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Biomedical subjects

L Drieu

Publications and source records attributed to L Drieu.

8 recordsLinked to original sources
PubMed1995

[Double responses].

Double response is a rare electrocardiographic phenomenon requiring two atrioventricular conduction pathways with very different electrophysiological properties. Double ventricular responses are the usual manifestation: an atrial depolarisation (spontaneous or provoked, anticipated or not) is followed by a first ventricular response dependent on an accessory pathway or a rapid nodal pathway and then a second response resulting from sufficiently delayed transmission through a nodal pathway for the ventricles to have recovered their excitability when the second wave of activation reaches them. A simple curiosity when isolated and occurring under unusual conditions, particularly during electrophysiological investigation of the Wolff-Parkinson-White syndrome, the double response may initiate symptomatic non-reentrant junctional tachycardia when associated with nodal duality and repeating from atria in sinus rhythm. The functional incapacity and resistance to antiarrhythmic therapy may require referral for ablation of the slow pathway.

Atrioventricular Node↗
PubMed1990

[Treatment of arrhythmias in chronic cardiac insufficiency].

Arrhythmias are frequent and associated with a poor prognosis, especially when they arise from the ventricle. Although the correction of predisposing factors and improvement of hemodynamic conditions are essential, the use of antiarrhythmic drugs in this context poses problems. The treatment of even complex ventricular extrasystoles has not been shown to effectively prevent the serious arrhythmias responsible for sudden death. Depression of left ventricular function and: Or proarrhythmic effects of antiarrhythmic therapy in some patients, probably offset the benefits observed in others. The treatment of atrial arrhythmias remains traditional: reduction by drugs or electrotherapy and prevention of recurrences, or simply slowing the ventricular response. Sustained ventricular tachycardia and resuscitated ventricular fibrillation should be managed more aggressively, not by empirical antiarrhythmic treatment but by medical therapy guided by the results of electrophysiological studies, and, when this fails, by non-medical treatment: fulguration, implantable defibrillator, antiarrhythmic surgery, or even cardiac transplantation.

Adrenergic beta-Antagonists↗
PubMed1987

Renal response to volume expansion in heart-transplant and kidney-transplant recipients.

The renal excretion of an intravenous sodium load by ten heart-transplant recipients with (five patients) or without (five patients) moderate renal failure was compared with the results obtained in two matched control groups of ten kidney-transplant recipients with similar renal function. All patients were treated with prednisone and cyclosporine except, for the latter treatment, the kidney-transplant recipients without renal failure. A supplementary control group of five healthy subjects who did not receive any treatment was also included in the study. Fractional sodium and osmolal clearances were greater in heart-transplant than in kidney-transplant recipients for both the patients with and the patients without renal failure. These two parameters were also greater in heart-transplant recipients without renal failure than in healthy subjects. Free water clearance was smaller in the heart-transplant recipients than in the corresponding control patients. Fractional potassium clearance was not different from group to group. These results demonstrate that heart-transplant recipients excrete a greater fraction of the filtered sodium load than their controls. This increased fractional excretion of sodium cannot be attributed to the cyclosporine treatment or the moderate chronic renal failure which both have been taken into account in the comparisons. The unchanged blood pressure during the saline load and the high or normal plasma renin activity levels in the heart-transplant recipients make it also unlikely that the exaggerated natriuresis was the consequence of the higher blood pressure observed in these patients. The chronic cardiac denervation which is the consequence of surgery in these patients could play a role in the mechanism of the saline diuresis.

Adult↗
PubMed1986

Vasopressin, aldosterone and renin responses to volume depletion in heart-transplant recipients.

Plasma arginine vasopressin (AVP), renin activity (PRA) and aldosterone (ALD) were measured immediately before and 60 min after intravenous administration of frusemide and passage from lying to standing in 10 untreated healthy subjects (group 1), eight asthmatic patients treated with prednisone (group 2) and 13 heart-transplant recipients treated with prednisone and cyclosporin (group 3). Three different tests for cardiac vagal innervation were performed in the study population. They confirmed that the patients of group 3 were denervated whereas those of groups 1 and 2 had an intact cardiac innervation. Plasma volume depletion after frusemide administration estimated from the rise in plasma proteins was 10-12%. Mean blood pressure was higher in the transplant recipients but did not change in the three groups. Heart rate was also greater in the transplant recipients as a result of vagal denervation. PRA and ALD increased in all the subjects: 2.8, 3.3 and 2.2 times basal value for PRA, 2.7, 4.6 and 2.1 times basal value for ALD in groups 1, 2 and 3 respectively. In contrast, plasma AVP increased only in the two control groups (x1.45 and x1.65 in groups 1 and 2 respectively) whereas it was unchanged in the group of heart-transplant recipients (x1.05). In order to better understand the etiology of the high basal AVP plasma levels observed in group 3, AVP response to a standard water load was studied in eight supplementary heart-transplant recipients: 81.5% of the water load was excreted over 3 h and plasma AVP fell significantly (x0.76).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Intravenous theophylline: adaptation of dosage to blood theophylline levels at admission and to clearance].

