Biomedical subjects
M Renard
Publications and source records attributed to M Renard.
[The effects of pressotherapy on cardiovascular hemodynamics].
Right auricular and pulmonary pressures increase during pressotherapy particularly in heart failure patients.
Dexamethasone treatment of amiodarone-induced thyrotoxicosis (AIT) with or without persistent administration of the drug.
Treatment of amiodarone-induced thyrotoxicosis (AIT) with thionamide, lithium or radioactive iodine is ineffective. This particular form of hyperthyroidism is long-lasting because of the slow elimination of amiodarone. Therefore, an alternative therapy is necessary, especially for patients who need to continue permanent administration of the drug. We report 2 cases of AIT: in one case, amiodarone was interrupted; in the other case, amiodarone was continued because of recurrent ventricular tachycardia resistant to classical antiarrhythmic drugs. Both patients were successfully treated with propylthiouracil (PTU) and dexamethasone (DXT).
Pimobendane (UD-CG 115 BS) in the treatment of severe congestive heart failure. An acute haemodynamic cross-over and double-blind study with two different doses.
1. We compared the effects of two doses (5 and 10 mg) of oral pimobendane (UD-CG 115) on haemodynamics in eight patients suffering from chronic congestive heart failure. The two doses were given according to a randomized cross-over double-blind protocol; haemodynamics and plasma levels of pimobendane and its main metabolite UD-CG 212, were determined 1, 2, 3, 5, 7, 9, 11 and 12 h after each dose. 2. Both doses significantly improved the left and right ventricular functions of these patients, with a peak action 3 h after drug intake and long duration (more than 12 h). A significant dose-effect relationship was observed only for pulmonary wedge pressure and right atrial pressure. Significant correlations were found between UD-CG 212 plasma levels and cardiac index (r = 0.54, P less than 0.05), and pulmonary wedge pressure (r = 0.74, P less than 0.001); no correlation was found between these haemodynamic variables and pimobendane plasma levels. 3. One patient developed a transient drop in blood platelets together with a cutaneous rash, while three others had a transient and mild decrease of thrombocytes. 4. In conclusion, pimobendane improved right and left ventricular functions in severe heart failure. Both doses (5 and 10 mg) were effective. The higher dose induced marked improvement of the haemodynamic variables but the difference between doses was only significant for right atrial and pulmonary wedge pressures.
Limitations on the prognostic value of predischarge data after myocardial infarction.
Clinical variables and those obtained by non-invasive techniques were studied prospectively in a series of 306 patients discharged from hospital after an acute myocardial infarction. The predictive value of the data at two and 12 months was assessed by univariate and multivariate analyses. The best correlation was found for age, hypertension, bundle branch block, early and late heart failure, x ray cardiothoracic ratio, digoxin use, the number of metabolic equivalents reached during the stress test, echocardiographic wall motion score index, left ventricular end diastolic diameter, left ventricular ejection fraction, and the presence of an aneurysm. The prognostic value of the same data at 12 months was studied in those surviving for two months. There was a noticeable decline in the relative risk of all but two of the factors (number of metabolic equivalents, ventricular arrhythmias). All of the predictive variables except the x ray cardiothoracic ratio, number of metabolic equivalents, and the presence of an aneurysm lost their discriminant power. The explanation for this is the strength of statistical relations of these variables with the outcome at two months. They continued to influence the score at 12 months even when the entire patient series was considered. In conclusion, the study shows that the predictive value of most of the predischarge variables usually taken into account in the assessment of risk in patients one year after infarction does not extend beyond the first two months.
Pimobendane (UD-CG 115 BS) in chronic congestive heart failure. Short-term and one-month effects of a new inotropic vasodilating agent.
We studied the effects of oral administration of pimobendane on hemodynamics, blood gas levels, the renin-angiotensin system, and plasma catecholamines in 11 patients who were affected by severe chronic congestive heart failure. Following the administration of 5 mg, the cardiac index increased from 2.0 +/- 0.2 to 2.5 +/- 0.2 L/min/m2 (p less than 0.01), and the pulmonary wedge pressure decreased from 28 +/- 3 to 17 +/- 4 mm Hg (p less than 0.01). The maximal changes were noted five hours after intake of the drug. In spite of a significant decrease in arterial oxygen pressure (PaO2) (from 81 +/- 4 to 67 +/- 5 mm Hg; p less than 0.05), a significant increase in the oxygen delivery index was seen (from 322 +/- 32 to 436 +/- 38 ml/min/m2; p less than 0.01). The patients who were submitted to long-term treatment (5 mg twice daily) and who were reassessed after at least one month exhibited an improved cardiac index from 1.9 +/- 0.2 to 2.5 +/- 0.1 L/min/m2 (p less than 0.01), as well as a decreased pulmonary wedge pressure from 26 +/- 2 to 14 +/- 4 mm Hg (p less than 0.01). The norepinephrine levels were significantly reduced after one month (from 1,496 +/- 185 to 678 +/- 95 pg/ml; p less than 0.01), whereas the plasma renin activity was not. One patient died suddenly during the one-month follow-up period. With the exception of one case, which was also treated with heparin, a transient cutaneous rash and a drop in the level of blood platelets were observed, pimobendane was well tolerated. This new inotropic and vasodilating drug thus seems to have promise for the treatment of chronic congestive heart failure.
