# [1989] Proceedings. Computers in Cardiology

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Displaying Results 1 - 25 of 121
• ### Transesophageal echo computer tomography: a new method for dynamic 3-D imaging of the heart (echo-CT)

Publication Year: 1989
| |PDF (69 KB)

Summary form only given. A device for the acquisition of standardized parallel echocardiographic imaging planes covering the entire heart and the large vessels has been developed. It consists of a conventional transesophageal probe with an additional fully flexible distal portion, which serves as housing for a freely moving ultrasonic transducer. The transducer is pulled back from the most distal ... View full abstract»

• ### Transdermal scopolamine increases heart rate variability by selective parasympathetic stimulation

Publication Year: 1989
| |PDF (82 KB)

Summary form only given. It was hypothesized that the transdermal application of low-dose scopolamine using the unique therapeutic system Transderm Scop would selectively augment parasympathetic cardiac reflex activity and increase heart rate variability. The authors tested several indices of heart rate variability in 31 healthy adults (age: 31+or-7 years) after 234 hours of exposure to one patch ... View full abstract»

• ### Analysis of 24 hour heart rate variability in post-infarction patients

Publication Year: 1989
| |PDF (58 KB)

Summary form only given. The 24-h heart rate variability (HRV) in 40 Holter tapes from the Multicenter Post-Infarction Research Group Study was examined. The first 20 Holters were part of a preliminary study which analyzed various time- and frequency-domain measures of HRV. The time-domain measures were based on the RR intervals and included the 24-h standard deviations of RR/sub n/ and RR/sub n-1... View full abstract»

• ### Spectrum of heart rate variability

Publication Year: 1989
Cited by:  Papers (1)
| |PDF (49 KB)

Summary form only given. To test the hypothesis that patients with advanced structural disease and congestive failure have intermediate heart rate variability (HRV) values, the authors compared HRV in 33 young healthy subjects without evidence of heart disease, 23 patients with ischemic heart disease complicated by stable NYHA class II-III heart failure (CHF), and 13 patients who died during Holte... View full abstract»

• ### Two stable resting potentials in a mathematical model of a non-pacemaker cardiac cell

Publication Year: 1989
| |PDF (58 KB)

Summary form only given. The equilibrium solutions of a nonpacemaker cell were followed when the intensity (I) of an added steady depolarizing bias current was varied. The nonpacemaker cell was mathematically described with the two-state-variables model of Van Capelle and Durrer. Experimental confirmation of hysteresis phenomena of the type first predicted when using this model demonstrated that i... View full abstract»

• ### Arrangement of time-sequenced-adaptive-filters for a complete fetal ECG morphology recording

Publication Year: 1989
Cited by:  Papers (2)
| |PDF (46 KB)

Summary form only given. An arrangement of several time-sequenced adaptive filters (TSAFs) has been developed where all are synchronized to the QRS complex by the use of DUS (Doppler echo-ultrasound) echocardiography. The TSAFs are configured in the noise-canceling multireferences TSAF mode and in the signal-enhancement TSAF mode. Five-lead abdominal and chest recordings are required to feed the s... View full abstract»

• ### A comprehensive noninvasive haemodynamic assessment with a single injection of technetium-99M

Publication Year: 1989
| |PDF (60 KB)

Summary form only given. In order to identify patients at high risk of subsequent cardiac events after myocardial infarction, 105 patients underwent gated blood pool ventriculography under standard conditions. An automatic program was developed using a mnemonic language and subroutines of a powerful software (F1). Nine-point smoothing and time correction were applied to the raw data and the frames... View full abstract»

• ### Inaccurate assessment of Doppler-derived mean pressure gradients by commercially available computer programs

Publication Year: 1989
| |PDF (50 KB)

Summary form only given. Computer programs incorporated with Doppler echocardiographic machines and other available programs for offline analysis provide estimation of mean pressure gradients. The accuracy of three programs in the assessment of mean gradients was evaluated. A linear relationship was found between program-derived mean pressure gradients and false gradient calculated as 4*(mean velo... View full abstract»

