scholarly journals High-Bandpass Filters in Electrocardiography: Source of Error in the Interpretation of the ST Segment

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
F. Buendía-Fuentes ◽  
M. A. Arnau-Vives ◽  
A. Arnau-Vives ◽  
Y. Jiménez-Jiménez ◽  
J. Rueda-Soriano ◽  
...  
Keyword(s):  
Real Time ◽  
Fourier Transforms ◽  
Pass Filter ◽  
Discrete Fourier Transforms ◽  
Real Time Mode ◽  
Asymptomatic Patients ◽  
St Segment ◽  
Coronary Syndromes ◽  
Clinically Significant ◽  
High Pass

Introduction. Artifactual variations in the ST segment may lead to confusion with acute coronary syndromes. Objective. To evaluate how the technical characteristics of the recording mode may distort the ST segment. Material and Method. We made a series of electrocardiograms using different filter configurations in 45 asymptomatic patients. A spectral analysis of the electrocardiograms was made by discrete Fourier transforms, and an accurate recomposition of the ECG signal was obtained from the addition of successive harmonics. Digital high-pass filters of 0.05 and 0.5 Hz were used, and the resulting shapes were compared with the originals. Results. In 42 patients (93%) clinically significant alterations in ST segment level were detected. These changes were only seen in “real time mode” with high-pass filter of 0.5 Hz. Conclusions. Interpretation of the ST segment in “real time mode” should only be carried out using high-pass filters of 0.05 Hz.

scholarly journals Depth-averaged instantaneous currents in a tidally dominated shelf sea from glider observations

2016 ◽  
Author(s):  
Lucas Merckelbach
Keyword(s):  
Real Time ◽  
North Sea ◽  
Current Data ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Real Time Mode ◽  
The North ◽  
Shelf Sea ◽  
The North Sea ◽  
Better Than

Abstract. Ocean gliders have become ubiquitous observation platforms in the ocean in recent years. They are also increasingly used in coastal environments. The coastal observatory system COSYNA has pioneered the use of gliders in the North Sea, a shallow tidally energetic shelf sea. For operational reasons, the gliders operated in the North Sea are programmed to resurface every 3–5 hours. The glider's deadreckoning algorithm yields depth averaged currents, averaged in time over each subsurface interval. Under operational conditions these averaged currents are a poor approximation of the instantaneous tidal current. In this work an algorithm is developed that estimates the instantaneous current (tidal and residual) from glider observations only. The algorithm uses a second-order Butterworth low-pass filter to estimate the residual current component, and a Kalman filter based on the linear shallow water equations for the tidal component. A comparison of data from a glider experiment with current data from an ADCP deployed nearby shows that the standard deviations for the east and north current components are better than 7 cm s−1 in near-real time mode, and improve to better than 5 cm s−1 in delayed mode, where the filters can be run forward and backward. In the near-real time mode the algorithm provides estimates of the currents that the glider is expected to encounter during its next few dives. Combined with a behavioural and dynamic model of the glider, this yields predicted trajectories, the information of which is incorporated in warning messages issued to ships by the (German) authorities. In delayed mode the algorithm produces useful estimates of the depth averaged currents, which can be used in (process-based) analyses in case no other source of measured current information is available.

scholarly journals Depth-averaged instantaneous currents in a tidally dominated shelf sea from glider observations

2016 ◽  
Vol 13 (24) ◽  
pp. 6637-6649 ◽  
Author(s):  
Lucas Merckelbach
Keyword(s):  
Real Time ◽  
North Sea ◽  
Current Data ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Real Time Mode ◽  
The North ◽  
Shelf Sea ◽  
The North Sea ◽  
Better Than