Effects of enoximone in patients with cardiac failure after myocardial infarction.
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[Delays in hospitalization in acute myocardial infarction. Comparison between data recorded in Brussels and in Charleroi-La Louvière].
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Nonlinear magnetoresistance and charge-density-wave depinning at liquid-helium temperatures in NbSe3.
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Relevance of forearm samples for plasma catecholamine determinations.
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[Comparison of the effects of intravenous diltiazem and a placebo on hemodynamics and blood gases in the acute phase of myocardial infarction].
We compared the effects on hemodynamics and blood gases of an intravenous perfusion of diltiazem vs placebo, administered randomly and in a double-blind fashion, to 20 patients with acute myocardial infarction (less than 24 hours). After 130 minutes, we noted a significant reduction of the arterial blood pressure and the systemic vascular resistances; the other hemodynamic variable are not significantly modified. Diltiazem causes a slight but significant decrease of PaO2 after 130 minutes in intravenous perfusion. This effect is secondary to an increase of the arterio-alveolar gradient in O2, reflecting an increase of the pulmonary shunt. This has no clinical consequence since the oxygen transfer remains stable. In conclusion, intravenous diltiazem administered red in the acute phase of myocardial infarction is well tolerated hemodynamically and clinically. It may induce a minimal arterial hypoxemia by increasing the arterio-alveolar gradient in oxygen.
A comparison of the effects of combined or separate alpha- and beta-blockade in the treatment of hypertension in the acute stage of myocardial infarction.
We have assessed the benefit of separate or combined alpha- and beta-receptor blockade in the treatment of 33 patients suffering from acute (less than 48 hr) myocardial infarction complicated by sustained (greater than 6 hr) systolic hypertension (systolic blood pressure greater than 150 mm Hg). Eight patients have been treated with metoprolol, 7 with phentolamine and 18 with labetalol. We evaluated the effects of these drugs on hemodynamics and arterial and mixed venous blood gases. The patients were divided into two groups on the basis of the pulmonary wedge pressure. The first group had a pressure greater than 15 mm Hg. It included 9 patients treated with labetalol (1.8 mg/min for 1 hr) and 7 others with phentolamine (0.6 mg/min for 1 hr). The wedge pressure in the second group was less than 13 mm Hg. Nine patients in this group had been treated with labetalol (2.1 mg/min for 1 hr) and 8 others with metoprolol (0.2 mg/kg in 15 min). Labetalol normalized the blood pressure in both groups within 1 hr as did phentolamine. Metoprolol did not significantly reduce either the systolic or the diastolic pressures. The high wedge pressures in the first group were reduced by both labetalol and phentolamine. The cardiac index was increased following phentolamine administration while it was reduced by labetalol. In the group with low wedge pressure, labetalol and metoprolol induced a slight but significant reduction in cardiac index but the pulmonary wedge pressures were significantly increased for metoprolol only. The rate-pressure product was very significantly decreased by labetalol and metoprolol but not by phentolamine. The emergency treatment of systemic hypertension occurring in the setting of acute myocardial infarction would thus appear to be best achieved by combined alpha- and beta-blockade rather than with either pure alpha- or pure beta-blockade. Phentolamine, however, would be a good drug in the presence of a reduced cardiac index.
Modulation of murine hemopoiesis by repeated injections of a glycoprotein extract from Klebsiella pneumoniae.
RU 41740, an immunomodulating agent extracted from the cell wall of Klebsiella pneumoniae, was tested for its ability to modulate hemopoiesis in mice treated intraperitoneally for ten days. In such conditions, a moderate anemia could be observed, which was rapidly reversible after the end of treatment. This anemia may partly result from a decrease of bone marrow erythroid colony forming units (CFU-E), this being incompletely compensated by the intrasplenic erythropoiesis. Moreover, the amount of granulocytes and their progenitors, i.e. granulocyte/macrophage colony forming cells (GM-CFC), increased both in the bone marrow and spleen. It is proposed that this effect of RU 41740 on granulopoiesis, which could explain the better resistance to infections in treated animals as observed elsewhere, is partly related to an increase of colony stimulating activity (CSA).
Central inhibition of sympathetic overdrive by clonidine in acute myocardial infarction with systolic hypertension. Haemodynamic study.