• ### Volumetric quantitation of leaflet geometry in mitral valve prolapse using three dimensional echocardiography

Publication Year: 1989
Cited by:  Papers (1)
| |PDF (59 KB)

Summary form only given. A technique to reconstruct topographic mitral leaflet surfaces and measure their 3-D volumetric displacement above the annulus has been developed. It allows quantitative assessment of leaflet position and displacement in both normals and patients with MVP (mitral valve prolapse) and can be used to clarify the significance of proposed clinical and echocardiographic markers ... View full abstract»

• ### Quality control in a Holter laboratory

Publication Year: 1989
| |PDF (53 KB)

Summary form only given. The quality control program in the Holter laboratory has been on going for three years. Over this time, volume has increased from 5794 ECG (electrocardiographic) tapes/year (1987) to 6038 (1988) and 6400 (projected 1989). Technician productivity has increased from 4.8 tapes/day (1987) to 5.1 (1988) and 5.7 (1989). Because of the complex process necessary to produce a full ... View full abstract»

• ### Proceedings. Computers in Cardiology (Cat. No.89CH2932-2)

Publication Year: 1989
| |PDF (339 KB)
• ### Workstation for 2-D echocardiography image processing

Publication Year: 1989, Page(s):447 - 450
Cited by:  Patents (1)
| |PDF (536 KB)

A PC-based system for echocardiographic image digital processing oriented toward the estimation of features such as contours, volumes, and wall motion is presented. The system provides real-time frame grabbing, image processing, and picture archiving. Images are real time digitized by a Matrox PIP-1024 board (512×512 pixels, 8 b/pixel, 4-frame memory). Frame grabbing is ECG (electrocardiogra... View full abstract»

• ### Shape description as a key to ECG analysis

Publication Year: 1989, Page(s):443 - 446
Cited by:  Papers (3)
| |PDF (248 KB)

The authors present an approach to the automatic analysis of electrocardiograms (ECGs) based on the criteria used by a practising cardiologist in the visual interpretation of ECGs. Practising cardiologists primarily exploit shape to focus their attention on the ECG features to be studied in detail. Shape is also an important feature in the description, recognition, and classification of patterns. ... View full abstract»

• ### HES EKG expert-an expert system for comprehensive ECG analysis and teaching

Publication Year: 1989, Page(s):77 - 80
Cited by:  Papers (1)
| |PDF (292 KB)

An expert system for comprehensive electrocardiographic diagnosis has been developed. The system provides ECG (electrocardiogram) processing by the HES ECG program, a database with validated ECGs and their accompanying clinical findings, and a knowledge base containing established rule sets for ECG classification (Cardiac Infarction Injury Score, Romhilt Estes Hypertrophy score, the Selvester scor... View full abstract»

• ### A work-station to study blood pressure ambulatory profiles

Publication Year: 1989, Page(s):439 - 442
Cited by:  Papers (1)
| |PDF (228 KB)

To facilitate and automate the analysis of blood pressure (BP) profiles from relatively dense ambulatory BP recordings, a BP work station, which is supported by a PC-compatible system to which many ambulatory monitors can be serially interfaced, has been developed. The BP time series manipulation procedure is a menu-driven collection of software packages which produce graphs in the time and phase ... View full abstract»

• ### A relaxation algorithm for segmentation of the endocardial surface from cine CT

Publication Year: 1989, Page(s):95 - 98
Cited by:  Patents (3)
| |PDF (320 KB)

A relaxation algorithm has been developed for automated segmentation of the endocardial surface from contrast cine-CT (computer tomography) images. The image is contoured at an initial density threshold, and a one-dimensional edge operator is applied orthogonally to each point of the contour. Output from the operator is used to generate a histogram, the mode of which identifies a new threshold. Th... View full abstract»

• ### DECGAP: an automatic ECG analysis program

Publication Year: 1989, Page(s):73 - 76
Cited by:  Papers (1)
| |PDF (208 KB)

A description is given of DECGAP (Democritos ElectroCardioGram Analysis Program), a program for the automatic ECG (electrocardiographic) analysis developed at the NRCPS Democritos'. The methods and algorithms used by DECGAP in the stages of preprocessing, detection-recognition, and parameter extraction of the ECG waves are described. Experimental and evaluation results are also given, with an act... View full abstract»