Intravenous infusions of aminophylline expose the patient to the risk of overdosage related to the narrow safety margin of the therapeutic concentrations and to the great individual variability of its excretion. The aim of this study was to evaluate a simplified protocol designed to determine the optimal dose of theophylline based on total body clearance. Forty-four patients (average age: 63 years) admitted with decompensation of chronic respiratory failure (N = 33) or with status asthmaticus (N = 11) were studied. Theophylline was administered initially at a constant rate R0 (mg/kg/h) depending on serum theophylline concentrations on admission T0 (mg/l): R0 = 0.75 - 0.75 T0/20. Serum theophylline concentrations were measured at the 6th and 12th hours (T6 and T12) for calculation of clearance (Chiou et al. J. Pharmacokinet. Biopharm., 1978, 6, 135-151) and for adjusting dosage R. After 48 hours of treatment at this infusion rate, serum theophylline was again measured (T48) to check the adjustment of the dosage and recalculate clearance. In 11 patients T0 was greater than 15 mg/l (max = 44) and T12 was 10.5 +/- 6.4 mg/l. Theophylline was withdrawn in 6 patients with initial clearances less than 5 ml/kg/h (zero in 5 cases). T48 was within therapeutic values (10-20 mg/l) in 55 p. 100 of cases (21/38). Twelve patients had T48 less than 10 mg/l due to an increase in theophylline clearance (+ 80 p. 100 on average) related to improved right ventricular function in 7 cases. In 5 patients T48 was greater than 20 mg/l (max = 27.5) due to a fall in clearance (average -47 p. 100) which could have been caused by administration of erythromycin in 1 case and by dose-dependent kinetics in 2 cases. This protocol which is simple to carry out in practice allows early adjustment of dosage to give effective serum theophylline concentrations in over 50 p. 100 of cases. No serious cases of overdosage were observed, even in patients with high T0 and/or low initial clearances. Under-dosage and overdosage are related to large individual variations in theophylline clearance.

Aged↗
PubMed1984

Renal excretion of antidiuretic hormone in healthy subjects and patients with renal failure.

Urinary clearance of antidiuretic hormone (ADH) has been measured under basal conditions and during intravenous administration of arginine vasopressin in ten healthy subjects, and only under basal conditions in 18 patients with chronic renal failure and seven patients with acute renal failure at the polyuric phase of the disease. In healthy subjects studied under conditions of mild water diuresis plasma concentration, urinary excretion rate, urinary clearance and fractional clearance of ADH were 3.3 +/- 0.36 pg/ml, 25.2 +/- 5.5 pg/min, 7.5 +/- 1.2 ml/min and 6.4 +/- 1.0% (means +/- SEM) respectively. When plasma ADH was raised to levels between 7 and 26 pg/ml during intravenous administration of the hormone, urinary excretion rate and urinary clearance of ADH increased. Tubular reabsorption of ADH did not reach a plateau but progressively increased in the range of plasma ADH studied. In patients with chronic renal failure, plasma concentration, urinary excretion rate, urinary clearance and fractional clearance of ADH were 2.8 +/- 0.19 pg/ml, 9.4 +/- 2.0 pg/min, 3.4 +/- 0.6 ml/min and 10.0 +/- 2.9% (means +/- SEM) respectively. Urinary excretion rate and urinary clearance were significantly lower than in healthy subjects. In patients with acute renal failure, plasma concentration, urinary excretion rate, urinary clearance and fractional clearance of ADH were 4.6 +/- 0.47 pg/ml, 52.8 +/- 15.8 pg/min, 9.5 +/- 2.7 ml/min and 24.9 +/- 4.4% (means +/- SEM) respectively. Urinary excretion rate and fractional clearance were higher than in healthy subjects and patients with chronic renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