = 19). VFRs and UFRs were observed only in patients with temporal lobe epilepsy and were recorded exclusively from mesiotemporal structures. The UFRs were more spatially restricted in the brain than lower-frequency HFOs. When compared to R oscillations, significantly better outcomes were observed in patients with a higher percentage of removed contacts containing FRs, VFRs, and UFRs. INTERPRETATION: Interictal VHFOs are relatively frequent abnormal phenomena in patients with epilepsy, and appear to be more specific biomarkers for epileptogenic zone when compared to traditional HFOs. Ann Neurol 2017;82:299-310.


Assuntos
Ondas Encefálicas/fisiologia , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletroencefalografia/métodos , Endofenótipos , Epilepsias Parciais/fisiopatologia , Adulto , Epilepsia Resistente a Medicamentos/cirurgia , Epilepsias Parciais/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
13.
J Neural Transm (Vienna) ; 124(7): 841-852, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28389718

RESUMO

This study investigates how complex motor-cognitive activities are processed in the subthalamic nucleus (STN) and internal globus pallidum (GPi), as adverse neuropsychiatric effects may accompany deep brain stimulation (DBS), mainly in Parkinson's disease (PD) and STN-DBS. Dystonia patients with GPi-DBS electrodes (n = 5) and PD subjects (n = 5) with STN-DBS electrodes performed two tasks: (1) copying letters; and (2) writing any letter other than that appearing on the monitor. The cognitive load of the second task was greater than that of the first. Intracranial local field potentials (LFPs) were analysed. A beta power decrease was the main correlate of the enhanced cognitive load during the second task in both structures, with a lateralization to the left side, mainly in the GPi. A gamma power increase linked with the increased cognitive activity was observed only in the STN. Differences were also observed in the theta and alpha bandpasses. Beta ERD reactivity seems to be essential during the processing of complex motor-cognitive tasks, increases with enhanced cognitive effort, and was observed in both the STN and GPi. Oscillatory reactivity to effortful cognitive processing in other frequency bands was less consistent, with differences between the studied nuclei. Lateralization of activity related to cognitive factors was observed mainly in the GPi.


Assuntos
Cognição/fisiologia , Estimulação Encefálica Profunda , Globo Pálido/fisiologia , Núcleo Subtalâmico/fisiologia , Adulto , Idoso , Distonia/fisiopatologia , Distonia/terapia , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia
14.
J Neurophysiol ; 115(6): 3140-5, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27030735

RESUMO

The function and connectivity of human brain is disrupted in epilepsy. We previously reported that the region of epileptic brain generating focal seizures, i.e., the seizure onset zone (SOZ), is functionally isolated from surrounding brain regions in focal neocortical epilepsy. The modulatory effect of behavioral state on the spatial and spectral scales over which the reduced functional connectivity occurs, however, is unclear. Here we use simultaneous sleep staging from scalp EEG with intracranial EEG recordings from medial temporal lobe to investigate how behavioral state modulates the spatial and spectral scales of local field potential synchrony in focal epileptic hippocampus. The local field spectral power and linear correlation between adjacent electrodes provide measures of neuronal population synchrony at different spatial scales, ∼1 and 10 mm, respectively. Our results show increased connectivity inside the SOZ and low connectivity between electrodes in SOZ and outside the SOZ. During slow-wave sleep, we observed decreased connectivity for ripple and fast ripple frequency bands within the SOZ at the 10 mm spatial scale, while the local synchrony remained high at the 1 mm spatial scale. Further study of these phenomena may prove useful for SOZ localization and help understand seizure generation, and the functional deficits seen in epileptic eloquent cortex.


Assuntos
Ondas Encefálicas/fisiologia , Epilepsia do Lobo Temporal/patologia , Hipocampo/fisiopatologia , Adulto , Mapeamento Encefálico , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sono/fisiologia , Análise Espectral , Adulto Jovem
15.
J Electrocardiol ; 49(6): 902-906, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27590215

RESUMO

Ambulatory monitoring represents an effective tool for the assessment of silent and transient myocardial ischemia during routine daily activities. Incidence of silent ischemia can provide important prognostic information about patients with coronary artery disease or acute coronary syndrome, as well as about post-myocardial infarction patients. The current technological progress enables development of powerful and miniaturized wearable devices for Holter monitoring. Higher sampling rates, dynamic range, and extended computational and storage capacity allow for considering of more complex methodological solutions such as high-frequency QRS analysis for diagnosing myocardial ischemia. Implementation of suitable methodologies for advanced detection of myocardial ischemia into modern ambulatory monitoring devices creates the potential of making the ambulatory myocardial ischemia monitoring a valuable diagnostic tool in clinical practice.


