References of "Gérard, Paul"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailEffect of a novel thromboxane A(2) inhibitor on right ventricular-arterial coupling in endotoxic shock
Lambermont, Bernard ULg; Kolh, Philippe ULg; Ghuysen, Alexandre ULg et al

in Shock (2004), 21(1), 45-51

We investigated the effects of a dual thromboxane (TX)A(2) synthase inhibitor and TXA(2) receptor antagonist (BM-573) on right ventricular-arterial coupling in a porcine model of endotoxic shock. Thirty ... [more ▼]

We investigated the effects of a dual thromboxane (TX)A(2) synthase inhibitor and TXA(2) receptor antagonist (BM-573) on right ventricular-arterial coupling in a porcine model of endotoxic shock. Thirty minutes before the onset of 0.5 mg/kg endotoxin infusion, six pigs (Endo group) received an infusion with a placebo solution, and six other pigs (Anta group) with BM-573. Right ventricular pressure-volume loops were obtained by the conductance catheter technique. The slope (E-es) of the end-systolic pressure-volume relationship and its volume intercept at 25 mmHg were calculated as measures of right ventricular systolic function. RV afterload was quantified by pulmonary arterial elastance (E-a), and E-es/E-a ratio represented right ventricular-arterial coupling. Mechanical efficiency was defined as the ratio of stroke work and pressure-volume area. In this model of endotoxic shock, BM-573 blunted the early phase of pulmonary hypertension, improved arterial oxygenation, and prevented a decrease in right ventricular myocardial efficiency and right ventricular dilatation. However, the drug could not prevent the loss of homeometric regulation and alterations in right ventricular-arterial coupling. In conclusion, dual TXA(2) synthase inhibitor and receptor antagonists such as BM-573 have potential therapeutic applications, improving right ventricular efficiency and arterial oxygenation in endotoxic shock. [less ▲]

Detailed reference viewed: 24 (2 ULg)
Full Text
Peer Reviewed
See detailComparison between single-beat and multiple-beat methods for estimation of right ventricular contractility.
Lambermont, Bernard ULg; Segers, Patrick; Ghuysen, Alexandre ULg et al

in Critical Care Medicine (2004), 32(9), 1886-90

OBJECTIVE: It was investigated whether pharmacologically induced changes in right ventricular contractility can be detected by a so-called "single-beat" method that does not require preload reduction ... [more ▼]

OBJECTIVE: It was investigated whether pharmacologically induced changes in right ventricular contractility can be detected by a so-called "single-beat" method that does not require preload reduction. DESIGN: Prospective animal research. SETTING: Laboratory at a large university medical center. SUBJECTS: Eight anesthetized pigs. INTERVENTIONS: End-systolic elastance values obtained by a recently proposed single-beat method (Eessb) were compared with those obtained using the reference multiple-beat method (Eesmb). MEASUREMENTS AND MAIN RESULTS: Administration of dobutamine increased Eesmb from 1.6 +/- 0.3 to 3.8 +/- 0.5 mm Hg/mL (p =.001), whereas there was only a trend toward an increase in Eessb from 1.5 +/- 0.2 to 1.7 +/- 0.4 mm Hg/mL. Esmolol decreased Eesmb from 1.7 +/- 0.3 to 1.1 +/- 0.2 mm Hg/mL (p =.006), whereas there was only a trend for a decrease in Eessb from 1.5 +/- 0.2 to 1.3 +/- 0.1. CONCLUSIONS: The present method using single-beat estimation to assess right ventricular contractility does not work as expected, since it failed to detect either increases or decreases in right ventricular contractility induced by pharmacologic interventions. [less ▲]

Detailed reference viewed: 41 (19 ULg)
Full Text
Peer Reviewed
See detailEffect of hemodiafiltration on pulmonary hemodynamics in endotoxic shock
Lambermont, Bernard ULg; Kolh, Philippe ULg; Ghuysen, Alexandre ULg et al

in Artificial Organs (2003), 27(12), 1128-1133

Hemofiltration can improve pulmonary hemodynamics during septic shock. The main objective of the study was to determine whether hemodiafiltration (HDF) would also have beneficial effects on pulmonary ... [more ▼]

Hemofiltration can improve pulmonary hemodynamics during septic shock. The main objective of the study was to determine whether hemodiafiltration (HDF) would also have beneficial effects on pulmonary hemodynamics during septic shock. In the Endo group, six anesthetized pigs received a 0.5 mg/kg endotoxin infusion over 30 min. In the HDF group (n = 6), HDF was started 30 min after the end of the endotoxin infusion, while in the Control group (n = 4) they received HDF but no endotoxin infusion. Pulmonary hemodynamics were analyzed in detail with a four-element windkessel model. Although in the Control group, HDF did not alter pulmonary hemodynamic parameters, in the HDF group, it was responsible for an amplification of the deleterious pulmonary vascular response to endotoxin insult. Our results show that HDF must be used cautiously in septic shock since it can precipitate right heart failure by increasing pulmonary vascular resistance. [less ▲]

