Biomedical subjects

F van den Heuvel

Publications and source records attributed to F van den Heuvel.

8 recordsLinked to original sources

PubMed1996

Echocardiographic and radionuclide pulmonary blood flow patterns after transcatheter closure of patent ductus arteriosus.

BACKGROUND: Transcatheter occlusion of patent ductus arteriosus (PDA) has been associated with protrusion of the occluder device into the left pulmonary artery (LPA). This study was conducted to evaluate the significance of occluder protrusion and its implications for potential obstruction of the LPA and associated decrease of left lung perfusion. METHODS AND RESULTS: Fifty-two patients underwent successful transcatheter PDA occlusion over a period of 5 years. In this study, 49 were reexamined between March and June 1995. In addition to clinical and echocardiographic examination, lung scintigraphy was performed. Protrusion into the LPA was present in 5 of 49 patients (10%). In these patients, maximal flow velocity in the LPA was significantly (P < .01) increased. Decreased left lung perfusion, defined as < 40% of total pulmonary blood flow, was found in 7 of 49 patients (14%). Although mean left pulmonary perfusion was significantly (P = .02) decreased in patients with protrusion, there was considerable overlap with patients without protrusion, and only a weak correlation was found (r = -.35, P = .01) between flow-velocity and left lung perfusion. CONCLUSIONS: Our results demonstrate that protrusion of the device in the LPA is an infrequent finding. If present, it is associated with increased maximal flow velocity in the LPA and diminished left lung perfusion. However, echocardiography and lung scintigraphy are weakly correlated: Increased maximal blood flow velocities in the proximal LPA proved to be a poor indicator or impaired left lung perfusion. Also, decreased perfusion occurs in the absence of echocardiographic evidence of device protrusion.

Blood Flow Velocity↗

PubMed1995

Morphological, haemodynamic, and clinical variables as predictors for management of isolated ventricular septal defect.

OBJECTIVE: To assess the predictive impact of morphological, haemodynamic, and clinical variables in the management of patients with isolated ventricular septal defect. DESIGN: Retrospective analysis of variables by a sophisticated database management system. PATIENTS AND METHODS: 263 consecutive patients with isolated ventricular septal defect diagnosed by echocardiography. The morphological type and haemodynamic character of the ventricular septal defect was characterised in each patient. In addition, variables were introduced to represent the need for diuretics, growth, and potential delay in growth. In 43 patients (16.3%) the ventricular septal defect was closed surgically; 220 patients (83.7%) were managed conservatively and spontaneous closure of the ventricular septal defect occurred in 65 (29.5%). There were no deaths. RESULTS: All patients managed surgically had non-restrictive defects and were operated on during the first year of life. A few patients with non-restrictive defects were managed conservatively. The two groups differed significantly only with respect to mean growth delay (0.65 (0.27) v 0.9 (0.21), P < 0.001). Only the morphology of the ventricular septal defect significantly (P < 0.001) influenced the probability of closure. CONCLUSIONS: Findings imply that early surgical closure of ventricular septal defect is indicated in patients with non-restrictive ventricular septal defect and severe growth delay. Other patients should be managed conservatively. In these patients the morphological type of the defect determines the probability of spontaneous closure and provides an estimate of the period over which decreased in size or closure can be expected.

Child, Preschool↗

PubMed1995

SmaCS: smart classification system for the design, maintenance and use of complex terminologies. Application in pediatric cardiology.

The development of a generic Smart Classification System (SmaCS) for the design, construction, maintenance, and use of complex controlled terminologies is described. The ability of SmaCS to create and maintain terminologies that are combinations of structured terms and domain-specific knowledge is an important aspect of its design. SmaCS can therefore be used both for both controlled data-collection, using integrity rules included in the terminology, and intelligent data-retrieval. The design and implementation of SmaCS and application in the domain of pediatric cardiology are described.

Cardiology↗

PubMed1995

Smart Classification System (SmaCS): design, implementation, and application for congenital heart disease terminology.

The development of a generic Smart Classification System (SmaCS) for the design, construction, maintenance, and use of complex controlled terminologies is described. SmaCS is used to create a knowledge-base containing more than 2,500 items for the description of abnormalities, treatments, complications, etc. within the domain of congenital heart disease. The purpose of the combination of domain specific knowledge and terminology is to provide a tool useful for both data entry and the subsequent analysis of the data collected.

Artificial Intelligence↗

PubMed1994

HERMES: a health care workstation integration architecture.

An architecture is described that facilitates integration of existing databases and applications without modifying them. By means of this architecture, data from different sources dispersed in a network can be combined and directly used in existing applications or applications that have been developed specially for integration. This feature of combining data from different sources into one workstation is viewed as the enabling technology on which computer-based patient records can be built. The abstraction of computer-, network- and application-specific details is completely dealt with by the integration architecture. This integration architecture has been developed with extendibility and flexibility in mind, and allows for a growth-path towards application of the open system paradigm in medicine.

Computer Communication Networks↗

PubMed1993

A prototype integrated medical workstation environment.

In this paper the requirements, design, and implementation of a prototype integrated medical workstation environment are outlined. The aim of the workstation is to provide user-friendly, task-oriented support for clinicians, based on existing software and data. The prototype project has been started to investigate the technical possibilities of graphical user-interfaces, network technology, client-server approaches, and software encapsulation. Experience with the prototype encouraged discussion on both the limitations and the essential features for an integrated medical workstation.

Computer Graphics↗

PubMed1991

A framework for uniform access to data, software and knowledge.

An object-oriented framework is presented that offers integration of various types of entities at one workstation. Five types of entities are distinguished: data, knowledge, functions, presentation forms and hardware, and for each of these entities an 'accessor' is introduced. An accessor offers abstraction from the particularities of access to the entities. For the interaction with this framework a programming language has been defined. A restricted form of the framework has been used to implement a prototype medical workstation for the support of clinical data analysis.

Artificial Intelligence↗

PubMed1991

Integration of an object knowledge base into a medical workstation.

A simple, yet powerful, knowledge base and its development environment is described that can act as a "knowledge server", integrated into a medical workstation. In many areas, such an integration of a knowledge base with other modules and systems is required, but difficult or impossible to achieve with existing commercial development shells. Three applications of the knowledge base are described: a controlled vocabulary for the classification of Congenital Heart Diseases, an extended data model for cardiology, and management of syntax descriptions for the BMDP command language.

Artificial Intelligence↗