Publications
Below you can find a list of our published research.
Below you can find a list of our published research.
196 results
Cited 3 times since 1998 (0.1 per year) source: EuropePMC
Pediatric research, Volume 43, Issue 3, 1 1 1998, Pages 331-337 Contribution of synchronized atrial systole to left ventricular contraction in the newborn pig heart. Klautz RJ, Baan J, Teitel DF
Synchronized atrial contraction may be much more important in the newborn, who has a faster heart rate and a less compliant ventricle, than in the adult. We therefore investigated the extent by which synchronized atrioventricular contraction contributes to cardiac output and cardiac work in a neonatal circulation, and whether this effect can be fully explained by the Starling mechanism. In neonatal piglets, left ventricular pressure and volume (conductance catheter) were measured during atrial a... Abstract
Cited 4 times since 1997 (0.2 per year) source: EuropePMC
Pflugers Archiv : European journal of physiology, Volume 435, Issue 1, 1 1 1997, Pages 130-136 The effect of sarcoplasmic reticulum blockade on the force/frequency relationship and systolic contraction patterns in the newborn pig heart. Klautz RJ, Baan J, Teitel DF
We investigated the relationship between heart rate and contractility in seven anaesthetized young piglets by measuring contractility at different atrial pacing rates. To study the origin of this relationship we repeated the measurements after blocking the sarcoplasmic reticulum calcium release channel with ryanodine. We assessed contractility using indices derived from instantaneous left ventricular pressure and volume measured by micromanometric and conductance catheters during rapid inferior... Abstract
Cited 6 times since 1997 (0.2 per year) source: EuropePMC
The Journal of thoracic and cardiovascular surgery, Volume 114, Issue 4, 1 1 1997, Pages 560-567 Acute elevation of coronary venous pressure does not affect left ventricular contractility in the normal and stressed swine heart: implications for the Fontan operation. Klautz RJ, van Rijk-Zwikker GL, Steendijk P, Wilde J, Teitel DF, Baan J
Objective: After the Fontan operation the right atrium and, thus, the coronary sinus are connected to the pulmonary arterial system, which causes the coronary venous pressure to increase. We investigated the acute effects of elevation of coronary venous pressure on baseline hemodynamics, coronary venous flow, and left ventricular contractility. Methods: In acutely instrumented pigs, during complete right heart bypass and during constant cardiac output, pressure in the right atrium, right ventric... Abstract
Cited 5 times since 1997 (0.2 per year) source: EuropePMC
Circulation, Volume 96, Issue 3, 1 1 1997, Pages 1025-1030 Hemodynamic effects of chronic prenatal ventricular pacing for the treatment of complete atrioventricular block. Liddicoat JR, Klein JR, Reddy VM, Klautz RJ, Teitel DF, Hanley FL
Background: Increasing the heart rate of the fetus with cardiac failure caused by complete AV block (CAVB) may allow delivery of a full-term, stable neonate with preserved ventricular function. Direct fetal pacing may be a feasible method to achieve this, but the effect of pacing on the structure and function of the rapidly developing fetal heart is unknown. Methods and results: CAVB was created in fetal lambs at 80% gestation by cryoablating the AV node. Epicardial ventricular pacing at 130 bpm... Abstract
Cited 1 times since 1997 (0 per year) source: EuropePMC
Pediatric research, Volume 41, Issue 1, 1 1 1997, Pages 57-64 Perinatal left ventricular performance in fetal sheep: interaction between oxygen ventilation and contractility. Berning RA, Klautz RJ, Teitel DF
Left ventricular (LV) output nearly triples at birth, in association with increases in serum catecholamines. Similar increases in catecholamines in utero, however, do not increase output. We hypothesized that catecholamines increase contractility in utero, but that output cannot increase until LV loading conditions are changed by oxygen ventilation. To address this hypothesis, we studied nine fetal sheep acutely placed in a warm water bath (40 degrees C). Conductance and manometric catheters wer... Abstract