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailEffects of increased afterload on left ventricular performance and mechanical efficiency are not baroreflex-mediated
Kolh, Philippe ULg; Ghuysen, Alexandre ULg; Tchana-Sato, Vincent ULg et al

in European Journal of Cardio - Thoracic Surgery (2003), 24(6), 912-919

Objective: To assess baroreflex intervention during increase in left ventricular afterload, we compared the effects of aortic banding on the intact cardiovascular system and under hexamethonium infusion ... [more ▼]

Objective: To assess baroreflex intervention during increase in left ventricular afterload, we compared the effects of aortic banding on the intact cardiovascular system and under hexamethonium infusion. Methods: Six open-chest pigs, instrumented for measurement of aortic pressure and flow, left ventricular pressure and volume, were studied under pentobarbital-sufentanil anesthesia. Vascular arterial properties were estimated with a four-element windkessel model. Left ventricular contractility was assessed by the slope of end-systolic pressure-volume relationship. Results: The effects of aortic banding on mechanical aortic properties were unaffected by autonomic nervous system inhibition. However, increase in peripheral arterial vascular resistance and in heart rate were prevented by hexamethonium. Aortic banding increased left ventricular contractility and stroke work. Left ventricular-arterial coupling remained unchanged, but mechanical efficiency was impaired. These ventricular changes were independent of baroreflex integrity. Conclusions: Our results demonstrate that an augmentation in afterload has a composite effect on left ventricular function. Left ventricular performance is increased, as demonstrated by increase in contractility and stroke work, but mechanical efficiency is decreased. These changes are observed independently of baroreflex integrity. Such mechanisms of autoregulation, independent of the autonomic nervous system, are of paramount importance in heart transplant patients. (C) 2003 Elsevier B.V. All fights reserved. [less ▲]

Detailed reference viewed: 35 (1 ULg)
Full Text
Peer Reviewed
See detailEffects of endotoxic shock on right ventricular systolic function and mechanical efficiency
Lambermont, Bernard ULg; Ghuysen, Alexandre ULg; Kolh, Philippe ULg et al

in Cardiovascular Research (2003), 59(2), 412-418

Objective: To investigate the effects of endotoxin infusion on right ventricular (RV) systolic function and mechanical efficiency. Methods: Six anesthetized pigs (Endo group) received a 0.5 mg/kg ... [more ▼]

Objective: To investigate the effects of endotoxin infusion on right ventricular (RV) systolic function and mechanical efficiency. Methods: Six anesthetized pigs (Endo group) received a 0.5 mg/kg endotoxin infusion over 30 min and were compared with six other anesthetized pigs (Control group) receiving placebo for 5 h. RV pressure-volume (PV) loops were obtained by the conductance catheter technique and pulmonary artery flow and pressure were measured with high-fidelity transducers. Results: RV adaptation to increased afterload during the early phase of endotoxin-induced pulmonary hypertension (T30) was obtained by both homeometric and hetereometric regulations: the slope of the end-systolic PV relationship of the right ventricle increased from 1.4+/-0.2 mmHg/ml to 2.9+/-0.4 mmHg/ml (P<0.05) and RV end-diastolic volume increased from 56+/-6 ml to 64+/-11 ml (P<0.05). Consequently, right ventricular-vascular coupling was maintained at a maximum efficiency. Ninety minutes later (T120), facing the same increased afterload, the right ventricle failed to maintain its contractility to such an elevated level and, as a consequence, right ventricular-vascular uncoupling occurred. PV loop area, which is known to be highly correlated with oxygen myocardial consumption, increased from 1154+/-127 mmHg/ml (T0) to 1798+/-122 mmHg/ml (T180) (P<0.05) while RV mechanical efficiency decreased from 63+/-2% (T0) to 45+/-5% (T270) (P<0.05). Conclusions: In the very early phase of endotoxinic shock, right ventricular-vascular coupling is preserved by an increase in RV contractility. Later, myocardial oxygen consumption and energetic cost of RV contractility are increased, as evidenced by the decrease in RV efficiency, and right ventricular-vascular uncoupling occurs. Therefore, therapies aiming at restoring right ventricular-vascular coupling in endotoxic shock should attempt to increase RV contractility and to decrease RV afterload but also to preserve RV mechanical efficiency. (C) 2003 European Society of Cardiology. Published by Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 13 (2 ULg)
Full Text
Peer Reviewed
See detailPredictors of early and late outcome of percutaneous coronary intervention in octogenarians
Gach, Olivier ULg; Louis, Olivier ULg; Martinez, Christophe ULg et al

in Acta Cardiologica (2003), 58(4), 289-294

Objective To evaluate the short and long-term results of percutaneous coronary interventions (PCI) in patients aged 80 years or older and to identify predictors of event-free survival. Methods and results ... [more ▼]

