scholarly journals Is Vagal Response During Left Atrial Ganglionated Plexi Stimulation a Normal Phenomenon?

2019 ◽  
Vol 12 (10) ◽  
Author(s):  
Kazuki Iso ◽  
Yasuo Okumura ◽  
Ichiro Watanabe ◽  
Koichi Nagashima ◽  
Keiko Takahashi ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Pulse Duration ◽  
High Frequency ◽  
Left Atrial ◽  
Accessory Pathway ◽  
High Frequency Stimulation ◽  
Ganglionated Plexi ◽  
Multivariate Adjustment ◽  
Frequency Stimulation ◽  
The Mean

Background: Ganglionated plexi (GPs) play an important role in both the initiation and maintenance of atrial fibrillation (AF). GPs can be located by using continuous high-frequency stimulation (HFS) to elicit a vagal response, but whether the vagal response phenomenon is common to patients without AF is unknown. Methods: HFS of the left atrial GPs was performed in 42 patients (aged 58.0±10.2 years) undergoing ablation for AF and 21 patients (aged 53.2±12.8 years) undergoing ablation for a left-sided accessory pathway. The HFS (20 Hz, 25 mA, 10-ms pulse duration) was applied for 5 seconds at 3 sites within the presumed anatomic area of each of the 5 major left atrial GPs (for a total of 15 sites per patient). We defined vagal response to HFS as prolongation of the R-R interval by >50% in comparison to the mean pre-HFS R-R interval averaged over 10 beats and active-GP areas as areas in which a vagal response was elicited. Results: Overall, more active-GP areas were found in the AF group patients than in the non-AF group patients, and at all 5 major GPs, the maximum R-R interval during HFS was significantly prolonged in the AF patients. After multivariate adjustment, association was established between the total number of vagal response sites and the presence of AF. Conclusions: The significant increase in vagal responses elicited in patients with AF compared with responses in non-AF patients suggests that vagal responses to HFS reflect abnormally increased GP activity specific to AF substrates.

Localization of left atrial autonomic ganglionated plexuses using endocardial and epicardial high frequency stimulation in patients with atrial fibrillation

Heart Rhythm ◽  
2005 ◽  
Vol 2 (5) ◽  
pp. S10-S11 ◽  
Author(s):  
Hiroshi Nakagawa ◽  
Benjamin J. Scherlag ◽  
Deborah Lockwood ◽  
Randall K. Wolf ◽  
Marvin Peyton ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
High Frequency ◽  
Left Atrial ◽  
High Frequency Stimulation ◽  
Frequency Stimulation

Abstract 18957: Modulation of Ganglionated Plexi as an Addition to Pv Isolation in Persistent Atrial Fibrillation Ablation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Sabine Ernst ◽  
Richard Underwood ◽  
Sonya Babu-Narayan ◽  
Simona Ben-Haim
Keyword(s):  
Atrial Fibrillation ◽  
3D Imaging ◽  
Imaging Study ◽  
Persistent Atrial Fibrillation ◽  
High Frequency Stimulation ◽  
Af Ablation ◽  
Road Map ◽  
Ganglionated Plexi ◽  
Individual Variations ◽  
Frequency Stimulation