• ### Quantitative angiographic identification of functional left ventricular aneurysms

Publication Year: 1989, Page(s):467 - 470
Cited by:  Papers (1)  |  Patents (1)
| |PDF (244 KB)

Thirty-three 30° RAO left-ventricular angiograms with postinfarction aneurysms were analyzed to determine whether some quantitative variables could describe their morphological characteristics. Seventeen aneurysms were classified as functional (localized without a clear neck), and 16 as true (with a saccular shape). Left-ventricular volumes and global ejection fractions did not differ between ... View full abstract»

• ### Transfer function analysis of cardiovascular regulation in an open-loop animal model

Publication Year: 1989, Page(s):331 - 334
Cited by:  Papers (1)
| |PDF (344 KB)

Cardiovascular regulation involves feedback and feedforward limbs of a control loop. In order to understand the behavior of this control system, it is desirable, although difficult to disentangle the dynamical properties of the feedback and feedforward limbs. The authors have developed a conscious animal model in which the control loop is functionally opened by interruption of atrioventricular con... View full abstract»

• ### Corrections of errors in densitometry under simulated in vivo conditions

Publication Year: 1989, Page(s):437 - 438
Cited by:  Papers (1)
| |PDF (152 KB)

Errors in densitometry due to distortion, scattering, and beam hardening have been eliminated under simulated in vivo conditions. The method was tested by means of an anthropomorphic phantom. The results reveal good agreement between the evaluated relative lumina and the real vessel relations. There is a linear relationship between the integrated profile of gray values and the real cross section. ... View full abstract»

• ### Right ventricular pressure-volume loop in man by densitometric analysis of digital subtraction ventriculograms

Publication Year: 1989, Page(s):311 - 314
| |PDF (240 KB)

Densitometric analysis of digital subtraction right ventriculograms was used to assess volume changes of the right ventricle during the entire cardiac cycle with high spatial and temporal resolution and without any geometric assumption. It was also used to measure several parameters of systolic and diastolic right ventricular function. Among these parameters, peak filling rate and ejection fractio... View full abstract»

• ### Quantitative shape analysis of left ventricular cine-CT images

Publication Year: 1989, Page(s):91 - 93
| |PDF (244 KB)

The shape of the endocardial and epicardial borders of excised dog hearts digitized and traced from cine-CT (computer tomography) images have been quantitatively compared with those obtained from actual dissected cross sections digitized and traced with a video camera. Results from a standard Fourier analysis have been compared with those obtained from the proposed boundary matching descriptor met... View full abstract»

• ### An on-line system for the quantitative analysis of coronary arterial segments

Publication Year: 1989, Page(s):157 - 160
Cited by:  Papers (14)
| |PDF (448 KB)

The online quantification of coronary arteries is important for the objective and accurate assessment of the effects of coronary intervention procedures. The basic principles of a quantitative coronary arteriography (QCA) software package, to be implemented on the Philips DCI system, is described. First, a centerline of the selected arterial segment is defined. After the beginning and endpoints ar... View full abstract»

• ### Standards for electrocardiographic instrumentation

Publication Year: 1989, Page(s):69 - 71
| |PDF (184 KB)

Attention is given to the 1989 American Heart Association report, which focuses on the areas of digital processing and bandwidth requirements for automated ECG (electrocardiographic) analysis. Recommendations are developed for low- and high-frequency performance, sampling and quantization, and data compression. Fidelity criteria are described in relation to the intended applications, including rou... View full abstract»

• ### A study to match duration criteria and computer ECG measurements

Publication Year: 1989, Page(s):487 - 490
| |PDF (360 KB)

The differences between computer and conventional' manual ECG (electrocardiography) duration measurements are assessed. The ultimate goal is to adapt duration criteria designed for the visual interpretation of ECGs to analysis by computerized systems. Independently of any diagnostic indication, a set of 100 ECG signals has been used to measure several duration parameters of potential diagnostic s... View full abstract»