Assuntos
Algoritmos , Diagnóstico por Computador/métodos , Eletrocardiografia Ambulatorial/métodos , Determinação da Frequência Cardíaca/métodos , Isquemia Miocárdica/diagnóstico , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Processamento de Sinais Assistido por Computador
16.
J Electrocardiol ; 49(1): 23-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26639443

RESUMO

INTRODUCTION: The SD1 and SD2 indexes (standard deviations in two orthogonal directions of the Poincaré plot) carry similar information to the spectral density power of the high and low frequency bands but have the advantage of easier calculation and lesser stationarity dependence. METHODS: ECG signals from metabolic syndrome (MetS) and control group patients during tilt table test under controlled breathing (20 breaths/minute) were obtained. SD1, SD2, SDRR (standard deviation of RR intervals) and RMSSD (root mean square of successive differences of RR intervals) were evaluated for 31 control group and 33 MetS subjects. RESULTS: Statistically significant lower values were observed in MetS patients in supine position (SD1: p=0.03, SD2: p=0.002, SDRR: p=0.006, RMSSD: p=0.01) and during tilt (SD2: p=0.004, SDRR: p=0.007). CONCLUSION: SD1 and SD2 combining the advantages of time and frequency domain methods, distinguish successfully between MetS and control subjects.


Assuntos
Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Frequência Cardíaca , Síndrome Metabólica/diagnóstico , Síndrome Metabólica/fisiopatologia , Oscilometria/métodos , Adulto , Algoritmos , Diagnóstico por Computador , Eletrocardiografia , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
BMC Neurosci ; 16: 47, 2015 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-26205426

RESUMO

BACKGROUND: Until now there has been no way of distinguishing between physiological and epileptic hippocampal ripples in intracranial recordings. In the present study we addressed this by investigating the effect of cognitive stimulation on interictal high frequency oscillations in the ripple range (80-250 Hz) within epileptic (EH) and non-epileptic hippocampus (NH). METHODS: We analyzed depth EEG recordings in 10 patients with intractable epilepsy, in whom hippocampal activity was recorded initially during quiet wakefulness and subsequently during a simple cognitive task. Using automated detection of ripples based on amplitude of the power envelope, we analyzed ripple rate (RR) in the cognitive and resting period, within EH and NH. RESULTS: Compared to quiet wakefulness we observed a significant reduction of RR during cognitive stimulation in EH, while it remained statistically marginal in NH. Further, we investigated the direct impact of cognitive stimuli on ripples (i.e. immediately post-stimulus), which showed a transient statistically significant suppression of ripples in the first second after stimuli onset in NH only. CONCLUSION: Our results point to a differential reactivity of ripples within EH and NH to cognitive stimulation.


Assuntos
Cognição/fisiologia , Epilepsia/fisiopatologia , Hipocampo/fisiopatologia , Adulto , Eletrodos Implantados , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Reconhecimento Automatizado de Padrão , Descanso , Percepção Visual/fisiologia , Vigília , Adulto Jovem
18.
Brain Topogr ; 28(2): 269-78, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24838818

RESUMO

Cognitive adverse effects were reported after the deep brain stimulation (DBS) of the anterior nucleus of the thalamus (AN) in epilepsy. As the AN may have an influence on widespread neocortical networks, we hypothesized that the AN, in addition to its participation in memory processing, may also participate in cognitive activities linked with the frontal neocortical structures. The aim of this study was to investigate whether the AN might participate in complex motor-cognitive activities. Three pharmacoresistant epilepsy patients implanted with AN-DBS electrodes performed two tasks involving the writing of single letters: (1) copying letters from a monitor; and (2) writing of any letter other than that appearing on the monitor. The cognitive load of the second task was increased. The task-related oscillatory changes and evoked potentials were assessed. Local event-related alpha and beta desynchronization were more expressed during the second task while the lower gamma synchronization decreased. The local field event-related potentials were elicited by the two tasks without any specific differences. The AN participates in cognitive networks processing complex motor-cognitive tasks. Attention should be paid to executive functions in subjects undergoing AN-DBS.