Introduction: Catheter ablation of ganglionated plexi (GP) as an add on to pulmonary vein (PV) isolation has been reported to significantly improve outcome of atrial fibrillation (AF) ablation. In order to facilitate localization of these GPs, a novel imaging study is proposed that investigates the uptake of iodine-123 metaiodobenzylguanidine (mIBG, an analogon for norepinephrine) on the atrial level. This information is combined with 3D surface reconstruction from contrast computed tomography (cCT) or cardiac magnetic resonance (CMR). Methods: A total of 7 patients (5 male, mean age 64.3 yrs) with AF underwent mIBG nuclear studies using a dedicated solid state cardiac camera (D-SPECT, Spectrum Dynamics). Four patient had 4 persistent AF (3 prev. abl.) with less than 1 year of sustained AF, whereas 3 patient were in longstanding persistent AF (all prev. abl). The acquired data was merged with the 3D imaging and subsequently imported into the 3D electroanatomical mapping system (CARTO, Biosense Webster). During invasive AF ablations these sites were mapped to perform high frequency stimulation (HFS) to confirm GP locations. Results: In all pts, both the mIBG and CT scans were performed without any complications. Locations of high mIBG uptake corresponded to anatomical GP sites (LA & RA) in the majority of patients, but individual variations were observed. PV isolation was added in all but 1 pt (who had previous ablation) plus CFAE ablation if necessary. Follow-up of in median of 10.4 months demonstrated SR in all persistent AF patients (1 redo for atrial reentry). In patients with longstanding persistent AF: 2 pts are in SR (both AF at 1 week and 1 pt in AT at 6 weeks), while 1 pt remained in AF. Conclusion: The combination of mIBG and 3D imaging provides a novel type of “road map” for localizing GPs during AF ablation. As an add-on to PV (re-) isolation, this strategy was found to be beneficial for patients with persistent and longstanding persistent AF. Interestingly, pts with longstanding persistent AF (and multiple previous ablations) all recurred early in F/U but showed reversal to AT and finally SR at later stages. Further studies in larger patient cohorts need to confirm these initial observations.

Processing of Periodic Whisker Deflections By Neurons in the Ventroposterior Medial and Thalamic Reticular Nuclei

2003 ◽  
Vol 90 (5) ◽  
pp. 3087-3094 ◽  
Author(s):  
Jed A. Hartings ◽  
Simona Temereanca ◽  
Daniel J. Simons
Keyword(s):  
High Frequency ◽  
Frequency Tuning ◽  
Stimulus Frequency ◽  
High Frequency Stimulation ◽  
Firing Rates ◽  
Sensory Environment ◽  
Frequency Stimulation ◽  
The Mean ◽  
Reticular Nuclei ◽  
40 Hz

Rats employ rhythmic whisker movements to sample information in their sensory environment. To study frequency tuning and filtering characteristics of thalamic circuitry, we recorded single-unit responses of ventroposterior medial (VPm) and thalamic reticular (Rt) neurons to 1- to 40-Hz sinusoidal and pulsatile whisker deflection in lightly narcotized rats. Neuronal entrainment was assessed by a measure of the relative modulation (RM) of firing at the stimulus frequency given by the first harmonic (F1) of the cycle time histogram divided by the mean firing rate (F0). VPm signaling of both sinusoidal and periodic pulsatile whisker movements improved gradually over 1–16 and was maximal at 20–40 Hz. By contrast, the RM of Rt responses increased over 1–8 Hz, but deteriorated progressively over the 12- to 40-Hz range. In Rt, response adaptation occurred at lower stimulus frequencies and to a greater extent than in VPm. Within a train of high-frequency stimuli, Rt responses progressively decremented, possibly due to the accumulation of inhibition, whereas those of VPm neurons augmented. Mean firing rates in Rt increased 42 spikes/s over 1–40 Hz, providing tonic (low RM) inhibition during high-frequency stimulation that may enhance VPm signal-to-noise ratios. Consistent with this view, VPm mean firing rates increased only 13 spikes/s over 1–40 Hz, and inter-deflection activity was suppressed to a greater extent than stimulus-evoked responses. Rt inhibition is likely to act in concert with actions of neuromodulators in optimizing thalamic temporal signaling of high-frequency whisker movements.

Abstract 19466: Preliminary Experience Using Multiplexed Imaging of the Sympathetic Autonomic Nervous System - Impact on Outcome of Catheter Ablation of Atrial Fibrillation

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Sabine Ernst ◽  
Francesca Menichetti ◽  
Rafael Baavour ◽  
Nathaniel Roth ◽  
Jamshed Bomanji ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
High Frequency ◽  
De Novo ◽  
Imaging Study ◽  
High Frequency Stimulation ◽  
High Uptake ◽  
Af Ablation ◽  
Uptake Sites ◽  
Frequency Stimulation