Objective To evaluate the short and long-term results of percutaneous coronary interventions (PCI) in patients aged 80 years or older and to identify predictors of event-free survival. Methods and results - Clinical and angiographic data from all patients undergoing percutaneous coronary intervention in our institution are prospectively collected and stored in a computerized database. The clinical and angiographic characteristics of all patients aged 80 years or older undergoing percutaneous coronary intervention between January 1994 and December 1999 were analysed retrospectively. Follow-up was obtained by interview or through the referring physician. One hundred and fifty-eight patients aged 80 years or older (median: 83.4; range: 80.2-92.2) underwent percutaneous coronary intervention in our institution during the study period. The initial angiographic success rate was 92%. In-hospital mortality was 8.2% and procedural success 84.8%. One-year and two-year survival were 81% and 72.2% respectively, while event free survival at 1 year and 2 years was 65.8% and 57%. Using the Cox proportional hazards method, we identified incomplete revascularization and low left ventricular ejection fraction (WEF) as predictors of death at 2 years. Complete revascularization and stenting were independent predictors of 2-year event-free survival. Conclusion - Percutaneous coronary intervention can be performed safely in octogenarians. Complete revascularization, stenting and preserved left ventricular ejection fraction were independent predictors of better outcome in this population. [less ▲]

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
See detailEffects of U-46619 on Pulmonary Hemodynamics before and after Administration of Bm-573, a Novel Thromboxane A2 Inhibitor
Lambermont, Bernard ULg; Kolh, Philippe ULg; Dogné, Jean-Michel ULg et al

in Archives of Physiology & Biochemistry (2003), 111(3), 217-23

We studied the effects on pulmonary hemodynamics of U-46619, a thromboxane A2 (TXA2) agonist, before and after administration of a novel TXA2 receptor antagonist and synthase inhibitor (BM-573). Six ... [more ▼]

We studied the effects on pulmonary hemodynamics of U-46619, a thromboxane A2 (TXA2) agonist, before and after administration of a novel TXA2 receptor antagonist and synthase inhibitor (BM-573). Six anesthetized pigs (Ago group) received 6 consecutive injections of U-46619 at 30-min interval and were compared with six anesthetized pigs (Anta group) which received an increasing dosage regimen of BM-573 10 min before each U-46619 injection. Consecutive changes in pulmonary hemodynamics, including characteristic resistance, vascular compliance, and peripheral vascular resistance, were continuously assessed during the experimental protocol using a four-element Windkessel model. At 2 mg/kg, BM-573 completely blocked pulmonary hypertensive effects of U-46619 but pulmonary vascular compliance still decreased. This residual effect can probably be explained by a persistent increase in the tonus of the pulmonary vascular wall smooth muscles sufficient to decrease vascular compliance but not vessel lumen diameter. Such molecule could be a promising therapeutic approach in TXA2 mediated pulmonary hypertension as it is the case in pulmonary embolism, hyperacute lung rejection and endotoxinic shock. [less ▲]

Detailed reference viewed: 23 (2 ULg)
Full Text
Peer Reviewed
See detailEffects of Bm-573, a Novel Thromboxane A2 Inhibitor, on Pulmonary Hemodynamics in Endotoxic Shock
Lambermont, Bernard ULg; Ghuysen, Alexandre ULg; Dogné, Jean-Michel ULg et al

in Archives of Physiology & Biochemistry (2003), 111(3), 224-31

Thromboxane A2 is considered to be partially responsible for the increase in pulmonary vascular resistance observed after endotoxin administration and to participate in proinflammatory reactions. The ... [more ▼]

Thromboxane A2 is considered to be partially responsible for the increase in pulmonary vascular resistance observed after endotoxin administration and to participate in proinflammatory reactions. The effects of a novel dual TXA2 synthase inhibitor and TXA2 receptor antagonist (BM-573) on pulmonary hemodynamics were investigated in endotoxic shock. 30 mins before the start of a 0.5 mg/kg endotoxin infusion, 6 pigs (Endo group) received a placebo infusion and 6 other pigs (Anta group) received a BM-573 infusion. In Endo group, pulmonary artery pressure increased from 25 +/- 1.8 (T0) to 42 +/- 2.3 mmHg (T60) (p < 0.05) after endotoxin infusion while, in Anta group, it increased from 23 +/- 1.6 (T0) to 25 +/- 1.5 mmHg (T60). This difference is due to a reduction in pulmonary vascular resistance in Anta group while pulmonary arterial compliance changes in Endo group remained comparable with the evolution in Anta group. In Endo group, PaO2 decreased from 131 +/- 21 (T0) to 74 +/- 12 mmHg (T300) (p < 0.05), while in Anta group, PaO2 was 241 +/- 31 mmHg at the end of the experimental period (T300). These results demonstrate that TXA2 plays a major role in pulmonary vascular changes during endotoxin insult. Concomitant inhibition of TXA2 synthesis and of TXA2 receptors by BM-573 inhibited the pulmonary vasopressive response during the early phase of endotoxin shock as well as the deterioration in arterial oxygenation. [less ▲]

