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Biomedical subjects

M Lièvre

Publications and source records attributed to M Lièvre.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Remission of left ventricular hypertrophy with ramipril independently of blood pressure changes: the HYCAR study (cardiac hypertrophy and ramipril)].

Most studies of the regression of left ventricular hypertrophy by antihypertensive treatment have methodological weaknesses and have not shown if regression of left ventricular hypertrophy can be obtained independently of blood pressure reduction. In the HYCAR study, after an inclusion phase of 4 to 6 weeks on furosemide (20 mg/day), 115 patients with left ventricular hypertrophy were randomised in a double blind manner to placebo group (N = 40), ramipril, 1.25 mg/day, (N = 38) or 5 mg/day (N = 37) for a period of 6 months. Furosemide was continued during the double blind treatment period. Echocardiography and ambulatory blood pressure monitoring were performed just before the randomisation and at 6 months. At the end of the study, there was no significant difference between the casual and ambulatory blood pressure changes. Expressed in g/m, the left ventricular mass index decreased significantly with respect to placebo in the ramipril 5 mg group (-12.2 +/- 3.9 versus +5.5 +/- 4.3 g/m2, p = 0.003) and in the 1.25 mg group (-7.5 +/- 4.6 g/m2, p = 0.04). The reduction in left ventricular mass index expressed in g/m2 was significant in the 5 mg ramipril (p = 0.008) but not in the 1.25 mg ramipril group (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Calcium channel antagonists and myocardial ischemia or ischemia/reperfusion].

Many theoretical and experimental studies suggest that calcium antagonists drugs should be useful in pathological situations of myocardial ischemia or ischemia/reperfusion. This therapeutic model was tested in controlled trials of angina, post-infarction and cardiac surgery. The authors undertook a meta-analysis of these trials using the occurrence of myocardial infarction or death as criteria of judgement. No long-term benefits seem to be associated with the dihydropyridines such as nifedipine and nicardipine in anginal patients. In unstable angina, betablockers seem to be more effective but the difference is not statistically significant. In the post-infarction period, nifedipine does not reduce the risk of recurrence of myocardial infarction and may even increase the mortality by 15%, though this was not significant in the 9,055 patients studied (p = 0.08). Verapamil and diltiazem globally reduce the risk of recurrent infarction by 21% (p = 0.009) but not mortality (p = 0.52). Because of the small numbers of patients and the low prevalence of observed events, no useful conclusions can be drawn from studies of calcium antagonists in cardiac surgery. The results of the validation of the therapeutic model "calcium antagonists in pathological situation of myocardial ischemia or ischemia/reperfusion" does not justify the labels "anti-ischemics" or "cardio protectors" often applied to the calcium antagonists.

Calcium Channel Blockers↗
PubMed1992

[Technique for measuring the atheroma volume in men].

The evaluation of the impact of therapy on the evolution of atherosclerotic lesions or restenosis after angioplasty requires the use of techniques of vascular imaging. The reference invasive method is digital angiography although it does not provide data on the arterial wall thickness. This parameter can be approached however by intravascular ultrasound imaging, a technique which has a number of important practical limitations. Of the non-invasive techniques available, Doppler ultrasonography is the only one that can be used in clinical trials. Nuclear magnetic resonance imaging is the object of much research and is without doubt the technique of the future. The choice of model of atherosclerosis influences that of the imaging technique: cineangiography for coronary arteries, digital angiography or Doppler ultra sonography for lower limb arteries and Doppler ultrasonography for the carotid arteries. Interpretation of angiography is now performed quantitatively by videodensitometry. Interpretation of other techniques should be performed by a second independent observer and "blinded" with respect to the order in which the investigations were performed and to the treatment administered. The criteria of judgment may be qualitative (progression, stabilisation, regression) or quantitative, the latter having a number of advantages over the former. Of the quantitative criteria, the percentage stenosis, though widely used, does not fully answer the question posed, and neither does the diameter of the stenosis. The volume of the arterial lumen calculated from videodensitometric data would seem to be the best, by its sensitivity and additivity, current angiographic parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography, Digital Subtraction↗
PubMed1991

[Intermediary and substitution criteria in the development of anti-arrhythmia agents].