Cited 19 times since 1995 (0.7 per year) source: EuropePMC
Journal of the American College of Cardiology, Volume 25, Issue 6, 1 1 1995, Pages 1428-1435 Interaction between afterload and contractility in the newborn heart: evidence of homeometric autoregulation in the intact circulation. Klautz RJ, Teitel DF, Steendijk P, van Bel F, Baan J
Objectives: We undertook the present study to determine whether afterload and contractility interact in the hearts of newborn lambs. We specifically investigated whether stepwise increases in afterload increase contractility. Background: Several studies in the isolated and intact adult dog heart have shown that afterload and contractility are not independent determinants of cardiac performance; rather, they interact. Afterload and contractility are unlikely to interact in the newborn heart becau... Abstract
Cited 34 times since 1994 (1.1 per year) source: EuropePMC
The Journal of thoracic and cardiovascular surgery, Volume 107, Issue 6, 1 1 1994, Pages 1416-1422 Inhibition of the fetal stress response improves cardiac output and gas exchange after fetal cardiac bypass. Fenton KN, Heinemann MK, Hickey PR, Klautz RJ, Liddicoat JR, Hanley FL
Cardiac bypass in late-gestation fetal lambs causes severe placental vasoconstriction, which leads to fetal death from hypoxemia and respiratory acidosis. This response can be blocked by the administration of indomethacin; however, a fatal metabolic acidosis then gradually develops in the fetus. Because the fetus is known to mount an intensive catecholamine response to stress, and because the fetal myocardium is particularly sensitive to increased afterload, we hypothesized that elevated afterlo... Abstract
Cited 74 times since 1994 (2.5 per year) source: EuropePMC
Pediatric research, Volume 35, Issue 3, 1 1 1994, Pages 329-333 Relationship between brain blood flow and carotid arterial flow in the sheep fetus. van Bel F, Roman C, Klautz RJ, Teitel DF, Rudolph AM
The present study investigates whether changes in total brain blood flow can be reliably estimated by changes in carotid arterial blood flow in fetal and perinatal lambs. We therefore compared carotid arterial blood flow, measured with implanted transit-time ultrasound transducers, with brain blood flow, measured by radioactive microspheres in fetal lambs during normal oxygenation and during pulmonary ventilation with oxygen, with PO2 ranging from levels normal for the healthy fetus to levels no... Abstract
Cited 17 times since 1994 (0.6 per year) source: EuropePMC
Journal of the American College of Cardiology, Volume 23, Issue 2, 1 1 1994, Pages 514-524 Nonlinearity of the left ventricular end-systolic wall stress-velocity of fiber shortening relation in young pigs: a potential pitfall in its use as a single-beat index of contractility. Banerjee A, Brook MM, Klautz RJ, Teitel DF
Objectives: We sought to evaluate in the young heart the primary assumptions on which the current use of the mean "velocity of fiber shortening corrected for heart rate" as a noninvasive index of contractility are based. Background: End-systolic wall stress-velocity of fiber shortening relation has been applied as a single-beat, load-independent index of contractility in children. This use is based on poorly validated assumptions of linearity, parallel shifts with changing contractile... Abstract
Cited 1 times since 1994 (0 per year) source: EuropePMC
European heart journal, Volume 15, Issue 1, 1 1 1994, Pages 83-88 Acute effects of balloon valvuloplasty and pacing on left ventricular performance in children with moderate pulmonary valve stenosis, analysed by systolic and diastolic pressure-volume relationships. Witsenburg M, van der Velde ET, Klautz RJ, Hess J, Baan J
Right ventricular overload of volume and/or pressure type may affect left ventricular systolic and diastolic function. This has been shown in animal studies and has been suggested in non-invasive studies in man. Altered geometry of the left ventricle, myocardial hypertrophy and changes in contractile state may be responsible for the change in function. Balloon valvuloplasty is an effective treatment for isolated valvular pulmonary stenosis in children, and results in an immediate decrease of rig... Abstract