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailAlteration of left ventriculo-arterial coupling and mechanical efficiency during acute myocardial ischemia
Kolh, Philippe ULg; Lambermont, Bernard ULg; Ghuysen, Alexandre ULg et al

in International Angiology (2003), 22(2), 148-158

AIM: Myocardial revascularisation being frequently performed during acute myocardial ischemia, in a hostile hemodynamic environment, we evaluated left ventriculo-arterial (VA) coupling, left ventricular ... [more ▼]

AIM: Myocardial revascularisation being frequently performed during acute myocardial ischemia, in a hostile hemodynamic environment, we evaluated left ventriculo-arterial (VA) coupling, left ventricular (LV) mechanical efficiency, and the mechanical properties of the systemic vasculature during acute myocardial ischemia. METHODS: In 6 pigs, vascular properties [characteristic impedance (R(1)), peripheral resistance (R(2)), compliance (C), inductance (L), arterial elastance (E(a))] were estimated with a windkessel model. LV function was assessed by the slope (E(es)) of end-systolic pressure-volume relationship (ESPVR), and stroke work (SW) - end-diastolic volume (EDV) relation. Pressure-volume area (PVA) was referred to as myocardial oxygen consumption. VA coupling was defined as E(es)/E(a), and mechanical efficiency as SW/PVA. After baseline recordings, the left anterior descending coronary artery was ligated and hemodynamic measures obtained every 30 minutes for 3 hours. Data are expressed as mean (SEM). RESULTS: Coronary occlusion induced an ESPVR rightward shift, and decreased E(es) from 3.67 (0.33) to 1.92 (0.20) mmHg/ml and the slope of the SW - EDV relationship from 72.3 (3.4) to 40.4 (4.5) mmHg (p<0.001), while E(a) increased from 3.33 (0.56) to 4.65 (0.29) mmHg/ml (p<0.005). This was responsible for a dramatic alteration of VA coupling from 1.22 (0.11) to 0.44 (0.07), (p<0.001). While R2 increased from 1.72 (0.30) to 2.38 (0.16) mmHg x s x ml(-1) (p<0.05) and C decreased from 0.78 (0.16) to 0.46 (0.08) ml/mmHg (p<0.05), R(1) and L were unchanged. Coronary occlusion decreased SW from 4056 (223) to 2580 (122) mmHg.ml (p<0.001), while PVA and SW/PVA decreased from 5575 (514) to 4813 (317) mmHg x ml (NS), and from 0.76 (0.04) to 0.57 (0.03) (p<0.001), respectively. CONCLUSION: Acute myocardial ischemia severely altered left ventriculo-arterial coupling and LV mechanical efficiency. Impaired left VA coupling was due to a combination of augmented arterial elastance, secondary to early vasoconstriction later associated with decreased arterial compliance, and decreased LV contractility. [less ▲]

Detailed reference viewed: 34 (0 ULg)
Full Text
Peer Reviewed
See detailNormal ranges for the variability in heart rate in young infants while sleeping
Massin, M. M.; Withofs, Nadia ULg; Maeyns, K. et al

in Cardiology in the Young (2001), 11(6), 619-625

Objective: Measurements of the variability in heart rate are increasingly used as markers of cardiac autonomic activity. We sought to establish the development this variability in healthy young infants ... [more ▼]

Objective: Measurements of the variability in heart rate are increasingly used as markers of cardiac autonomic activity. We sought to establish the development this variability in healthy young infants while sleeping. Patients: We carried out polygraphic studies with electrocardiographic recording in 587 healthy infants aged from 5 to 26 weeks. Methods: We determined several variables over a period of 400 minutes sleeping: mean RR interval, 5 time-domain (SDNN, SDNNi, SDANNi, RMSSD, and pNN50) and 5 frequency-domain indexes (spectral power over 3 regions of interest, total power and low-to-high frequency ratio). Frequency-domain indexes were also assessed separately for the periods of quiet sleep and those of rapid eye movement sleep. Results: Our data showed a significant correlation between the indexes of heart rate variability and the mean RR interval, the breathing rate, and the corrected age of the infants. We also demonstrated the importance of the maturation of the sleeping patterns. Conclusion: These data in a large cohort of healthy infants confirm a progressive maturation of the autonomic nervous system during sleep, and may be used to examine the influence of physiological and pathophysiological factors on autonomic control during polygraphic studies. [less ▲]