The traditional view that the suppression of arrhythmias (risk factor) after myocardial infarction can only be beneficial, has been queried by the results of the Cardiac Arrhythmia Suppression Trial (CAST) which showed increased mortality in two treatment groups. The methodology of trials of secondary prevention of myocardial infarction by antiarrhythmic agents partially explains why the reduction of anti-arrhythmias has come to be considered as a substitute for mortality in the assessment of drug efficacy. The authors define substitutive criteria and describe their three advantages (facility, correspondence, estimation). A meta-analysis of 6 trials of secondary prevention of myocardial infarction by Class I antiarrhythmics, in which the antiarrhythmic effect was evaluated (Holter monitoring) in parallel with mortality, shows that anti-arrhythmias were significantly reduced by nearly 60% (p = 10-8) whereas mortality remained unchanged (p = 0.41). A special graphic presentation of the results of these 6 trials shows that, even before the results of the CAST, it was clear that the suppression of antiarrhythmics was not a suitable substitutive end point for mortality.

Anti-Arrhythmia Agents↗
PubMed1991

[Class I anti-arrhythmia agents and prevention of sudden death following myocardial infarction].

The results of therapeutic trials of Class I antiarrhythmic agents after myocardial infarction are not identical or always compatible with those of the CAST. It is important to determine the reason for this disparity in order to try and identify the patients who should not be given these drugs and those in whom they could be beneficial, providing these benefits are clearly demonstrated. Meta-analyses of controlled therapeutic trials of Class I antiarrhythmics after myocardial infarction have been performed. Depending on the study protocol used, the results of the CAST are compatible or incompatible with those of other trials. A possible reason for this apparent discordance from meta-analysis could be the particularly low cardiac risk in the CAST patients.

Anti-Arrhythmia Agents↗
PubMed1985

Centrally mediated cardiovascular effects of nicergoline in the dog compared to those of clonidine.

The intracisternal administration of nicergoline (5 micrograms/kg) or clonidine (4 micrograms/kg) in chloralose-anesthetized dogs induced significant decreases in blood pressure and heart rate. The same dose of nicergoline induced similar effects on atropine-pretreated dogs. Guanethidine pretreatment (30 mg/kg i.v. the day before) prevented the hypotension but not the bradycardia induced by clonidine. Guanethidine prevented both the hypotension and the bradycardia induced by nicergoline. Thus, nicergoline, unlike clonidine, does not increase cardiac parasympathetic activity. When administered by the same route at the same doses, nicergoline did not change the slope and reduced the amplitude whereas clonidine increased both the slope and the amplitude of the heart period vs. blood pressure curve obtained by intravenous administration of phenylephrine. Taken together, these results suggest that nicergoline and clonidine probably act on different structures within the central nervous system.

Animals↗
PubMed1981

[Electrophysiological study of cardiac effects of succinylcholine: role of vagal tone and hyperkalemia in anesthetized dog (author's transl)].

The effects of intravenously infused succinylcholine (SCh): 1 mg/kg/minute during 30 minutes were assessed in anesthetized dogs on spontaneous heart rate, conduction within the atrio-ventricular node and the His-Purkinje system and on atrial (AERP) and atrio-ventricular (AVERP) effective refractory periods with varying levels of vagal tone and under mild hyperkalemia. 1) The heart rate which was not affected by SCh in the absence of vagal tone was by contrast increased by 50 p. cent when vagal tone was maintained. Under hyperkalemia, the vagolysis-mediated tachycardia did not prove more marked. 2) The conduction velocity, which was never modified by SCh in either the atria or the His-Purkinje system, was always accelerated with vagal tone. This acceleration is directly related to the vagolytic properties of SCh, but also partly to a mild hyperkalemia. The changes of potassium blood levels tend to reverse the potassium outflow due to the parasympathetic neuromediator. 3) The AERP was was lengthened by SCh and hyperkalemia; the latter impaired the outflow of potassium ions responsible for repolarization. The AVERP was always shortened when the vagal tone is maintained, however less largely under mild hyperkalemia which limits SCh anticholinergic effect owing to its own anticholinergic action.

