Recorded Event (recorded + event)

Distribution by Scientific Domains


Selected Abstracts


Experience With Implantable Loop Recorders for Recurrent Unexplained Syncope

CONGESTIVE HEART FAILURE, Issue 2008
Michele Brignole MD
Knowledge of what occurs during spontaneous syncope is the gold standard for evaluation. Initially, implantable loop recorders (ILRs) were used in patients with unexplained syncope at the end of unsuccessful full, conventional work-up. In pooled data regarding 247 patients, a correlation between syncope and electrocardiographic findings was found in 84 patients (34%); of these, 52% had a bradycardia or asystole at the time of the recorded event, 11% had tachycardia, and 37% had no arrhythmia. Presyncope-electrocardiography correlation was observed in another third of the patients; presyncope was much less likely to be associated with an arrhythmia than was syncope. The diagnostic yield was similar in patients with and without structural heart diseases and was higher in older than in younger patients. Recent studies showed that ILR implantation can be safely performed in an early phase of the diagnostic evaluation,provided that patients at risk for life-threatening events are carefully excluded,in the patients who have a severe presentation of syncope (because of high risk of trauma or high frequency of episodes) which can be a benefit of a mechanism-specific therapy. Congest Heart Fail. 2008;14:7,12. ©2008 Le Jacq [source]


Reverse modelling for seismic event characterization

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2005
Dirk Gajewski
SUMMARY The localization of seismic events is of utmost importance in seismology and exploration. Current techniques rely on the fact that the recorded event is detectable at most of the stations of a seismic network. Weak events, not visible in the individual seismogram of the network, are missed out. We present an approach, where no picking of events in the seismograms of the recording network is required. The observed wavefield of the network is reversed in time and then considered as the boundary value for the reverse modelling. Assuming the correct velocity model, the reversely modelled wavefield focuses on the hypocentre of the seismic event. The origin time of the event is given by the time where maximum focussing is observed. The spatial extent of the focus resembles the resolution power of the recorded wavefield and the acquisition. This automatically provides the uncertainty in the localization with respect to the bandwidth of the recorded data. The method is particularly useful for the upcoming large passive networks since no picking is required. It has great potential for localizing very weak events, not detectable in the individual seismogram, since the reverse modelling sums the energy of all recorded traces and, therefore, enhances the signal-to-noise ratio similar to stacking in seismic exploration. The method is demonstrated by 2-D and 3-D numerical case studies, which show the potential of the technique. Events with a S/N ratio smaller than 1 where the events cannot be identified in the individual seismogram of the network are localized very well by the method. [source]


Demonstration of Myocardial Ischemia by an Internal Loop Recorder

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2000
STEPHEN C. VLAY
VLAY, S.C., et al.: Demonstration of Myocardial Ischemia by an Internal Loop Recorder. An internal loop recorder (ILR) implanted to evaluate syncope was activated during an episode of chest pain. Analysis of the recorded event revealed a marked increase in the amount of ST-segment depression over baseline. In addition to rhythm analysis, the ILR may be able to assess myocardial ischemia. Further refinements of filtering may make analysis more accurate. [source]


Spatiotemporal characterization of interswarm period seismicity in the focal area Nový Kostel (West Bohemia/Vogtland) by a short-term microseismic study

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2009
Martin Häge
SUMMARY The West Bohemia/Vogtland region is one of the seismically most interesting areas in Europe because of its swarm-like occurrence of seismicity. The installation of the local West Bohemian seismological network (WEBNET) has made the recording of small magnitude seismicity (detection threshold ML,,0.5) possible. We investigated if microseismicity exists below the detection threshold of WEBNET. A microseismic field campaign was carried out in the focal area Nový Kostel. The measurement was performed with three small arrays lasting for 6 d in a seismically quiet, interswarm period. We were able to detect and locate 13 microearthquakes in the magnitude range ,1.5 ,ML,,0.1 and achieved a detection threshold about one magnitude lower than the local network. A relative location suggests that the recorded seismicity is rather related to a specific fault segment than randomly distributed. The determined fault zone is aligned NW,SW and confirms the viability of mapping active faults with short-term measurements. The results demonstrate that a linear extrapolation of the b -value, determined by the network bulletin, down to ML=,0.5 fits well with the amount of our recorded events. [source]