Cited 8 times since 1993 (0.3 per year) source: EuropePMC
Pflugers Archiv : European journal of physiology, Volume 425, Issue 5-6, 1 1 1993, Pages 426-433 Cardiac sympathetic denervation does not change the load dependence of the left ventricular end-systolic pressure/volume relationship in dogs. Schipper IB, Steendijk P, Klautz RJ, van der Velde ET, Baan J
It has been shown that in the intact canine heart the left-ventricular end-systolic pressure/volume relation (ESPVR) depends on loading conditions: an increase in arterial vascular resistance causes a leftwards shift and a steeper slope of the ESPVR, suggesting an increased inotropic state. Our purpose was to investigate the possible contribution of the sympathetic nervous system to this load sensitivity of the ESPVR, using intact, but denervated, hearts with normal coronary perfusion and afterl... Abstract
Cited 18 times since 1993 (0.6 per year) source: EuropePMC
Pediatric research, Volume 34, Issue 2, 1 1 1993, Pages 178-181 The influence of indomethacin on the autoregulatory ability of the cerebral vascular bed in the newborn lamb. van Bel F, Klautz RJ, Steendijk P, Schipper IB, Teitel DF, Baan J
Prevention of hyperperfusion of the brain in the perinatal period has been thought to be an important mechanism by which indomethacin reduces the risk for severe periventricular-intraventricular hemorrhage. The present study investigated whether an indomethacin-induced enhancement of the upper limit of cerebral vascular autoregulatory ability in the neonate contributed to this reduction in cerebral blood flow. In seven anesthetized newborn lambs, we measured temporal blood flow velocity (TMFV) i... Abstract
Cited 8 times since 1993 (0.3 per year) source: EuropePMC
Pediatric research, Volume 33, Issue 3, 1 1 1993, Pages 295-301 Myocardial perfusion and performance after indomethacin administration in newborn lambs. Klautz RJ, van Bel F, Teitel DF, Steendijk P, Baan J
Indomethacin is a drug widely used to achieve pharmacologic closure of a patent ductus arteriosus in the premature infant. In several vascular beds (brain, kidney, intestine), indomethacin has been shown to cause vasoconstriction. Possible negative effects on myocardial blood flow and performance could be deleterious in premature infants with limited cardiac reserve. Before, during, and 30 and 60 min after administration of 1 mg.kg-1 of indomethacin in nine newborn lambs, we measured coronary bl... 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 9 times since 1991 (0.3 per year) source: EuropePMC
Pediatric research, Volume 30, Issue 4, 1 1 1991, Pages 375-380 Acceleration of blood flow velocity in the carotid artery and myocardial contractility in the newborn lamb. van Bel F, Schipper IB, Klautz RJ, Teitel DF, Steendijk P, Baan J
We investigated the influence of quantitative changes in myocardial contractile state, reflected by changes in the end-systolic pressure-volume relationship (its slope and volume intercept) and by changes in the slope of the relationship between change in pressure per unit time and end-diastolic volume induced by beta-adrenergic stimulation or inhibition, on the Doppler derived blood flow velocity wave form of the carotid artery, using a newborn lamb model. Acceleration time of the velocity wave... Abstract
Cited 4 times since 1989 (0.1 per year) source: EuropePMC
Pediatric cardiology, Volume 10, Issue 1, 1 1 1989, Pages 1-9 Anatomic correction for transposition of the great arteries: first follow-up (38 patients). Klautz RJ, Ottenkamp J, Quaegebeur JM, Buis-Liem TN, Rohmer J
Between April 1983 and October 1985, 38 consecutive patients with transposition of the great arteries (TGA) underwent anatomic correction. Ages ranged from 1 day to 284 weeks (mean 26.2 weeks). Simple TGA was present in 17 patients, 17 had an associated ventricular septal defect, and the remaining four had a Taussig-Bing anomaly. Hospital mortality was 2 of 38, with 1 late death. Follow-up time varied from 6 to 35 months. Postoperative cardiac catheterization was performed in 34 of the 36 early... Abstract