Introduction: Catheter ablation of ganglionated plexi (GP) as an add on to pulmonary vein (PV) isolation has been reported to significantly improve outcome of atrial fibrillation (AF) ablation. In order to facilitate localization of these GPs, a novel imaging study is proposed, assessing the uptake of iodine-123 metaiodobenzylguanidine (mIBG, an analog of norepinephrine)in combination with 3D surface reconstruction from contrast computed tomography (cCT) or cardiac magnetic resonance (CMR). Methods: A total of 8 patients (5 male, median age 58 yrs) underwent mIBG SPECT using a dedicated cardiac camera (D-SPECT, SUMO, Spectrum Dynamics). This data was merged with 3D CMR or cCT and finally imported into CARTO (Biosense Webster). Using the individual mediastinum uptake as a normalizing factor, high uptake sites in the epicardial fat pads around the left atrium (LA) were identified. Five patients had paroxysmal AF whilst 3 present in persistent (n=2) or longstanding persistent (n=1) AF. Only 3 patients were treated de-novo, with the remaining failing in median 2 previous ablation procedures. Invasively, high uptake sites were mapped using high frequency stimulation (HFS) to confirm GP locations, which were subsequently ablated. PV (re) isolation and CFAE ablation was performed as needed. Results: Both the mIBG and CT or CMR scans were performed without complications. Focal mIBG uptake sites corresponded to anatomical GP sites, but individual variations of additional GPs were observed. Using HFS stimulation, GP sites were confirmed, but exact localization was highly depending on accurate image registration. Median follow-up of 9.2 months with all PAF and persistent AF patients in SR (1 AT redo), while the long-standing AF relapsed. Conclusion: The combination of mIBG SPECT and 3D anatomical imaging (SUMO protocol) provides a novel type of “road map” for localizing GPs during AF ablation. GPs were variable in number and location and were invasively confirmed using high frequency stimulation. Addition of GP ablation to standard AF ablation strategies seems beneficial in patients with paroxysmal or persistent AF. Further studies in larger patient cohorts are needed to confirm these initial observations.

Subthalamic Stimulation and Neuronal Activity in the Substantia Nigra in Parkinson's Disease

2007 ◽  
Vol 97 (6) ◽  
pp. 4017-4022 ◽  
Author(s):  
D. Maltête ◽  
N. Jodoin ◽  
C. Karachi ◽  
J. L. Houeto ◽  
S. Navarro ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Firing Rate ◽  
Neuronal Activity ◽  
High Frequency ◽  
High Frequency Stimulation ◽  
Motor Disability ◽  
Frequency Stimulation ◽  
The Mean

High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for severe forms of Parkinson's disease (PD). To study the effects of high-frequency STN stimulation on one of the main output pathways of the basal ganglia, single-unit recordings of the neuronal activity of the substantia nigra pars reticulata (SNr) were performed before, during, and after the application of STN electrical stimulation in eight PD patients. During STN stimulation at 14 Hz, no change in either the mean firing rate or the discharge pattern of SNr neurons was observed. STN stimulation at 140 Hz decreased the mean firing rate by 64% and the mean duration of bursting mode activity of SNr neurons by 70%. The SNr residual neuronal activity during 140-Hz STN stimulation was driven by the STN stimulation. How the decrease in rate and modification of firing pattern of SNr-evoked neural activity, during high-frequency STN stimulation, contribute to the improvement of parkinsonian motor disability remains to be elucidated.

FREQUENCY ESTIMATION FOR ATRIAL FIBRILLATION FROM HUMAN STUDIES

2016 ◽  
Vol 78 (7-4) ◽  
Author(s):  
Anita Ahmad
Keyword(s):  
Atrial Fibrillation ◽  
European Union ◽  
High Frequency ◽  
Frequency Estimation ◽  
Dominant Frequency ◽  
High Frequency Stimulation ◽  
The European Union ◽  
Mortality And Morbidity ◽  
Spectral Techniques ◽  
Frequency Stimulation

Atrial Fibrillation (AF) is the most common disorder of the heart rhythms. There are about 2.3 million people in United States and 4.5 million people in the European Union with AF [1]. It is also one of the factors that may contribute to mortality and morbidity. Researchers who apply spectral techniques show that certain areas of the atria can have higher activation frequencies than other areas. Frequency analysis is used to measure changes in Dominant Frequency (DF). We access the electrical propagation inside the atria by spectrogram plotting and examining the effect of high frequency stimulation on human.

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