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailCardiac Surgery in Octogenarians; Peri-Operative Outcome and Long-Term Results
Kolh, Philippe ULg; Kerzmann, Arnaud ULg; Lahaye, L. et al

in European Heart Journal (2001), 22(14), 1235-43

AIMS: Because the elderly are increasingly referred for operation, we reviewed the results of cardiac surgery in patients of 80 years or older. METHODS AND RESULTS: Records of 182 consecutive ... [more ▼]

AIMS: Because the elderly are increasingly referred for operation, we reviewed the results of cardiac surgery in patients of 80 years or older. METHODS AND RESULTS: Records of 182 consecutive octogenarians who had had cardiac operations between 1992 and 1998 were reviewed. Follow-up was 100% complete. Seventy patients had coronary grafting (CABG), 70 aortic valve replacement, 30 aortic valve replacement+CABG, and 12 mitral valve repair/replacement. Rates of hospital death, stroke, and prolonged stay (>14 days) were as follows: CABG: 7 (10%), 2 (2.8%) and 41 (58%); aortic valve replacement: 6 (8.5%), 2 (2.8%) and 32 (45.7%); aortic valve replacement+CABG: 8 (26.5%), 1 (3.8%) and 14 (46.6%); mitral valve repair/replacement: 3 (25%), 1 (8.3%) and 5 (41.6%). Multivariate predictors (P<0.05) of hospital death were New York Heart Association functional class, urgent procedure, prolonged cardiopulmonary bypass time, and, after aortic valve replacement, previous percutaneous aortic valvuloplasty. Ascending aortic atheromatous disease was predictive of stroke, while pre-operative myocardial infarction was predictive of prolonged hospital stay. Actuarial 5-year survival was as follows: CABG, 65.8+/-8.8%; aortic valve replacement, 63.6+/-7.1%; aortic valve replacement+CABG, 62.4+/-6.8%; mitral valve repair/replacement, 57.1+/-5.6%; and total, 63.0+/-5.6%. Multivariate predictors of late death were pre-operative myocardial infarction, and urgent procedure. Ninety percent of long-term survivors were in New York Heart Association class I or II, and 87% believed having a heart operation after age 80 years was a good choice. CONCLUSION: Cardiac operations are successful in most octogenarians with increased hospital mortality, and longer hospital stay. Long-term survival and quality of life are good. [less ▲]

Detailed reference viewed: 21 (1 ULg)
Full Text
Peer Reviewed
See detailEarly Stage Results after Oesophageal Resection for Malignancy - Colon Interposition Vs. Gastric Pull-Up
Kolh, Philippe ULg; Honore, Pierre ULg; Degauque, C. et al

in European Journal of Cardio - Thoracic Surgery (2000), 18(3), 293-300

OBJECTIVE: The aims of our study were to determine if using the colon as a digestive transplant after oesophagectomy for cancer was associated with increased postoperative complications, and to assess the ... [more ▼]

OBJECTIVE: The aims of our study were to determine if using the colon as a digestive transplant after oesophagectomy for cancer was associated with increased postoperative complications, and to assess the impact of preoperative radiochemotherapy on postoperative hospital outcome. METHODS: From January 1990 to December 1998, 130 patients underwent oesophageal resection for malignancy. There were 103 males and 27 females (age: 61.3+/-11.5 years). Indications were squamous cell carcinoma in 69 patients and adenocarcinoma in 61. Preoperatively 30 patients (eight in stage IIB, 18 in stage III, and four in stage IV) received radiochemotherapy. There were 84 subtotal oesophagectomies, with anastomosis in the neck in 44 patients and at the thoracic inlet in 40, and 46 distal oesophageal resections. Digestive continuity was restored with the stomach in 92 patients (age: 63.4+/-10.2 years) and the colon in 38 (age: 52.3+/-12.8 years). With the exception of age (P<0.0001), there was no significant preoperative difference between gastric and colonic groups. RESULTS: Hospital mortality was 8.5% (11 patients), decreasing from 18.5% (before 1993) to 3.8% (since 1993). One patient (2.5%) died in the colonic graft group and ten (11%) in the gastric pull-up group (P=0.17). Postoperative complications occurred in 40 patients (31%), respectively, in ten (26%) and 30 (33%) patients after colonic and gastric transplants (P=0.48), and were pulmonary insufficiency or infection in 29 patients, anastomotic fistula in six, myocardial infarction in five, recurrent nerve palsy in four, renal insufficiency in three, and cerebrovascular accident in one. All fistulas occurred in the gastric pull-up group. The incidence of postoperative pulmonary complications was 70% (21/30 patients) in the subgroup who received preoperative radiochemotherapy, as compared to 11% (5/44 patients) in the subgroup of comparable staging, but without preoperative treatment (P<0.001). CONCLUSIONS: Colonic grafts are not associated with increased postoperative mortality or complications. Our results suggest that preoperative neoadjuvant treatment significantly increases postoperative pulmonary complications. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailCircadian Rhythm of Heart Rate and Heart Rate Variability
Massin, M. M.; Maeyns, K.; Withofs, Nadia ULg et al

in Archives of Disease in Childhood (2000), 83(2), 179-82

BACKGROUND: Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity. AIM: To examine circadian variation in heart rate and HRV in children. SUBJECTS: A ... [more ▼]