Abstract. Ocean gliders have become ubiquitous observation platforms in the ocean in recent years. They are also increasingly used in coastal environments. The coastal observatory system COSYNA has pioneered the use of gliders in the North Sea, a shallow tidally energetic shelf sea. For operational reasons, the gliders operated in the North Sea are programmed to resurface every 3–5 h. The glider's dead-reckoning algorithm yields depth-averaged currents, averaged in time over each subsurface interval. Under operational conditions these averaged currents are a poor approximation of the instantaneous tidal current. In this work an algorithm is developed that estimates the instantaneous current (tidal and residual) from glider observations only. The algorithm uses a first-order Butterworth low pass filter to estimate the residual current component, and a Kalman filter based on the linear shallow water equations for the tidal component. A comparison of data from a glider experiment with current data from an acoustic Doppler current profilers deployed nearby shows that the standard deviations for the east and north current components are better than 7 cm s−1 in near-real-time mode and improve to better than 6 cm s−1 in delayed mode, where the filters can be run forward and backward. In the near-real-time mode the algorithm provides estimates of the currents that the glider is expected to encounter during its next few dives. Combined with a behavioural and dynamic model of the glider, this yields predicted trajectories, the information of which is incorporated in warning messages issued to ships by the (German) authorities. In delayed mode the algorithm produces useful estimates of the depth-averaged currents, which can be used in (process-based) analyses in case no other source of measured current information is available.

scholarly journals Implementasi Model Mobile Augmented Reality e-Booklet untuk Mempromosikan Object Wisata Unggulan Provinsi Riau dengan metode 3D Object Tracking

2016 ◽  
Vol 1 (2) ◽  
pp. 177
Author(s):  
Unang Rio ◽  
Susi Erlinda ◽  
Dwi Haryono
Keyword(s):  
Augmented Reality ◽  
Object Tracking ◽  
Real Time ◽  
Mobile Augmented Reality ◽  
Pass Filter ◽  
3D Object ◽  
High Pass Filter ◽  
High Pass

Intisari  - Provinsi Riau terletak di lokasi yang strategis dan memiliki kekayaan keindahan alam dan budaya  yang  unik,  Riau  menawarkan  banyak  tempat  wisata  baik alam dan  budaya.  Tujuan  dari penelitian ini untuk membuat aplikasi  yang membantu masyarakat  untuk mendapatkan informasi objek wisata unggulan di Provinsi Riau. Salah satu faktor yang menyebabkan kurang berkembangnya sektor pariwisata di Provinsi Riau saat ini adalah karena pengelolaan informasi yang bersifat promosi dan belum mampu memaksimalkan ketersediaan teknologi informasi yang tersedia. Penggunaan teknologi augmented reality adalah teknologi yang menggabungkan benda maya tiga dimensi ke dalam  sebuah  lingkungan  tiga-dimensi  nyata  dan  kemudian  memproyeksikan  benda-benda  maya secara real time. Markerless objek wisata unggulan adalah bono surfing, balap alur, tongkang bahan bakar, pantai Rupat, istana siak dan Candi Muara Takus. pembuatan obyek dan membaca penanda scan dari kamera menggunakan teknik markerbase dan Markerless dengan objek Pelacakan metode 3D dan algoritma SIFT (Skala Fitur invarian Transform). Proses yang terkandung dalam deteksi obyek membaca gambar, mempertajam gambar dengan memanfaatkan High Pass Filter; membaca gambar dari metode SIFT bahwa proses akan menghasilkan deteksi titik. Hasil pengujian untuk melihat efek dari jarak antara smartphone kamera dengan spidol, jarak yang diperoleh sangat ideal untuk menampilkan objek 3D, sampai 40 cm. pengujian aplikasi ARRiauTouris mampu mendeteksi penanda dengan jarak dekat 10 cm dan jarak maksimum 67 cm, dan memperoleh waktu rata-rata untuk objek (mean) antara 0,80 detik menjadi 0,93 detik. Kata kunci: obyek wisata, augmented reality, 3D pelacakan objek, provinsi riau

Implication of real-time telemonitoring system in the diagnostics of cardiac diseases

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I Petrov ◽  
B Boichev ◽  
I Garvanski
Keyword(s):  
Real Time ◽  
Pathological Finding ◽  
Cardiac Diseases ◽  
St Segment Elevation ◽  
Remote Diagnostics ◽  
Primary Indication ◽  
Wide Complex Tachycardia ◽  
St Segment ◽  
Wide Range ◽  
Clinically Significant