Intravenous clonidine was used to treat systolic hypertension (systolic blood pressure greater than 160 mm Hg) in 15 patients with acute myocardial infarction and documented sympathetic overactivity (high plasma norepinephrine). Its effects on haemodynamics and blood gases were studied. After one hour, clonidine significantly reduced the systolic (195 +/- 7 to 137 +/- 7 mm Hg, p less than 0.01) and diastolic (81 +/- 4 to 60 +/- 3 mm Hg, p less than 0.01) blood pressures as well as the systemic vascular resistance (26 +/- 2 to 20 +/- 1 IU, p less than 0.01). The cardiac index was reduced from 2.8 +/- 0.2 to 2.4 +/- 0.2 l/min X m2, p less than 0.01. This change was related to a reduction of the heart rate (92 +/- 4 to 81 +/- 4 beats/min, p less than 0.01) as the stroke index was unchanged. Pulmonary wedge pressure (15 +/- 3 to 10 +/- 2 mm Hg, p less than 0.01) and rate pressure product (18.034 +/- 1.159 to 11.274 +/- 917 mm Hg, beats/min, p less than 0.01) were also significantly decreased. The arterial oxygen tension did not change significantly but there was a significant drop in the mixed venous oxygen saturation (63 +/- 2 to 61 +/- 2%, p less than 0.02) and oxygen transport (433 +/- 41 to 409 +/- 36, p less than 0.01). Clonidine is thus able to normalize blood pressure in acute myocardial infarction; this is accompanied by a reduction in myocardial oxygen requirements and pulmonary wedge pressure. Oxygen transport to the tissues, however, may be decreased.
[Choice of a class I intravenous anti-arrhythmic drug in severe ventricular arrhythmias].
In the choice of a Class I intravenous antiarhythmic medication for the treatment of threatening ventricular extrasystoles, one must take into account the speed of action of the product, its effects on hemodynamics and conduction as well as its efficacy. The rapidity of action implies the ability to reach, without delay, a therapeutic plasma level which will depend upon the distribution volume and the dose injected. An effective plasma level may be quickly reached following the intravenous administration of lidocain, disopyramide, lorcainide, tocainide and flecainide. All antiarhythmic medications have an unfavorable effect on hemodynamics; xylocain and ajmaline seem to depress the least the left ventricular function, followed by lorcainide. Unfavorable effects on the atrio-ventricular conduction are observed with substances of type IC; the duration of QRS may be affected as well by antiarhythmic medications IA and IC, with a lengthening of QT being mostly noted type IA medications. Comparison of the efficacy of antiarhythmic medications requires a strict methodology and the current data from the literature do not permit to assert with certainty the superiority of one antiarhythmic medication over the others.
Blood gas and hemodynamic changes induced by the treatment of pulmonary congestion with vasodilators in the acute phase of myocardial infarction.
The effects of vasodilators on hemodynamics and blood gases was assessed in 31 patients suffering from acute myocardial infarction (AMI) who had clinical signs of left ventricular failure with high pulmonary wedge pressure (PWP greater than 15 mm Hg). Molsidomine (n = 10), phentolamine (n = 12) and sulmazol (n = 9) were administered intravenously to decrease the PWP by 20%. Molsidomine significantly decreased PWP after one hour with a mild increase in cardiac index (CI) inducing a slight decrease in paO2 (64 to 59 mm Hg, P less than 0.1) with no change in p-vO2. Phentolamine and Sulmazol significantly increased the CI and decreased the PWP, with a substantial increase in the pv-O2 (28 to 32 mm Hg, P less than 0.005 and 28 to 31 mm Hg, P less than 0.001) and no significant change in the paO2 (60 to 65 mm Hg, P less than 0.1 and 68 to 69 mm Hg, NS). None of these drugs significantly changes the pulmonary vascular resistance (PVR) which would explain the lack of any significant change in paO2. The treatment of pulmonary congestion in AMI by either pure venous (molsidomine) or arteriolar and venous (phentolamine and sulmazol) vasodilators does not worsen obviously pre-existant hypoxemia.
[Hemodynamic repercussions and clinical tolerance of 6 class I anti-arrhythmia agents in acute myocardial infarction].
Clinical safety and hemodynamic repercussions were studied after administration of six class I antiarrhythmics (xylocaine, ajmaline, mexiletine, lorcainide, indecainide and tocainide) to patients presenting acute myocardial infarction without complications. The hemodynamic parameters monitored generally followed the same trends. A significant decrease of more than 10 per cent of the initial value was seen in systolic blood flow after injection of lorcainide, indecainide and tocainide. Peripheral vascular resistance increased moderately. Pulmonary capillary pressure increased by more than 40 per cent of the starting value after administration of mexiletine, indecainide and tocainide (significant increase in case of mexiletine). These changes in patients presenting infarction without complications are not of clinical importance. There were, however, two very severe cases of hemodynamic reaction after administration of mexiletine. Other signs of intolerance were seen, but they were of minor importance and administration of the drugs was not interrupted. Xylocaine and ajmaline produced the smallest depression of left ventricular functional activity in these patients.
Buoyancy of human and intraocular lenses in air and in aqueous humor.
The weights of seven human lenses in air and in aqueous humor were determined and compared to those of ten intraocular lens implants (IOLs). All IOLs tested were found to be significantly lighter than the human lenses in both air and in the aqueous humor.