Publications
Below you can find a list of our published research.
Below you can find a list of our published research.
94 results
Cited 7 times since 1993 (0.2 per year) source: EuropePMC
Basic research in cardiology, Volume 88, Issue 2, 1 1 1993, Pages 167-178 Effect of coronary occlusion and reperfusion on local electrical resistivity of myocardium in dogs. Steendijk P, van Dijk AD, Mur G, van der Velde ET, Baan J
The effect of coronary occlusion and reperfusion on myocardial electrical resistivity was studied in nine anesthetized open-chest dogs. Anisotropic resistivity was measured on the anterior free wall of the left ventricle (LV) before (control) and during transient occlusion of the left anterior descending (LAD) coronary artery, and during reperfusion. To measure local resistivity longitudinal (RL) and transverse (RT) to epicardial muscle fiber direction, a sensor was developed based on the four e... Abstract
Cited 13 times since 1992 (0.4 per year) source: EuropePMC
European heart journal, Volume 13 Suppl E, 1 1 1992, Pages 28-34 Single and dual excitation of the conductance-volume catheter analysed in a spheroidal mathematical model of the canine left ventricle. Steendijk P, van der Velde ET, Baan J
The conductance method employs a multi-electrode catheter to generate an electrical field and measure intracavitary segmental conductances. Left ventricular (LV) volumes are calculated using an algorithm which assumes the electrical field to be homogeneous. This assumption may be violated leading to a non-linear relation between conductance-derived and true volumes. In addition, this relation may vary between segments. A new method is introduced which uses a more homogeneous field. Volume estima... Abstract
Cited 30 times since 1992 (1 per year) source: EuropePMC
European heart journal, Volume 13 Suppl E, 1 1 1992, Pages 2-6 Ventricular pressure-volume relations in vivo. Baan J, van der Velde ET, Steendijk P
A number of fundamental mechanical properties of cardiac muscle as well as of the total ventricle are discussed. These include: Starling's law, shortening deactivation, homeometric autoregulation, and so-called hyperactivation associated with a small amount of ejection. Whenever appropriate, muscle properties are related to those of the intact ventricle. The phenomenon of load-dependence of the end-systolic pressure-volume relationship (ESPVR) receives particular attention and is placed wit... Abstract
Cited 6 times since 1992 (0.2 per year) source: EuropePMC
European heart journal, Volume 13 Suppl E, 1 1 1992, Pages 15-21 Left ventricular segmental volume by conductance catheter and Cine-CT. van der Velde ET, van Dijk AD, Steendijk P, Diethelm L, Chagas T, Lipton MJ, Glanz SA, Baan J
The ability of the conductance catheter method to measure left ventricular segmental and total volume was evaluated by comparison with the Cine-CT technique. In the seven dogs studied, 19 conductance catheter and simultaneous Cine-CT runs were obtained. High correlation coefficients were found for total volume and segmental volumes, except in the basal segment. However, in most cases there was a significant variability in slope and intercept between animals. Both methods are promising tools for... Abstract
Cited 8 times since 1992 (0.3 per year) source: EuropePMC
European heart journal, Volume 13 Suppl E, 1 1 1992, Pages 40-46 The end-systolic pressure-volume relationship in young animals using the conductance technique. Teitel DF, Klautz RJ, Cassidy SC, Steendijk P, van der Velde ET, van Bel F, Baan J
Evaluation of ventricular performance by the end-systolic pressure-volume relationship (ESPVR) has been extensively performed in the adult heart using the conductance technique. We undertook this study to validate the conductance technique and to generate ESPVRs in the small heart. To validate the technique, we simultaneously measured left ventricular volume by the conductance catheter and biplane cineangiography in nine piglets during changes in volume and contractility. Raw conductance volumes... Abstract
Cited 11 times since 1992 (0.3 per year) source: EuropePMC
Ultrasound in medicine & biology, Volume 18, Issue 5, 1 1 1992, Pages 441-449 Cerebral blood flow velocity: the influence of myocardial contractility on the velocity waveform of brain supplying arteries. Van Bel F, Steendijk P, Teitel DF, de Winter JP, Van der Velde ET, Baan J
Indices of Doppler-derived velocity waveforms of arteries perfusing the brain are used as relative measures of neonatal brain blood flow. Using a dog model, we investigated the influence of changes in myocardial contractility, induced by dobutamine, on the blood flow velocity waveform of the vertebral artery. The following indices of the velocity waveform were investigated during control states and during 5 or 10 micrograms/kg/min dobutamine infusion: peak systolic flow velocity (PSFV), temporal... Abstract
Cited 22 times since 1991 (0.7 per year) source: EuropePMC
Journal of cardiothoracic and vascular anesthesia, Volume 5, Issue 6, 1 1 1991, Pages 539-545 Systolic and diastolic pressure-volume relationships during cardiac surgery. Schreuder JJ, Biervliet JD, van der Velde ET, ten Have K, van Dijk AD, Meyne NG, Baan J
Seven patients undergoing elective coronary artery bypass surgery were studied to assess left ventricular (LV) performance by pressure-volume loops. LV pressure was measured by micromanometry and instantaneous LV volume by a conductance catheter. Continuous pressure-volume relationships were determined during preload reduction before and after cardiopulmonary bypass (CPB). End-systolic elastance (Ees), as the slope of the end-systolic pressure-volume relationship (ESPVR), and diastolic elastance... Abstract