BACKGROUND: Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity. AIM: To examine circadian variation in heart rate and HRV in children. SUBJECTS: A total of 57 healthy infants and children, aged 2 months to 15 years, underwent ambulatory 24 hour Holter recording. Monitoring was also performed on five teenagers with diabetes mellitus and subclinical vagal neuropathy in order to identify the origin of the circadian variation in HRV. METHODS: The following variables were determined hourly: mean RR interval, four time domain (SDNN, SDNNi, rMSSD, and pNN50) and four frequency domain indices (very low, low and high frequency indices, low to high frequency ratio). A chronobiological analysis was made by cosinor method for each variable. RESULTS: A significant circadian variation in heart rate and HRV was present from late infancy or early childhood, characterised by a rise during sleep, except for the low to high frequency ratio that increased during daytime. The appearance of these circadian rhythms was associated with sleep maturation. Time of peak variability did not depend on age. Circadian variation was normal in patients with diabetes mellitus. CONCLUSION: We have identified a circadian rhythm of heart rate and HRV in infants and children. Our data confirm a progressive maturation of the autonomic nervous system and support the hypothesis that the organisation of sleep, associated with sympathetic withdrawal, is responsible for these rhythms. [less ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailIncreased Aortic Compliance Maintains Left Ventricular Performance at Lower Energetic Cost
Kolh, Philippe ULg; D'Orio, Vincenzo ULg; Lambermont, Bernard ULg et al

in European Journal of Cardio - Thoracic Surgery (2000), 17(3), 272-8

OBJECTIVE: The aim of this study was to investigate left ventricular contractility and energetic cost of cardiac ejection under conditions of acute increase in aortic compliance. METHODS: In six ... [more ▼]

OBJECTIVE: The aim of this study was to investigate left ventricular contractility and energetic cost of cardiac ejection under conditions of acute increase in aortic compliance. METHODS: In six anaesthetized pigs, ascending aortic compliance was increased by adding a volume chamber in parallel to the ascending aorta. Systemic vascular parameters, including characteristic impedance, peripheral resistance, total vascular compliance, and inertance, were estimated with a four-element windkessel model. Arterial elastance was derived from these parameters. Left ventricular systolic function was assessed by end-systolic pressure-volume relationship (end-systolic elastance), and stroke work. Pressure-volume area was used as a measure of myocardial oxygen consumption. Heart rate remained constant during the experimentation. RESULTS: Adding the aortic volume chamber significantly increased vascular compliance from 0. 95+/-0.08 to 1.17+/-0.06 ml/mmHg (P<0.01), while inductance, characteristic impedance, peripheral resistance, and arterial elastance remained statistically at basal values, respectively 0. 0020+/-0.0003 mmHg.s(2)/ml, 0.105+/-0.009 mmHg.s/ml, 1.27+/-0.12 mmHg.s/ml, and 2.43+/-0.21 mmHg/ml. During the same interval, stroke work and pressure-volume area decreased respectively from 2700+/-242 to 2256+/-75 mmHg.ml (P<0.01), and from 3806+/-427 to 3179+/-167 mmHg.ml (P<0.01). Stroke work and pressure-volume area decreased at matched end-diastolic volumes. In contrast, end-systolic elastance, ejection fraction, and stroke volume remained statistically unchanged, respectively at 2.29+/-0.14 mmHg/ml, 48.1+/-2.1 %, and 32. 4+/-1.7 ml. CONCLUSIONS: These data suggest that, when facing an increased aortic compliance, the left ventricle displays unchanged contractility, but the energetic cost of cardiac ejection is significantly decreased. These data may be of clinical importance when choosing an artificial prosthesis for ascending aortic replacement. [less ▲]

Detailed reference viewed: 19 (3 ULg)
Full Text
Peer Reviewed
See detailDependency of Premature Ventricular Contractions on Heart Rate and Circadian Rhythms During Childhood
Massin, M. M.; Maeyns, K.; Withofs, Nadia ULg et al

in Cardiology (2000), 93(1-2), 70-3

The aim of the present study was to identify and quantify the rate dependence of premature ventricular contractions (PVC) during childhood. A 24-hour Holter recording was performed in 16 consecutive ... [more ▼]