Assuntos
Núcleos Anteriores do Tálamo/fisiopatologia , Cognição/fisiologia , Destreza Motora/fisiologia , Redação , Adulto , Ritmo alfa , Núcleos Anteriores do Tálamo/patologia , Ritmo beta , Estimulação Encefálica Profunda , Resistência a Medicamentos , Eletroencefalografia , Epilepsia/patologia , Epilepsia/fisiopatologia , Epilepsia/terapia , Potenciais Evocados , Feminino , Ritmo Gama , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tempo de Reação , Percepção Visual/fisiologia
19.
Aust Crit Care ; 28(4): 203-7, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26530412

RESUMO

OBJECTIVE: Pulse pressure variations (PPV) are mainly influenced by ventilation. The impact of sedation on PPV is not known. The aim of the study was to test the influence of sedation on pulse pressure variation in mechanically ventilated critically ill patients and to compare PPV in critically ill and brain dead patients. Beside the absolute value of PPV, the adjusted values of pulse pressure were used to eliminate influence of ventilation. DESIGN AND INTERVENTION: Mechanically ventilated patients received four different breath frequencies. At each frequency airway pressure was adjusted to keep the end-tidal CO2 stable. In critically ill patients the frequencies were applied at basal (bispectral index - BIS median 38) and deeper sedation (BIS 29). MAIN OUTCOME MEASURES: Simultaneous haemodynamic and respiratory data including oesophageal pressure were recorded, adjusted PPV were calculated as PPV/VT, PPV/dPair, PPV/dPes where VT is tidal volume, dPair and dPes are airway and oesophageal driving pressures. SETTING: University Hospital, ICU. PARTICIPANTS: 30 critically ill and 23 patients with a diagnosis of brain death. RESULTS: The pulse pressure variation did not change significantly during deep sedation compared to basal sedation (median 10.3 vs 10.9%) whereas PPV/dPair increased from 0.7 to 0.8%/cmH2O and PPV/dPes from 1.9%/cmH2O to 2.4%/cmH2O (p=0.04). Patients with a diagnosis of brain death had higher PPV and adjusted PPV than critically ill patients. CONCLUSION: Deeper sedation increases values of adjusted pulse pressure variation.


Assuntos
Pressão Sanguínea/fisiologia , Estado Terminal , Respiração Artificial , Idoso , Morte Encefálica , Feminino , Hemodinâmica/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Respiração com Pressão Positiva
20.
J Neural Transm (Vienna) ; 121(12): 1507-22, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24809684

RESUMO

An infrequent change to an otherwise repetitive sequence of stimuli leads to the generation of mismatch negativity (MMN), even in the absence of attention. This evoked negative response occurs in the scalp-recorded electroencephalogram (EEG) over the temporal and frontal cortices, 100-250 ms after onset of the deviant stimulus. The MMN is used to detect sensory information processing. The aim of our study was to investigate whether MMN can be recorded in the subthalamic nuclei (STN) as evidence of auditory information processing on an unconscious level within this structure. To our knowledge, MMN has never been recorded in the human STN. We recorded intracerebral EEG using a MMN paradigm in five patients with Parkinson's disease (PD) who were implanted with depth electrodes in the subthalamic nuclei (STN). We found far-field MMN when intracerebral contacts were connected to an extracranial reference electrode. In all five PD patients (and nine of ten intracerebral electrodes), we also found near-field MMN-like potentials when intracerebral contacts were referenced to one another, and in some electrodes, we observed phase reversals in these potentials. The mean time-to-peak latency of the intracerebral MMN-like potentials was 214 ± 38 ms (median 219 ms). We reveal MMN-like potentials in bilateral STN. This finding provides evidence that STN receives sensory (auditory) information from other structures. The question for further research is whether STN receives such signals through a previously described hyperdirect pathway between STN and frontal cortex (a known generator of the MMN potential) and if the STN contributes to sensorimotor integration.


Assuntos
Variação Contingente Negativa/fisiologia , Potenciais Evocados Auditivos/fisiologia , Doença de Parkinson/patologia , Núcleo Subtalâmico/fisiopatologia , Estimulação Acústica , Idoso , Eletroencefalografia , Feminino , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Doença de Parkinson/complicações , Tempo de Reação/fisiologia , Índice de Gravidade de Doença , Tomógrafos Computadorizados
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