Anesthesia, General↗
PubMedDate not supplied

Effects of two alpha-adrenoceptor antagonists, nicergoline and phentolamine, on myocardial oxygen consumption in the dog.

We compared the effects of two alpha-adrenoceptor antagonists, nicergoline and phentolamine, on myocardial oxygen consumption (MVO2) in open-chest dogs. Intravenous nicergoline, 2 micrograms/kg/min for 30 min, reduced blood pressure from 130 +/- 6 to 100 +/- 2 mm Hg, did not change heart rate, and reduced MVO2/beat from 63.1 +/- 6.6 to 43.6 +/- 4.0 microliters (p less than 0.05, compared with control saline-infused and phentolamine-treated dogs). Intravenous phentolamine, 8 micrograms/kg/min, reduced blood pressure from 123 +/- 6 to 95 +/- 8 mm Hg and increased heart rate from 199 +/- 4 to 235 +/- 9 beats/min ( p less than 0.05, compared with control and nicergoline-treated dogs). MVO2/beat did not change, but MVO2 increased from 11.1 +/- 1.5 to 13.1 +/- 2.0 ml/min (p less than 0.05, compared with nicergoline-treated dogs). These results suggest that nicergoline may be preferable to phentolamine in patients in whom it is important to avoid any increase in MVO2.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

[Evaluation criteria for protocols submitted to the consultant committee for protection of persons in biomedical research (CCPPRB) Lyon-C].

In order to fulfill its task, the Lyon-C institutional review board (CCPPRB) developed standards for the evaluation of clinical research protocols. This check-list envisages 1- the mandatory documents in the absence of which the protocol will not be considered, 2- scientific quality standards, 3- ethical quality standards. An agreement on the use of such standards in France might improve the functioning of institutional review boards (CCPPRB) and the quality of clinical research.

Clinical Protocols↗
PubMedDate not supplied

[Effects of hypocalcemia on atrioventricular conduction compared with those of agents which inhibit the slow channel (author's transl)].

1. The effects of experimental hypocalcemia were studied on 13 anesthetized and atropinized dogs, measuring endocavitary His bundle recordings, global effective refractory period (ERP) (determination by the extrastimulus method), and sinus rate. These data, including arterial pressure, were observed during a 40 min. I.V. infusion of Na EDTA, 3 mg . kg-1 . min-1. We observed: 1.1. A decrease in serum ionized calcium, from 45,7 mg . 1-1 (control) to 28,1 mg . 1-1 1.2. A moderate, though highly significant, decrease in the intraatrial conduction time (SA interval of His bundle recordings). 1.3. A significant increase in the AV node conduction time (AH). 1.4. No significant change in the His-Purkinje system conduction time (HV). 1.5. A significant increase in the global ERP, primarily involving the atrial contractile tissue ERP, and further the atrioventricular node ERP.

Animals↗
PubMedDate not supplied

[Evaluation of the potential cardiotoxicity of propranolol-lithium gluconate association (author's transl)].

The association B blocking agent-lithium salt is used for the therapy of some severe hyperthyroidism with cardiotoxicosis. Separately, both drugs depress intracardiac conduction. However by recording the potentials of the His bundle in anesthetized dogs, a potential cardiotoxicity of this association is unlikely since sinusal automaticity alone is importantly slowed. But, these results need further confirmation in man.

Animals↗