Abstract Objectives We assessed the implication of a live telemonitoring system Check Point Cardio with real-time remote diagnostics in the diagnosis of a wide range of cardiac diseases- from rhythm disturbances to ischaemic heart disease. Methods and results In the period between 10.01.2017 and 10.01.2019 a total of 14172 patients were monitored. The mean monitoring period for the whole group was 7.76 (±4.5) days. The primary indication for real-time monitoring was rhythm and conduction abnormalities (66%) and ischemia detection (34%). In 2087 (14,8%) of the patient a clinically significant pathological finding was observed. A total of 603 (4,3%) patients were referred to a planned hospitalization with the most common reasons- ST segment deviation (450 pts), clinically significant bradycardia due to AV block- (21 pts); Sinus arrest/SA block (90 pts) and pacemaker malfunction in 20 patients, wide complex tachycardia was observed in 7 patients. In addition to that 42 patients were referred to an emergent hospitalization after a contact by our team. From those patients 30 were with ST segment elevation, 10 were with ST- segment depression and 2 were with sustained wide complex tachycardia. Conclusion Real-time telemonitoring accompanied with real-time remote diagnostics is a reliable method for diagnosis of wide-range cardiac diseases. The possibility of immediate diagnosis and contact with the patient, combined with GPS localization, allows a fast reaction in case of an emergent situation. Funding Acknowledgement Type of funding source: None

Real-time digital angiocardiography using a temporal high-pass filter.

Radiology ◽  
1984 ◽  
Vol 151 (2) ◽  
pp. 517-520 ◽  
Author(s):  
C W Hardin ◽  
R A Kruger ◽  
F L Anderson ◽  
B E Bray ◽  
J A Nelson
Keyword(s):  
Real Time ◽  
Pass Filter ◽  
High Pass Filter ◽  
Digital Angiocardiography ◽  
High Pass

scholarly journals Comparison of Baseline Wander Removal Techniques considering the Preservation of ST Changes in the Ischemic ECG: A Simulation Study

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Gustavo Lenis ◽  
Nicolas Pilia ◽  
Axel Loewe ◽  
Walther H. W. Schulze ◽  
Olaf Dössel
Keyword(s):  
Simulation Study ◽  
Cardiac Myocyte ◽  
Correct Diagnosis ◽  
Ground Truth ◽  
Realistic Model ◽  
Pass Filter ◽  
St Segment ◽  
Surface Ecg ◽  
Baseline Wander ◽  
High Pass

The most important ECG marker for the diagnosis of ischemia or infarction is a change in the ST segment. Baseline wander is a typical artifact that corrupts the recorded ECG and can hinder the correct diagnosis of such diseases. For the purpose of finding the best suited filter for the removal of baseline wander, the ground truth about the ST change prior to the corrupting artifact and the subsequent filtering process is needed. In order to create the desired reference, we used a large simulation study that allowed us to represent the ischemic heart at a multiscale level from the cardiac myocyte to the surface ECG. We also created a realistic model of baseline wander to evaluate five filtering techniques commonly used in literature. In the simulation study, we included a total of 5.5 million signals coming from 765 electrophysiological setups. We found that the best performing method was the wavelet-based baseline cancellation. However, for medical applications, the Butterworth high-pass filter is the better choice because it is computationally cheap and almost as accurate. Even though all methods modify the ST segment up to some extent, they were all proved to be better than leaving baseline wander unfiltered.

150. REAL-TIME DIGITAL ANGIOCARDIOGRAPHY USING A TEMPORAL HIGH-PASS FILTER

1984 ◽  
Vol 19 (5) ◽  
pp. S38 ◽  
Author(s):  
C. W. Hardin ◽  
R. A. Kruger ◽  
F. L. Anderson ◽  
B. E. Bray ◽  
J. A. Nelson
Keyword(s):  
Real Time ◽  
Pass Filter ◽  
High Pass Filter ◽  
Digital Angiocardiography ◽  
High Pass
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