Cited 23 times since 1991 (0.7 per year) source: EuropePMC
Pediatric research, Volume 29, Issue 5, 1 1 1991, Pages 473-482 The end-systolic pressure-volume relationship in the newborn lamb: effects of loading and inotropic interventions. Teitel DF, Klautz R, Steendijk P, van der Velde ET, van Bel F, Baan J
Indices of global systolic performance of the newborn left ventricle exceed those of the adult, despite isolated tissue studies showing immature contractile mechanisms. To evaluate contractility in situ, we investigated the end-systolic pressure-volume relationship (ESPVR) by the conductance technique in nine newborn lambs. After percutaneous placement of catheters, we generated ESPVR by inferior vena cava occlusion, aortic occlusion, and volume infusion in two control states, during three level... Abstract
Cited 74 times since 1991 (2.2 per year) source: EuropePMC
Circulation, Volume 83, Issue 1, 1 1 1991, Pages 315-327 Nonlinearity and load sensitivity of end-systolic pressure-volume relation of canine left ventricle in vivo. van der Velde ET, Burkhoff D, Steendijk P, Karsdon J, Sagawa K, Baan J
The effects of mechanical changes in loading conditions on the left ventricular end-systolic pressure-volume relation (ESPVR) were studied in nine open-chest dogs, including three dogs studied before and after beta-adrenergic blockade. Left ventricular pressure was measured with a micromanometer, and left ventricular volume was measured with a conductance catheter. ESPVRs were obtained by increasing left atrial inflow over wide volume ranges (as much as threefold) under three different condition... Abstract
Cited 2 times since 1990 (0.1 per year) source: EuropePMC
The American journal of physiology, Volume 259, Issue 5 Pt 2, 1 1 1990, Pages H1419-26 Comparison between force-velocity and end-systolic pressure-volume characterization of intrinsic LV function. van der Linden LP, van der Velde ET, Bruschke AV, Baan J
We reanalyzed experiments in in situ hearts of 16 open-chest anesthetized dogs, in which two different loading interventions were performed, i.e., an occlusion of the descending aorta (InP) and a rapid volume infusion (InV). Previous studies had demonstrated that the end-systolic elastance (Ees) of the InP was substantially larger than the Ees of the InV suggesting either a load dependency of Ees as such, or an increase in contractility during InP. The data were reanalyzed in the light of the mu... Abstract
Cited 65 times since 1988 (1.8 per year) source: EuropePMC
Circulation research, Volume 62, Issue 6, 1 1 1988, Pages 1247-1258 Sensitivity of left ventricular end-systolic pressure-volume relation to type of loading intervention in dogs. Baan J, Van der Velde ET
The influence of different types of loading intervention on the resulting end-systolic pressure-volume relation (ESPVR) of the left ventricle in situ was investigated in anesthetized open-chest dogs. Left ventricular volume was measured by conductance catheter and pressure was measured by tip-micromanometer. Two loading interventions were applied: a pressure intervention (INp) by gradually occluding the descending aorta and a volume intervention (INv) by rapidly infusing 180 ml blood into the ve... Abstract
Cited 3 times since 1988 (0.1 per year) source: EuropePMC
The American journal of physiology, Volume 254, Issue 6 Pt 2, 1 1 1988, Pages H1113-24 Identifiability of left ventricular end-systolic pressure-volume relationships. van der Linden LP, van der Velde ET, Bruschke AV, Baan J
A widely accepted model of the left ventricle (LV) consisting of a time-varying elastance and a nonlinear internal resistance was investigated to make inferences about the identifiability of its parameters by means of simulated experiments. We aimed to retrieve maximum elastance (Emax) and dead volume (Vd) by the usual slope method or end-systolic pressure-volume relations (ESPVR) and by model-based parameter identification. The ESPVR deviated increasingly from the assigned values with increasin... Abstract
Cited 517 times since 1984 (13.1 per year) source: EuropePMC
Circulation, Volume 70, Issue 5, 1 1 1984, Pages 812-823 Continuous measurement of left ventricular volume in animals and humans by conductance catheter. Baan J, van der Velde ET, de Bruin HG, Smeenk GJ, Koops J, van Dijk AD, Temmerman D, Senden J, Buis B
An eight-electrode conductance catheter previously developed by us and used to determine stroke volume in dogs was applied in human beings and dogs to measure absolute left ventricular volume quantitatively. For calibration we developed the formula V(t) = (1/alpha)(L2/sigma b)G(t) - Vc, where V(t) is time-varying left ventricular volume, alpha is a dimensionless constant, L is the electrode separation, sigma b is the conductivity of blood obtained by a sampling cuvette, and G(t) is the measured... Abstract
Cited 162 times since 1981 (3.8 per year) source: EuropePMC
Cardiovascular research, Volume 15, Issue 6, 1 1 1981, Pages 328-334 Continuous stroke volume and cardiac output from intra-ventricular dimensions obtained with impedance catheter. Baan J, Jong TT, Kerkhof PL, Moene RJ, van Dijk AD, van der Velde ET, Koops J
To improve assessment of ventricular function during cardiac catheterisation there should be available a continuous registration of stroke volume and cardiac output in addition to ventricular pressure. To obtain the desired volumetric quantities a catheter has been developed which measures changes in intraventricular dimensions by electrical impedance. For this purpose, the catheter is equipped with eight electrodes spaced over a distance equal to the long axis of the left ventricle into which i... Abstract