The aim of the present study was to identify and quantify the rate dependence of premature ventricular contractions (PVC) during childhood. A 24-hour Holter recording was performed in 16 consecutive children, aged 22 days to 11 years (mean age 5.6 years), with frequent (>5,000/day), isolated monomorphic PVC. Those PVC were identified and the length of the preceding sinus cycle was measured. The values were ordered into 50-ms class intervals, and the percentage of PVC for each class was calculated and then analyzed by linear regression analysis. On the basis of the significance of the p value, and the positive or negative value of the slope, we identified a tachycardia-enhanced, a bradycardia-enhanced, and an indifferent pattern. Chronobiologic analysis was made by the cosinor method. All the patients had upper and lower limits of cycle length beyond which PVC disappeared. A tachycardia-enhanced pattern was present in 7 patients and an indifferent one in 9 patients. In the latter a second-degree polynomial correlation was systematically found. Children but not infants had a significant circadian variation in the frequency of PVC with a very variable time of highest incidence. In conclusion, it is possible to identify a circadian rhythm of PVC and a spontaneous trend between their incidence and the length of the preceding cardiac cycle in children. [less ▲]

Detailed reference viewed: 23 (1 ULg)
Peer Reviewed
See detailEffects of Inhaled Nitric Oxide on Pulmonary Hemodynamics in a Porcine Model of Endotoxin Shock
Lambermont, Bernard ULg; D'Orio, Vincenzo ULg; Kolh, Philippe ULg et al

in Critical Care Medicine (1999), 27(9), 1953-7

OBJECTIVE: To evaluate the effects of inhaled nitric oxide (NO) on pulmonary circulation in a porcine endotoxin shock model. DESIGN: Prospective, randomized trial. SETTING: Laboratory at a large ... [more ▼]

OBJECTIVE: To evaluate the effects of inhaled nitric oxide (NO) on pulmonary circulation in a porcine endotoxin shock model. DESIGN: Prospective, randomized trial. SETTING: Laboratory at a large university medical center. SUBJECTS: Twelve pathogen-free pigs weighing 15 to 31 kg. INTERVENTIONS: After surgical preparation, all pigs received a 0.5 mg/kg endotoxin infusion over 30 mins. One hour after the start of endotoxin, NO inhalation (40 ppm) was initiated in six pigs, whereas the six remaining pigs served to control the progression of shock in this model. Consecutive changes in systemic and pulmonary hemodynamics, including characteristic resistance, vascular compliance, peripheral vascular resistance, and inductance, were continuously assessed during the experimental protocol using a four-element Windkessel model of the pulmonary circulation. MEASUREMENTS AND MAIN RESULTS: Endotoxin insult resulted in a biphasic pulmonary artery pressure increase from 14 +/- 2 to 32 +/- 4 mm Hg. Inhaled NO reversed the resistance to blood flow in small pulmonary arteries from 596 +/- 69 to 424 +/- 36 dyne-sec/ cm5. In contrast, the vascular capacitance of the entire pulmonary circuit, which decreased from 2.4 +/- 0.2 to 0.8 +/- 0.1 mL/mm Hg throughout endotoxin challenge, remained insensitive to NO administration. CONCLUSION: In endotoxin-induced pulmonary hypertension, inhaled NO may function as a modulator of distal pulmonary arterial tone but fails to act as a regulator of larger capacitance pulmonary vessels. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailAortic Valve Replacement in the Octogenarians: Perioperative Outcome and Clinical Follow-Up
Kolh, Philippe ULg; Lahaye, Laurent; Gérard, Paul ULg et al

in European Journal of Cardio - Thoracic Surgery (1999), 16(1), 68-73

OBJECTIVES: To determine long-term results of aortic valve replacement (AVR) in patients 80 years old or older, and assess the factors influencing perioperative outcome. METHODS: Data were reviewed on 83 ... [more ▼]

OBJECTIVES: To determine long-term results of aortic valve replacement (AVR) in patients 80 years old or older, and assess the factors influencing perioperative outcome. METHODS: Data were reviewed on 83 consecutive octogenarians, undergoing aortic valve replacement between 1992 and 1997. There were 66 women and 17 men (mean age: 82.8 years). Fifty-seven patients (69%) were in New York Heart Association (NYHA) class III-IV and six had previous myocardial infarction. Three patients had previous percutaneous aortic valvuloplasty. There were 19 urgent procedures (23%). Coronary artery bypass grafting (CABG) was performed on 21 patients (25%). Possible influence of preoperative and operative variables on early and late mortality was performed with univariate and multivariate statistical analysis, and survival was estimated with the Kaplan-Meier method. RESULTS: Operative mortality was 13% (9% for AVR, 24% for AVR-CABG). Postoperative complications were respiratory failure in 19 patients, atrial fibrillation in 19, hemodialysis in four, myocardial infarction in four and stroke in two patients. Five patients required pacemaker insertion for permanent atrioventricular block. Median hospital stay and intensive care unit stay were 19.8 +/- 12.2 days and 7.9 +/- 3.4 days, respectively. Multivariate predictors of hospital death (P < 0.05) were percutaneous aortic valvuloplasty, NYHA class IV, and urgent procedure. Mean follow-up was 26.5 months. Survival at 1, 2, and 5 years was 98.5 +/- 1.4% (63 patients at risk), 93.4 +/- 3.2% (47 patients at risk), and 78.2 +/- 6.9% (six patients at risk), respectively. Preoperative myocardial infarction and urgent procedure were independent predictors of late death. At most recent follow-up, 91% were angina free and 81% were in class I-II. CONCLUSIONS: Aortic valve replacement in octogenarians can be performed with acceptable mortality. These results stress the importance of early operation on elderly patients with aortic valve disease. Both long-term survival and functional recovery are excellent. [less ▲]

Detailed reference viewed: 44 (2 ULg)
Full Text
Peer Reviewed
See detailNonlinear analysis of cardiac rythm fluctuations using DFA method
Absil, P.-A.; Sepulchre, Rodolphe ULg; Bilge, A. et al

in Physica A: Statistical Mechanics and its Applications (1999), 272

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailAnalysis of Endotoxin Effects on the Intact Pulmonary Circulation
Lambermont, Bernard ULg; Kolh, Philippe ULg; Detry, Olivier ULg et al

in Cardiovascular Research (1999), 41(1), 275-81

OBJECTIVE: The mechanism of sustained alterations in pulmonary hemodynamics during endotoxin shock remains unclear. To gain more detailed knowledge we used the four-element windkessel model as a ... [more ▼]

OBJECTIVE: The mechanism of sustained alterations in pulmonary hemodynamics during endotoxin shock remains unclear. To gain more detailed knowledge we used the four-element windkessel model as a descriptor of the pulmonary circuit. METHODS: Consecutive changes in characteristic resistance (R1), vascular compliance (C), input resistance (R2) and inductance (L) were continuously assessed following injection of endotoxin in 6 anaesthetised pigs, and were compared with the corresponding values measured in a similar group of sham-operated animals. RESULTS: Endotoxin challenge resulted in a biphasic pulmonary artery pressure response. Blood flow decreased progressively from 2.8 +/- 0.2 l/min to 2 +/- 0.2 l/min. Ohmic pulmonary vascular resistance (PVR) increased gradually from 0.2 +/- 0.04 to 0.76 +/- 0.1 mm Hg s ml-1. The early increase in PAP (from 14 +/- 2 to 27 +/- 4 mm Hg) was mediated by changes in both R1 (from 0.04 +/- 0.01 to 0.06 +/- 0.01 mm Hg s ml-1) and R2 (from 0.16 +/- 0.04 to 0.61 +/- 0.2 mm Hg s ml-1). These responses, in turn, altered the proximal vascular compliance. A subsequent increase in PAP (from 27 +/- 2 to 32 +/- 3 mm Hg) paralleled the specific decline in distal pulmonary vasculature compliance from 0.84 +/- 0.1 to 0.65 +/- 0.1 ml/mmHg. Analysis of the time course of PVR did not allow us to distinguish between vasoconstriction and stiffening of the vascular tree as mechanisms accounting for PAP changes. CONCLUSIONS: Endotoxemia leads to pulmonary hypertension, which is a result of constriction of proximal pulmonary arteries during the early phase, whereas the late phase is characterised by a decline in distal pulmonary vasculature compliance. [less ▲]

Detailed reference viewed: 19 (3 ULg)
Peer Reviewed
See detailEffects of Peep on Systemic Venous Capacitance
Lambermont, Bernard ULg; Detry, Olivier ULg; D'Orio, Vincenzo ULg et al

in Archives of Physiology & Biochemistry (1998), 105(4), 373-8

The aim of the present study was to determine effects of positive end expiratory pressure (PEEP) application on peripheral venous capacitance and relate them to concomitant central hemodynamic ... [more ▼]

The aim of the present study was to determine effects of positive end expiratory pressure (PEEP) application on peripheral venous capacitance and relate them to concomitant central hemodynamic disturbances. The venous volume-pressure (V/P) relationships were studied in 6 intact anesthetized pigs to describe the effects of PEEP on systemic venous compliance (computed as the slope of the V/P relationship) and unstressed volume (referred to as the extrapolated volume intercept). Cardiac volumes as well as partitioning of circulating blood volume between central (ITBV) and peripheral (PBV) compartments were assessed by thermo-dye dilution techniques. During a 15 cm H2O PEEP application, venous compliance was reduced by 48%, while unstressed volume was increased by 25% and peripheral blood pooling increased from 63 to 74%. As a result, left heart and right ventricular end diastolic volumes were decreased by 8% and by 44%, respectively. It is concluded that increased venous unstressed volume and reduced compliance depicted the distension of the venous tree secondary to PEEP which acted as an impediment to venous return. As a consequence, cardiac output was reduced because of decreased preload. [less ▲]

Detailed reference viewed: 12 (1 ULg)